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Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claims; reliance on confirmation bias rather than rigorous attempts at refutation; lack of openness to evaluation by other experts; absence of systematic practices when developing hypotheses; and continued adherence long after the pseudoscientific hypotheses have been experimentally discredited. It is not the same as junk science. The demarcation between science and pseudoscience has scientific, philosophical, and political implications. Philosophers debate the nature of science and the general criteria for drawing the line between scientific theories and pseudoscientific beliefs, but there is widespread agreement "that creationism, astrology, homeopathy, Kirlian photography, dowsing, ufology, ancient astronaut theory, Holocaust denialism, Velikovskian catastrophism, and climate change denialism are pseudosciences." There are implications for health care, the use of expert testimony, and weighing environmental policies. Recent empirical research has shown that individuals who indulge in pseudoscientific beliefs generally show lower evidential criteria, meaning they often require significantly less evidence before coming to conclusions. This can be coined as a 'jump-to-conclusions' bias that can increase the spread of pseudoscientific beliefs. Addressing pseudoscience is part of science education and developing scientific literacy. Pseudoscience can have dangerous effects. For example, pseudoscientific anti-vaccine activism and promotion of homeopathic remedies as alternative disease treatments can result in people forgoing important medical treatments with demonstrable health benefits, leading to ill-health and deaths. Furthermore, people who refuse legitimate medical treatments for contagious diseases may put others at risk. Pseudoscientific theories about racial and ethnic classifications have led to racism and genocide. The term pseudoscience is often considered pejorative, particularly by its purveyors, because it suggests something is being presented as science inaccurately or even deceptively. Therefore, practitioners and advocates of pseudoscience frequently dispute the characterization. == Etymology == The word pseudoscience is derived from the Greek root pseudo meaning "false" and the English word science, from the Latin word scientia, meaning "knowledge". Although the term has been in use since at least the late 18th century (e.g., in 1796 by James Pettit Andrews in reference to alchemy), the concept of pseudoscience as distinct from real or proper science seems to have become more widespread during the mid-19th century. Among the earliest uses of "pseudo-science" was in an 1844 article in the Northern Journal of Medicine, issue 387: That opposite kind of innovation which pronounces what has been recognized as a branch of science, to have been a pseudo-science, composed merely of so-called facts, connected together by misapprehensions under the disguise of principles. An earlier use of the term was in 1843 by the French physiologist François Magendie, that refers to phrenology as "a pseudo-science of the present day". During the 20th century, the word was used pejoratively to describe explanations of phenomena which were claimed to be scientific, but which were not in fact supported by reliable experimental evidence. Dismissing the separate issue of intentional fraud – such as the Fox sisters' "rappings" in the 1850s – the pejorative label pseudoscience distinguishes the scientific 'us', at one extreme, from the pseudo-scientific 'them', at the other, and asserts that 'our' beliefs, practices, theories, etc., by contrast with that of 'the others', are scientific. There are four criteria: (a) the 'pseudoscientific' group asserts that its beliefs, practices, theories, etc., are 'scientific'; (b) the 'pseudoscientific' group claims that its allegedly established facts are justified true beliefs; (c) the 'pseudoscientific' group asserts that its 'established facts' have been justified by genuine, rigorous, scientific method; and (d) this assertion is false or deceptive: "it is not simply that subsequent evidence overturns established conclusions, but rather that the conclusions were never warranted in the first place" From time to time, however, the usage of the word occurred in a more formal, technical manner in response to a perceived threat to individual and institutional security in a social and cultural setting. == Relationship to science == Pseudoscience is differentiated from science because – although it usually claims to be science – pseudoscience does not adhere to scientific standards, such as the scientific method, falsifiability of claims, and Mertonian norms. === Scientific method === A number of basic principles are accepted by scientists as standards for determining whether a body of knowledge, method, or practice is scientific. Experimental results should be reproducible and verified by other researchers. These principles are intended to ensure experiments can be reproduced measurably given the same conditions, allowing further investigation to determine whether a hypothesis or theory related to given phenomena is valid and reliable. Standards require the scientific method to be applied throughout, and bias to be controlled for or eliminated through randomization, fair sampling procedures, blinding of studies, and other methods. All gathered data, including the experimental or environmental conditions, are expected to be documented for scrutiny and made available for peer review, allowing further experiments or studies to be conducted to confirm or falsify results. Statistical quantification of significance, confidence, and error are also important tools for the scientific method. === Falsifiability === During the mid-20th century, the philosopher Karl Popper emphasized the criterion of falsifiability to distinguish science from non-science. Statements, hypotheses, or theories have falsifiability or refutability if there is the inherent possibility that they can be proven false, that is, if it is possible to conceive of an observation or an argument that negates them. Popper used astrology and psychoanalysis as examples of pseudoscience and Einstein's theory of relativity as an example of science. He subdivided non-science into philosophical, mathematical, mythological, religious and metaphysical formulations on one hand, and pseudoscientific formulations on the other. Another example which shows the distinct need for a claim to be falsifiable was stated in Carl Sagan's publication The Demon-Haunted World when he discusses an invisible dragon that he has in his garage. The point is made that there is no physical test to refute the claim of the presence of this dragon. Whatever test one thinks can be devised, there is a reason why it does not apply to the invisible dragon, so one can never prove that the initial claim is wrong. Sagan concludes; "Now, what's the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all?". He states that "your inability to invalidate my hypothesis is not at all the same thing as proving it true", once again explaining that even if such a claim were true, it would be outside the realm of scientific inquiry. === Mertonian norms === During 1942, Robert K. Merton identified a set of five "norms" which characterize real science. If any of the norms were violated, Merton considered the enterprise to be non-science. His norms were: Originality: The tests and research done must present something new to the scientific community. Detachment: The scientists' reasons for practicing this science must be simply for the expansion of their knowledge. The scientists should not have personal reasons to expect certain results. Universality: No person should be able to more easily obtain the information of a test than another person. Social class, religion, ethnicity, or any other personal factors should not be factors in someone's ability to receive or perform a type of science. Skepticism: Scientific facts must not be based on faith. One should always question every case and argument and constantly check for errors or invalid claims. Public accessibility: Any scientific knowledge one obtains should be made available to everyone. The results of any research should be published and shared with the scientific community. === Refusal to acknowledge problems === In 1978, Paul Thagard proposed that pseudoscience is primarily distinguishable from science when it is less progressive than alternative theories over a long period of time, and its proponents fail to acknowledge or address problems with the theory. In 1983, Mario Bunge suggested the categories of "belief fields" and "research fields" to help distinguish between pseudoscience and science, where the former is primarily personal and subjective and the latter involves a certain systematic method. The 2018 book about scientific skepticism by Steven Novella, et al. The Skeptics' Guide to the Universe lists hostility to criticism as one of the major features of pseudoscience. === Criticism of the term === Larry Laudan has suggested pseudoscience has no scientific meaning and is mostly used to describe human emotions: "If we would stand up and be counted on the side of reason, we ought to drop terms like 'pseudo-science' and 'unscientific' from our vocabulary; they are just hollow phrases which do only emotive work for us". Likewise, Richard McNally states, "The term 'pseudoscience' has become little more than an inflammatory buzzword for quickly dismissing one's opponents in media sound-bites" and "When therapeutic entrepreneurs make claims on behalf of their interventions, we should not waste our time trying to determine whether their interventions qualify as pseudoscientific. Rather, we should ask them: How do you know that your intervention works? What is your evidence?" === Alternative definition === For philosophers Silvio Funtowicz and Jerome R. Ravetz "pseudo-science may be defined as one where the uncertainty of its inputs must be suppressed, lest they render its outputs totally indeterminate". The definition, in the book Uncertainty and Quality in Science for Policy, alludes to the loss of craft skills in handling quantitative information, and to the bad practice of achieving precision in prediction (inference) only at the expenses of ignoring uncertainty in the input which was used to formulate the prediction. This use of the term is common among practitioners of post-normal science. Understood in this way, pseudoscience can be fought using good practices to assess uncertainty in quantitative information, such as NUSAP and – in the case of mathematical modelling – sensitivity auditing. == History == The history of pseudoscience is the study of pseudoscientific theories over time. A pseudoscience is a set of ideas that presents itself as science, while it does not meet the criteria to be properly called such. Distinguishing between proper science and pseudoscience is sometimes difficult. One proposal for demarcation between the two is the falsification criterion, attributed most notably to the philosopher Karl Popper. In the history of science and the history of pseudoscience it can be especially difficult to separate the two, because some sciences developed from pseudosciences. An example of this transformation is the science of chemistry, which traces its origins to the pseudoscientific or pre-scientific study of alchemy. The vast diversity in pseudosciences further complicates the history of science. Some modern pseudosciences, such as astrology and acupuncture, originated before the scientific era. Others developed as part of an ideology, such as Lysenkoism, or as a response to perceived threats to an ideology. Examples of this ideological process are creation science and intelligent design, which were developed in response to the scientific theory of evolution. == Indicators of possible pseudoscience == A topic, practice, or body of knowledge might reasonably be termed pseudoscientific when it is presented as consistent with the norms of scientific research, but it demonstrably fails to meet these norms. === Use of vague, exaggerated or untestable claims === Assertion of scientific claims that are vague rather than precise, and that lack specific measurements. Assertion of a claim with little or no explanatory power. Failure to make use of operational definitions (i.e., publicly accessible definitions of the variables, terms, or objects of interest so that persons other than the definer can measure or test them independently) (See also: Reproducibility). Failure to make reasonable use of the principle of parsimony, i.e., failing to seek an explanation that requires the fewest possible additional assumptions when multiple viable explanations are possible (See: Occam's razor). Lack of boundary conditions: Most well-supported scientific theories possess well-articulated limitations under which the predicted phenomena do and do not apply. Lack of effective controls in experimental design, such as the use of placebos and double-blinding. Lack of understanding of basic and established principles of physics and engineering. === Improper collection of evidence === Assertions that do not allow the logical possibility that they can be shown to be false by observation or physical experiment (See also: Falsifiability). Assertion of claims that a theory predicts something that it has not been shown to predict. Scientific claims that do not confer any predictive power are considered at best "conjectures", or at worst "pseudoscience" (e.g., ignoratio elenchi). Assertion that claims which have not been proven false must therefore be true, and vice versa (See: Argument from ignorance). Over-reliance on testimonial, anecdotal evidence, or personal experience: This evidence may be useful for the context of discovery (i.e., hypothesis generation), but should not be used in the context of justification (e.g., statistical hypothesis testing). Use of myths and religious texts as if they were fact, or basing evidence on readings of such texts. Use of concepts and scenarios from science fiction as if they were fact. This technique appeals to the familiarity that many people already have with science fiction tropes through the popular media. Presentation of data that seems to support claims while suppressing or refusing to consider data that conflict with those claims. This is an example of selection bias or cherry picking, a distortion of evidence or data that arises from the way that the data are collected. It is sometimes referred to as the selection effect. Repeating excessive or untested claims that have been previously published elsewhere, and promoting those claims as if they were facts; an accumulation of such uncritical secondary reports, which do not otherwise contribute their own empirical investigation, is called the Woozle effect. Reversed burden of proof: science places the burden of proof on those making a claim, not on the critic. "Pseudoscientific" arguments may neglect this principle and demand that skeptics demonstrate beyond a reasonable doubt that a claim (e.g., an assertion regarding the efficacy of a novel therapeutic technique) is false. It is essentially impossible to prove a universal negative, so this tactic incorrectly places the burden of proof on the skeptic rather than on the claimant. Appeals to holism as opposed to reductionism to dismiss negative findings: proponents of pseudoscientific claims, especially in organic medicine, alternative medicine, naturopathy and mental health, often resort to the "mantra of holism" . === Lack of openness to testing by other experts === Evasion of peer review before publicizing results (termed "science by press conference"): Some proponents of ideas that contradict accepted scientific theories avoid subjecting their ideas to peer review, sometimes on the grounds that peer review is biased towards established paradigms, and sometimes on the grounds that assertions cannot be evaluated adequately using standard scientific methods. By remaining insulated from the peer review process, these proponents forgo the opportunity of corrective feedback from informed colleagues. Some agencies, institutions, and publications that fund scientific research require authors to share data so others can evaluate a paper independently. Failure to provide adequate information for other researchers to reproduce the claims contributes to a lack of openness. Appealing to the need for secrecy or proprietary knowledge when an independent review of data or methodology is requested. Substantive debate on the evidence by knowledgeable proponents of all viewpoints is not encouraged. === Absence of progress === Failure to progress towards additional evidence of its claims. Terence Hines has identified astrology as a subject that has changed very little in the past two millennia. Lack of self-correction: scientific research programmes make mistakes, but they tend to reduce these errors over time. By contrast, ideas may be regarded as pseudoscientific because they have remained unaltered despite contradictory evidence. The work Scientists Confront Velikovsky (1976) Cornell University, also delves into these features in some detail, as does the work of Thomas Kuhn, e.g., The Structure of Scientific Revolutions (1962) which also discusses some of the items on the list of characteristics of pseudoscience. Statistical significance of supporting experimental results does not improve over time and are usually close to the cutoff for statistical significance. Normally, experimental techniques improve or the experiments are repeated, and this gives ever stronger evidence. If statistical significance does not improve, this typically shows the experiments have just been repeated until a success occurs due to chance variations. === Personalization of issues === Tight social groups and authoritarian personality, suppression of dissent and groupthink can enhance the adoption of beliefs that have no rational basis. In attempting to confirm their beliefs, the group tends to identify their critics as enemies. Assertion of a conspiracy on the part of the mainstream scientific community, government, or educational facilities to suppress pseudoscientific information. People who make these accusations often compare themselves to Galileo Galilei and his persecution by the Roman Catholic Church; this comparison is commonly known as the Galileo gambit. Attacking the motives, character, morality, or competence of critics, rather than their arguments (see ad hominem) === Use of misleading language === Creating scientific-sounding terms to persuade non-experts to believe statements that may be false or meaningless: for example, a long-standing hoax refers to water by the rarely used formal name "dihydrogen monoxide" and describes it as the main constituent in most poisonous solutions to show how easily the general public can be misled. Using established terms in idiosyncratic ways, thereby demonstrating unfamiliarity with mainstream work in the discipline. == Prevalence of pseudoscientific beliefs == === Countries === The Ministry of AYUSH in the Government of India is purposed with developing education, research and propagation of indigenous alternative medicine systems in India. The ministry has faced significant criticism for funding systems that lack biological plausibility and are either untested or conclusively proven as ineffective. Quality of research has been poor, and drugs have been launched without any rigorous pharmacological studies and meaningful clinical trials on Ayurveda or other alternative healthcare systems. There is no credible efficacy or scientific basis of any of these forms of treatment. In his book The Demon-Haunted World, Carl Sagan discusses the government of China and the Chinese Communist Party's concern about Western pseudoscience developments and certain ancient Chinese practices in China. He sees pseudoscience occurring in the United States as part of a worldwide trend and suggests its causes, dangers, diagnosis and treatment may be universal. A large percentage of the United States population lacks scientific literacy, not adequately understanding scientific principles and method. In the Journal of College Science Teaching, Art Hobson writes, "Pseudoscientific beliefs are surprisingly widespread in our culture even among public school science teachers and newspaper editors, and are closely related to scientific illiteracy." However, a 10,000-student study in the same journal concluded there was no strong correlation between science knowledge and belief in pseudoscience. During 2006, the U.S. National Science Foundation (NSF) issued an executive summary of a paper on science and engineering which briefly discussed the prevalence of pseudoscience in modern times. It said, "belief in pseudoscience is widespread" and, referencing a Gallup Poll, stated that belief in the 10 commonly believed examples of paranormal phenomena listed in the poll were "pseudoscientific beliefs". The items were "extrasensory perception (ESP), that houses can be haunted, ghosts, telepathy, clairvoyance, astrology, that people can mentally communicate with the dead, witches, reincarnation, and channelling". Such beliefs in pseudoscience represent a lack of knowledge of how science works. The scientific community may attempt to communicate information about science out of concern for the public's susceptibility to unproven claims. The NSF stated that pseudoscientific beliefs in the U.S. became more widespread during the 1990s, peaked about 2001, and then decreased slightly since with pseudoscientific beliefs remaining common. According to the NSF report, there is a lack of knowledge of pseudoscientific issues in society and pseudoscientific practices are commonly followed. Surveys indicate about a third of adult Americans consider astrology to be scientific. In Russia, in the late 20th and early 21st century, significant budgetary funds were spent on programs for the experimental study of "torsion fields", the extraction of energy from granite, the study of "cold nuclear fusion", and astrological and extrasensory "research" by the Ministry of Defense, the Ministry of Emergency Situations, the Ministry of Internal Affairs, and the State Duma (see Military Unit 10003). In 2006, Deputy Chairman of the Security Council of the Russian Federation Nikolai Spassky published an article in Rossiyskaya Gazeta, where among the priority areas for the development of the Russian energy sector, the task of extracting energy from a vacuum was in the first place. The Clean Water project was adopted as a United Russia party project; in the version submitted to the government, the program budget for 2010–2017 exceeded $14 billion. === Racism === There have been many connections between pseudoscientific writers and researchers and their anti-semitic, racist and neo-Nazi backgrounds. They often use pseudoscience to reinforce their beliefs. One of the most predominant pseudoscientific writers is Frank Collin, a self-proclaimed Nazi who goes by Frank Joseph in his writings. The majority of his works include the topics of Atlantis, extraterrestrial encounters, and Lemuria as well as other ancient civilizations, often with white supremacist undertones. For example, he posited that European peoples migrated to North America before Columbus, and that all Native American civilizations were initiated by descendants of white people. The Alt-Right using pseudoscience to base their ideologies on is not a new issue. The entire foundation of anti-semitism is based on pseudoscience, or scientific racism. In an article from Newsweek by Sander Gilman, Gilman describes the pseudoscience community's anti-semitic views. "Jews as they appear in this world of pseudoscience are an invented group of ill, stupid or stupidly smart people who use science to their own nefarious ends. Other groups, too, are painted similarly in 'race science', as it used to call itself: African-Americans, the Irish, the Chinese and, well, any and all groups that you want to prove inferior to yourself". Neo-Nazis and white supremacist often try to support their claims with studies that "prove" that their claims are more than just harmful stereotypes. For example Bret Stephens published a column in The New York Times where he claimed that Ashkenazi Jews had the highest IQ among any ethnic group. However, the scientific methodology and conclusions reached by the article Stephens cited has been called into question repeatedly since its publication. It has been found that at least one of that study's authors has been identified by the Southern Poverty Law Center as a white nationalist. The journal Nature has published a number of editorials in the last few years warning researchers about extremists looking to abuse their work, particularly population geneticists and those working with ancient DNA. One article in Nature, titled "Racism in Science: The Taint That Lingers" notes that early-twentieth-century eugenic pseudoscience has been used to influence public policy, such as the Immigration Act of 1924 in the United States, which sought to prevent immigration from Asia and parts of Europe. == Explanations == In a 1981 report Singer and Benassi wrote that pseudoscientific beliefs have their origin from at least four sources: Common cognitive errors from personal experience Erroneous sensationalistic mass media coverage Sociocultural factors Poor or erroneous science education A 1990 study by Eve and Dunn supported the findings of Singer and Benassi and found pseudoscientific belief being promoted by high school life science and biology teachers. === Psychology === The psychology of pseudoscience attempts to explore and analyze pseudoscientific thinking by means of thorough clarification on making the distinction of what is considered scientific vs. pseudoscientific. The human proclivity for seeking confirmation rather than refutation (confirmation bias), the tendency to hold comforting beliefs, and the tendency to overgeneralize have been proposed as reasons for pseudoscientific thinking. According to Beyerstein, humans are prone to associations based on resemblances only, and often prone to misattribution in cause-effect thinking. Michael Shermer's theory of belief-dependent realism is driven by the idea that the brain is essentially a "belief engine" which scans data perceived by the senses and looks for patterns and meaning. There is also the tendency for the brain to create cognitive biases, as a result of inferences and assumptions made without logic and based on instinct – usually resulting in patterns in cognition. These tendencies of patternicity and agenticity are also driven "by a meta-bias called the bias blind spot, or the tendency to recognize the power of cognitive biases in other people but to be blind to their influence on our own beliefs". Lindeman states that social motives (i.e., "to comprehend self and the world, to have a sense of control over outcomes, to belong, to find the world benevolent and to maintain one's self-esteem") are often "more easily" fulfilled by pseudoscience than by scientific information. Furthermore, pseudoscientific explanations are generally not analyzed rationally, but instead experientially. Operating within a different set of rules compared to rational thinking, experiential thinking regards an explanation as valid if the explanation is "personally functional, satisfying and sufficient", offering a description of the world that may be more personal than can be provided by science and reducing the amount of potential work involved in understanding complex events and outcomes. Anyone searching for psychological help that is based in science should seek a licensed therapist whose techniques are not based in pseudoscience. Hupp and Santa Maria provide a complete explanation of what that person should look for. === Education and scientific literacy === There is a trend to believe in pseudoscience more than scientific evidence. Some people believe the prevalence of pseudoscientific beliefs is due to widespread scientific illiteracy. Individuals lacking scientific literacy are more susceptible to wishful thinking, since they are likely to turn to immediate gratification powered by System 1, our default operating system which requires little to no effort. This system encourages one to accept the conclusions they believe, and reject the ones they do not. Further analysis of complex pseudoscientific phenomena require System 2, which follows rules, compares objects along multiple dimensions and weighs options. These two systems have several other differences which are further discussed in the dual-process theory. The scientific and secular systems of morality and meaning are generally unsatisfying to most people. Humans are, by nature, a forward-minded species pursuing greater avenues of happiness and satisfaction, but we are all too frequently willing to grasp at unrealistic promises of a better life. Psychology has much to discuss about pseudoscience thinking, as it is the illusory perceptions of causality and effectiveness of numerous individuals that needs to be illuminated. Research suggests that illusionary thinking happens in most people when exposed to certain circumstances such as reading a book, an advertisement or the testimony of others are the basis of pseudoscience beliefs. It is assumed that illusions are not unusual, and given the right conditions, illusions are able to occur systematically even in normal emotional situations. One of the things pseudoscience believers quibble most about is that academic science usually treats them as fools. Minimizing these illusions in the real world is not simple. To this aim, designing evidence-based educational programs can be effective to help people identify and reduce their own illusions. == Boundaries with science == === Classification === Philosophers classify types of knowledge. In English, the word science is used to indicate specifically the natural sciences and related fields, which are called the social sciences. Different philosophers of science may disagree on the exact limits – for example, is mathematics a formal science that is closer to the empirical ones, or is pure mathematics closer to the philosophical study of logic and therefore not a science? – but all agree that all of the ideas that are not scientific are non-scientific. The large category of non-science includes all matters outside the natural and social sciences, such as the study of history, metaphysics, religion, art, and the humanities. Dividing the category again, unscientific claims are a subset of the large category of non-scientific claims. This category specifically includes all matters that are directly opposed to good science. Un-science includes both "bad science" (such as an error made in a good-faith attempt at learning something about the natural world) and pseudoscience. Thus pseudoscience is a subset of un-science, and un-science, in turn, is subset of non-science. Science is also distinguishable from revelation, theology, or spirituality in that it offers insight into the physical world obtained by empirical research and testing. The most notable disputes concern the evolution of living organisms, the idea of common descent, the geologic history of the Earth, the formation of the Solar System, and the origin of the universe. Systems of belief that derive from divine or inspired knowledge are not considered pseudoscience if they do not claim either to be scientific or to overturn well-established science. Moreover, some specific religious claims, such as the power of intercessory prayer to heal the sick, although they may be based on untestable beliefs, can be tested by the scientific method. Some statements and common beliefs of popular science may not meet the criteria of science. "Pop" science may blur the divide between science and pseudoscience among the general public, and may also involve science fiction. Indeed, pop science is disseminated to, and can also easily emanate from, persons not accountable to scientific methodology and expert peer review. If claims of a given field can be tested experimentally and standards are upheld, it is not pseudoscience, regardless of how odd, astonishing, or counterintuitive those claims are. If claims made are inconsistent with existing experimental results or established theory, but the method is sound, caution should be used, since science consists of testing hypotheses which may turn out to be false. In such a case, the work may be better described as ideas that are "not yet generally accepted". Protoscience is a term sometimes used to describe a hypothesis that has not yet been tested adequately by the scientific method, but which is otherwise consistent with existing science or which, where inconsistent, offers reasonable account of the inconsistency. It may also describe the transition from a body of practical knowledge into a scientific field. === Philosophy === Karl Popper stated it is insufficient to distinguish science from pseudoscience, or from metaphysics (such as the philosophical question of what existence means), by the criterion of rigorous adherence to the empirical method, which is essentially inductive, based on observation or experimentation. He proposed a method to distinguish between genuine empirical, nonempirical or even pseudoempirical methods. The latter case was exemplified by astrology, which appeals to observation and experimentation. While it had empirical evidence based on observation, on horoscopes and biographies, it crucially failed to use acceptable scientific standards. Popper proposed falsifiability as an important criterion in distinguishing science from pseudoscience. To demonstrate this point, Popper gave two cases of human behavior and typical explanations from Sigmund Freud and Alfred Adler's theories: "that of a man who pushes a child into the water with the intention of drowning it; and that of a man who sacrifices his life in an attempt to save the child." From Freud's perspective, the first man would have suffered from psychological repression, probably originating from an Oedipus complex, whereas the second man had attained sublimation. From Adler's perspective, the first and second man suffered from feelings of inferiority and had to prove himself, which drove him to commit the crime or, in the second case, drove him to rescue the child. Popper was not able to find any counterexamples of human behavior in which the behavior could not be explained in the terms of Adler's or Freud's theory. Popper argued it was that the observation always fitted or confirmed the theory which, rather than being its strength, was actually its weakness. In contrast, Popper gave the example of Einstein's gravitational theory, which predicted "light must be attracted by heavy bodies (such as the Sun), precisely as material bodies were attracted." Following from this, stars closer to the Sun would appear to have moved a small distance away from the Sun, and away from each other. This prediction was particularly striking to Popper because it involved considerable risk. The brightness of the Sun prevented this effect from being observed under normal circumstances, so photographs had to be taken during an eclipse and compared to photographs taken at night. Popper states, "If observation shows that the predicted effect is definitely absent, then the theory is simply refuted." Popper summed up his criterion for the scientific status of a theory as depending on its falsifiability, refutability, or testability. Paul R. Thagard used astrology as a case study to distinguish science from pseudoscience and proposed principles and criteria to delineate them. First, astrology has not progressed in that it has not been updated nor added any explanatory power since Ptolemy. Second, it has ignored outstanding problems such as the precession of equinoxes in astronomy. Third, alternative theories of personality and behavior have grown progressively to encompass explanations of phenomena which astrology statically attributes to heavenly forces. Fourth, astrologers have remained uninterested in furthering the theory to deal with outstanding problems or in critically evaluating the theory in relation to other theories. Thagard intended this criterion to be extended to areas other than astrology. He believed it would delineate as pseudoscientific such practices as witchcraft and pyramidology, while leaving physics, chemistry, astronomy, geoscience, biology, and archaeology in the realm of science. In the philosophy and history of science, Imre Lakatos stresses the social and political importance of the demarcation problem, the normative methodological problem of distinguishing between science and pseudoscience. His distinctive historical analysis of scientific methodology based on research programmes suggests: "scientists regard the successful theoretical prediction of stunning novel facts – such as the return of Halley's comet or the gravitational bending of light rays – as what demarcates good scientific theories from pseudo-scientific and degenerate theories, and in spite of all scientific theories being forever confronted by 'an ocean of counterexamples'". Lakatos offers a "novel fallibilist analysis of the development of Newton's celestial dynamics, [his] favourite historical example of his methodology" and argues in light of this historical turn, that his account answers for certain inadequacies in those of Karl Popper and Thomas Kuhn. "Nonetheless, Lakatos did recognize the force of Kuhn's historical criticism of Popper – all important theories have been surrounded by an 'ocean of anomalies', which on a falsificationist view would require the rejection of the theory outright...Lakatos sought to reconcile the rationalism of Popperian falsificationism with what seemed to be its own refutation by history". Many philosophers have tried to solve the problem of demarcation in the following terms: a statement constitutes knowledge if sufficiently many people believe it sufficiently strongly. But the history of thought shows us that many people were totally committed to absurd beliefs. If the strengths of beliefs were a hallmark of knowledge, we should have to rank some tales about demons, angels, devils, and of heaven and hell as knowledge. Scientists, on the other hand, are very sceptical even of their best theories. Newton's is the most powerful theory science has yet produced, but Newton himself never believed that bodies attract each other at a distance. So no degree of commitment to beliefs makes them knowledge. Indeed, the hallmark of scientific behaviour is a certain scepticism even towards one's most cherished theories. Blind commitment to a theory is not an intellectual virtue: it is an intellectual crime. Thus a statement may be pseudoscientific even if it is eminently 'plausible' and everybody believes in it, and it may be scientifically valuable even if it is unbelievable and nobody believes in it. A theory may even be of supreme scientific value even if no one understands it, let alone believes in it. The boundary between science and pseudoscience is disputed and difficult to determine analytically, even after more than a century of study by philosophers of science and scientists, and despite some basic agreements on the fundamentals of the scientific method. The concept of pseudoscience rests on an understanding that the scientific method has been misrepresented or misapplied with respect to a given theory, but many philosophers of science maintain that different kinds of methods are held as appropriate across different fields and different eras of human history. According to Lakatos, the typical descriptive unit of great scientific achievements is not an isolated hypothesis but "a powerful problem-solving machinery, which, with the help of sophisticated mathematical techniques, digests anomalies and even turns them into positive evidence". To Popper, pseudoscience uses induction to generate theories, and only performs experiments to seek to verify them. To Popper, falsifiability is what determines the scientific status of a theory. Taking a historical approach, Kuhn observed that scientists did not follow Popper's rule, and might ignore falsifying data, unless overwhelming. To Kuhn, puzzle-solving within a paradigm is science. Lakatos attempted to resolve this debate, by suggesting history shows that science occurs in research programmes, competing according to how progressive they are. The leading idea of a programme could evolve, driven by its heuristic to make predictions that can be supported by evidence. Feyerabend claimed that Lakatos was selective in his examples, and the whole history of science shows there is no universal rule of scientific method, and imposing one on the scientific community impedes progress. Laudan maintained that the demarcation between science and non-science was a pseudo-problem, preferring to focus on the more general distinction between reliable and unreliable knowledge. [Feyerabend] regards Lakatos's view as being closet anarchism disguised as methodological rationalism. Feyerabend's claim was not that standard methodological rules should never be obeyed, but rather that sometimes progress is made by abandoning them. In the absence of a generally accepted rule, there is a need for alternative methods of persuasion. According to Feyerabend, Galileo employed stylistic and rhetorical techniques to convince his reader, while he also wrote in Italian rather than Latin and directed his arguments to those already temperamentally inclined to accept them. == Politics, health, and education == === Political implications === The demarcation problem between science and pseudoscience brings up debate in the realms of science, philosophy and politics. Imre Lakatos, for instance, points out that the Communist Party of the Soviet Union at one point declared that Mendelian genetics was pseudoscientific and had its advocates, including well-established scientists such as Nikolai Vavilov, sent to a Gulag and that the "liberal Establishment of the West" denies freedom of speech to topics it regards as pseudoscience, particularly where they run up against social mores. Something becomes pseudoscientific when science cannot be separated from ideology, scientists misrepresent scientific findings to promote or draw attention for publicity, when politicians, journalists and a nation's intellectual elite distort the facts of science for short-term political gain, or when powerful individuals of the public conflate causation and cofactors by clever wordplay. These ideas reduce the authority, value, integrity and independence of science in society. === Health and education implications === Distinguishing science from pseudoscience has practical implications in the case of health care, expert testimony, environmental policies, and science education. Treatments with a patina of scientific authority which have not actually been subjected to actual scientific testing may be ineffective, expensive and dangerous to patients and confuse health providers, insurers, government decision makers and the public as to what treatments are appropriate. Claims advanced by pseudoscience may result in government officials and educators making bad decisions in selecting curricula. The extent to which students acquire a range of social and cognitive thinking skills related to the proper usage of science and technology determines whether they are scientifically literate. Education in the sciences encounters new dimensions with the changing landscape of science and technology, a fast-changing culture and a knowledge-driven era. A reinvention of the school science curriculum is one that shapes students to contend with its changing influence on human welfare. Scientific literacy, which allows a person to distinguish science from pseudosciences such as astrology, is among the attributes that enable students to adapt to the changing world. Its characteristics are embedded in a curriculum where students are engaged in resolving problems, conducting investigations, or developing projects. Alan J. Friedman mentions why most scientists avoid educating about pseudoscience, including that paying undue attention to pseudoscience could dignify it. On the other hand, Robert L. Park emphasizes how pseudoscience can be a threat to society and considers that scientists have a responsibility to teach how to distinguish science from pseudoscience. Pseudosciences such as homeopathy, even if generally benign, are used by charlatans. This poses a serious issue because it enables incompetent practitioners to administer health care. True-believing zealots may pose a more serious threat than typical con men because of their delusion to homeopathy's ideology. Irrational health care is not harmless and it is careless to create patient confidence in pseudomedicine. On 8 December 2016, journalist Michael V. LeVine pointed out the dangers posed by the Natural News website: "Snake-oil salesmen have pushed false cures since the dawn of medicine, and now websites like Natural News flood social media with dangerous anti-pharmaceutical, anti-vaccination and anti-GMO pseudoscience that puts millions at risk of contracting preventable illnesses." The anti-vaccine movement has persuaded large numbers of parents not to vaccinate their children, citing pseudoscientific research that links childhood vaccines with the onset of autism. These include the study by Andrew Wakefield, which claimed that a combination of gastrointestinal disease and developmental regression, which are often seen in children with ASD, occurred within two weeks of receiving vaccines. The study was eventually retracted by its publisher, and Wakefield was stripped of his license to practice medicine. Alkaline water is water that has a pH of higher than 7, purported to host numerous health benefits, with no empirical backing. A practitioner known as Robert O. Young who promoted alkaline water and an "Alkaline diet" was sent to jail for 3 years in 2017 for practicing medicine without a license. == See also == == Notes == == References == == Bibliography == === Works cited === === Further reading ===
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https://en.wikipedia.org/wiki/Pseudoscience
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Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including observation, experimentation, and mathematical modeling. Modern biology is grounded in the theory of evolution by natural selection, first articulated by Charles Darwin, and in the molecular understanding of genes encoded in DNA. The discovery of the structure of DNA and advances in molecular genetics have transformed many areas of biology, leading to applications in medicine, agriculture, biotechnology, and environmental science. Life on Earth is believed to have originated over 3.7 billion years ago. Today, it includes a vast diversity of organisms—from single-celled archaea and bacteria to complex multicellular plants, fungi, and animals. Biologists classify organisms based on shared characteristics and evolutionary relationships, using taxonomic and phylogenetic frameworks. These organisms interact with each other and with their environments in ecosystems, where they play roles in energy flow and nutrient cycling. As a constantly evolving field, biology incorporates new discoveries and technologies that enhance the understanding of life and its processes, while contributing to solutions for challenges such as disease, climate change, and biodiversity loss. == History == The earliest of roots of science, which included medicine, can be traced to ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions shaped ancient Greek natural philosophy. Ancient Greek philosophers such as Aristotle (384–322 BCE) contributed extensively to the development of biological knowledge. He explored biological causation and the diversity of life. His successor, Theophrastus, began the scientific study of plants. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz (781–869), Al-Dīnawarī (828–896), who wrote on botany, and Rhazes (865–925) who wrote on anatomy and physiology. Medicine was especially well studied by Islamic scholars working in Greek philosopher traditions, while natural history drew heavily on Aristotelian thought. Biology began to quickly develop with Anton van Leeuwenhoek's dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria and the diversity of microscopic life. Investigations by Jan Swammerdam led to new interest in entomology and helped to develop techniques of microscopic dissection and staining. Advances in microscopy had a profound impact on biological thinking. In the early 19th century, biologists pointed to the central importance of the cell. In 1838, Schleiden and Schwann began promoting the now universal ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of life, although they opposed the idea that (3) all cells come from the division of other cells, continuing to support spontaneous generation. However, Robert Remak and Rudolf Virchow were able to reify the third tenet, and by the 1860s most biologists accepted all three tenets which consolidated into cell theory. Meanwhile, taxonomy and classification became the focus of natural historians. Carl Linnaeus published a basic taxonomy for the natural world in 1735, and in the 1750s introduced scientific names for all his species. Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of common descent. Serious evolutionary thinking originated with the works of Jean-Baptiste Lamarck, who presented a coherent theory of evolution. The British naturalist Charles Darwin, combining the biogeographical approach of Humboldt, the uniformitarian geology of Lyell, Malthus's writings on population growth, and his own morphological expertise and extensive natural observations, forged a more successful evolutionary theory based on natural selection; similar reasoning and evidence led Alfred Russel Wallace to independently reach the same conclusions. The basis for modern genetics began with the work of Gregor Mendel in 1865. This outlined the principles of biological inheritance. However, the significance of his work was not realized until the early 20th century when evolution became a unified theory as the modern synthesis reconciled Darwinian evolution with classical genetics. In the 1940s and early 1950s, a series of experiments by Alfred Hershey and Martha Chase pointed to DNA as the component of chromosomes that held the trait-carrying units that had become known as genes. A focus on new kinds of model organisms such as viruses and bacteria, along with the discovery of the double-helical structure of DNA by James Watson and Francis Crick in 1953, marked the transition to the era of molecular genetics. From the 1950s onwards, biology has been vastly extended in the molecular domain. The genetic code was cracked by Har Gobind Khorana, Robert W. Holley and Marshall Warren Nirenberg after DNA was understood to contain codons. The Human Genome Project was launched in 1990 to map the human genome. == Chemical basis == === Atoms and molecules === All organisms are made up of chemical elements; oxygen, carbon, hydrogen, and nitrogen account for most (96%) of the mass of all organisms, with calcium, phosphorus, sulfur, sodium, chlorine, and magnesium constituting essentially all the remainder. Different elements can combine to form compounds such as water, which is fundamental to life. Biochemistry is the study of chemical processes within and relating to living organisms. Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including molecular synthesis, modification, mechanisms, and interactions. === Water === Life arose from the Earth's first ocean, which formed some 3.8 billion years ago. Since then, water continues to be the most abundant molecule in every organism. Water is important to life because it is an effective solvent, capable of dissolving solutes such as sodium and chloride ions or other small molecules to form an aqueous solution. Once dissolved in water, these solutes are more likely to come in contact with one another and therefore take part in chemical reactions that sustain life. In terms of its molecular structure, water is a small polar molecule with a bent shape formed by the polar covalent bonds of two hydrogen (H) atoms to one oxygen (O) atom (H2O). Because the O–H bonds are polar, the oxygen atom has a slight negative charge and the two hydrogen atoms have a slight positive charge. This polar property of water allows it to attract other water molecules via hydrogen bonds, which makes water cohesive. Surface tension results from the cohesive force due to the attraction between molecules at the surface of the liquid. Water is also adhesive as it is able to adhere to the surface of any polar or charged non-water molecules. Water is denser as a liquid than it is as a solid (or ice). This unique property of water allows ice to float above liquid water such as ponds, lakes, and oceans, thereby insulating the liquid below from the cold air above. Water has the capacity to absorb energy, giving it a higher specific heat capacity than other solvents such as ethanol. Thus, a large amount of energy is needed to break the hydrogen bonds between water molecules to convert liquid water into water vapor. As a molecule, water is not completely stable as each water molecule continuously dissociates into hydrogen and hydroxyl ions before reforming into a water molecule again. In pure water, the number of hydrogen ions balances (or equals) the number of hydroxyl ions, resulting in a pH that is neutral. === Organic compounds === Organic compounds are molecules that contain carbon bonded to another element such as hydrogen. With the exception of water, nearly all the molecules that make up each organism contain carbon. Carbon can form covalent bonds with up to four other atoms, enabling it to form diverse, large, and complex molecules. For example, a single carbon atom can form four single covalent bonds such as in methane, two double covalent bonds such as in carbon dioxide (CO2), or a triple covalent bond such as in carbon monoxide (CO). Moreover, carbon can form very long chains of interconnecting carbon–carbon bonds such as octane or ring-like structures such as glucose. The simplest form of an organic molecule is the hydrocarbon, which is a large family of organic compounds that are composed of hydrogen atoms bonded to a chain of carbon atoms. A hydrocarbon backbone can be substituted by other elements such as oxygen (O), hydrogen (H), phosphorus (P), and sulfur (S), which can change the chemical behavior of that compound. Groups of atoms that contain these elements (O-, H-, P-, and S-) and are bonded to a central carbon atom or skeleton are called functional groups. There are six prominent functional groups that can be found in organisms: amino group, carboxyl group, carbonyl group, hydroxyl group, phosphate group, and sulfhydryl group. In 1953, the Miller–Urey experiment showed that organic compounds could be synthesized abiotically within a closed system mimicking the conditions of early Earth, thus suggesting that complex organic molecules could have arisen spontaneously in early Earth (see abiogenesis). === Macromolecules === Macromolecules are large molecules made up of smaller subunits or monomers. Monomers include sugars, amino acids, and nucleotides. Carbohydrates include monomers and polymers of sugars. Lipids are the only class of macromolecules that are not made up of polymers. They include steroids, phospholipids, and fats, largely nonpolar and hydrophobic (water-repelling) substances. Proteins are the most diverse of the macromolecules. They include enzymes, transport proteins, large signaling molecules, antibodies, and structural proteins. The basic unit (or monomer) of a protein is an amino acid. Twenty amino acids are used in proteins. Nucleic acids are polymers of nucleotides. Their function is to store, transmit, and express hereditary information. == Cells == Cell theory states that cells are the fundamental units of life, that all living things are composed of one or more cells, and that all cells arise from preexisting cells through cell division. Most cells are very small, with diameters ranging from 1 to 100 micrometers and are therefore only visible under a light or electron microscope. There are generally two types of cells: eukaryotic cells, which contain a nucleus, and prokaryotic cells, which do not. Prokaryotes are single-celled organisms such as bacteria, whereas eukaryotes can be single-celled or multicellular. In multicellular organisms, every cell in the organism's body is derived ultimately from a single cell in a fertilized egg. === Cell structure === Every cell is enclosed within a cell membrane that separates its cytoplasm from the extracellular space. A cell membrane consists of a lipid bilayer, including cholesterols that sit between phospholipids to maintain their fluidity at various temperatures. Cell membranes are semipermeable, allowing small molecules such as oxygen, carbon dioxide, and water to pass through while restricting the movement of larger molecules and charged particles such as ions. Cell membranes also contain membrane proteins, including integral membrane proteins that go across the membrane serving as membrane transporters, and peripheral proteins that loosely attach to the outer side of the cell membrane, acting as enzymes shaping the cell. Cell membranes are involved in various cellular processes such as cell adhesion, storing electrical energy, and cell signalling and serve as the attachment surface for several extracellular structures such as a cell wall, glycocalyx, and cytoskeleton. Within the cytoplasm of a cell, there are many biomolecules such as proteins and nucleic acids. In addition to biomolecules, eukaryotic cells have specialized structures called organelles that have their own lipid bilayers or are spatially units. These organelles include the cell nucleus, which contains most of the cell's DNA, or mitochondria, which generate adenosine triphosphate (ATP) to power cellular processes. Other organelles such as endoplasmic reticulum and Golgi apparatus play a role in the synthesis and packaging of proteins, respectively. Biomolecules such as proteins can be engulfed by lysosomes, another specialized organelle. Plant cells have additional organelles that distinguish them from animal cells such as a cell wall that provides support for the plant cell, chloroplasts that harvest sunlight energy to produce sugar, and vacuoles that provide storage and structural support as well as being involved in reproduction and breakdown of plant seeds. Eukaryotic cells also have cytoskeleton that is made up of microtubules, intermediate filaments, and microfilaments, all of which provide support for the cell and are involved in the movement of the cell and its organelles. In terms of their structural composition, the microtubules are made up of tubulin (e.g., α-tubulin and β-tubulin) whereas intermediate filaments are made up of fibrous proteins. Microfilaments are made up of actin molecules that interact with other strands of proteins. === Metabolism === All cells require energy to sustain cellular processes. Metabolism is the set of chemical reactions in an organism. The three main purposes of metabolism are: the conversion of food to energy to run cellular processes; the conversion of food/fuel to monomer building blocks; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolic reactions may be categorized as catabolic—the breaking down of compounds (for example, the breaking down of glucose to pyruvate by cellular respiration); or anabolic—the building up (synthesis) of compounds (such as proteins, carbohydrates, lipids, and nucleic acids). Usually, catabolism releases energy, and anabolism consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, each step being facilitated by a specific enzyme. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts—they allow a reaction to proceed more rapidly without being consumed by it—by reducing the amount of activation energy needed to convert reactants into products. Enzymes also allow the regulation of the rate of a metabolic reaction, for example in response to changes in the cell's environment or to signals from other cells. === Cellular respiration === Cellular respiration is a set of metabolic reactions and processes that take place in cells to convert chemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy. Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction, it clearly does not resemble one when it occurs in a cell because of the slow, controlled release of energy from the series of reactions. Sugar in the form of glucose is the main nutrient used by animal and plant cells in respiration. Cellular respiration involving oxygen is called aerobic respiration, which has four stages: glycolysis, citric acid cycle (or Krebs cycle), electron transport chain, and oxidative phosphorylation. Glycolysis is a metabolic process that occurs in the cytoplasm whereby glucose is converted into two pyruvates, with two net molecules of ATP being produced at the same time. Each pyruvate is then oxidized into acetyl-CoA by the pyruvate dehydrogenase complex, which also generates NADH and carbon dioxide. Acetyl-CoA enters the citric acid cycle, which takes places inside the mitochondrial matrix. At the end of the cycle, the total yield from 1 glucose (or 2 pyruvates) is 6 NADH, 2 FADH2, and 2 ATP molecules. Finally, the next stage is oxidative phosphorylation, which in eukaryotes, occurs in the mitochondrial cristae. Oxidative phosphorylation comprises the electron transport chain, which is a series of four protein complexes that transfer electrons from one complex to another, thereby releasing energy from NADH and FADH2 that is coupled to the pumping of protons (hydrogen ions) across the inner mitochondrial membrane (chemiosmosis), which generates a proton motive force. Energy from the proton motive force drives the enzyme ATP synthase to synthesize more ATPs by phosphorylating ADPs. The transfer of electrons terminates with molecular oxygen being the final electron acceptor. If oxygen were not present, pyruvate would not be metabolized by cellular respiration but undergoes a process of fermentation. The pyruvate is not transported into the mitochondrion but remains in the cytoplasm, where it is converted to waste products that may be removed from the cell. This serves the purpose of oxidizing the electron carriers so that they can perform glycolysis again and removing the excess pyruvate. Fermentation oxidizes NADH to NAD+ so it can be re-used in glycolysis. In the absence of oxygen, fermentation prevents the buildup of NADH in the cytoplasm and provides NAD+ for glycolysis. This waste product varies depending on the organism. In skeletal muscles, the waste product is lactic acid. This type of fermentation is called lactic acid fermentation. In strenuous exercise, when energy demands exceed energy supply, the respiratory chain cannot process all of the hydrogen atoms joined by NADH. During anaerobic glycolysis, NAD+ regenerates when pairs of hydrogen combine with pyruvate to form lactate. Lactate formation is catalyzed by lactate dehydrogenase in a reversible reaction. Lactate can also be used as an indirect precursor for liver glycogen. During recovery, when oxygen becomes available, NAD+ attaches to hydrogen from lactate to form ATP. In yeast, the waste products are ethanol and carbon dioxide. This type of fermentation is known as alcoholic or ethanol fermentation. The ATP generated in this process is made by substrate-level phosphorylation, which does not require oxygen. === Photosynthesis === Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organism's metabolic activities via cellular respiration. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants, algae, and cyanobacteria perform photosynthesis, which is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Photosynthesis has four stages: Light absorption, electron transport, ATP synthesis, and carbon fixation. Light absorption is the initial step of photosynthesis whereby light energy is absorbed by chlorophyll pigments attached to proteins in the thylakoid membranes. The absorbed light energy is used to remove electrons from a donor (water) to a primary electron acceptor, a quinone designated as Q. In the second stage, electrons move from the quinone primary electron acceptor through a series of electron carriers until they reach a final electron acceptor, which is usually the oxidized form of NADP+, which is reduced to NADPH, a process that takes place in a protein complex called photosystem I (PSI). The transport of electrons is coupled to the movement of protons (or hydrogen) from the stroma to the thylakoid membrane, which forms a pH gradient across the membrane as hydrogen becomes more concentrated in the lumen than in the stroma. This is analogous to the proton-motive force generated across the inner mitochondrial membrane in aerobic respiration. During the third stage of photosynthesis, the movement of protons down their concentration gradients from the thylakoid lumen to the stroma through the ATP synthase is coupled to the synthesis of ATP by that same ATP synthase. The NADPH and ATPs generated by the light-dependent reactions in the second and third stages, respectively, provide the energy and electrons to drive the synthesis of glucose by fixing atmospheric carbon dioxide into existing organic carbon compounds, such as ribulose bisphosphate (RuBP) in a sequence of light-independent (or dark) reactions called the Calvin cycle. === Cell signaling === Cell signaling (or communication) is the ability of cells to receive, process, and transmit signals with its environment and with itself. Signals can be non-chemical such as light, electrical impulses, and heat, or chemical signals (or ligands) that interact with receptors, which can be found embedded in the cell membrane of another cell or located deep inside a cell. There are generally four types of chemical signals: autocrine, paracrine, juxtacrine, and hormones. In autocrine signaling, the ligand affects the same cell that releases it. Tumor cells, for example, can reproduce uncontrollably because they release signals that initiate their own self-division. In paracrine signaling, the ligand diffuses to nearby cells and affects them. For example, brain cells called neurons release ligands called neurotransmitters that diffuse across a synaptic cleft to bind with a receptor on an adjacent cell such as another neuron or muscle cell. In juxtacrine signaling, there is direct contact between the signaling and responding cells. Finally, hormones are ligands that travel through the circulatory systems of animals or vascular systems of plants to reach their target cells. Once a ligand binds with a receptor, it can influence the behavior of another cell, depending on the type of receptor. For instance, neurotransmitters that bind with an inotropic receptor can alter the excitability of a target cell. Other types of receptors include protein kinase receptors (e.g., receptor for the hormone insulin) and G protein-coupled receptors. Activation of G protein-coupled receptors can initiate second messenger cascades. The process by which a chemical or physical signal is transmitted through a cell as a series of molecular events is called signal transduction. === Cell cycle === The cell cycle is a series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA and some of its organelles, and the subsequent partitioning of its cytoplasm into two daughter cells in a process called cell division. In eukaryotes (i.e., animal, plant, fungal, and protist cells), there are two distinct types of cell division: mitosis and meiosis. Mitosis is part of the cell cycle, in which replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained. In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA is replicated) and is often followed by telophase and cytokinesis; which divides the cytoplasm, organelles and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components. The different stages of mitosis all together define the mitotic phase of an animal cell cycle—the division of the mother cell into two genetically identical daughter cells. The cell cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. After cell division, each of the daughter cells begin the interphase of a new cycle. In contrast to mitosis, meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the first division (meiosis I), and sister chromatids are separated in the second division (meiosis II). Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor. Prokaryotes (i.e., archaea and bacteria) can also undergo cell division (or binary fission). Unlike the processes of mitosis and meiosis in eukaryotes, binary fission in prokaryotes takes place without the formation of a spindle apparatus on the cell. Before binary fission, DNA in the bacterium is tightly coiled. After it has uncoiled and duplicated, it is pulled to the separate poles of the bacterium as it increases the size to prepare for splitting. Growth of a new cell wall begins to separate the bacterium (triggered by FtsZ polymerization and "Z-ring" formation). The new cell wall (septum) fully develops, resulting in the complete split of the bacterium. The new daughter cells have tightly coiled DNA rods, ribosomes, and plasmids. === Sexual reproduction and meiosis === Meiosis is a central feature of sexual reproduction in eukaryotes, and the most fundamental function of meiosis appears to be conservation of the integrity of the genome that is passed on to progeny by parents. Two aspects of sexual reproduction, meiotic recombination and outcrossing, are likely maintained respectively by the adaptive advantages of recombinational repair of genomic DNA damage and genetic complementation which masks the expression of deleterious recessive mutations. The beneficial effect of genetic complementation, derived from outcrossing (cross-fertilization) is also referred to as hybrid vigor or heterosis. Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom at the start of chapter XII noted “The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented.” Genetic variation, often produced as a byproduct of sexual reproduction, may provide long-term advantages to those sexual lineages that engage in outcrossing. == Genetics == === Inheritance === Genetics is the scientific study of inheritance. Mendelian inheritance, specifically, is the process by which genes and traits are passed on from parents to offspring. It has several principles. The first is that genetic characteristics, alleles, are discrete and have alternate forms (e.g., purple vs. white or tall vs. dwarf), each inherited from one of two parents. Based on the law of dominance and uniformity, which states that some alleles are dominant while others are recessive; an organism with at least one dominant allele will display the phenotype of that dominant allele. During gamete formation, the alleles for each gene segregate, so that each gamete carries only one allele for each gene. Heterozygotic individuals produce gametes with an equal frequency of two alleles. Finally, the law of independent assortment, states that genes of different traits can segregate independently during the formation of gametes, i.e., genes are unlinked. An exception to this rule would include traits that are sex-linked. Test crosses can be performed to experimentally determine the underlying genotype of an organism with a dominant phenotype. A Punnett square can be used to predict the results of a test cross. The chromosome theory of inheritance, which states that genes are found on chromosomes, was supported by Thomas Morgans's experiments with fruit flies, which established the sex linkage between eye color and sex in these insects. === Genes and DNA === A gene is a unit of heredity that corresponds to a region of deoxyribonucleic acid (DNA) that carries genetic information that controls form or function of an organism. DNA is composed of two polynucleotide chains that coil around each other to form a double helix. It is found as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. The set of chromosomes in a cell is collectively known as its genome. In eukaryotes, DNA is mainly in the cell nucleus. In prokaryotes, the DNA is held within the nucleoid. The genetic information is held within genes, and the complete assemblage in an organism is called its genotype. DNA replication is a semiconservative process whereby each strand serves as a template for a new strand of DNA. Mutations are heritable changes in DNA. They can arise spontaneously as a result of replication errors that were not corrected by proofreading or can be induced by an environmental mutagen such as a chemical (e.g., nitrous acid, benzopyrene) or radiation (e.g., x-ray, gamma ray, ultraviolet radiation, particles emitted by unstable isotopes). Mutations can lead to phenotypic effects such as loss-of-function, gain-of-function, and conditional mutations. Some mutations are beneficial, as they are a source of genetic variation for evolution. Others are harmful if they were to result in a loss of function of genes needed for survival. === Gene expression === Gene expression is the molecular process by which a genotype encoded in DNA gives rise to an observable phenotype in the proteins of an organism's body. This process is summarized by the central dogma of molecular biology, which was formulated by Francis Crick in 1958. According to the Central Dogma, genetic information flows from DNA to RNA to protein. There are two gene expression processes: transcription (DNA to RNA) and translation (RNA to protein). === Gene regulation === The regulation of gene expression by environmental factors and during different stages of development can occur at each step of the process such as transcription, RNA splicing, translation, and post-translational modification of a protein. Gene expression can be influenced by positive or negative regulation, depending on which of the two types of regulatory proteins called transcription factors bind to the DNA sequence close to or at a promoter. A cluster of genes that share the same promoter is called an operon, found mainly in prokaryotes and some lower eukaryotes (e.g., Caenorhabditis elegans). In positive regulation of gene expression, the activator is the transcription factor that stimulates transcription when it binds to the sequence near or at the promoter. Negative regulation occurs when another transcription factor called a repressor binds to a DNA sequence called an operator, which is part of an operon, to prevent transcription. Repressors can be inhibited by compounds called inducers (e.g., allolactose), thereby allowing transcription to occur. Specific genes that can be activated by inducers are called inducible genes, in contrast to constitutive genes that are almost constantly active. In contrast to both, structural genes encode proteins that are not involved in gene regulation. In addition to regulatory events involving the promoter, gene expression can also be regulated by epigenetic changes to chromatin, which is a complex of DNA and protein found in eukaryotic cells. === Genes, development, and evolution === Development is the process by which a multicellular organism (plant or animal) goes through a series of changes, starting from a single cell, and taking on various forms that are characteristic of its life cycle. There are four key processes that underlie development: Determination, differentiation, morphogenesis, and growth. Determination sets the developmental fate of a cell, which becomes more restrictive during development. Differentiation is the process by which specialized cells arise from less specialized cells such as stem cells. Stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. Cellular differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals, which are largely due to highly controlled modifications in gene expression and epigenetics. With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence itself. Thus, different cells can have very different physical characteristics despite having the same genome. Morphogenesis, or the development of body form, is the result of spatial differences in gene expression. A small fraction of the genes in an organism's genome called the developmental-genetic toolkit control the development of that organism. These toolkit genes are highly conserved among phyla, meaning that they are ancient and very similar in widely separated groups of animals. Differences in deployment of toolkit genes affect the body plan and the number, identity, and pattern of body parts. Among the most important toolkit genes are the Hox genes. Hox genes determine where repeating parts, such as the many vertebrae of snakes, will grow in a developing embryo or larva. == Evolution == === Evolutionary processes === Evolution is a central organizing concept in biology. It is the change in heritable characteristics of populations over successive generations. In artificial selection, animals were selectively bred for specific traits. Given that traits are inherited, populations contain a varied mix of traits, and reproduction is able to increase any population, Darwin argued that in the natural world, it was nature that played the role of humans in selecting for specific traits. Darwin inferred that individuals who possessed heritable traits better adapted to their environments are more likely to survive and produce more offspring than other individuals. He further inferred that this would lead to the accumulation of favorable traits over successive generations, thereby increasing the match between the organisms and their environment. === Speciation === A species is a group of organisms that mate with one another and speciation is the process by which one lineage splits into two lineages as a result of having evolved independently from each other. For speciation to occur, there has to be reproductive isolation. Reproductive isolation can result from incompatibilities between genes as described by Bateson–Dobzhansky–Muller model. Reproductive isolation also tends to increase with genetic divergence. Speciation can occur when there are physical barriers that divide an ancestral species, a process known as allopatric speciation. === Phylogeny === A phylogeny is an evolutionary history of a specific group of organisms or their genes. It can be represented using a phylogenetic tree, a diagram showing lines of descent among organisms or their genes. Each line drawn on the time axis of a tree represents a lineage of descendants of a particular species or population. When a lineage divides into two, it is represented as a fork or split on the phylogenetic tree. Phylogenetic trees are the basis for comparing and grouping different species. Different species that share a feature inherited from a common ancestor are described as having homologous features (or synapomorphy). Phylogeny provides the basis of biological classification. This classification system is rank-based, with the highest rank being the domain followed by kingdom, phylum, class, order, family, genus, and species. All organisms can be classified as belonging to one of three domains: Archaea (originally Archaebacteria), Bacteria (originally eubacteria), or Eukarya (includes the fungi, plant, and animal kingdoms). === History of life === The history of life on Earth traces how organisms have evolved from the earliest emergence of life to present day. Earth formed about 4.5 billion years ago and all life on Earth, both living and extinct, descended from a last universal common ancestor that lived about 3.5 billion years ago. Geologists have developed a geologic time scale that divides the history of the Earth into major divisions, starting with four eons (Hadean, Archean, Proterozoic, and Phanerozoic), the first three of which are collectively known as the Precambrian, which lasted approximately 4 billion years. Each eon can be divided into eras, with the Phanerozoic eon that began 539 million years ago being subdivided into Paleozoic, Mesozoic, and Cenozoic eras. These three eras together comprise eleven periods (Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Tertiary, and Quaternary). The similarities among all known present-day species indicate that they have diverged through the process of evolution from their common ancestor. Biologists regard the ubiquity of the genetic code as evidence of universal common descent for all bacteria, archaea, and eukaryotes. Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean eon and many of the major steps in early evolution are thought to have taken place in this environment. The earliest evidence of eukaryotes dates from 1.85 billion years ago, and while they may have been present earlier, their diversification accelerated when they started using oxygen in their metabolism. Later, around 1.7 billion years ago, multicellular organisms began to appear, with differentiated cells performing specialised functions. Algae-like multicellular land plants are dated back to about 1 billion years ago, although evidence suggests that microorganisms formed the earliest terrestrial ecosystems, at least 2.7 billion years ago. Microorganisms are thought to have paved the way for the inception of land plants in the Ordovician period. Land plants were so successful that they are thought to have contributed to the Late Devonian extinction event. Ediacara biota appear during the Ediacaran period, while vertebrates, along with most other modern phyla originated about 525 million years ago during the Cambrian explosion. During the Permian period, synapsids, including the ancestors of mammals, dominated the land, but most of this group became extinct in the Permian–Triassic extinction event 252 million years ago. During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates; one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods. After the Cretaceous–Paleogene extinction event 66 million years ago killed off the non-avian dinosaurs, mammals increased rapidly in size and diversity. Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify. == Diversity == === Bacteria and Archaea === Bacteria are a type of cell that constitute a large domain of prokaryotic microorganisms. Typically a few micrometers in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of the Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about 27 percent of the bacterial phyla have species that can be grown in the laboratory. Archaea constitute the other domain of prokaryotic cells and were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), a term that has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat and square cells of Haloquadratum walsbyi. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved in transcription and translation. Other aspects of archaeal biochemistry are unique, such as their reliance on ether lipids in their cell membranes, including archaeols. Archaea use more energy sources than eukaryotes: these range from organic compounds, such as sugars, to ammonia, metal ions or even hydrogen gas. Salt-tolerant archaea (the Haloarchaea) use sunlight as an energy source, and other species of archaea fix carbon, but unlike plants and cyanobacteria, no known species of archaea does both. Archaea reproduce asexually by binary fission, fragmentation, or budding; unlike bacteria, no known species of Archaea form endospores. The first observed archaea were extremophiles, living in extreme environments, such as hot springs and salt lakes with no other organisms. Improved molecular detection tools led to the discovery of archaea in almost every habitat, including soil, oceans, and marshlands. Archaea are particularly numerous in the oceans, and the archaea in plankton may be one of the most abundant groups of organisms on the planet. Archaea are a major part of Earth's life. They are part of the microbiota of all organisms. In the human microbiome, they are important in the gut, mouth, and on the skin. Their morphological, metabolic, and geographical diversity permits them to play multiple ecological roles: carbon fixation; nitrogen cycling; organic compound turnover; and maintaining microbial symbiotic and syntrophic communities, for example. === Eukaryotes === Eukaryotes are hypothesized to have split from archaea, which was followed by their endosymbioses with bacteria (or symbiogenesis) that gave rise to mitochondria and chloroplasts, both of which are now part of modern-day eukaryotic cells. The major lineages of eukaryotes diversified in the Precambrian about 1.5 billion years ago and can be classified into eight major clades: alveolates, excavates, stramenopiles, plants, rhizarians, amoebozoans, fungi, and animals. Five of these clades are collectively known as protists, which are mostly microscopic eukaryotic organisms that are not plants, fungi, or animals. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), protists by themselves do not constitute a separate clade as some protists may be more closely related to plants, fungi, or animals than they are to other protists. Like groupings such as algae, invertebrates, or protozoans, the protist grouping is not a formal taxonomic group but is used for convenience. Most protists are unicellular; these are called microbial eukaryotes. Plants are mainly multicellular organisms, predominantly photosynthetic eukaryotes of the kingdom Plantae, which would exclude fungi and some algae. Plant cells were derived by endosymbiosis of a cyanobacterium into an early eukaryote about one billion years ago, which gave rise to chloroplasts. The first several clades that emerged following primary endosymbiosis were aquatic and most of the aquatic photosynthetic eukaryotic organisms are collectively described as algae, which is a term of convenience as not all algae are closely related. Algae comprise several distinct clades such as glaucophytes, which are microscopic freshwater algae that may have resembled in form to the early unicellular ancestor of Plantae. Unlike glaucophytes, the other algal clades such as red and green algae are multicellular. Green algae comprise three major clades: chlorophytes, coleochaetophytes, and stoneworts. Fungi are eukaryotes that digest foods outside their bodies, secreting digestive enzymes that break down large food molecules before absorbing them through their cell membranes. Many fungi are also saprobes, feeding on dead organic matter, making them important decomposers in ecological systems. Animals are multicellular eukaryotes. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. They have complex interactions with each other and their environments, forming intricate food webs. === Viruses === Viruses are submicroscopic infectious agents that replicate inside the cells of organisms. Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. More than 6,000 virus species have been described in detail. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity in a way analogous to sexual reproduction. Because viruses possess some but not all characteristics of life, they have been described as "organisms at the edge of life", and as self-replicators. == Ecology == Ecology is the study of the distribution and abundance of life, the interaction between organisms and their environment. === Ecosystems === The community of living (biotic) organisms in conjunction with the nonliving (abiotic) components (e.g., water, light, radiation, temperature, humidity, atmosphere, acidity, and soil) of their environment is called an ecosystem. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy from the sun enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals move matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes. === Populations === A population is the group of organisms of the same species that occupies an area and reproduce from generation to generation. Population size can be estimated by multiplying population density by the area or volume. The carrying capacity of an environment is the maximum population size of a species that can be sustained by that specific environment, given the food, habitat, water, and other resources that are available. The carrying capacity of a population can be affected by changing environmental conditions such as changes in the availability of resources and the cost of maintaining them. In human populations, new technologies such as the Green revolution have helped increase the Earth's carrying capacity for humans over time, which has stymied the attempted predictions of impending population decline, the most famous of which was by Thomas Malthus in the 18th century. === Communities === A community is a group of populations of species occupying the same geographical area at the same time. A biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species (intraspecific interactions), or of different species (interspecific interactions). These effects may be short-term, like pollination and predation, or long-term; both often strongly influence the evolution of the species involved. A long-term interaction is called a symbiosis. Symbioses range from mutualism, beneficial to both partners, to competition, harmful to both partners. Every species participates as a consumer, resource, or both in consumer–resource interactions, which form the core of food chains or food webs. There are different trophic levels within any food web, with the lowest level being the primary producers (or autotrophs) such as plants and algae that convert energy and inorganic material into organic compounds, which can then be used by the rest of the community. At the next level are the heterotrophs, which are the species that obtain energy by breaking apart organic compounds from other organisms. Heterotrophs that consume plants are primary consumers (or herbivores) whereas heterotrophs that consume herbivores are secondary consumers (or carnivores). And those that eat secondary consumers are tertiary consumers and so on. Omnivorous heterotrophs are able to consume at multiple levels. Finally, there are decomposers that feed on the waste products or dead bodies of organisms. On average, the total amount of energy incorporated into the biomass of a trophic level per unit of time is about one-tenth of the energy of the trophic level that it consumes. Waste and dead material used by decomposers as well as heat lost from metabolism make up the other ninety percent of energy that is not consumed by the next trophic level. === Biosphere === In the global ecosystem or biosphere, matter exists as different interacting compartments, which can be biotic or abiotic as well as accessible or inaccessible, depending on their forms and locations. For example, matter from terrestrial autotrophs are both biotic and accessible to other organisms whereas the matter in rocks and minerals are abiotic and inaccessible. A biogeochemical cycle is a pathway by which specific elements of matter are turned over or moved through the biotic (biosphere) and the abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth. There are biogeochemical cycles for nitrogen, carbon, and water. === Conservation === Conservation biology is the study of the conservation of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is concerned with factors that influence the maintenance, loss, and restoration of biodiversity and the science of sustaining evolutionary processes that engender genetic, population, species, and ecosystem diversity. The concern stems from estimates suggesting that up to 50% of all species on the planet will disappear within the next 50 years, which has contributed to poverty, starvation, and will reset the course of evolution on this planet. Biodiversity affects the functioning of ecosystems, which provide a variety of services upon which people depend. Conservation biologists research and educate on the trends of biodiversity loss, species extinctions, and the negative effect these are having on our capabilities to sustain the well-being of human society. Organizations and citizens are responding to the current biodiversity crisis through conservation action plans that direct research, monitoring, and education programs that engage concerns at local through global scales. == See also == == References == == Further reading == == External links == OSU's Phylocode Biology Online – Wiki Dictionary MIT video lecture series on biology OneZoom Tree of Life Journal of the History of Biology (springer.com) Journal links PLOS ONE PLOS Biology A peer-reviewed, open-access journal published by the Public Library of Science Current Biology: General journal publishing original research from all areas of biology Biology Letters: A high-impact Royal Society journal publishing peer-reviewed biology papers of general interest Science: Internationally renowned AAAS science journal – see sections of the life sciences International Journal of Biological Sciences: A biological journal publishing significant peer-reviewed scientific papers Perspectives in Biology and Medicine: An interdisciplinary scholarly journal publishing essays of broad relevance
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Science is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. Science is based in Washington, D.C., United States, with a second office in Cambridge, UK. == Contents == The major focus of the journal is publishing important original scientific research and research reviews, but Science also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, Science and its rival Nature cover the full range of scientific disciplines. According to the Journal Citation Reports, Science's 2023 impact factor was 44.7. Studies of methodological quality and reliability have found that some high-prestige journals including Science "publish significantly substandard structures", and overall "reliability of published research works in several fields may be decreasing with increasing journal rank". Although it is the journal of the AAAS, membership in the AAAS is not required to publish in Science. Papers are accepted from authors around the world. Competition to publish in Science is very intense, as an article published in such a highly cited journal can lead to attention and career advancement for the authors. Fewer than 7% of articles submitted are accepted for publication. == History == Science was founded by New York journalist John Michels in 1880 with financial support from Thomas Edison and later from Alexander Graham Bell. (Edison received favorable editorial treatment in return, without disclosure of the financial relationship, at a time when his reputation was suffering due to delays producing the promised commercially viable light bulb.) However, the journal never gained enough subscribers to succeed and ended publication in March 1882. Alexander Graham Bell and Gardiner Greene Hubbard bought the magazine rights and hired young entomologist Samuel H. Scudder to resurrect the journal one year later. They had some success while covering the meetings of prominent American scientific societies, including the AAAS. However, by 1894, Science was again in financial difficulty and was sold to psychologist James McKeen Cattell for $500 (equivalent to $18,170 in 2024). In an agreement worked out by Cattell and AAAS secretary Leland O. Howard, Science became the journal of the American Association for the Advancement of Science in 1900. During the early part of the 20th century, important articles published in Science included papers on fruit fly genetics by Thomas Hunt Morgan, gravitational lensing by Albert Einstein, and spiral nebulae by Edwin Hubble. After Cattell died in 1944, the ownership of the journal was transferred to the AAAS. After Cattell's death in 1944, the journal lacked a consistent editorial presence until Graham DuShane became editor in 1956. In 1958, under DuShane's leadership, Science absorbed The Scientific Monthly, thus increasing the journal's circulation by over 62% from 38,000 to more than 61,000. Physicist Philip Abelson, a co-discoverer of neptunium, served as editor from 1962 to 1984. Under Abelson the efficiency of the review process was improved and the publication practices were brought up to date. During this time, papers on the Apollo program missions and some of the earliest reports on AIDS were published. Biochemist Daniel E. Koshland Jr. served as editor from 1985 until 1995. From 1995 until 2000, neuroscientist Floyd E. Bloom held that position. Biologist Donald Kennedy became the editor of Science in 2000. Biochemist Bruce Alberts took his place in March 2008. Geophysicist Marcia McNutt became editor-in-chief in June 2013. During her tenure the family of journals expanded to include Science Robotics and Science Immunology, and open access publishing with Science Advances. Jeremy M. Berg became editor-in-chief on July 1, 2016. Former Washington University in St. Louis Provost Holden Thorp was named editor-in-chief on Monday, August 19, 2019. In February 2001, draft results of the human genome were simultaneously published by Nature and Science with Science publishing the Celera Genomics paper and Nature publishing the publicly funded Human Genome Project. In 2007, Science (together with Nature) received the Prince of Asturias Award for Communications and Humanity. In 2015, Rush D. Holt Jr., chief executive officer of the AAAS and executive publisher of Science, stated that the journal was becoming increasingly international: "[I]nternationally co-authored papers are now the norm—they represent almost 60 percent of the papers. In 1992, it was slightly less than 20 percent." == Availability == The latest editions of the journal are available online, through the main journal website, only to subscribers, AAAS members, and for delivery to IP addresses at institutions that subscribe; students, K–12 teachers, and some others can subscribe at a reduced fee. However, research articles published after 1997 are available free (with online registration) one year after they are published i.e. delayed open access. Significant public-health related articles are also available free, sometimes immediately after publication. AAAS members may also access the pre-1997 Science archives at the Science website, where it is called "Science Classic". The journal also participates in initiatives that provide free or low-cost access to readers in developing countries, including HINARI, OARE, AGORA, and Scidev.net. Other features of the Science website include the free "ScienceNow" section with "up to the minute news from science", and "ScienceCareers", which provides free career resources for scientists and engineers. Science Express (Sciencexpress) provides advance electronic publication of selected Science papers. == Affiliations == Science received funding for COVID-19-related coverage from the Pulitzer Center and the Heising-Simons Foundation. == See also == AAAS publications Breakthrough of the Year List of scientific journals == References == === AAAS references === == External links == Official website
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https://en.wikipedia.org/wiki/Science_(journal)
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In computer science, an integer is a datum of integral data type, a data type that represents some range of mathematical integers. Integral data types may be of different sizes and may or may not be allowed to contain negative values. Integers are commonly represented in a computer as a group of binary digits (bits). The size of the grouping varies so the set of integer sizes available varies between different types of computers. Computer hardware nearly always provides a way to represent a processor register or memory address as an integer. == Value and representation == The value of an item with an integral type is the mathematical integer that it corresponds to. Integral types may be unsigned (capable of representing only non-negative integers) or signed (capable of representing negative integers as well). An integer value is typically specified in the source code of a program as a sequence of digits optionally prefixed with + or −. Some programming languages allow other notations, such as hexadecimal (base 16) or octal (base 8). Some programming languages also permit digit group separators. The internal representation of this datum is the way the value is stored in the computer's memory. Unlike mathematical integers, a typical datum in a computer has some minimal and maximum possible value. The most common representation of a positive integer is a string of bits, using the binary numeral system. The order of the memory bytes storing the bits varies; see endianness. The width, precision, or bitness of an integral type is the number of bits in its representation. An integral type with n bits can encode 2n numbers; for example an unsigned type typically represents the non-negative values 0 through 2n − 1. Other encodings of integer values to bit patterns are sometimes used, for example binary-coded decimal or Gray code, or as printed character codes such as ASCII. There are four well-known ways to represent signed numbers in a binary computing system. The most common is two's complement, which allows a signed integral type with n bits to represent numbers from −2(n−1) through 2(n−1) − 1. Two's complement arithmetic is convenient because there is a perfect one-to-one correspondence between representations and values (in particular, no separate +0 and −0), and because addition, subtraction and multiplication do not need to distinguish between signed and unsigned types. Other possibilities include offset binary, sign-magnitude, and ones' complement. Some computer languages define integer sizes in a machine-independent way; others have varying definitions depending on the underlying processor word size. Not all language implementations define variables of all integer sizes, and defined sizes may not even be distinct in a particular implementation. An integer in one programming language may be a different size in a different language, on a different processor, or in an execution context of different bitness; see § Words. Some older computer architectures used decimal representations of integers, stored in binary-coded decimal (BCD) or other format. These values generally require data sizes of 4 bits per decimal digit (sometimes called a nibble), usually with additional bits for a sign. Many modern CPUs provide limited support for decimal integers as an extended datatype, providing instructions for converting such values to and from binary values. Depending on the architecture, decimal integers may have fixed sizes (e.g., 7 decimal digits plus a sign fit into a 32-bit word), or may be variable-length (up to some maximum digit size), typically occupying two digits per byte (octet). == Common integral data types == Different CPUs support different integral data types. Typically, hardware will support both signed and unsigned types, but only a small, fixed set of widths. The table above lists integral type widths that are supported in hardware by common processors. High-level programming languages provide more possibilities. It is common to have a 'double width' integral type that has twice as many bits as the biggest hardware-supported type. Many languages also have bit-field types (a specified number of bits, usually constrained to be less than the maximum hardware-supported width) and range types (that can represent only the integers in a specified range). Some languages, such as Lisp, Smalltalk, REXX, Haskell, Python, and Raku, support arbitrary precision integers (also known as infinite precision integers or bignums). Other languages that do not support this concept as a top-level construct may have libraries available to represent very large numbers using arrays of smaller variables, such as Java's BigInteger class or Perl's "bigint" package. These use as much of the computer's memory as is necessary to store the numbers; however, a computer has only a finite amount of storage, so they, too, can only represent a finite subset of the mathematical integers. These schemes support very large numbers; for example one kilobyte of memory could be used to store numbers up to 2466 decimal digits long. A Boolean type is a type that can represent only two values: 0 and 1, usually identified with false and true respectively. This type can be stored in memory using a single bit, but is often given a full byte for convenience of addressing and speed of access. A four-bit quantity is known as a nibble (when eating, being smaller than a bite) or nybble (being a pun on the form of the word byte). One nibble corresponds to one digit in hexadecimal and holds one digit or a sign code in binary-coded decimal. === Bytes and octets === The term byte initially meant 'the smallest addressable unit of memory'. In the past, 5-, 6-, 7-, 8-, and 9-bit bytes have all been used. There have also been computers that could address individual bits ('bit-addressed machine'), or that could only address 16- or 32-bit quantities ('word-addressed machine'). The term byte was usually not used at all in connection with bit- and word-addressed machines. The term octet always refers to an 8-bit quantity. It is mostly used in the field of computer networking, where computers with different byte widths might have to communicate. In modern usage byte almost invariably means eight bits, since all other sizes have fallen into disuse; thus byte has come to be synonymous with octet. === Words === The term 'word' is used for a small group of bits that are handled simultaneously by processors of a particular architecture. The size of a word is thus CPU-specific. Many different word sizes have been used, including 6-, 8-, 12-, 16-, 18-, 24-, 32-, 36-, 39-, 40-, 48-, 60-, and 64-bit. Since it is architectural, the size of a word is usually set by the first CPU in a family, rather than the characteristics of a later compatible CPU. The meanings of terms derived from word, such as longword, doubleword, quadword, and halfword, also vary with the CPU and OS. Practically all new desktop processors are capable of using 64-bit words, though embedded processors with 8- and 16-bit word size are still common. The 36-bit word length was common in the early days of computers. One important cause of non-portability of software is the incorrect assumption that all computers have the same word size as the computer used by the programmer. For example, if a programmer using the C language incorrectly declares as int a variable that will be used to store values greater than 215−1, the program will fail on computers with 16-bit integers. That variable should have been declared as long, which has at least 32 bits on any computer. Programmers may also incorrectly assume that a pointer can be converted to an integer without loss of information, which may work on (some) 32-bit computers, but fail on 64-bit computers with 64-bit pointers and 32-bit integers. This issue is resolved by C99 in stdint.h in the form of intptr_t. The bitness of a program may refer to the word size (or bitness) of the processor on which it runs, or it may refer to the width of a memory address or pointer, which can differ between execution modes or contexts. For example, 64-bit versions of Microsoft Windows support existing 32-bit binaries, and programs compiled for Linux's x32 ABI run in 64-bit mode yet use 32-bit memory addresses. === Standard integer === The standard integer size is platform-dependent. In C, it is denoted by int and required to be at least 16 bits. Windows and Unix systems have 32-bit ints on both 32-bit and 64-bit architectures. === Short integer === A short integer can represent a whole number that may take less storage, while having a smaller range, compared with a standard integer on the same machine. In C, it is denoted by short. It is required to be at least 16 bits, and is often smaller than a standard integer, but this is not required. A conforming program can assume that it can safely store values between −(215−1) and 215−1, but it may not assume that the range is not larger. In Java, a short is always a 16-bit integer. In the Windows API, the datatype SHORT is defined as a 16-bit signed integer on all machines. === Long integer === A long integer can represent a whole integer whose range is greater than or equal to that of a standard integer on the same machine. In C, it is denoted by long. It is required to be at least 32 bits, and may or may not be larger than a standard integer. A conforming program can assume that it can safely store values between −(231−1) and 231−1, but it may not assume that the range is not larger. === Long long === In the C99 version of the C programming language and the C++11 version of C++, a long long type is supported that has double the minimum capacity of the standard long. This type is not supported by compilers that require C code to be compliant with the previous C++ standard, C++03, because the long long type did not exist in C++03. For an ANSI/ISO compliant compiler, the minimum requirements for the specified ranges, that is, −(263−1) to 263−1 for signed and 0 to 264−1 for unsigned, must be fulfilled; however, extending this range is permitted. This can be an issue when exchanging code and data between platforms, or doing direct hardware access. Thus, there are several sets of headers providing platform independent exact width types. The C standard library provides stdint.h; this was introduced in C99 and C++11. == Syntax == Integer literals can be written as regular Arabic numerals, consisting of a sequence of digits and with negation indicated by a minus sign before the value. However, most programming languages disallow use of commas or spaces for digit grouping. Examples of integer literals are: 42 10000 -233000 There are several alternate methods for writing integer literals in many programming languages: Many programming languages, especially those influenced by C, prefix an integer literal with 0X or 0x to represent a hexadecimal value, e.g. 0xDEADBEEF. Other languages may use a different notation, e.g. some assembly languages append an H or h to the end of a hexadecimal value. Perl, Ruby, Java, Julia, D, Go, C#, Rust, Python (starting from version 3.6), and PHP (from version 7.4.0 onwards) allow embedded underscores for clarity, e.g. 10_000_000, and fixed-form Fortran ignores embedded spaces in integer literals. C (starting from C23) and C++ use single quotes for this purpose. In C and C++, a leading zero indicates an octal value, e.g. 0755. This was primarily intended to be used with Unix modes; however, it has been criticized because normal integers may also lead with zero. As such, Python, Ruby, Haskell, and OCaml prefix octal values with 0O or 0o, following the layout used by hexadecimal values. Several languages, including Java, C#, Scala, Python, Ruby, OCaml, C (starting from C23) and C++ can represent binary values by prefixing a number with 0B or 0b. == Extreme values == In many programming languages, there exist predefined constants representing the least and the greatest values representable with a given integer type. Names for these include SmallBASIC: MAXINT Java: java.lang.Integer.MAX_VALUE, java.lang.Integer.MIN_VALUE Corresponding fields exist for the other integer classes in Java. C: INT_MAX, etc. GLib: G_MININT, G_MAXINT, G_MAXUINT, ... Haskell: minBound, maxBound Pascal: MaxInt Python 2: sys.maxint Turing: maxint == See also == Arbitrary-precision arithmetic Binary-coded decimal (BCD) C data types Integer overflow Signed number representations == Notes == == References ==
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https://en.wikipedia.org/wiki/Integer_(computer_science)
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"Unified Science" can refer to any of three related strands in contemporary thought. Belief in the unity of science was a central tenet of logical positivism. Different logical positivists construed this doctrine in several different ways, e.g. as a reductionist thesis, that the objects investigated by the special sciences reduce to the objects of a common, putatively more basic domain of science, usually thought to be physics; as the thesis that all of the theories and results of the various sciences can or ought to be expressed in a common language or "universal slang"; or as the thesis that all the special sciences share a common method. The writings of Edward Haskell and a few associates, seeking to rework science into a single discipline employing a common artificial language. This work culminated in the 1972 publication of Full Circle: The Moral Force of Unified Science. The vast part of the work of Haskell and his contemporaries remains unpublished, however. Timothy Wilken and Anthony Judge have recently revived and extended the insights of Haskell and his coworkers. Unified Science has been a consistent thread since the 1940s in Howard T. Odum's systems ecology and the associated Emergy Synthesis, modeling the "ecosystem": the geochemical, biochemical, and thermodynamic processes of the lithosphere and biosphere. Modeling such earthly processes in this manner requires a science uniting geology, physics, biology, and chemistry (H.T.Odum 1995). With this in mind, Odum developed a common language of science based on electronic schematics, with applications to ecology economic systems in mind (H.T.Odum 1994). == See also == Consilience — the unification of knowledge, e.g. science and the humanities Tree of knowledge system == References == Odum, H.T. 1994. Ecological and General Systems: An Introduction to Systems Ecology. Colorado University Press, Colorado. Odum, H.T. 1995. 'Energy Systems and the Unification of Science', in Hall, C.S. (ed.) Maximum Power: The Ideas and Applications of H.T. Odum. Colorado University Press, Colorado: 365-372. == External links == Future Positive Timothy Wilken's website, including a lot of material and diagrams on Edward Haskell's Unified Science Cardioid Attractor Fundamental to Sustainability - 8 transactional games forming the heart of sustainable relationship Anthony Judge's further development of these ideas
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https://en.wikipedia.org/wiki/Unified_Science
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Mathematics is a field of study that discovers and organizes methods, theories and theorems that are developed and proved for the needs of empirical sciences and mathematics itself. There are many areas of mathematics, which include number theory (the study of numbers), algebra (the study of formulas and related structures), geometry (the study of shapes and spaces that contain them), analysis (the study of continuous changes), and set theory (presently used as a foundation for all mathematics). Mathematics involves the description and manipulation of abstract objects that consist of either abstractions from nature or—in modern mathematics—purely abstract entities that are stipulated to have certain properties, called axioms. Mathematics uses pure reason to prove properties of objects, a proof consisting of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, and—in case of abstraction from nature—some basic properties that are considered true starting points of the theory under consideration. Mathematics is essential in the natural sciences, engineering, medicine, finance, computer science, and the social sciences. Although mathematics is extensively used for modeling phenomena, the fundamental truths of mathematics are independent of any scientific experimentation. Some areas of mathematics, such as statistics and game theory, are developed in close correlation with their applications and are often grouped under applied mathematics. Other areas are developed independently from any application (and are therefore called pure mathematics) but often later find practical applications. Historically, the concept of a proof and its associated mathematical rigour first appeared in Greek mathematics, most notably in Euclid's Elements. Since its beginning, mathematics was primarily divided into geometry and arithmetic (the manipulation of natural numbers and fractions), until the 16th and 17th centuries, when algebra and infinitesimal calculus were introduced as new fields. Since then, the interaction between mathematical innovations and scientific discoveries has led to a correlated increase in the development of both. At the end of the 19th century, the foundational crisis of mathematics led to the systematization of the axiomatic method, which heralded a dramatic increase in the number of mathematical areas and their fields of application. The contemporary Mathematics Subject Classification lists more than sixty first-level areas of mathematics. == Areas of mathematics == Before the Renaissance, mathematics was divided into two main areas: arithmetic, regarding the manipulation of numbers, and geometry, regarding the study of shapes. Some types of pseudoscience, such as numerology and astrology, were not then clearly distinguished from mathematics. During the Renaissance, two more areas appeared. Mathematical notation led to algebra which, roughly speaking, consists of the study and the manipulation of formulas. Calculus, consisting of the two subfields differential calculus and integral calculus, is the study of continuous functions, which model the typically nonlinear relationships between varying quantities, as represented by variables. This division into four main areas—arithmetic, geometry, algebra, and calculus—endured until the end of the 19th century. Areas such as celestial mechanics and solid mechanics were then studied by mathematicians, but now are considered as belonging to physics. The subject of combinatorics has been studied for much of recorded history, yet did not become a separate branch of mathematics until the seventeenth century. At the end of the 19th century, the foundational crisis in mathematics and the resulting systematization of the axiomatic method led to an explosion of new areas of mathematics. The 2020 Mathematics Subject Classification contains no less than sixty-three first-level areas. Some of these areas correspond to the older division, as is true regarding number theory (the modern name for higher arithmetic) and geometry. Several other first-level areas have "geometry" in their names or are otherwise commonly considered part of geometry. Algebra and calculus do not appear as first-level areas but are respectively split into several first-level areas. Other first-level areas emerged during the 20th century or had not previously been considered as mathematics, such as mathematical logic and foundations. === Number theory === Number theory began with the manipulation of numbers, that is, natural numbers ( N ) , {\displaystyle (\mathbb {N} ),} and later expanded to integers ( Z ) {\displaystyle (\mathbb {Z} )} and rational numbers ( Q ) . {\displaystyle (\mathbb {Q} ).} Number theory was once called arithmetic, but nowadays this term is mostly used for numerical calculations. Number theory dates back to ancient Babylon and probably China. Two prominent early number theorists were Euclid of ancient Greece and Diophantus of Alexandria. The modern study of number theory in its abstract form is largely attributed to Pierre de Fermat and Leonhard Euler. The field came to full fruition with the contributions of Adrien-Marie Legendre and Carl Friedrich Gauss. Many easily stated number problems have solutions that require sophisticated methods, often from across mathematics. A prominent example is Fermat's Last Theorem. This conjecture was stated in 1637 by Pierre de Fermat, but it was proved only in 1994 by Andrew Wiles, who used tools including scheme theory from algebraic geometry, category theory, and homological algebra. Another example is Goldbach's conjecture, which asserts that every even integer greater than 2 is the sum of two prime numbers. Stated in 1742 by Christian Goldbach, it remains unproven despite considerable effort. Number theory includes several subareas, including analytic number theory, algebraic number theory, geometry of numbers (method oriented), diophantine equations, and transcendence theory (problem oriented). === Geometry === Geometry is one of the oldest branches of mathematics. It started with empirical recipes concerning shapes, such as lines, angles and circles, which were developed mainly for the needs of surveying and architecture, but has since blossomed out into many other subfields. A fundamental innovation was the ancient Greeks' introduction of the concept of proofs, which require that every assertion must be proved. For example, it is not sufficient to verify by measurement that, say, two lengths are equal; their equality must be proven via reasoning from previously accepted results (theorems) and a few basic statements. The basic statements are not subject to proof because they are self-evident (postulates), or are part of the definition of the subject of study (axioms). This principle, foundational for all mathematics, was first elaborated for geometry, and was systematized by Euclid around 300 BC in his book Elements. The resulting Euclidean geometry is the study of shapes and their arrangements constructed from lines, planes and circles in the Euclidean plane (plane geometry) and the three-dimensional Euclidean space. Euclidean geometry was developed without change of methods or scope until the 17th century, when René Descartes introduced what is now called Cartesian coordinates. This constituted a major change of paradigm: Instead of defining real numbers as lengths of line segments (see number line), it allowed the representation of points using their coordinates, which are numbers. Algebra (and later, calculus) can thus be used to solve geometrical problems. Geometry was split into two new subfields: synthetic geometry, which uses purely geometrical methods, and analytic geometry, which uses coordinates systemically. Analytic geometry allows the study of curves unrelated to circles and lines. Such curves can be defined as the graph of functions, the study of which led to differential geometry. They can also be defined as implicit equations, often polynomial equations (which spawned algebraic geometry). Analytic geometry also makes it possible to consider Euclidean spaces of higher than three dimensions. In the 19th century, mathematicians discovered non-Euclidean geometries, which do not follow the parallel postulate. By questioning that postulate's truth, this discovery has been viewed as joining Russell's paradox in revealing the foundational crisis of mathematics. This aspect of the crisis was solved by systematizing the axiomatic method, and adopting that the truth of the chosen axioms is not a mathematical problem. In turn, the axiomatic method allows for the study of various geometries obtained either by changing the axioms or by considering properties that do not change under specific transformations of the space. Today's subareas of geometry include: Projective geometry, introduced in the 16th century by Girard Desargues, extends Euclidean geometry by adding points at infinity at which parallel lines intersect. This simplifies many aspects of classical geometry by unifying the treatments for intersecting and parallel lines. Affine geometry, the study of properties relative to parallelism and independent from the concept of length. Differential geometry, the study of curves, surfaces, and their generalizations, which are defined using differentiable functions. Manifold theory, the study of shapes that are not necessarily embedded in a larger space. Riemannian geometry, the study of distance properties in curved spaces. Algebraic geometry, the study of curves, surfaces, and their generalizations, which are defined using polynomials. Topology, the study of properties that are kept under continuous deformations. Algebraic topology, the use in topology of algebraic methods, mainly homological algebra. Discrete geometry, the study of finite configurations in geometry. Convex geometry, the study of convex sets, which takes its importance from its applications in optimization. Complex geometry, the geometry obtained by replacing real numbers with complex numbers. === Algebra === Algebra is the art of manipulating equations and formulas. Diophantus (3rd century) and al-Khwarizmi (9th century) were the two main precursors of algebra. Diophantus solved some equations involving unknown natural numbers by deducing new relations until he obtained the solution. Al-Khwarizmi introduced systematic methods for transforming equations, such as moving a term from one side of an equation into the other side. The term algebra is derived from the Arabic word al-jabr meaning 'the reunion of broken parts' that he used for naming one of these methods in the title of his main treatise. Algebra became an area in its own right only with François Viète (1540–1603), who introduced the use of variables for representing unknown or unspecified numbers. Variables allow mathematicians to describe the operations that have to be done on the numbers represented using mathematical formulas. Until the 19th century, algebra consisted mainly of the study of linear equations (presently linear algebra), and polynomial equations in a single unknown, which were called algebraic equations (a term still in use, although it may be ambiguous). During the 19th century, mathematicians began to use variables to represent things other than numbers (such as matrices, modular integers, and geometric transformations), on which generalizations of arithmetic operations are often valid. The concept of algebraic structure addresses this, consisting of a set whose elements are unspecified, of operations acting on the elements of the set, and rules that these operations must follow. The scope of algebra thus grew to include the study of algebraic structures. This object of algebra was called modern algebra or abstract algebra, as established by the influence and works of Emmy Noether, and popularized by Van der Waerden's book Moderne Algebra. Some types of algebraic structures have useful and often fundamental properties, in many areas of mathematics. Their study became autonomous parts of algebra, and include: group theory field theory vector spaces, whose study is essentially the same as linear algebra ring theory commutative algebra, which is the study of commutative rings, includes the study of polynomials, and is a foundational part of algebraic geometry homological algebra Lie algebra and Lie group theory Boolean algebra, which is widely used for the study of the logical structure of computers The study of types of algebraic structures as mathematical objects is the purpose of universal algebra and category theory. The latter applies to every mathematical structure (not only algebraic ones). At its origin, it was introduced, together with homological algebra for allowing the algebraic study of non-algebraic objects such as topological spaces; this particular area of application is called algebraic topology. === Calculus and analysis === Calculus, formerly called infinitesimal calculus, was introduced independently and simultaneously by 17th-century mathematicians Newton and Leibniz. It is fundamentally the study of the relationship of variables that depend on each other. Calculus was expanded in the 18th century by Euler with the introduction of the concept of a function and many other results. Presently, "calculus" refers mainly to the elementary part of this theory, and "analysis" is commonly used for advanced parts. Analysis is further subdivided into real analysis, where variables represent real numbers, and complex analysis, where variables represent complex numbers. Analysis includes many subareas shared by other areas of mathematics which include: Multivariable calculus Functional analysis, where variables represent varying functions Integration, measure theory and potential theory, all strongly related with probability theory on a continuum Ordinary differential equations Partial differential equations Numerical analysis, mainly devoted to the computation on computers of solutions of ordinary and partial differential equations that arise in many applications === Discrete mathematics === Discrete mathematics, broadly speaking, is the study of individual, countable mathematical objects. An example is the set of all integers. Because the objects of study here are discrete, the methods of calculus and mathematical analysis do not directly apply. Algorithms—especially their implementation and computational complexity—play a major role in discrete mathematics. The four color theorem and optimal sphere packing were two major problems of discrete mathematics solved in the second half of the 20th century. The P versus NP problem, which remains open to this day, is also important for discrete mathematics, since its solution would potentially impact a large number of computationally difficult problems. Discrete mathematics includes: Combinatorics, the art of enumerating mathematical objects that satisfy some given constraints. Originally, these objects were elements or subsets of a given set; this has been extended to various objects, which establishes a strong link between combinatorics and other parts of discrete mathematics. For example, discrete geometry includes counting configurations of geometric shapes. Graph theory and hypergraphs Coding theory, including error correcting codes and a part of cryptography Matroid theory Discrete geometry Discrete probability distributions Game theory (although continuous games are also studied, most common games, such as chess and poker are discrete) Discrete optimization, including combinatorial optimization, integer programming, constraint programming === Mathematical logic and set theory === The two subjects of mathematical logic and set theory have belonged to mathematics since the end of the 19th century. Before this period, sets were not considered to be mathematical objects, and logic, although used for mathematical proofs, belonged to philosophy and was not specifically studied by mathematicians. Before Cantor's study of infinite sets, mathematicians were reluctant to consider actually infinite collections, and considered infinity to be the result of endless enumeration. Cantor's work offended many mathematicians not only by considering actually infinite sets but by showing that this implies different sizes of infinity, per Cantor's diagonal argument. This led to the controversy over Cantor's set theory. In the same period, various areas of mathematics concluded the former intuitive definitions of the basic mathematical objects were insufficient for ensuring mathematical rigour. This became the foundational crisis of mathematics. It was eventually solved in mainstream mathematics by systematizing the axiomatic method inside a formalized set theory. Roughly speaking, each mathematical object is defined by the set of all similar objects and the properties that these objects must have. For example, in Peano arithmetic, the natural numbers are defined by "zero is a number", "each number has a unique successor", "each number but zero has a unique predecessor", and some rules of reasoning. This mathematical abstraction from reality is embodied in the modern philosophy of formalism, as founded by David Hilbert around 1910. The "nature" of the objects defined this way is a philosophical problem that mathematicians leave to philosophers, even if many mathematicians have opinions on this nature, and use their opinion—sometimes called "intuition"—to guide their study and proofs. The approach allows considering "logics" (that is, sets of allowed deducing rules), theorems, proofs, etc. as mathematical objects, and to prove theorems about them. For example, Gödel's incompleteness theorems assert, roughly speaking that, in every consistent formal system that contains the natural numbers, there are theorems that are true (that is provable in a stronger system), but not provable inside the system. This approach to the foundations of mathematics was challenged during the first half of the 20th century by mathematicians led by Brouwer, who promoted intuitionistic logic, which explicitly lacks the law of excluded middle. These problems and debates led to a wide expansion of mathematical logic, with subareas such as model theory (modeling some logical theories inside other theories), proof theory, type theory, computability theory and computational complexity theory. Although these aspects of mathematical logic were introduced before the rise of computers, their use in compiler design, formal verification, program analysis, proof assistants and other aspects of computer science, contributed in turn to the expansion of these logical theories. === Statistics and other decision sciences === The field of statistics is a mathematical application that is employed for the collection and processing of data samples, using procedures based on mathematical methods especially probability theory. Statisticians generate data with random sampling or randomized experiments. Statistical theory studies decision problems such as minimizing the risk (expected loss) of a statistical action, such as using a procedure in, for example, parameter estimation, hypothesis testing, and selecting the best. In these traditional areas of mathematical statistics, a statistical-decision problem is formulated by minimizing an objective function, like expected loss or cost, under specific constraints. For example, designing a survey often involves minimizing the cost of estimating a population mean with a given level of confidence. Because of its use of optimization, the mathematical theory of statistics overlaps with other decision sciences, such as operations research, control theory, and mathematical economics. === Computational mathematics === Computational mathematics is the study of mathematical problems that are typically too large for human, numerical capacity. Numerical analysis studies methods for problems in analysis using functional analysis and approximation theory; numerical analysis broadly includes the study of approximation and discretization with special focus on rounding errors. Numerical analysis and, more broadly, scientific computing also study non-analytic topics of mathematical science, especially algorithmic-matrix-and-graph theory. Other areas of computational mathematics include computer algebra and symbolic computation. == History == === Etymology === The word mathematics comes from the Ancient Greek word máthēma (μάθημα), meaning 'something learned, knowledge, mathematics', and the derived expression mathēmatikḗ tékhnē (μαθηματικὴ τέχνη), meaning 'mathematical science'. It entered the English language during the Late Middle English period through French and Latin. Similarly, one of the two main schools of thought in Pythagoreanism was known as the mathēmatikoi (μαθηματικοί)—which at the time meant "learners" rather than "mathematicians" in the modern sense. The Pythagoreans were likely the first to constrain the use of the word to just the study of arithmetic and geometry. By the time of Aristotle (384–322 BC) this meaning was fully established. In Latin and English, until around 1700, the term mathematics more commonly meant "astrology" (or sometimes "astronomy") rather than "mathematics"; the meaning gradually changed to its present one from about 1500 to 1800. This change has resulted in several mistranslations: For example, Saint Augustine's warning that Christians should beware of mathematici, meaning "astrologers", is sometimes mistranslated as a condemnation of mathematicians. The apparent plural form in English goes back to the Latin neuter plural mathematica (Cicero), based on the Greek plural ta mathēmatiká (τὰ μαθηματικά) and means roughly "all things mathematical", although it is plausible that English borrowed only the adjective mathematic(al) and formed the noun mathematics anew, after the pattern of physics and metaphysics, inherited from Greek. In English, the noun mathematics takes a singular verb. It is often shortened to maths or, in North America, math. === Ancient === In addition to recognizing how to count physical objects, prehistoric peoples may have also known how to count abstract quantities, like time—days, seasons, or years. Evidence for more complex mathematics does not appear until around 3000 BC, when the Babylonians and Egyptians began using arithmetic, algebra, and geometry for taxation and other financial calculations, for building and construction, and for astronomy. The oldest mathematical texts from Mesopotamia and Egypt are from 2000 to 1800 BC. Many early texts mention Pythagorean triples and so, by inference, the Pythagorean theorem seems to be the most ancient and widespread mathematical concept after basic arithmetic and geometry. It is in Babylonian mathematics that elementary arithmetic (addition, subtraction, multiplication, and division) first appear in the archaeological record. The Babylonians also possessed a place-value system and used a sexagesimal numeral system which is still in use today for measuring angles and time. In the 6th century BC, Greek mathematics began to emerge as a distinct discipline and some Ancient Greeks such as the Pythagoreans appeared to have considered it a subject in its own right. Around 300 BC, Euclid organized mathematical knowledge by way of postulates and first principles, which evolved into the axiomatic method that is used in mathematics today, consisting of definition, axiom, theorem, and proof. His book, Elements, is widely considered the most successful and influential textbook of all time. The greatest mathematician of antiquity is often held to be Archimedes (c. 287 – c. 212 BC) of Syracuse. He developed formulas for calculating the surface area and volume of solids of revolution and used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, in a manner not too dissimilar from modern calculus. Other notable achievements of Greek mathematics are conic sections (Apollonius of Perga, 3rd century BC), trigonometry (Hipparchus of Nicaea, 2nd century BC), and the beginnings of algebra (Diophantus, 3rd century AD). The Hindu–Arabic numeral system and the rules for the use of its operations, in use throughout the world today, evolved over the course of the first millennium AD in India and were transmitted to the Western world via Islamic mathematics. Other notable developments of Indian mathematics include the modern definition and approximation of sine and cosine, and an early form of infinite series. === Medieval and later === During the Golden Age of Islam, especially during the 9th and 10th centuries, mathematics saw many important innovations building on Greek mathematics. The most notable achievement of Islamic mathematics was the development of algebra. Other achievements of the Islamic period include advances in spherical trigonometry and the addition of the decimal point to the Arabic numeral system. Many notable mathematicians from this period were Persian, such as Al-Khwarizmi, Omar Khayyam and Sharaf al-Dīn al-Ṭūsī. The Greek and Arabic mathematical texts were in turn translated to Latin during the Middle Ages and made available in Europe. During the early modern period, mathematics began to develop at an accelerating pace in Western Europe, with innovations that revolutionized mathematics, such as the introduction of variables and symbolic notation by François Viète (1540–1603), the introduction of logarithms by John Napier in 1614, which greatly simplified numerical calculations, especially for astronomy and marine navigation, the introduction of coordinates by René Descartes (1596–1650) for reducing geometry to algebra, and the development of calculus by Isaac Newton (1643–1727) and Gottfried Leibniz (1646–1716). Leonhard Euler (1707–1783), the most notable mathematician of the 18th century, unified these innovations into a single corpus with a standardized terminology, and completed them with the discovery and the proof of numerous theorems. Perhaps the foremost mathematician of the 19th century was the German mathematician Carl Gauss, who made numerous contributions to fields such as algebra, analysis, differential geometry, matrix theory, number theory, and statistics. In the early 20th century, Kurt Gödel transformed mathematics by publishing his incompleteness theorems, which show in part that any consistent axiomatic system—if powerful enough to describe arithmetic—will contain true propositions that cannot be proved. Mathematics has since been greatly extended, and there has been a fruitful interaction between mathematics and science, to the benefit of both. Mathematical discoveries continue to be made to this very day. According to Mikhail B. Sevryuk, in the January 2006 issue of the Bulletin of the American Mathematical Society, "The number of papers and books included in the Mathematical Reviews (MR) database since 1940 (the first year of operation of MR) is now more than 1.9 million, and more than 75 thousand items are added to the database each year. The overwhelming majority of works in this ocean contain new mathematical theorems and their proofs." == Symbolic notation and terminology == Mathematical notation is widely used in science and engineering for representing complex concepts and properties in a concise, unambiguous, and accurate way. This notation consists of symbols used for representing operations, unspecified numbers, relations and any other mathematical objects, and then assembling them into expressions and formulas. More precisely, numbers and other mathematical objects are represented by symbols called variables, which are generally Latin or Greek letters, and often include subscripts. Operation and relations are generally represented by specific symbols or glyphs, such as + (plus), × (multiplication), ∫ {\textstyle \int } (integral), = (equal), and < (less than). All these symbols are generally grouped according to specific rules to form expressions and formulas. Normally, expressions and formulas do not appear alone, but are included in sentences of the current language, where expressions play the role of noun phrases and formulas play the role of clauses. Mathematics has developed a rich terminology covering a broad range of fields that study the properties of various abstract, idealized objects and how they interact. It is based on rigorous definitions that provide a standard foundation for communication. An axiom or postulate is a mathematical statement that is taken to be true without need of proof. If a mathematical statement has yet to be proven (or disproven), it is termed a conjecture. Through a series of rigorous arguments employing deductive reasoning, a statement that is proven to be true becomes a theorem. A specialized theorem that is mainly used to prove another theorem is called a lemma. A proven instance that forms part of a more general finding is termed a corollary. Numerous technical terms used in mathematics are neologisms, such as polynomial and homeomorphism. Other technical terms are words of the common language that are used in an accurate meaning that may differ slightly from their common meaning. For example, in mathematics, "or" means "one, the other or both", while, in common language, it is either ambiguous or means "one or the other but not both" (in mathematics, the latter is called "exclusive or"). Finally, many mathematical terms are common words that are used with a completely different meaning. This may lead to sentences that are correct and true mathematical assertions, but appear to be nonsense to people who do not have the required background. For example, "every free module is flat" and "a field is always a ring". == Relationship with sciences == Mathematics is used in most sciences for modeling phenomena, which then allows predictions to be made from experimental laws. The independence of mathematical truth from any experimentation implies that the accuracy of such predictions depends only on the adequacy of the model. Inaccurate predictions, rather than being caused by invalid mathematical concepts, imply the need to change the mathematical model used. For example, the perihelion precession of Mercury could only be explained after the emergence of Einstein's general relativity, which replaced Newton's law of gravitation as a better mathematical model. There is still a philosophical debate whether mathematics is a science. However, in practice, mathematicians are typically grouped with scientists, and mathematics shares much in common with the physical sciences. Like them, it is falsifiable, which means in mathematics that, if a result or a theory is wrong, this can be proved by providing a counterexample. Similarly as in science, theories and results (theorems) are often obtained from experimentation. In mathematics, the experimentation may consist of computation on selected examples or of the study of figures or other representations of mathematical objects (often mind representations without physical support). For example, when asked how he came about his theorems, Gauss once replied "durch planmässiges Tattonieren" (through systematic experimentation). However, some authors emphasize that mathematics differs from the modern notion of science by not relying on empirical evidence. === Pure and applied mathematics === Until the 19th century, the development of mathematics in the West was mainly motivated by the needs of technology and science, and there was no clear distinction between pure and applied mathematics. For example, the natural numbers and arithmetic were introduced for the need of counting, and geometry was motivated by surveying, architecture and astronomy. Later, Isaac Newton introduced infinitesimal calculus for explaining the movement of the planets with his law of gravitation. Moreover, most mathematicians were also scientists, and many scientists were also mathematicians. However, a notable exception occurred with the tradition of pure mathematics in Ancient Greece. The problem of integer factorization, for example, which goes back to Euclid in 300 BC, had no practical application before its use in the RSA cryptosystem, now widely used for the security of computer networks. In the 19th century, mathematicians such as Karl Weierstrass and Richard Dedekind increasingly focused their research on internal problems, that is, pure mathematics. This led to split mathematics into pure mathematics and applied mathematics, the latter being often considered as having a lower value among mathematical purists. However, the lines between the two are frequently blurred. The aftermath of World War II led to a surge in the development of applied mathematics in the US and elsewhere. Many of the theories developed for applications were found interesting from the point of view of pure mathematics, and many results of pure mathematics were shown to have applications outside mathematics; in turn, the study of these applications may give new insights on the "pure theory". An example of the first case is the theory of distributions, introduced by Laurent Schwartz for validating computations done in quantum mechanics, which became immediately an important tool of (pure) mathematical analysis. An example of the second case is the decidability of the first-order theory of the real numbers, a problem of pure mathematics that was proved true by Alfred Tarski, with an algorithm that is impossible to implement because of a computational complexity that is much too high. For getting an algorithm that can be implemented and can solve systems of polynomial equations and inequalities, George Collins introduced the cylindrical algebraic decomposition that became a fundamental tool in real algebraic geometry. In the present day, the distinction between pure and applied mathematics is more a question of personal research aim of mathematicians than a division of mathematics into broad areas. The Mathematics Subject Classification has a section for "general applied mathematics" but does not mention "pure mathematics". However, these terms are still used in names of some university departments, such as at the Faculty of Mathematics at the University of Cambridge. === Unreasonable effectiveness === The unreasonable effectiveness of mathematics is a phenomenon that was named and first made explicit by physicist Eugene Wigner. It is the fact that many mathematical theories (even the "purest") have applications outside their initial object. These applications may be completely outside their initial area of mathematics, and may concern physical phenomena that were completely unknown when the mathematical theory was introduced. Examples of unexpected applications of mathematical theories can be found in many areas of mathematics. A notable example is the prime factorization of natural numbers that was discovered more than 2,000 years before its common use for secure internet communications through the RSA cryptosystem. A second historical example is the theory of ellipses. They were studied by the ancient Greek mathematicians as conic sections (that is, intersections of cones with planes). It was almost 2,000 years later that Johannes Kepler discovered that the trajectories of the planets are ellipses. In the 19th century, the internal development of geometry (pure mathematics) led to definition and study of non-Euclidean geometries, spaces of dimension higher than three and manifolds. At this time, these concepts seemed totally disconnected from the physical reality, but at the beginning of the 20th century, Albert Einstein developed the theory of relativity that uses fundamentally these concepts. In particular, spacetime of special relativity is a non-Euclidean space of dimension four, and spacetime of general relativity is a (curved) manifold of dimension four. A striking aspect of the interaction between mathematics and physics is when mathematics drives research in physics. This is illustrated by the discoveries of the positron and the baryon Ω − . {\displaystyle \Omega ^{-}.} In both cases, the equations of the theories had unexplained solutions, which led to conjecture of the existence of an unknown particle, and the search for these particles. In both cases, these particles were discovered a few years later by specific experiments. === Specific sciences === ==== Physics ==== Mathematics and physics have influenced each other over their modern history. Modern physics uses mathematics abundantly, and is also considered to be the motivation of major mathematical developments. ==== Computing ==== Computing is closely related to mathematics in several ways. Theoretical computer science is considered to be mathematical in nature. Communication technologies apply branches of mathematics that may be very old (e.g., arithmetic), especially with respect to transmission security, in cryptography and coding theory. Discrete mathematics is useful in many areas of computer science, such as complexity theory, information theory, and graph theory. In 1998, the Kepler conjecture on sphere packing seemed to also be partially proven by computer. ==== Biology and chemistry ==== Biology uses probability extensively in fields such as ecology or neurobiology. Most discussion of probability centers on the concept of evolutionary fitness. Ecology heavily uses modeling to simulate population dynamics, study ecosystems such as the predator-prey model, measure pollution diffusion, or to assess climate change. The dynamics of a population can be modeled by coupled differential equations, such as the Lotka–Volterra equations. Statistical hypothesis testing, is run on data from clinical trials to determine whether a new treatment works. Since the start of the 20th century, chemistry has used computing to model molecules in three dimensions. ==== Earth sciences ==== Structural geology and climatology use probabilistic models to predict the risk of natural catastrophes. Similarly, meteorology, oceanography, and planetology also use mathematics due to their heavy use of models. ==== Social sciences ==== Areas of mathematics used in the social sciences include probability/statistics and differential equations. These are used in linguistics, economics, sociology, and psychology. Often the fundamental postulate of mathematical economics is that of the rational individual actor – Homo economicus (lit. 'economic man'). In this model, the individual seeks to maximize their self-interest, and always makes optimal choices using perfect information. This atomistic view of economics allows it to relatively easily mathematize its thinking, because individual calculations are transposed into mathematical calculations. Such mathematical modeling allows one to probe economic mechanisms. Some reject or criticise the concept of Homo economicus. Economists note that real people have limited information, make poor choices and care about fairness, altruism, not just personal gain. Without mathematical modeling, it is hard to go beyond statistical observations or untestable speculation. Mathematical modeling allows economists to create structured frameworks to test hypotheses and analyze complex interactions. Models provide clarity and precision, enabling the translation of theoretical concepts into quantifiable predictions that can be tested against real-world data. At the start of the 20th century, there was a development to express historical movements in formulas. In 1922, Nikolai Kondratiev discerned the ~50-year-long Kondratiev cycle, which explains phases of economic growth or crisis. Towards the end of the 19th century, mathematicians extended their analysis into geopolitics. Peter Turchin developed cliodynamics since the 1990s. Mathematization of the social sciences is not without risk. In the controversial book Fashionable Nonsense (1997), Sokal and Bricmont denounced the unfounded or abusive use of scientific terminology, particularly from mathematics or physics, in the social sciences. The study of complex systems (evolution of unemployment, business capital, demographic evolution of a population, etc.) uses mathematical knowledge. However, the choice of counting criteria, particularly for unemployment, or of models, can be subject to controversy. == Philosophy == === Reality === The connection between mathematics and material reality has led to philosophical debates since at least the time of Pythagoras. The ancient philosopher Plato argued that abstractions that reflect material reality have themselves a reality that exists outside space and time. As a result, the philosophical view that mathematical objects somehow exist on their own in abstraction is often referred to as Platonism. Independently of their possible philosophical opinions, modern mathematicians may be generally considered as Platonists, since they think of and talk of their objects of study as real objects. Armand Borel summarized this view of mathematics reality as follows, and provided quotations of G. H. Hardy, Charles Hermite, Henri Poincaré and Albert Einstein that support his views. Something becomes objective (as opposed to "subjective") as soon as we are convinced that it exists in the minds of others in the same form as it does in ours and that we can think about it and discuss it together. Because the language of mathematics is so precise, it is ideally suited to defining concepts for which such a consensus exists. In my opinion, that is sufficient to provide us with a feeling of an objective existence, of a reality of mathematics ... Nevertheless, Platonism and the concurrent views on abstraction do not explain the unreasonable effectiveness of mathematics (as Platonism assumes mathematics exists independently, but does not explain why it matches reality). === Proposed definitions === There is no general consensus about the definition of mathematics or its epistemological status—that is, its place inside knowledge. A great many professional mathematicians take no interest in a definition of mathematics, or consider it undefinable. There is not even consensus on whether mathematics is an art or a science. Some just say, "mathematics is what mathematicians do". A common approach is to define mathematics by its object of study. Aristotle defined mathematics as "the science of quantity" and this definition prevailed until the 18th century. However, Aristotle also noted a focus on quantity alone may not distinguish mathematics from sciences like physics; in his view, abstraction and studying quantity as a property "separable in thought" from real instances set mathematics apart. In the 19th century, when mathematicians began to address topics—such as infinite sets—which have no clear-cut relation to physical reality, a variety of new definitions were given. With the large number of new areas of mathematics that have appeared since the beginning of the 20th century, defining mathematics by its object of study has become increasingly difficult. For example, in lieu of a definition, Saunders Mac Lane in Mathematics, form and function summarizes the basics of several areas of mathematics, emphasizing their inter-connectedness, and observes: the development of Mathematics provides a tightly connected network of formal rules, concepts, and systems. Nodes of this network are closely bound to procedures useful in human activities and to questions arising in science. The transition from activities to the formal Mathematical systems is guided by a variety of general insights and ideas. Another approach for defining mathematics is to use its methods. For example, an area of study is often qualified as mathematics as soon as one can prove theorems—assertions whose validity relies on a proof, that is, a purely-logical deduction. === Rigor === Mathematical reasoning requires rigor. This means that the definitions must be absolutely unambiguous and the proofs must be reducible to a succession of applications of inference rules, without any use of empirical evidence and intuition. Rigorous reasoning is not specific to mathematics, but, in mathematics, the standard of rigor is much higher than elsewhere. Despite mathematics' concision, rigorous proofs can require hundreds of pages to express, such as the 255-page Feit–Thompson theorem. The emergence of computer-assisted proofs has allowed proof lengths to further expand. The result of this trend is a philosophy of the quasi-empiricist proof that can not be considered infallible, but has a probability attached to it. The concept of rigor in mathematics dates back to ancient Greece, where their society encouraged logical, deductive reasoning. However, this rigorous approach would tend to discourage exploration of new approaches, such as irrational numbers and concepts of infinity. The method of demonstrating rigorous proof was enhanced in the sixteenth century through the use of symbolic notation. In the 18th century, social transition led to mathematicians earning their keep through teaching, which led to more careful thinking about the underlying concepts of mathematics. This produced more rigorous approaches, while transitioning from geometric methods to algebraic and then arithmetic proofs. At the end of the 19th century, it appeared that the definitions of the basic concepts of mathematics were not accurate enough for avoiding paradoxes (non-Euclidean geometries and Weierstrass function) and contradictions (Russell's paradox). This was solved by the inclusion of axioms with the apodictic inference rules of mathematical theories; the re-introduction of axiomatic method pioneered by the ancient Greeks. It results that "rigor" is no more a relevant concept in mathematics, as a proof is either correct or erroneous, and a "rigorous proof" is simply a pleonasm. Where a special concept of rigor comes into play is in the socialized aspects of a proof, wherein it may be demonstrably refuted by other mathematicians. After a proof has been accepted for many years or even decades, it can then be considered as reliable. Nevertheless, the concept of "rigor" may remain useful for teaching to beginners what is a mathematical proof. == Training and practice == === Education === Mathematics has a remarkable ability to cross cultural boundaries and time periods. As a human activity, the practice of mathematics has a social side, which includes education, careers, recognition, popularization, and so on. In education, mathematics is a core part of the curriculum and forms an important element of the STEM academic disciplines. Prominent careers for professional mathematicians include mathematics teacher or professor, statistician, actuary, financial analyst, economist, accountant, commodity trader, or computer consultant. Archaeological evidence shows that instruction in mathematics occurred as early as the second millennium BCE in ancient Babylonia. Comparable evidence has been unearthed for scribal mathematics training in the ancient Near East and then for the Greco-Roman world starting around 300 BCE. The oldest known mathematics textbook is the Rhind papyrus, dated from c. 1650 BCE in Egypt. Due to a scarcity of books, mathematical teachings in ancient India were communicated using memorized oral tradition since the Vedic period (c. 1500 – c. 500 BCE). In Imperial China during the Tang dynasty (618–907 CE), a mathematics curriculum was adopted for the civil service exam to join the state bureaucracy. Following the Dark Ages, mathematics education in Europe was provided by religious schools as part of the Quadrivium. Formal instruction in pedagogy began with Jesuit schools in the 16th and 17th century. Most mathematical curricula remained at a basic and practical level until the nineteenth century, when it began to flourish in France and Germany. The oldest journal addressing instruction in mathematics was L'Enseignement Mathématique, which began publication in 1899. The Western advancements in science and technology led to the establishment of centralized education systems in many nation-states, with mathematics as a core component—initially for its military applications. While the content of courses varies, in the present day nearly all countries teach mathematics to students for significant amounts of time. During school, mathematical capabilities and positive expectations have a strong association with career interest in the field. Extrinsic factors such as feedback motivation by teachers, parents, and peer groups can influence the level of interest in mathematics. Some students studying mathematics may develop an apprehension or fear about their performance in the subject. This is known as mathematical anxiety, and is considered the most prominent of the disorders impacting academic performance. Mathematical anxiety can develop due to various factors such as parental and teacher attitudes, social stereotypes, and personal traits. Help to counteract the anxiety can come from changes in instructional approaches, by interactions with parents and teachers, and by tailored treatments for the individual. === Psychology (aesthetic, creativity and intuition) === The validity of a mathematical theorem relies only on the rigor of its proof, which could theoretically be done automatically by a computer program. This does not mean that there is no place for creativity in a mathematical work. On the contrary, many important mathematical results (theorems) are solutions of problems that other mathematicians failed to solve, and the invention of a way for solving them may be a fundamental way of the solving process. An extreme example is Apery's theorem: Roger Apery provided only the ideas for a proof, and the formal proof was given only several months later by three other mathematicians. Creativity and rigor are not the only psychological aspects of the activity of mathematicians. Some mathematicians can see their activity as a game, more specifically as solving puzzles. This aspect of mathematical activity is emphasized in recreational mathematics. Mathematicians can find an aesthetic value to mathematics. Like beauty, it is hard to define, it is commonly related to elegance, which involves qualities like simplicity, symmetry, completeness, and generality. G. H. Hardy in A Mathematician's Apology expressed the belief that the aesthetic considerations are, in themselves, sufficient to justify the study of pure mathematics. He also identified other criteria such as significance, unexpectedness, and inevitability, which contribute to mathematical aesthetics. Paul Erdős expressed this sentiment more ironically by speaking of "The Book", a supposed divine collection of the most beautiful proofs. The 1998 book Proofs from THE BOOK, inspired by Erdős, is a collection of particularly succinct and revelatory mathematical arguments. Some examples of particularly elegant results included are Euclid's proof that there are infinitely many prime numbers and the fast Fourier transform for harmonic analysis. Some feel that to consider mathematics a science is to downplay its artistry and history in the seven traditional liberal arts. One way this difference of viewpoint plays out is in the philosophical debate as to whether mathematical results are created (as in art) or discovered (as in science). The popularity of recreational mathematics is another sign of the pleasure many find in solving mathematical questions. == Cultural impact == === Artistic expression === Notes that sound well together to a Western ear are sounds whose fundamental frequencies of vibration are in simple ratios. For example, an octave doubles the frequency and a perfect fifth multiplies it by 3 2 {\displaystyle {\frac {3}{2}}} . Humans, as well as some other animals, find symmetric patterns to be more beautiful. Mathematically, the symmetries of an object form a group known as the symmetry group. For example, the group underlying mirror symmetry is the cyclic group of two elements, Z / 2 Z {\displaystyle \mathbb {Z} /2\mathbb {Z} } . A Rorschach test is a figure invariant by this symmetry, as are butterfly and animal bodies more generally (at least on the surface). Waves on the sea surface possess translation symmetry: moving one's viewpoint by the distance between wave crests does not change one's view of the sea. Fractals possess self-similarity. === Popularization === Popular mathematics is the act of presenting mathematics without technical terms. Presenting mathematics may be hard since the general public suffers from mathematical anxiety and mathematical objects are highly abstract. However, popular mathematics writing can overcome this by using applications or cultural links. Despite this, mathematics is rarely the topic of popularization in printed or televised media. === Awards and prize problems === The most prestigious award in mathematics is the Fields Medal, established in 1936 and awarded every four years (except around World War II) to up to four individuals. It is considered the mathematical equivalent of the Nobel Prize. Other prestigious mathematics awards include: The Abel Prize, instituted in 2002 and first awarded in 2003 The Chern Medal for lifetime achievement, introduced in 2009 and first awarded in 2010 The AMS Leroy P. Steele Prize, awarded since 1970 The Wolf Prize in Mathematics, also for lifetime achievement, instituted in 1978 A famous list of 23 open problems, called "Hilbert's problems", was compiled in 1900 by German mathematician David Hilbert. This list has achieved great celebrity among mathematicians, and at least thirteen of the problems (depending how some are interpreted) have been solved. A new list of seven important problems, titled the "Millennium Prize Problems", was published in 2000. Only one of them, the Riemann hypothesis, duplicates one of Hilbert's problems. A solution to any of these problems carries a 1 million dollar reward. To date, only one of these problems, the Poincaré conjecture, has been solved by the Russian mathematician Grigori Perelman. == See also == == Notes == == References == === Citations === === Other sources === == Further reading ==
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https://en.wikipedia.org/wiki/Mathematics
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In computer science, thrashing occurs in a system with virtual memory when a computer's real storage resources are overcommitted, leading to a constant state of paging and page faults, slowing most application-level processing. This causes the performance of the computer to degrade or even collapse. The situation can continue indefinitely until the user closes some running applications or the active processes free up additional virtual memory resources. After initialization, most programs operate on a small number of code and data pages compared to the total memory the program requires. The pages most frequently accessed at any point are called the working set, which may change over time. When the working set is not significantly greater than the system's total number of real storage page frames, virtual memory systems work most efficiently, and an insignificant amount of computing is spent resolving page faults. As the total of the working sets grows, resolving page faults remains manageable until the growth reaches a critical point at which the number of faults increases dramatically and the time spent resolving them overwhelms the time spent on the computing the program was written to do. This condition is referred to as thrashing. Thrashing may occur on a program that randomly accesses huge data structures, as its large working set causes continual page faults that drastically slow down the system. Satisfying page faults may require freeing pages that will soon have to be re-read from disk. The term is also used for various similar phenomena, particularly movement between other levels of the memory hierarchy, wherein a process progresses slowly because significant time is being spent acquiring resources. "Thrashing" is also used in contexts other than virtual memory systems –for example, to describe cache issues in computing, or silly window syndrome in networking. == Overview == Virtual memory works by treating a portion of secondary storage such as a computer hard disk as an additional layer of the cache hierarchy. Virtual memory allows processes to use more memory than is physically present in main memory. Operating systems supporting virtual memory assign processes a virtual address space and each process refers to addresses in its execution context by a so-called virtual address. To access data such as code or variables at that address, the process must translate the address to a physical address in a process known as virtual address translation. In effect, physical main memory becomes a cache for virtual memory, which is in general stored on disk in memory pages. Programs are allocated a certain number of pages as needed by the operating system. Active memory pages exist in both RAM and on disk. Inactive pages are removed from the cache and written to disk when the main memory becomes full. If processes are utilizing all main memory and need additional memory pages, a cascade of severe cache misses known as page faults will occur, often leading to a noticeable lag in the operating system responsiveness. This process together with the futile, repetitive page swapping that occurs is known as "thrashing". This frequently leads to high, runaway CPU utilization that can grind the system to a halt. In modern computers, thrashing may occur in the paging system (if there is not sufficient physical memory or the disk access time is overly long), or in the I/O communications subsystem (especially in conflicts over internal bus access), etc. Depending on the configuration and algorithms involved, the throughput and latency of a system may degrade by multiple orders of magnitude. Thrashing is when the CPU performs 'productive' work less and 'swapping' work more. The overall memory access time may increase since the higher level memory is only as fast as the next lower level in the memory hierarchy. The CPU is busy swapping pages so much that it cannot respond to users' programs and interrupts as much as required. Thrashing occurs when there are too many pages in memory, and each page refers to another page. Real memory reduces its capacity to contain all the pages, so it uses 'virtual memory'. When each page in execution demands that page that is not currently in real memory (RAM) it places some pages on virtual memory and adjusts the required page on RAM. If the CPU is too busy doing this task, thrashing occurs. === Causes === In virtual memory systems, thrashing may be caused by programs or workloads that present insufficient locality of reference: if the working set of a program or a workload cannot be effectively held within physical memory, then constant data swapping, i.e., thrashing, may occur. The term was first used during the tape operating system days to describe the sound the tapes made when data was being rapidly written to and read. A worst case might occur on VAX processors. A single MOVL crossing a page boundary could have a source operand using a displacement deferred addressing mode, where the longword containing the operand address crosses a page boundary, and a destination operand using a displacement deferred addressing mode, where the longword containing the operand address crosses a page boundary, and the source and destination could both cross page boundaries. This single instruction references ten pages; if not all are in RAM, each will cause a page fault. The total number of pages thus involved in this particular instruction is ten, and all ten pages must be simultaneously present in memory. If any one of the ten pages cannot be swapped in (for example to make room for any of the other pages), the instruction will fault, and every attempt to restart it will fail until all ten pages can be swapped in. A system thrashing is often a result of a sudden spike in page demand from a small number of running programs. Swap-token is a lightweight and dynamic thrashing protection mechanism. The basic idea is to set a token in the system, which is randomly given to a process that has page faults when thrashing happens. The process that has the token is given a privilege to allocate more physical memory pages to build its working set, which is expected to quickly finish its execution and release the memory pages to other processes. A timestamp is used to hand over the tokens one by one. The first version of swap-token is implemented in Linux. The second version is called preempt swap-token. In this updated swap-token implementation, a priority counter is set for each process to track the number of swap-out pages. The token is always given to the process with a high priority, which has a high number of swap-out pages. The length of the time stamp is not a constant but is determined by the priority: the higher the number of swap-out pages of a process, the longer the time stamp for it will be. == Other uses == Thrashing is best known in the context of memory and storage, but analogous phenomena occur for other resources, including: Cache thrashing Where main memory is accessed in a pattern that leads to multiple main memory locations competing for the same cache lines, resulting in excessive cache misses. This is most likely to be problematic for caches with associativity. TLB thrashing Where the translation lookaside buffer (TLB) acting as a cache for the memory management unit (MMU) which translates virtual addresses to physical addresses is too small for the working set of pages. TLB thrashing can occur even if instruction cache or data cache thrashing is not occurring because these are cached in different sizes. Instructions and data are cached in small blocks (cache lines), not entire pages, but address lookup is done at the page level. Thus even if the code and data working sets fit into the cache, if the working sets are fragmented across many pages, the virtual address working set may not fit into TLB, causing TLB thrashing. Heap thrashing Frequent garbage collection, due to failure to allocate memory for an object, due to insufficient free memory or insufficient contiguous free memory due to memory fragmentation is referred to as heap thrashing. Process thrashing A similar phenomenon occurs for processes: when the process working set cannot be coscheduled, i.e. such that not all interacting processes are scheduled to run at the same time, they experience "process thrashing" due to being repeatedly scheduled and unscheduled, progressing only slowly. == See also == Page replacement algorithm – Algorithm for virtual memory implementation Congestion collapse – Reduced quality of service due to high network trafficPages displaying short descriptions of redirect targets Resource contention – In computing, a conflict over access to a shared resource Out of memory – State of computer operation where no additional memory can be allocated Software aging – Tendency of software to fail due to external changes or prolonged operation == References ==
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https://en.wikipedia.org/wiki/Thrashing_(computer_science)
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Speculative fiction is an umbrella genre of fiction that encompasses all the subgenres that depart from realism, or strictly imitating everyday reality, instead presenting fantastical, supernatural, futuristic, or other imaginative realms. This catch-all genre includes, but is not limited to: fantasy, science fiction, science fantasy, superhero, paranormal, supernatural, horror, alternate history, magical realism, slipstream, weird fiction, utopia and dystopia, apocalyptic and post-apocalyptic fiction. In other words, the genre speculates on individuals, events, or places beyond the ordinary real world. The term speculative fiction has been used for works of literature, film, television, drama, video games, radio, and hybrid media. == Speculative versus realistic fiction == The umbrella genre of speculative fiction is characterized by a lesser degree of adherence to plausible depictions of individuals, events, or places, while the umbrella genre of realistic fiction (partly crossing over with literary realism) is characterized by a greater degree of adherence to such depictions. For instance, speculative fiction may depict an entirely imaginary universe or one in which the laws of nature do not strictly apply (often the subgenre of fantasy). Alternatively, the genre depicts actual historical moments, except that they have concluded in an entirely imaginary way or been followed by major imaginary events (i.e., the subgenre of alternative history). As another alternative, the genre depicts impossible technology or technology that defies current scientific understanding or capabilities (i.e., the subgenre of science fiction). By contrast, realistic fiction involves a story whose basic setting is real and whose events could plausibly occur in the real world. One realistic fiction subgenre is historical fiction, which is centred around actual major events and time periods of the past. The attempt to make stories seem faithful to reality or to more objectively describe details—and also the 19th-century artistic movement that vigorously promoted this approach—is called "literary realism"; this includes both fiction and non-fiction works. === Distinguishing science fiction from other speculative fiction === "Speculative fiction" is sometimes abbreviated as spec-fic, spec fic, specfic, S-F, SF, or sf. The last three abbreviations, however, are ambiguous since they have long been used to refer to science fiction (which lies within this general area of literature). The genre is sometimes known as the fantastic or fantastika; the latter term is attributed to science fiction scholar John Clute, who coined it in 2007 after the term for the genre in some Slavic languages. The term speculative fiction has been used by some critics and writers who oppose a perceived limitation of science fiction: the requirement for a story to adhere to scientific principles. These people argue that speculative fiction better defines an expanded, open, imaginative type of fiction than does genre fiction, and the categories of fantasy, mystery, horror and science fiction. Harlan Ellison used the term to avoid being classified as a science fiction writer. Ellison, a fervent proponent of writers embracing more literary and modernist directions, broke out of genre conventions to push the boundaries of speculative fiction. The term suppositional fiction is sometimes used as a subcategory designating fiction in which characters and stories are constrained by an internally consistent world, but not necessarily one defined by any particular genre. == History == Speculative fiction as a category ranges from ancient works to paradigm-changing and neotraditional works of the 21st century. Characteristics of speculative fiction have been recognized in older works whose authors' intentions are now known, or in the social contexts of the stories they tell. An example is the ancient Greek dramatist, Euripides (c. 480 – c. 406 BCE), whose play Medea seems to have offended Athenian audiences; in this play, he speculated that the titular sorceress Medea killed her own children, as opposed to their being killed by other Corinthians after her departure. In historiography, what is now called speculative fiction has previously been termed historical invention, historical fiction, and similar names. These terms have been extensively applied in literary criticism to the works of William Shakespeare. For example, in A Midsummer Night's Dream, he places several characters from different locations and times into the Fairyland of the fictional Merovingian Germanic sovereign Oberon; these characters include the Athenian Duke Theseus, the Amazonian Queen Hippolyta, the English fairy Puck, and the Roman god Cupid. In mythography, the concept of speculative fiction has been termed mythopoesis or mythopoeia. This process involves the creative design and development of lore and mythology for works of fiction. The term's definition comes from use by J. R. R. Tolkien; his series of novels, The Lord of the Rings, shows an application of the process. Themes common in mythopoeia, such as the supernatural, alternate history, and sexuality, continue to be explored in works produced in modern speculative fiction. Speculative fiction in the general sense of hypothetical history, explanation, or ahistorical storytelling has been attributed to authors in ostensibly non-fiction modes since Herodotus of Halicarnassus (fl. 5th century BCE) with his Histories; it was already both created and edited out by early encyclopedic writers such Sima Qian (c. 145 or 135 BCE–86 BCE), author of Shiji. These examples highlight a caveat—many works that are now viewed as speculative fiction long predated the labelling of the genre. In the broadest sense, the genre's concept does two things: it captures both conscious and unconscious aspects of human psychology in making sense of the world, and it responds to the world by creating imaginative, inventive, and artistic expressions. Such expressions can contribute to practical societal progress through interpersonal influences; social and cultural movements; scientific research and advances; and the philosophy of science. In English-language usage in arts and literature since the mid 20th century, the term speculative fiction has often been attributed to Robert A. Heinlein, who first used it in an editorial in The Saturday Evening Post (on 8 February 1947). In the article, Heinlein used Speculative Fiction as a synonym for science fiction; in a later article, he stated explicitly that his use of the term excluded fantasy. Although Heinlein may have invented the term independently, earlier citations exist. An article in Lippincott's Monthly Magazine in 1889 used the term in reference to Edward Bellamy's novel Looking Backward: 2000–1887 and other works; and an article in the May 1900 issue of The Bookman mentioned that John Uri Lloyd's novel Etidorhpa, or, The End of the Earth had "created a great deal of discussion among people interested in speculative fiction". A variant of this term is speculative literature. The use of the term speculative fiction to express dissatisfaction with traditional or establishment science fiction was popularized in the 1960s and early 1970s by Judith Merril, as well as other writers and editors connected with the New Wave movement. However, this use of the term became less popular toward the mid-1970s. During the 2000s, the term speculative fiction came into wider use as a convenient way to describe a set of genres. However, some writers (such as Margaret Atwood) still distinguish "speculative fiction" as a specifically "no Martians" type of science fiction, "about things that really could happen." The term speculative fiction is also used to describe genres combined into a single narrative or fictional world, such as "science fiction, horror, fantasy...[and]...mystery". In documenting this broad genre, the Internet Speculative Fiction Database includes a list of different subtypes. According to publisher statistics, men outnumber women about two to one among English-language speculative fiction writers who seek professional publication. However, the percentages vary considerably by genre, with women outnumbering men in the areas of urban fantasy, paranormal romance and young adult fiction. Academic journals that publish essays on speculative fiction include Extrapolation and Foundation. == Genres == Speculative fiction may include elements from one or more of the following genres: == See also == Biblical speculative fiction Comic genres Genre fiction List of genres Megatext Speculative art Speculative fiction by writers of color Speculative poetry Weird fiction == References == == External links == Internet Speculative Fiction Database The SF Page at Project Gutenberg of Australia
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https://en.wikipedia.org/wiki/Speculative_fiction
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Computational science, also known as scientific computing, technical computing or scientific computation (SC), is a division of science, and more specifically the Computer Sciences, which uses advanced computing capabilities to understand and solve complex physical problems. While this typically extends into computational specializations, this field of study includes: Algorithms (numerical and non-numerical): mathematical models, computational models, and computer simulations developed to solve sciences (e.g, physical, biological, and social), engineering, and humanities problems Computer hardware that develops and optimizes the advanced system hardware, firmware, networking, and data management components needed to solve computationally demanding problems The computing infrastructure that supports both the science and engineering problem solving and the developmental computer and information science In practical use, it is typically the application of computer simulation and other forms of computation from numerical analysis and theoretical computer science to solve problems in various scientific disciplines. The field is different from theory and laboratory experiments, which are the traditional forms of science and engineering. The scientific computing approach is to gain understanding through the analysis of mathematical models implemented on computers. Scientists and engineers develop computer programs and application software that model systems being studied and run these programs with various sets of input parameters. The essence of computational science is the application of numerical algorithms and computational mathematics. In some cases, these models require massive amounts of calculations (usually floating-point) and are often executed on supercomputers or distributed computing platforms. == The computational scientist == The term computational scientist is used to describe someone skilled in scientific computing. Such a person is usually a scientist, an engineer, or an applied mathematician who applies high-performance computing in different ways to advance the state-of-the-art in their respective applied disciplines in physics, chemistry, or engineering. Computational science is now commonly considered a third mode of science , complementing and adding to experimentation/observation and theory (see image). Here, one defines a system as a potential source of data, an experiment as a process of extracting data from a system by exerting it through its inputs and a model (M) for a system (S) and an experiment (E) as anything to which E can be applied in order to answer questions about S. A computational scientist should be capable of: recognizing complex problems adequately conceptualizing the system containing these problems designing a framework of algorithms suitable for studying this system: the simulation choosing a suitable computing infrastructure (parallel computing/grid computing/supercomputers) hereby, maximizing the computational power of the simulation assessing to what level the output of the simulation resembles the systems: the model is validated adjusting the conceptualization of the system accordingly repeat the cycle until a suitable level of validation is obtained: the computational scientist trusts that the simulation generates adequately realistic results for the system under the studied conditions Substantial effort in computational sciences has been devoted to developing algorithms, efficient implementation in programming languages, and validating computational results. A collection of problems and solutions in computational science can be found in Steeb, Hardy, Hardy, and Stoop (2004). Philosophers of science addressed the question to what degree computational science qualifies as science, among them Humphreys and Gelfert. They address the general question of epistemology: how does gain insight from such computational science approaches? Tolk uses these insights to show the epistemological constraints of computer-based simulation research. As computational science uses mathematical models representing the underlying theory in executable form, in essence, they apply modeling (theory building) and simulation (implementation and execution). While simulation and computational science are our most sophisticated way to express our knowledge and understanding, they also come with all constraints and limits already known for computational solutions. == Applications of computational science == Problem domains for computational science/scientific computing include: === Predictive computational science === Predictive computational science is a scientific discipline concerned with the formulation, calibration, numerical solution, and validation of mathematical models designed to predict specific aspects of physical events, given initial and boundary conditions, and a set of characterizing parameters and associated uncertainties. In typical cases, the predictive statement is formulated in terms of probabilities. For example, given a mechanical component and a periodic loading condition, "the probability is (say) 90% that the number of cycles at failure (Nf) will be in the interval N1<Nf<N2". === Urban complex systems === Cities are massively complex systems created by humans, made up of humans, and governed by humans. Trying to predict, understand and somehow shape the development of cities in the future requires complex thinking and computational models and simulations to help mitigate challenges and possible disasters. The focus of research in urban complex systems is, through modeling and simulation, to build a greater understanding of city dynamics and help prepare for the coming urbanization. === Computational finance === In financial markets, huge volumes of interdependent assets are traded by a large number of interacting market participants in different locations and time zones. Their behavior is of unprecedented complexity and the characterization and measurement of the risk inherent to this highly diverse set of instruments is typically based on complicated mathematical and computational models. Solving these models exactly in closed form, even at a single instrument level, is typically not possible, and therefore we have to look for efficient numerical algorithms. This has become even more urgent and complex recently, as the credit crisis has clearly demonstrated the role of cascading effects going from single instruments through portfolios of single institutions to even the interconnected trading network. Understanding this requires a multi-scale and holistic approach where interdependent risk factors such as market, credit, and liquidity risk are modeled simultaneously and at different interconnected scales. === Computational biology === Exciting new developments in biotechnology are now revolutionizing biology and biomedical research. Examples of these techniques are high-throughput sequencing, high-throughput quantitative PCR, intra-cellular imaging, in-situ hybridization of gene expression, three-dimensional imaging techniques like Light Sheet Fluorescence Microscopy, and Optical Projection (micro)-Computer Tomography. Given the massive amounts of complicated data that is generated by these techniques, their meaningful interpretation, and even their storage, form major challenges calling for new approaches. Going beyond current bioinformatics approaches, computational biology needs to develop new methods to discover meaningful patterns in these large data sets. Model-based reconstruction of gene networks can be used to organize the gene expression data in a systematic way and to guide future data collection. A major challenge here is to understand how gene regulation is controlling fundamental biological processes like biomineralization and embryogenesis. The sub-processes like gene regulation, organic molecules interacting with the mineral deposition process, cellular processes, physiology, and other processes at the tissue and environmental levels are linked. Rather than being directed by a central control mechanism, biomineralization and embryogenesis can be viewed as an emergent behavior resulting from a complex system in which several sub-processes on very different temporal and spatial scales (ranging from nanometer and nanoseconds to meters and years) are connected into a multi-scale system. One of the few available options to understand such systems is by developing a multi-scale model of the system. === Complex systems theory === Using information theory, non-equilibrium dynamics, and explicit simulations, computational systems theory tries to uncover the true nature of complex adaptive systems. === Computational science and engineering === Computational science and engineering (CSE) is a relatively new discipline that deals with the development and application of computational models and simulations, often coupled with high-performance computing, to solve complex physical problems arising in engineering analysis and design (computational engineering) as well as natural phenomena (computational science). CSE has become accepted amongst scientists, engineers and academics as the "third mode of discovery" (next to theory and experimentation). In many fields, computer simulation is integral and therefore essential to business and research. Computer simulation provides the capability to enter fields that are either inaccessible to traditional experimentation or where carrying out traditional empirical inquiries is prohibitively expensive. CSE should neither be confused with pure computer science, nor with computer engineering, although a wide domain in the former is used in CSE (e.g., certain algorithms, data structures, parallel programming, high-performance computing), and some problems in the latter can be modeled and solved with CSE methods (as an application area). == Methods and algorithms == Algorithms and mathematical methods used in computational science are varied. Commonly applied methods include: Historically and today, Fortran remains popular for most applications of scientific computing. Other programming languages and computer algebra systems commonly used for the more mathematical aspects of scientific computing applications include GNU Octave, Haskell, Julia, Maple, Mathematica, MATLAB, Python (with third-party SciPy library), Perl (with third-party PDL library), R, Scilab, and TK Solver. The more computationally intensive aspects of scientific computing will often use some variation of C or Fortran and optimized algebra libraries such as BLAS or LAPACK. In addition, parallel computing is heavily used in scientific computing to find solutions of large problems in a reasonable amount of time. In this framework, the problem is either divided over many cores on a single CPU node (such as with OpenMP), divided over many CPU nodes networked together (such as with MPI), or is run on one or more GPUs (typically using either CUDA or OpenCL). Computational science application programs often model real-world changing conditions, such as weather, airflow around a plane, automobile body distortions in a crash, the motion of stars in a galaxy, an explosive device, etc. Such programs might create a 'logical mesh' in computer memory where each item corresponds to an area in space and contains information about that space relevant to the model. For example, in weather models, each item might be a square kilometer; with land elevation, current wind direction, humidity, temperature, pressure, etc. The program would calculate the likely next state based on the current state, in simulated time steps, solving differential equations that describe how the system operates, and then repeat the process to calculate the next state. == Conferences and journals == In 2001, the International Conference on Computational Science (ICCS) was first organized. Since then, it has been organized yearly. ICCS is an A-rank conference in the CORE ranking. The Journal of Computational Science published its first issue in May 2010. The Journal of Open Research Software was launched in 2012. The ReScience C initiative, which is dedicated to replicating computational results, was started on GitHub in 2015. == Education == At some institutions, a specialization in scientific computation can be earned as a "minor" within another program (which may be at varying levels). However, there are increasingly many bachelor's, master's, and doctoral programs in computational science. The joint degree program master program computational science at the University of Amsterdam and the Vrije Universiteit in computational science was first offered in 2004. In this program, students: learn to build computational models from real-life observations; develop skills in turning these models into computational structures and in performing large-scale simulations; learn theories that will give a firm basis for the analysis of complex systems; learn to analyze the results of simulations in a virtual laboratory using advanced numerical algorithms. ETH Zurich offers a bachelor's and master's degree in Computational Science and Engineering. The degree equips students with the ability to understand scientific problem and apply numerical methods to solve such problems. The directions of specializations include Physics, Chemistry, Biology and other Scientific and Engineering disciplines. George Mason University has offered a multidisciplinary doctorate Ph.D. program in Computational Sciences and Informatics starting from 1992. The School of Computational and Integrative Sciences, Jawaharlal Nehru University (erstwhile School of Information Technology) also offers a vibrant master's science program for computational science with two specialties: Computational Biology and Complex Systems. === Subfields === == See also == Computational science and engineering Modeling and simulation Comparison of computer algebra systems Differentiable programming List of molecular modeling software List of numerical analysis software List of statistical packages Timeline of scientific computing Simulated reality Extensions for Scientific Computation (XSC) == References == == Additional sources == E. Gallopoulos and A. Sameh, "CSE: Content and Product". IEEE Computational Science and Engineering Magazine, 4(2):39–43 (1997) G. Hager and G. Wellein, Introduction to High Performance Computing for Scientists and Engineers, Chapman and Hall (2010) A.K. Hartmann, Practical Guide to Computer Simulations, World Scientific (2009) Journal Computational Methods in Science and Technology (open access), Polish Academy of Sciences Journal Computational Science and Discovery, Institute of Physics R.H. Landau, C.C. Bordeianu, and M. Jose Paez, A Survey of Computational Physics: Introductory Computational Science, Princeton University Press (2008) == External links == Journal of Computational Science The Journal of Open Research Software The National Center for Computational Science at Oak Ridge National Laboratory
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https://en.wikipedia.org/wiki/Computational_science
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Botany, also called plant science, is the branch of natural science and biology studying plants, especially their anatomy, taxonomy, and ecology. A botanist or plant scientist is a scientist who specialises in this field. "Plant" and "botany" may be defined more narrowly to include only land plants and their study, which is also known as phytology. Phytologists or botanists (in the strict sense) study approximately 410,000 species of land plants, including some 391,000 species of vascular plants (of which approximately 369,000 are flowering plants) and approximately 20,000 bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – plants that were edible, poisonous, and possibly medicinal, making it one of the first endeavours of human investigation. Medieval physic gardens, often attached to monasteries, contained plants possibly having medicinal benefit. They were forerunners of the first botanical gardens attached to universities, founded from the 1540s onwards. One of the earliest was the Padua botanical garden. These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy and led in 1753 to the binomial system of nomenclature of Carl Linnaeus that remains in use to this day for the naming of all biological species. In the 19th and 20th centuries, new techniques were developed for the study of plants, including methods of optical microscopy and live cell imaging, electron microscopy, analysis of chromosome number, plant chemistry and the structure and function of enzymes and other proteins. In the last two decades of the 20th century, botanists exploited the techniques of molecular genetic analysis, including genomics and proteomics and DNA sequences to classify plants more accurately. Modern botany is a broad subject with contributions and insights from most other areas of science and technology. Research topics include the study of plant structure, growth and differentiation, reproduction, biochemistry and primary metabolism, chemical products, development, diseases, evolutionary relationships, systematics, and plant taxonomy. Dominant themes in 21st-century plant science are molecular genetics and epigenetics, which study the mechanisms and control of gene expression during differentiation of plant cells and tissues. Botanical research has diverse applications in providing staple foods, materials such as timber, oil, rubber, fibre and drugs, in modern horticulture, agriculture and forestry, plant propagation, breeding and genetic modification, in the synthesis of chemicals and raw materials for construction and energy production, in environmental management, and the maintenance of biodiversity. == Etymology == The term "botany" comes from the Ancient Greek word botanē (βοτάνη) meaning "pasture", "herbs" "grass", or "fodder"; Botanē is in turn derived from boskein (Greek: βόσκειν), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. == History == === Early botany === Botany originated as herbalism, the study and use of plants for their possible medicinal properties. The early recorded history of botany includes many ancient writings and plant classifications. Examples of early botanical works have been found in ancient texts from India dating back to before 1100 BCE, Ancient Egypt, in archaic Avestan writings, and in works from China purportedly from before 221 BCE. Modern botany traces its roots back to Ancient Greece specifically to Theophrastus (c. 371–287 BCE), a student of Aristotle who invented and described many of its principles and is widely regarded in the scientific community as the "Father of Botany". His major works, Enquiry into Plants and On the Causes of Plants, constitute the most important contributions to botanical science until the Middle Ages, almost seventeen centuries later. Another work from Ancient Greece that made an early impact on botany is De materia medica, a five-volume encyclopedia about preliminary herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides. De materia medica was widely read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya's Nabatean Agriculture, Abū Ḥanīfa Dīnawarī's (828–896) the Book of Plants, and Ibn Bassal's The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, and Ibn al-Baitar (d. 1248) wrote on botany in a systematic and scientific manner. In the mid-16th century, botanical gardens were founded in a number of Italian universities. The Padua botanical garden in 1545 is usually considered to be the first which is still in its original location. These gardens continued the practical value of earlier "physic gardens", often associated with monasteries, in which plants were cultivated for suspected medicinal uses. They supported the growth of botany as an academic subject. Lectures were given about the plants grown in the gardens. Botanical gardens came much later to northern Europe; the first in England was the University of Oxford Botanic Garden in 1621. German physician Leonhart Fuchs (1501–1566) was one of "the three German fathers of botany", along with theologian Otto Brunfels (1489–1534) and physician Hieronymus Bock (1498–1554) (also called Hieronymus Tragus). Fuchs and Brunfels broke away from the tradition of copying earlier works to make original observations of their own. Bock created his own system of plant classification. Physician Valerius Cordus (1515–1544) authored a botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Naturalist Conrad von Gesner (1516–1565) and herbalist John Gerard (1545 – c. 1611) published herbals covering the supposed medicinal uses of plants. Naturalist Ulisse Aldrovandi (1522–1605) was considered the father of natural history, which included the study of plants. In 1665, using an early microscope, Polymath Robert Hooke discovered cells (a term he coined) in cork, and a short time later in living plant tissue. === Early modern botany === During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters. The choice and sequence of the characters may be artificial in keys designed purely for identification (diagnostic keys) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753, Carl Linnaeus published his Species Plantarum, a hierarchical classification of plant species that remains the reference point for modern botanical nomenclature. This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to the number of their male sexual organs. The 24th group, Cryptogamia, included all plants with concealed reproductive parts, mosses, liverworts, ferns, algae and fungi. Increasing knowledge of plant anatomy, morphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems of classification that grouped plants using a wider range of shared characters and were widely followed. The Candollean system reflected his ideas of the progression of morphological complexity and the later Bentham & Hooker system, which was influential until the mid-19th century, was influenced by Candolle's approach. Darwin's publication of the Origin of Species in 1859 and his concept of common descent required modifications to the Candollean system to reflect evolutionary relationships as distinct from mere morphological similarity. In the 19th century botany was a socially acceptable hobby for upper-class women. These women would collect and paint flowers and plants from around the world with scientific accuracy. The paintings were used to record many species that could not be transported or maintained in other environments. Marianne North illustrated over 900 species in extreme detail with watercolor and oil paintings. Her work and many other women's botany work was the beginning of popularizing botany to a wider audience. Botany was greatly stimulated by the appearance of the first "modern" textbook, Matthias Schleiden's Grundzüge der Wissenschaftlichen Botanik, published in English in 1849 as Principles of Scientific Botany. Schleiden was a microscopist and an early plant anatomist who co-founded the cell theory with Theodor Schwann and Rudolf Virchow and was among the first to grasp the significance of the cell nucleus that had been described by Robert Brown in 1831. In 1855, Adolf Fick formulated Fick's laws that enabled the calculation of the rates of molecular diffusion in biological systems. === Late modern botany === Building upon the gene-chromosome theory of heredity that originated with Gregor Mendel (1822–1884), August Weismann (1834–1914) proved that inheritance only takes place through gametes. No other cells can pass on inherited characters. The work of Katherine Esau (1898–1997) on plant anatomy is still a major foundation of modern botany. Her books Plant Anatomy and Anatomy of Seed Plants have been key plant structural biology texts for more than half a century. The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warming, who produced the hypothesis that plants form communities, and his mentor and successor Christen C. Raunkiær whose system for describing plant life forms is still in use today. The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler Cowles, Arthur Tansley and Frederic Clements. Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Building on the extensive earlier work of Alphonse de Candolle, Nikolai Vavilov (1887–1943) produced accounts of the biogeography, centres of origin, and evolutionary history of economic plants. Particularly since the mid-1960s there have been advances in understanding of the physics of plant physiological processes such as transpiration (the transport of water within plant tissues), the temperature dependence of rates of water evaporation from the leaf surface and the molecular diffusion of water vapour and carbon dioxide through stomatal apertures. These developments, coupled with new methods for measuring the size of stomatal apertures, and the rate of photosynthesis have enabled precise description of the rates of gas exchange between plants and the atmosphere. Innovations in statistical analysis by Ronald Fisher, Frank Yates and others at Rothamsted Experimental Station facilitated rational experimental design and data analysis in botanical research. The discovery and identification of the auxin plant hormones by Kenneth V. Thimann in 1948 enabled regulation of plant growth by externally applied chemicals. Frederick Campion Steward pioneered techniques of micropropagation and plant tissue culture controlled by plant hormones. The synthetic auxin 2,4-dichlorophenoxyacetic acid or 2,4-D was one of the first commercial synthetic herbicides. 20th century developments in plant biochemistry have been driven by modern techniques of organic chemical analysis, such as spectroscopy, chromatography and electrophoresis. With the rise of the related molecular-scale biological approaches of molecular biology, genomics, proteomics and metabolomics, the relationship between the plant genome and most aspects of the biochemistry, physiology, morphology and behaviour of plants can be subjected to detailed experimental analysis. The concept originally stated by Gottlieb Haberlandt in 1902 that all plant cells are totipotent and can be grown in vitro ultimately enabled the use of genetic engineering experimentally to knock out a gene or genes responsible for a specific trait, or to add genes such as GFP that report when a gene of interest is being expressed. These technologies enable the biotechnological use of whole plants or plant cell cultures grown in bioreactors to synthesise pesticides, antibiotics or other pharmaceuticals, as well as the practical application of genetically modified crops designed for traits such as improved yield. Modern morphology recognises a continuum between the major morphological categories of root, stem (caulome), leaf (phyllome) and trichome. Furthermore, it emphasises structural dynamics. Modern systematics aims to reflect and discover phylogenetic relationships between plants. Modern molecular phylogenetics largely ignores morphological characters, relying on DNA sequences as data. Molecular analysis of DNA sequences from most families of flowering plants enabled the Angiosperm Phylogeny Group to publish in 1998 a phylogeny of flowering plants, answering many of the questions about relationships among angiosperm families and species. The theoretical possibility of a practical method for identification of plant species and commercial varieties by DNA barcoding is the subject of active current research. == Branches of botany == Botany is divided along several axes. Some subfields of botany relate to particular groups of organisms. Divisions related to the broader historical sense of botany include bacteriology, mycology (or fungology), and phycology – respectively, the study of bacteria, fungi, and algae – with lichenology as a subfield of mycology. The narrower sense of botany as the study of embryophytes (land plants) is called phytology. Bryology is the study of mosses (and in the broader sense also liverworts and hornworts). Pteridology (or filicology) is the study of ferns and allied plants. A number of other taxa of ranks varying from family to subgenus have terms for their study, including agrostology (or graminology) for the study of grasses, synantherology for the study of composites, and batology for the study of brambles. Study can also be divided by guild rather than clade or grade. For example, dendrology is the study of woody plants. Many divisions of biology have botanical subfields. These are commonly denoted by prefixing the word plant (e.g. plant taxonomy, plant ecology, plant anatomy, plant morphology, plant systematics), or prefixing or substituting the prefix phyto- (e.g. phytochemistry, phytogeography). The study of fossil plants is called palaeobotany. Other fields are denoted by adding or substituting the word botany (e.g. systematic botany). Phytosociology is a subfield of plant ecology that classifies and studies communities of plants. The intersection of fields from the above pair of categories gives rise to fields such as bryogeography, the study of the distribution of mosses. Different parts of plants also give rise to their own subfields, including xylology, carpology (or fructology), and palynology, these being the study of wood, fruit and pollen/spores respectively. Botany also overlaps on the one hand with agriculture, horticulture and silviculture, and on the other hand with medicine and pharmacology, giving rise to fields such as agronomy, horticultural botany, phytopathology, and phytopharmacology. == Scope and importance == The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are the major groups of organisms that carry out photosynthesis, a process that uses the energy of sunlight to convert water and carbon dioxide into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells. As a by-product of photosynthesis, plants release oxygen into the atmosphere, a gas that is required by nearly all living things to carry out cellular respiration. In addition, they are influential in the global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion. Plants are crucial to the future of human society as they provide food, oxygen, biochemicals, and products for people, as well as creating and preserving soil. Historically, all living things were classified as either animals or plants and botany covered the study of all organisms not considered animals. Botanists examine both the internal functions and processes within plant organelles, cells, tissues, whole plants, plant populations and plant communities. At each of these levels, a botanist may be concerned with the classification (taxonomy), phylogeny and evolution, structure (anatomy and morphology), or function (physiology) of plant life. The strictest definition of "plant" includes only the "land plants" or embryophytes, which include seed plants (gymnosperms, including the pines, and flowering plants) and the free-sporing cryptogams including ferns, clubmosses, liverworts, hornworts and mosses. Embryophytes are multicellular eukaryotes descended from an ancestor that obtained its energy from sunlight by photosynthesis. They have life cycles with alternating haploid and diploid phases. The sexual haploid phase of embryophytes, known as the gametophyte, nurtures the developing diploid embryo sporophyte within its tissues for at least part of its life, even in the seed plants, where the gametophyte itself is nurtured by its parent sporophyte. Other groups of organisms that were previously studied by botanists include bacteria (now studied in bacteriology), fungi (mycology) – including lichen-forming fungi (lichenology), non-chlorophyte algae (phycology), and viruses (virology). However, attention is still given to these groups by botanists, and fungi (including lichens) and photosynthetic protists are usually covered in introductory botany courses. Palaeobotanists study ancient plants in the fossil record to provide information about the evolutionary history of plants. Cyanobacteria, the first oxygen-releasing photosynthetic organisms on Earth, are thought to have given rise to the ancestor of plants by entering into an endosymbiotic relationship with an early eukaryote, ultimately becoming the chloroplasts in plant cells. The new photosynthetic plants (along with their algal relatives) accelerated the rise in atmospheric oxygen started by the cyanobacteria, changing the ancient oxygen-free, reducing, atmosphere to one in which free oxygen has been abundant for more than 2 billion years. Among the important botanical questions of the 21st century are the role of plants as primary producers in the global cycling of life's basic ingredients: energy, carbon, oxygen, nitrogen and water, and ways that our plant stewardship can help address the global environmental issues of resource management, conservation, human food security, biologically invasive organisms, carbon sequestration, climate change, and sustainability. === Human nutrition === Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them. Plants and other photosynthetic organisms are at the base of most food chains because they use the energy from the sun and nutrients from the soil and atmosphere, converting them into a form that can be used by animals. This is what ecologists call the first trophic level. The modern forms of the major staple foods, such as hemp, teff, maize, rice, wheat and other cereal grasses, pulses, bananas and plantains, as well as hemp, flax and cotton grown for their fibres, are the outcome of prehistoric selection over thousands of years from among wild ancestral plants with the most desirable characteristics. Botanists study how plants produce food and how to increase yields, for example through plant breeding, making their work important to humanity's ability to feed the world and provide food security for future generations. Botanists also study weeds, which are a considerable problem in agriculture, and the biology and control of plant pathogens in agriculture and natural ecosystems. Ethnobotany is the study of the relationships between plants and people. When applied to the investigation of historical plant–people relationships ethnobotany may be referred to as archaeobotany or palaeoethnobotany. Some of the earliest plant-people relationships arose between the indigenous people of Canada in identifying edible plants from inedible plants. This relationship the indigenous people had with plants was recorded by ethnobotanists. == Plant biochemistry == Plant biochemistry is the study of the chemical processes used by plants. Some of these processes are used in their primary metabolism like the photosynthetic Calvin cycle and crassulacean acid metabolism. Others make specialised materials like the cellulose and lignin used to build their bodies, and secondary products like resins and aroma compounds. Plants and various other groups of photosynthetic eukaryotes collectively known as "algae" have unique organelles known as chloroplasts. Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain the blue-green pigment chlorophyll a. Chlorophyll a (as well as its plant and green algal-specific cousin chlorophyll b) absorbs light in the blue-violet and orange/red parts of the spectrum while reflecting and transmitting the green light that we see as the characteristic colour of these organisms. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesis, a process that generates molecular oxygen (O2) as a by-product. The light energy captured by chlorophyll a is initially in the form of electrons (and later a proton gradient) that is used to make molecules of ATP and NADPH which temporarily store and transport energy. Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of the 3-carbon sugar glyceraldehyde 3-phosphate (G3P). Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesised. Some of the glucose is converted to starch which is stored in the chloroplast. Starch is the characteristic energy store of most land plants and algae, while inulin, a polymer of fructose is used for the same purpose in the sunflower family Asteraceae. Some of the glucose is converted to sucrose (common table sugar) for export to the rest of the plant. Unlike in animals (which lack chloroplasts), plants and their eukaryote relatives have delegated many biochemical roles to their chloroplasts, including synthesising all their fatty acids, and most amino acids. The fatty acids that chloroplasts make are used for many things, such as providing material to build cell membranes out of and making the polymer cutin which is found in the plant cuticle that protects land plants from drying out. Plants synthesise a number of unique polymers like the polysaccharide molecules cellulose, pectin and xyloglucan from which the land plant cell wall is constructed. Vascular land plants make lignin, a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when a plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibres that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in the fossil record. It is widely regarded as a marker for the start of land plant evolution during the Ordovician period. The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods. Many monocots like maize and the pineapple and some dicots like the Asteraceae have since independently evolved pathways like Crassulacean acid metabolism and the C4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration in the more common C3 carbon fixation pathway. These biochemical strategies are unique to land plants. === Medicine and materials === Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism. Some of these compounds are toxins such as the alkaloid coniine from hemlock. Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices (e.g., capsaicin), and in medicine as pharmaceuticals as in opium from opium poppies. Many medicinal and recreational drugs, such as tetrahydrocannabinol (active ingredient in cannabis), caffeine, morphine and nicotine come directly from plants. Others are simple derivatives of botanical natural products. For example, the pain killer aspirin is the acetyl ester of salicylic acid, originally isolated from the bark of willow trees, and a wide range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy. Popular stimulants come from plants, such as caffeine from coffee, tea and chocolate, and nicotine from tobacco. Most alcoholic beverages come from fermentation of carbohydrate-rich plant products such as barley (beer), rice (sake) and grapes (wine). Native Americans have used various plants as ways of treating illness or disease for thousands of years. This knowledge Native Americans have on plants has been recorded by enthnobotanists and then in turn has been used by pharmaceutical companies as a way of drug discovery. Plants can synthesise coloured dyes and pigments such as the anthocyanins responsible for the red colour of red wine, yellow weld and blue woad used together to produce Lincoln green, indoxyl, source of the blue dye indigo traditionally used to dye denim and the artist's pigments gamboge and rose madder. Sugar, starch, cotton, linen, hemp, some types of rope, wood and particle boards, papyrus and paper, vegetable oils, wax, and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal, a pure form of carbon made by pyrolysis of wood, has a long history as a metal-smelting fuel, as a filter material and adsorbent and as an artist's material and is one of the three ingredients of gunpowder. Cellulose, the world's most abundant organic polymer, can be converted into energy, fuels, materials and chemical feedstock. Products made from cellulose include rayon and cellophane, wallpaper paste, biobutanol and gun cotton. Sugarcane, rapeseed and soy are some of the plants with a highly fermentable sugar or oil content that are used as sources of biofuels, important alternatives to fossil fuels, such as biodiesel. Sweetgrass was used by Native Americans to ward off bugs like mosquitoes. These bug repelling properties of sweetgrass were later found by the American Chemical Society in the molecules phytol and coumarin. == Plant ecology == Plant ecology is the science of the functional relationships between plants and their habitats – the environments where they complete their life cycles. Plant ecologists study the composition of local and regional floras, their biodiversity, genetic diversity and fitness, the adaptation of plants to their environment, and their competitive or mutualistic interactions with other species. Some ecologists even rely on empirical data from indigenous people that is gathered by ethnobotanists. This information can relay a great deal of information on how the land once was thousands of years ago and how it has changed over that time. The goals of plant ecology are to understand the causes of their distribution patterns, productivity, environmental impact, evolution, and responses to environmental change. Plants depend on certain edaphic (soil) and climatic factors in their environment but can modify these factors too. For example, they can change their environment's albedo, increase runoff interception, stabilise mineral soils and develop their organic content, and affect local temperature. Plants compete with other organisms in their ecosystem for resources. They interact with their neighbours at a variety of spatial scales in groups, populations and communities that collectively constitute vegetation. Regions with characteristic vegetation types and dominant plants as well as similar abiotic and biotic factors, climate, and geography make up biomes like tundra or tropical rainforest. Herbivores eat plants, but plants can defend themselves and some species are parasitic or even carnivorous. Other organisms form mutually beneficial relationships with plants. For example, mycorrhizal fungi and rhizobia provide plants with nutrients in exchange for food, ants are recruited by ant plants to provide protection, honey bees, bats and other animals pollinate flowers and humans and other animals act as dispersal vectors to spread spores and seeds. === Plants, climate and environmental change === Plant responses to climate and other environmental changes can inform our understanding of how these changes affect ecosystem function and productivity. For example, plant phenology can be a useful proxy for temperature in historical climatology, and the biological impact of climate change and global warming. Palynology, the analysis of fossil pollen deposits in sediments from thousands or millions of years ago allows the reconstruction of past climates. Estimates of atmospheric CO2 concentrations since the Palaeozoic have been obtained from stomatal densities and the leaf shapes and sizes of ancient land plants. Ozone depletion can expose plants to higher levels of ultraviolet radiation-B (UV-B), resulting in lower growth rates. Moreover, information from studies of community ecology, plant systematics, and taxonomy is essential to understanding vegetation change, habitat destruction and species extinction. == Genetics == Inheritance in plants follows the same fundamental principles of genetics as in other multicellular organisms. Gregor Mendel discovered the genetic laws of inheritance by studying inherited traits such as shape in Pisum sativum (peas). What Mendel learned from studying plants has had far-reaching benefits outside of botany. Similarly, "jumping genes" were discovered by Barbara McClintock while she was studying maize. Nevertheless, there are some distinctive genetic differences between plants and other organisms. Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example is peppermint, Mentha × piperita, a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata. The many cultivated varieties of wheat are the result of multiple inter- and intra-specific crosses between wild species and their hybrids. Angiosperms with monoecious flowers often have self-incompatibility mechanisms that operate between the pollen and stigma so that the pollen either fails to reach the stigma or fails to germinate and produce male gametes. This is one of several methods used by plants to promote outcrossing. In many land plants the male and female gametes are produced by separate individuals. These species are said to be dioecious when referring to vascular plant sporophytes and dioicous when referring to bryophyte gametophytes. Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom at the start of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." An important adaptive benefit of outcrossing is that it allows the masking of deleterious mutations in the genome of progeny. This beneficial effect is also known as hybrid vigor or heterosis. Once outcrossing is established, subsequent switching to inbreeding becomes disadvantageous since it allows expression of the previously masked deleterious recessive mutations, commonly referred to as inbreeding depression. Unlike in higher animals, where parthenogenesis is rare, asexual reproduction may occur in plants by several different mechanisms. The formation of stem tubers in potato is one example. Particularly in arctic or alpine habitats, where opportunities for fertilisation of flowers by animals are rare, plantlets or bulbs, may develop instead of flowers, replacing sexual reproduction with asexual reproduction and giving rise to clonal populations genetically identical to the parent. This is one of several types of apomixis that occur in plants. Apomixis can also happen in a seed, producing a seed that contains an embryo genetically identical to the parent. Most sexually reproducing organisms are diploid, with paired chromosomes, but doubling of their chromosome number may occur due to errors in cytokinesis. This can occur early in development to produce an autopolyploid or partly autopolyploid organism, or during normal processes of cellular differentiation to produce some cell types that are polyploid (endopolyploidy), or during gamete formation. An allopolyploid plant may result from a hybridisation event between two different species. Both autopolyploid and allopolyploid plants can often reproduce normally, but may be unable to cross-breed successfully with the parent population because there is a mismatch in chromosome numbers. These plants that are reproductively isolated from the parent species but live within the same geographical area, may be sufficiently successful to form a new species. Some otherwise sterile plant polyploids can still reproduce vegetatively or by seed apomixis, forming clonal populations of identical individuals. Durum wheat is a fertile tetraploid allopolyploid, while bread wheat is a fertile hexaploid. The commercial banana is an example of a sterile, seedless triploid hybrid. Common dandelion is a triploid that produces viable seeds by apomictic seed. As in other eukaryotes, the inheritance of endosymbiotic organelles like mitochondria and chloroplasts in plants is non-Mendelian. Chloroplasts are inherited through the male parent in gymnosperms but often through the female parent in flowering plants. === Molecular genetics === A considerable amount of new knowledge about plant function comes from studies of the molecular genetics of model plants such as the Thale cress, Arabidopsis thaliana, a weedy species in the mustard family (Brassicaceae). The genome or hereditary information contained in the genes of this species is encoded by about 135 million base pairs of DNA, forming one of the smallest genomes among flowering plants. Arabidopsis was the first plant to have its genome sequenced, in 2000. The sequencing of some other relatively small genomes, of rice (Oryza sativa) and Brachypodium distachyon, has made them important model species for understanding the genetics, cellular and molecular biology of cereals, grasses and monocots generally. Model plants such as Arabidopsis thaliana are used for studying the molecular biology of plant cells and the chloroplast. Ideally, these organisms have small genomes that are well known or completely sequenced, small stature and short generation times. Corn has been used to study mechanisms of photosynthesis and phloem loading of sugar in C4 plants. The single celled green alga Chlamydomonas reinhardtii, while not an embryophyte itself, contains a green-pigmented chloroplast related to that of land plants, making it useful for study. A red alga Cyanidioschyzon merolae has also been used to study some basic chloroplast functions. Spinach, peas, soybeans and a moss Physcomitrella patens are commonly used to study plant cell biology. Agrobacterium tumefaciens, a soil rhizosphere bacterium, can attach to plant cells and infect them with a callus-inducing Ti plasmid by horizontal gene transfer, causing a callus infection called crown gall disease. Schell and Van Montagu (1977) hypothesised that the Ti plasmid could be a natural vector for introducing the Nif gene responsible for nitrogen fixation in the root nodules of legumes and other plant species. Today, genetic modification of the Ti plasmid is one of the main techniques for introduction of transgenes to plants and the creation of genetically modified crops. === Epigenetics === Epigenetics is the study of heritable changes in gene function that cannot be explained by changes in the underlying DNA sequence but cause the organism's genes to behave (or "express themselves") differently. One example of epigenetic change is the marking of the genes by DNA methylation which determines whether they will be expressed or not. Gene expression can also be controlled by repressor proteins that attach to silencer regions of the DNA and prevent that region of the DNA code from being expressed. Epigenetic marks may be added or removed from the DNA during programmed stages of development of the plant, and are responsible, for example, for the differences between anthers, petals and normal leaves, despite the fact that they all have the same underlying genetic code. Epigenetic changes may be temporary or may remain through successive cell divisions for the remainder of the cell's life. Some epigenetic changes have been shown to be heritable, while others are reset in the germ cells. Epigenetic changes in eukaryotic biology serve to regulate the process of cellular differentiation. During morphogenesis, totipotent stem cells become the various pluripotent cell lines of the embryo, which in turn become fully differentiated cells. A single fertilised egg cell, the zygote, gives rise to the many different plant cell types including parenchyma, xylem vessel elements, phloem sieve tubes, guard cells of the epidermis, etc. as it continues to divide. The process results from the epigenetic activation of some genes and inhibition of others. Unlike animals, many plant cells, particularly those of the parenchyma, do not terminally differentiate, remaining totipotent with the ability to give rise to a new individual plant. Exceptions include highly lignified cells, the sclerenchyma and xylem which are dead at maturity, and the phloem sieve tubes which lack nuclei. While plants use many of the same epigenetic mechanisms as animals, such as chromatin remodelling, an alternative hypothesis is that plants set their gene expression patterns using positional information from the environment and surrounding cells to determine their developmental fate. Epigenetic changes can lead to paramutations, which do not follow the Mendelian heritage rules. These epigenetic marks are carried from one generation to the next, with one allele inducing a change on the other. == Plant evolution == The chloroplasts of plants have a number of biochemical, structural and genetic similarities to cyanobacteria, (commonly but incorrectly known as "blue-green algae") and are thought to be derived from an ancient endosymbiotic relationship between an ancestral eukaryotic cell and a cyanobacterial resident. The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina. Nonvascular land plants are embryophytes that lack the vascular tissues xylem and phloem. They include mosses, liverworts and hornworts. Pteridophytic vascular plants with true xylem and phloem that reproduced by spores germinating into free-living gametophytes evolved during the Silurian period and diversified into several lineages during the late Silurian and early Devonian. Representatives of the lycopods have survived to the present day. By the end of the Devonian period, several groups, including the lycopods, sphenophylls and progymnosperms, had independently evolved "megaspory" – their spores were of two distinct sizes, larger megaspores and smaller microspores. Their reduced gametophytes developed from megaspores retained within the spore-producing organs (megasporangia) of the sporophyte, a condition known as endospory. Seeds consist of an endosporic megasporangium surrounded by one or two sheathing layers (integuments). The young sporophyte develops within the seed, which on germination splits to release it. The earliest known seed plants date from the latest Devonian Famennian stage. Following the evolution of the seed habit, seed plants diversified, giving rise to a number of now-extinct groups, including seed ferns, as well as the modern gymnosperms and angiosperms. Gymnosperms produce "naked seeds" not fully enclosed in an ovary; modern representatives include conifers, cycads, Ginkgo, and Gnetales. Angiosperms produce seeds enclosed in a structure such as a carpel or an ovary. Ongoing research on the molecular phylogenetics of living plants appears to show that the angiosperms are a sister clade to the gymnosperms. == Plant physiology == Plant physiology encompasses all the internal chemical and physical activities of plants associated with life. Chemicals obtained from the air, soil and water form the basis of all plant metabolism. The energy of sunlight, captured by oxygenic photosynthesis and released by cellular respiration, is the basis of almost all life. Photoautotrophs, including all green plants, algae and cyanobacteria gather energy directly from sunlight by photosynthesis. Heterotrophs including all animals, all fungi, all completely parasitic plants, and non-photosynthetic bacteria take in organic molecules produced by photoautotrophs and respire them or use them in the construction of cells and tissues. Respiration is the oxidation of carbon compounds by breaking them down into simpler structures to release the energy they contain, essentially the opposite of photosynthesis. Molecules are moved within plants by transport processes that operate at a variety of spatial scales. Subcellular transport of ions, electrons and molecules such as water and enzymes occurs across cell membranes. Minerals and water are transported from roots to other parts of the plant in the transpiration stream. Diffusion, osmosis, and active transport and mass flow are all different ways transport can occur. Examples of elements that plants need to transport are nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. In vascular plants, these elements are extracted from the soil as soluble ions by the roots and transported throughout the plant in the xylem. Most of the elements required for plant nutrition come from the chemical breakdown of soil minerals. Sucrose produced by photosynthesis is transported from the leaves to other parts of the plant in the phloem and plant hormones are transported by a variety of processes. === Plant hormones === Plants are not passive, but respond to external signals such as light, touch, and injury by moving or growing towards or away from the stimulus, as appropriate. Tangible evidence of touch sensitivity is the almost instantaneous collapse of leaflets of Mimosa pudica, the insect traps of Venus flytrap and bladderworts, and the pollinia of orchids. The hypothesis that plant growth and development is coordinated by plant hormones or plant growth regulators first emerged in the late 19th century. Darwin experimented on the movements of plant shoots and roots towards light and gravity, and concluded "It is hardly an exaggeration to say that the tip of the radicle . . acts like the brain of one of the lower animals . . directing the several movements". About the same time, the role of auxins (from the Greek auxein, to grow) in control of plant growth was first outlined by the Dutch scientist Frits Went. The first known auxin, indole-3-acetic acid (IAA), which promotes cell growth, was only isolated from plants about 50 years later. This compound mediates the tropic responses of shoots and roots towards light and gravity. The finding in 1939 that plant callus could be maintained in culture containing IAA, followed by the observation in 1947 that it could be induced to form roots and shoots by controlling the concentration of growth hormones were key steps in the development of plant biotechnology and genetic modification. Cytokinins are a class of plant hormones named for their control of cell division (especially cytokinesis). The natural cytokinin zeatin was discovered in corn, Zea mays, and is a derivative of the purine adenine. Zeatin is produced in roots and transported to shoots in the xylem where it promotes cell division, bud development, and the greening of chloroplasts. The gibberelins, such as gibberelic acid are diterpenes synthesised from acetyl CoA via the mevalonate pathway. They are involved in the promotion of germination and dormancy-breaking in seeds, in regulation of plant height by controlling stem elongation and the control of flowering. Abscisic acid (ABA) occurs in all land plants except liverworts, and is synthesised from carotenoids in the chloroplasts and other plastids. It inhibits cell division, promotes seed maturation, and dormancy, and promotes stomatal closure. It was so named because it was originally thought to control abscission. Ethylene is a gaseous hormone that is produced in all higher plant tissues from methionine. It is now known to be the hormone that stimulates or regulates fruit ripening and abscission, and it, or the synthetic growth regulator ethephon which is rapidly metabolised to produce ethylene, are used on industrial scale to promote ripening of cotton, pineapples and other climacteric crops. Another class of phytohormones is the jasmonates, first isolated from the oil of Jasminum grandiflorum which regulates wound responses in plants by unblocking the expression of genes required in the systemic acquired resistance response to pathogen attack. In addition to being the primary energy source for plants, light functions as a signalling device, providing information to the plant, such as how much sunlight the plant receives each day. This can result in adaptive changes in a process known as photomorphogenesis. Phytochromes are the photoreceptors in a plant that are sensitive to light. == Plant anatomy and morphology == Plant anatomy is the study of the structure of plant cells and tissues, whereas plant morphology is the study of their external form. All plants are multicellular eukaryotes, their DNA stored in nuclei. The characteristic features of plant cells that distinguish them from those of animals and fungi include a primary cell wall composed of the polysaccharides cellulose, hemicellulose and pectin, larger vacuoles than in animal cells and the presence of plastids with unique photosynthetic and biosynthetic functions as in the chloroplasts. Other plastids contain storage products such as starch (amyloplasts) or lipids (elaioplasts). Uniquely, streptophyte cells and those of the green algal order Trentepohliales divide by construction of a phragmoplast as a template for building a cell plate late in cell division. The bodies of vascular plants including clubmosses, ferns and seed plants (gymnosperms and angiosperms) generally have aerial and subterranean subsystems. The shoots consist of stems bearing green photosynthesising leaves and reproductive structures. The underground vascularised roots bear root hairs at their tips and generally lack chlorophyll. Non-vascular plants, the liverworts, hornworts and mosses do not produce ground-penetrating vascular roots and most of the plant participates in photosynthesis. The sporophyte generation is nonphotosynthetic in liverworts but may be able to contribute part of its energy needs by photosynthesis in mosses and hornworts. The root system and the shoot system are interdependent – the usually nonphotosynthetic root system depends on the shoot system for food, and the usually photosynthetic shoot system depends on water and minerals from the root system. Cells in each system are capable of creating cells of the other and producing adventitious shoots or roots. Stolons and tubers are examples of shoots that can grow roots. Roots that spread out close to the surface, such as those of willows, can produce shoots and ultimately new plants. In the event that one of the systems is lost, the other can often regrow it. In fact it is possible to grow an entire plant from a single leaf, as is the case with plants in Streptocarpus sect. Saintpaulia, or even a single cell – which can dedifferentiate into a callus (a mass of unspecialised cells) that can grow into a new plant. In vascular plants, the xylem and phloem are the conductive tissues that transport resources between shoots and roots. Roots are often adapted to store food such as sugars or starch, as in sugar beets and carrots. Stems mainly provide support to the leaves and reproductive structures, but can store water in succulent plants such as cacti, food as in potato tubers, or reproduce vegetatively as in the stolons of strawberry plants or in the process of layering. Leaves gather sunlight and carry out photosynthesis. Large, flat, flexible, green leaves are called foliage leaves. Gymnosperms, such as conifers, cycads, Ginkgo, and gnetophytes are seed-producing plants with open seeds. Angiosperms are seed-producing plants that produce flowers and have enclosed seeds. Woody plants, such as azaleas and oaks, undergo a secondary growth phase resulting in two additional types of tissues: wood (secondary xylem) and bark (secondary phloem and cork). All gymnosperms and many angiosperms are woody plants. Some plants reproduce sexually, some asexually, and some via both means. Although reference to major morphological categories such as root, stem, leaf, and trichome are useful, one has to keep in mind that these categories are linked through intermediate forms so that a continuum between the categories results. Furthermore, structures can be seen as processes, that is, process combinations. == Systematic botany == Systematic botany is part of systematic biology, which is concerned with the range and diversity of organisms and their relationships, particularly as determined by their evolutionary history. It involves, or is related to, biological classification, scientific taxonomy and phylogenetics. Biological classification is the method by which botanists group organisms into categories such as genera or species. Biological classification is a form of scientific taxonomy. Modern taxonomy is rooted in the work of Carl Linnaeus, who grouped species according to shared physical characteristics. These groupings have since been revised to align better with the Darwinian principle of common descent – grouping organisms by ancestry rather than superficial characteristics. While scientists do not always agree on how to classify organisms, molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions along evolutionary lines and is likely to continue to do so. The dominant classification system is called Linnaean taxonomy. It includes ranks and binomial nomenclature. The nomenclature of botanical organisms is codified in the International Code of Nomenclature for algae, fungi, and plants (ICN) and administered by the International Botanical Congress. Kingdom Plantae belongs to Domain Eukaryota and is broken down recursively until each species is separately classified. The order is: Kingdom; Phylum (or Division); Class; Order; Family; Genus (plural genera); Species. The scientific name of a plant represents its genus and its species within the genus, resulting in a single worldwide name for each organism. For example, the tiger lily is Lilium columbianum. Lilium is the genus, and columbianum the specific epithet. The combination is the name of the species. When writing the scientific name of an organism, it is proper to capitalise the first letter in the genus and put all of the specific epithet in lowercase. Additionally, the entire term is ordinarily italicised (or underlined when italics are not available). The evolutionary relationships and heredity of a group of organisms is called its phylogeny. Phylogenetic studies attempt to discover phylogenies. The basic approach is to use similarities based on shared inheritance to determine relationships. As an example, species of Pereskia are trees or bushes with prominent leaves. They do not obviously resemble a typical leafless cactus such as an Echinocactus. However, both Pereskia and Echinocactus have spines produced from areoles (highly specialised pad-like structures) suggesting that the two genera are indeed related. Judging relationships based on shared characters requires care, since plants may resemble one another through convergent evolution in which characters have arisen independently. Some euphorbias have leafless, rounded bodies adapted to water conservation similar to those of globular cacti, but characters such as the structure of their flowers make it clear that the two groups are not closely related. The cladistic method takes a systematic approach to characters, distinguishing between those that carry no information about shared evolutionary history – such as those evolved separately in different groups (homoplasies) or those left over from ancestors (plesiomorphies) – and derived characters, which have been passed down from innovations in a shared ancestor (apomorphies). Only derived characters, such as the spine-producing areoles of cacti, provide evidence for descent from a common ancestor. The results of cladistic analyses are expressed as cladograms: tree-like diagrams showing the pattern of evolutionary branching and descent. From the 1990s onwards, the predominant approach to constructing phylogenies for living plants has been molecular phylogenetics, which uses molecular characters, particularly DNA sequences, rather than morphological characters like the presence or absence of spines and areoles. The difference is that the genetic code itself is used to decide evolutionary relationships, instead of being used indirectly via the characters it gives rise to. Clive Stace describes this as having "direct access to the genetic basis of evolution." As a simple example, prior to the use of genetic evidence, fungi were thought either to be plants or to be more closely related to plants than animals. Genetic evidence suggests that the true evolutionary relationship of multicelled organisms is as shown in the cladogram below – fungi are more closely related to animals than to plants. In 1998, the Angiosperm Phylogeny Group published a phylogeny for flowering plants based on an analysis of DNA sequences from most families of flowering plants. As a result of this work, many questions, such as which families represent the earliest branches of angiosperms, have now been answered. Investigating how plant species are related to each other allows botanists to better understand the process of evolution in plants. Despite the study of model plants and increasing use of DNA evidence, there is ongoing work and discussion among taxonomists about how best to classify plants into various taxa. Technological developments such as computers and electron microscopes have greatly increased the level of detail studied and speed at which data can be analysed. == Symbols == A few symbols are in current use in botany. A number of others are obsolete; for example, Linnaeus used planetary symbols ⟨♂⟩ (Mars) for biennial plants, ⟨♃⟩ (Jupiter) for herbaceous perennials and ⟨♄⟩ (Saturn) for woody perennials, based on the planets' orbital periods of 2, 12 and 30 years; and Willd used ⟨♄⟩ (Saturn) for neuter in addition to ⟨☿⟩ (Mercury) for hermaphroditic. The following symbols are still used: == See also == == Notes == == References == === Citations === === Sources === == External links == Media related to Botany at Wikimedia Commons
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https://en.wikipedia.org/wiki/Botany
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Science Saru, Inc. (Japanese: 株式会社サイエンスSARU, Hepburn: Kabushiki-gaisha Saiensu SARU), stylized as Science SARU, is a Japanese animation studio headquartered in Kichijōji, Musashino, Tokyo. Established on February 4, 2013, by producer Eunyoung Choi and director Masaaki Yuasa, the studio has produced four feature films and five animated series, as well as co-productions, a compilation film, and episodes of series for other studios. Science Saru's first animation was the "Food Chain" episode of the American animated series Adventure Time (2014); its most recent projects are the animated feature film Inu-Oh (2021), two short films for the animated anthology project Star Wars: Visions (2021), and the animated series The Heike Story (2021), Yurei Deco (2022), Scott Pilgrim Takes Off (2023), and Dandadan (2024). The studio's work has received critical acclaim both within Japan and internationally, winning awards from Annecy, the Japan Academy Film Prize, the Mainichi Film Awards, and the Japan Media Arts Festival. Science Saru utilizes a hybrid animation production method which combines hand-drawn animation and digital animation (including Flash animation), a technique not previously used in Japanese animation. The studio is currently led by Eunyoung Choi. == Name == The studio's name Science Saru translates into English as "Science Monkey". Company co-founder Masaaki Yuasa frequently drew himself as a monkey in self-portraits, but wanted his company to be smarter than a monkey; as a result, he added the word Science in front of Saru with the intent of having a company that possesses both instinct and intelligence. Co-founder Eunyoung Choi further described the meaning behind the name: "We thought about a lot of possible names for the studio... Science is like logic, business, numbers, plans, technology, and new tools. On the other hand, 'Saru' means monkey in Japanese. As animators, we put in creativity, intuition, art, enjoying moments and being playful… a kind of 'monkeying around'. We want to keep these personalities in Science Saru. Thus, we wanted to create a balance. 'Science' is in English, which highlights being international, and 'Saru' in Japanese maintains traditional anime." == History == === Founding === Science Saru was founded on February 4, 2013 by Masaaki Yuasa and Eunyoung Choi. Yuasa and Choi had previously worked together on numerous projects, and Choi had prior experience leading Ankama Japan, a studio which utilized similar digital animation production techniques and employed a multinational staff. The creation of the studio was proposed by Choi during the making of the short film Kick-Heart (2013), which was the first large-scale Japanese animated project to be successfully crowdfunded on Kickstarter. The studio's first official production under the Science Saru name was an episode of the American Adventure Time animated series entitled Food Chain (2014), on which Yuasa worked as director, writer, and storyboard artist; Choi served as co-director. By July 2014, the studio was also recognized for creating the digital animation for Yuasa's animated series Ping Pong the Animation (2014). Science Saru's first production location was a small suburban house converted into an impromptu animation studio. By the end of 2013, the company had expanded to a staff of five, including Yuasa, Choi, and Abel Góngora, a former member of Ankama Japan; the studio's first productions began with this small crew. === Early work as a subcontractor (2014–2015) === Science Saru began its corporate activities by taking on subcontracting work, as well as by collaborating with other studios on projects. The studio's first project was the Adventure Time episode Food Chain (2014). The episode was produced entirely in-house, and Yuasa and Choi were given free rein by series creator Pendleton Ward to develop the episode as they saw fit. Food Chain received critical acclaim as one of the best episodes of the series, was an official competition selection at Annecy, and was nominated for the Annie Award for Outstanding Television Direction. Another early highlight was Yuasa's television series Ping Pong the Animation (2014); Science Saru provided 'digitally assisted' animation production services, while Tatsunoko Production served as the primary studio. The series was awarded a Jury Selection Prize at the Japan Media Arts Festival, and won the Grand Prize for Television Animation at the Tokyo Anime Awards Festival; additionally, character designer and longtime collaborator Nobutake Ito won the Best Animator award for individual achievement. Ping Pong the Animation was subsequently highlighted as one of the best Japanese animated series of the decade. Science Saru also provided production assistance on a pair of episodes of the Bones television series Space Dandy (2014); and both received critical acclaim. Additional subcontracting work included opening credits animation for several of the animated Garo series (2014-15; 2017-18); animation assistance for Yo-kai Watch: The Movie (2014), a pair of Crayon Shin-chan films (2014, 2015), and Typhoon Noruda (2015); and animation production for the promotional mini-series What's Debikuro? (2014), the music video Song of Four Seasons (2015), and promotional episodes for the American animated series OK K.O.!: Let's Be Heroes (2015-17). === Move to feature films (2016–2017) === By early 2016, Science Saru had gained experience and built a name in the industry; while still a small team, the company was ready to undertake its first large-scale project. The studio's first feature film production, the family-friendly fantasy film Lu Over the Wall (2017), was produced in less than 16 months using 'digitally assisted' animation techniques. Yuasa directed and co-wrote Lu Over the Wall; it was his first feature film with an original story. During the production of Lu Over the Wall, Yuasa and Science Saru were offered the opportunity to produce a second feature film, the comedy romance Night Is Short, Walk On Girl (2017), based on the novel by Tomihiko Morimi. Prior to the establishment of Science Saru, Yuasa had directed a television series adaptation of Morimi's novel The Tatami Galaxy (2010); Yuasa had originally hoped to adapt Night is Short, Walk On Girl immediately after that production, but was unable to at the time. When he was offered the opportunity in 2016, he immediately agreed. This resulted in the pre-production work on Night is Short, Walk On Girl overlapping with the post-production of Lu Over the Wall. Although Lu Over the Wall was completed first, it was released after Night is Short, Walk On Girl; this was in part due to a marketing suggestion that it might be preferable for the studio's first film to be based on a pre-existing property familiar to Japanese audiences. Both Lu Over the Wall and Night is Short, Walk On Girl received immediate critical acclaim. Lu Over the Wall received the Annecy Cristal du long métrage, the Mainichi Film Awards' Ōfuji Noburō Award, and the Japan Media Arts Festival Grand Prize for Animation. The Night is Short, Walk On Girl was awarded the Japan Academy Film Prize for Animation of the Year, the Ottawa International Animation Festival Grand Prize for Best Animated Feature, a Jury Selection Prize at the Japan Media Arts Festival, and has been listed as one of the best Japanese animated films of the decade. === International success and Netflix partnership (2018–2019) === 2018 was the year that saw Science Saru, and in particular Masaaki Yuasa, achieve international recognition and prominence. Lu Over the Wall and Night is Short, Walk On Girl, as well as Yuasa's pre-Science Saru feature film Mind Game (2004), were licensed for North American distribution by GKIDS. Most significant to Science Saru's growing popularity was the Netflix release of Yuasa's animated series Devilman Crybaby (2018), based on the manga by Go Nagai. The series represented a dramatic scaling up of Science Saru's production capacity; prior to this project, the company had operated with a limited staff of 20-25 people, but work on the series necessitated expansion, including the hiring of episode directors and new creative talents. Devilman Crybaby was an immediate and massive international hit; with 90% of its viewers outside Japan, the series achieved the largest global audience for the studio to that date. The series inspired internet memes, was profiled by YouTuber PewDiePie, and was widely discussed on Twitter. The series was nominated in 7 categories at the Crunchyroll Anime Awards and won for Anime of the Year and director of the Year, was awarded a Jury Selection Prize at the Japan Media Arts Festival, was cited by Vulture as containing one of the 100 most influential sequences in global animation history, and was listed as one of the best Japanese animated series of the decade. In 2019, Science Saru produced Yuasa's next feature film, the romance Ride Your Wave (2019). An original story, the film earned Science Saru the studio's best reviews to date. Ride Your Wave was an official competition selection at Annecy, was nominated for the Mainichi Film Award for Best Animation Film, was nominated for Annie Awards in the categories of Best Indie Feature and Outstanding Feature Film Direction, received a Jury Selection Prize at the Japan Media Arts Festival, and won Best Animated Feature Film awards at the Shanghai International Film Festival, Fantasia International Film Festival, and Sitges Film Festival. Also in 2019, Science Saru produced the series Super Shiro (2019), an installment of the popular Crayon Shin-chan franchise created by Yoshito Usui. The series was directed by Yuasa and veteran animator Tomohisa Shimoyama (making his directorial debut). Yuasa's involvement was the culmination of a long association with Crayon Shin-chan, having first animated for the franchise in the 1990s. The end of the year saw the 2010s heralded as Masaaki Yuasa's "breakout decade"; collectively, Devilman crybaby and the release of Yuasa's films in the United States led to him being highlighted as one of the most important and exciting directors in animation. In 2020, Science Saru produced the comedy television series Keep Your Hands Off Eizouken! (2020). Directed by Yuasa and based on the manga by Sumito Ōwara, the series boosted sales of the original manga, inspired internet memes, and won the Japanese Broadcast Critics Association's monthly Galaxy Award during its broadcast run. Following the conclusion of the broadcast, Keep Your Hands Off Eizouken! received critical acclaim as one of the best Japanese animated series of both the season that it aired and the year as a whole, and was recognized by The New York Times and The New Yorker as one of the best television series of 2020. The series was nominated in 10 categories at the Crunchyroll Anime Awards and won for Director of the Year and Best Animation, was awarded the Grand Prize for Television Animation at the Tokyo Anime Awards Festival, and received the Japan Media Arts Festival Grand Prize for Animation. Later that year, Science Saru produced the Netflix series Japan Sinks: 2020 (2020), based on the disaster novel by Sakyo Komatsu. Yuasa directed in conjunction with Pyeon-Gang Ho, who made her directorial debut with the series. The series attracted criticism within Japan for its condemnation of Japanese nationalism, but also received positive attention for its multiculturalism and inclusiveness, and was named as one of the best Japanese animated series of 2020. The first episode of the series was awarded the Annecy Jury Prize for a Television Series, and the series as a whole received two nominations at the Crunchyroll Anime Awards. A film compilation version of the series was subsequently released in Japanese theaters in November 2020, and was awarded a Jury Selection Prize at the Japan Media Arts Festival. === New CEO and COVID-19 (2020–2023) === On March 25, 2020, Masaaki Yuasa stepped down as president and representative director of Science Saru. Yuasa cited his desire to take a rest from directing after seven years of continuous work, but reaffirmed his commitment to completing additional projects with Science Saru in the future. Eunyoung Choi subsequently became CEO and president of the studio. She likewise affirmed Yuasa's continued involvement with the company as a creator, and noted that the studio will look to develop additional projects with other directors. During the 2020 COVID-19 pandemic, Science Saru was able to adjust quickly and continue production, despite much of the Japanese animation industry being affected. In October 2020, Science Saru entered into a non-exclusive strategic partnership with Netflix covering the development of new series and content. In early 2021, Yuasa was recognized by the Japanese government's Agency for Cultural Affairs, which awarded him the Cabinet Minister Award for Media Fine Arts for his significant career achievements with Science Saru, as well as for his works prior to establishing the studio. Later that year, Yuasa was further recognized with the Medal of Honor with Purple Ribbon by the Japanese government in recognition of his distinguished contributions to artistic and cultural development. In fall 2021, Science Saru released a pair of interrelated projects: the Masaaki Yuasa feature film Inu-Oh (2021), and the animated television series The Heike Story (2021). Based on the novel by Hideo Furukawa and featuring character designs by Ping Pong creator Taiyō Matsumoto, Inu-Oh is a musical drama film set during the 14th Century in Japan which centers on the unique and unexpected friendship between two traveling Noh performers. The film premiered at the 78th Venice International Film Festival on September 9, 2021, with a worldwide theatrical release to follow in 2022. The film was licensed for North American theatrical and home-video distribution by GKIDS, and was released in US theaters in August 2022. Upon its debut on the international festival circuit, Inu-Oh received immediately critical acclaim and excellent reviews from international critics, was nominated for the Golden Globe Award for Best Animated Feature Film, and won the Mainichi Film Awards' Ōfuji Noburō Award and the Best Animated Feature Film award at the Fantasia International Film Festival. Produced simultaneously with Inu-Oh, the television series The Heike Story adapts author Hideo Furukawa's translation of the epic ancient Japanese historical narrative The Tale of the Heike. The series was directed by Naoko Yamada and focuses on both the politics and devastation of the Genpei War, a cataclysmic civil war in the 12th Century that divided Japan, and the personal lives and tragedies of the women of both warring clans who are caught up in the conflict. The series premiered on September 15, 2021 in North America on the Funimation streaming service, with premieres the following day on the Japanese streaming service FOD (operated by Fuji TV) and the Chinese streaming service Bilibili; a Japanese television broadcast on Fuji TV's +Ultra programming block followed in January 2022. Following the conclusion of its streaming release, The Heike Story was named one of the best series of 2021, and was nominated in 3 categories for the 2022 Anime Trending Awards. Additionally, in September 2021, Science Saru produced two short films for the animated anthology project Star Wars: Visions (2021). The shorts, entitled Akakiri and T0-B1, were part of a nine-film anthology of shorts, all of which premiered on September 22 worldwide on Disney+. Akakiri was directed by Eunyoung Choi and centers on the story of a princess and a Jedi, while T0-B1 was directed by Abel Góngora and follows the adventures of a droid who dreams of becoming a Jedi and exploring the galaxy. The anthology as a whole received stellar reviews, with Science Saru's films highlighted as particular standouts. Star Wars: Visions was heralded as one of the best animated projects of the year, as well as one of the best Star Wars titles in a decade or more. Episodes of the anthology project were also nominated for multiple awards. In 2022, Science Saru released the original television animation series Yurei Deco. Directed by Tomohisa Shimoyama, written by Dai Satō, and based on a concept by Masaaki Yuasa, the series drew inspiration from Mark Twain's The Adventures of Huckleberry Finn and premiered to excellent reviews. Science Saru's following project was an animated adaptation of the novel Tatami Time Machine Blues. Based on the novel of the same name written by Tomihiko Morimi and derived from a concept by Makoto Ueda, Tatami Time Machine Blues serves as a sequel to The Tatami Galaxy, which Yuasa adapted as a television series in April 2010, prior to the establishment of Science Saru. The project was directed by Shingo Natsume, while screenwriter Makoto Ueda, character designer Yusuke Nakamura, and the majority of the original Japanese voice cast reprise their creative roles from The Tatami Galaxy. The project initially debuted as a series on Disney+ in 2022, with a theatrical compilation film following later that year; the Disney+ release included an original episode that was not part of the theatrical compilation. === Toho subsidiary (2024–present) === On May 23, 2024, it was announced that Toho would buy all of Science SARU's shares and make it a subsidiary, which was completed by June 19 the same year. == Style and studio environment == Science Saru utilizes a combination of traditional hand drawn animation and digital animation created using multiple software programs, including Adobe Animate. The studio refers to its animation production method and resultant style as 'digitally assisted animation.' When utilizing 'digitally assisted animation', the initial animation work, called key animation (where the key poses of movement are established), is drawn by hand, and then recreated digitally for the stages of inbetween animation (used to create smooth movement by filling in the gaps between keyframe poses), as well as for coloring. The advantage of this production technique is increased efficiency, allowing projects to be completed faster and with a smaller crew; the small team focus allows for a strong understanding of the director's artistic vision. This approach to animation production has won praise from creators and industry publications. Science Saru's diversity is also unique among Japanese animation studios: it employs a multicultural animation staff. According to Choi, staff are chosen based on skill regardless of national origin, and the inclusion of global perspectives helps create more well-rounded stories. == Feature films == For the purposes of the list below, all films and series upon which Science Saru worked are listed. Titles which Science Saru produced or co-produced are shaded in grey; titles for which the studio served as a subcontractor are shaded in yellow. == Animated series == For the purposes of the list below, all films and series upon which Science Saru worked are listed. Titles which Science Saru produced or co-produced are shaded in grey; titles for which the studio served as a subcontractor are shaded in yellow. == Awards and acclaim == Science Saru's projects have received significant global acclaim. The studio's works have been recognized by the Annecy International Animated Film Festival (2 wins, 2 nominations), the Japan Academy Film Prize Association (1 win), the Golden Globe Awards (1 nomination), the Mainichi Film Awards (2 wins, 1 nomination), the Japan Media Arts Festival (2 wins, 5 jury selections), the Tokyo Anime Awards (3 wins), the Crunchyroll Anime Awards (4 wins, 16 nominations), the Ottawa International Animation Festival (1 win, 1 nomination), the Shanghai International Film Festival (1 win, 1 nomination) the Sitges Film Festival (1 win, 2 nominations), the Fantasia International Film Festival (2 wins, 1 silver, 1 bronze), the Satellite Awards (1 nomination), and the Annie Awards (3 nominations). == Staff == === Current company members === Eunyoung Choi (Founder, President & CEO) Abel Góngora (Creative Team Director, Flash Animation Chief) === Associated creators === Masaaki Yuasa (Founder, Director) Tomohisa Shimoyama (Director) Naoko Yamada (Director) == References == == External links == Official website (in Japanese) Science Saru at Anime News Network's encyclopedia
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https://en.wikipedia.org/wiki/Science_Saru
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In mathematics and empirical science, quantification (or quantitation) is the act of counting and measuring that maps human sense observations and experiences into quantities. Quantification in this sense is fundamental to the scientific method. == Natural science == Some measure of the undisputed general importance of quantification in the natural sciences can be gleaned from the following comments: "these are mere facts, but they are quantitative facts and the basis of science." It seems to be held as universally true that "the foundation of quantification is measurement." There is little doubt that "quantification provided a basis for the objectivity of science." In ancient times, "musicians and artists ... rejected quantification, but merchants, by definition, quantified their affairs, in order to survive, made them visible on parchment and paper." Any reasonable "comparison between Aristotle and Galileo shows clearly that there can be no unique lawfulness discovered without detailed quantification." Even today, "universities use imperfect instruments called 'exams' to indirectly quantify something they call knowledge." This meaning of quantification comes under the heading of pragmatics. In some instances in the natural sciences a seemingly intangible concept may be quantified by creating a scale—for example, a pain scale in medical research, or a discomfort scale at the intersection of meteorology and human physiology such as the heat index measuring the combined perceived effect of heat and humidity, or the wind chill factor measuring the combined perceived effects of cold and wind. == Social sciences == In the social sciences, quantification is an integral part of economics and psychology. Both disciplines gather data – economics by empirical observation and psychology by experimentation – and both use statistical techniques such as regression analysis to draw conclusions from it. In some instances a seemingly intangible property may be quantified by asking subjects to rate something on a scale—for example, a happiness scale or a quality-of-life scale—or by the construction of a scale by the researcher, as with the index of economic freedom. In other cases, an unobservable variable may be quantified by replacing it with a proxy variable with which it is highly correlated—for example, per capita gross domestic product is often used as a proxy for standard of living or quality of life. Frequently in the use of regression, the presence or absence of a trait is quantified by employing a dummy variable, which takes on the value 1 in the presence of the trait or the value 0 in the absence of the trait. Quantitative linguistics is an area of linguistics that relies on quantification. For example, indices of grammaticalization of morphemes, such as phonological shortness, dependence on surroundings, and fusion with the verb, have been developed and found to be significantly correlated across languages with stage of evolution of function of the morpheme. == Hard versus soft science == The ease of quantification is one of the features used to distinguish hard and soft sciences from each other. Scientists often consider hard sciences to be more scientific or rigorous, but this is disputed by social scientists who maintain that appropriate rigor includes the qualitative evaluation of the broader contexts of qualitative data. In some social sciences such as sociology, quantitative data are difficult to obtain, either because laboratory conditions are not present or because the issues involved are conceptual but not directly quantifiable. Thus in these cases qualitative methods are preferred. == See also == Calibration Internal standard Isotope dilution Physical quantity Quantitative analysis (chemistry) Standard addition == References == == Further reading == Crosby, Alfred W. (1996) The Measure of Reality: Quantification and Western Society, 1250–1600. Cambridge University Press. Wiese, Heike, 2003. Numbers, Language, and the Human Mind. Cambridge University Press. ISBN 0-521-83182-2.
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https://en.wikipedia.org/wiki/Quantification_(science)
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Astrology consists of a number of belief systems that hold that there is a relationship between astronomical phenomena and events or descriptions of personality in the human world. Astrology has been rejected by the scientific community as having no explanatory power for describing the universe. Scientific testing has found no evidence to support the premises or purported effects outlined in astrological traditions. Where astrology has made falsifiable predictions, it has been falsified.: 424 The most famous test was headed by Shawn Carlson and included a committee of scientists and a committee of astrologers. It led to the conclusion that natal astrology performed no better than chance. Astrology has not demonstrated its effectiveness in controlled studies and has no scientific validity,: 85 and is thus regarded as pseudoscience.: 1350 There is no proposed mechanism of action by which the positions and motions of stars and planets could affect people and events on Earth in the way astrologers say they do that does not contradict well-understood, basic aspects of biology and physics.: 249 Although astrology has no scientific validity, astrological beliefs have impacted human history and astrology has helped to drive the development of astronomy. Modern scientific inquiry into astrology is primarily focused on drawing a correlation between astrological traditions and the influence of seasonal birth in humans. == Introduction == The majority of professional astrologers rely on performing astrology-based personality tests and making relevant predictions about the remunerator's future.: 83 Those who continue to have faith in astrology have been characterised as doing so "in spite of the fact that there is no verified scientific basis for their beliefs, and indeed that there is strong evidence to the contrary". Astrophysicist Neil deGrasse Tyson commented on astrological belief, saying that "part of knowing how to think is knowing how the laws of nature shape the world around us. Without that knowledge, without that capacity to think, you can easily become a victim of people who seek to take advantage of you". The continued belief in astrology despite its lack of credibility is seen as a demonstration of low scientific literacy, although some continue to believe in it even though they are scientifically literate. == Historical relationship with astronomy == The foundations of the theoretical structure used in astrology originate with the Babylonians, although widespread usage did not occur until the start of the Hellenistic period after Alexander the Great swept through Greece. It was not known to the Babylonians that the constellations are not on a celestial sphere and are very far apart. The appearance of them being close is illusory. The exact demarcation of what a constellation is is cultural and varied between civilisations.: 62 Ptolemy's work on astronomy was driven to some extent by the desire, like all astrologers of the time, to easily calculate the planetary movements.: 40 Early Western astrology operated under the Ancient Greek concepts of the Macrocosm and microcosm, and thus medical astrology related what happened to the planets and other objects in the sky to medical operations. This provided a further motivator for the study of astronomy.: 73 While still defending the practice of astrology, Ptolemy acknowledged that the predictive power of astronomy for the motion of the planets and other celestial bodies ranked above astrological predictions.: 344 During the Islamic Golden Age, astronomy was funded so that the astronomical parameters, such as the eccentricity of the sun's orbit, required for the Ptolemaic model could be calculated to sufficient accuracy and precision. Those in positions of power, like the Fatimid Caliphate vizier in 1120, funded the construction of observatories so that astrological predictions, fuelled by precise planetary information, could be made.: 55–56 Since the observatories were built to help in making astrological predictions, few of these observatories lasted long due to the prohibition against astrology within Islam, and most were torn down during or just after construction.: 57 The clear rejection of astrology in works of astronomy started in 1679, with the yearly publication La Connoissance des temps.: 220 Unlike the West, in Iran, the rejection of heliocentrism continued up towards the start of the 20th century, in part motivated by a fear that this would undermine the widespread belief in astrology and Islamic cosmology in Iran.: 10 The first work, Falak al-sa'ada by Ictizad al-Saltana, aimed at undermining this belief in astrology and "old astronomy" in Iran was published in 1861. On astrology, it cited the inability of different astrologers to make the same prediction about what occurs following a conjunction and described the attributes astrologers gave to the planets as implausible.: 17–18 == Philosophy of science == Astrology provides the quintessential example of a pseudoscience since it has been tested repeatedly and failed all the tests.: 62 === Falsifiability === Science and non-science are often distinguished by the criterion of falsifiability. The criterion was first proposed by philosopher of science Karl Popper. To Popper, science does not rely on induction; instead, scientific investigations are inherently attempts to falsify existing theories through novel tests. If a single test fails, then the theory is falsified.: 10 Therefore, any test of a scientific theory must prohibit certain results that falsify the theory, and expect other specific results consistent with the theory. Using this criterion of falsifiability, astrology is a pseudoscience. Astrology was Popper's most frequent example of pseudoscience.: 7 Popper regarded astrology as "pseudo-empirical" in that "it appeals to observation and experiment", but "nevertheless does not come up to scientific standards".: 44 In contrast to scientific disciplines, astrology does not respond to falsification through experiment. According to Professor of neurology Terence Hines, this is a hallmark of pseudoscience.: 206 === "No puzzles to solve" === In contrast to Popper, the philosopher Thomas Kuhn argued that it was not lack of falsifiability that makes astrology unscientific, but rather that the process and concepts of astrology are non-empirical.: 401 To Kuhn, although astrologers had, historically, made predictions that "categorically failed", this in itself does not make it unscientific, nor do the attempts by astrologers to explain away the failure by claiming it was due to the creation of a horoscope being very difficult (through subsuming, after the fact, a more general horoscope that leads to a different prediction). Rather, in Kuhn's eyes, astrology is not science because it was always more akin to medieval medicine; they followed a sequence of rules and guidelines for a seemingly necessary field with known shortcomings, but they did no research because the fields are not amenable to research,: 8 and so, "They had no puzzles to solve and therefore no science to practise.": 8 : 401 While an astronomer could correct for failure, an astrologer could not. An astrologer could only explain away failure but could not revise the astrological hypothesis in a meaningful way. As such, to Kuhn, even if the stars could influence the path of humans through life astrology is not scientific.: 8 === Progress, practice and consistency === Philosopher Paul Thagard believed that astrology can not be regarded as falsified in this sense until it has been replaced with a successor. In the case of predicting behaviour, psychology is the alternative.: 228 To Thagard a further criterion of demarcation of science from pseudoscience was that the state of the art must progress and that the community of researchers should be attempting to compare the current theory to alternatives, and not be "selective in considering confirmations and disconfirmations".: 227–228 Progress is defined here as explaining new phenomena and solving existing problems, yet astrology has failed to progress having only changed little in nearly 2000 years.: 228 : 549 To Thagard, astrologers are acting as though engaged in normal science believing that the foundations of astrology were well established despite the "many unsolved problems", and in the face of better alternative theories (Psychology). For these reasons Thagard viewed astrology as pseudoscience.: 228 To Thagard, astrology should not be regarded as a pseudoscience on the failure of Gauquelin to find any correlation between the various astrological signs and someone's career, twins not showing the expected correlations from having the same signs in twin studies, lack of agreement on the significance of the planets discovered since Ptolemy's time and large scale disasters wiping out individuals with vastly different signs at the same time.: 226–227 Rather, his demarcation of science requires three distinct foci: "theory, community [and] historical context". While verification and falsifiability focused on the theory, Kuhn's work focused on the historical context, but the astrological community should also be considered. Whether or not they:: 226–227 are focused on comparing their approach to others. have a consistent approach. try to falsify their theory through experiment. In this approach, true falsification rather than modifying a theory to avoid the falsification only really occurs when an alternative theory is proposed.: 228 === Irrationality === For the philosopher Edward W. James, astrology is irrational not because of the numerous problems with mechanisms and falsification due to experiments, but because an analysis of the astrological literature shows that it is infused with fallacious logic and poor reasoning.: 34 What if throughout astrological writings we meet little appreciation of coherence, blatant insensitivity to evidence, no sense of a hierarchy of reasons, slight command over the contextual force of critieria, stubborn unwillingness to pursue an argument where it leads, stark naivete concerning the efficacy of explanation and so on? In that case, I think, we are perfectly justified in rejecting astrology as irrational. ... Astrology simply fails to meet the multifarious demands of legitimate reasoning. This poor reasoning includes appeals to ancient astrologers such as Kepler despite any relevance of topic or specific reasoning, and vague claims. The claim that evidence for astrology is that people born at roughly "the same place have a life pattern that is very similar" is vague, but also ignores that time is reference frame dependent and gives no definition of "same place" despite the planet's moving in the reference frame of the Solar System. Other comments by astrologers are based on severely erroneous interpretations of basic physics, such as the general belief by medieval astrologers that the geocentric Solar System corresponded to an atom. Further, James noted that response to criticism also relies on faulty logic, an example of which was a response to twin studies with the statement that coincidences in twins are due to astrology, but any differences are due to "heredity and environment", while for other astrologers the issues are too difficult and they just want to get back to their astrology.: 32 Further, to astrologers, if something appears in their favour, they may latch upon it as proof, while making no attempt to explore its implications, preferring to refer to the item in favour as definitive; possibilities that do not make astrology look favourable are ignored.: 33 === Quinean dichotomy === From the Quinean web of knowledge, there is a dichotomy where one must either reject astrology or accept astrology but reject all established scientific disciplines that are incompatible with astrology.: 24 == Tests of astrology == Astrologers often do not make verifiable predictions, but instead make vague statements that are not falsifiable.: 48–49 Across several centuries of testing, the predictions of astrology have never been more accurate than that expected by chance alone. One approach used in testing astrology quantitatively is through blind experiment. When specific predictions from astrologers were tested in rigorous experimental procedures in the Carlson test, the predictions were falsified. All controlled experiments have failed to show any effect.: 24 === Mars effect === In 1955, astrologer and psychologist Michel Gauquelin stated that although he had failed to find evidence to support such indicators as the zodiacal signs and planetary aspects in astrology, he had found positive correlations between the diurnal positions of some of the planets and success in professions (such as doctors, scientists, athletes, actors, writers, painters, etc.), which astrology traditionally associates with those planets. The best-known of Gauquelin's findings is based on the positions of Mars in the natal charts of successful athletes and became known as the "Mars effect".: 213 A study conducted by seven French scientists attempted to replicate the claim, but found no statistical evidence.: 213–214 They attributed the effect to selective bias on Gauquelin's part, accusing him of attempting to persuade them to add or delete names from their study. Geoffrey Dean has suggested that the effect may be caused by self-reporting of birth dates by parents rather than any issue with the study by Gauquelin. The suggestion is that a small subset of the parents may have had changed birth times to be consistent with better astrological charts for a related profession. The sample group was taken from a time where belief in astrology was more common. Gauquelin had failed to find the Mars effect in more recent populations, where a nurse or doctor recorded the birth information. The number of births under astrologically undesirable conditions was also lower, indicating more evidence that parents choose dates and times to suit their beliefs.: 116 === Carlson's experiment === Shawn Carlson's now renowned experiment was performed by 28 astrologers matching over 100 natal charts to psychological profiles generated by the California Psychological Inventory (CPI) test using double blind methods. The experimental protocol used in Carlson's study was agreed to by a group of physicists and astrologers prior to the experiment. Astrologers, nominated by the National Council for Geocosmic Research, acted as the astrological advisors, and helped to ensure, and agreed, that the test was fair.: 117 : 420 They also chose 26 of the 28 astrologers for the tests, the other two being interested astrologers who volunteered afterwards.: 420 The astrologers came from Europe and the United States.: 117 The astrologers helped to draw up the central proposition of natal astrology to be tested.: 419 Published in Nature in 1985, the study found that predictions based on natal astrology were no better than chance, and that the testing "clearly refutes the astrological hypothesis". === Dean and Kelly === Scientist and former astrologer Geoffrey Dean and psychologist Ivan Kelly conducted a large-scale scientific test, involving more than one hundred cognitive, behavioural, physical and other variables, but found no support for astrology. A further test involved 45 confident astrologers, with an average of 10 years' experience and 160 test subjects (out of an original sample size of 1198 test subjects) who strongly favoured certain characteristics in the Eysenck Personality Questionnaire to extremes.: 191 The astrologers performed much worse than merely basing decisions off the individuals' ages, and much worse than 45 control subjects who did not use birth charts at all.: 191 === Other tests === A meta-analysis was conducted, pooling 40 studies consisting of 700 astrologers and over 1,000 birth charts. Ten of the tests, which had a total of 300 participating, involved the astrologers picking the correct chart interpretation out of a number of others that were not the astrologically correct chart interpretation (usually three to five others). When the date and other obvious clues were removed, no significant results were found to suggest there was any preferred chart.: 190 In 10 studies, participants picked horoscopes that they felt were accurate descriptions, with one being the "correct" answer. Again the results were no better than chance.: 66–67 In a study of 2011 sets of people born within 5 minutes of each other ("time twins") to see if there was any discernible effect; no effect was seen.: 67 Quantitative sociologist David Voas examined the census data for more than 20 million individuals in England and Wales to see if star signs corresponded to marriage arrangements. No effect was seen.: 67 == Theoretic obstacles == Beyond the scientific tests astrology has failed, proposals for astrology face a number of other obstacles due to the many theoretical flaws in astrology: 62 : 24 including lack of consistency, lack of ability to predict missing planets, lack of connection of the zodiac to the constellations in Western astrology, and lack of any plausible mechanism. The underpinnings of astrology tend to disagree with numerous basic facts from scientific disciplines.: 24 === Lack of consistency === Testing the validity of astrology can be difficult because there is no consensus amongst astrologers as to what astrology is or what it can predict.: 83 Dean and Kelly documented 25 studies, which had found that the degree of agreement amongst astrologers' predictions was measured as a low 0.1.: 66 Most professional astrologers are paid to predict the future or describe a person's personality and life, but most horoscopes only make vague untestable statements that can apply to almost anyone.: 83 Georges Charpak and Henri Broch dealt with claims from Western astrology in the book Debunked! ESP, Telekinesis, and other Pseudoscience. They pointed out that astrologers have only a small knowledge of astronomy and that they often do not take into account basic features such as the precession of the equinoxes. They commented on the example of Elizabeth Teissier who claimed that "the sun ends up in the same place in the sky on the same date each year" as the basis for claims that two people with the same birthday but a number of years apart should be under the same planetary influence. Charpak and Broch noted that "there is a difference of about twenty-two thousand miles between Earth's location on any specific date in two successive years" and that thus they should not be under the same influence according to astrology. Over a 40 years period there would be a difference greater than 780,000 miles.: 6–7 === Lack of physical basis === Edward W. James, commented that attaching significance to the constellation on the celestial sphere the sun is in at sunset was done on the basis of human factors—namely, that astrologers did not want to wake up early, and the exact time of noon was hard to know. Further, the creation of the zodiac and the disconnect from the constellations was because the sun is not in each constellation for the same amount of time.: 25 This disconnection from the constellations led to the problem with precession separating the zodiac symbols from the constellations that they once were related to.: 26 Philosopher of science, Massimo Pigliucci commenting on the movement, opined "Well then, which sign should I look up when I open my Sunday paper, I wonder?": 64 The tropical zodiac has no connection to the stars, and as long as no claims are made that the constellations themselves are in the associated sign, astrologers avoid the concept that precession seemingly moves the constellations because they do not reference them. Charpak and Broch, noting this, referred to astrology based on the tropical zodiac as being "...empty boxes that have nothing to do with anything and are devoid of any consistency or correspondence with the stars." Sole use of the tropical zodiac is inconsistent with references made, by the same astrologers, to the Age of Aquarius, which depends on when the vernal point enters the constellation of Aquarius. === Lack of predictive power === Some astrologers make claims that the position of all the planets must be taken into account, but astrologers were unable to predict the existence of Neptune based on mistakes in horoscopes. Instead Neptune was predicted using Newton's law of universal gravitation. The grafting on of Uranus, Neptune and Pluto into the astrology discourse was done on an ad hoc basis. On the demotion of Pluto to the status of dwarf planet, Philip Zarka of the Paris Observatory in Meudon, France wondered how astrologers should respond: Should astrologers remove it from the list of luminars [Sun, Moon and the 8 planets other than earth] and confess that it did not actually bring any improvement? If they decide to keep it, what about the growing list of other recently discovered similar bodies (Sedna, Quaoar. etc), some of which even have satellites (Xena, 2003EL61)? === Lack of mechanism === Astrology has been criticised for failing to provide a physical mechanism that links the movements of celestial bodies to their purported effects on human behaviour. In a lecture in 2001, Stephen Hawking stated "The reason most scientists don't believe in astrology is because it is not consistent with our theories that have been tested by experiment." In 1975, amid increasing popular interest in astrology, The Humanist magazine presented a rebuttal of astrology in a statement put together by Bart J. Bok, Lawrence E. Jerome, and Paul Kurtz. The statement, entitled "Objections to Astrology", was signed by 186 astronomers, physicists and leading scientists of the day. They said that there is no scientific foundation for the tenets of astrology and warned the public against accepting astrological advice without question. Their criticism focused on the fact that there was no mechanism whereby astrological effects might occur: We can see how infinitesimally small are the gravitational and other effects produced by the distant planets and the far more distant stars. It is simply a mistake to imagine that the forces exerted by stars and planets at the moment of birth can in any way shape our futures. Astronomer Carl Sagan declined to sign the statement. Sagan said he took this stance not because he thought astrology had any validity, but because he thought that the tone of the statement was authoritarian, and that dismissing astrology because there was no mechanism (while "certainly a relevant point") was not in itself convincing. In a letter published in a follow-up edition of The Humanist, Sagan confirmed that he would have been willing to sign such a statement had it described and refuted the principal tenets of astrological belief. This, he argued, would have been more persuasive and would have produced less controversy. The use of poetic imagery based on the concepts of the macrocosm and microcosm, "as above so below" to decide meaning such as Edward W. James' example of "Mars above is red, so Mars below means blood and war", is a false cause fallacy.: 26 Many astrologers claim that astrology is scientific. If one were to attempt to try to explain it scientifically, there are only four fundamental forces (conventionally), limiting the choice of possible natural mechanisms.: 65 Some astrologers have proposed conventional causal agents such as electromagnetism and gravity. The strength of these forces drops off with distance.: 65 Scientists reject these proposed mechanisms as implausible since, for example, the magnetic field, when measured from Earth, of a large but distant planet such as Jupiter is far smaller than that produced by ordinary household appliances. Astronomer Phil Plait noted that in terms of magnitude, the Sun is the only object with an electromagnetic field of note, but astrology isn't based just off the Sun alone.: 65 While astrologers could try to suggest a fifth force, this is inconsistent with the trends in physics with the unification of electromagnetism and the weak force into the electroweak force. If the astrologer insisted on being inconsistent with the current understanding and evidential basis of physics, that would be an extraordinary claim.: 65 It would also be inconsistent with the other forces which drop off with distance.: 65 If distance is irrelevant, then, logically, all objects in space should be taken into account.: 66 Carl Jung sought to invoke synchronicity, the claim that two events have some sort of acausal connection, to explain the lack of statistically significant results on astrology from a single study he conducted. However, synchronicity itself is considered neither testable nor falsifiable. The study was subsequently heavily criticised for its non-random sample and its use of statistics and also its lack of consistency with astrology. == Psychology == Psychological studies have not found any robust relationship between astrological signs and life outcomes. For example, a study showed that zodiac signs are no more effective than random numbers in predicting subjective well-being and quality of life. It has also been shown that confirmation bias is a psychological factor that contributes to belief in astrology.: 344 : 180–181 : 42–48 Confirmation bias is a form of cognitive bias.: 553 From the literature, astrology believers often tend to selectively remember those predictions that turned out to be true and do not remember those that turned out false. Another, separate, form of confirmation bias also plays a role, where believers often fail to distinguish between messages that demonstrate special ability and those that do not.: 180–181 Thus there are two distinct forms of confirmation bias that are under study with respect to astrological belief.: 180–181 The Barnum effect is the tendency for an individual to give a high accuracy rating to a description of their personality that supposedly tailored specifically for them, but is, in fact, vague and general enough to apply to a wide range of people. If more information is requested for a prediction, the more accepting people are of the results.: 344 In 1949 Bertram Forer conducted a personality test on students in his classroom.: 344 Each student was given a supposedly individual assessment but actually all students received the same assessment. The personality descriptions were taken from a book on astrology. When the students were asked to comment on the accuracy of the test, more than 40% gave it the top mark of 5 out of 5, and the average rating was 4.2.: 134, 135 The results of this study have been replicated in numerous other studies.: 382 The study of the Barnum/Forer effect has been focused mostly on the level of acceptance of fake horoscopes and fake astrological personality profiles.: 382 Recipients of these personality assessments consistently fail to distinguish between common and uncommon personality descriptors.: 383 In a study by Paul Rogers and Janice Soule (2009), which was consistent with previous research on the issue, it was found that those who believed in astrology are generally more susceptible to giving more credence to the Barnum profile than sceptics.: 393 By a process known as self-attribution, it has been shown in numerous studies that individuals with knowledge of astrology tend to describe their personalities in terms of traits compatible with their sun signs. The effect is heightened when the individuals were aware that the personality description was being used to discuss astrology. Individuals who were not familiar with astrology had no such tendency. == Sociology == In 1953, sociologist Theodor W. Adorno conducted a study of the astrology column of a Los Angeles newspaper as part of a project that examined mass culture in capitalist society.: 326 Adorno believed that popular astrology, as a device, invariably led to statements that encouraged conformity—and that astrologers who went against conformity with statements that discouraged performance at work etc. risked losing their jobs.: 327 Adorno concluded that astrology was a large-scale manifestation of systematic irrationalism, where flattery and vague generalisations subtly led individuals to believe the author of the column addressed them directly. Adorno drew a parallel with the phrase opium of the people, by Karl Marx, by commenting, "Occultism is the metaphysic of the dopes.": 329 False balance is where a false, unaccepted or spurious viewpoint is included alongside a well reasoned one in media reports and TV appearances and as a result the false balance implies "there were two equal sides to a story when clearly there were not". During Wonders of the Solar System, a TV programme by the BBC, the physicist Brian Cox said: "Despite the fact that astrology is a load of rubbish, Jupiter can in fact have a profound influence on our planet. And it's through a force... gravity." This upset believers in astrology who complained that there was no astrologer to provide an alternative viewpoint. Following the complaints of astrology believers, Cox gave the following statement to the BBC: "I apologise to the astrology community for not making myself clear. I should have said that this new age drivel is undermining the very fabric of our civilisation." In the programme Stargazing Live, Cox further commented by saying: "in the interests of balance on the BBC, yes astrology is nonsense." In an editorial in the medical journal BMJ, editor Trevor Jackson cited this incident showing where false balance could occur. Studies and polling have shown that the belief in astrology is higher in Western countries than might otherwise be expected. In 2012, in polls 42% of Americans said they thought astrology was at least partially scientific.: 7/25 This belief decreased with education and education is highly correlated with levels of scientific knowledge.: 345 Some of the reported belief levels are due to a confusion of astrology with astronomy (the scientific study of celestial objects). The closeness of the two words varies depending on the language.: 344, 346 A plain description of astrology as an "occult influence of stars, planets etc. on human affairs" had no impact on the general public's assessment of whether astrology is scientific or not in a 1992 eurobarometer poll. This may partially be due to the implicit association amongst the general public, of any wording ending in "-ology" with a legitimate field of knowledge.: 346 In Eurobarometers 224 and 225 performed in 2004, a split poll was used to isolate confusion over wording. In half of the polls, the word "astrology" was used, while in the other the word "horoscope" was used.: 349 Belief that astrology was at least partially scientific was 76%, but belief that horoscopes were at least partially scientific was 43%. In particular, belief that astrology was very scientific was 26% while that of horoscopes was 7%.: 352 This appeared to indicate that the high level of apparent polling support for astrology in the EU was indeed due to confusion over terminology.: 362 == See also == List of topics characterized as pseudoscience Religion and science == Notes == == References == == External links == Merrifield, Michael. "Right Ascension & Declination". Sixty Symbols. Brady Haran for the University of Nottingham.—which also discusses ascension and declination errors in different systems of astrology Smit, Rudolf H. "Astrology and science". An archive of evidence-based studies Fraknoi, Andrew. "An Astronomer Looks at Astrology". A skeptical examination of astrology for beginners
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https://en.wikipedia.org/wiki/Astrology_and_science
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Science and Industry is a multiplayer, teamplay mod for the video game Half-Life. It is one of the oldest Half-Life mods and has been described as a classic mod. The current version of the game is 1.4 beta 14, released on January 19, 2019. The game was first publicly released on July 31, 1999, as version 0.94. == Gameplay == Players assume the role of a security guard for one of two fictional corporations Amalgamated Fluorodynamics (AFD) and Midland Carbide Labs (MCL). The main objective on the standard map type is to capture enemy scientists (who are non-player characters) while defending your own. This is accomplished by locating your enemies research labs, hitting one of the scientists there over the head with your briefcase and then taking him back to your company's administrator. Additional scientists increase the rate of a company's income which can be considered the team's score. Scientists also research new weapons, implants, armor upgrades and devices for their company. Each time a new technology is completed, players vote for the next one to be researched. Players spawn in the "Cloning Facilities" of their company, where they can find weapons and ammo crates, as well as health and armor chargers. At the start of the game, the only weapons available are a briefcase and a pistol, but this arsenal grows bigger as new weapons are researched by the scientists. Players decide which technology to research next by voting for it. The available technologies are divided in 5 branches: Weapons, Armor, Implants, Devices and Process Upgrades. Players decide to either defend their company or attack the other company. Attacking consists mainly of reaching the other company's laboratories, grabbing a scientist by knocking him out with the briefcase, and carrying back to the administrator. If a player dies while carrying a scientist, the scientist stays on the ground unconscious for a limited amount of time before teleporting back to his laboratories. During that time the original carrier or one of his teammates can pick up the scientist again. Some maps feature alternative objectives such as stealing resources (discs, biospecimen) or breaking computers. Defending requires protecting the company's laboratories, this is usually done by defending key areas (entries to the laboratories), killing intruders, and defending unconscious scientists. === Objectives === A standard game lasts 30 minutes. The company with the most money at the end wins. The main way to earn money is to have more scientists than the enemy. Each company starts with three scientists, so a company is making more money than the enemy corporation if it employs at least 4 scientists. So the team with more scientists wins. Some maps feature other objectives than capturing and protecting scientists. A first kind of alternative objective is breakables: these are computers or machinery that can be broken and cost money to replace. A second kind of alternative objective is resources: these are computer discs or research specimen that can be stolen and give a cash bonus. Players also cost money to their company each time they die, since cloning them back to life is not free. == Reception == Science and Industry has received praise for the quality of its maps and unique weapons, but with some criticism over patchy online play. == See also == List of Half-Life mods == References == == External links == Science and Industry official homepage
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https://en.wikipedia.org/wiki/Science_and_Industry
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A Bachelor of Science (BS, BSc, B.S., B.Sc., SB, or ScB; from the Latin scientiae baccalaureus) is a bachelor's degree that is awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University of London in 1860. In the United States, the Lawrence Scientific School first conferred the degree in 1851, followed by the University of Michigan in 1855. Nathaniel Shaler, who was Harvard's Dean of Sciences, wrote in a private letter that "the degree of Bachelor of Science came to be introduced into our system through the influence of Louis Agassiz, who had much to do in shaping the plans of this School.": 48 Whether Bachelor of Science or Bachelor of Arts degrees are awarded in particular subjects varies between universities. For example, an economics student may graduate as a Bachelor of Arts in one university but as a Bachelor of Science in another, and occasionally, both options are offered. Some universities follow the Oxford and Cambridge tradition that even graduates in mathematics and the sciences become Bachelors of Arts, while other institutions offer only the Bachelor of Science degree, even in non-science fields. At universities that offer both Bachelor of Arts and Bachelor of Science degrees in the same discipline, the Bachelor of Science degree is usually more focused on that particular discipline and is targeted toward students intending to pursue graduate school or a profession in that discipline. == International differences == In some institutions, there are historical and traditional reasons that govern the granting of BS or BA degrees regardless of the disciplines offered. Georgetown University's School of Foreign Service awards the Bachelor of Science in Foreign Service (BSFS) degrees to all of its undergraduates, although many students major in humanities-oriented fields such as international history or culture and politics. University of Pennsylvania's Wharton School awards the BS in Economics to all of its undergraduates, regardless if the candidates major in economics or not. The London School of Economics offers BSc degrees in practically all subject areas, even those normally associated with the arts and humanities. Northwestern University's School of Communication grants the Bachelor of Science in Journalism degrees in all of its programs of study, including theater, dance, and radio/television/film. Meanwhile, the Oxbridge universities almost exclusively award the BA as a first degree. The decision to grant a BS or BA degree at some institutions also depends on the constituent colleges, even when the candidate pursues the same or similar subjects. For instance, Cornell University offers a BS degree in computer science from its College of Engineering and a BA degree in computer science from its College of Arts and Sciences. Likewise, for candidates majoring in computer science, Columbia University offers BS degrees for those enrolled in the School of Engineering and Applied Science but awards BA degrees for graduates of Columbia College. At Harvard University, the same undergraduate degree in computer science can be an A.B. if taken at Harvard College or Harvard John A. Paulson School of Engineering and Applied Sciences, and an A.L.B. at Harvard Extension School. === Argentina === In Argentina most university degrees are given as a license in a discipline. They are specific to a field and awarded to students upon completion of a course of study which lasts at least four and usually five years. In most cases, at the end of a course and as a mandatory condition for its completion (and ultimately, to obtain a degree), students are compelled to produce an original research project related to their field. This project is usually referred to as a thesis (although the term actually corresponds to post-graduate studies). === Australia, New Zealand and South Africa === In Australia, the BSc is generally a three to four-year degree. An honours year or a master's by research degree is required to progress on to the stage of Doctor of Philosophy (PhD). In New Zealand, in some cases, the honours degree comprises an additional postgraduate qualification. In other cases, students with strong performance in their second or third year, are invited to extend their degree to an additional year, with a focus on research, granting access to doctoral programs. In South Africa, the BSc is taken over three years, while the postgraduate BSc (Hons) entails an additional year of study. Admission to the honours degree is on the basis of a sufficiently high average in the BSc major; an honours degree is required for MSc level study, and admission to a doctorate is via the MSc. === Brazil === In Brazil, a Bachelor of Science degree is an undergraduate academic degree and is equivalent to a BSc (Hons). It could take from 4 to 6 years (8 to 12 periods) to complete, is also more specific and could be applied for Scientific Arts courses (like Engineering, Maths, Physics, etc.), somewhat is called Human Art courses in Brazil (like History, Portuguese and Literature and Lawyer studies for example) as well as for Health Arts (like Medicine, Nursery, Zootechnique, Veterinary and Biology for example). To be able to start the bachelor's degree in Brazil the candidate must prove to be proficient in different disciplines and have at least the accumulated Preliminary, Medium and High School degrees accomplished with the minimum merit of 60% to 70% of the degrees and a correspondent study period that can vary from 10 to 12 years minimum. The Bachelor of Science courses in Brazilian Universities normally have the first 1 to 2 years (first 2 to 4 periods) of basic fundamental disciplines (like for example Calculus I, II, III and IV for some engineering courses, Geometry basics and advanced, Analytical Laboratories experiments in Mechanics, Optics, Magnetism, etc.) and the last 2 to 3 years disciplines more related to the professional fields of that Bachelor of Science (for example Units Operations, Thermodynamics, Chemical Reactors, Industrial Processes, Kinetics for Chemical Engineering for example). Some disciplines are prerequisite to others and in some universities, the student is not allowed to course any discipline for the entire next period if he was unsuccessful in just one prerequisite discipline of the present period. Usually, the Bachelor of Science courses demand a one-year mandatory probation period by the end of the course (internship in the specific professional area, like a training period), followed by relatively elaborate written and oral evaluations. To get the certification as BSc, most universities require that the students achieve the accomplishment of 60% to 70% in all the "obligatory disciplines", plus the supervisioned and approved training period (like a supervisioned internship period), the final thesis of the course, and in some BSc programs, the final exam test. The final exam also is required so far. To be a professor, a Bachelor of Sciences is required to get a Licenciature degree, which lasts on top of the periods already studied until getting the BSc (Hons), plus 2 to 3 periods (1 to 1.5 years). With a master's degree (MSc) is also possible, which takes 3 to 5 periods more (1.5 to 2.5 years more). === Chile === In Chile, the completion of a university program leads to an academic degree as well as a professional title. The academic degree equivalent to Bachelor of Science is "Licenciado en Ciencias", which can be obtained as a result of completing a 4–6 year program. However, in most cases, 4-year programs will grant a Bachelor of Applied Science (Spanish: "Licenciatura en Ciencias Aplicadas") degree, while other 4-year programs will not grant to an academic degree. === Continental Europe === Many universities in Europe are changing their systems into the BA/MA system and in doing so also offering the full equivalent of a BSc or MSc (see Bologna Process). === Czech Republic === Universities in the Czech Republic are changing their systems into the Bachelor of Science/Master of Science system and in doing so also offering the full equivalent of a BSc (Bc.) or MSc (Mgr./Ing.). === Germany === In Germany, there are two kinds of universities: Universitäten and Fachhochschulen (which are also called University of Applied Sciences). Universitäten and Fachhochschulen – both also called Hochschulen - are legally equal, but Fachhochschulen have the reputation of being more related to practice and have no legal right to offer PhD programmes. The BSc in Germany is equivalent to the BSc(Hons) in the United Kingdom. Many universities in German-speaking countries are changing their systems to the BA/MA system and in doing so also offering the full equivalent of a BSc. In Germany the BA normally lasts between three and four years (six to eight semesters) and between 180 and 240 ECTS must be earned. === India === Bachelor of Science (B.Sc.) is usually a three-year graduate program in India offered by state and central universities. Some independent private colleges can also offer BS degrees with minimum changes in curriculum. B.Sc. is different from Bachelor of Engineering (B.E.) or Bachelor of Technology (B.Tech.). Two exceptions are the B.Sc. (Research) course offered by the Indian Institute of Science which lasts 4 years with an option to stay back an extra year for a master's thesis, the BS degrees in Physics, Data Science (Online degree), Electronic systems (Online degree), Medical Sciences & Engineering offered by IIT Madras which lasts four years and the BS-MS course offered by the IISERs which lasts for 5 years, all of which provide a more research oriented and interdisciplinary emphasis. From session 2022–23, the University of Delhi implemented NEP 2020 under which a bachelor's degree became a 4-year degree with multiple exit and entry options. A student receives a B.Sc. (research) field of study or B.Sc. (honours) field of multidisciplinary studies after the 4th year. === Ireland === Commonly in Ireland, graduands are admitted to the degree of Bachelor of Science after having completed a programme in one or more of the sciences. These programmes may take different lengths of time to complete. In Ireland, the former BS was changed to BSc (Hons), which is awarded after four years. The BSc (Ord) is awarded after three years. Formerly at the University of Oxford, the degree of BSc was a postgraduate degree; this former degree, still actively granted, has since been renamed MSc. === United Kingdom === Commonly in British Commonwealth countries, graduands are admitted to the degree of Bachelor of Science after having completed a programme in one or more of the sciences. These programmes may take different lengths of time to complete. A Bachelor of Science receives the designation BSc for an ordinary degree and BSc (Hons) for an honours degree. In England, Wales and Northern Ireland an honours degree is typically completed over a three-year period, though there are a few intensified two-year courses (with less vacation time). Bachelor's degrees (without honours) were typically completed in two years for most of the twentieth century. In Scotland, where access to university is possible after one less year of secondary education, degree courses have a foundation year making the total course length four years. === North America === In Canada, Mexico, and the United States, it is most often a four-year undergraduate degree, typically in engineering, computer science, mathematics, economics, finance, business, or the natural sciences. There are, however, some colleges and universities, notably in the province of Quebec, that offer three-year degree programs. == Typical completion period == === Three years === Algeria, Australia, Austria, Barbados, Belgium, Belize, Bosnia and Herzegovina (mostly three years, sometimes four), Cameroon, Canada (specifically Quebec), Côte d'Ivoire, Croatia (mostly three years, sometimes four), Czech Republic (mostly three years, sometimes four), Denmark, England (three or four years with a one-year placement in industry), Estonia, Finland, France, Germany (mostly three years, but can be up to four years), Hungary, Iceland, India (three-year BSc in arts and pure sciences excluding engineering, Agriculture and medicine, four years BS, Bsc (hons.) Agriculture, Engineering, four years for engineering program "Bachelor of Engineering", four years for Agriculture program "Bachelor of Agriculture" and five years for medicine program "Bachelor of Medicine and Bachelor of Surgery"), Ireland (Ordinary), Israel (for most subjects), Italy, Jamaica (three or four years), Latvia (three or four years), Lebanon (three or four years, five years for Bachelor of Engineering), Malaysia, New Zealand, the Netherlands (three years for research universities, four years for universities of applied sciences), Northern Ireland, Norway, Poland, Portugal, Romania, Scotland (Ordinary), Singapore (honours degree takes 4 years), Slovakia, Slovenia, South Africa (honours degree takes 4 years), Sweden, Switzerland, Trinidad and Tobago, Uganda (mostly three years, sometimes four), United Arab Emirates, Wales, and Zimbabwe. === Four years === Afghanistan, Albania (four or five years), Armenia (four or five years), Australia (honours degree), Azerbaijan (four or five years), Bahrain, Bangladesh (four or five years), Belarus, Belize, Bosnia and Herzegovina, Brazil (four or five years), Brunei (three or four years), Bulgaria, Canada (except Quebec, four or five years), China, Cyprus, the Dominican Republic, Egypt (four or five years), Ethiopia (engineering, five years), Finland (engineering, practice in industry not included), Georgia, Ghana (three or four years), Greece (four or five years), Guatemala, Haiti (three or four years), Hong Kong (starting from 2012; three years prior to then), India (Some universities and institutes offer 4 year degrees ), Indonesia (four or five years), Iran (four or five years), Iraq, Ireland (Honours Degree), Israel (engineering degree), Japan, Jordan (four to five years), Kazakhstan, Kenya, Kuwait, Libya, Lithuania, North Macedonia (three, four or five years), Malawi (four or five years), Malta, Mexico, Montenegro (three or four years), Myanmar, Nepal (previously three, now four years), the Netherlands (three years for research universities, four years for universities of applied sciences), New Zealand (honours degree), Nigeria (four or five years), Pakistan (four or five years), the Philippines (four or five years), Romania, Russia, Saudi Arabia, Scotland (Honours Degree), Serbia (three or four years), Spain, South Africa (fourth year is elective — to obtain an Honours degree, which is normally a requirement for selection into a master's degree program), South Korea, Sri Lanka (three, four, or five (specialized) years), Taiwan, Tajikistan (four or five years), Thailand, Turkmenistan (four years), Tunisia (only a Bachelor of Science in Business Administration is available, solely awarded by Tunis Business School), Turkey, Ukraine, the United States, Uruguay (four, five, six, or seven years), Vietnam (four or five years), Yemen, and Zambia (four or five years). === Five years === Canada (except Quebec, four or five years), Cuba (five years), Greece (four or five years), Peru, Argentina, Colombia (five years), Brazil (four or five years), Mexico (four or five years), Chile (five or six years), Venezuela (five years), Egypt (four or five years), Haiti (four or five years), Iran (four or five years), the Philippines (four or five years). Bangladesh (four or five years), Pakistan (four or five years), Indonesia (four or five years), Nigeria (four or five years), six months dedicated to SIWES (Students Industrial Work Exchange Scheme) but for most sciences and all engineering courses only. A semester for project work/thesis not excluding course work during the bachelor thesis. Excluding one year for the compulsory National Youth Service Corps (NYSC), para-military and civil service. North Macedonia, Sierra Leone (four years dedicated to coursework), Slovenia (four or five years), Sudan (five years for BSc honours degree and four years for BSc ordinary degree), and Syria. In Algeria, the student presents a thesis in front of a Jury at the end of the fifth year. Some universities in Canada (such as University of British Columbia and Vancouver Island University) have most of their science and applied science students extend their degree by a year compared to other institutions. === Six years === In Chile, some undergraduate majors such as engineering and geology are designed as six-year programs. However, in practice it is not uncommon for students to complete such programs over the course of ten years, while studying full-time without leaves of absence. This is in part due to a strict grading system where the highest grade of a typical class can be as low as 60% (C-). There are studies that suggest a direct correlation between reduced social mobility and differences unique to the Chilean higher education system. == See also == British undergraduate degree classification British degree abbreviations List of tagged degrees Master of Science == Notes == == References ==
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https://en.wikipedia.org/wiki/Bachelor_of_Science
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The Gay Science (German: Die fröhliche Wissenschaft; sometimes translated as The Joyful Wisdom or The Joyous Science) is a book by Friedrich Nietzsche published in 1882, and followed by a second edition in 1887 after the completion of Thus Spoke Zarathustra and Beyond Good and Evil. This substantial expansion includes the addition of a fifth book to the existing four books of The Gay Science, as well as an appendix of songs. It was described by Nietzsche as "the most personal of all my books", and contains more poems than any of his other works. == Title == The book's title, in the original German and in translation, uses a phrase that was well known at the time in many European cultures and had specific meaning. One of its earliest literary uses is in Rabelais's Gargantua and Pantagruel ("gai sçavoir"). It was derived from a Provençal expression (gai saber) for the technical skill required for poetry-writing. Johann Gottfried Herder elaborated on this in letters 85, 90, and 102 (1796) of his Letters for the Advancement of Humanity. The expression proved durable and was used as late as 19th-century American English by Ralph Waldo Emerson and E. S. Dallas. It was also used in deliberately inverted form, by Thomas Carlyle in "the dismal science", to criticize the emerging discipline of economics by comparison with poetry. The book's title was first translated into English as The Joyful Wisdom, but The Gay Science has become the common translation since Walter Kaufmann's version in the 1960s. Kaufmann cites The Shorter Oxford English Dictionary (1955) that lists "The gay science (Provençal gai saber): the art of poetry." In Ecce Homo, Nietzsche refers to the poems in the Appendix of The Gay Science, saying they were ... written for the most part in Sicily, are quite emphatically reminiscent of the Provençal concept of gaia scienza—that unity of singer, knight, and free spirit which distinguishes the wonderful early culture of the Provençals from all equivocal cultures. The very last poem above all, "To the Mistral", an exuberant dancing song in which, if I may say so, one dances right over morality, is a perfect Provençalism. This alludes to the birth of modern European poetry that occurred in Provence around the 11th century, whereupon, after the culture of the troubadours fell into almost complete desolation and destruction due to the Albigensian Crusade (1209–1229), other poets in the 14th century ameliorated and thus cultivated the gai saber or gaia scienza. In a similar vein, in Beyond Good and Evil Nietzsche observed that, ... love as passion—which is our European speciality—[was invented by] the Provençal knight-poets, those magnificent and inventive human beings of the "gai saber" to whom Europe owes so many things and almost owes itself. The original English translation as Joyful Wisdom is more comprehensible to the modern reader given the contrasting modern English meanings of "gay" and "science". The German fröhlich can be translated "happy" or "joyful", cognate to the original meanings of "gay" in English and other languages. However Wissenschaft is not "wisdom" (wisdom = Weisheit), but a propensity toward any rigorous practice of a poised, controlled, and disciplined quest for knowledge. The common English translation "science" is misleading if it suggests natural sciences—clearly inappropriate in this case, where "scholarship" is preferable, implying humanities. == Content == The book is usually placed within Nietzsche's middle period, during which his work extolled the merits of science, skepticism, and intellectual discipline as routes to mental freedom. In The Gay Science, Nietzsche experiments with the notion of power but does not advance any systematic theory. === Amor fati === The affirmation of the Provençal tradition (invoked through the book's title) is also one of a joyful "yea-saying" to life. Nietzsche's love of fate naturally leads him to confront the reality of suffering in a radical way. For to love that which is necessary demands not only that we love the bad along with the good, but that we view the two as inextricably linked. In section 3 of the preface, he writes:Only great pain is the ultimate liberator of the spirit... I doubt that such pain makes us 'better'; but I know that it makes us more profound.This is representative of amor fati, the general outlook on life that he articulates in section 276:I want to learn more and more to see as beautiful what is necessary in things; then I shall be one of those who makes things beautiful. Amor fati: let that be my love henceforth! I do not want to wage war against what is ugly. I do not want to accuse; I do not even want to accuse those who accuse. Looking away shall be my only negation. And all in all and on the whole: some day I wish to be only a Yes-sayer. === Eternal recurrence === The book contains Nietzsche's first consideration of the idea of the eternal recurrence, a concept which would become critical in his next work Thus Spoke Zarathustra and underpins much of the later works. What if some day or night a demon were to steal after you into your loneliest loneliness and say to you: 'This life as you now live it and have lived it, you will have to live once more and innumerable times more' ... Would you not throw yourself down and gnash your teeth and curse the demon who spoke thus? Or have you once experienced a tremendous moment when you would have answered him: 'You are a god and never have I heard anything more divine.' === "God is dead" === The book mentions an occurrence of the famous formulation "God is dead"; this can be found in later works such as Thus Spoke Zarathustra. Section 125 depicts The Parable of the Madman who is searching for God. He accuses us all of being the murderers of God. "'Where is God?' he cried; 'I will tell you. We have killed him—you and I. All of us are his murderers..." == Notes == == References == Kaufmann, Walter, Nietzsche: Philosopher, Psychologist, Antichrist, Princeton University Press, 1974. The Gay Science: With a Prelude in Rhymes and an Appendix of Songs by Friedrich Nietzsche; translated, with commentary, by Walter Kaufmann. Vintage Books, 1974, ISBN 0-394-71985-9 Pérez, Rolando. Towards a Genealogy of the Gay Science: From Toulouse and Barcelona to Nietzsche and Beyond. eHumanista/IVITRA. Volume 5, 2014. == External links == Die fröhliche Wissenschaft at Nietzsche Source Oscar Levy's 1924 English edition, trans. Thomas Common at the Internet Archive [1] The Parable of the Madman (Friedrich Nietzsche, The Gay Science (1882, 1887) para. 125; Walter Kaufmann ed. (New York: Vintage, 1974), pp. 181–182.) The Gay Science public domain audiobook at LibriVox
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https://en.wikipedia.org/wiki/The_Gay_Science
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"On Exactitude in Science", or "On Rigor in Science" (Spanish: "Del rigor en la ciencia") is a one-paragraph short story by Argentine writer Jorge Luis Borges. == Plot == The story, credited fictionally as a quotation from "Suárez Miranda, Viajes de varones prudentes, Libro IV, Cap. XLV, Lérida, 1658", describes an empire where cartography becomes so exact that only a map on the same scale as the empire itself will suffice. Later generations come to disregard the map, however, and as it decays, so does the land and society beneath it. == Publication history == The story was first published in the March 1946 edition of Los Anales de Buenos Aires as part of a piece called "Museo" credited to "B. Lynch Davis", a joint pseudonym of Borges and Adolfo Bioy Casares. It was collected later that year in the 1946 second Argentinian edition of Borges' Historia universal de la infamia (A Universal History of Infamy). The story is no longer included in current Spanish editions of the Historia universal de la infamia, as since 1961 it has appeared as part of Borges' collection El hacedor. The names "B. Lynch Davis" and "Suárez Miranda" would be combined later in 1946 to form another pseudonym, B. Suárez Lynch, under which Borges and Bioy Casares published Un modelo para la muerte, a collection of detective fiction. == Influences and legacy == "On Exactitude in Science" elaborates on a concept in Lewis Carroll's Sylvie and Bruno Concluded: a fictional map that had "the scale of a mile to the mile." One of Carroll's characters notes some practical difficulties with this map and states that "we now use the country itself, as its own map, and I assure you it does nearly as well." Italian writer Umberto Eco expanded upon the theme, quoting the story as the epigraph for his short story "On the Impossibility of Drawing a Map of the Empire on a Scale of 1 to 1", collected in his How to Travel with a Salmon and Other Essays. French philosopher Jean Baudrillard cited "On Exactitude in Science" as a predecessor to his concept of hyperreality in his 1981 treatise Simulacra and Simulation. == See also == Map–territory relation Welcome to the Desert of the Real == References == == External links == Full text, translated to English by Andrew Hurley Spanish Audio "On Rigor in Science", read by J. L. Borges
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The following scientific events occurred, or are scheduled to occur in 2025. The United Nations declared 2025 the International year of quantum science and technology. == Events == === January === 1 January – Detailed telemetry data from the Parker Solar Probe is received, following its passage through the Sun's corona. 2 January The biggest dinosaur fossil trackway ever found in the UK is reported at a quarry in Oxfordshire, consisting of 200 huge footprints made during the mid-Jurassic. Bioengineers at Rice University report having developed a novel "construction kit" for building custom sense-and-respond circuits in human cells. 3 January – Researchers report discovering a new class of anti-malaria antibodies. 8 January – Scientists publish a comprehensive map of protein locations within human cells, offering potential new insights into how cells respond to infections and other changing circumstances. 9 January – The El Capitan supercomputer is officially dedicated at the Lawrence Livermore National Laboratory in Livermore, United States. 10 January The European Copernicus Climate Change Service reports that 2024 was the world's hottest year on record, and the first calendar year to pass the symbolic threshold of 1.5°C of global warming. The first fully 3D printed microscope is revealed by the University of Strathclyde, made in just a few hours and for a fraction of the cost of traditional devices. 13 January – Researchers discover what could be the world's oldest three-dimensional map in a cave in the Paris Basin of France, dating back 13,000 years. 15 January – The European Space Agency's Gaia spacecraft ends its operation after 11 years of mapping the Milky Way galaxy, during which time it made three trillion observations of two billion stars. 16 January Microsoft researchers publish details of MatterGen, a generative AI tool for materials design. The first two-dimensional (2D) mechanically interlocked material is demonstrated by Northwestern University, consisting of 100 trillion bonds per square centimetre, which its creators describe as having exceptional flexibility and strength. Adding just 2.5% of the new material to Ultem boosted the latter's tensile modulus by 45%. The air monitoring station at Mauna Loa Observatory in Hawaii reports that CO2 jumped by 3.58 parts per million (ppm) in 2024, exceeding the previous record of 3.36 ppm set in 2023. The global atmospheric concentration of CO2 is now at 427 ppm, more than 50% higher than the pre-industrial level. 21 January Coral bleaching on the southern Great Barrier Reef in early 2024 is reported to have struck 80% of colonies, with some coral genera, such as Acropora, experiencing a 95% mortality rate. More than a third (34%) of the Arctic-boreal zone is now reported to be a source of carbon emissions, rather than a carbon sink, a figure that rises to 40% when including emissions from fires. The exoplanet WASP-127b is discovered to have wind speeds of up to 33,000 km/h, the fastest jetstream of its kind ever measured. 22 January – The second Trump administration imposes an immediate freeze on scientific grants, communications, hiring, and meetings at the National Institutes of Health (NIH) – by far the biggest supporter of biomedical research worldwide – impacting $47.4 billion worth of activities. 23 January Machine learning and 3D printing are used at the University of Toronto to design nano-architected materials exhibiting the strength of carbon steel but the lightness of Styrofoam. A study of adults with attention deficit hyperactivity disorder (ADHD) finds that the condition may reduce life expectancy by 4.5 to 9 years for men, and 6.5 to 11 years for women. 24 January – A study by the University of Birmingham finds that electric vehicles now have an average lifespan of 18.4 years, outlasting the average diesel vehicle at 16.8 years and almost matching the average petrol vehicle at 18.7 years. 29 January – The European Space Agency (ESA) announces that it has begun monitoring the asteroid 2024 YR4, which at the time had a 1 in 77 (1.3%) chance of impacting Earth on 22 December 2032. === February === 3 February – Researchers in Berkeley and Cambridge attach copper nanoflower catalysts on perovskite-based artificial leaves for solar-driven hydrocarbon synthesis. Devices can produce ethane and ethylene at high rates by coupling CO2 reduction with glycerol oxidation into value-added chemicals. 7 February – Researchers develop an AI chip, smaller than a grain of salt, that mounts on the tip of an optical fibre and uses a "diffractive neural network" to decode images at light speed with very low energy. This breakthrough promises advances in efficient medical imaging and quantum communication technologies. 10 February The microlensing event MOA-2011-BLG-262L is confirmed to be associated with the highest-velocity exoplanet system detected to date, moving at 541 km/s (1.2 million mph), which is close to the escape velocity for the Milky Way galaxy. Following an increase in the impact probability of 2024 YR4 – from 1.3% to 2.1% – the European Space Agency announces that it will use the advanced capabilities of the James Webb Space Telescope to observe the asteroid, in order to better determine its size and trajectory. 12 February The WEST tokamak in France is reported to have maintained plasma for 1,337 seconds, a new world record duration for nuclear fusion and 25% longer than a similar effort by China the previous month. A new blood test able to detect early-stage pancreatic cancer with 85% accuracy is developed by Oregon Health & Science University. 13 February – Scientists at the University of Cambridge report the creation of a solar-powered reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel. 15 February – A new record-low global sea ice extent is reported, dipping below the previous lowest that occurred in early 2023. 18 February The impact probability of 2024 YR4 is raised by NASA, from 2.1% to 2.6% and then 3.1% in the same day. The first 3D mapping of an exoplanet atmosphere is achieved by the European Southern Observatory's Very Large Telescope. WASP-121b (also known as Tylos) is found to have powerful winds carrying elements like iron and titanium, creating intricate weather patterns across its atmosphere. 24 February – NASA formally announces that asteroid 2024 YR4 now poses "no significant threat" to Earth in 2032 and beyond, as the chances of an impact drops to 1-in-59,000 (0.0017%). This means a planetary defense mission to intercept and deflect the object in 2028 during a close flyby of Earth will not be necessary. 27 February OpenAI announces a research preview of GPT-4.5, its largest and most advanced AI model to date. Researchers at AWS and Caltech develop the Ocelot chip, using "cat qubits" to reduce quantum computing errors by up to 90%, making error correction more efficient and scalable. 28 February – An electronic device called "e-Taste", developed by Ohio State University, is shown to replicate the perception of taste, which could enhance virtual reality experiences. === March === 2 March – Firefly Aerospace successfully lands the Blue Ghost Mission 1 on the Moon as part of NASA's Commercial Lunar Payload Services program, delivering payloads to Mare Crisium with instruments to study lunar regoliths and the interactions between solar wind and Earth's magnetic field. 4 March – De-extinction company Colossal Biosciences announces the creation of a "woolly mouse" with eight modified genes, expressing mammoth-like traits relevant to cold adaptation and providing a platform for validation of genome engineering targets. 5 March – Italian researchers report turning light into a supersolid for the first time. 6 March – A study in Science finds that butterfly populations in the U.S. declined by 22% between 2000 and 2020, with 13 times as many species decreasing as increasing, raising concerns about future biodiversity loss. 10 March – A study in the journal PNAS finds that microplastic pollution reduces photosynthesis in plants and algae by up to 12%, leading to estimated annual food losses of 110–361 million tonnes of crops and up to 24 million tonnes of seafood. Without action to reduce plastic waste, this could lead to another 400 million people at risk of starvation within two decades. 11 March The discovery of 128 new moons of Saturn is reported, by astronomers using the Canada–France–Hawaii Telescope, bringing the gas giant's total number of confirmed satellites to 274. Three new rocky exoplanets, all smaller than Earth in size, are detected around Barnard's Star, the closest solitary star to our own Sun at just 5.96 light-years away. Barnard b, a candidate world that observations had hinted at previously, is also confirmed, bringing the total number of known planets around the star to four. 13 March – The first image of two PINK1 proteins attached to the membrane of a mitochondrion is obtained, via cryo-electron microscopy, a potential breakthrough in developing treatments for Parkinson's disease. 20 March – Oxygen is discovered in JADES-GS-z14-0, the most distant known galaxy, located 13.4 billion light-years from Earth. 26 March Aurorae are confirmed on Neptune for the first time, seen by combining visible light images from the Hubble Space Telescope with near-infrared images from the James Webb Space Telescope. A study in The Lancet finds that cuts to foreign aid proposed by major donor countries, such as the US and UK, could undo decades of progress made to end HIV/AIDS as a public health threat, with potentially 10.8m additional new infections by 2030. 31 March – GPT-4.5 is reported to have passed the Turing Test. === April === 1 April – Fram2 launches aboard a SpaceX Falcon 9 rocket, becoming the first crewed spaceflight to enter a polar retrograde orbit, i.e., to fly over Earth's poles. 2 April – The world's smallest pacemaker – able to fit inside the tip of a syringe and be non-invasively injected into the body – is demonstrated by scientists at Northwestern University. The device, measuring just 3.5 millimeters in length, is designed for temporary use and can be made to biodegrade within a set number of days, depending on a patient's needs. 7 April – Colossal Biosciences announces Romulus, Remus, and Khaleesi, genetically modified grey wolves which reproduced characteristics of extinct dire wolves. 8 April – Maxwell Labs, in collaboration with Sandia National Laboratories and the University of New Mexico, announces a laser-based photonic cooling system for computer chips, aiming to reduce data centre cooling energy use by up to 40% while improving processor performance. 16 April Scientists report a new method of generating electricity from falling rainwater using plug flow in vertical tubes, converting over 10% of the water's energy into electricity and producing enough power to light 12 LEDs. OpenAI announces the launch of two new AI models, o3 and o4-mini. 17 April – The atmosphere of K2-18b, a candidate water world located 124 light-years away, is found to contain large quantities of dimethyl sulfide and dimethyl disulfide – two compounds that, on Earth, are only known to be produced by life. This discovery, while requiring further proof, is described as "the strongest evidence to date for a biological activity beyond the Solar System". 20 April – NASA's Lucy spacecraft returns images of the main belt asteroid Donaldjohanson, revealing it to be a contact binary and larger than originally estimated. 22 April – Astronomers at MIT report the discovery of BD+05 4868Ab, a small rocky exoplanet located 142 light-years from Earth, which is rapidly disintegrating due to extreme heat from its nearby host star. The planet, orbiting every 30.5 hours, exhibits a comet-like tail of vaporised minerals extending up to 9 million kilometres. It is estimated to be losing mass equivalent to Mount Everest each orbit and may completely evaporate within 1–2 million years. 27 April – Astronomers report the discovery of the Eos cloud, a vast molecular hydrogen cloud located about 300 light-years from Earth, revealed through far-ultraviolet emission techniques. Expected to evaporate within 6 million years, Eos is among the largest and closest molecular clouds ever found. 30 April Engineers at ITER complete the construction of the world's largest and most powerful pulsed superconducting electromagnet system, marking a major milestone on the path to sustained nuclear fusion. The Central Solenoid and surrounding magnets will confine plasma at 150 million °C, enabling ITER to produce 500 megawatts of fusion power from just 50 megawatts of input. The Minor Planet Center announces two additional moons of Jupiter, bringing the planet's total moon count to 97. === May === 8 May The ALICE experiment at CERN detects the conversion of lead into gold. A study by Uppsala University in Sweden finds that lack of sleep can increase the risk of cardiovascular disease. Researchers found that just three nights of restricted sleep – around four hours a night – triggered changes in the blood linked to a higher risk of heart disease. 9 May – Kosmos 482, an attempted Soviet Venus probe which failed to escape low Earth orbit, crashes back to Earth after more than 53 years. 13 May – Genes linked to obsessive–compulsive disorder (OCD) are discovered for the first time. A study involving more than 2 million people identifies 250 genes linked to the condition. 20 May The 150th anniversary of the signing of the Metre Convention, which established the BIPM, one of the first international organizations, is celebrated. Google DeepMind announces Veo 3, a new state-of-the-art video generation model. The company also boosts the performance of Gemini 2.5 Pro, its flagship AI model. MIT releases a detailed report on the energy footprint of generative AI. Some models are shown to require the equivalent of running a microwave oven for an hour to produce five seconds of video. 21 May The world's first gonorrhoea vaccine is launched by NHS England, with an efficacy of 30–40%. The discovery of 2017 OF201, a new dwarf planet candidate in the outer Solar System, is reported. 22 May – A review by Murdoch University in Australia finds that agricultural soils now hold around 23 times more microplastics than the oceans. == Predicted and scheduled events == 22 June – The Royal Observatory Greenwich will celebrate its 350th anniversary. September – NASA will launch its Pandora Mission, which aims to observe 20 stars and their 39 exoplanets. === Date unknown === NASA's IMAP probe will launch toward Lagrange point 1 to collect interstellar dust and investigate space weather. The Vera C. Rubin Observatory is expected to begin science operations in late 2025. Science-related budgets US: Various details about planned science-related spending for 2025 have been described with some information on the planned research subjects or areas. == See also == Category:Science events Category:Science timelines List of emerging technologies List of years in science == References == == External links == Media related to 2025 in science at Wikimedia Commons
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Generative science is an area of research that explores the natural world and its complex behaviours. It explores ways "to generate apparently unanticipated and infinite behaviour based on deterministic and finite rules and parameters reproducing or resembling the behavior of natural and social phenomena". By modelling such interactions, it can suggest that properties exist in the system that had not been noticed in the real world situation. An example field of study is how unintended consequences arise in social processes. Generative sciences often explore natural phenomena at several levels of organization. Self-organizing natural systems are a central subject, studied both theoretically and by simulation experiments. The study of complex systems in general has been grouped under the heading of "general systems theory", particularly by Ludwig von Bertalanffy, Anatol Rapoport, Ralph Gerard, and Kenneth Boulding. == Scientific and philosophical origins == The development of computers and automata theory laid a technical foundation for the growth of the generative sciences. For example: Cellular automata are mathematical representations of simple entities interacting under deterministic rules to manifest complex behaviours. They can be used to model emergent processes of the physical universe, neural cognitive processes and social behavior. Conway's Game of Life is a zero-player game based on cellular automata, meaning that the only input is in setting the initial conditions, and the game is to see how the system evolves. In 1996 Joshua M. Epstein and Robert Axtell wrote the book Growing Artificial Societies which proposes a set of automaton rules and a system called Sugarscape which models a population dependent on resources (called sugar). Artificial neural networks attempt to solve problems in the same way that the human brain would, although they are still several orders of magnitude less complex than the human brain and closer to the computing power of a worm. Advances in the understanding of the human brain often stimulate new patterns in neural networks. One of the most influential advances in the generative sciences as related to cognitive science came from Noam Chomsky's (1957) development of generative grammar, which separated language generation from semantic content, and thereby revealed important questions about human language. It was also in the early 1950s that psychologists at the MIT including Kurt Lewin, Jacob Levy Moreno and Fritz Heider laid the foundations for group dynamics research which later developed into social network analysis. == See also == Generative systems – Technologies that can produce change driven by audiences == References == == External links == http://www.swarthmore.edu/socsci/tburke1/artsoc.html Archived 2005-04-09 at the Wayback Machine (Artificial Societies, Virtual Worlds and the Shared Problems and Possibilities of Emergence) http://jasss.soc.surrey.ac.uk/JASSS.html (The Journal of Artificial Societies and Social Simulation)
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https://en.wikipedia.org/wiki/Generative_science
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Science of science policy (SoSP) is an emerging interdisciplinary research area that seeks to develop theoretical and empirical models of the scientific enterprise. This scientific basis can be used to help government, and society in general, make better R&D management decisions by establishing a scientifically rigorous, quantitative basis from which policy makers and researchers may assess the impacts of the nation's scientific and engineering enterprise, improve their understanding of its dynamics, and assess the likely outcomes. Examples of research in the science of science policy include models to understand the production of science, qualitative, quantitative and computational methods to estimate the impact of science, and processes for choosing from alternative science portfolios.: 5 == Federal SoSP effort == The federal government of the United States has long been a supporter of SoSP. In 2006, in response to Office of Science and Technology Policy Director John H. Marburger's challenge for a new "science of science policy," the National Science and Technology Council's Subcommittee on Social, Behavioral and Economic Sciences (SBE) established an Interagency Task Group on Science of Science Policy (ITG) to serve as part of the internal deliberative process of the Subcommittee. In 2008, the SoSP ITG developed and published The Science of Science Policy: A Federal Research Roadmap, which outlined the Federal efforts necessary for the long-term development of a science of science policy, and presented this Roadmap to the SoSP Community. The ITG's subsequent work has been guided by the questions outlined in the Roadmap and the action steps developed at the workshop. Furthermore, since 2007, the National Science Foundation, in support of academic research to advance the field, has awarded grants from the Science of Science and Innovation Policy (SciSIP) program. The SciSIP research supports and complements the Federal SoSP efforts by providing new tools with immediate relevance to policymakers. == Science of Science and Innovation Policy program == The Science of Science and Innovation Policy (SciSIP) program was established at the National Science Foundation in 2005 in response to a call from John Marburger for a "specialist scholarly community" to study the science of science policy. The program has three major goals: advancing evidence-based science and innovation policy decision making; building a scientific community to study science and innovation policy; and leveraging the experience of other countries. Between 2007 and 2011, over one hundred and thirty awards were made in five rounds of funding. The awardees include economists, sociologists, political scientists, and psychologists. Some of these awards are already showing results in the form of papers, presentations, software, and data development. == See also == Metascience Evidence-based policy Evidence-based practices == References == == Further reading ==
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Science in science fiction is the study or of how science is portrayed in works of science fiction, including novels, stories, and films. It covers a large range of topics. Hard science fiction is based on engineering or the "hard" sciences (for example, physics, astronomy, or chemistry). Soft science fiction is based on the "soft" sciences, and especially the social sciences (anthropology, sociology, psychology, of political science). The accuracy of the science portrayed spans a wide range - sometimes it is an extrapolation of existing technology, sometimes it is a realistic or plausible portrayal of a technology that does not exist, but which is plausible from a scientific perspective; and sometimes it is simply a plot device that looks scientific, but has no basis in science. Examples are: Realistic case: In 1944, the science fiction story Deadline by Cleve Cartmill depicted the atomic bomb. This technology was real, unknown to the author. Extrapolation: Arthur C. Clarke wrote about space elevators, basically a long cable extending from the Earth's surface to geosynchronous orbit. While we cannot build one today, it violates no physical principles. Plot device: The classic example of an unsupported plot device is faster-than-light drive, often called a "warp drive". It is unsupported by physics as we know it, but needed for galaxy-wide plots with human lifespans. Criticism and commentary on how science is portrayed in science fiction is done by academics from science, literature, film studies, and other disciplines; by literary critics and film critics; and by science fiction writers and sci fi fans and bloggers. == Hard science in science fiction == Planets in science fiction Time travel in science fiction Weapons in science fiction Materials science in science fiction Genetics in fiction == Social science in science fiction == Sex and sexuality in speculative fiction Women in science fiction Gender in speculative fiction Reproduction and pregnancy in speculative fiction == See also == Category Fiction about physics Physics and Star Wars == References == == Bibliography == The Science in Science Fiction by Brian Stableford, David Langford, & Peter Nicholls (1982) Science Fiction with Good Astronomy & Physics
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Game Science (Chinese: 游戏科学; pinyin: Yóuxì Kēxué) is a Chinese video game development and publishing company founded by Feng Ji and Yang Qi in 2014. The studio is headquartered in Shenzhen and has an additional office in Hangzhou. It is best known for developing the video game Black Myth: Wukong (2024). == History == === Formation and early period (2014–2017) === Game Science was founded on 13 June 2014. The seven founding members were former employees of Tencent and worked as developers for the massively multiplayer online game Asura at the company. At the time of their studio's formation, China's mobile games market was rapidly expanding, so they made the decision to develop mobile games in order to survive as a studio. In collaboration with publisher NetEase, Game Science developed 100 Heroes, a mobile game inspired by the Romance of the Three Kingdoms. The game attracted 500 thousand players in the first month and nearly 800 thousand players in its first year. Yang Qi proposed a single-player game as their next project, but the idea was shelved due to the high costs and risks involved for a newly established studio. Instead, their next project became the mobile game Art of War: Red Tides. In 2019, the game was acquired by Chaoxi Guangnian, a game company under ByteDance. Lilith Games CEO Wang Xiwen—a former colleague of Feng Ji at Tencent—introduced Feng Ji and Hero Games CEO Daniel Wu to each other, which ultimately led to Wu investing in Game Science. During a meeting in their early days, Game Science committed to pursuing a vision of creating games that move and resonate with them personally. During a speech at an art exhibition in April 2025, Feng Ji remarked that this was a core value of the studio. He explained that the idea is that a project can progress effectively if game developers, as users themselves, have a better understanding of both the work and its players, but that they only represent themselves and thus must constantly experiment to find the intersection between themselves and players. The studio's vision also retained the ideas reflected in Feng Ji's 2007 article "Who Murdered Our Games?" (谁谋杀了我们的游戏), which offers a critique from the perspective of a game planner, arguing that many games fail before they even leave the development stage, these failures occur when development teams lack excitement for the games they are creating, the industry has fostered a mentality where players are treated like livestock in the pursuit for engagement and profit, and the industry has a dark side characterized by capital-driven practices that alienate players and degrade their experiences. In a 2024 interview with China Central Television, Feng Ji discussed this perspective, explaining that game developers such as himself and his colleagues should focus on gameplay and storytelling to captivate players but must remain cautious not to fall into capital-driven practices, emphasizing that a reasonable question to ask yourself—his standard for their products—is whether you would recommend your children, friends, and relatives to play your games with confidence. === Black Myth: Wukong (2018–present) === After the mobile games 100 Heroes and Art of War: Red Tides, Game Science started the development of Black Myth: Wukong in 2018. The decision to develop an AAA game, according to operations director Lan Weiyi, came after the realization that there were more Steam users from China than the United States. Before the development on the game began, Game Science conducted a company-wide survey that revealed that action role-playing games were the games with the longest playtimes on Steam among the staff, which led to a focus on action role-playing games for both the studio and the Black Myth project. Feng Ji said that this approach would allow them to better understand and empathize with players, because they themselves would be players of the types of games they were creating. Game Science decided to have a team focused on mobile games and a team focused on single-player games. Considering the differences in development cycles between these two kinds of games, Feng Ji and Yang Ji sought to find a new environment appropriate for a team working on single-player games. Ultimately, the Black Myth development team moved from Shenzhen to Hangzhou due to its "slower pace and lower living costs". In August 2020, Game Science released the first trailer of Black Myth: Wukong as a way to recruit more talent for the company. At the time, the game's development team had 30 members. Due to the trailer going viral, Game Science received over 10,000 resumes. Some were from AAA gaming companies with candidates even from outside of China who were willing to apply for a Chinese working visa at their own cost. A day after the trailer's release, there were people showing up at the door of the company asking for a job. The development team expanded to 140 employees according to the game's credit list. The South China Morning Post reports that Hero Games acquired a 19% stake in Game Science through its wholly-owned subsidiary Tianjin Hero Financial Holding Technology in 2017, but sold the stake in 2022 with payment partly outstanding. When asked about their ownership and relationship by VentureBeat, Hero Games chairman Dino Ying said that he could not comment on that. As reported in March 2021, Tencent obtained a total stake of 5% in Game Science. They aimed to help their former employees on some projects, but committed to not interfering with the operation and decision-making of Game Science. In 2023, IGN released a report that alleged a history of sexism within the company, citing as evidence screenshots of personal posts by company figures in Chinese social media and suggestive hiring posters from 2015. Chinese outlets HK01, an online news portal, and GameLook, a game-industry research website, criticized IGN's report, arguing that the article uses examples taken out of context and vulgar but not sexist. HK01 and Gamebase reported that the relevant posts had been mistranslated. HK01 also reported that the anonymous criticism quoted by the article cannot be verified. Game Science declined to address questions about the allegations. On social media, Khee Hoon Chan, a co-author of the IGN article, called for online piracy and made explicit comments toward Game Science. Hero Games' Dino Ying commented that Game Science tries not to get into distractions. Black Myth: Wukong was released in August 2024 and sold 20 million units in its first month, making it one of the fastest-selling games of all time. In 2024, Game Science and the electric automobile maker BYD Company established a strategic partnership to digitize China's national treasures and landmarks to contribute to their protection and provide a scientific basis for future restoration work. This involves 3D scanning in multiple provinces, starting in Shanxi which was heavily featured in Black Myth: Wukong, across all of China. == Games and products == Game Science have made several video games. In January 2025, Game Science published a Chinese New Year short film unveiling their official merchandise brand BLACK MYTH. The brand initially focuses on Black Myth: Wukong and aims to include other content in the long term. A dedicated team, separate from the game developers, was formed to handle the design, production, and operation of the brand. == References == == External links == Official website
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A radio science subsystem (RSS) is a subsystem placed on board a spacecraft for radio science purposes. == Function of the RSS == The RSS uses radio signals to probe a medium such as a planetary atmosphere. The spacecraft transmits a highly stable signal to ground stations, receives such a signal from ground stations, or both. Since the transmitted signal parameters are accurately known to the receiver, any changes to these parameters are attributable to the propagation medium or to the relative motion of the spacecraft and ground station. The RSS is usually not a separate instrument; its functions are usually "piggybacked" on the existing telecommunications subsystem. More advanced systems use multiple antennas with orthogonal polarizations. == Applications == Radio science is commonly used to determine the gravity field of a moon or planet by observing Doppler shift. This requires a highly stable oscillator on the spacecraft, or more commonly a "2-way coherent" transponder that phase locks the transmitted signal frequency to a rational multiple of a received uplink signal that usually also carries spacecraft commands. Another common radio science observation is in radio occultation, performed as a spacecraft is occulted by a planetary body. As the spacecraft moves behind the planet, its radio signals cuts through successively deeper layers of the planetary atmosphere. Measurements of signal strength and polarization vs time can yield data on the composition and temperature of the atmosphere at different altitudes. It is also common to use multiple radio frequencies coherently derived from a common source to measure the dispersion of the propagation medium. This is especially useful in determining the free electron content of a planetary ionosphere. == Spacecraft using RSS == Cassini–Huygens Mariner 2, 4,5,6,7,9, and 10 Voyager 1 and 2 MESSENGER Venus Express == Functions == Determine composition of gas clouds such as atmospheres, solar coronas. Characterize gravitational fields Estimate masses of celestial satellites that do not have satellites of their own. To estimate particle size of particle fields Estimate densities of ion fields. == Specifications == Given a deep space network (DSN) of receivers and/or transmitters. A Ka-band traveling wave tube amplifier (K-TWTA) amplifies signals to a transmitting antenna to be received by a distal radio telescope. Ka-band translator (KAT) receives signal from a high gain antenna and retransmits the signal back to DSN. In this way the phase and phase-shift resulting from signal modification Ka-band exciter (KEX) it supplies telemetry data. S-band transmitter is used for radio science experiments. The transmitter receives signal from the RFS, amplifies and multiplies the signal, sending a 2290 MHz signal to the antenna. Filter microwave emitter allow only microwaves of a given frequency to be emitted, there is a polarizing element. There are two-bypass filters and a wave-guide. The bypass filters allow different feed polarizations, receiving and transmitting. == References ==
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https://en.wikipedia.org/wiki/Radio_science_subsystem
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Cognitive science is the interdisciplinary, scientific study of the mind and its processes. It examines the nature, the tasks, and the functions of cognition (in a broad sense). Mental faculties of concern to cognitive scientists include perception, memory, attention, reasoning, language, and emotion. To understand these faculties, cognitive scientists borrow from fields such as psychology, economics, artificial intelligence, neuroscience, linguistics, and anthropology. The typical analysis of cognitive science spans many levels of organization, from learning and decision-making to logic and planning; from neural circuitry to modular brain organization. One of the fundamental concepts of cognitive science is that "thinking can best be understood in terms of representational structures in the mind and computational procedures that operate on those structures." == History == The cognitive sciences began as an intellectual movement in the 1950s, called the cognitive revolution. Cognitive science has a prehistory traceable back to ancient Greek philosophical texts (see Plato's Meno and Aristotle's De Anima); Modern philosophers such as Descartes, David Hume, Immanuel Kant, Benedict de Spinoza, Nicolas Malebranche, Pierre Cabanis, Leibniz and John Locke, rejected scholasticism while mostly having never read Aristotle, and they were working with an entirely different set of tools and core concepts than those of the cognitive scientist. The modern culture of cognitive science can be traced back to the early cyberneticists in the 1930s and 1940s, such as Warren McCulloch and Walter Pitts, who sought to understand the organizing principles of the mind. McCulloch and Pitts developed the first variants of what are now known as artificial neural networks, models of computation inspired by the structure of biological neural networks. Another precursor was the early development of the theory of computation and the digital computer in the 1940s and 1950s. Kurt Gödel, Alonzo Church, Alan Turing, and John von Neumann were instrumental in these developments. The modern computer, or Von Neumann machine, would play a central role in cognitive science, both as a metaphor for the mind, and as a tool for investigation. The first instance of cognitive science experiments being done at an academic institution took place at MIT Sloan School of Management, established by J.C.R. Licklider working within the psychology department and conducting experiments using computer memory as models for human cognition. In 1959, Noam Chomsky published a scathing review of B. F. Skinner's book Verbal Behavior. At the time, Skinner's behaviorist paradigm dominated the field of psychology within the United States. Most psychologists focused on functional relations between stimulus and response, without positing internal representations. Chomsky argued that in order to explain language, we needed a theory like generative grammar, which not only attributed internal representations but characterized their underlying order. The term cognitive science was coined by Christopher Longuet-Higgins in his 1973 commentary on the Lighthill report, which concerned the then-current state of artificial intelligence research. In the same decade, the journal Cognitive Science and the Cognitive Science Society were founded. The founding meeting of the Cognitive Science Society was held at the University of California, San Diego in 1979, which resulted in cognitive science becoming an internationally visible enterprise. In 1972, Hampshire College started the first undergraduate education program in Cognitive Science, led by Neil Stillings. In 1982, with assistance from Professor Stillings, Vassar College became the first institution in the world to grant an undergraduate degree in Cognitive Science. In 1986, the first Cognitive Science Department in the world was founded at the University of California, San Diego. In the 1970s and early 1980s, as access to computers increased, artificial intelligence research expanded. Researchers such as Marvin Minsky would write computer programs in languages such as LISP to attempt to formally characterize the steps that human beings went through, for instance, in making decisions and solving problems, in the hope of better understanding human thought, and also in the hope of creating artificial minds. This approach is known as "symbolic AI". Eventually the limits of the symbolic AI research program became apparent. For instance, it seemed to be unrealistic to comprehensively list human knowledge in a form usable by a symbolic computer program. The late 80s and 90s saw the rise of neural networks and connectionism as a research paradigm. Under this point of view, often attributed to James McClelland and David Rumelhart, the mind could be characterized as a set of complex associations, represented as a layered network. Critics argue that there are some phenomena which are better captured by symbolic models, and that connectionist models are often so complex as to have little explanatory power. Recently symbolic and connectionist models have been combined, making it possible to take advantage of both forms of explanation. While both connectionism and symbolic approaches have proven useful for testing various hypotheses and exploring approaches to understanding aspects of cognition and lower level brain functions, neither are biologically realistic and therefore, both suffer from a lack of neuroscientific plausibility. Connectionism has proven useful for exploring computationally how cognition emerges in development and occurs in the human brain, and has provided alternatives to strictly domain-specific / domain general approaches. For example, scientists such as Jeff Elman, Liz Bates, and Annette Karmiloff-Smith have posited that networks in the brain emerge from the dynamic interaction between them and environmental input. Recent developments in quantum computation, including the ability to run quantum circuits on quantum computers such as IBM Quantum Platform, has accelerated work using elements from quantum mechanics in cognitive models. == Principles == === Levels of analysis === A central tenet of cognitive science is that a complete understanding of the mind/brain cannot be attained by studying only a single level. An example would be the problem of remembering a phone number and recalling it later. One approach to understanding this process would be to study behavior through direct observation, or naturalistic observation. A person could be presented with a phone number and be asked to recall it after some delay of time; then the accuracy of the response could be measured. Another approach to measure cognitive ability would be to study the firings of individual neurons while a person is trying to remember the phone number. Neither of these experiments on its own would fully explain how the process of remembering a phone number works. Even if the technology to map out every neuron in the brain in real-time were available and it were known when each neuron fired it would still be impossible to know how a particular firing of neurons translates into the observed behavior. Thus an understanding of how these two levels relate to each other is imperative. Francisco Varela, in The Embodied Mind: Cognitive Science and Human Experience, argues that "the new sciences of the mind need to enlarge their horizon to encompass both lived human experience and the possibilities for transformation inherent in human experience". On the classic cognitivist view, this can be provided by a functional level account of the process. Studying a particular phenomenon from multiple levels creates a better understanding of the processes that occur in the brain to give rise to a particular behavior. Marr gave a famous description of three levels of analysis: The computational theory, specifying the goals of the computation; Representation and algorithms, giving a representation of the inputs and outputs and the algorithms which transform one into the other; and The hardware implementation, or how algorithm and representation may be physically realized. === Interdisciplinary nature === Cognitive science is an interdisciplinary field with contributors from various fields, including psychology, neuroscience, linguistics, philosophy of mind, computer science, anthropology and biology. Cognitive scientists work collectively in hope of understanding the mind and its interactions with the surrounding world much like other sciences do. The field regards itself as compatible with the physical sciences and uses the scientific method as well as simulation or modeling, often comparing the output of models with aspects of human cognition. Similarly to the field of psychology, there is some doubt whether there is a unified cognitive science, which have led some researchers to prefer 'cognitive sciences' in plural. Many, but not all, who consider themselves cognitive scientists hold a functionalist view of the mind—the view that mental states and processes should be explained by their function – what they do. According to the multiple realizability account of functionalism, even non-human systems such as robots and computers can be ascribed as having cognition. === Cognitive science, the term === The term "cognitive" in "cognitive science" is used for "any kind of mental operation or structure that can be studied in precise terms" (Lakoff and Johnson, 1999). This conceptualization is very broad, and should not be confused with how "cognitive" is used in some traditions of analytic philosophy, where "cognitive" has to do only with formal rules and truth-conditional semantics. The earliest entries for the word "cognitive" in the OED take it to mean roughly "pertaining to the action or process of knowing". The first entry, from 1586, shows the word was at one time used in the context of discussions of Platonic theories of knowledge. Most in cognitive science, however, presumably do not believe their field is the study of anything as certain as the knowledge sought by Plato. == Scope == Cognitive science is a large field, and covers a wide array of topics on cognition. However, it should be recognized that cognitive science has not always been equally concerned with every topic that might bear relevance to the nature and operation of minds. Classical cognitivists have largely de-emphasized or avoided social and cultural factors, embodiment, emotion, consciousness, animal cognition, and comparative and evolutionary psychologies. However, with the decline of behaviorism, internal states such as affects and emotions, as well as awareness and covert attention became approachable again. For example, situated and embodied cognition theories take into account the current state of the environment as well as the role of the body in cognition. With the newfound emphasis on information processing, observable behavior was no longer the hallmark of psychological theory, but the modeling or recording of mental states. Below are some of the main topics that cognitive science is concerned with; see List of cognitive science topics for a more exhaustive list. === Artificial intelligence === Artificial intelligence (AI) involves the study of cognitive phenomena in machines. One of the practical goals of AI is to implement aspects of human intelligence in computers. Computers are also widely used as a tool with which to study cognitive phenomena. Computational modeling uses simulations to study how human intelligence may be structured. (See § Computational modeling.) There is some debate in the field as to whether the mind is best viewed as a huge array of small but individually feeble elements (i.e. neurons), or as a collection of higher-level structures such as symbols, schemes, plans, and rules. The former view uses connectionism to study the mind, whereas the latter emphasizes symbolic artificial intelligence. One way to view the issue is whether it is possible to accurately simulate a human brain on a computer without accurately simulating the neurons that make up the human brain. === Attention === Attention is the selection of important information. The human mind is bombarded with millions of stimuli and it must have a way of deciding which of this information to process. Attention is sometimes seen as a spotlight, meaning one can only shine the light on a particular set of information. Experiments that support this metaphor include the dichotic listening task (Cherry, 1957) and studies of inattentional blindness (Mack and Rock, 1998). In the dichotic listening task, subjects are bombarded with two different messages, one in each ear, and told to focus on only one of the messages. At the end of the experiment, when asked about the content of the unattended message, subjects cannot report it. The psychological construct of attention is sometimes confused with the concept of intentionality due to some degree of semantic ambiguity in their definitions. At the beginning of experimental research on attention, Wilhelm Wundt defined this term as "that psychical process, which is operative in the clear perception of the narrow region of the content of consciousness." His experiments showed the limits of attention in space and time, which were 3-6 letters during an exposition of 1/10 s. Because this notion develops within the framework of the original meaning during a hundred years of research, the definition of attention would reflect the sense when it accounts for the main features initially attributed to this term – it is a process of controlling thought that continues over time. While intentionality is the power of minds to be about something, attention is the concentration of awareness on some phenomenon during a period of time, which is necessary to elevate the clear perception of the narrow region of the content of consciousness and which is feasible to control this focus in mind. The significance of knowledge about the scope of attention for studying cognition is that it defines the intellectual functions of cognition such as apprehension, judgment, reasoning, and working memory. The development of attention scope increases the set of faculties responsible for the mind relies on how it perceives, remembers, considers, and evaluates in making decisions. The ground of this statement is that the more details (associated with an event) the mind may grasp for their comparison, association, and categorization, the closer apprehension, judgment, and reasoning of the event are in accord with reality. According to Latvian professor Sandra Mihailova and professor Igor Val Danilov, the more elements of the phenomenon (or phenomena ) the mind can keep in the scope of attention simultaneously, the more significant number of reasonable combinations within that event it can achieve, enhancing the probability of better understanding features and particularity of the phenomenon (phenomena). For example, three items in the focal point of consciousness yield six possible combinations (3 factorial) and four items – 24 (4 factorial) combinations. The number of reasonable combinations becomes significant in the case of a focal point with six items with 720 possible combinations (6 factorial). === Bodily processes related to cognition === Embodied cognition approaches to cognitive science emphasize the role of body and environment in cognition. This includes both neural and extra-neural bodily processes, and factors that range from affective and emotional processes, to posture, motor control, proprioception, and kinaesthesis, to autonomic processes that involve heartbeat and respiration, to the role of the enteric gut microbiome. It also includes accounts of how the body engages with or is coupled to social and physical environments. 4E (embodied, embedded, extended and enactive) cognition includes a broad range of views about brain-body-environment interaction, from causal embeddedness to stronger claims about how the mind extends to include tools and instruments, as well as the role of social interactions, action-oriented processes, and affordances. 4E theories range from those closer to classic cognitivism (so-called "weak" embodied cognition) to stronger extended and enactive versions that are sometimes referred to as radical embodied cognitive science. A hypothesis of pre-perceptual multimodal integration supports embodied cognition approaches and converges two competing naturalist and constructivist viewpoints about cognition and the development of emotions. According to this hypothesis supported by empirical data, cognition and emotion development are initiated by the association of affective cues with stimuli responsible for triggering the neuronal pathways of simple reflexes. This pre-perceptual multimodal integration can succeed owing to neuronal coherence in mother-child dyads beginning from pregnancy. These cognitive-reflex and emotion-reflex stimuli conjunctions further form simple innate neuronal assemblies, shaping the cognitive and emotional neuronal patterns in statistical learning that are continuously connected with the neuronal pathways of reflexes. === Knowledge and processing of language === The ability to learn and understand language is an extremely complex process. Language is acquired within the first few years of life, and all humans under normal circumstances are able to acquire language proficiently. A major driving force in the theoretical linguistic field is discovering the nature that language must have in the abstract in order to be learned in such a fashion. Some of the driving research questions in studying how the brain itself processes language include: (1) To what extent is linguistic knowledge innate or learned?, (2) Why is it more difficult for adults to acquire a second-language than it is for infants to acquire their first-language?, and (3) How are humans able to understand novel sentences? The study of language processing ranges from the investigation of the sound patterns of speech to the meaning of words and whole sentences. Linguistics often divides language processing into orthography, phonetics, phonology, morphology, syntax, semantics, and pragmatics. Many aspects of language can be studied from each of these components and from their interaction. The study of language processing in cognitive science is closely tied to the field of linguistics. Linguistics was traditionally studied as a part of the humanities, including studies of history, art and literature. In the last fifty years or so, more and more researchers have studied knowledge and use of language as a cognitive phenomenon, the main problems being how knowledge of language can be acquired and used, and what precisely it consists of. Linguists have found that, while humans form sentences in ways apparently governed by very complex systems, they are remarkably unaware of the rules that govern their own speech. Thus linguists must resort to indirect methods to determine what those rules might be, if indeed rules as such exist. In any event, if speech is indeed governed by rules, they appear to be opaque to any conscious consideration. === Learning and development === Learning and development are the processes by which we acquire knowledge and information over time. Infants are born with little or no knowledge (depending on how knowledge is defined), yet they rapidly acquire the ability to use language, walk, and recognize people and objects. Research in learning and development aims to explain the mechanisms by which these processes might take place. A major question in the study of cognitive development is the extent to which certain abilities are innate or learned. This is often framed in terms of the nature and nurture debate. The nativist view emphasizes that certain features are innate to an organism and are determined by its genetic endowment. The empiricist view, on the other hand, emphasizes that certain abilities are learned from the environment. Although clearly both genetic and environmental input is needed for a child to develop normally, considerable debate remains about how genetic information might guide cognitive development. In the area of language acquisition, for example, some (such as Steven Pinker) have argued that specific information containing universal grammatical rules must be contained in the genes, whereas others (such as Jeffrey Elman and colleagues in Rethinking Innateness) have argued that Pinker's claims are biologically unrealistic. They argue that genes determine the architecture of a learning system, but that specific "facts" about how grammar works can only be learned as a result of experience. === Memory === Memory allows us to store information for later retrieval. Memory is often thought of as consisting of both a long-term and short-term store. Long-term memory allows us to store information over prolonged periods (days, weeks, years). We do not yet know the practical limit of long-term memory capacity. Short-term memory allows us to store information over short time scales (seconds or minutes). Memory is also often grouped into declarative and procedural forms. Declarative memory—grouped into subsets of semantic and episodic forms of memory—refers to our memory for facts and specific knowledge, specific meanings, and specific experiences (e.g. "Are apples food?", or "What did I eat for breakfast four days ago?"). Procedural memory allows us to remember actions and motor sequences (e.g. how to ride a bicycle) and is often dubbed implicit knowledge or memory . Cognitive scientists study memory just as psychologists do, but tend to focus more on how memory bears on cognitive processes, and the interrelationship between cognition and memory. One example of this could be, what mental processes does a person go through to retrieve a long-lost memory? Or, what differentiates between the cognitive process of recognition (seeing hints of something before remembering it, or memory in context) and recall (retrieving a memory, as in "fill-in-the-blank")? === Perception and action === Perception is the ability to take in information via the senses, and process it in some way. Vision and hearing are two dominant senses that allow us to perceive the environment. Some questions in the study of visual perception, for example, include: (1) How are we able to recognize objects?, (2) Why do we perceive a continuous visual environment, even though we only see small bits of it at any one time? One tool for studying visual perception is by looking at how people process optical illusions. The image on the right of a Necker cube is an example of a bistable percept, that is, the cube can be interpreted as being oriented in two different directions. The study of haptic (tactile), olfactory, and gustatory stimuli also fall into the domain of perception. Action is taken to refer to the output of a system. In humans, this is accomplished through motor responses. Spatial planning and movement, speech production, and complex motor movements are all aspects of action. === Consciousness === == Research methods == Many different methodologies are used to study cognitive science. As the field is highly interdisciplinary, research often cuts across multiple areas of study, drawing on research methods from psychology, neuroscience, computer science and systems theory. === Behavioral experiments === In order to have a description of what constitutes intelligent behavior, one must study behavior itself. This type of research is closely tied to that in cognitive psychology and psychophysics. By measuring behavioral responses to different stimuli, one can understand something about how those stimuli are processed. Lewandowski & Strohmetz (2009) reviewed a collection of innovative uses of behavioral measurement in psychology including behavioral traces, behavioral observations, and behavioral choice. Behavioral traces are pieces of evidence that indicate behavior occurred, but the actor is not present (e.g., litter in a parking lot or readings on an electric meter). Behavioral observations involve the direct witnessing of the actor engaging in the behavior (e.g., watching how close a person sits next to another person). Behavioral choices are when a person selects between two or more options (e.g., voting behavior, choice of a punishment for another participant). Reaction time. The time between the presentation of a stimulus and an appropriate response can indicate differences between two cognitive processes, and can indicate some things about their nature. For example, if in a search task the reaction times vary proportionally with the number of elements, then it is evident that this cognitive process of searching involves serial instead of parallel processing. Psychophysical responses. Psychophysical experiments are an old psychological technique, which has been adopted by cognitive psychology. They typically involve making judgments of some physical property, e.g. the loudness of a sound. Correlation of subjective scales between individuals can show cognitive or sensory biases as compared to actual physical measurements. Some examples include: sameness judgments for colors, tones, textures, etc. threshold differences for colors, tones, textures, etc. Eye tracking. This methodology is used to study a variety of cognitive processes, most notably visual perception and language processing. The fixation point of the eyes is linked to an individual's focus of attention. Thus, by monitoring eye movements, we can study what information is being processed at a given time. Eye tracking allows us to study cognitive processes on extremely short time scales. Eye movements reflect online decision making during a task, and they provide us with some insight into the ways in which those decisions may be processed. === Brain imaging === Brain imaging involves analyzing activity within the brain while performing various tasks. This allows us to link behavior and brain function to help understand how information is processed. Different types of imaging techniques vary in their temporal (time-based) and spatial (location-based) resolution. Brain imaging is often used in cognitive neuroscience. Single-photon emission computed tomography and positron emission tomography. SPECT and PET use radioactive isotopes, which are injected into the subject's bloodstream and taken up by the brain. By observing which areas of the brain take up the radioactive isotope, we can see which areas of the brain are more active than other areas. PET has similar spatial resolution to fMRI, but it has extremely poor temporal resolution. Electroencephalography. EEG measures the electrical fields generated by large populations of neurons in the cortex by placing a series of electrodes on the scalp of the subject. This technique has an extremely high temporal resolution, but a relatively poor spatial resolution. Functional magnetic resonance imaging. fMRI measures the relative amount of oxygenated blood flowing to different parts of the brain. More oxygenated blood in a particular region is assumed to correlate with an increase in neural activity in that part of the brain. This allows us to localize particular functions within different brain regions. fMRI has moderate spatial and temporal resolution. Optical imaging. This technique uses infrared transmitters and receivers to measure the amount of light reflectance by blood near different areas of the brain. Since oxygenated and deoxygenated blood reflects light by different amounts, we can study which areas are more active (i.e., those that have more oxygenated blood). Optical imaging has moderate temporal resolution, but poor spatial resolution. It also has the advantage that it is extremely safe and can be used to study infants' brains. Magnetoencephalography. MEG measures magnetic fields resulting from cortical activity. It is similar to EEG, except that it has improved spatial resolution since the magnetic fields it measures are not as blurred or attenuated by the scalp, meninges and so forth as the electrical activity measured in EEG is. MEG uses SQUID sensors to detect tiny magnetic fields. === Computational modeling === Computational models require a mathematically and logically formal representation of a problem. Computer models are used in the simulation and experimental verification of different specific and general properties of intelligence. Computational modeling can help us understand the functional organization of a particular cognitive phenomenon. Approaches to cognitive modeling can be categorized as: (1) symbolic, on abstract mental functions of an intelligent mind by means of symbols; (2) subsymbolic, on the neural and associative properties of the human brain; and (3) across the symbolic–subsymbolic border, including hybrid. Symbolic modeling evolved from the computer science paradigms using the technologies of knowledge-based systems, as well as a philosophical perspective (e.g. "Good Old-Fashioned Artificial Intelligence" (GOFAI)). They were developed by the first cognitive researchers and later used in information engineering for expert systems. Since the early 1990s it was generalized in systemics for the investigation of functional human-like intelligence models, such as personoids, and, in parallel, developed as the SOAR environment. Recently, especially in the context of cognitive decision-making, symbolic cognitive modeling has been extended to the socio-cognitive approach, including social and organizational cognition, interrelated with a sub-symbolic non-conscious layer. Subsymbolic modeling includes connectionist/neural network models. Connectionism relies on the idea that the mind/brain is composed of simple nodes and its problem-solving capacity derives from the connections between them. Neural nets are textbook implementations of this approach. Some critics of this approach feel that while these models approach biological reality as a representation of how the system works, these models lack explanatory powers because, even in systems endowed with simple connection rules, the emerging high complexity makes them less interpretable at the connection-level than they apparently are at the macroscopic level. Other approaches gaining in popularity include (1) dynamical systems theory, (2) mapping symbolic models onto connectionist models (Neural-symbolic integration or hybrid intelligent systems), and (3) and Bayesian models, which are often drawn from machine learning. All the above approaches tend either to be generalized to the form of integrated computational models of a synthetic/abstract intelligence (i.e. cognitive architecture) in order to be applied to the explanation and improvement of individual and social/organizational decision-making and reasoning or to focus on single simulative programs (or microtheories/"middle-range" theories) modelling specific cognitive faculties (e.g. vision, language, categorization etc.). === Neurobiological methods === Research methods borrowed directly from neuroscience and neuropsychology can also help us to understand aspects of intelligence. These methods allow us to understand how intelligent behavior is implemented in a physical system. Single-unit recording Direct brain stimulation Animal models Postmortem studies == Key findings == Cognitive science has given rise to models of human cognitive bias and risk perception, and has been influential in the development of behavioral finance, part of economics. It has also given rise to a new theory of the philosophy of mathematics (related to denotational mathematics), and many theories of artificial intelligence, persuasion and coercion. It has made its presence known in the philosophy of language and epistemology as well as constituting a substantial wing of modern linguistics. Fields of cognitive science have been influential in understanding the brain's particular functional systems (and functional deficits) ranging from speech production to auditory processing and visual perception. It has made progress in understanding how damage to particular areas of the brain affect cognition, and it has helped to uncover the root causes and results of specific dysfunction, such as dyslexia, anopsia, and hemispatial neglect. == Notable researchers == Some of the more recognized names in cognitive science are usually either the most controversial or the most cited. Within philosophy, some familiar names include Daniel Dennett, who writes from a computational systems perspective, John Searle, known for his controversial Chinese room argument, and Jerry Fodor, who advocates functionalism. Others include David Chalmers, who advocates Dualism and is also known for articulating the hard problem of consciousness, and Douglas Hofstadter, famous for writing Gödel, Escher, Bach, which questions the nature of words and thought. In the realm of linguistics, Noam Chomsky and George Lakoff have been influential (both have also become notable as political commentators). In artificial intelligence, Marvin Minsky, Herbert A. Simon, and Allen Newell are prominent. Popular names in the discipline of psychology include George A. Miller, James McClelland, Philip Johnson-Laird, Lawrence Barsalou, Vittorio Guidano, Howard Gardner and Steven Pinker. Anthropologists Dan Sperber, Edwin Hutchins, Bradd Shore, James Wertsch and Scott Atran, have been involved in collaborative projects with cognitive and social psychologists, political scientists and evolutionary biologists in attempts to develop general theories of culture formation, religion, and political association. Computational theories (with models and simulations) have also been developed, by David Rumelhart, James McClelland and Philip Johnson-Laird. == Epistemics == Epistemics is a term coined in 1969 by the University of Edinburgh with the foundation of its School of Epistemics. Epistemics is to be distinguished from epistemology in that epistemology is the philosophical theory of knowledge, whereas epistemics signifies the scientific study of knowledge. Christopher Longuet-Higgins has defined it as "the construction of formal models of the processes (perceptual, intellectual, and linguistic) by which knowledge and understanding are achieved and communicated." In his 1978 essay "Epistemics: The Regulative Theory of Cognition", Alvin I. Goldman claims to have coined the term "epistemics" to describe a reorientation of epistemology. Goldman maintains that his epistemics is continuous with traditional epistemology and the new term is only to avoid opposition. Epistemics, in Goldman's version, differs only slightly from traditional epistemology in its alliance with the psychology of cognition; epistemics stresses the detailed study of mental processes and information-processing mechanisms that lead to knowledge or beliefs. In the mid-1980s, the School of Epistemics was renamed as The Centre for Cognitive Science (CCS). In 1998, CCS was incorporated into the University of Edinburgh's School of Informatics. == Binding problem in cognitive science == One of the core aims of cognitive science is to achieve an integrated theory of cognition. This requires integrative mechanisms explaining how the information processing that occurs simultaneously in spatially segregated (sub-)cortical areas in the brain is coordinated and bound together to give rise to coherent perceptual and symbolic representations. One approach is to solve this "Binding problem" (that is, the problem of dynamically representing conjunctions of informational elements, from the most basic perceptual representations ("feature binding") to the most complex cognitive representations, like symbol structures ("variable binding")), by means of integrative synchronization mechanisms. In other words, one of the coordinating mechanisms appears to be the temporal (phase) synchronization of neural activity based on dynamical self-organizing processes in neural networks, described by the Binding-by-synchrony (BBS) Hypothesis from neurophysiology. Connectionist cognitive neuroarchitectures have been developed that use integrative synchronization mechanisms to solve this binding problem in perceptual cognition and in language cognition. In perceptual cognition the problem is to explain how elementary object properties and object relations, like the object color or the object form, can be dynamically bound together or can be integrated to a representation of this perceptual object by means of a synchronization mechanism ("feature binding", "feature linking"). In language cognition the problem is to explain how semantic concepts and syntactic roles can be dynamically bound together or can be integrated to complex cognitive representations like systematic and compositional symbol structures and propositions by means of a synchronization mechanism ("variable binding") (see also the "Symbolism vs. connectionism debate" in connectionism). However, despite significant advances in understanding the integrated theory of cognition (specifically the Binding problem), the debate on this issue of beginning cognition is still in progress. From the different perspectives noted above, this problem can be reduced to the issue of how organisms at the simple reflexes stage of development overcome the threshold of the environmental chaos of sensory stimuli: electromagnetic waves, chemical interactions, and pressure fluctuations. The so-called Primary Data Entry (PDE) thesis poses doubts about the ability of such an organism to overcome this cue threshold on its own. In terms of mathematical tools, the PDE thesis underlines the insuperable high threshold of the cacophony of environmental stimuli (the stimuli noise) for young organisms at the onset of life. It argues that the temporal (phase) synchronization of neural activity based on dynamical self-organizing processes in neural networks, any dynamical bound together or integration to a representation of the perceptual object by means of a synchronization mechanism can not help organisms in distinguishing relevant cue (informative stimulus) for overcome this noise threshold. == See also == Outlines Outline of human intelligence – topic tree presenting the traits, capacities, models, and research fields of human intelligence, and more. Outline of thought – topic tree that identifies many types of thoughts, types of thinking, aspects of thought, related fields, and more. == References == == External links == Media related to Cognitive science at Wikimedia Commons Quotations related to Cognitive science at Wikiquote Learning materials related to Cognitive science at Wikiversity "Cognitive Science" on the Stanford Encyclopedia of Philosophy Cognitive Science Society Cognitive Science Movie Index: A broad list of movies showcasing themes in the Cognitive Sciences Archived 4 September 2015 at the Wayback Machine List of leading thinkers in cognitive science
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https://en.wikipedia.org/wiki/Cognitive_science
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S.C.I.E.N.C.E. is the second studio album by American rock band Incubus. It was released on September 9, 1997, by Epic and Immortal Records. The album was certified gold by the RIAA, and is the second and final release to feature Gavin Koppel (known as DJ Lyfe), who first appeared on the 1997 Enjoy Incubus EP. It has been occasionally considered the band's proper debut album, due to the nature of their independent release Fungus Amongus. == Background == === Production === After recording their independent debut album Fungus Amongus (1995), Incubus signed a seven-record deal with Epic/Sony-affiliated Immortal Records in 1996. An EP titled Enjoy Incubus was released by Epic/Immortal at the beginning of 1997, and Incubus would go on a European tour with labelmates Korn and The Urge for the next few months. With Enjoy Incubus, the label's strategy was to build the band's fanbase through touring rather than radio airplay. One of the first things the band had done after getting signed was buying new instruments, which would be used on future recordings. Drummer José Pasillas said that the band's old instruments were "falling apart". Guitarist Mike Einziger had previously been using an Ibanez RG570, and spent his money from the record company to purchase a Paul Reed Smith guitar. The four founding band members were in their early 20s at this point, and dropped out of school once getting signed, with Pasillas recalling "before then, each one of us were enrolled in schools because there was part of us that wanted to appease our parents. Getting signed was our okay to drop out of school." DJ Lyfe was older than the other four members and originally joined Incubus in late 1995, following the release of Fungus Amongus. Lyfe had first met Incubus at a live show in Hollywood, where he approached them about incorporating his music into the band, claiming that it might add an interesting dimension to their sound. Incubus's full-length major label debut S.C.I.E.N.C.E. would be recorded between May 1997 and June 1997. Singer Brandon Boyd said "S.C.I.E.N.C.E. was done in six weeks at 4th Street Recording, a very small, charming studio in Santa Monica. Very different experience, but very important on this band's existence." While the single "New Skin" originated a few years prior, Pasillas claimed in 2002 that for other songs they had two months to write the music. He added, "it was cool for us, because we had a lot of ideas and it was a pretty compressed amount of time. The circumstances weren't ideal — we were working in a dingy little rehearsal room — but at that time we didn't care. We were playing music for a living." According to Pasillas, they wrote 14 songs for S.C.I.E.N.C.E. in total. Unlike with later Incubus albums, the songs were recorded to tape, and the band wanted to avoid creating music that they wouldn't be able to perform live. During the recording, the band utilized older analogue gear that they described as having "phat sounds and spider webs." Incubus chose Jim Wirt to produce the album, since he had worked with them on earlier recordings. Einziger believed that Wirt helped encourage their creativity during the recording of S.C.I.E.N.C.E., saying in 1997, "he helps us come up with strange stuff and he likes it when we do. He doesn't try to change what we do, he tries to enhance it." Einziger added in the same interview, "when we signed our record deal and started working on this album, we were worried that someone would come along and tell us to hold back, and try and make our songs a little more palatable. But that never happened. They kinda just said, 'do whatever you want'. With that kind of support, we just let everything kind of run wild." Pasillas similarly noted the lack of outside influence in 2017, saying "we didn’t have label people coming in hovering above us making sure we weren't wasting money. We were left to our own devices and we worked well that way." In a 2018 interview with Australian magazine HEAVY, Boyd remembered "when we wrote S.C.I.E.N.C.E. we didn't know about any songwriting rules. It was like a chopped salad, schizophrenic album put together and we did it because we just didn’t know any better. We were just having a good time." He also believes that Incubus still hadn't found a distinct voice of their own yet, saying in 2022 that they sounded like the offspring from a "crazy orgy" between Faith No More, Mr. Bungle, Red Hot Chili Peppers, Björk and other artists. Einziger told Guitar World in 2011 that the band developed more of their own sound on later albums since they had experienced more of the world through touring by then, and that on S.C.I.E.N.C.E. "[we sounded] like what we had been listening to." For the liner notes, every member except DJ Lyfe and bassist Alex Katunich used a pseudonym made specifically for the album, with Boyd's being "Cornelius", Einziger's being "Jawa" and Pasillas's being "Badmammajamma". The concept of using pseudonyms was carried over from Fungus Amongus and Enjoy Incubus, where the members had been using several different ones created specifically for those releases, including the pseudonyms "Happy Knappy" and "Brandon of the Jungle" (used by Boyd), and the pseudonyms "Fabio" and "Dynamike" (used by Einziger). Katunich used the pseudonym "Dirk Lance" for all three of these releases, while DJ Lyfe used the pseudonym "Kid Lyfe" for Enjoy Incubus, before deciding to use his regular stage name for S.C.I.E.N.C.E.. Mastering work was done at Larrabee West Studios in Hollywood, California. When S.C.I.E.N.C.E. was in the process of being recorded and mastered, the band went on some local mini-tours, in addition to appearing on the soundtrack for the movie Spawn. The soundtrack was released on July 29, 1997, by Epic/Immortal, and featured a collaboration with DJ Greyboy called "Familiar". This song also briefly appeared in the movie itself, which was released to theaters on August 1, 1997. It samples the 1960 song "Theme for Doris", by jazz musician Tina Brooks. Boyd claimed in a 1997 Kerrang! interview that he had seen the Spawn movie, and described it as "a really shitty movie" with "a great soundtrack". That year, the song "Glass" was also featured on a 7 inch vinyl single with the song "Water & Solutions", by Epic/Immortal labelmates Far. "Water & Solutions" was taken from the album of the same name, which was recorded around the same time as S.C.I.E.N.C.E., but not released until March 1998. Incubus later toured with Far, and on promotional photos for 2001's Morning View, Einziger can be seen wearing a hoodie with the cover of their 1997 EP Soon. === Musical style and influences === Musically, S.C.I.E.N.C.E. has been described as alternative metal, nu metal, funk metal, and rap metal. The album incorporates elements of multiple genres, including jazz, heavy metal, funk, hip hop, techno, and electro. It was labelled as "schizo funk/jazz/metal" by Spin in 2001. In September 1997, Hits magazine called the album's lighter songs "loungey" and "almost reminiscent of Jamiroquai". "Magic Medicine", described as a trip hop track, samples a recorded reading of a children's book. Paul Elliot of Kerrang! wrote in May 1998 that "at their lightest — on 'Summer Romance (Anti-Gravity Love Song)' for example — Incubus are deliciously, irresistibly funky. And at their heaviest — notably on the frantic 'Favorite Things' — they're reminiscent of Faith No More at their wildest." Elliot added that people who were upset about the split of Faith No More "[should go along] to an Incubus gig." The Daily Nebraskan referred to them as a "funk-heavy foursome" in 1998, while Billboard labelled them a funk rock band in December 1997. According to Rolling Stone writer Rob Kemp, S.C.I.E.N.C.E. "links funk metal to the rap-metal". Though sometimes retrospectively associated with it, the term nu metal was not yet in usage when S.C.I.E.N.C.E. was released, but rather terms such as alternative metal, funk metal and rap metal. In 1997, Boyd said "people are real quick to put labels on music, so I'm sure they're going to do that with us. But we think we're doing something cool, and judging from the responses that we've gotten from all over the world, others do too." Einziger has since stated that Incubus were not part of the same Southern Californian scene as bands like Korn and System of a Down during their independent years, despite having similar influences. In interviews from the late 2010s and 2020s, Boyd has said that he dislikes the nu metal label and doesn't consider the band's early work to be part of the movement. In a 2022 Metal Hammer interview, he remarked, "we weren’t trying to fit into a particular niche at a particular time. We were just kids being influenced by a small handful of bands that we grew up with." Revolver describe Brandon Boyd as vocally "drawing on the eccentric funk-rap" of Faith No More, Primus and Red Hot Chili Peppers. They consider him to have a "goofy yet also badass presence" on S.C.I.E.N.C.E. Boyd has cited Faith No More's vocalist Mike Patton as being an influence from since he was an early teenager, as well as Patton's side project Mr. Bungle, who were similarly known for mixing a wide array of genres. Through Mr. Bungle, Boyd also went on to become a fan of avant-garde musician John Zorn, who produced their 1991 debut album. In a 2003 interview with the Philippine Daily Inquirer, Boyd said that around this period, both he and Einziger gravitated towards more experimental artists that "you'll never hear on the radio". Alex Katunich uses a slap bass playing style on the album, and has said he was influenced by funk music since he was a young child, and got an album of Disney songs done in disco style. When he became a teenager, he said Faith No More's 1989 album The Real Thing began influencing him, in addition to becoming influenced by Mr. Bungle and other funk metal bands, such as Infectious Grooves, Primus and Red Hot Chili Peppers. In a 1998 interview, Boyd was asked about whether Incubus was influenced by Faith No More, who had broken up in April of that year, and he commented, "there's a definite influence from Faith No More. All of us have been listening to that band since when we were really young. We were like 14 or something when that album [The Real Thing] came out. They were an awesome band, they did some really groundbreaking things in their time, and it's kind of a bummer to hear that they broke up." Boyd also noted in October 1997 that they were frequently compared to both Faith No More and the Red Hot Chili Peppers, saying "when people do try and compare us, it's usually with those two bands." In addition to these influences, the band became interested in emerging electronic genres like drum and bass around the making of S.C.I.E.N.C.E., with their previous full-length album Fungus Amongus having no influence from electronic genres. While playing at European festivals with Korn and The Urge during early 1997, they recall being exposed to foreign electronic acts such as The Chemical Brothers. During the subsequent S.C.I.E.N.C.E. tour, the band sometimes created improvisational pieces of drum and bass music in between their songs, and this was how the song "Nowhere Fast" originated, with it being recorded for their next album Make Yourself (1999). S.C.I.E.N.C.E. was also the band's first release to be written with turntables, since several of the songs on Enjoy Incubus were re-recordings of tracks from Fungus Amongus. In a 2000 interview, Boyd remembered that when Incubus first met DJ Lyfe and he suggested adding his instrument, they were intrigued by this idea. They decided to incorporate the instrument after only a single rehearsal with Lyfe, with Boyd recalling that "it just began to present itself as probably a very cool new instrument that could offer lots and lots of opportunities sonically." AllMusic describe the use of turntables as being the main hip hop element on the album, which primarily features melodic, sung vocals rather than rapping or other vocal styles such as screaming. The album utilizes other instruments also not traditionally associated with rock music, including the saxophone and the digeridoo and djembe (which originate from Australia and West Africa). Boyd can be heard playing the digeridoo at the beginning of the opening track "Redefine", and he would bring one with him on the tour for S.C.I.E.N.C.E.. === Songs === About the opening track "Redefine", Boyd said in 1997: "Redefine" is about the creation of your own reality and your own world. The metaphor I used was humans being like Magic Markers. For so long, they painted black and white pictures in their life because that's all they thought they could do. But they can paint with a different color and make a very vibrant and beautiful picture if they take control. On the single "New Skin", he further elaborated: In "New Skin", I attribute a scab to the present state of society. The way the scab looks in its worst state is gross and chaotic and horrible, that's now, but when it breaks away, there's a brand new piece of skin that's stronger than before. It's like creation out of chaos. The song "Favorite Things", according to Boyd, related to the topic of religion: "My Favorite Things" is my personal beliefs about religion and how it oppresses the things I enjoy the most. Unfortunately, the simplest things, such as thinking for myself, creating my own reality and being whatever the hell I want to be each day of my life, are a sin. To be a good Christian basically means to give up the reigns of your life and let some unseen force do it for you. "Favorite Things" also includes a sample of the 1959 track "Flamenco Fantasy", by easy listening group the 101 Strings Orchestra. The song has a similar title to "My Favorite Things", from the Mary Poppins musical and film, with both songs repeatedly mentioning their titles in the lyrics. However, it does not musically reference "My Favorite Things". The single "A Certain Shade of Green" has been described as being a song about procrastination. The line "Are you gonna stand around till 2012 A.D.?" is a reference to an interpretation of the Mayan calendar which dictated that the world would end on December 21, 2012. Boyd did not believe this to be true, but it was on his mind as his mother was researching it for a book called Maya Memory: The Glory That Was Palenque. While recording "Nebula", Boyd said in 1997, "we found out what it's like to actually plug a phaser pedal into the wall while it's on. It sounds like a laser gun, and that's the first sound you hear in 'Nebula'." He added that for the song, "we used these walkie-talkies for children that have this Slinky-like coil between them. When you talk through them and hit the coil, it makes this natural reverb, like talking in another dimension." "Summer Romance (Anti-Gravity Love Song)" was the first love ballad the band wrote, but was written in a less serious manner than later songs touching on similar subjects, such as "Stellar". It featured saxophonist Jeremy Wasser of Hoobastank, a band which grew up in the same neighborhood of Southern California. The members of Hoobastank had known Incubus since 1993, and through them were introduced to Jim Wirt in 1996, with Wirt going on to produce several Hoobastank recordings. At that time, Hoobastank were unsigned and also playing a funk metal-style of music inspired by bands like Faith No More and Mr. Bungle. By the time Hoobastank signed to Island Records in 2000, they got rid of Wasser and had changed their sound to a more straightforward rock style. The penultimate track "Deep Inside" is another of the lighter songs on the album, drawing heavily from funk music. However, it also has a short heavy metal section beginning roughly 3 minutes into the song. The lyrics reference being high on drugs at 3 A.M. in the morning, and as the song goes on the time progresses to 4 A.M. and eventually 5 A.M. "Deep Inside" stopped being performed live when Alex Katunich left Incubus at the beginning of April 2003, with the last known performance coming during December 2001. The closing track "Calgone" lyrically revolves around an alien abduction. It ends with a sound clip of the band arguing with DJ Lyfe (who is referred to by his real name of Gavin), for supposedly deleting a track they had been working on in the studio. On physical versions of the album, "Calgone" is followed by a hidden track called "Segue 1", which plays after 30 seconds of silence. The hidden track is also known as "Jose Loves Kate Moss, Part 1", and has been treated as a separate track on streaming sites such as Spotify. It begins with a sound recording at a morgue, and the pathologist is describing injuries a patient had sustained during a car crash on May 12, 1997. The hidden track goes on to feature several different sound samples and funk/electronic musical pieces. It samples sounds from the 1985 Sorcerer pinball machine and the song "Show Me Your Titz", from Hoobastank's 1997 demo Muffins. It also has an electronic piece in the style of Mozart's Toy Symphony, a sound sample of an unknown woman saying "is this the shit, or what?", and a short skit parodying The Karate Kid. === Title and artwork === In 1997, Einziger claimed that the title reflected the experimental nature of the album, and the creative freedom the band were given. He was quoted as saying, "our album is called S.C.I.E.N.C.E. because we were able to experiment. We were able to take our time and get everything to sound the way we wanted it to — weird science and energetic funk." It has also been mentioned by various band members that the acronym S.C.I.E.N.C.E. stands for Sailing Catamarans Is Every Nautical Captain's Ecstasy. "Sometimes, we just sit around and come up with these for laughs. In other words, there's not just one meaning, it's just food for thought," said Boyd in 1998. In other early interviews, band members claimed that the title stood for Stupid Cops Invade Everyone's Natural Chaotic Energy, Sounds Cool in Eyes Near Communistic Entities and Surreal Cats in Economics Never Communicate Estacticly. The cover art features a photo of the head of Boyd's father, who had earlier appeared on the cover of Enjoy Incubus. The source of the photos were unknown at the time, and the man on the cover of these releases came to be known as 'Chuck'. The cover is also the first to include the band's current logo, which has been used on every subsequent studio album (with the exception of A Crow Left of the Murder... and Light Grenades). == Touring and promotion == Shortly before the release of S.C.I.E.N.C.E., Incubus played a handful of shows with rap rock bands Phunk Junkeez and Shootyz Groove. To support the album, Incubus went on tour with 311 and Sugar Ray between October 1997 and December 1997. At that time, Sugar Ray were experiencing huge success with their single "Fly", which had been released in mid-1997, and while the tour was happening their album Floored was certified platinum for sales of over a million copies. Incubus was the least known act on this tour, and were initially only meant to perform on the first leg of it. However, the crowd response to them was so great that they were asked to stay for the rest of the tour. During late 1997, the album's first two singles "A Certain Shade of Green" and "Redefine" were released to radio. That year, a music video for "A Certain Shade of Green" was also made. In February 1998, DJ Lyfe was fired by the band, and was replaced by DJ Chris Kilmore. The reasoning given for his firing was because of creative and personal differences, and because Incubus could no longer be a "productive family" with him in it. Prior to finding Kilmore, the band were in a state of limbo for a week, since they were unsure whether to add another fifth member or not. Kilmore was originally from Harrisburg, Pennsylvania, and had moved to Los Angeles, where he was struggling to support himself. He recalled sometimes not having enough money for electricity, telling Spin in 2001 that "It was cool, I just used candles at night." Kilmore was recommended by a friend of the band, and received a phone call on Friday February 13, 1998, where he was asked to audition. The audition took place the next day at the Sound Arena Studios in Reseda, Los Angeles. Kilmore remembered in 2019 that, "we sat around for 45 minutes just talking", adding "little did I know they were really just trying to get an idea of my personality. So we were talking everything from girls to aliens — all kinds of crazy stuff." During the last 15 minutes of the audition, Alex Katunich asked Kilmore to showcase his turntable skills. The other members of Incubus were impressed with Kilmore's playing and attitude towards life, with Einziger saying at the time, "after letting go of Gavin, I wasn't even sure if I wanted to acquire another member into the band, but then we met Chris and my opinion instantly changed." Following the end of the audition, Kilmore was given a cassette tape with 16 live recordings of Fungus Amongus and S.C.I.E.N.C.E. songs, as he had not heard any of the band's music at that point. In 2019, he recalled "later that night, they said, 'Can you come rehearse on Sunday?' I was like, 'No. It’s Valentine's Day, and I’m dating a Dominican redhead from Queens. So I cannot miss that.' So then, they were like, 'Well can you learn all these songs on Monday? Because we have a show on Tuesday.' I said yeah." Later in 1998, the third and final single "New Skin" was released. It had more of a promotional push than their previous two singles, and was their first full-scale marketed attempt at radio play. The cover for the CD release of the single included a group shot of the band, which had Kilmore instead of DJ Lyfe. That year, the new lineup played shows with Far, Limp Bizkit and British band One Minute Silence, in addition to performing at the 1998 edition of Ozzfest, and at the inaugural edition of Korn's Family Values Tour. According to Kilmore, the band played a total of 305 shows between the time he joined the band and the end of 1998. Incubus were able to get on Ozzfest 1998 since Ozzy Osbourne's son Jack liked the band's music. He also helped them get on the 2000 edition of Ozzfest, and at the urging of Sharon Osbourne and the Osbourne family, Incubus were chosen as a support act for some of Black Sabbath's reunion shows in January 1999. These shows included Pantera as another support act. In 2011, Einziger labelled the Osbournes as a "great family" and "fantastic people" for helping them get on these tours and supporting their music career. Einziger said he developed a friendship with the Osbourne family, and later in 2002 he and Pasillas worked on a song for Kelly Osbourne, the daughter of Ozzy Osbourne. Boyd recalled in 2021 that while touring with Black Sabbath in January 1999, the members of Pantera made fun of Incubus for wearing "baggy jeans", and at one point came to their dressing room with a platter that had new wrangler jeans and shots of Jack Daniel's whiskey. They urged them to try on the jeans and take a shot, with Boyd saying "I think I still have them somewhere and took a shot and almost threw up... never been a big drinker." Katunich later remembered that they had to play their heaviest songs while on metal-oriented tours such as these, in order to go over well with the crowds. During the touring cycle for S.C.I.E.N.C.E., they performed covers of "Powerslave" by Iron Maiden and "I Want You Back" by The Jackson Five. Years later, Michael Jackson's daughter Paris Jackson would open for Incubus. Boyd found out that his girlfriend who he had been dating since 1991 was having an affair while he was away on tour for S.C.I.E.N.C.E.. This event inspired the lyrical themes for Incubus's next album Make Yourself, which was noted for having a more accessible sound. Writing for Make Yourself began in early 1999, after the shows with Black Sabbath and Pantera. Regarding the change in direction on Make Yourself, Kilmore reflected in 2002, "I think what it was when we were touring behind S.C.I.E.N.C.E. was seeing all these other bands out there who were ripping off bands like Korn and the Deftones and 311, bands that we enjoy and that we love, I think when we realized that and we went into the studio to write Make Yourself, we said 'OK, let's not do that.'" Kilmore also recalls that, "during S.C.I.E.N.C.E. our crowd was all teenage kids wearing black and they were all men. Once 'Pardon Me' started getting some traction the crowd turned into half-girl crowds. Then when 'Stellar' and 'Drive' came out, those half-girl crowds became all screaming teenage girls in the front row." Einziger stated, "It was a very masculine time in music and we were associated with that. We would be playing Ozzfest tours with all these different bands who were our good friends and there was pressure to be like that. I think the tenderness and emotional side of the [later] music was a reaction to all that aggressive music that was happening at that time. Our reaction was to go in the other direction." According to Boyd in 2019 it "felt a little strange to be associated with some of the bands around that time who were very deeply misogynistic in their content and vibrationally kind of violent." == Release and reception == === Commercial response === In early 1999, S.C.I.E.N.C.E. and Enjoy Incubus were estimated to have sold a combined total of 200,000 units, with S.C.I.E.N.C.E. having sold around 150,000 copies at the beginning of 2000. Following their commercial breakthrough on Make Yourself, sales for S.C.I.E.N.C.E. began to increase. By 2001, it had sold 370,000 units in the United States. Epic/Immortal released a remastered version of the album during November 2001, and in the next year sales rose to 500,000. The remastering for the 2001 reissue was done at Marcussen Mastering, and it came as an enhanced CD that included the music video for "A Certain Shade of Green". Einziger said in 2011 that S.C.I.E.N.C.E. had sold nearly a million copies in the United States, and over a million when combined with international sales. === Critical response === Critics wrote favorably of the album's diverse style. Pitchfork gave it an 8.7 out of 10, stating "this CD successfully combines all sorts of shit without sounding like a mess. Here you have a song: it's got a phat-chunk bass beat twanging fast in back, some crazy electro squornks and bleeps coming and going, sudden snatches of full-blown guitar-jam, a rapid-fire Patton-esque vocalist (Brandon Boyd), all the while someone scratching vinyl and a drummer back there hammering merrily along." AllMusic reviewer David Thomas wrote that the band "manages to make their songs upbeat and danceable as well as tunes to headbang to. An admirable feat in a genre that tends to reward decibel levels instead of quality." On April 11, 1998, Darren Kerr of the Vancouver publication Drop D praised the album's incorporation of turntablism and trip hop. Kerr also noted similarities between Faith No More, who would announce their breakup just nine days later, writing "I would not dispute that Brandon of the Jungle's evil-lounge-singer-morphing-into-teeth-gnashing-maniac vocal style is emulative of Mike Patton. I also would not argue that a couple of these songs would not sound out of place alongside FNM tracks like 'Caffeine' or 'The Gentle Art of Making Enemies'. However, guitarist Michael Einzinger and bassist Alex Katunich are mining a groove vein uniquely their own." CMJ New Music Report wrote in their September 1997 review that, "you've heard this kind of hip hop/metal fusion from bands like Faith No More, Living Colour, Rage Against the Machine and Biohazard, but Incubus has got a bit more funk in its trunk than any of those artists." They noted the album "distinguishes itself from run-of-the-mill surf/skate metal by including a real live DJ (DJ Lyfe) who thrashes as hard on the turntable as the rest of the guys." The review goes on to state that the band manages to create "monstrous riffs", saying "S.C.I.E.N.C.E.'s most memorable songs are the ones in which Incubus proudly bares its metal muscles." Spin in 1998 pointed out not only the band's usage of turntables, but also their usage of the didgeridoo and djembe instruments. In his August 1998 review, Jason Hradil of The Lantern wrote that Boyd has "an intense voice similar to Faith No More's Mike Patton." He further wrote, "Incubus changes tempo and style at least two to three times per song" and "one thing I'll guarantee, is that these young men will bring home their report cards with an 'A' in science." In an October 1997 article focusing on an Incubus concert with 311 and Sugar Ray, Dan Nailen of the Moscow-Pullman Daily News had a positive view of the band's music. He wrote, "combining super-phat beats, rap-style turntable-scratching and crunchy heavy-metal guitar riffs, Incubus is nothing if not unique. Add to the musical mix the pilable vocals of frontman Brandon Boyd, reminiscent of Faith No More's Mike Patton, and you have music as interesting as Sugar Ray's is lame." Matt Peiken of Modern Drummer magazine awarded it three and a half out of five stars in March 1998. He praised the band's technical ability but noted a lack of focus on the album, saying "Incubus plays with listeners' minds in Faith No More-ish fashion [and] at times it's hard to tell whether the band is attempting to dish out some serious music or simply kicking out kitsch." === Legacy === Dylan P. Gadino of CMJ New Music Monthly reflected in November 2001 that Incubus "dropped their major-label debut, S.C.I.E.N.C.E., the same year as some nix-metal founders — 1997 also saw the releases of Limp Bizkit's Three Dollar Bill, Y'all and Sevendust's eponymous disc — yet Incubus's music [was] generally more inspired and layered than the efforts of their brooding counterparts." In November 2001, Amy Sciarretto of sister publication CMJ New Music Report further wrote, "Incubus was poised to be hard rock's bastard child of Faith No More and Primus thanks to its resident hottie Brandon Boyd's easy-on-the-ears emulation of Mike Patton and Dirk Lance's bass thwapping. But between 1997's S.C.I.E.N.C.E. and 1999's Make Yourself, the album that broke Incubus at rock radio, the band took a stylistic turn." Rolling Stone commented in 2002 that "they broke through to the Ozzfest crowd with 1997's eclectic funk-metal album, S.C.I.E.N.C.E.." The 2003 book The Rough Guide to Rock claimed that it was "better and far more accomplished" than their previous releases Enjoy Incubus and Fungus Amongus. The book additionally states that it "gave the band a much smoother, groove-oriented sound. Splashes of funk were offset with driving riffage and spiky turntable shrapnel, while Boyd's lyrics began to encompass a more intellectual world-view than your average rock star." In 2004, David Clayman of IGN called it "fairly impressive, considering the band's age and experience at the time of those recordings." That same year, Nick Romanow of the Daily Collegian reflected that with S.C.I.E.N.C.E., Incubus "had the potential to become the next Faith No More", noting that "the comparison was even heightened by charismatic frontman Brandon Boyd’s vocal similarities to Mike Patton, Faith No More’s innovative singer." He also said that by Morning View they had "abandoned their will to be as innovative as Faith No More". Vice in 2013 considered it to be their heaviest release, as well as "what a more elastic and bold Red Hot Chili Peppers could be like." Loudwire praised it in 2019, saying "before their music almost entirely mellowed out, Incubus were a high energy genre-bending band of misfits. The sophomore effort fused metal, hip-hop, trip-hop, funk, jazz and even a little bit of house music." On the album's 20th anniversary in 2017, Spin wrote that it mixes "cartoonish slap bass with bongwater-soaked guitar distortion [and] dubby drum-n-bass with samples from children’s audiobooks." They added, "you’d almost expect it to have died in a psychedelics-related car accident before it reached the distinguished age of 20." Geddy Lee of Canadian rock band Rush was a fan of the album, and at one point expressed interest in collaborating with Incubus. Tosin Abasi, guitarist of progressive metal band Animals as Leaders, has mentioned being influenced by it, with his band later touring with Incubus in 2022. The band's greatest hits releases The Essential Incubus (2012) and Playlist: The Very Best of Incubus (2013) both include songs from the album, while their initial greatest hits release Monuments and Melodies (2009) only included an acoustic version of "A Certain Shade of Green", which was not recorded during the S.C.I.E.N.C.E. era. In 2003, the song "Vitamin" was also featured in the horror film Final Destination 2. === Accolades === VH1 ranked the album tenth on their 2015 list of "The 12 Most Underrated Nu Metal Albums", while Revolver included it on a 2021 list of the "20 Essential Nu-Metal Albums". In 2020, Metal Hammer listed it as being one of the best metal albums released between 1996 and 1997, and also included it in their lists of the top 10 albums of 1997 and the top 20 best metal albums of 1997. When ranking Incubus's discography in 2020, Kerrang! placed S.C.I.E.N.C.E. third, remarking, "for fans of the band’s heavier, zanier leanings, this remains the high bar against which Incubus releases are now measured. Given the subsequent departures from this template, however, it’s likely those early adopters have been left disappointed. You could therefore argue that S.C.I.E.N.C.E. is something of a creative albatross around the band’s neck." In 2024, Ultimate Guitar included it on a list titled "10 Classic Albums That Defined the '90s Alternative Metal Scene". == Live performance == Incubus did not often perform songs from S.C.I.E.N.C.E. between the late 2000s and early 2010s, with Boyd telling Spin in 2017, "there was a period of years when we were knowingly rebelling against it, we were desperately trying to shake off the identity it had created around us. Our original fans would get mad, 'Why don’t you play more stuff from S.C.I.E.N.C.E.?' I think it only happened two or three years ago, when we were touring again, and started to revisit the songs casually in rehearsal studios and sound checks. We started to fall in love with them again. I think we just needed a friend break." He also said there are "tracks that are just kind of ridiculous, that we don’t really fuck with. One day we might." == Track listing == == Personnel == Incubus Brandon Boyd – lead vocals, percussion Mike Einziger – guitar, backing vocals Alex Katunich – bass Gavin Koppel – turntables José Pasillas – drums Additional musicians Charles Waltz – violin Jeremy Wasser – saxophone on "Summer Romance (Anti-Gravity Love Song)" Production Jim Wirt – producer Ulrich Wild – engineer CJ Eiriksson – engineer Donat Kazarinoff – engineer Matthew Kallen – assistant engineer Terry Date – mixing Stephen Marcussen – mastering, remastering Frank Harkins – art direction Chris McCann – photography == Charts == === Weekly charts === === Year-end charts === == Certifications == == References ==
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https://en.wikipedia.org/wiki/S.C.I.E.N.C.E.
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Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere, hydrosphere/cryosphere, atmosphere, and geosphere (or lithosphere). Earth science can be considered to be a branch of planetary science but with a much older history. == Geology == Geology is broadly the study of Earth's structure, substance, and processes. Geology is largely the study of the lithosphere, or Earth's surface, including the crust and rocks. It includes the physical characteristics and processes that occur in the lithosphere as well as how they are affected by geothermal energy. It incorporates aspects of chemistry, physics, and biology as elements of geology interact. Historical geology is the application of geology to interpret Earth history and how it has changed over time. Geochemistry studies the chemical components and processes of the Earth. Geophysics studies the physical properties of the Earth. Paleontology studies fossilized biological material in the lithosphere. Planetary geology studies geoscience as it pertains to extraterrestrial bodies. Geomorphology studies the origin of landscapes. Structural geology studies the deformation of rocks to produce mountains and lowlands. Resource geology studies how energy resources can be obtained from minerals. Environmental geology studies how pollution and contaminants affect soil and rock. Mineralogy is the study of minerals and includes the study of mineral formation, crystal structure, hazards associated with minerals, and the physical and chemical properties of minerals. Petrology is the study of rocks, including the formation and composition of rocks. Petrography is a branch of petrology that studies the typology and classification of rocks. == Earth's interior == Plate tectonics, mountain ranges, volcanoes, and earthquakes are geological phenomena that can be explained in terms of physical and chemical processes in the Earth's crust. Beneath the Earth's crust lies the mantle which is heated by the radioactive decay of heavy elements. The mantle is not quite solid and consists of magma which is in a state of semi-perpetual convection. This convection process causes the lithospheric plates to move, albeit slowly. The resulting process is known as plate tectonics. Areas of the crust where new crust is created are called divergent boundaries, those where it is brought back into the Earth are convergent boundaries and those where plates slide past each other, but no new lithospheric material is created or destroyed, are referred to as transform (or conservative) boundaries. Earthquakes result from the movement of the lithospheric plates, and they often occur near convergent boundaries where parts of the crust are forced into the earth as part of subduction. Plate tectonics might be thought of as the process by which the Earth is resurfaced. As the result of seafloor spreading, new crust and lithosphere is created by the flow of magma from the mantle to the near surface, through fissures, where it cools and solidifies. Through subduction, oceanic crust and lithosphere vehemently returns to the convecting mantle. Volcanoes result primarily from the melting of subducted crust material. Crust material that is forced into the asthenosphere melts, and some portion of the melted material becomes light enough to rise to the surface—giving birth to volcanoes. == Atmospheric science == Atmospheric science initially developed in the late-19th century as a means to forecast the weather through meteorology, the study of weather. Atmospheric chemistry was developed in the 20th century to measure air pollution and expanded in the 1970s in response to acid rain. Climatology studies the climate and climate change. The troposphere, stratosphere, mesosphere, thermosphere, and exosphere are the five layers which make up Earth's atmosphere. 75% of the mass in the atmosphere is located within the troposphere, the lowest layer. In all, the atmosphere is made up of about 78.0% nitrogen, 20.9% oxygen, and 0.92% argon, and small amounts of other gases including CO2 and water vapor. Water vapor and CO2 cause the Earth's atmosphere to catch and hold the Sun's energy through the greenhouse effect. This makes Earth's surface warm enough for liquid water and life. In addition to trapping heat, the atmosphere also protects living organisms by shielding the Earth's surface from cosmic rays. The magnetic field—created by the internal motions of the core—produces the magnetosphere which protects Earth's atmosphere from the solar wind. As the Earth is 4.5 billion years old, it would have lost its atmosphere by now if there were no protective magnetosphere. == Earth's magnetic field == == Hydrology == Hydrology is the study of the hydrosphere and the movement of water on Earth. It emphasizes the study of how humans use and interact with freshwater supplies. Study of water's movement is closely related to geomorphology and other branches of Earth science. Applied hydrology involves engineering to maintain aquatic environments and distribute water supplies. Subdisciplines of hydrology include oceanography, hydrogeology, ecohydrology, and glaciology. Oceanography is the study of oceans. Hydrogeology is the study of groundwater. It includes the mapping of groundwater supplies and the analysis of groundwater contaminants. Applied hydrogeology seeks to prevent contamination of groundwater and mineral springs and make it available as drinking water. The earliest exploitation of groundwater resources dates back to 3000 BC, and hydrogeology as a science was developed by hydrologists beginning in the 17th century. Ecohydrology is the study of ecological systems in the hydrosphere. It can be divided into the physical study of aquatic ecosystems and the biological study of aquatic organisms. Ecohydrology includes the effects that organisms and aquatic ecosystems have on one another as well as how these ecoystems are affected by humans. Glaciology is the study of the cryosphere, including glaciers and coverage of the Earth by ice and snow. Concerns of glaciology include access to glacial freshwater, mitigation of glacial hazards, obtaining resources that exist beneath frozen land, and addressing the effects of climate change on the cryosphere. == Ecology == Ecology is the study of the biosphere. This includes the study of nature and of how living things interact with the Earth and one another and the consequences of that. It considers how living things use resources such as oxygen, water, and nutrients from the Earth to sustain themselves. It also considers how humans and other living creatures cause changes to nature. == Physical geography == Physical geography is the study of Earth's systems and how they interact with one another as part of a single self-contained system. It incorporates astronomy, mathematical geography, meteorology, climatology, geology, geomorphology, biology, biogeography, pedology, and soils geography. Physical geography is distinct from human geography, which studies the human populations on Earth, though it does include human effects on the environment. == Methodology == Methodologies vary depending on the nature of the subjects being studied. Studies typically fall into one of three categories: observational, experimental, or theoretical. Earth scientists often conduct sophisticated computer analysis or visit an interesting location to study earth phenomena (e.g. Antarctica or hot spot island chains). A foundational idea in Earth science is the notion of uniformitarianism, which states that "ancient geologic features are interpreted by understanding active processes that are readily observed." In other words, any geologic processes at work in the present have operated in the same ways throughout geologic time. This enables those who study Earth history to apply knowledge of how the Earth's processes operate in the present to gain insight into how the planet has evolved and changed throughout long history. == Earth's spheres == In Earth science, it is common to conceptualize the Earth's surface as consisting of several distinct layers, often referred to as spheres: the lithosphere, the hydrosphere, the atmosphere, and the biosphere, this concept of spheres is a useful tool for understanding the Earth's surface and its various processes these correspond to rocks, water, air and life. Also included by some are the cryosphere (corresponding to ice) as a distinct portion of the hydrosphere and the pedosphere (corresponding to soil) as an active and intermixed sphere. The following fields of science are generally categorized within the Earth sciences: Geology describes the rocky parts of the Earth's crust (or lithosphere) and its historic development. Major subdisciplines are mineralogy and petrology, geomorphology, paleontology, stratigraphy, structural geology, engineering geology, and sedimentology. Physical geography focuses on geography as an Earth science. Physical geography is the study of Earth's seasons, climate, atmosphere, soil, streams, landforms, and oceans. Physical geography can be divided into several branches or related fields, as follows: geomorphology, biogeography, environmental geography, palaeogeography, climatology, meteorology, coastal geography, hydrology, ecology, glaciology. Geophysics and geodesy investigate the shape of the Earth, its reaction to forces and its magnetic and gravity fields. Geophysicists explore the Earth's core and mantle as well as the tectonic and seismic activity of the lithosphere. Geophysics is commonly used to supplement the work of geologists in developing a comprehensive understanding of crustal geology, particularly in mineral and petroleum exploration. Seismologists use geophysics to understand plate tectonic movement, as well as predict seismic activity. Geochemistry studies the processes that control the abundance, composition, and distribution of chemical compounds and isotopes in geologic environments. Geochemists use the tools and principles of chemistry to study the Earth's composition, structure, processes, and other physical aspects. Major subdisciplines are aqueous geochemistry, cosmochemistry, isotope geochemistry and biogeochemistry. Soil science covers the outermost layer of the Earth's crust that is subject to soil formation processes (or pedosphere). Major subdivisions in this field of study include edaphology and pedology. Ecology covers the interactions between organisms and their environment. This field of study differentiates the study of Earth from other planets in the Solar System, Earth being the only planet teeming with life. Hydrology, oceanography and limnology are studies which focus on the movement, distribution, and quality of the water and involve all the components of the hydrologic cycle on the Earth and its atmosphere (or hydrosphere). "Sub-disciplines of hydrology include hydrometeorology, surface water hydrology, hydrogeology, watershed science, forest hydrology, and water chemistry." Glaciology covers the icy parts of the Earth (or cryosphere). Atmospheric sciences cover the gaseous parts of the Earth (or atmosphere) between the surface and the exosphere (about 1000 km). Major subdisciplines include meteorology, climatology, atmospheric chemistry, and atmospheric physics. === Earth science breakup === == See also == == References == === Sources === == Further reading == == External links == Earth Science Picture of the Day, a service of Universities Space Research Association, sponsored by NASA Goddard Space Flight Center. Geoethics in Planetary and Space Exploration. Geology Buzz: Earth Science Archived 2021-11-04 at the Wayback Machine
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Military science is the study of military processes, institutions, and behavior, along with the study of warfare, and the theory and application of organized coercive force. It is mainly focused on theory, method, and practice of producing military capability in a manner consistent with national defense policy. Military science serves to identify the strategic, political, economic, psychological, social, operational, technological, and tactical elements necessary to sustain relative advantage of military force; and to increase the likelihood and favorable outcomes of victory in peace or during a war. Military scientists include theorists, researchers, experimental scientists, applied scientists, designers, engineers, test technicians, and other military personnel. Military personnel obtain weapons, equipment, and training to achieve specific strategic goals. Military science is also used to establish enemy capability as part of technical intelligence. In military history, military science had been used during the period of Industrial Revolution as a general term to refer to all matters of military theory and technology application as a single academic discipline, including that of the deployment and employment of troops in peacetime or in battle. In military education, military science is often the name of the department in the education institution that administers officer candidate education. However, this education usually focuses on the officer leadership training and basic information about employment of military theories, concepts, methods and systems, and graduates are not military scientists on completion of studies, but rather junior military officers. == History == Even until the Second World War, military science was written in English starting with capital letters, and was thought of as an academic discipline alongside physics, philosophy and the medical sciences. In part this was due to the general mystique that accompanied education in a world where, as late as the 1880s, 75% of the European population was illiterate. The ability by the officers to make complex calculations required for the equally complex "evolutions" of the troop movements in linear warfare that increasingly dominated the Renaissance and later history, and the introduction of the gunpowder weapons into the equation of warfare only added to the veritable arcana of building fortifications as it seemed to the average individual. Until the early 19th century, one observer, a British veteran of the Napoleonic Wars, Major John Mitchell, thought that it seemed nothing much had changed from the application of force on a battlefield since the days of the Greeks. He suggested that this was primarily so because as Clausewitz suggested, "unlike in any other science or art, in war the object reacts". Until this time, and even after the Franco-Prussian War, military science continued to be divided between the formal thinking of officers brought up in the "shadow" of the Napoleonic Wars and younger officers like Ardant du Picq who tended to view fighting performance as rooted in the individual's and group psychology and suggested detailed analysis of this. This set in motion the eventual fascination of the military organisations with application of quantitative and qualitative research to their theories of combat; the attempt to translate military thinking as philosophic concepts into concrete methods of combat. Military implements, the supply of an army, its organization, tactics, and discipline, have constituted the elements of military science in all ages; but improvement in weapons and accoutrements appears to lead and control all the rest. The breakthrough of sorts made by Clausewitz in suggesting eight principles on which such methods can be based, in Europe, for the first time presented an opportunity to largely remove the element of chance and error from command decision making process. At this time emphasis was made on the topography (including trigonometry), military art (military science), military history, organisation of the army in the field, artillery and the science of projectiles, field fortifications and permanent fortifications, military legislation, military administration and manoeuvres. The military science on which the model of German combat operations was built for the First World War remained largely unaltered from the Napoleonic model, but took into the consideration the vast improvements in the firepower and the ability to conduct "great battles of annihilation" through rapid concentration of force, strategic mobility, and the maintenance of the strategic offensive better known as the Cult of the offensive. The key to this, and other modes of thinking about war, remained analysis of military history and attempts to derive tangible lessons that could be replicated again with equal success on another battlefield as a sort of bloody laboratory of military science. Few were bloodier than the fields of the Western Front between 1914 and 1918. The person who probably understood Clausewitz better than most, Marshal Foch, initially participated in events that nearly destroyed the French Army. It is not, however, true to say that military theorists and commanders were suffering from some collective case of stupidity. Their analysis of military history convinced them that decisive and aggressive strategic offensive was the only doctrine of victory, and feared that overemphasis of firepower, and the resultant dependence on entrenchment would make this all but impossible, and leading to the battlefield stagnant in advantages of the defensive position, destroying troop morale and willingness to fight. Because only the offensive could bring victory, lack of it, and not the firepower, was blamed for the defeat of the Imperial Russian Army in the Russo-Japanese War. Foch thought that "In strategy as well as in tactics one attacks". In many ways military science was born as a result of the experiences of the Great War. "Military implements" had changed armies beyond recognition with cavalry to virtually disappear in the next 20 years. The "supply of an army" would become a science of logistics in the wake of massive armies, operations and troops that could fire ammunition faster than it could be produced, for the first time using vehicles that used the combustion engine, a watershed of change. Military "organisation" would no longer be that of the linear warfare, but assault teams, and battalions that were becoming multi-skilled with the introduction of machine guns and mortars and, for the first time, forcing military commanders to think not only in terms of rank and file, but force structure. Tactics changed, too, with infantry for the first time segregated from the horse-mounted troops, and required to cooperate with tanks, aircraft and new artillery tactics. Perception of military discipline, too, had changed. Morale, despite strict disciplinarian attitudes, had cracked in all armies during the war, but the best-performing troops were found to be those where emphasis on discipline had been replaced with display of personal initiative and group cohesiveness such as that found in the Australian Corps during the Hundred Days Offensive. The military sciences' analysis of military history that had failed European commanders was about to give way to a new military science, less conspicuous in appearance, but more aligned to the processes of science of testing and experimentation, the scientific method, and forever "wed" to the idea of the superiority of technology on the battlefield. Currently military science still means many things to different organisations. In the United Kingdom and much of the European Union the approach is to relate it closely to the civilian application and understanding. For example, in Belgium's Royal Military Academy, military science remains an academic discipline, and is studied alongside social sciences, including such subjects as humanitarian law. The United States Department of Defense defines military science in terms of specific systems and operational requirements, and include among other areas civil defense and force structure. == Employment of military skills == In the first instance military science is concerned with who will participate in military operations, and what sets of skills and knowledge they will require to do so effectively and somewhat ingeniously. === Military organization === Develops optimal methods for the administration and organization of military units, as well as the military as a whole. In addition, this area studies other associated aspects as mobilization/demobilization, and military government for areas recently conquered (or liberated) from enemy control. === Force structuring === Force structuring is the method by which personnel and the weapons and equipment they use are organized and trained for military operations, including combat. Development of force structure in any country is based on strategic, operational, and tactical needs of the national defense policy, the identified threats to the country, and the technological capabilities of the threats and the armed forces. Force structure development is guided by doctrinal considerations of strategic, operational and tactical deployment and employment of formations and units to territories, areas and zones where they are expected to perform their missions and tasks. Force structuring applies to all armed services, but not to their supporting organisations such as those used for defense science research activities. In the United States force structure is guided by the table of organization and equipment (TOE or TO&E). The TOE is a document published by the U.S. Department of Defense which prescribes the organization, manning, and equipage of units from divisional size and down, but also including the headquarters of corps and armies. Force structuring also provides information on the mission and capabilities of specific units, as well as the unit's current status in terms of posture and readiness. A general TOE is applicable to a type of unit (for instance, infantry) rather than a specific unit (the 3rd Infantry Division). In this way, all units of the same branch (such as infantry) follow the same structural guidelines which allows for more efficient financing, training, and employment of like units operationally. === Military education and training === Studies the methodology and practices involved in training soldiers, NCOs (non-commissioned officers, i.e. sergeants and corporals), and officers. It also extends this to training small and large units, both individually and in concert with one another for both the regular and reserve organizations. Military training, especially for officers, also concerns itself with general education and political indoctrination of the armed forces. == Military concepts and methods == Much of capability development depends on the concepts which guide use of the armed forces and their weapons and equipment, and the methods employed in any given theatre of war or combat environment. According to Dr. Kajal Nayan: Artificial Intelligence Cyber War Era Currently, along with the cyber war era, with the help of new technology in the field of military science, the infancy of the "Artificial Intelligence Military Science era" cyber war experiments have started in which with the help of AI, this era can be made even more effective. Military activity has been a constant process over thousands of years, and the essential tactics, strategy, and goals of military operations have been unchanging throughout history. As an example, one notable maneuver is the double envelopment, considered to be the consummate military maneuver, notably executed by Hannibal at the Battle of Cannae in 216 BCE, and later by Khalid ibn al-Walid at the Battle of Walaja in 633 CE. Via the study of history, the military seeks to avoid past mistakes, and improve upon its current performance by instilling an ability in commanders to perceive historical parallels during battle, so as to capitalize on the lessons learned. The main areas military history includes are the history of wars, battles, and combats, history of the military art, and history of each specific military service. === Military strategy and doctrines === Military strategy is in many ways the centerpiece of military science. It studies the specifics of planning for, and engaging in combat, and attempts to reduce the many factors to a set of principles that govern all interactions of the field of battle. In Europe these principles were first defined by Clausewitz in his Principles of War. As such, it directs the planning and execution of battles, operations, and wars as a whole. Two major systems prevail on the planet today. Broadly speaking, these may be described as the "Western" system, and the "Russian" system. Each system reflects and supports strengths and weakness in the underlying society. Modern Western military art is composed primarily of an amalgam of French, German, British, and American systems. The Russian system borrows from these systems as well, either through study, or personal observation in the form of invasion (Napoleon's War of 1812, and The Great Patriotic War), and form a unique product suited for the conditions practitioners of this system will encounter. The system that is produced by the analysis provided by military art is known as doctrine. Western military doctrine relies heavily on technology, the use of a well-trained and empowered NCO cadre, and superior information processing and dissemination to provide a level of battlefield awareness that opponents cannot match. Its advantages are extreme flexibility, extreme lethality, and a focus on removing an opponent's C3I (command, communications, control, and intelligence) to paralyze and incapacitate rather than destroying their combat power directly (hopefully saving lives in the process). Its drawbacks are high expense, a reliance on difficult-to-replace personnel, an enormous logistic train, and a difficulty in operating without high technology assets if depleted or destroyed. Soviet military doctrine (and its descendants, in CIS countries) relies heavily on masses of machinery and troops, a highly educated (albeit very small) officer corps, and pre-planned missions. Its advantages are that it does not require well educated troops, does not require a large logistic train, is under tight central control, and does not rely on a sophisticated C3I system after the initiation of a course of action. Its disadvantages are inflexibility, a reliance on the shock effect of mass (with a resulting high cost in lives and material), and overall inability to exploit unexpected success or respond to unexpected loss. Chinese military doctrine is currently in a state of flux as the People's Liberation Army is evaluating military trends of relevance to China. Chinese military doctrine is influenced by a number of sources including an indigenous classical military tradition characterized by strategists such as Sun Tzu, Western and Soviet influences, as well as indigenous modern strategists such as Mao Zedong. One distinctive characteristic of Chinese military science is that it places emphasis on the relationship between the military and society as well as viewing military force as merely one part of an overarching grand strategy. Each system trains its officer corps in its philosophy regarding military art. The differences in content and emphasis are illustrative. The United States Army principles of war are defined in the U.S. Army Field Manual FM 100–5. The Canadian Forces principles of war/military science are defined by Land Forces Doctrine and Training System (LFDTS) to focus on principles of command, principles of war, operational art and campaign planning, and scientific principles. Russian Federation armed forces derive their principles of war predominantly from those developed during the existence of the Soviet Union. These, although based significantly on the Second World War experience in conventional war fighting, have been substantially modified since the introduction of the nuclear arms into strategic considerations. The Soviet–Afghan War and the First and Second Chechen Wars further modified the principles that Soviet theorists had divided into the operational art and tactics. The very scientific approach to military science thinking in the Soviet union had been perceived as overly rigid at the tactical level, and had affected the training in the Russian Federation's much reduced forces to instil greater professionalism and initiative in the forces. The military principles of war of the People's Liberation Army were loosely based on those of the Soviet Union until the 1980s when a significant shift begun to be seen in a more regionally-aware, and geographically-specific strategic, operational and tactical thinking in all services. The PLA is currently influenced by three doctrinal schools which both conflict and complement each other: the People's war, the Regional war, and the Revolution in military affairs that led to substantial increase in the defense spending and rate of technological modernisation of the forces. The differences in the specifics of military art notwithstanding, military science strives to provide an integrated picture of the chaos of battle, and illuminate basic insights that apply to all combatants, not just those who agree with your formulation of the principles. === Military geography === Military geography encompasses much more than simple protestations to take the high ground. Military geography studies the obvious, the geography of theatres of war, but also the additional characteristics of politics, economics, and other natural features of locations of likely conflict (the political "landscape", for example). As an example, the Soviet–Afghan War was predicated on the ability of the Soviet Union to not only successfully invade Afghanistan, but also to militarily and politically flank the Islamic Republic of Iran simultaneously. == Military systems == How effectively and efficiently militaries accomplish their operations, missions and tasks is closely related not only to the methods they use, but the equipment and weapons they use. === Military intelligence === Military intelligence supports the combat commanders' decision making process by providing intelligence analysis of available data from a wide range of sources. To provide that informed analysis the commanders information requirements are identified and input to a process of gathering, analysis, protection, and dissemination of information about the operational environment, hostile, friendly and neutral forces and the civilian population in an area of combat operations, and broader area of interest. Intelligence activities are conducted at all levels from tactical to strategic, in peacetime, the period of transition to war, and during the war. Most militaries maintain a military intelligence capability to provide analytical and information collection personnel in both specialist units and from other arms and services. Personnel selected for intelligence duties, whether specialist intelligence officers and enlisted soldiers or non-specialist assigned to intelligence may be selected for their analytical abilities and intelligence before receiving formal training. Military intelligence serves to identify the threat, and provide information on understanding best methods and weapons to use in deterring or defeating it. === Military logistics === The art and science of planning and carrying out the movement and maintenance of military forces. In its most comprehensive sense, it is those aspects or military operations that deal with the design, development, acquisition, storage, distribution, maintenance, evacuation, and disposition of material; the movement, evacuation, and hospitalization of personnel; the acquisition or construction, maintenance, operation, and disposition of facilities; and the acquisition or furnishing of services. === Military technology and equipment === Military technology is not just the study of various technologies and applicable physical sciences used to increase military power. It may also extend to the study of production methods of military equipment, and ways to improve performance and reduce material and/or technological requirements for its production. An example is the effort expended by Nazi Germany to produce artificial rubbers and fuels to reduce or eliminate their dependence on imported POL (petroleum, oil, and lubricants) and rubber supplies. Military technology is unique only in its application, not in its use of basic scientific and technological achievements. Because of the uniqueness of use, military technological studies strive to incorporate evolutionary, as well as the rare revolutionary technologies, into their proper place of military application. == Military and society == This speciality examines the ways that military and society interact and shape each other. The dynamic intersection where military and society meet is influenced by trends in society and the security environment. This field of study can be linked to works by Clausewitz ("War is the continuation of politics by other means") and Sun Tzu ("If not in the interest of the state, do not act" ). The contemporary multi and interdisciplinary field traces its origin to World War II and works by sociologists and political scientists. This field of study includes "all aspects of relations between armed forces, as a political, social and economic institution, and the society, state or political ethnic movement of which they are a part". Topics often included within the purview of military and society include: veterans, women in the military, military families, enlistment and retention, reserve forces, military and religion, military privatization, civil-military relations, civil-military cooperation, military and popular culture, military and the media, military and disaster assistance, military and the environment and the blurring of military and police functions. === Recruitment and retention === In an all-volunteer military, the armed forces relies on market forces and careful recruiting to fill its ranks. It is thus, very important to understand factors that motivate enlistment and reenlistment. Service members must have the mental and physical ability to meet the challenges of military service and adapt to the military's values and culture. Studies show that enlistment motivation generally incorporates both self-interest (pay) and non-market values like adventure, patriotism, and comradeship. === Veterans === The study of veterans or members of the military who leave and return to the society is one of the most important subfields of the military and society field of study. Veterans and their issues represent a microcosm of the field. Military recruits represent inputs that flow from the community into the armed forces, veterans are outputs that leave the military and reenter society changed by their time as soldiers, sailors, marines and airmen. Both society and veteran face multiple layers of adaptation and adjustment upon their reentry. The definition of veteran is surprisingly fluid across countries. In the US, veteran's status is established after a service member has completed a minimum period of service. Australia requires deployment to a combat zone. In the UK "Everyone who has performed military service for at least one day and drawn a day's pay is termed a veteran." The study of veterans focuses much attention on their, sometimes, uneasy transition back to civilian society. "Veterans must navigate a complex cultural transition when moving between environments," and they can expect positive and negative transition outcomes. Finding a good job and reestablishing a fulfilling family life is high on their resettlement agenda. Military life is often violent and dangerous. The trauma of combat often results in post-traumatic stress disorder as well as painful physical health challenges which often lead to homelessness, suicide, substance, and excessive alcohol use, and family dysfunction. Society recognizes its responsibilities to veterans by offering programs and policies designed to redress these problems. Veterans also exert an influence on society often through the political process. For example, how do veterans vote and establish party affiliation? During the 2004 presidential election veterans were basically bipartisan. Veterans who fought in Croatia's war of independence voted for the nationalist parties in greater numbers. === Reserve forces === Reserve forces are service members who serve the armed forces on a part-time basis. These men and women constitute a "reserve" force that countries rely on for their defense, disaster support, and some day-to-day operations etc. In the United States an active reservist spends a weekend a month and two weeks a year in training. The size of a county's reserve force often depends on the type of recruitment method. Nations with a volunteer force tend to have a lower reserve percentage. Recently the role of the reserves has changed. In many countries it has gone from a strategic force, largely static, to an operational force, largely dynamic. After WWII, relatively large standing forces took care of most operational needs. Reserves were held back strategically and deployed in times of emergency for example during the Cuban missile crisis. Subsequently, the strategic and budget situation changed and as a result the active duty military began to rely on reserve force, particularly for combat support and combat service support. Further large-scale military operation, routinely mobilize and deploy reservists Lomsky-Feder et al (2008p. 594) introduced the metaphor of reserve forces as transmigrants who live "betwixt and between the civilian and military worlds". This metaphor captures "their structural duality" and suggests dynamic nature of reservist experience as they navigate commitments to their often conflicting civilian and military worlds. Given their greater likelihood of lengthy deployment, reservists face many of the same stresses as active duty but often with fewer support services. == University studies == Universities (or colleges) around the world also offer a degree(s) in military science: Belgium: Royal Military Academy (Belgium)- BA Social and Military Science; MA Social and Military Science Israel: Tel Aviv University – MA in Security. Bar-Ilan University – MA in Military, Security and Intelligence. Finland: National Defence University – Bachelor, Master, and PhD in Military science France: Sciences Po, Paris School of International Affairs - Master in International Security. New Zealand: Massey University, Centre for Defence and Security Studies – BA in Defence Studies. Victoria University of Wellington – Centre for Strategic Studies – Master of Strategic Studies (MSS). Slovenia: University of Ljubljana, Faculty of Social Studies – BA, MA and PhD in Defence studies; PhD in Military-Social Sciences United Kingdom: King's College London – MA in International Security and Strategy; MA, MPhil/PhD in Defence Studies University of Hull – MA in Strategy and International Security University of St Andrews - MLitt in Strategic Studies Sri Lanka Sri Lanka Military Academy - (Bachelor and Master's degree in Military Studies) Military training school Diyatalawa, Sri Lanka South Africa South African Military Academy / University of Stellenbosch - Bachelor of Military Science (BMil), Master of Military Science (MMil), MPhil in Security Management United States: United States Air Force Academy – Major in Military and Strategic Studies; Minor in Nuclear Weapons and Strategy United States Military Academy – Major in Defense and Strategic Studies Hawaii Pacific University – Major in Diplomacy and Military Studies Missouri State University – Minor in Military Studies == International military sciences or studies associations == There are many international associations with the core purpose of bringing scholars in the field of Military Science together. Some are inter-disciplinary and have a broad scope, whilst others are confined and specialized focusing on more specific disciplines or subjects. Some are integrated in larger scientific communities like the International Sociological Association (ISA) and the American Psychological Association (APA) where others have grown out of military institutions or individuals who have had a particular interest in areas of military science and are military, defense or armed forces oriented. Some of these associations are: American Psychological Association; Division 19: Society for Military Psychology (APA-Div19) European Research Group on Military and Society (ERGOMAS) Inter-University Seminar on Armed Forces and Society (IUS) International Congress on Soldiers Physical Performance (ICSPP) International Military Testing Association (IMTA) International Society of Military Sciences (ISMS) International Sociological Association; RC01 Armed Forces and Conflict Resolution International Association for Military Pedagogy == Military studies journals == The following are notable journals in the field: == See also == Military doctrine – Codified expression of how fighters conduct campaigns, operations, battles and engagements Military theory – Study of the theories of war and warfare War – Intense armed conflict List of basic military science and technology topics – Overview of and topical guide to military science and technologyPages displaying short descriptions of redirect targets List of military inventions List of military writers Philosophy of war – Theory of causes and ethics of armed conflict == References == Notes Bibliography == External links == Military Technology US Military/Government Texts The Logic of Warfighting Experiments by Kass (CCRP, 2006) Complexity, Networking, and Effects Based Approaches to Operations by Smith (CCRP, 2006) Understanding Command and Control by Alberts and Hayes (CCRP, 2006) The Agile Organization by Atkinson and Moffat (CCRP, 2005) Power to the Edge by Alberts and Hayes (CCRP, 2003) Network Centric Warfare by Alberts et al. (CCRP, 1999)
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https://en.wikipedia.org/wiki/Military_science
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The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the United States's civil space program, aeronautics research and space research. Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the US space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program, and oversees the development of the Orion spacecraft and the Space Launch System for the lunar Artemis program. NASA's science division is focused on better understanding Earth through the Earth Observing System; advancing heliophysics through the efforts of the Science Mission Directorate's Heliophysics Research Program; exploring bodies throughout the Solar System with advanced robotic spacecraft such as New Horizons and planetary rovers such as Perseverance; and researching astrophysics topics, such as the Big Bang, through the James Webb Space Telescope, the four Great Observatories, and associated programs. The Launch Services Program oversees launch operations for its uncrewed launches. == History == === Creation === NASA traces its roots to the National Advisory Committee for Aeronautics (NACA). Despite being the birthplace of aviation, by 1914 the United States recognized that it was far behind Europe in aviation capability. Determined to regain American leadership in aviation, the United States Congress created the Aviation Section of the US Army Signal Corps in 1914 and established NACA in 1915 to foster aeronautical research and development. Over the next forty years, NACA would conduct aeronautical research in support of the US Air Force, US Army, US Navy, and the civil aviation sector. After the end of World War II, NACA became interested in the possibilities of guided missiles and supersonic aircraft, developing and testing the Bell X-1 in a joint program with the US Air Force. NACA's interest in space grew out of its rocketry program at the Pilotless Aircraft Research Division. The Soviet Union's launch of Sputnik 1 ushered in the Space Age and kicked off the Space Race. Despite NACA's early rocketry program, the responsibility for launching the first American satellite fell to the Naval Research Laboratory's Project Vanguard, whose operational issues ensured the Army Ballistic Missile Agency would launch Explorer 1, America's first satellite, on February 1, 1958. The Eisenhower Administration decided to split the United States's military and civil spaceflight programs, which were organized together under the Department of Defense's Advanced Research Projects Agency. NASA was established on July 29, 1958, with the signing of the National Aeronautics and Space Act and it began operations on October 1, 1958. As the US's premier aeronautics agency, NACA formed the core of NASA's new structure by reassigning 8,000 employees and three major research laboratories. NASA also proceeded to absorb the Naval Research Laboratory's Project Vanguard, the Army's Jet Propulsion Laboratory (JPL), and the Army Ballistic Missile Agency under Wernher von Braun. This left NASA firmly as the United States's civil space lead and the Air Force as the military space lead. === First orbital and hypersonic flights === Plans for human spaceflight began in the US Armed Forces prior to NASA's creation. The Air Force's Man in Space Soonest project formed in 1956, coupled with the Army's Project Adam, served as the foundation for Project Mercury. NASA established the Space Task Group to manage the program, which would conduct crewed sub-orbital flights with the Army's Redstone rockets and orbital flights with the Air Force's Atlas launch vehicles. While NASA intended for its first astronauts to be civilians, President Eisenhower directed that they be selected from the military. The Mercury 7 astronauts included three Air Force pilots, three Navy aviators, and one Marine Corps pilot. On May 5, 1961, Alan Shepard became the first American to enter space, performing a suborbital spaceflight in the Freedom 7. This flight occurred less than a month after the Soviet Yuri Gagarin became the first human in space, executing a full orbital spaceflight. NASA's first orbital spaceflight was conducted by John Glenn on February 20, 1962, in the Friendship 7, making three full orbits before reentering. Glenn had to fly parts of his final two orbits manually due to an autopilot malfunction. The sixth and final Mercury mission was flown by Gordon Cooper in May 1963, performing 22 orbits over 34 hours in the Faith 7. The Mercury Program was wildly recognized as a resounding success, achieving its objectives to orbit a human in space, develop tracking and control systems, and identify other issues associated with human spaceflight. While much of NASA's attention turned to space, it did not put aside its aeronautics mission. Early aeronautics research attempted to build upon the X-1's supersonic flight to build an aircraft capable of hypersonic flight. The North American X-15 was a joint NASA–US Air Force program, with the hypersonic test aircraft becoming the first non-dedicated spacecraft to cross from the atmosphere to outer space. The X-15 also served as a testbed for Apollo program technologies, as well as ramjet and scramjet propulsion. === Moon landing === Escalations in the Cold War between the United States and Soviet Union prompted President John F. Kennedy to charge NASA with landing an American on the Moon and returning him safely to Earth by the end of the 1960s and installed James E. Webb as NASA administrator to achieve this goal. On May 25, 1961, President Kennedy openly declared this goal in his "Urgent National Needs" speech to the United States Congress, declaring: I believe this Nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. Kennedy gave his "We choose to go to the Moon" speech the next year, on September 12, 1962 at Rice University, where he addressed the nation hoping to reinforce public support for the Apollo program. Despite attacks on the goal of landing astronauts on the Moon from the former president Dwight Eisenhower and 1964 presidential candidate Barry Goldwater, President Kennedy was able to protect NASA's growing budget, of which 50% went directly to human spaceflight and it was later estimated that, at its height, 5% of Americans worked on some aspect of the Apollo program. Mirroring the Department of Defense's program management concept using redundant systems in building the first intercontinental ballistic missiles, NASA requested the Air Force assign Major General Samuel C. Phillips to the space agency where he would serve as the director of the Apollo program. Development of the Saturn V rocket was led by Wernher von Braun and his team at the Marshall Space Flight Center, derived from the Army Ballistic Missile Agency's original Saturn I. The Apollo spacecraft was designed and built by North American Aviation, while the Apollo Lunar Module was designed and built by Grumman. To develop the spaceflight skills and equipment required for a lunar mission, NASA initiated Project Gemini. Using a modified Air Force Titan II launch vehicle, the Gemini capsule could hold two astronauts for flights of over two weeks. Gemini pioneered the use of fuel cells instead of batteries, and conducted the first American spacewalks and rendezvous operations. The Ranger Program was started in the 1950s as a response to Soviet lunar exploration, however most missions ended in failure. The Lunar Orbiter program had greater success, mapping the surface in preparation for Apollo landings, conducting meteoroid detection, and measuring radiation levels. The Surveyor program conducted uncrewed lunar landings and takeoffs, as well as taking surface and regolith observations. Despite the setback caused by the Apollo 1 fire, which killed three astronauts, the program proceeded. Apollo 8 was the first crewed spacecraft to leave low Earth orbit and the first human spaceflight to reach the Moon. The crew orbited the Moon ten times on December 24 and 25, 1968, and then traveled safely back to Earth. The three Apollo 8 astronauts—Frank Borman, James Lovell, and William Anders—were the first humans to see the Earth as a globe in space, the first to witness an Earthrise, and the first to see and manually photograph the far side of the Moon. The first lunar landing was conducted by Apollo 11. Commanded by Neil Armstrong with astronauts Buzz Aldrin and Michael Collins, Apollo 11 was one of the most significant missions in NASA's history, marking the end of the Space Race when the Soviet Union gave up its lunar ambitions. As the first human to step on the surface of the Moon, Neil Armstrong uttered the now famous words: That's one small step for man, one giant leap for mankind. NASA would conduct six total lunar landings as part of the Apollo program, with Apollo 17 concluding the program in 1972. ==== End of Apollo ==== Wernher von Braun had advocated for NASA to develop a space station since the agency was created. In 1973, following the end of the Apollo lunar missions, NASA launched its first space station, Skylab, on the final launch of the Saturn V. Skylab reused a significant amount of Apollo and Saturn hardware, with a repurposed Saturn V third stage serving as the primary module for the space station. Damage to Skylab during its launch required spacewalks to be performed by the first crew to make it habitable and operational. Skylab hosted nine missions and was decommissioned in 1974 and deorbited in 1979, two years prior to the first launch of the Space Shuttle and any possibility of boosting its orbit. In 1975, the Apollo–Soyuz mission was the first ever international spaceflight and a major diplomatic accomplishment between the Cold War rivals, which also marked the last flight of the Apollo capsule. Flown in 1975, a US Apollo spacecraft docked with a Soviet Soyuz capsule. === Interplanetary exploration and space science === During the 1960s, NASA started its space science and interplanetary probe program. The Mariner program was its flagship program, launching probes to Venus, Mars, and Mercury in the 1960s. The Jet Propulsion Laboratory was the lead NASA center for robotic interplanetary exploration, making significant discoveries about the inner planets. Despite these successes, Congress was unwilling to fund further interplanetary missions and NASA Administrator James Webb suspended all future interplanetary probes to focus resources on the Apollo program. Following the conclusion of the Apollo program, NASA resumed launching interplanetary probes and expanded its space science program. The first planet tagged for exploration was Venus, sharing many similar characteristics to Earth. First visited by American Mariner 2 spacecraft, Venus was observed to be a hot and inhospitable planet. Follow-on missions included the Pioneer Venus project in the 1970s and Magellan, which performed radar mapping of Venus' surface in the 1980s and 1990s. Future missions were flybys of Venus, on their way to other destinations in the Solar System. Mars has long been a planet of intense fascination for NASA, being suspected of potentially having harbored life. Mariner 5 was the first NASA spacecraft to flyby Mars, followed by Mariner 6 and Mariner 7. Mariner 9 was the first orbital mission to Mars. Launched in 1975, Viking program consisted of two landings on Mars in 1976. Follow-on missions would not be launched until 1996, with the Mars Global Surveyor orbiter and Mars Pathfinder, deploying the first Mars rover, Sojourner. During the early 2000s, the 2001 Mars Odyssey orbiter reached the planet and in 2004 the Sprit and Opportunity rovers landed on the Red Planet. This was followed in 2005 by the Mars Reconnaissance Orbiter and 2007 Phoenix Mars lander. The 2012 landing of Curiosity discovered that the radiation levels on Mars were equal to those on the International Space Station, greatly increasing the possibility of Human exploration, and observed the key chemical ingredients for life to occur. In 2013, the Mars Atmosphere and Volatile Evolution (MAVEN) mission observed the Martian upper atmosphere and space environment and in 2018, the Interior exploration using Seismic Investigations Geodesy, and Heat Transport (InSight) studied the Martian interior. The 2021 Perseverance rover carried the first extraplanetary aircraft, a helicopter named Ingenuity. NASA also launched missions to Mercury in 2004, with the MESSENGER probe demonstrating as the first use of a solar sail. NASA also launched probes to the outer Solar System starting in the 1960s. Pioneer 10 was the first probe to the outer planets, flying by Jupiter, while Pioneer 11 provided the first close up view of the planet. Both probes became the first objects to leave the Solar System. The Voyager program launched in 1977, conducting flybys of Jupiter and Saturn, Neptune, and Uranus on a trajectory to leave the Solar System. The Galileo spacecraft, deployed from the Space Shuttle flight STS-34, was the first spacecraft to orbit Jupiter, discovering evidence of subsurface oceans on the Europa and observed that the moon may hold ice or liquid water. A joint NASA-European Space Agency-Italian Space Agency mission, Cassini–Huygens, was sent to Saturn's moon Titan, which, along with Mars and Europa, are the only celestial bodies in the Solar System suspected of being capable of harboring life. Cassini discovered three new moons of Saturn and the Huygens probe entered Titan's atmosphere. The mission discovered evidence of liquid hydrocarbon lakes on Titan and subsurface water oceans on the moon of Enceladus, which could harbor life. Finally launched in 2006, the New Horizons mission was the first spacecraft to visit Pluto and the Kuiper Belt. Beyond interplanetary probes, NASA has launched many space telescopes. Launched in the 1960s, the Orbiting Astronomical Observatory were NASA's first orbital telescopes, providing ultraviolet, gamma-ray, x-ray, and infrared observations. NASA launched the Orbiting Geophysical Observatory in the 1960s and 1970s to look down at Earth and observe its interactions with the Sun. The Uhuru satellite was the first dedicated x-ray telescope, mapping 85% of the sky and discovering a large number of black holes. Launched in the 1990s and early 2000s, the Great Observatories program are among NASA's most powerful telescopes. The Hubble Space Telescope was launched in 1990 on STS-31 from the Discovery and could view galaxies 15 billion light years away. A major defect in the telescope's mirror could have crippled the program, had NASA not used computer enhancement to compensate for the imperfection and launched five Space Shuttle servicing flights to replace the damaged components. The Compton Gamma Ray Observatory was launched from the Atlantis on STS-37 in 1991, discovering a possible source of antimatter at the center of the Milky Way and observing that the majority of gamma-ray bursts occur outside of the Milky Way galaxy. The Chandra X-ray Observatory was launched from the Columbia on STS-93 in 1999, observing black holes, quasars, supernova, and dark matter. It provided critical observations on the Sagittarius A* black hole at the center of the Milky Way galaxy and the separation of dark and regular matter during galactic collisions. Finally, the Spitzer Space Telescope is an infrared telescope launched in 2003 from a Delta II rocket. It is in a trailing orbit around the Sun, following the Earth and discovered the existence of brown dwarf stars. Other telescopes, such as the Cosmic Background Explorer and the Wilkinson Microwave Anisotropy Probe, provided evidence to support the Big Bang. The James Webb Space Telescope, named after the NASA administrator who lead the Apollo program, is an infrared observatory launched in 2021. The James Webb Space Telescope is a direct successor to the Hubble Space Telescope, intended to observe the formation of the first galaxies. Other space telescopes include the Kepler space telescope, launched in 2009 to identify planets orbiting extrasolar stars that may be Terran and possibly harbor life. The first exoplanet that the Kepler space telescope confirmed was Kepler-22b, orbiting within the habitable zone of its star. NASA also launched a number of different satellites to study Earth, such as Television Infrared Observation Satellite (TIROS) in 1960, which was the first weather satellite. NASA and the United States Weather Bureau cooperated on future TIROS and the second generation Nimbus program of weather satellites. It also worked with the Environmental Science Services Administration on a series of weather satellites and the agency launched its experimental Applications Technology Satellites into geosynchronous orbit. NASA's first dedicated Earth observation satellite, Landsat, was launched in 1972. This led to NASA and the National Oceanic and Atmospheric Administration jointly developing the Geostationary Operational Environmental Satellite and discovering Ozone depletion. === Space Shuttle === NASA had been pursuing spaceplane development since the 1960s, blending the administration's dual aeronautics and space missions. NASA viewed a spaceplane as part of a larger program, providing routine and economical logistical support to a space station in Earth orbit that would be used as a hub for lunar and Mars missions. A reusable launch vehicle would then have ended the need for expensive and expendable boosters like the Saturn V. In 1969, NASA designated the Johnson Space Center as the lead center for the design, development, and manufacturing of the Space Shuttle orbiter, while the Marshall Space Flight Center would lead the development of the launch system. NASA's series of lifting body aircraft, culminating in the joint NASA-US Air Force Martin Marietta X-24, directly informed the development of the Space Shuttle and future hypersonic flight aircraft. Official development of the Space Shuttle began in 1972, with Rockwell International contracted to design the orbiter and engines, Martin Marietta for the external fuel tank, and Morton Thiokol for the solid rocket boosters. NASA acquired six orbiters: the Enterprise, Columbia, Challenger, Discovery, Atlantis, and Endeavour The Space Shuttle program also allowed NASA to make major changes to its Astronaut Corps. While almost all previous astronauts were Air Force or Naval test pilots, the Space Shuttle allowed NASA to begin recruiting more non-military scientific and technical experts. A prime example is Sally Ride, who became the first American woman to fly in space on STS-7. This new astronaut selection process also allowed NASA to accept exchange astronauts from US allies and partners for the first time. The first Space Shuttle flight occurred in 1981, when the Columbia launched on the STS-1 mission, designed to serve as a flight test for the new spaceplane. NASA intended for the Space Shuttle to replace expendable launch systems like the Air Force's Atlas, Delta, and Titan and the European Space Agency's Ariane. The Space Shuttle's Spacelab payload, developed by the European Space Agency, increased the scientific capabilities of shuttle missions over anything NASA was able to previously accomplish. NASA launched its first commercial satellites on the STS-5 mission and in 1984, the STS-41-C mission conducted the world's first on-orbit satellite servicing mission when the Challenger captured and repaired the malfunctioning Solar Maximum Mission satellite. It also had the capability to return malfunctioning satellite to Earth, like it did with the Palapa B2 and Westar 6 satellites. Once returned to Earth, the satellites were repaired and relaunched. Despite ushering in a new era of spaceflight, where NASA was contracting launch services to commercial companies, the Space Shuttle was criticized for not being as reusable and cost-effective as advertised. In 1986, Challenger disaster on the STS-51L mission resulted in the loss of the spacecraft and all seven astronauts on launch, grounding the entire space shuttle fleet for 36 months and forced the 44 commercial companies that contracted with NASA to deploy their satellites to return to expendable launch vehicles. When the Space Shuttle returned to flight with the STS-26 mission, it had undergone significant modifications to improve its reliability and safety. Following the collapse of the Soviet Union, the Russian Federation and United States initiated the Shuttle-Mir program. The first Russian cosmonaut flew on the STS-60 mission in 1994 and the Discovery rendezvoused, but did not dock with, the Russian Mir in the STS-63 mission. This was followed by Atlantis' STS-71 mission where it accomplished the initial intended mission for the Space Shuttle, docking with a space station and transferring supplies and personnel. The Shuttle-Mir program would continue until 1998, when a series of orbital accidents on the space station spelled an end to the program. In 2003, a second space shuttle was destroyed when the Columbia was destroyed upon reentry during the STS-107 mission, resulting in the loss of the spacecraft and all seven astronauts. This accident marked the beginning of the retiring of the Space Shuttle program, with President George W. Bush directing that upon the completion of the International Space Station, the space shuttle be retired. In 2006, the Space Shuttle returned to flight, conducting several mission to service the Hubble Space Telescope, but was retired following the STS-135 resupply mission to the International Space Station in 2011. === Space stations === NASA never gave up on the idea of a space station after Skylab's reentry in 1979. The agency began lobbying politicians to support building a larger space station as soon as the Space Shuttle began flying, selling it as an orbital laboratory, repair station, and a jumping off point for lunar and Mars missions. NASA found a strong advocate in President Ronald Reagan, who declared in a 1984 speech: America has always been greatest when we dared to be great. We can reach for greatness again. We can follow our dreams to distant stars, living and working in space for peaceful, economic, and scientific gain. Tonight I am directing NASA to develop a permanently manned space station and to do it within a decade. In 1985, NASA proposed the Space Station Freedom, which both the agency and President Reagan intended to be an international program. While this would add legitimacy to the program, there were concerns within NASA that the international component would dilute its authority within the project, having never been willing to work with domestic or international partners as true equals. There was also a concern with sharing sensitive space technologies with the Europeans, which had the potential to dilute America's technical lead. Ultimately, an international agreement to develop the Space Station Freedom program would be signed with thirteen countries in 1985, including the European Space Agency member states, Canada, and Japan. Despite its status as the first international space program, the Space Station Freedom was controversial, with much of the debate centering on cost. Several redesigns to reduce cost were conducted in the early 1990s, stripping away much of its functions. Despite calls for Congress to terminate the program, it continued, in large part because by 1992 it had created 75,000 jobs across 39 states. By 1993, President Bill Clinton attempted to significantly reduce NASA's budget and directed costs be significantly reduced, aerospace industry jobs were not lost, and the Russians be included. In 1993, the Clinton Administration announced that the Space Station Freedom would become the International Space Station in an agreement with the Russian Federation. This allowed the Russians to maintain their space program through an infusion of American currency to maintain their status as one of the two premier space programs. While the United States built and launched the majority of the International Space Station, Russia, Canada, Japan, and the European Space Agency all contributed components. Despite NASA's insistence that costs would be kept at a budget of $17.4, they kept rising and NASA had to transfer funds from other programs to keep the International Space Station solvent. Ultimately, the total cost of the station was $150 billion, with the United States paying for two-thirds.Following the Space Shuttle Columbia disaster in 2003, NASA was forced to rely on Russian Soyuz launches for its astronauts and the 2011 retirement of the Space Shuttle accelerated the station's completion. In the 1980s, right after the first flight of the Space Shuttle, NASA started a joint program with the Department of Defense to develop the Rockwell X-30 National Aerospace Plane. NASA realized that the Space Shuttle, while a massive technological accomplishment, would not be able to live up to all its promises. Designed to be a single-stage-to-orbit spaceplane, the X-30 had both civil and military applications. With the end of the Cold War, the X-30 was canceled in 1992 before reaching flight status. === Unleashing commercial space and return to the Moon === Following the Space Shuttle Columbia disaster in 2003, President Bush started the Constellation program to smoothly replace the Space Shuttle and expand space exploration beyond low Earth orbit. Constellation was intended to use a significant amount of former Space Shuttle equipment and return astronauts to the Moon. This program was canceled by the Obama Administration. Former astronauts Neil Armstrong, Gene Cernan, and Jim Lovell sent a letter to President Barack Obama to warn him that if the United States did not get new human spaceflight ability, the US risked become a second or third-rate space power. As early as the Reagan Administration, there had been calls for NASA to expand private sector involvement in space exploration rather than do it all in-house. In the 1990s, NASA and Lockheed Martin entered into an agreement to develop the Lockheed Martin X-33 demonstrator of the VentureStar spaceplane, which was intended to replace the Space Shuttle. Due to technical challenges, the spacecraft was cancelled in 2001. Despite this, it was the first time a commercial space company directly expended a significant amount of its resources into spacecraft development. The advent of space tourism also forced NASA to challenge its assumption that only governments would have people in space. The first space tourist was Dennis Tito, an American investment manager and former aerospace engineer who contracted with the Russians to fly to the International Space Station for four days, despite the opposition of NASA to the idea. Advocates of this new commercial approach for NASA included former astronaut Buzz Aldrin, who remarked that it would return NASA to its roots as a research and development agency, with commercial entities actually operating the space systems. Having corporations take over orbital operations would also allow NASA to focus all its efforts on deep space exploration and returning humans to the Moon and going to Mars. Embracing this approach, NASA's Commercial Crew Program started by contracting cargo delivery to the International Space Station and flew its first operational contracted mission on SpaceX Crew-1. This marked the first time since the retirement of the Space Shuttle that NASA was able to launch its own astronauts on an American spacecraft from the United States, ending a decade of reliance on the Russians. In 2019, NASA announced the Artemis program, intending to return to the Moon and establish a permanent human presence. This was paired with the Artemis Accords with partner nations to establish rules of behavior and norms of space commercialization on the Moon. In 2023, NASA established the Moon to Mars Program office. The office is designed to oversee the various projects, mission architectures and associated timelines relevant to lunar and Mars exploration and science. == Active programs == === Human spaceflight === ==== International Space Station (1993–present) ==== The International Space Station (ISS) combines NASA's Space Station Freedom project with the Russian Mir-2 station, the European Columbus station, and the Japanese Kibō laboratory module. NASA originally planned in the 1980s to develop Freedom alone, but US budget constraints led to the merger of these projects into a single multi-national program in 1993, managed by NASA, the Russian Federal Space Agency (RKA), the Japan Aerospace Exploration Agency (JAXA), the European Space Agency (ESA), and the Canadian Space Agency (CSA). The station consists of pressurized modules, external trusses, solar arrays and other components, which were manufactured in various factories around the world and launched by Russian Proton and Soyuz rockets, and the American Space Shuttle. The on-orbit assembly began in 1998, the completion of the US Orbital Segment occurred in 2009 and the completion of the Russian Orbital Segment occurred in 2010. The ownership and use of the space station is established in intergovernmental treaties and agreements, which divide the station into two areas and allow Russia to retain full ownership of the Russian Orbital Segment (with the exception of Zarya), with the US Orbital Segment allocated between the other international partners. Long-duration missions to the ISS are referred to as ISS Expeditions. Expedition crew members typically spend approximately six months on the ISS. The initial expedition crew size was three, temporarily decreased to two following the Columbia disaster. Between May 2009 and until the retirement of the Space Shuttle, the expedition crew size has been six crew members. As of 2024, though the Commercial Program's crew capsules can allow a crew of up to seven, expeditions using them typically consist of a crew of four. The ISS has been continuously occupied for the past 24 years and 202 days, having exceeded the previous record held by Mir; and has been visited by astronauts and cosmonauts from 15 different nations. The station can be seen from the Earth with the naked eye and, as of 2025, is the largest artificial satellite in Earth orbit with a mass and volume greater than that of any previous space station. The Russian Soyuz and American Dragon and Starliner spacecraft are used to send astronauts to and from the ISS. Several uncrewed cargo spacecraft provide service to the ISS; they are the Russian Progress spacecraft which has done so since 2000, the European Automated Transfer Vehicle (ATV) since 2008, the Japanese H-II Transfer Vehicle (HTV) since 2009, the (uncrewed) Dragon since 2012, and the American Cygnus spacecraft since 2013. The Space Shuttle, before its retirement, was also used for cargo transfer and would often switch out expedition crew members, although it did not have the capability to remain docked for the duration of their stay. Between the retirement of the Shuttle in 2011 and the commencement of crewed Dragon flights in 2020, American astronauts exclusively used the Soyuz for crew transport to and from the ISS The highest number of people occupying the ISS has been thirteen; this occurred three times during the late Shuttle ISS assembly missions. The ISS program is expected to continue until 2030, after which the space station will be retired and destroyed in a controlled de-orbit. ==== Commercial Resupply Services (2008–present) ==== Commercial Resupply Services (CRS) are a contract solution to deliver cargo and supplies to the International Space Station on a commercial basis by private companies. NASA signed its first CRS contracts in 2008 and awarded $1.6 billion to SpaceX for twelve cargo Dragon and $1.9 billion to Orbital Sciences for eight Cygnus flights, covering deliveries until 2016. Both companies evolved or created their launch vehicle products to launch the spacecrafts (SpaceX with The Falcon 9 and Orbital with the Antares). SpaceX flew its first operational resupply mission (SpaceX CRS-1) in 2012. Orbital Sciences followed in 2014 (Cygnus CRS Orb-1). In 2015, NASA extended CRS-1 to twenty flights for SpaceX and twelve flights for Orbital ATK. A second phase of contracts (known as CRS-2) was solicited in 2014; contracts were awarded in January 2016 to Orbital ATK Cygnus, Sierra Nevada Corporation Dream Chaser, and SpaceX Dragon 2, for cargo transport flights beginning in 2019 and expected to last through 2024. In March 2022, NASA awarded an additional six CRS-2 missions each to both SpaceX and Northrop Grumman (formerly Orbital). Northrop Grumman successfully delivered Cygnus NG-17 to the ISS in February 2022. In July 2022, SpaceX launched its 25th CRS flight (SpaceX CRS-25) and successfully delivered its cargo to the ISS. The Dream Chaser spacecraft is currently scheduled for its Demo-1 launch in the first half of 2024. ==== Commercial Crew Program (2011–present) ==== The Commercial Crew Program (CCP) provides commercially operated crew transportation service to and from the International Space Station (ISS) under contract to NASA, conducting crew rotations between the expeditions of the International Space Station program. American space manufacturer SpaceX began providing service in 2020, using the Crew Dragon spacecraft, while Boeing's Starliner spacecraft began providing service in 2024. NASA has contracted for six operational missions from Boeing and fourteen from SpaceX, ensuring sufficient support for ISS through 2030. The spacecraft are owned and operated by the vendor, and crew transportation is provided to NASA as a commercial service. Each mission sends up to four astronauts to the ISS, with an option for a fifth passenger available. Operational flights occur approximately once every six months for missions that last for approximately six months. A spacecraft remains docked to the ISS during its mission, and missions usually overlap by at least a few days. Between the retirement of the Space Shuttle in 2011 and the first operational CCP mission in 2020, NASA relied on the Soyuz program to transport its astronauts to the ISS. A Crew Dragon spacecraft is launched to space atop a Falcon 9 Block 5 launch vehicle and the capsule returns to Earth via splashdown in the ocean near Florida. The program's first operational mission, SpaceX Crew-1, launched on November 16, 2020. Boeing Starliner operational flights will now commence with Boeing Starliner-1 which will launched atop an Atlas V N22 launch vehicle. Instead of a splashdown, Starliner capsules return on land with airbags at one of four designated sites in the western United States. ==== Artemis (2017–present) ==== Since 2017, NASA's crewed spaceflight program has been the Artemis program, which involves the help of US commercial spaceflight companies and international partners such as ESA, JAXA, and CSA. The goal of this program is to land "the first woman and the next man" on the lunar south pole region by 2025. Artemis would be the first step towards the long-term goal of establishing a sustainable presence on the Moon, laying the foundation for companies to build a lunar economy, and eventually sending humans to Mars. The Orion Crew Exploration Vehicle was held over from the canceled Constellation program for Artemis. Artemis I was the uncrewed initial launch of Space Launch System (SLS) that would also send an Orion spacecraft on a Distant Retrograde Orbit. The first tentative steps of returning to crewed lunar missions will be Artemis II, which is to include the Orion crew module, propelled by the SLS, and is expected to launch no later than April 2026. This mission is to be a 10-day mission planned to briefly place a crew of four into a Lunar flyby. Artemis III aims to conduct the first crewed lunar landing since Apollo 17, and is scheduled for no earlier than mid-2027. In support of the Artemis missions, NASA has been funding private companies to land robotic probes on the lunar surface in a program known as the Commercial Lunar Payload Services. As of March 2022, NASA has awarded contracts for robotic lunar probes to companies such as Intuitive Machines, Firefly Space Systems, and Astrobotic. On April 16, 2021, NASA announced they had selected the SpaceX Lunar Starship as its Human Landing System. The agency's Space Launch System rocket will launch four astronauts aboard the Orion spacecraft for their multi-day journey to lunar orbit where they will transfer to SpaceX's Starship for the final leg of their journey to the surface of the Moon. In November 2021, it was announced that the goal of landing astronauts on the Moon by 2024 had slipped to no earlier than 2027 due to numerous factors. Artemis I launched on November 16, 2022, and returned to Earth safely on December 11, 2022. As of April 2025, NASA plans to launch Artemis II in April 2026. and Artemis III in 2027. Additional Artemis missions, Artemis IV, Artemis V, and Artemis VI are planned to launch between 2028 and 2031. NASA's next major space initiative is the construction of the Lunar Gateway, a small space station in lunar orbit. This space station will be designed primarily for non-continuous human habitation. The construction of the Gateway is expected to begin in 2027 with the launch of the first two modules: the Power and Propulsion Element (PPE) and the Habitation and Logistics Outpost (HALO). Operations on the Gateway will begin with the Artemis IV mission, which plans to deliver a crew of four to the Gateway in 2028. In 2017, NASA was directed by the congressional NASA Transition Authorization Act of 2017 to get humans to Mars-orbit (or to the Martian surface) by the 2030s. ==== Commercial LEO Development (2021–present) ==== The Commercial Low Earth Orbit Destinations program is an initiative by NASA to support work on commercial space stations that the agency hopes to have in place by the end of the current decade to replace the "International Space Station". The three selected companies are: Blue Origin (et al.) with their Orbital Reef station concept, Nanoracks (et al.) with their Starlab Space Station concept, and Northrop Grumman with a station concept based on the HALO-module for the Gateway station. === Robotic exploration === NASA has conducted many uncrewed and robotic spaceflight programs throughout its history. More than 1,000 uncrewed missions have been designed to explore the Earth and the Solar System. ==== Mission selection process ==== NASA executes a mission development framework to plan, select, develop, and operate robotic missions. This framework defines cost, schedule and technical risk parameters to enable competitive selection of missions involving mission candidates that have been developed by principal investigators and their teams from across NASA, the broader US Government research and development stakeholders, and industry. The mission development construct is defined by four umbrella programs. ===== Explorer program ===== The Explorer program derives its origin from the earliest days of the US Space program. In current form, the program consists of three classes of systems – Small Explorers (SMEX), Medium Explorers (MIDEX), and University-Class Explorers (UNEX) missions. The NASA Explorer program office provides frequent flight opportunities for moderate cost innovative solutions from the heliophysics and astrophysics science areas. The Small Explorer missions are required to limit cost to NASA to below $150M (2022 dollars). Medium class explorer missions have typically involved NASA cost caps of $350M. The Explorer program office is based at NASA Goddard Space Flight Center. ===== Discovery program ===== The NASA Discovery program develops and delivers robotic spacecraft solutions in the planetary science domain. Discovery enables scientists and engineers to assemble a team to deliver a solution against a defined set of objectives and competitively bid that solution against other candidate programs. Cost caps vary but recent mission selection processes were accomplished using a $500M cost cap for NASA. The Planetary Mission Program Office is based at the NASA Marshall Space Flight Center and manages both the Discovery and New Frontiers missions. The office is part of the Science Mission Directorate. NASA Administrator Bill Nelson announced on June 2, 2021, that the DAVINCI+ and VERITAS missions were selected to launch to Venus in the late 2020s, having beat out competing proposals for missions to Jupiter's volcanic moon Io and Neptune's large moon Triton that were also selected as Discovery program finalists in early 2020. Each mission has an estimated cost of $500 million, with launches expected between 2028 and 2030. Launch contracts will be awarded later in each mission's development. ===== New Frontiers program ===== The New Frontiers program focuses on specific Solar System exploration goals identified as top priorities by the planetary science community. Primary objectives include Solar System exploration employing medium class spacecraft missions to conduct high-science-return investigations. New Frontiers builds on the development approach employed by the Discovery program but provides for higher cost caps and schedule durations than are available with Discovery. Cost caps vary by opportunity; recent missions have been awarded based on a defined cap of $1 billion. The higher cost cap and projected longer mission durations result in a lower frequency of new opportunities for the program – typically one every several years. OSIRIS-REx and New Horizons are examples of New Frontiers missions. NASA has determined that the next opportunity to propose for the fifth round of New Frontiers missions will occur no later than the fall of 2024. Missions in NASA's New Frontiers Program tackle specific Solar System exploration goals identified as top priorities by the planetary science community. Exploring the Solar System with medium-class spacecraft missions that conduct high-science-return investigations is NASA's strategy to further understand the Solar System. ===== Large strategic missions ===== Large strategic missions (formerly called Flagship missions) are strategic missions that are typically developed and managed by large teams that may span several NASA centers. The individual missions become the program as opposed to being part of a larger effort (see Discovery, New Frontiers, etc.). The James Webb Space Telescope is a strategic mission that was developed over a period of more than 20 years. Strategic missions are developed on an ad-hoc basis as program objectives and priorities are established. Missions like Voyager, had they been developed today, would have been strategic missions. Three of the Great Observatories were strategic missions (the Chandra X-ray Observatory, the Compton Gamma Ray Observatory, and the Hubble Space Telescope). Europa Clipper is the next large strategic mission in development by NASA. ==== Planetary science missions ==== NASA continues to play a material role in exploration of the Solar System as it has for decades. Ongoing missions have current science objectives with respect to more than five extraterrestrial bodies within the Solar System – Moon (Lunar Reconnaissance Orbiter), Mars (Perseverance rover), Jupiter (Juno), asteroid Bennu (OSIRIS-REx), and Kuiper Belt Objects (New Horizons). The Juno extended mission will make multiple flybys of the Jovian moon Io in 2023 and 2024 after flybys of Ganymede in 2021 and Europa in 2022. Voyager 1 and Voyager 2 continue to provide science data back to Earth while continuing on their outward journeys into interstellar space. On November 26, 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. The Curiosity rover successfully landed on Mars on August 6, 2012, and subsequently began its search for evidence of past or present life on Mars. In September 2014, NASA's MAVEN spacecraft, which is part of the Mars Scout Program, successfully entered Mars orbit and, as of October 2022, continues its study of the atmosphere of Mars. NASA's ongoing Mars investigations include in-depth surveys of Mars by the Perseverance rover. NASA's Europa Clipper, launched in October 2024, will study the Galilean moon Europa through a series of flybys while in orbit around Jupiter. Dragonfly will send a mobile robotic rotorcraft to Saturn's biggest moon, Titan. As of May 2021, Dragonfly is scheduled for launch in June 2027. ==== Astrophysics missions ==== The NASA Science Mission Directorate Astrophysics division manages the agency's astrophysics science portfolio. NASA has invested significant resources in the development, delivery, and operations of various forms of space telescopes. These telescopes have provided the means to study the cosmos over a large range of the electromagnetic spectrum. The Great Observatories that were launched in the 1980s and 1990s have provided a wealth of observations for study by physicists across the planent. The first of them, the Hubble Space Telescope, was delivered to orbit in 1990 and continues to function, in part due to prior servicing missions performed by the Space Shuttle. The other remaining active great observatories include the Chandra X-ray Observatory (CXO), launched by STS-93 in July 1999 and is now in a 64-hour elliptical orbit studying X-ray sources that are not readily viewable from terrestrial observatories. The Imaging X-ray Polarimetry Explorer (IXPE) is a space observatory designed to improve the understanding of X-ray production in objects such as neutron stars and pulsar wind nebulae, as well as stellar and supermassive black holes. IXPE launched in December 2021 and is an international collaboration between NASA and the Italian Space Agency (ASI). It is part of the NASA Small Explorers program (SMEX) which designs low-cost spacecraft to study heliophysics and astrophysics. The Neil Gehrels Swift Observatory was launched in November 2004 and is a gamma-ray burst observatory that also monitors the afterglow in X-ray, and UV/Visible light at the location of a burst. The mission was developed in a joint partnership between Goddard Space Flight Center (GSFC) and an international consortium from the United States, United Kingdom, and Italy. Pennsylvania State University operates the mission as part of NASA's Medium Explorer program (MIDEX). The Fermi Gamma-ray Space Telescope (FGST) is another gamma-ray focused space observatory that was launched to low Earth orbit in June 2008 and is being used to perform gamma-ray astronomy observations. In addition to NASA, the mission involves the United States Department of Energy, and government agencies in France, Germany, Italy, Japan, and Sweden. The James Webb Space Telescope (JWST), launched in December 2021 on an Ariane 5 rocket, operates in a halo orbit circling the Sun-Earth L2 point. JWST's high sensitivity in the infrared spectrum and its imaging resolution will allow it to view more distant, faint, or older objects than its predecessors, including Hubble. ==== Earth Sciences Program missions (1965–present) ==== NASA Earth Science is a large, umbrella program comprising a range of terrestrial and space-based collection systems in order to better understand the Earth system and its response to natural and human-caused changes. Numerous systems have been developed and fielded over several decades to provide improved prediction for weather, climate, and other changes in the natural environment. Several of the current operating spacecraft programs include: Aqua, Aura, Orbiting Carbon Observatory 2 (OCO-2), Gravity Recovery and Climate Experiment Follow-on (GRACE FO), and Ice, Cloud, and land Elevation Satellite 2 (ICESat-2). In addition to systems already in orbit, NASA is designing a new set of Earth Observing Systems to study, assess, and generate responses for climate change, natural hazards, forest fires, and real-time agricultural processes. The GOES-T satellite (designated GOES-18 after launch) joined the fleet of US geostationary weather monitoring satellites in March 2022. NASA also maintains the Earth Science Data Systems (ESDS) program to oversee the life cycle of NASA's Earth science data – from acquisition through processing and distribution. The primary goal of ESDS is to maximize the scientific return from NASA's missions and experiments for research and applied scientists, decision makers, and society at large. The Earth Science program is managed by the Earth Science Division of the NASA Science Mission Directorate. === Space operations architecture === NASA invests in various ground and space-based infrastructures to support its science and exploration mandate. The agency maintains access to suborbital and orbital space launch capabilities and sustains ground station solutions to support its evolving fleet of spacecraft and remote systems. ==== Deep Space Network (1963–present) ==== The NASA Deep Space Network (DSN) serves as the primary ground station solution for NASA's interplanetary spacecraft and select Earth-orbiting missions. The system employs ground station complexes near Barstow, California, in Spain near Madrid, and in Australia near Canberra. The placement of these ground stations approximately 120 degrees apart around the planet provides the ability for communications to spacecraft throughout the Solar System even as the Earth rotates about its axis on a daily basis. The system is controlled at a 24x7 operations center at JPL in Pasadena, California, which manages recurring communications linkages with up to 40 spacecraft. The system is managed by the Jet Propulsion Laboratory. ==== Near Space Network (1983–present) ==== The Near Space Network (NSN) provides telemetry, commanding, ground-based tracking, data and communications services to a wide range of customers with satellites in low earth orbit (LEO), geosynchronous orbit (GEO), highly elliptical orbits (HEO), and lunar orbits. The NSN accumulates ground station and antenna assets from the Near-Earth Network and the Tracking and Data Relay Satellite System (TDRS) which operates in geosynchronous orbit providing continuous real-time coverage for launch vehicles and low earth orbit NASA missions. The NSN consists of 19 ground stations worldwide operated by the US Government and by contractors including Kongsberg Satellite Services (KSAT), Swedish Space Corporation (SSC), and South African National Space Agency (SANSA). The ground network averages between 120 and 150 spacecraft contacts a day with TDRS engaging with systems on a near-continuous basis as needed; the system is managed and operated by the Goddard Space Flight Center. ==== Sounding Rocket Program (1959–present) ==== The NASA Sounding Rocket Program (NSRP) is located at the Wallops Flight Facility and provides launch capability, payload development and integration, and field operations support to execute suborbital missions. The program has been in operation since 1959 and is managed by the Goddard Space Flight Center using a combined US Government and contractor team. The NSRP team conducts approximately 20 missions per year from both Wallops and other launch locations worldwide to allow scientists to collect data "where it occurs". The program supports the strategic vision of the Science Mission Directorate collecting important scientific data for earth science, heliophysics, and astrophysics programs. In June 2022, NASA conducted its first rocket launch from a commercial spaceport outside the US. It launched a Black Brant IX from the Arnhem Space Centre in Australia. ==== Launch Services Program (1990–present) ==== The NASA Launch Services Program (LSP) is responsible for procurement of launch services for NASA uncrewed missions and oversight of launch integration and launch preparation activity, providing added quality and mission assurance to meet program objectives. Since 1990, NASA has purchased expendable launch vehicle launch services directly from commercial providers, whenever possible, for its scientific and applications missions. Expendable launch vehicles can accommodate all types of orbit inclinations and altitudes and are ideal vehicles for launching Earth-orbit and interplanetary missions. LSP operates from Kennedy Space Center and falls under the NASA Space Operations Mission Directorate (SOMD). === Aeronautics Research === The Aeronautics Research Mission Directorate (ARMD) is one of five mission directorates within NASA, the other four being the Exploration Systems Development Mission Directorate, the Space Operations Mission Directorate, the Science Mission Directorate, and the Space Technology Mission Directorate. The ARMD is responsible for NASA's aeronautical research, which benefits the commercial, military, and general aviation sectors. ARMD performs its aeronautics research at four NASA facilities: Ames Research Center and Armstrong Flight Research Center in California, Glenn Research Center in Ohio, and Langley Research Center in Virginia. ==== NASA X-57 Maxwell aircraft (2016–present) ==== The NASA X-57 Maxwell is an experimental aircraft being developed by NASA to demonstrate the technologies required to deliver a highly efficient all-electric aircraft. The primary goal of the program is to develop and deliver all-electric technology solutions that can also achieve airworthiness certification with regulators. The program involves development of the system in several phases, or modifications, to incrementally grow the capability and operability of the system. The initial configuration of the aircraft has now completed ground testing as it approaches its first flights. In mid-2022, the X-57 was scheduled to fly before the end of the year. The development team includes staff from the NASA Armstrong, Glenn, and Langley centers along with number of industry partners from the United States and Italy. ==== Next Generation Air Transportation System (2007–present) ==== NASA is collaborating with the Federal Aviation Administration and industry stakeholders to modernize the United States National Airspace System (NAS). Efforts began in 2007 with a goal to deliver major modernization components by 2025. The modernization effort intends to increase the safety, efficiency, capacity, access, flexibility, predictability, and resilience of the NAS while reducing the environmental impact of aviation. The Aviation Systems Division of NASA Ames operates the joint NASA/FAA North Texas Research Station. The station supports all phases of NextGen research, from concept development to prototype system field evaluation. This facility has already transitioned advanced NextGen concepts and technologies to use through technology transfers to the FAA. NASA contributions also include development of advanced automation concepts and tools that provide air traffic controllers, pilots, and other airspace users with more accurate real-time information about the nation's traffic flow, weather, and routing. Ames' advanced airspace modeling and simulation tools have been used extensively to model the flow of air traffic flow across the US, and to evaluate new concepts in airspace design, traffic flow management, and optimization. === Technology research === ==== Nuclear in-space power and propulsion (ongoing) ==== NASA has made use of technologies such as the multi-mission radioisotope thermoelectric generator (MMRTG), which is a type of radioisotope thermoelectric generator used to power spacecraft. Shortages of the required plutonium-238 have curtailed deep space missions since the turn of the millennium. An example of a spacecraft that was not developed because of a shortage of this material was New Horizons 2. In July 2021, NASA announced contract awards for development of nuclear thermal propulsion reactors. Three contractors will develop individual designs over 12 months for later evaluation by NASA and the US Department of Energy. NASA's space nuclear technologies portfolio are led and funded by its Space Technology Mission Directorate. In January 2023, NASA announced a partnership with Defense Advanced Research Projects Agency (DARPA) on the Demonstration Rocket for Agile Cislunar Operations (DRACO) program to demonstrate a NTR engine in space, an enabling capability for NASA missions to Mars. In July 2023, NASA and DARPA jointly announced the award of $499 million to Lockheed Martin to design and build an experimental NTR rocket to be launched in 2027. ==== Other initiatives ==== Free Space Optics. NASA contracted a third party to study the probability of using Free Space Optics (FSO) to communicate with Optical (laser) Stations on the Ground (OGS) called laser-com RF networks for satellite communications. Water Extraction from Lunar Soil. On July 29, 2020, NASA requested American universities to propose new technologies for extracting water from the lunar soil and developing power systems. The idea will help the space agency conduct sustainable exploration of the Moon. In 2024, NASA was tasked by the US Government to create a Time standard for the Moon. The standard is to be called Coordinated Lunar Time and is expected to be finalized in 2026. === Human Spaceflight Research (2005–present) === NASA's Human Research Program (HRP) is designed to study the effects of space on human health and also to provide countermeasures and technologies for human space exploration. The medical effects of space exploration are reasonably limited in low Earth orbit or in travel to the Moon. Travel to Mars is significantly longer and deeper into space, significant medical issues can result. These include bone density loss, radiation exposure, vision changes, circadian rhythm disturbances, heart remodeling, and immune alterations. In order to study and diagnose these ill-effects, HRP has been tasked with identifying or developing small portable instrumentation with low mass, volume, and power to monitor the health of astronauts. To achieve this aim, on May 13, 2022, NASA and SpaceX Crew-4 astronauts successfully tested its rHEALTH ONE universal biomedical analyzer for its ability to identify and analyzer biomarkers, cells, microorganisms, and proteins in a spaceflight environment. === Planetary Defense (2016–present) === NASA established the Planetary Defense Coordination Office (PDCO) in 2016 to catalog and track potentially hazardous near-Earth objects (NEO), such as asteroids and comets and develop potential responses and defenses against these threats. The PDCO is chartered to provide timely and accurate information to the government and the public on close approaches by Potentially hazardous objects (PHOs) and any potential for impact. The office functions within the Science Mission Directorate Planetary Science Division. The PDCO augmented prior cooperative actions between the United States, the European Union, and other nations which had been scanning the sky for NEOs since 1998 in an effort called Spaceguard. ==== Near Earth object detection (1998–present) ==== From the 1990s NASA has run many NEO detection programs from Earth bases observatories, greatly increasing the number of objects that have been detected. Many asteroids are very dark and those near the Sun are much harder to detect from Earth-based telescopes which observe at night, and thus face away from the Sun. NEOs inside Earth orbit only reflect a part of light also rather than potentially a "full Moon" when they are behind the Earth and fully lit by the Sun. In 1998, the United States Congress gave NASA a mandate to detect 90% of near-Earth asteroids over 1 km (0.62 mi) diameter (that threaten global devastation) by 2008. This initial mandate was met by 2011. In 2005, the original USA Spaceguard mandate was extended by the George E. Brown, Jr. Near-Earth Object Survey Act, which calls for NASA to detect 90% of NEOs with diameters of 140 m (460 ft) or greater, by 2020 (compare to the 20-meter Chelyabinsk meteor that hit Russia in 2013). As of January 2020, it is estimated that less than half of these have been found, but objects of this size hit the Earth only about once in 2,000 years. In January 2020, NASA officials estimated it would take 30 years to find all objects meeting the 140 m (460 ft) size criteria, more than twice the timeframe that was built into the 2005 mandate. In June 2021, NASA authorized the development of the NEO Surveyor spacecraft to reduce that projected duration to achieve the mandate down to 10 years. ==== Involvement in current robotic missions ==== NASA has incorporated planetary defense objectives into several ongoing missions. In 1999, NASA visited 433 Eros with the NEAR Shoemaker spacecraft which entered its orbit in 2000, closely imaging the asteroid with various instruments at that time. NEAR Shoemaker became the first spacecraft to successfully orbit and land on an asteroid, improving our understanding of these bodies and demonstrating our capacity to study them in greater detail. OSIRIS-REx used its suite of instruments to transmit radio tracking signals and capture optical images of Bennu during its study of the asteroid that will help NASA scientists determine its precise position in the solar system and its exact orbital path. As Bennu has the potential for recurring approaches to the Earth-Moon system in the next 100–200 years, the precision gained from OSIRIS-REx will enable scientists to better predict the future gravitational interactions between Bennu and our planet and resultant changes in Bennu's onward flight path. The WISE/NEOWISE mission was launched by NASA JPL in 2009 as an infrared-wavelength astronomical space telescope. In 2013, NASA repurposed it as the NEOWISE mission to find potentially hazardous near-Earth asteroids and comets; its mission has been extended into 2023. NASA and Johns Hopkins Applied Physics Laboratory (JHAPL) jointly developed the first planetary defense purpose-built satellite, the Double Asteroid Redirection Test (DART) to test possible planetary defense concepts. DART was launched in November 2021 by a SpaceX Falcon 9 from California on a trajectory designed to impact the Dimorphos asteroid. Scientists were seeking to determine whether an impact could alter the subsequent path of the asteroid; a concept that could be applied to future planetary defense. On September 26, 2022, DART hit its target. In the weeks following impact, NASA declared DART a success, confirming it had shortened Dimorphos' orbital period around Didymos by about 32 minutes, surpassing the pre-defined success threshold of 73 seconds. NEO Surveyor, formerly called the Near-Earth Object Camera (NEOCam) mission, is a space-based infrared telescope under development to survey the Solar System for potentially hazardous asteroids. The spacecraft is scheduled to launch in 2026. === Study of Unidentified Aerial Phenomena (2022–present) === In June 2022, the head of the NASA Science Mission Directorate, Thomas Zurbuchen, confirmed the start of NASA's UAP independent study team. At a speech before the National Academies of Science, Engineering and Medicine, Zurbuchen said the space agency would bring a scientific perspective to efforts already underway by the Pentagon and intelligence agencies to make sense of dozens of such sightings. He said it was "high-risk, high-impact" research that the space agency should not shy away from, even if it is a controversial field of study. == Collaboration == === NASA Advisory Council === In response to the Apollo 1 accident, which killed three astronauts in 1967, Congress directed NASA to form an Aerospace Safety Advisory Panel (ASAP) to advise the NASA Administrator on safety issues and hazards in NASA's air and space programs. In the aftermath of the Shuttle Columbia disaster, Congress required that the ASAP submit an annual report to the NASA Administrator and to Congress. By 1971, NASA had also established the Space Program Advisory Council and the Research and Technology Advisory Council to provide the administrator with advisory committee support. In 1977, the latter two were combined to form the NASA Advisory Council (NAC). The NASA Authorization Act of 2014 reaffirmed the importance of ASAP. === National Oceanic and Atmospheric Administration (NOAA) === NASA and NOAA have cooperated for decades on the development, delivery and operation of polar and geosynchronous weather satellites. The relationship typically involves NASA developing the space systems, launch solutions, and ground control technology for the satellites and NOAA operating the systems and delivering weather forecasting products to users. Multiple generations of NOAA Polar orbiting platforms have operated to provide detailed imaging of weather from low altitude. Geostationary Operational Environmental Satellites (GOES) provide near-real-time coverage of the western hemisphere to ensure accurate and timely understanding of developing weather phenomenon. === United States Space Force === The United States Space Force (USSF) is the space service branch of the United States Armed Forces, while the National Aeronautics and Space Administration (NASA) is an independent agency of the United States government responsible for civil spaceflight. NASA and the Space Force's predecessors in the Air Force have a long-standing cooperative relationship, with the Space Force supporting NASA launches out of Kennedy Space Center, Cape Canaveral Space Force Station, and Vandenberg Space Force Base, to include range support and rescue operations from Task Force 45. NASA and the Space Force also partner on matters such as defending Earth from asteroids. Space Force members can be NASA astronauts, with Colonel Michael S. Hopkins, the commander of SpaceX Crew-1, commissioned into the Space Force from the International Space Station on December 18, 2020. In September 2020, the Space Force and NASA signed a memorandum of understanding formally acknowledging the joint role of both agencies. This new memorandum replaced a similar document signed in 2006 between NASA and Air Force Space Command. === US Geological Survey === The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On July 23, 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975. The most recent satellite in the series, Landsat 9, was launched on September 27, 2021. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the US Geological Survey (USGS) "EarthExplorer" website. The collaboration between NASA and USGS involves NASA designing and delivering the space system (satellite) solution, launching the satellite into orbit with the USGS operating the system once in orbit. As of October 2022, nine satellites have been built with eight of them successfully operating in orbit. === European Space Agency (ESA) === NASA collaborates with the European Space Agency on a wide range of scientific and exploration requirements. From participation with the Space Shuttle (the Spacelab missions) to major roles on the Artemis program (the Orion Service Module), ESA and NASA have supported the science and exploration missions of each agency. There are NASA payloads on ESA spacecraft and ESA payloads on NASA spacecraft. The agencies have developed joint missions in areas including heliophysics (e.g. Solar Orbiter) and astronomy (Hubble Space Telescope, James Webb Space Telescope). Under the Artemis Gateway partnership, ESA will contribute habitation and refueling modules, along with enhanced lunar communications, to the Gateway. NASA and ESA continue to advance cooperation in relation to Earth Science including climate change with agreements to cooperate on various missions including the Sentinel-6 series of spacecraft === Japan Aerospace Exploration Agency (JAXA) === NASA and the Japan Aerospace Exploration Agency (JAXA) cooperate on a range of space projects. JAXA is a direct participant in the Artemis program, including the Lunar Gateway effort. JAXA's planned contributions to Gateway include I-Hab's environmental control and life support system, batteries, thermal control, and imagery components, which will be integrated into the module by the European Space Agency (ESA) prior to launch. These capabilities are critical for sustained Gateway operations during crewed and uncrewed time periods. JAXA and NASA have collaborated on numerous satellite programs, especially in areas of Earth science. NASA has contributed to JAXA satellites and vice versa. Japanese instruments are flying on NASA's Terra and Aqua satellites, and NASA sensors have flown on previous Japanese Earth-observation missions. The NASA-JAXA Global Precipitation Measurement mission was launched in 2014 and includes both NASA- and JAXA-supplied sensors on a NASA satellite launched on a JAXA rocket. The mission provides the frequent, accurate measurements of rainfall over the entire globe for use by scientists and weather forecasters. === Roscosmos === NASA and Roscosmos have cooperated on the development and operation of the International Space Station since September 1993. The agencies have used launch systems from both countries to deliver station elements to orbit. Astronauts and Cosmonauts jointly maintain various elements of the station. Both countries provide access to the station via launch systems noting Russia's unique role as the sole provider of delivery of crew and cargo upon retirement of the space shuttle in 2011 and prior to commencement of NASA COTS and crew flights. In July 2022, NASA and Roscosmos signed a deal to share space station flights enabling crew from each country to ride on the systems provided by the other. Current geopolitical conditions in late 2022 make it unlikely that cooperation will be extended to other programs such as Artemis or lunar exploration. === Indian Space Research Organisation (ISRO) === In September 2014, NASA and Indian Space Research Organisation (ISRO) signed a partnership to collaborate on and launch a joint radar mission, the NASA-ISRO Synthetic Aperature Radar (NISAR) mission. The mission is targeted to launch in June 2025. NASA will provide the mission's L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO provides the spacecraft bus, the S-band radar, the launch vehicle and associated launch services. === Artemis Accords === The Artemis Accords have been established to define a framework for cooperating in the peaceful exploration and exploitation of the Moon, Mars, asteroids, and comets. The accords were drafted by NASA and the US State Department and are executed as a series of bilateral agreements between the United States and the participating countries. As of September 2022, 21 countries have signed the accords. They are Australia, Bahrain, Brazil, Canada, Colombia, France, Israel, Italy, Japan, the Republic of Korea, Luxembourg, Mexico, New Zealand, Poland, Romania, the Kingdom of Saudi Arabia, Singapore, Ukraine, the United Arab Emirates, the United Kingdom, and the United States. === China National Space Administration === The Wolf Amendment was passed by the US Congress into law in 2011 and prevents NASA from engaging in direct, bilateral cooperation with the Chinese government and China-affiliated organizations such as the China National Space Administration without the explicit authorization from Congress and the Federal Bureau of Investigation. The law has been renewed annually since by inclusion in annual appropriations bills. == Management == === Leadership === The agency's administration is located at NASA Headquarters in Washington, DC, and provides overall guidance and direction. Except under exceptional circumstances, NASA civil service employees are required to be US citizens. NASA's administrator is nominated by the President of the United States subject to the approval of the US Senate, and serves at the President's pleasure as a senior space science advisor. The current administrator is Janet Petro, appointed as acting administrator by President Donald Trump, since January 20, 2025. The Trump administration has also nominated Jared Isaacman as official administrator of NASA; however, Senate has yet to confirm him to the position. === Strategic plan === NASA operates with four FY2022 strategic goals. Expand human knowledge through new scientific discoveries Extend human presence to the Moon and on towards Mars for sustainable long-term exploration, development, and utilization Catalyze economic growth and drive innovation to address national challenges Enhance capabilities and operations to catalyze current and future mission success === Budget === NASA budget requests are developed by NASA and approved by the administration prior to submission to the US Congress. Authorized budgets are those that have been included in enacted appropriations bills that are approved by both houses of Congress and enacted into law by the US president. NASA fiscal year budget requests and authorized budgets are listed below. === Organization === NASA funding and priorities are developed through its six Mission Directorates. Center-wide activities such as the Chief Engineer and Safety and Mission Assurance organizations are aligned to the headquarters function. The MSD budget estimate includes funds for these HQ functions. The administration operates 10 major field centers with several managing additional subordinate facilities across the country. Each center is led by a director (data below valid as of December 23, 2024). == Sustainability == === Environmental impact === The exhaust gases produced by rocket propulsion systems, both in Earth's atmosphere and in space, can adversely affect the Earth's environment. Some hypergolic rocket propellants, such as hydrazine, are highly toxic prior to combustion, but decompose into less toxic compounds after burning. Rockets using hydrocarbon fuels, such as kerosene, release carbon dioxide and soot in their exhaust. Carbon dioxide emissions are insignificant compared to those from other sources; on average, the United States consumed 803 million US gal (3.0 million m3) of liquid fuels per day in 2014, while a single Falcon 9 rocket first stage burns around 25,000 US gallons (95 m3) of kerosene fuel per launch. Even if a Falcon 9 were launched every single day, it would only represent 0.006% of liquid fuel consumption (and carbon dioxide emissions) for that day. Additionally, the exhaust from LOx- and LH2- fueled engines, like the SSME, is almost entirely water vapor. NASA addressed environmental concerns with its canceled Constellation program in accordance with the National Environmental Policy Act in 2011. In contrast, ion engines use harmless noble gases like xenon for propulsion. An example of NASA's environmental efforts is the NASA Sustainability Base. Additionally, the Exploration Sciences Building was awarded the LEED Gold rating in 2010. On May 8, 2003, the Environmental Protection Agency recognized NASA as the first federal agency to directly use landfill gas to produce energy at one of its facilities—the Goddard Space Flight Center, Greenbelt, Maryland. In 2018, NASA along with other companies including Sensor Coating Systems, Pratt & Whitney, Monitor Coating and UTRC launched the project CAUTION (CoAtings for Ultra High Temperature detectION). This project aims to enhance the temperature range of the Thermal History Coating up to 1,500 °C (2,730 °F) and beyond. The final goal of this project is improving the safety of jet engines as well as increasing efficiency and reducing CO2 emissions. === Climate change === NASA also researches and publishes on climate change. Its statements concur with the global scientific consensus that the climate is warming. Bob Walker, who has advised former US President Donald Trump on space issues, has advocated that NASA should focus on space exploration and that its climate study operations should be transferred to other agencies such as NOAA. Former NASA atmospheric scientist J. Marshall Shepherd countered that Earth science study was built into NASA's mission at its creation in the 1958 National Aeronautics and Space Act. NASA won the 2020 Webby People's Voice Award for Green in the category Web. === STEM Initiatives === Educational Launch of Nanosatellites (ELaNa). Since 2011, the ELaNa program has provided opportunities for NASA to work with university teams to test emerging technologies and commercial-off-the-shelf solutions by providing launch opportunities for developed CubeSats using NASA procured launch opportunities. By example, two NASA-sponsored CubeSats launched in June 2022 on a Virgin Orbit LauncherOne vehicle as the ELaNa 39 mission. Cubes in Space. NASA started an annual competition in 2014 named "Cubes in Space". It is jointly organized by NASA and the global education company I Doodle Learning, with the objective of teaching school students aged 11–18 to design and build scientific experiments to be launched into space on a NASA rocket or balloon. On June 21, 2017, the world's smallest satellite, KalamSAT, was launched. === Use of the metric system === US law requires the International System of Units to be used in all US Government programs, "except where impractical". In 1969, Apollo 11 landed on the Moon using a mix of United States customary units and metric units. In the 1980s, NASA started the transition towards the metric system, but was still using both systems in the 1990s. On September 23, 1999, a mixup between NASA's use of SI units and Lockheed Martin Space's use of US units resulted in the loss of the Mars Climate Orbiter. In August 2007, NASA stated that all future missions and explorations of the Moon would be done entirely using the SI system. This was done to improve cooperation with space agencies of other countries that already use the metric system. As of 2007, NASA is predominantly working with SI units, but some projects still use US units, and some, including the International Space Station, use a mix of both. == Media presence == === NASA TV === Approaching 40 years of service, the NASA TV channel airs content ranging from live coverage of crewed missions to video coverage of significant milestones for operating robotic spacecraft (e.g. rover landings on Mars) and domestic and international launches. The channel is delivered by NASA and is broadcast by satellite and over the Internet. The system initially started to capture archival footage of important space events for NASA managers and engineers and expanded as public interest grew. The Apollo 8 Christmas Eve broadcast while in orbit around the Moon was received by more than a billion people. NASA's video transmission of the Apollo 11 Moon landing was awarded a primetime Emmy in commemoration of the 40th anniversary of the landing. The channel is a product of the US Government and is widely available across many television and Internet platforms. === NASAcast === NASAcast is the official audio and video podcast of the NASA website. Created in late 2005, the podcast service contains the latest audio and video features from the NASA web site, including NASA TV's This Week at NASA and educational materials produced by NASA. Additional NASA podcasts, such as Science@NASA, are also featured and give subscribers an in-depth look at content by subject matter. === NASA EDGE === NASA EDGE is a video podcast which explores different missions, technologies and projects developed by NASA. The program was released by NASA on March 18, 2007, and, as of August 2020, there have been 200 vodcasts produced. It is a public outreach vodcast sponsored by NASA's Exploration Systems Mission Directorate and based out of the Exploration and Space Operations Directorate at Langley Research Center in Hampton, Virginia. The NASA EDGE team takes an insider's look at current projects and technologies from NASA facilities around the United States, and it is depicted through personal interviews, on-scene broadcasts, computer animations, and personal interviews with top scientists and engineers at NASA. The show explores the contributions NASA has made to society as well as the progress of current projects in materials and space exploration. NASA EDGE vodcasts can be downloaded from the NASA website and from iTunes. In its first year of production, the show was downloaded over 450,000 times. As of February 2010, the average download rate is more than 420,000 per month, with over one million downloads in December 2009 and January 2010. NASA and the NASA EDGE have also developed interactive programs designed to complement the vodcast. The Lunar Electric Rover App allows users to drive a simulated Lunar Electric Rover between objectives, and it provides information about and images of the vehicle. The NASA EDGE Widget provides a graphical user interface for accessing NASA EDGE vodcasts, image galleries, and the program's Twitter feed, as well as a live NASA news feed. === Astronomy Picture of the Day === === NASA+ === In July 2023, NASA announced a new streaming service known as NASA+. It launched on November 8, 2023, and has live coverage of launches, documentaries and original programs. According to NASA, it will be free of ads and subscription fees. It will be a part of the NASA app on iOS, Android, Amazon Fire TV, Roku and Apple TV as well as on the web on desktop and mobile devices. == Gallery == == See also == List of crewed spacecraft List of NASA aircraft List of space disasters List of United States rockets Category: NASA people NASA Advanced Space Transportation Program NASA Art Program NASA Clean Air Study – 1989 study of plants removing air pollutants NASA Institute for Advanced Concepts – NASA program NASA Research Park – Research park near San Jose, California TechPort (NASA) – Technology Portfolio System == Explanatory notes == == References == == Further reading == Alexander, Joseph K. Science Advice to NASA: Conflict, Consensus, Partnership, Leadership (2019) excerpt Bizony, Piers et al. The NASA Archives. 60 Years in Space (2019) Brady, Kevin M. "NASA Launches Houston into Orbit How America's Space Program Contributed to Southeast Texas's Economic Growth, Scientific Development, and Modernization during the Late Twentieth Century." Journal of the West (2018) 57#4 pp 13–54. Bromberg, Joan Lisa. NASA and the Space Industry (Johns Hopkins UP, 1999). Clemons, Jack. Safely to Earth: The Men and Women Who Brought the Astronauts Home (2018) excerpt Dick, Steven J., and Roger D. Launius, eds. Critical Issues in the History of Spaceflight (NASA, 2006) Launius, Roger D. "Eisenhower, Sputnik, and the Creation of NASA." Prologue-Quarterly of the National Archives 28.2 (1996): 127–143. Pyle, Rod. Space 2.0: How Private Spaceflight, a Resurgent NASA, and International Partners are Creating a New Space Age (2019), overview of space exploration excerpt Spencer, Brett. "The Book and the Rocket: The Symbiotic Relationship between American Public Libraries and the Space Program, 1950–2015", Information & Culture 51, no. 4 (2016): 550–582. Weinzierl, Matthew. "Space, the final economic frontier." Journal of Economic Perspectives 32.2 (2018): 173–192. online Archived December 31, 2021, at the Wayback Machine, review of economics literature == External links == Official website NASA Watch, an agency watchdog site Works by or about NASA at the Internet Archive How NASA works on howstuffworks.com
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Formal science is a branch of science studying disciplines concerned with abstract structures described by formal systems, such as logic, mathematics, statistics, theoretical computer science, artificial intelligence, information theory, game theory, systems theory, decision theory and theoretical linguistics. Whereas the natural sciences and social sciences seek to characterize physical systems and social systems, respectively, using theoretical and empirical methods, the formal sciences use language tools concerned with characterizing abstract structures described by formal systems and the deductions that can be made from them. The formal sciences aid the natural and social sciences by providing information about the structures used to describe the physical world, and what inferences may be made about them. == Branches == Logic (also a branch of philosophy) Mathematics Statistics Systems science Data science Information theory Computer science Cryptography == Differences from other sciences == One reason why mathematics enjoys special esteem, above all other sciences, is that its laws are absolutely certain and indisputable, while those of other sciences are to some extent debatable and in constant danger of being overthrown by newly discovered facts. Because of their non-empirical nature, formal sciences are construed by outlining a set of axioms and definitions from which other statements (theorems) are deduced. For this reason, in Rudolf Carnap's logical-positivist conception of the epistemology of science, theories belonging to formal sciences are understood to contain no synthetic statements, instead containing only analytic statements. == See also == == References == == Further reading == Mario Bunge (1985). Philosophy of Science and Technology. Springer. Mario Bunge (1998). Philosophy of Science. Rev. ed. of: Scientific research. Berlin, New York: Springer-Verlag, 1967. C. West Churchman (1940). Elements of Logic and Formal Science, J.B. Lippincott Co., New York. James Franklin (1994). The formal sciences discover the philosophers' stone. In: Studies in History and Philosophy of Science. Vol. 25, No. 4, pp. 513–533, 1994 Stephen Leacock (1906). Elements of Political Science. Houghton, Mifflin Co, 417 pp. Popper, Karl R. (2002) [1959]. The Logic of Scientific Discovery. New York, NY: Routledge Classics. ISBN 0-415-27844-9. OCLC 59377149. Bernt P. Stigum (1990). Toward a Formal Science of Economics. MIT Press Marcus Tomalin (2006), Linguistics and the Formal Sciences. Cambridge University Press William L. Twining (1997). Law in Context: Enlarging a Discipline. 365 pp. == External links == Media related to Formal sciences at Wikimedia Commons Interdisciplinary conferences — Foundations of the Formal Sciences
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Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities. == History == The Duboscq colorimeter was invented by Jules Duboscq in 1870. == Instruments == Colorimetric equipment is similar to that used in spectrophotometry. Some related equipment is also mentioned for completeness. A tristimulus colorimeter measures the tristimulus values of a color. A spectroradiometer measures the absolute spectral radiance (intensity) or irradiance of a light source. A spectrophotometer measures the spectral reflectance, transmittance, or relative irradiance of a color sample. A spectrocolorimeter is a spectrophotometer that can calculate tristimulus values. A densitometer measures the degree of light passing through or reflected by a subject. A color temperature meter measures the color temperature of an incident illuminant. === Tristimulus colorimeter === In digital imaging, colorimeters are tristimulus devices used for color calibration. Accurate color profiles ensure consistency throughout the imaging workflow, from acquisition to output. === Spectroradiometer, spectrophotometer, spectrocolorimeter === The absolute spectral power distribution of a light source can be measured with a spectroradiometer, which works by optically collecting the light, then passing it through a monochromator before reading it in narrow bands of wavelength. Reflected color can be measured using a spectrophotometer (also called spectroreflectometer or reflectometer), which takes measurements in the visible region (and a little beyond) of a given color sample. If the custom of taking readings at 10 nanometer increments is followed, the visible light range of 400–700 nm will yield 31 readings. These readings are typically used to draw the sample's spectral reflectance curve (how much it reflects, as a function of wavelength)—the most accurate data that can be provided regarding its characteristics. The readings by themselves are typically not as useful as their tristimulus values, which can be converted into chromaticity co-ordinates and manipulated through color space transformations. For this purpose, a spectrocolorimeter may be used. A spectrocolorimeter is simply a spectrophotometer that can estimate tristimulus values by numerical integration (of the color matching functions' inner product with the illuminant's spectral power distribution). One benefit of spectrocolorimeters over tristimulus colorimeters is that they do not have optical filters, which are subject to manufacturing variance, and have a fixed spectral transmittance curve—until they age. On the other hand, tristimulus colorimeters are purpose-built, cheaper, and easier to use. The CIE (International Commission on Illumination) recommends using measurement intervals under 5 nm, even for smooth spectra. Sparser measurements fail to accurately characterize spiky emission spectra, such as that of the red phosphor of a CRT display, depicted aside. === Color temperature meter === Photographers and cinematographers use information provided by these meters to decide what color balancing should be done to make different light sources appear to have the same color temperature. If the user enters the reference color temperature, the meter can calculate the mired difference between the measurement and the reference, enabling the user to choose a corrective color gel or photographic filter with the closest mired factor. Internally the meter is typically a silicon photodiode tristimulus colorimeter. The correlated color temperature can be calculated from the tristimulus values by first calculating the chromaticity co-ordinates in the CIE 1960 color space, then finding the closest point on the Planckian locus. == See also == Color science Photometry Radiometry == References == == Further reading == Schanda, János D. (1997). "Colorimetry" (PDF). In Casimer DeCusatis (ed.). Handbook of Applied Photometry. OSA/AIP. pp. 327–412. ISBN 978-1-56396-416-9. Archived from the original (PDF) on 17 September 2005. Retrieved 17 July 2008. Bala, Raja (2003). "Device Characterization" (PDF). In Gaurav Sharma (ed.). Digital Color Imaging Handbook. CRC Press. ISBN 978-0-8493-0900-7. Archived from the original (PDF) on 28 May 2008. Retrieved 5 May 2008. Gardner, James L. (May–June 2007). "Comparison of Calibration Methods for Tristimulus Colorimeters" (PDF). Journal of Research of the National Institute of Standards and Technology. 112 (3): 129–138. doi:10.6028/jres.112.010. PMC 4656001. PMID 27110460. S2CID 1949232. Archived from the original (PDF) on 28 May 2008. Retrieved 2 February 2008. MacEvoy, Bruce (8 May 2008). "Overview of the development and applications of colorimetry". Handprint.com. Retrieved 17 July 2008. Optronik – Photometers An informative brochure with background information and specifications of their equipment. Konica Minolta Sensing – Precise Color Communication – from perception to instrumentation HunterLab – FAQ | How to Measure Color of a Sample & Use An Index A guide to measuring color and appearance of objects. The section provides information on numerical scales and indices that are used throughout the world to remove subjective measurements and assumptions. NIST Publications related to colorimetry. == External links == Colorlab MATLAB toolbox for color science computation and accurate color reproduction (by Jesus Malo and Maria Jose Luque, Universitat de Valencia). It includes CIE standard tristimulus colorimetry and transformations to a number of non-linear color appearance models (CIE Lab, CIE CAM, etc.).
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Design science research (DSR) is a research paradigm focusing on the development and validation of prescriptive knowledge in information science. Herbert Simon distinguished the natural sciences, concerned with explaining how things are, from design sciences which are concerned with how things ought to be, that is, with devising artifacts to attain goals. Design science research methodology (DSRM) refers to the research methodologies associated with this paradigm. It spans the methodologies of several research disciplines, for example information technology, which offers specific guidelines for evaluation and iteration within research projects. DSR focuses on the development and performance of (designed) artifacts with the explicit intention of improving the functional performance of the artifact. DSRM is typically applied to categories of artifacts including algorithms, human/computer interfaces, design methodologies (including process models) and languages. Its application is most notable in the Engineering and Computer Science disciplines, though is not restricted to these and can be found in many disciplines and fields. DSR, or constructive research, in contrast to explanatory science research, has academic research objectives generally of a more pragmatic nature. Research in these disciplines can be seen as a quest for understanding and improving human performance. Such renowned research institutions as the MIT Media Lab, Stanford University's Center for Design Research, Carnegie Mellon University's Software Engineering Institute, Xerox’s PARC, and Brunel University London’s Organisation and System Design Centre, use the DSR approach. Design science is a valid research methodology to develop solutions for practical engineering problems. Design science is particularly suitable for wicked problems. == Objectives == The main goal of DSR is to develop knowledge that professionals of the discipline in question can use to design solutions for their field problems. Design sciences focus on the process of making choices on what is possible and useful for the creation of possible futures, rather than on what is currently existing. This mission can be compared to that of the ‘explanatory sciences’, like the natural sciences and sociology, which is to develop knowledge to describe, explain and predict. Hevner states that the main purpose of DSR is achieving knowledge and understanding of a problem domain by building and application of a designed artifact. == Evolution and applications == Since the first days of computer science, computer scientists have been doing DSR without naming it. They have developed new architectures for computers, new programming languages, new compilers, new algorithms, new data and file structures, new data models, new database management systems, and so on. Much of the early research was focused on systems development approaches and methods. The dominant research philosophy in many disciplines has focused on developing cumulative, theory-based research results in order to make prescriptions. It seems that this ‘theory-with-practical-implications’ research strategy has not delivered on this aim, which led to search for practical research methods such as DSR. == Characteristics == The design process is a sequence of expert activities that produces an innovative product. The artifact enables the researcher to get a better grasp of the problem; the re-evaluation of the problem improves the quality of the design process and so on. This build-and-evaluate loop is typically iterated a number of times before the final design artifact is generated. In DSR, the focus is on the so-called field-tested and grounded technological rule as a possible product of Mode 2 research with the potential to improve the relevance of academic research in management. Mode 1 knowledge production is purely academic and mono-disciplinary, while Mode 2 is multidisciplinary and aims at solving complex and relevant field problems. == Guidelines in information systems research == Hevner et al. have presented a set of guidelines for DSR within the discipline of Information Systems (IS). DSR requires the creation of an innovative, purposeful artifact for a special problem domain. The artifact must be evaluated in order to ensure its utility for the specified problem. In order to form a novel research contribution, the artifact must either solve a problem that has not yet been solved, or provide a more effective solution. Both the construction and evaluation of the artifact must be done rigorously, and the results of the research presented effectively both to technology-oriented and management-oriented audiences. Hevner counts 7 guidelines for a DSR: Design as an artifact: Design-science research must produce a viable artifact in the form of a construct, a model, a method, or an instantiation. Problem relevance: The objective of design-science research is to develop technology-based solutions to important and relevant business problems. Design evaluation: The utility, quality, and efficacy of a design artifact must be rigorously demonstrated via well-executed evaluation methods. Research contributions: Effective design-science research must provide clear and verifiable contributions in the areas of the design artifact, design foundations, and/or design methodologies. Research rigor: Design-science research relies upon the application of rigorous methods in both the construction and evaluation of the design artifact. Design as a search process: The search for an effective artifact requires utilizing available means to reach desired ends while satisfying laws in the problem environment. Communication of research: Design-science research must be presented effectively both to technology-oriented as well as management-oriented audiences. Transparency in DSR is becoming an emerging concern. DSR strives to be practical and relevant. Yet few researchers have examined the extent to which practitioners can meaningfully utilize theoretical knowledge produced by DSR in solving concrete real-world problems. There is a potential gulf between theoretical propositions and concrete issues faced in practice—a challenge known as design theory indeterminacy. Guidelines for addressing this challenges are provided in Lukyanenko et al. 2020. == The engineering cycle and the design cycle == The engineering cycle is a framework used in Design Science for Information Systems and Software Engineering, proposed by Roel Wieringa. == Artifacts == Artifacts within DSR are perceived to be knowledge containing. This knowledge ranges from the design logic, construction methods and tool to assumptions about the context in which the artifact is intended to function (Gregor, 2002). The creation and evaluation of artifacts thus forms an important part in the DSR process which was described by Hevner et al., (2004) and supported by March and Storey (2008) as revolving around “build and evaluate”. DSR artifacts can broadly include: models, methods, constructs, instantiations and design theories (March & Smith, 1995; Gregor 2002; March & Storey, 2008, Gregor and Hevner 2013), social innovations, new or previously unknown properties of technical/social/informational resources (March, Storey, 2008), new explanatory theories, new design and developments models and implementation processes or methods (Ellis & Levy 2010). == A three-cycle view == DSR can be seen as an embodiment of three closely related cycles of activities. The relevance cycle initiates DSR with an application context that not only provides the requirements for the research as inputs but also defines acceptance criteria for the ultimate evaluation of the research results. The rigor cycle provides past knowledge to the research project to ensure its innovation. It is incumbent upon the researchers to thoroughly research and reference the knowledge base in order to guarantee that the designs produced are research contributions and not routine designs based upon the application of well-known processes. The central design cycle iterates between the core activities of building and evaluating the design artifacts and processes of the research. == Ethical issues == DSR in itself implies an ethical change from describing and explaining of the existing world to shaping it. One can question the values of information system research, i.e., whose values and what values dominate it, emphasizing that research may openly or latently serve the interests of particular dominant groups. The interests served may be those of the host organization as perceived by its top management, those of information system users, those of information system professionals or potentially those of other stakeholder groups in society. == Academic Examples of Design Science Research == There are limited references to examples of DSR, but Adams has completed two PhD research topics using Peffers et al.'s DSRP (both associated with digital forensics but from different perspectives): 2013: The Advanced Data Acquisition Model (ADAM): A process model for digital forensic practice 2024: The Advanced Framework for Evaluating Remote Agents (AFERA): A Framework for Digital Forensic Practitioners == See also == Empirical research Action research Participant observation Case study Design thinking == References == == Research examples == Adams, R., Hobbs, V., Mann, G., (2013). The Advanced Data Acquisition Model (ADAM): A process model for digital forensic practice. URL: http://researchrepository.murdoch.edu.au/id/eprint/14422/2/02Whole.pdf == Further reading == March, S. T., Smith, G. F., (1995). Design and natural science research on information technology. Decision Support Systems, 15(4), pp. 251–266. March, S. T., Storey, V. C., (2008). Design Science in the Information Systems Discipline: An introduction to the special issue on design science research, MIS Quarterly, Vol. 32(4), pp. 725–730. Mettler T, Eurich M, Winter R (2014). "On the Use of Experiments in Design Science Research: A Proposition of an Evaluation Framework". Communications of the AIS. 34 (1): 223–240. Opdenakker, Raymond en Carin Cuijpers (2019),’Effective Virtual Project Teams: A Design Science Approach to Building a Strategic Momentum’, Springer Verlag. Van Aken, J. E. (2004). Management Research Based on the Paradigm of the Design Sciences: The Quest for Field-Tested and Grounded Technological Rules. Journal of Management Studies, 41(2), 219–246. Watts S, Shankaranarayanan G., Even A. Data quality assessment in context: A cognitive perspective. Decis Support Syst. 2009;48(1):202-211. == External links == Design Science Research in Information System and Technology community
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Management science (or managerial science) is a wide and interdisciplinary study of solving complex problems and making strategic decisions as it pertains to institutions, corporations, governments and other types of organizational entities. It is closely related to management, economics, business, engineering, management consulting, and other fields. It uses various scientific research-based principles, strategies, and analytical methods including mathematical modeling, statistics and numerical algorithms and aims to improve an organization's ability to enact rational and accurate management decisions by arriving at optimal or near optimal solutions to complex decision problems.: 113 Management science looks to help businesses achieve goals using a number of scientific methods. The field was initially an outgrowth of applied mathematics, where early challenges were problems relating to the optimization of systems which could be modeled linearly, i.e., determining the optima (maximum value of profit, assembly line performance, crop yield, bandwidth, etc. or minimum of loss, risk, costs, etc.) of some objective function. Today, the discipline of management science may encompass a diverse range of managerial and organizational activity as it regards to a problem which is structured in mathematical or other quantitative form in order to derive managerially relevant insights and solutions. == Overview == Management science is concerned with a number of areas of study: Developing and applying models and concepts that may prove useful in helping to illuminate management issues and solve managerial problems. The models used can often be represented mathematically, but sometimes computer-based, visual or verbal representations are used as well or instead. Designing and developing new and better models of organizational excellence. Helping to improve, stabilize or otherwise manage profit margins in enterprises. Management science research can be done on three levels: The fundamental level lies in three mathematical disciplines: probability, optimization, and dynamical systems theory. The modeling level is about building models, analyzing them mathematically, gathering and analyzing data, implementing models on computers, solving them, experimenting with them—all this is part of management science research on the modeling level. This level is mainly instrumental, and driven mainly by statistics and econometrics. The application level, just as in any other engineering and economics disciplines, strives to make a practical impact and be a driver for change in the real world. The management scientist's mandate is to use rational, systematic and science-based techniques to inform and improve decisions of all kinds. The techniques of management science are not restricted to business applications but may be applied to military, medical, public administration, charitable groups, political groups or community groups. The norm for scholars in management science is to focus their work in a certain area or subfield of management like public administration, finance, calculus, information and so forth. == History == Although management science as it exists now covers a myriad of topics having to do with coming up with solutions that increase the efficiency of a business, it was not even a field of study in the not too distant past. There are a number of businessmen and management specialists who can receive credit for the creation of the idea of management science. Most commonly, however, the founder of the field is considered to be Frederick Winslow Taylor in the early 20th century. Likewise, administration expert Luther Gulick and management expert Peter Drucker both had an impact on the development of management science in the 1930s and 1940s. Drucker is quoted as having said that, "the purpose of the corporation is to be economically efficient." This thought process is foundational to management science. Even before the influence of these men, there was Louis Brandeis who became known as "the people's lawyer". In 1910, Brandeis was the creator of a new business approach which he coined as "scientific management", a term that is often falsely attributed to the aforementioned Frederick Winslow Taylor. These men represent some of the earliest ideas of management science at its conception. After the idea was born, it was further explored around the time of World War II. It was at this time that management science became more than an idea and was put into practice. This sort of experimentation was essential to the development of the field as it is known today. The origins of management science can be traced to operations research, which became influential during World War II when the Allied forces recruited scientists of various disciplines to assist with military operations. In these early applications, the scientists used simple mathematical models to make efficient use of limited technologies and resources. The application of these models to the corporate sector became known as management science. In 1967 Stafford Beer characterized the field of management science as "the business use of operations research". == Theory == Some of the fields that management science involves include: == Applications == Management science's applications are diverse allowing the use of it in many fields. Below are examples of the applications of management science. In finance, management science is instrumental in portfolio optimization, risk management, and investment strategies. By employing mathematical models, analysts can assess market trends, optimize asset allocation, and mitigate financial risks, contributing to more informed and strategic decision-making. In healthcare, management science plays a crucial role in optimizing resource allocation, patient scheduling, and facility management. Mathematical models aid healthcare professionals in streamlining operations, reducing waiting times, and improving overall efficiency in the delivery of care. Logistics and supply chain management benefit significantly from management science applications. Optimization algorithms assist in route planning, inventory management, and demand forecasting, enhancing the efficiency of the entire supply chain. In manufacturing, management science supports process optimization, production planning, and quality control. Mathematical models help identify bottlenecks, reduce production costs, and enhance overall productivity. Furthermore, management science contributes to strategic decision-making in project management, marketing, and human resources. By leveraging quantitative techniques, organizations can make data-driven decisions, allocate resources effectively, and enhance overall performance across diverse functional areas. == See also == == References == == Further reading == Kenneth R. Baker, Dean H. Kropp (1985). Management Science: An Introduction to the Use of Decision Models David Charles Heinze (1982). Management Science: Introductory Concepts and Applications Lee J. Krajewski, Howard E. Thompson (1981). "Management Science: Quantitative Methods in Context" Thomas W. Knowles (1989). Management science: Building and Using Models Kamlesh Mathur, Daniel Solow (1994). Management Science: The Art of Decision Making Laurence J. Moore, Sang M. Lee, Bernard W. Taylor (1993). Management Science William Thomas Morris (1968). Management Science: A Bayesian Introduction. William E. Pinney, Donald B. McWilliams (1987). Management Science: An Introduction to Quantitative Analysis for Management Gerald E. Thompson (1982). Management Science: An Introduction to Modern Quantitative Analysis and Decision Making. New York : McGraw-Hill Publishing Co.
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Creation science or scientific creationism is a pseudoscientific form of Young Earth creationism which claims to offer scientific arguments for certain literalist and inerrantist interpretations of the Bible. It is often presented without overt faith-based language, but instead relies on reinterpreting scientific results to argue that various myths in the Book of Genesis and other select biblical passages are scientifically valid. The most commonly advanced ideas of creation science include special creation based on the Genesis creation narrative and flood geology based on the Genesis flood narrative. Creationists also claim they can disprove or reexplain a variety of scientific facts, theories and paradigms of geology, cosmology, biological evolution, archaeology, history, and linguistics using creation science. Creation science was foundational to intelligent design. The overwhelming consensus of the scientific community is that creation science fails to qualify as scientific because it lacks empirical support, supplies no testable hypotheses, and resolves to describe natural history in terms of scientifically untestable supernatural causes. Courts, most often in the United States where the question has been asked in the context of teaching the subject in public schools, have consistently ruled since the 1980s that creation science is a religious view rather than a scientific one. Historians, philosophers of science and skeptics have described creation science as a pseudoscientific attempt to map the Bible into scientific facts. Professional biologists have criticized creation science for being unscholarly, and even as a dishonest and misguided sham, with extremely harmful educational consequences. == Beliefs and activities == === Religious basis === Creation science is based largely upon chapters 1–11 of the Book of Genesis. These describe how God calls the world into existence through the power of speech ("And God said, Let there be light," etc.) in six days, calls all the animals and plants into existence, and molds the first man from clay and the first woman from a rib taken from the man's side; a worldwide flood destroys all life except for Noah and his family and representatives of the animals, and Noah becomes the ancestor of the 70 "nations" of the world; the nations live together until the incident of the Tower of Babel, when God disperses them and gives them their different languages. Creation science attempts to explain history and science within the span of Biblical chronology, which places the initial act of creation some six thousand years ago. === Modern religious affiliations === Most creation science proponents hold fundamentalist or Evangelical Christian beliefs in Biblical literalism or Biblical inerrancy, as opposed to the higher criticism supported by liberal Christianity in the Fundamentalist–Modernist Controversy. However, there are also examples of Islamic and Jewish scientific creationism that conform to the accounts of creation as recorded in their religious doctrines. The Seventh-day Adventist Church has a history of support for creation science. This dates back to George McCready Price, an active Seventh-day Adventist who developed views of flood geology, which formed the basis of creation science. This work was continued by the Geoscience Research Institute, an official institute of the Seventh-day Adventist Church, located on its Loma Linda University campus in California. Creation science is generally rejected by the Church of England as well as the Roman Catholic Church. The Pontifical Gregorian University has officially discussed intelligent design as a "cultural phenomenon" without scientific elements. The Church of England's official website cites Charles Darwin's local work assisting people in his religious parish. === Views on science === Creation science rejects evolution and the common descent of all living things on Earth. Instead, it asserts that the field of evolutionary biology is itself pseudoscientific or even a religion. Creationists argue instead for a system called baraminology, which considers the living world to be descended from uniquely created kinds or "baramins." Creation science incorporates the concept of catastrophism to reconcile current landforms and fossil distributions with Biblical interpretations, proposing the remains resulted from successive cataclysmic events, such as a worldwide flood and subsequent ice age. It rejects one of the fundamental principles of modern geology (and of modern science generally), uniformitarianism, which applies the same physical and geological laws observed on the Earth today to interpret the Earth's geological history. Sometimes creationists attack other scientific concepts, like the Big Bang cosmological model or methods of scientific dating based upon radioactive decay. Young Earth creationists also reject current estimates of the age of the universe and the age of the Earth, arguing for creationist cosmologies with timescales much shorter than those determined by modern physical cosmology and geological science, typically less than 10,000 years. The scientific community has overwhelmingly rejected the ideas put forth in creation science as lying outside the boundaries of a legitimate science. The foundational premises underlying scientific creationism disqualify it as a science because the answers to all inquiry therein are preordained to conform to Bible doctrine, and because that inquiry is constructed upon theories which are not empirically testable in nature. Scientists also deem creation science's attacks against biological evolution to be without scientific merit. The views of the scientific community were accepted in two significant court decisions in the 1980s, which found the field of creation science to be a religious mode of inquiry, not a scientific one. == History == Creation science began in the 1960s, as a fundamentalist Christian effort in the United States to prove Biblical inerrancy and nullify the scientific evidence for evolution. It has since developed a sizable religious following in the United States, with creation science ministries branching worldwide. The main ideas in creation science are: the belief in creation ex nihilo (Latin: out of nothing); the conviction that the Earth was created within the last 6,000–10,000 years; the belief that humans and other life on Earth were created as distinct fixed "baraminological" kinds; and "flood geology" or the idea that fossils found in geological strata were deposited during a cataclysmic flood which completely covered the entire Earth. As a result, creationists also challenge the geologic and astrophysical measurements of the age of the Earth and the universe along with their origins, which creationists believe are irreconcilable with the account in the Book of Genesis. Creation science proponents often refer to the theory of evolution as "Darwinism" or as "Darwinian evolution." The creation science texts and curricula that first emerged in the 1960s focused upon concepts derived from a literal interpretation of the Bible and were overtly religious in nature, most notably proposing Noah's flood in the Biblical Genesis account as an explanation for the geological and fossil record. These works attracted little notice beyond the schools and congregations of conservative fundamental and Evangelical Christians until the 1970s, when its followers challenged the teaching of evolution in the public schools and other venues in the United States, bringing it to the attention of the public-at-large and the scientific community. Many school boards and lawmakers were persuaded to include the teaching of creation science alongside evolution in the science curriculum. Creation science texts and curricula used in churches and Christian schools were revised to eliminate their Biblical and theological references, and less explicitly sectarian versions of creation science education were introduced in public schools in Louisiana, Arkansas, and other regions in the United States. The 1982 ruling in McLean v. Arkansas found that creation science fails to meet the essential characteristics of science and that its chief intent is to advance a particular religious view. The teaching of creation science in public schools in the United States effectively ended in 1987 following the United States Supreme Court decision in Edwards v. Aguillard. The court affirmed that a statute requiring the teaching of creation science alongside evolution when evolution is taught in Louisiana public schools was unconstitutional because its sole true purpose was to advance a particular religious belief. In response to this ruling, drafts of the creation science school textbook Of Pandas and People were edited to change references of creation to intelligent design before its publication in 1989. The intelligent design movement promoted this version. Requiring intelligent design to be taught in public school science classes was found to be unconstitutional in the 2005 Kitzmiller v. Dover Area School District federal court case. === Before 1960s === The teaching of evolution was gradually introduced into more and more public high school textbooks in the United States after 1900, but in the aftermath of the First World War the growth of fundamentalist Christianity gave rise to a creationist opposition to such teaching. Legislation prohibiting the teaching of evolution was passed in certain regions, most notably Tennessee's Butler Act of 1925. The Soviet Union's successful launch of Sputnik 1 in 1957 sparked national concern that the science education in public schools was outdated. In 1958, the United States passed National Defense Education Act which introduced new education guidelines for science instruction. With federal grant funding, the Biological Sciences Curriculum Study (BSCS) drafted new standards for the public schools' science textbooks which included the teaching of evolution. Almost half the nation's high schools were using textbooks based on the guidelines of the BSCS soon after they were published in 1963. The Tennessee legislature did not repeal the Butler Act until 1967. Creation science (dubbed "scientific creationism" at the time) emerged as an organized movement during the 1960s. It was strongly influenced by the earlier work of armchair geologist George McCready Price who wrote works such as Illogical Geology: The Weakest Point in the Evolution Theory (1906) and The New Geology (1923) to advance what he termed "new catastrophism" and dispute the current geological time frames and explanations of geologic history. Price was cited at the Scopes Trial of 1925, but his writings had no credence among geologists and other scientists. Price's "new catastrophism" was also disputed by most other creationists until its revival with the 1961 publication of The Genesis Flood by John C. Whitcomb and Henry M. Morris, a work which quickly became an important text on the issue to fundamentalist Christians and expanded the field of creation science beyond critiques of geology into biology and cosmology as well. Soon after its publication, a movement was underway to have the subject taught in United States' public schools. === Court determinations === The various state laws prohibiting teaching of evolution were overturned in 1968 when the United States Supreme Court ruled in Epperson v. Arkansas such laws violated the Establishment Clause of the First Amendment to the United States Constitution. This ruling inspired a new creationist movement to promote laws requiring that schools give balanced treatment to creation science when evolution is taught. The 1981 Arkansas Act 590 was one such law that carefully detailed the principles of creation science that were to receive equal time in public schools alongside evolutionary principles. The act defined creation science as follows: "'Creation-science' means the scientific evidences for creation and inferences from those evidences. Creation-science includes the scientific evidences and related inferences that indicate: Sudden creation of the universe, and, in particular, life, from nothing; The insufficiency of mutation and natural selection in bringing about development of all living kinds from a single organism; Changes only with fixed limits of originally created kinds of plants and animals; Separate ancestry for man and apes; Explanation of the earth's geology by catastrophism, including the occurrence of worldwide flood; and A relatively recent inception of the earth and living kinds." This legislation was examined in McLean v. Arkansas, and the ruling handed down on January 5, 1982, concluded that creation-science as defined in the act "is simply not science". The judgement defined the following as essential characteristics of science: It is guided by natural law; It has to be explanatory by reference to nature law; It is testable against the empirical world; Its conclusions are tentative, i.e., are not necessarily the final word; and It is falsifiable. The court ruled that creation science failed to meet these essential characteristics and identified specific reasons. After examining the key concepts from creation science, the court found: Sudden creation "from nothing" calls upon a supernatural intervention, not natural law, and is neither testable nor falsifiable Objections in creation science that mutation and natural selection are insufficient to explain common origins was an incomplete negative generalization 'Kinds' are not scientific classifications, and creation science's claims of an outer limit to the evolutionary change possible of species are not explained scientifically or by natural law The separate ancestry of man and apes is an assertion rather than a scientific explanation, and did not derive from any scientific fact or theory Catastrophism, including its identification of the worldwide flood, failed as a science "Relatively recent inception" was the product of religious readings and had no scientific meaning, and was neither the product of, nor explainable by, natural law; nor is it tentative The court further noted that no recognized scientific journal had published any article espousing the creation science theory as described in the Arkansas law, and stated that the testimony presented by defense attributing the absence to censorship was not credible. In its ruling, the court wrote that for any theory to qualify as scientific, the theory must be tentative, and open to revision or abandonment as new facts come to light. It wrote that any methodology which begins with an immutable conclusion that cannot be revised or rejected, regardless of the evidence, is not a scientific theory. The court found that creation science does not culminate in conclusions formed from scientific inquiry, but instead begins with the conclusion, one taken from a literal wording of the Book of Genesis, and seeks only scientific evidence to support it. The law in Arkansas adopted the same two-model approach as that put forward by the Institute for Creation Research, one allowing only two possible explanations for the origins of life and existence of man, plants and animals: it was either the work of a creator or it was not. Scientific evidence that failed to support the theory of evolution was posed as necessarily scientific evidence in support of creationism, but in its judgment the court ruled this approach to be no more than a "contrived dualism which has not scientific factual basis or legitimate educational purpose." The judge concluded that "Act 590 is a religious crusade, coupled with a desire to conceal this fact," and that it violated the First Amendment's Establishment Clause. The decision was not appealed to a higher court, but had a powerful influence on subsequent rulings. Louisiana's 1982 Balanced Treatment for Creation-Science and Evolution-Science Act, authored by State Senator Bill P. Keith, judged in the 1987 United States Supreme Court case Edwards v. Aguillard, and was handed a similar ruling. It found the law to require the balanced teaching of creation science with evolution had a particular religious purpose and was therefore unconstitutional. === Intelligent design splits off === In 1984, The Mystery of Life's Origin was first published. It was co-authored by chemist and creationist Charles B. Thaxton with Walter L. Bradley and Roger L. Olsen, the foreword written by Dean H. Kenyon, and sponsored by the Christian-based Foundation for Thought and Ethics (FTE). The work presented scientific arguments against current theories of abiogenesis and offered a hypothesis of special creation instead. While the focus of creation science had until that time centered primarily on the criticism of the fossil evidence for evolution and validation of the creation myth of the Bible, this new work posed the question whether science reveals that even the simplest living systems were far too complex to have developed by natural, unguided processes. Kenyon later co-wrote with creationist Percival Davis a book intended as a "scientific brief for creationism" to use as a supplement to public high school biology textbooks. Thaxton was enlisted as the book's editor, and the book received publishing support from the FTE. Prior to its release, the 1987 Supreme Court ruling in Edwards v. Aguillard barred the teaching of creation science and creationism in public school classrooms. The book, originally titled Biology and Creation but renamed Of Pandas and People, was released in 1989 and became the first published work to promote the anti-evolutionist design argument under the name intelligent design. The contents of the book later became a focus of evidence in the federal court case, Kitzmiller v. Dover Area School District, when a group of parents filed suit to halt the teaching of intelligent design in Dover, Pennsylvania, public schools. School board officials there had attempted to include Of Pandas and People in their biology classrooms and testimony given during the trial revealed the book was originally written as a creationist text but following the adverse decision in the Supreme Court it underwent simple cosmetic editing to remove the explicit allusions to "creation" or "creator," and replace them instead with references to "design" or "designer." By the mid-1990s, intelligent design had become a separate movement. The creation science movement is distinguished from the intelligent design movement, or neo-creationism, because most advocates of creation science accept scripture as a literal and inerrant historical account, and their primary goal is to corroborate the scriptural account through the use of science. In contrast, as a matter of principle, neo-creationism eschews references to scripture altogether in its polemics and stated goals (see Wedge strategy). By so doing, intelligent design proponents have attempted to succeed where creation science has failed in securing a place in public school science curricula. Carefully avoiding any reference to the identity of the intelligent designer as God in their public arguments, intelligent design proponents sought to reintroduce the creationist ideas into science classrooms while sidestepping the First Amendment's prohibition against religious infringement. However, the intelligent design curriculum was struck down as a violation of the Establishment Clause in Kitzmiller v. Dover Area School District, the judge in the case ruled "that ID is nothing less than the progeny of creationism." Today, creation science as an organized movement is primarily centered within the United States. Creation science organizations are also known in other countries, most notably Creation Ministries International which was founded (under the name Creation Science Foundation) in Australia. Proponents are usually aligned with a Christian denomination, primarily with those characterized as evangelical, conservative, or fundamentalist. While creationist movements also exist in Islam and Judaism, these movements do not use the phrase creation science to describe their beliefs. == Issues == Creation science has its roots in the work of young Earth creationist George McCready Price disputing modern science's account of natural history, focusing particularly on geology and its concept of uniformitarianism, and his efforts instead to furnish an alternative empirical explanation of observable phenomena which was compatible with strict Biblical literalism. Price's work was later discovered by civil engineer Henry M. Morris, who is now considered to be the father of creation science. Morris and later creationists expanded the scope with attacks against the broad spectrum scientific findings that point to the antiquity of the Universe and common ancestry among species, including growing body of evidence from the fossil record, absolute dating techniques, and cosmogony. The proponents of creation science often say that they are concerned with religious and moral questions as well as natural observations and predictive hypotheses. Many state that their opposition to scientific evolution is primarily based on religion. The overwhelming majority of scientists are in agreement that the claims of science are necessarily limited to those that develop from natural observations and experiments which can be replicated and substantiated by other scientists, and that claims made by creation science do not meet those criteria. Duane Gish, a prominent creation science proponent, has similarly claimed, "We do not know how the creator created, what processes He used, for He used processes which are not now operating anywhere in the natural universe. This is why we refer to creation as special creation. We cannot discover by scientific investigation anything about the creative processes used by the Creator." But he also makes the same claim against science's evolutionary theory, maintaining that on the subject of origins, scientific evolution is a religious theory which cannot be validated by science. === Metaphysical assumptions === Creation science makes the a priori metaphysical assumption that there exists a creator of the life whose origin is being examined. Christian creation science holds that the description of creation is given in the Bible, that the Bible is inerrant in this description (and elsewhere), and therefore empirical scientific evidence must correspond with that description. Creationists also view the preclusion of all supernatural explanations within the sciences as a doctrinaire commitment to exclude the supreme being and miracles. They claim this to be the motivating factor in science's acceptance of Darwinism, a term used in creation science to refer to evolutionary biology which is also often used as a disparagement. Critics argue that creation science is religious rather than scientific because it stems from faith in a religious text rather than by the application of the scientific method. The United States National Academy of Sciences (NAS) has stated unequivocally, "Evolution pervades all biological phenomena. To ignore that it occurred or to classify it as a form of dogma is to deprive the student of the most fundamental organizational concept in the biological sciences. No other biological concept has been more extensively tested and more thoroughly corroborated than the evolutionary history of organisms." Anthropologist Eugenie Scott has noted further, "Religious opposition to evolution propels antievolutionism. Although antievolutionists pay lip service to supposed scientific problems with evolution, what motivates them to battle its teaching is apprehension over the implications of evolution for religion." Creation science advocates argue that scientific theories of the origins of the Universe, Earth, and life are rooted in a priori presumptions of methodological naturalism and uniformitarianism, each of which they reject. In some areas of science such as chemistry, meteorology or medicine, creation science proponents do not necessarily challenge the application of naturalistic or uniformitarian assumptions, but instead single out those scientific theories they judge to be in conflict with their religious beliefs, and it is against those theories that they concentrate their efforts. === Religious criticism === Many mainstream Christian churches criticize creation science on theological grounds, asserting either that religious faith alone should be a sufficient basis for belief in the truth of creation, or that efforts to prove the Genesis account of creation on scientific grounds are inherently futile because reason is subordinate to faith and cannot thus be used to prove it. Many Christian theologies, including Liberal Christianity, consider the Genesis creation narrative to be a poetic and allegorical work rather than a literal history, and many Christian churches—including the Eastern Orthodox Church, the Roman Catholic, Anglican and the more liberal denominations of the Lutheran, Methodist, Congregationalist and Presbyterian faiths—have either rejected creation science outright or are ambivalent to it. Belief in non-literal interpretations of Genesis is often cited as going back to Saint Augustine. Theistic evolution and evolutionary creationism are theologies that reconcile belief in a creator with biological evolution. Each holds the view that there is a creator but that this creator has employed the natural force of evolution to unfold a divine plan. Religious representatives from faiths compatible with theistic evolution and evolutionary creationism have challenged the growing perception that belief in a creator is inconsistent with the acceptance of evolutionary theory. Spokespersons from the Catholic Church have specifically criticized biblical creationism for relying upon literal interpretations of biblical scripture as the basis for determining scientific fact. === Scientific criticism === The National Academy of Sciences states that "the claims of creation science lack empirical support and cannot be meaningfully tested" and that "creation science is in fact not science and should not be presented as such in science classes." According to Joyce Arthur writing for Skeptic magazine, the "creation 'science' movement gains much of its strength through the use of distortion and scientifically unethical tactics" and "seriously misrepresents the theory of evolution." Scientists have considered the hypotheses proposed by creation science and have rejected them because of a lack of evidence. Furthermore, the claims of creation science do not refer to natural causes and cannot be subject to meaningful tests, so they do not qualify as scientific hypotheses. In 1987, the United States Supreme Court ruled that creationism is religion, not science, and cannot be advocated in public school classrooms. Most mainline Christian denominations have concluded that the concept of evolution is not at odds with their descriptions of creation and human origins. A summary of the objections to creation science by scientists follows: Creation science is not falsifiable: An idea or hypothesis is generally not considered to be in the realm of science unless it can be potentially disproved with certain experiments, this is the concept of falsifiability in science. The act of creation as defined in creation science is not falsifiable because no testable bounds can be imposed on the creator. In creation science, the creator is defined as limitless, with the capacity to create (or not), through fiat alone, infinite universes, not just one, and endow each one with its own unique, unimaginable and incomparable character. It is impossible to disprove a claim when that claim as defined encompasses every conceivable contingency. Creation science violates the principle of parsimony: Parsimony favours those explanations which rely on the fewest assumptions. Scientists prefer explanations that are consistent with known and supported facts and evidence and require the fewest assumptions to fill the remaining gaps. Many of the alternative claims made in creation science retreat from simpler scientific explanations and introduce more complications and conjecture into the equation. Creation science is not, and cannot be, empirically or experimentally tested: Creationism posits supernatural causes which lie outside the realm of methodological naturalism and scientific experiment. Science can only test empirical, natural claims. Creation science is not correctable, dynamic, tentative or progressive: Creation science adheres to a fixed and unchanging premise or "absolute truth," the "word of God," which is not open to change. Any evidence that runs contrary to that truth must be disregarded. In science, all claims are tentative, they are forever open to challenge, and must be discarded or adjusted when the weight of evidence demands it. By invoking claims of "abrupt appearance" of species as a miraculous act, creation science is unsuited for the tools and methods demanded by science, and it cannot be considered scientific in the way that the term "science" is currently defined. Scientists and science writers commonly characterize creation science as a pseudoscience. === Historical, philosophical, and sociological criticism === Historically, the debate of whether creationism is compatible with science can be traced back to 1874, the year science historian John William Draper published his History of the Conflict between Religion and Science. In it Draper portrayed the entire history of scientific development as a war against religion. This presentation of history was propagated further by followers such as Andrew Dickson White in his two-volume A History of the Warfare of Science with Theology in Christendom (1896). Their conclusions have been disputed. In the United States, the principal focus of creation science advocates is on the government-supported public school systems, which are prohibited by the Establishment Clause from promoting specific religions. Historical communities have argued that Biblical translations contain many translation errors and errata, and therefore that the use of biblical literalism in creation science is self-contradictory. == Kinds of creation science == === Biology === Creationist arguments in relation to biology center on an idea derived from Genesis that states that life was created by God, in a finite number of "created kinds," rather than through biological evolution from a common ancestor. Creationists contend that any observable speciation descends from these distinctly created kinds through inbreeding, deleterious mutations and other genetic mechanisms. Whereas evolutionary biologists and creationists share similar views of microevolution, creationists reject the fact that the process of macroevolution can explain common ancestry among organisms far beyond the level of common species. Creationists contend that there is no empirical evidence for new plant or animal species, and deny fossil evidence has ever been found documenting the process. Popular arguments against evolution have changed since the publishing of Henry M. Morris' first book on the subject, Scientific Creationism (1974), but some consistent themes remain: that missing links or gaps in the fossil record are proof against evolution; that the increased complexity of organisms over time through evolution is not possible due to the law of increasing entropy; that it is impossible that the mechanism of natural selection could account for common ancestry; and that evolutionary theory is untestable. The origin of the human species is particularly hotly contested; the fossil remains of hominid ancestors are not considered by advocates of creation biology to be evidence for a speciation event involving Homo sapiens. Creationists also assert that early hominids, are either apes, or humans. Richard Dawkins has explained evolution as "a theory of gradual, incremental change over millions of years, which starts with something very simple and works up along slow, gradual gradients to greater complexity," and described the existing fossil record as entirely consistent with that process. Biologists emphasize that transitional gaps between recovered fossils are to be expected, that the existence of any such gaps cannot be invoked to disprove evolution, and that instead the fossil evidence that could be used to disprove the theory would be those fossils which are found and which are entirely inconsistent with what can be predicted or anticipated by the evolutionary model. One example given by Dawkins was, "If there were a single hippo or rabbit in the Precambrian, that would completely blow evolution out of the water. None have ever been found." === Geology === ==== Flood geology ==== Flood geology is a concept based on the belief that most of Earth's geological record was formed by the Great Flood described in the story of Noah's Ark. Fossils and fossil fuels are believed to have formed from animal and plant matter which was buried rapidly during this flood, while submarine canyons are explained as having formed during a rapid runoff from the continents at the end of the flood. Sedimentary strata are also claimed to have been predominantly laid down during or after Noah's flood and orogeny. Flood geology is a variant of catastrophism and is contrasted with geological science in that it rejects standard geological principles such as uniformitarianism and radiometric dating. For example, the Creation Research Society argues that "uniformitarianism is wishful thinking." Geologists conclude that no evidence for such a flood is observed in the preserved rock layers and moreover that such a flood is physically impossible, given the current layout of land masses. For instance, since Mount Everest currently is approximately 8.8 kilometres in elevation and the Earth's surface area is 510,065,600 km2, the volume of water required to cover Mount Everest to a depth of 15 cubits (6.8 m), as indicated by Genesis 7:20, would be 4.6 billion cubic kilometres. Measurements of the amount of precipitable water vapor in the atmosphere have yielded results indicating that condensing all water vapor in a column of atmosphere would produce liquid water with a depth ranging between zero and approximately 70mm, depending on the date and the location of the column. Nevertheless, there continue to be adherents to the belief in flood geology, and in recent years new creationist models have been introduced such as catastrophic plate tectonics and catastrophic orogeny. ==== Radiometric dating ==== Creationists point to flawed experiments they have performed, which they claim demonstrate that 1.5 billion years of nuclear decay took place over a short period of time, from which they infer that "billion-fold speed-ups of nuclear decay" have occurred, a massive violation of the principle that radioisotope decay rates are constant, a core principle underlying nuclear physics generally, and radiometric dating in particular. The scientific community points to numerous flaws in the creationists' experiments, to the fact that their results have not been accepted for publication by any peer-reviewed scientific journal, and to the fact that the creationist scientists conducting them were untrained in experimental geochronology. They have also been criticised for widely publicising the results of their research as successful despite their own admission of insurmountable problems with their hypothesis. The constancy of the decay rates of isotopes is well supported in science. Evidence for this constancy includes the correspondences of date estimates taken from different radioactive isotopes as well as correspondences with non-radiometric dating techniques such as dendrochronology, ice core dating, and historical records. Although scientists have noted slight increases in the decay rate for isotopes subject to extreme pressures, those differences were too small to significantly impact date estimates. The constancy of the decay rates is also governed by first principles in quantum mechanics, wherein any deviation in the rate would require a change in the fundamental constants. According to these principles, a change in the fundamental constants could not influence different elements uniformly, and a comparison between each of the elements' resulting unique chronological timescales would then give inconsistent time estimates. In refutation of young Earth claims of inconstant decay rates affecting the reliability of radiometric dating, Roger C. Wiens, a physicist specializing in isotope dating states: There are only three quite technical instances where a half-life changes, and these do not affect the dating methods: "Only one technical exception occurs under terrestrial conditions, and this is not for an isotope used for dating. ... The artificially-produced isotope, beryllium-7 has been shown to change by up to 1.5%, depending on its chemical environment. ... Heavier atoms are even less subject to these minute changes, so the dates of rocks made by electron-capture decays would only be off by at most a few hundredths of a percent." "... Another case is material inside of stars, which is in a plasma state where electrons are not bound to atoms. In the extremely hot stellar environment, a completely different kind of decay can occur. 'Bound-state beta decay' occurs when the nucleus emits an electron into a bound electronic state close to the nucleus. ... All normal matter, such as everything on Earth, the Moon, meteorites, etc. has electrons in normal positions, so these instances never apply to rocks, or anything colder than several hundred thousand degrees." "The last case also involves very fast-moving matter. It has been demonstrated by atomic clocks in very fast spacecraft. These atomic clocks slow down very slightly (only a second or so per year) as predicted by Einstein's theory of relativity. No rocks in our solar system are going fast enough to make a noticeable change in their dates." ==== Radiohaloes ==== In the 1970s, young Earth creationist Robert V. Gentry proposed that radiohaloes in certain granites represented evidence for the Earth being created instantaneously rather than gradually. This idea has been criticized by physicists and geologists on many grounds including that the rocks Gentry studied were not primordial and that the radionuclides in question need not have been in the rocks initially. Thomas A. Baillieul, a geologist and retired senior environmental scientist with the United States Department of Energy, disputed Gentry's claims in an article entitled, "'Polonium Haloes' Refuted: A Review of 'Radioactive Halos in a Radio-Chronological and Cosmological Perspective' by Robert V. Gentry." Baillieul noted that Gentry was a physicist with no background in geology and given the absence of this background, Gentry had misrepresented the geological context from which the specimens were collected. Additionally, he noted that Gentry relied on research from the beginning of the 20th century, long before radioisotopes were thoroughly understood; that his assumption that a polonium isotope caused the rings was speculative; and that Gentry falsely argued that the half-life of radioactive elements varies with time. Gentry claimed that Baillieul could not publish his criticisms in a reputable scientific journal, although some of Baillieul's criticisms rested on work previously published in reputable scientific journals. === Astronomy and cosmology === ==== Creationist cosmologies ==== Several attempts have been made by creationists to construct a cosmology consistent with a young Universe rather than the standard cosmological age of the universe, based on the belief that Genesis describes the creation of the Universe as well as the Earth. The primary challenge for young-universe cosmologies is that the accepted distances in the Universe require millions or billions of years for light to travel to Earth (the "starlight problem"). An older creationist idea, proposed by creationist astronomer Barry Setterfield, is that the speed of light has decayed in the history of the Universe. More recently, creationist physicist Russell Humphreys has proposed a hypothesis called "white hole cosmology", asserting that the Universe expanded out of a white hole less than 10,000 years ago; claiming that the age of the universe is illusory and results from relativistic effects. Humphreys' cosmology is advocated by creationist organisations such as Answers in Genesis; however because its predictions conflict with current observations, it is not accepted by the scientific community. ==== Planetology ==== Various claims are made by creationists concerning alleged evidence that the age of the Solar System is of the order of thousands of years, in contrast to the scientifically accepted age of 4.6 billion years. It is commonly argued that the number of comets in the Solar System is much higher than would be expected given its supposed age. Young Earth Creationists reject the existence of the Kuiper belt and Oort cloud. They also argue that the recession of the Moon from the Earth is incompatible with either the Moon or the Earth being billions of years old. These claims have been refuted by planetologists. In response to increasing evidence suggesting that Mars once possessed a wetter climate, some creationists have proposed that the global flood affected not only the Earth but also Mars and other planets. People who support this claim include creationist astronomer Wayne Spencer and Russell Humphreys. An ongoing problem for creationists is the presence of impact craters on nearly all Solar System objects, which is consistent with scientific explanations of solar system origins but creates insuperable problems for young Earth claims. Creationists Harold Slusher and Richard Mandock, along with Glenn Morton (who later repudiated this claim) asserted that impact craters on the Moon are subject to rock flow, and so cannot be more than a few thousand years old. While some creationist astronomers assert that different phases of meteoritic bombardment of the Solar System occurred during "creation week" and during the subsequent Great Flood, others regard this as unsupported by the evidence and call for further research. == Groups == === Proponents === Answers in Genesis Creation Ministries International Creation Research Society Geoscience Research Institute Institute for Creation Research === Critics === American Museum of Natural History National Science Teachers Association National Center for Science Education No Answers in Genesis National Academy of Sciences Scientific American The BioLogos Foundation The Skeptic's Dictionary Talk.reason TalkOrigins Archive == See also == Conflict thesis Denialism Ken Ham Kent Hovind International Conference on Creationism Natural theology Omphalos hypothesis Adnan Oktar Jonathan Sarfati Scientific skepticism == References == == Bibliography == == Further reading == === Proponents === == External links == Notable creationist museums in the United States: Creation Evidence Museum, located in Glen Rose, Texas Creation Museum, located in Petersburg, Kentucky Human Timeline (Interactive) – Smithsonian, National Museum of Natural History (August 2016).
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No Science is an electronic music duo composed of Swedish producers and composers Johan Skugge and Jukka Rintamäki. They are best known for composing the soundtrack of the first-person shooter video games Battlefield 3 and Battlefield 4. == History == Jukka Rintamäki is an artist who has worked as a bassist, singer and songwriter of the band Silverbullit from Gothenburg. Johan Skugge was previously in the band Yvonne. The two formed the duo No Science in 2010 and used a combination of synth, drum machine and steel guitar. They have been working together since creating the music for the computer game Battlefield 3 in 2010. They also composed the soundtrack for the sequel, Battlefield 4. The duo's debut single as No Science, Magnificent Arp was released in late 2013. In February 2015 the single "Bits" was released featuring a remix by Swedish artist Jay-Jay Johanson. No Science's first album Lucky Resident was released in March 2015, and includes an appearance by El Perro del Mar. == Discography == === Albums === Lucky Resident (2015) === Singles === "Familiar Skies" (2015) "Bits" (2015) "Magnificent Arp" (2013) == References == == External links == Official website Official page at BLVVD jukkarintamaki.com
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Data science is an interdisciplinary academic field that uses statistics, scientific computing, scientific methods, processing, scientific visualization, algorithms and systems to extract or extrapolate knowledge from potentially noisy, structured, or unstructured data. Data science also integrates domain knowledge from the underlying application domain (e.g., natural sciences, information technology, and medicine). Data science is multifaceted and can be described as a science, a research paradigm, a research method, a discipline, a workflow, and a profession. Data science is "a concept to unify statistics, data analysis, informatics, and their related methods" to "understand and analyze actual phenomena" with data. It uses techniques and theories drawn from many fields within the context of mathematics, statistics, computer science, information science, and domain knowledge. However, data science is different from computer science and information science. Turing Award winner Jim Gray imagined data science as a "fourth paradigm" of science (empirical, theoretical, computational, and now data-driven) and asserted that "everything about science is changing because of the impact of information technology" and the data deluge. A data scientist is a professional who creates programming code and combines it with statistical knowledge to summarize data. == Foundations == Data science is an interdisciplinary field focused on extracting knowledge from typically large data sets and applying the knowledge from that data to solve problems in other application domains. The field encompasses preparing data for analysis, formulating data science problems, analyzing data, and summarizing these findings. As such, it incorporates skills from computer science, mathematics, data visualization, graphic design, communication, and business. Vasant Dhar writes that statistics emphasizes quantitative data and description. In contrast, data science deals with quantitative and qualitative data (e.g., from images, text, sensors, transactions, customer information, etc.) and emphasizes prediction and action. Andrew Gelman of Columbia University has described statistics as a non-essential part of data science. Stanford professor David Donoho writes that data science is not distinguished from statistics by the size of datasets or use of computing and that many graduate programs misleadingly advertise their analytics and statistics training as the essence of a data-science program. He describes data science as an applied field growing out of traditional statistics. == Etymology == === Early usage === In 1962, John Tukey described a field he called "data analysis", which resembles modern data science. In 1985, in a lecture given to the Chinese Academy of Sciences in Beijing, C. F. Jeff Wu used the term "data science" for the first time as an alternative name for statistics. Later, attendees at a 1992 statistics symposium at the University of Montpellier II acknowledged the emergence of a new discipline focused on data of various origins and forms, combining established concepts and principles of statistics and data analysis with computing. The term "data science" has been traced back to 1974, when Peter Naur proposed it as an alternative name to computer science. In 1996, the International Federation of Classification Societies became the first conference to specifically feature data science as a topic. However, the definition was still in flux. After the 1985 lecture at the Chinese Academy of Sciences in Beijing, in 1997 C. F. Jeff Wu again suggested that statistics should be renamed data science. He reasoned that a new name would help statistics shed inaccurate stereotypes, such as being synonymous with accounting or limited to describing data. In 1998, Hayashi Chikio argued for data science as a new, interdisciplinary concept, with three aspects: data design, collection, and analysis. === Modern usage === In 2012, technologists Thomas H. Davenport and DJ Patil declared "Data Scientist: The Sexiest Job of the 21st Century", a catchphrase that was picked up even by major-city newspapers like the New York Times and the Boston Globe. A decade later, they reaffirmed it, stating that "the job is more in demand than ever with employers". The modern conception of data science as an independent discipline is sometimes attributed to William S. Cleveland. In 2014, the American Statistical Association's Section on Statistical Learning and Data Mining changed its name to the Section on Statistical Learning and Data Science, reflecting the ascendant popularity of data science. The professional title of "data scientist" has been attributed to DJ Patil and Jeff Hammerbacher in 2008. Though it was used by the National Science Board in their 2005 report "Long-Lived Digital Data Collections: Enabling Research and Education in the 21st Century", it referred broadly to any key role in managing a digital data collection. == Data science and data analysis == Data analysis typically involves working with structured datasets to answer specific questions or solve specific problems. This can involve tasks such as data cleaning and data visualization to summarize data and develop hypotheses about relationships between variables. Data analysts typically use statistical methods to test these hypotheses and draw conclusions from the data. Data science involves working with larger datasets that often require advanced computational and statistical methods to analyze. Data scientists often work with unstructured data such as text or images and use machine learning algorithms to build predictive models. Data science often uses statistical analysis, data preprocessing, and supervised learning. == Cloud computing for data science == Cloud computing can offer access to large amounts of computational power and storage. In big data, where volumes of information are continually generated and processed, these platforms can be used to handle complex and resource-intensive analytical tasks. Some distributed computing frameworks are designed to handle big data workloads. These frameworks can enable data scientists to process and analyze large datasets in parallel, which can reduce processing times. == Ethical consideration in data science == Data science involves collecting, processing, and analyzing data which often includes personal and sensitive information. Ethical concerns include potential privacy violations, bias perpetuation, and negative societal impacts. Machine learning models can amplify existing biases present in training data, leading to discriminatory or unfair outcomes. == See also == Python (programming language) R (programming language) Data engineering Big data Machine learning Bioinformatics Astroinformatics Topological data analysis List of open-source data science software == References ==
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https://en.wikipedia.org/wiki/Data_science
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Medicine is the science and practice of caring for patients, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Contemporary medicine applies biomedical sciences, biomedical research, genetics, and medical technology to diagnose, treat, and prevent injury and disease, typically through pharmaceuticals or surgery, but also through therapies as diverse as psychotherapy, external splints and traction, medical devices, biologics, and ionizing radiation, amongst others. Medicine has been practiced since prehistoric times, and for most of this time it was an art (an area of creativity and skill), frequently having connections to the religious and philosophical beliefs of local culture. For example, a medicine man would apply herbs and say prayers for healing, or an ancient philosopher and physician would apply bloodletting according to the theories of humorism. In recent centuries, since the advent of modern science, most medicine has become a combination of art and science (both basic and applied, under the umbrella of medical science). For example, while stitching technique for sutures is an art learned through practice, knowledge of what happens at the cellular and molecular level in the tissues being stitched arises through science. Prescientific forms of medicine, now known as traditional medicine or folk medicine, remain commonly used in the absence of scientific medicine and are thus called alternative medicine. Alternative treatments outside of scientific medicine with ethical, safety and efficacy concerns are termed quackery. == Etymology == Medicine (UK: , US: ) is the science and practice of the diagnosis, prognosis, treatment, and prevention of disease. The word "medicine" is derived from Latin medicus, meaning "a physician". The word "physic" itself, from which "physician" derives, was the old word for what is now called a medicine, and also the field of medicine. == Clinical practice == Medical availability and clinical practice vary across the world due to regional differences in culture and technology. Modern scientific medicine is highly developed in the Western world, while in developing countries such as parts of Africa or Asia, the population may rely more heavily on traditional medicine with limited evidence and efficacy and no required formal training for practitioners. In the developed world, evidence-based medicine is not universally used in clinical practice; for example, a 2007 survey of literature reviews found that about 49% of the interventions lacked sufficient evidence to support either benefit or harm. In modern clinical practice, physicians and physician assistants personally assess patients to diagnose, prognose, treat, and prevent disease using clinical judgment. The doctor-patient relationship typically begins with an interaction with an examination of the patient's medical history and medical record, followed by a medical interview and a physical examination. Basic diagnostic medical devices (e.g., stethoscope, tongue depressor) are typically used. After examining for signs and interviewing for symptoms, the doctor may order medical tests (e.g., blood tests), take a biopsy, or prescribe pharmaceutical drugs or other therapies. Differential diagnosis methods help to rule out conditions based on the information provided. During the encounter, properly informing the patient of all relevant facts is an important part of the relationship and the development of trust. The medical encounter is then documented in the medical record, which is a legal document in many jurisdictions. Follow-ups may be shorter but follow the same general procedure, and specialists follow a similar process. The diagnosis and treatment may take only a few minutes or a few weeks, depending on the complexity of the issue. The components of the medical interview and encounter are: Chief complaint (CC): the reason for the current medical visit. These are the symptoms. They are in the patient's own words and are recorded along with the duration of each one. Also called chief concern or presenting complaint. Current activity: occupation, hobbies, what the patient actually does. Family history (FH): listing of diseases in the family that may impact the patient. A family tree is sometimes used. History of present illness (HPI): the chronological order of events of symptoms and further clarification of each symptom. Distinguishable from history of previous illness, often called past medical history (PMH). Medical history comprises HPI and PMH. Medications (Rx): what drugs the patient takes including prescribed, over-the-counter, and home remedies, as well as alternative and herbal medicines or remedies. Allergies are also recorded. Past medical history (PMH/PMHx): concurrent medical problems, past hospitalizations and operations, injuries, past infectious diseases or vaccinations, history of known allergies. Review of systems (ROS) or systems inquiry: a set of additional questions to ask, which may be missed on HPI: a general enquiry (have you noticed any weight loss, change in sleep quality, fevers, lumps and bumps? etc.), followed by questions on the body's main organ systems (heart, lungs, digestive tract, urinary tract, etc.). Social history (SH): birthplace, residences, marital history, social and economic status, habits (including diet, medications, tobacco, alcohol). The physical examination is the examination of the patient for medical signs of disease that are objective and observable, in contrast to symptoms that are volunteered by the patient and are not necessarily objectively observable. The healthcare provider uses sight, hearing, touch, and sometimes smell (e.g., in infection, uremia, diabetic ketoacidosis). Four actions are the basis of physical examination: inspection, palpation (feel), percussion (tap to determine resonance characteristics), and auscultation (listen), generally in that order, although auscultation occurs prior to percussion and palpation for abdominal assessments. The clinical examination involves the study of: Abdomen and rectum Cardiovascular (heart and blood vessels) General appearance of the patient and specific indicators of disease (nutritional status, presence of jaundice, pallor or clubbing) Genitalia (and pregnancy if the patient is or could be pregnant) Head, eye, ear, nose, and throat (HEENT) Musculoskeletal (including spine and extremities) Neurological (consciousness, awareness, brain, vision, cranial nerves, spinal cord and peripheral nerves) Psychiatric (orientation, mental state, mood, evidence of abnormal perception or thought). Respiratory (large airways and lungs) Skin Vital signs including height, weight, body temperature, blood pressure, pulse, respiration rate, and hemoglobin oxygen saturation It is to likely focus on areas of interest highlighted in the medical history and may not include everything listed above. The treatment plan may include ordering additional medical laboratory tests and medical imaging studies, starting therapy, referral to a specialist, or watchful observation. A follow-up may be advised. Depending upon the health insurance plan and the managed care system, various forms of "utilization review", such as prior authorization of tests, may place barriers on accessing expensive services. The medical decision-making (MDM) process includes the analysis and synthesis of all the above data to come up with a list of possible diagnoses (the differential diagnoses), along with an idea of what needs to be done to obtain a definitive diagnosis that would explain the patient's problem. On subsequent visits, the process may be repeated in an abbreviated manner to obtain any new history, symptoms, physical findings, lab or imaging results, or specialist consultations. == Institutions == Contemporary medicine is, in general, conducted within health care systems. Legal, credentialing, and financing frameworks are established by individual governments, augmented on occasion by international organizations, such as churches. The characteristics of any given health care system have a significant impact on the way medical care is provided. From ancient times, Christian emphasis on practical charity gave rise to the development of systematic nursing and hospitals, and the Catholic Church today remains the largest non-government provider of medical services in the world. Advanced industrial countries (with the exception of the United States) and many developing countries provide medical services through a system of universal health care that aims to guarantee care for all through a single-payer health care system or compulsory private or cooperative health insurance. This is intended to ensure that the entire population has access to medical care on the basis of need rather than ability to pay. Delivery may be via private medical practices, state-owned hospitals and clinics, or charities, most commonly a combination of all three. Most tribal societies provide no guarantee of healthcare for the population as a whole. In such societies, healthcare is available to those who can afford to pay for it, have self-insured it (either directly or as part of an employment contract), or may be covered by care financed directly by the government or tribe. Transparency of information is another factor defining a delivery system. Access to information on conditions, treatments, quality, and pricing greatly affects the choice of patients/consumers and, therefore, the incentives of medical professionals. While the US healthcare system has come under fire for its lack of openness, new legislation may encourage greater openness. There is a perceived tension between the need for transparency on the one hand and such issues as patient confidentiality and the possible exploitation of information for commercial gain on the other. The health professionals who provide care in medicine comprise multiple professions, such as medics, nurses, physiotherapists, and psychologists. These professions will have their own ethical standards, professional education, and bodies. The medical profession has been conceptualized from a sociological perspective. === Delivery === Provision of medical care is classified into primary, secondary, and tertiary care categories. Primary care medical services are provided by physicians, physician assistants, nurse practitioners, or other health professionals who have first contact with a patient seeking medical treatment or care. These occur in physician offices, clinics, nursing homes, schools, home visits, and other places close to patients. About 90% of medical visits can be treated by the primary care provider. These include treatment of acute and chronic illnesses, preventive care and health education for all ages and both sexes. Secondary care medical services are provided by medical specialists in their offices or clinics or at local community hospitals for a patient referred by a primary care provider who first diagnosed or treated the patient. Referrals are made for those patients who required the expertise or procedures performed by specialists. These include both ambulatory care and inpatient services, emergency departments, intensive care medicine, surgery services, physical therapy, labor and delivery, endoscopy units, diagnostic laboratory and medical imaging services, hospice centers, etc. Some primary care providers may also take care of hospitalized patients and deliver babies in a secondary care setting. Tertiary care medical services are provided by specialist hospitals or regional centers equipped with diagnostic and treatment facilities not generally available at local hospitals. These include trauma centers, burn treatment centers, advanced neonatology unit services, organ transplants, high-risk pregnancy, radiation oncology, etc. Modern medical care also depends on information – still delivered in many health care settings on paper records, but increasingly nowadays by electronic means. In low-income countries, modern healthcare is often too expensive for the average person. International healthcare policy researchers have advocated that "user fees" be removed in these areas to ensure access, although even after removal, significant costs and barriers remain. Separation of prescribing and dispensing is a practice in medicine and pharmacy in which the physician who provides a medical prescription is independent from the pharmacist who provides the prescription drug. In the Western world there are centuries of tradition for separating pharmacists from physicians. In Asian countries, it is traditional for physicians to also provide drugs. == Branches == Working together as an interdisciplinary team, many highly trained health professionals besides medical practitioners are involved in the delivery of modern health care. Examples include: nurses, emergency medical technicians and paramedics, laboratory scientists, pharmacists, podiatrists, physiotherapists, respiratory therapists, speech therapists, occupational therapists, radiographers, dietitians, and bioengineers, medical physicists, surgeons, surgeon's assistant, surgical technologist. The scope and sciences underpinning human medicine overlap many other fields. A patient admitted to the hospital is usually under the care of a specific team based on their main presenting problem, e.g., the cardiology team, who then may interact with other specialties, e.g., surgical, radiology, to help diagnose or treat the main problem or any subsequent complications/developments. Physicians have many specializations and subspecializations into certain branches of medicine, which are listed below. There are variations from country to country regarding which specialties certain subspecialties are in. The main branches of medicine are: Basic sciences of medicine; this is what every physician is educated in, and some return to in biomedical research. Interdisciplinary fields, where different medical specialties are mixed to function in certain occasions. Medical specialties === Basic sciences === Anatomy is the study of the physical structure of organisms. In contrast to macroscopic or gross anatomy, cytology and histology are concerned with microscopic structures. Biochemistry is the study of the chemistry taking place in living organisms, especially the structure and function of their chemical components. Biomechanics is the study of the structure and function of biological systems by means of the methods of Mechanics. Biophysics is an interdisciplinary science that uses the methods of physics and physical chemistry to study biological systems. Biostatistics is the application of statistics to biological fields in the broadest sense. A knowledge of biostatistics is essential in the planning, evaluation, and interpretation of medical research. It is also fundamental to epidemiology and evidence-based medicine. Cytology is the microscopic study of individual cells. Embryology is the study of the early development of organisms. Endocrinology is the study of hormones and their effect throughout the body of animals. Epidemiology is the study of the demographics of disease processes, and includes, but is not limited to, the study of epidemics. Genetics is the study of genes, and their role in biological inheritance. Gynecology is the study of female reproductive system. Histology is the study of the structures of biological tissues by light microscopy, electron microscopy and immunohistochemistry. Immunology is the study of the immune system, which includes the innate and adaptive immune system in humans, for example. Lifestyle medicine is the study of the chronic conditions, and how to prevent, treat and reverse them. Medical physics is the study of the applications of physics principles in medicine. Microbiology is the study of microorganisms, including protozoa, bacteria, fungi, and viruses. Molecular biology is the study of molecular underpinnings of the process of replication, transcription and translation of the genetic material. Neuroscience includes those disciplines of science that are related to the study of the nervous system. A main focus of neuroscience is the biology and physiology of the human brain and spinal cord. Some related clinical specialties include neurology, neurosurgery and psychiatry. Nutrition science (theoretical focus) and dietetics (practical focus) is the study of the relationship of food and drink to health and disease, especially in determining an optimal diet. Medical nutrition therapy is done by dietitians and is prescribed for diabetes, cardiovascular diseases, weight and eating disorders, allergies, malnutrition, and neoplastic diseases. Pathology as a science is the study of disease – the causes, course, progression and resolution thereof. Pharmacology is the study of drugs and their actions. Photobiology is the study of the interactions between non-ionizing radiation and living organisms. Physiology is the study of the normal functioning of the body and the underlying regulatory mechanisms. Radiobiology is the study of the interactions between ionizing radiation and living organisms. Toxicology is the study of hazardous effects of drugs and poisons. === Specialties === In the broadest meaning of "medicine", there are many different specialties. In the UK, most specialities have their own body or college, which has its own entrance examination. These are collectively known as the Royal Colleges, although not all currently use the term "Royal". The development of a speciality is often driven by new technology (such as the development of effective anaesthetics) or ways of working (such as emergency departments); the new specialty leads to the formation of a unifying body of doctors and the prestige of administering their own examination. Within medical circles, specialities usually fit into one of two broad categories: "Medicine" and "Surgery". "Medicine" refers to the practice of non-operative medicine, and most of its subspecialties require preliminary training in Internal Medicine. In the UK, this was traditionally evidenced by passing the examination for the Membership of the Royal College of Physicians (MRCP) or the equivalent college in Scotland or Ireland. "Surgery" refers to the practice of operative medicine, and most subspecialties in this area require preliminary training in General Surgery, which in the UK leads to membership of the Royal College of Surgeons of England (MRCS). At present, some specialties of medicine do not fit easily into either of these categories, such as radiology, pathology, or anesthesia. Most of these have branched from one or other of the two camps above; for example anaesthesia developed first as a faculty of the Royal College of Surgeons (for which MRCS/FRCS would have been required) before becoming the Royal College of Anaesthetists and membership of the college is attained by sitting for the examination of the Fellowship of the Royal College of Anesthetists (FRCA). ==== Surgical specialty ==== Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate or treat a pathological condition such as disease or injury, to help improve bodily function or appearance or to repair unwanted ruptured areas (for example, a perforated ear drum). Surgeons must also manage pre-operative, post-operative, and potential surgical candidates on the hospital wards. In some centers, anesthesiology is part of the division of surgery (for historical and logistical reasons), although it is not a surgical discipline. Other medical specialties may employ surgical procedures, such as ophthalmology and dermatology, but are not considered surgical sub-specialties per se. Surgical training in the U.S. requires a minimum of five years of residency after medical school. Sub-specialties of surgery often require seven or more years. In addition, fellowships can last an additional one to three years. Because post-residency fellowships can be competitive, many trainees devote two additional years to research. Thus in some cases surgical training will not finish until more than a decade after medical school. Furthermore, surgical training can be very difficult and time-consuming. Surgical subspecialties include those a physician may specialize in after undergoing general surgery residency training as well as several surgical fields with separate residency training. Surgical subspecialties that one may pursue following general surgery residency training: Bariatric surgery Cardiovascular surgery – may also be pursued through a separate cardiovascular surgery residency track Colorectal surgery Endocrine surgery General surgery Hand surgery Hepatico-Pancreatico-Biliary Surgery Minimally invasive surgery Pediatric surgery Plastic surgery – may also be pursued through a separate plastic surgery residency track Surgical critical care Surgical oncology Transplant surgery Trauma surgery Vascular surgery – may also be pursued through a separate vascular surgery residency track Other surgical specialties within medicine with their own individual residency training: Dermatology Neurosurgery Ophthalmology Oral and maxillofacial surgery Orthopedic surgery Otorhinolaryngology Podiatric surgery – do not undergo medical school training, but rather separate training in podiatry school Urology ==== Internal medicine specialty ==== Internal medicine is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. According to some sources, an emphasis on internal structures is implied. In North America, specialists in internal medicine are commonly called "internists". Elsewhere, especially in Commonwealth nations, such specialists are often called physicians. These terms, internist or physician (in the narrow sense, common outside North America), generally exclude practitioners of gynecology and obstetrics, pathology, psychiatry, and especially surgery and its subspecialities. Because their patients are often seriously ill or require complex investigations, internists do much of their work in hospitals. Formerly, many internists were not subspecialized; such general physicians would see any complex nonsurgical problem; this style of practice has become much less common. In modern urban practice, most internists are subspecialists: that is, they generally limit their medical practice to problems of one organ system or to one particular area of medical knowledge. For example, gastroenterologists and nephrologists specialize respectively in diseases of the gut and the kidneys. In the Commonwealth of Nations and some other countries, specialist pediatricians and geriatricians are also described as specialist physicians (or internists) who have subspecialized by age of patient rather than by organ system. Elsewhere, especially in North America, general pediatrics is often a form of primary care. There are many subspecialities (or subdisciplines) of internal medicine: Training in internal medicine (as opposed to surgical training), varies considerably across the world: see the articles on medical education for more details. In North America, it requires at least three years of residency training after medical school, which can then be followed by a one- to three-year fellowship in the subspecialties listed above. In general, resident work hours in medicine are less than those in surgery, averaging about 60 hours per week in the US. This difference does not apply in the UK where all doctors are now required by law to work less than 48 hours per week on average. ==== Diagnostic specialties ==== Clinical laboratory sciences are the clinical diagnostic services that apply laboratory techniques to diagnosis and management of patients. In the United States, these services are supervised by a pathologist. The personnel that work in these medical laboratory departments are technically trained staff who do not hold medical degrees, but who usually hold an undergraduate medical technology degree, who actually perform the tests, assays, and procedures needed for providing the specific services. Subspecialties include transfusion medicine, cellular pathology, clinical chemistry, hematology, clinical microbiology and clinical immunology. Clinical neurophysiology is concerned with testing the physiology or function of the central and peripheral aspects of the nervous system. These kinds of tests can be divided into recordings of: (1) spontaneous or continuously running electrical activity, or (2) stimulus evoked responses. Subspecialties include electroencephalography, electromyography, evoked potential, nerve conduction study and polysomnography. Sometimes these tests are performed by techs without a medical degree, but the interpretation of these tests is done by a medical professional. Diagnostic radiology is concerned with imaging of the body, e.g. by x-rays, x-ray computed tomography, ultrasonography, and nuclear magnetic resonance tomography. Interventional radiologists can access areas in the body under imaging for an intervention or diagnostic sampling. Nuclear medicine is concerned with studying human organ systems by administering radiolabelled substances (radiopharmaceuticals) to the body, which can then be imaged outside the body by a gamma camera or a PET scanner. Each radiopharmaceutical consists of two parts: a tracer that is specific for the function under study (e.g., neurotransmitter pathway, metabolic pathway, blood flow, or other), and a radionuclide (usually either a gamma-emitter or a positron emitter). There is a degree of overlap between nuclear medicine and radiology, as evidenced by the emergence of combined devices such as the PET/CT scanner. Pathology as a medical specialty is the branch of medicine that deals with the study of diseases and the morphologic, physiologic changes produced by them. As a diagnostic specialty, pathology can be considered the basis of modern scientific medical knowledge and plays a large role in evidence-based medicine. Many modern molecular tests such as flow cytometry, polymerase chain reaction (PCR), immunohistochemistry, cytogenetics, gene rearrangements studies and fluorescent in situ hybridization (FISH) fall within the territory of pathology. ==== Other major specialties ==== The following are some major medical specialties that do not directly fit into any of the above-mentioned groups: Anesthesiology (also known as anaesthetics): concerned with the perioperative management of the surgical patient. The anesthesiologist's role during surgery is to prevent derangement in the vital organs' (i.e. brain, heart, kidneys) functions and postoperative pain. Outside of the operating room, the anesthesiology physician also serves the same function in the labor and delivery ward, and some are specialized in critical medicine. Emergency medicine is concerned with the diagnosis and treatment of acute or life-threatening conditions, including trauma, surgical, medical, pediatric, and psychiatric emergencies. Family medicine, family practice, general practice or primary care is, in many countries, the first port-of-call for patients with non-emergency medical problems. Family physicians often provide services across a broad range of settings including office based practices, emergency department coverage, inpatient care, and nursing home care. Medical genetics is concerned with the diagnosis and management of hereditary disorders. Neurology is concerned with diseases of the nervous system. In the UK, neurology is a subspecialty of general medicine. Obstetrics and gynecology (often abbreviated as OB/GYN (American English) or Obs & Gynae (British English)) are concerned respectively with childbirth and the female reproductive and associated organs. Reproductive medicine and fertility medicine are generally practiced by gynecological specialists. Pediatrics (AE) or paediatrics (BE) is devoted to the care of infants, children, and adolescents. Like internal medicine, there are many pediatric subspecialties for specific age ranges, organ systems, disease classes, and sites of care delivery. Pharmaceutical medicine is the medical scientific discipline concerned with the discovery, development, evaluation, registration, monitoring and medical aspects of marketing of medicines for the benefit of patients and public health. Physical medicine and rehabilitation (or physiatry) is concerned with functional improvement after injury, illness, or congenital disorders. Podiatric medicine is the study of, diagnosis, and medical and surgical treatment of disorders of the foot, ankle, lower limb, hip and lower back. Preventive medicine is the branch of medicine concerned with preventing disease. Community health or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis. Psychiatry is the branch of medicine concerned with the bio-psycho-social study of the etiology, diagnosis, treatment and prevention of cognitive, perceptual, emotional and behavioral disorders. Related fields include psychotherapy and clinical psychology. === Interdisciplinary fields === Some interdisciplinary sub-specialties of medicine include: Addiction medicine deals with the treatment of addiction. Aerospace medicine deals with medical problems related to flying and space travel. Biomedical Engineering is a field dealing with the application of engineering principles to medical practice. Clinical pharmacology is concerned with how systems of therapeutics interact with patients. Conservation medicine studies the relationship between human and non-human animal health, and environmental conditions. Also known as ecological medicine, environmental medicine, or medical geology. Disaster medicine deals with medical aspects of emergency preparedness, disaster mitigation and management. Diving medicine (or hyperbaric medicine) is the prevention and treatment of diving-related problems. Evolutionary medicine is a perspective on medicine derived through applying evolutionary theory. Forensic medicine deals with medical questions in legal context, such as determination of the time and cause of death, type of weapon used to inflict trauma, reconstruction of the facial features using remains of deceased (skull) thus aiding identification. Gender-based medicine studies the biological and physiological differences between the human sexes and how that affects differences in disease. Health informatics is a relatively recent field that deal with the application of computers and information technology to medicine. Hospice and Palliative Medicine is a relatively modern branch of clinical medicine that deals with pain and symptom relief and emotional support in patients with terminal illnesses including cancer and heart failure. Hospital medicine is the general medical care of hospitalized patients. Physicians whose primary professional focus is hospital medicine are called hospitalists in the United States and Canada. The term Most Responsible Physician (MRP) or attending physician is also used interchangeably to describe this role. Laser medicine involves the use of lasers in the diagnostics or treatment of various conditions. Many other health science fields, e.g. dietetics Medical ethics deals with ethical and moral principles that apply values and judgments to the practice of medicine. Medical humanities includes the humanities (literature, philosophy, ethics, history and religion), social science (anthropology, cultural studies, psychology, sociology), and the arts (literature, theater, film, and visual arts) and their application to medical education and practice. Nosokinetics is the science/subject of measuring and modelling the process of care in health and social care systems. Nosology is the classification of diseases for various purposes. Occupational medicine is the provision of health advice to organizations and individuals to ensure that the highest standards of health and safety at work can be achieved and maintained. Pain management (also called pain medicine, or algiatry) is the medical discipline concerned with the relief of pain. Pharmacogenomics is a form of individualized medicine. Podiatric medicine is the study of, diagnosis, and medical treatment of disorders of the foot, ankle, lower limb, hip and lower back. Sexual medicine is concerned with diagnosing, assessing and treating all disorders related to sexuality. Sports medicine deals with the treatment and prevention and rehabilitation of sports/exercise injuries such as muscle spasms, muscle tears, injuries to ligaments (ligament tears or ruptures) and their repair in athletes, amateur and professional. Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be used to treat disease and promote health. Travel medicine or emporiatrics deals with health problems of international travelers or travelers across highly different environments. Tropical medicine deals with the prevention and treatment of tropical diseases. It is studied separately in temperate climates where those diseases are quite unfamiliar to medical practitioners and their local clinical needs. Urgent care focuses on delivery of unscheduled, walk-in care outside of the hospital emergency department for injuries and illnesses that are not severe enough to require care in an emergency department. In some jurisdictions this function is combined with the emergency department. Veterinary medicine; veterinarians apply similar techniques as physicians to the care of non-human animals. Wilderness medicine entails the practice of medicine in the wild, where conventional medical facilities may not be available. == Education and legal controls == Medical education and training varies around the world. It typically involves entry level education at a university medical school, followed by a period of supervised practice or internship, or residency. This can be followed by postgraduate vocational training. A variety of teaching methods have been employed in medical education, still itself a focus of active research. In Canada and the United States of America, a Doctor of Medicine degree, often abbreviated M.D., or a Doctor of Osteopathic Medicine degree, often abbreviated as D.O. and unique to the United States, must be completed in and delivered from a recognized university. Since knowledge, techniques, and medical technology continue to evolve at a rapid rate, many regulatory authorities require continuing medical education. Medical practitioners upgrade their knowledge in various ways, including medical journals, seminars, conferences, and online programs. A database of objectives covering medical knowledge, as suggested by national societies across the United States, can be searched at http://data.medobjectives.marian.edu/ Archived 4 October 2018 at the Wayback Machine. In most countries, it is a legal requirement for a medical doctor to be licensed or registered. In general, this entails a medical degree from a university and accreditation by a medical board or an equivalent national organization, which may ask the applicant to pass exams. This restricts the considerable legal authority of the medical profession to physicians that are trained and qualified by national standards. It is also intended as an assurance to patients and as a safeguard against charlatans that practice inadequate medicine for personal gain. While the laws generally require medical doctors to be trained in "evidence based", Western, or Hippocratic Medicine, they are not intended to discourage different paradigms of health. In the European Union, the profession of doctor of medicine is regulated. A profession is said to be regulated when access and exercise is subject to the possession of a specific professional qualification. The regulated professions database contains a list of regulated professions for doctor of medicine in the EU member states, EEA countries and Switzerland. This list is covered by the Directive 2005/36/EC. Doctors who are negligent or intentionally harmful in their care of patients can face charges of medical malpractice and be subject to civil, criminal, or professional sanctions. == Medical ethics == Medical ethics is a system of moral principles that apply values and judgments to the practice of medicine. As a scholarly discipline, medical ethics encompasses its practical application in clinical settings as well as work on its history, philosophy, theology, and sociology. Six of the values that commonly apply to medical ethics discussions are: autonomy – the patient has the right to refuse or choose their treatment. (Latin: Voluntas aegroti suprema lex.) beneficence – a practitioner should act in the best interest of the patient. (Latin: Salus aegroti suprema lex.) justice – concerns the distribution of scarce health resources, and the decision of who gets what treatment (fairness and equality). non-maleficence – "first, do no harm" (Latin: primum non-nocere). respect for persons – the patient (and the person treating the patient) have the right to be treated with dignity. truthfulness and honesty – the concept of informed consent has increased in importance since the historical events of the Doctors' Trial of the Nuremberg trials, Tuskegee syphilis experiment, and others. Values such as these do not give answers as to how to handle a particular situation, but provide a useful framework for understanding conflicts. When moral values are in conflict, the result may be an ethical dilemma or crisis. Sometimes, no good solution to a dilemma in medical ethics exists, and occasionally, the values of the medical community (i.e., the hospital and its staff) conflict with the values of the individual patient, family, or larger non-medical community. Conflicts can also arise between health care providers, or among family members. For example, some argue that the principles of autonomy and beneficence clash when patients refuse blood transfusions, considering them life-saving; and truth-telling was not emphasized to a large extent before the HIV era. == History == === Ancient world === Prehistoric medicine incorporated plants (herbalism), animal parts, and minerals. In many cases these materials were used ritually as magical substances by priests, shamans, or medicine men. Well-known spiritual systems include animism (the notion of inanimate objects having spirits), spiritualism (an appeal to gods or communion with ancestor spirits); shamanism (the vesting of an individual with mystic powers); and divination (magically obtaining the truth). The field of medical anthropology examines the ways in which culture and society are organized around or impacted by issues of health, health care and related issues. The earliest known medical texts in the world were found in the ancient Syrian city of Ebla and date back to 2500 BCE. Other early records on medicine have been discovered from ancient Egyptian medicine, Babylonian Medicine, Ayurvedic medicine (in the Indian subcontinent), classical Chinese medicine (Alternative medicine) predecessor to the modern traditional Chinese medicine), and ancient Greek medicine and Roman medicine. In Egypt, Imhotep (3rd millennium BCE) is the first physician in history known by name. The oldest Egyptian medical text is the Kahun Gynaecological Papyrus from around 2000 BCE, which describes gynaecological diseases. The Edwin Smith Papyrus dating back to 1600 BCE is an early work on surgery, while the Ebers Papyrus dating back to 1500 BCE is akin to a textbook on medicine. In China, archaeological evidence of medicine in Chinese dates back to the Bronze Age Shang dynasty, based on seeds for herbalism and tools presumed to have been used for surgery. The Huangdi Neijing, the progenitor of Chinese medicine, is a medical text written beginning in the 2nd century BCE and compiled in the 3rd century. In India, the surgeon Sushruta described numerous surgical operations, including the earliest forms of plastic surgery.Earliest records of dedicated hospitals come from Mihintale in Sri Lanka where evidence of dedicated medicinal treatment facilities for patients are found. In Greece, the ancient Greek physician Hippocrates, the "father of modern medicine", laid the foundation for a rational approach to medicine. Hippocrates introduced the Hippocratic Oath for physicians, which is still relevant and in use today, and was the first to categorize illnesses as acute, chronic, endemic and epidemic, and use terms such as, "exacerbation, relapse, resolution, crisis, paroxysm, peak, and convalescence". The Greek physician Galen was also one of the greatest surgeons of the ancient world and performed many audacious operations, including brain and eye surgeries. After the fall of the Western Roman Empire and the onset of the Early Middle Ages, the Greek tradition of medicine went into decline in Western Europe, although it continued uninterrupted in the Eastern Roman (Byzantine) Empire. Most of our knowledge of ancient Hebrew medicine during the 1st millennium BC comes from the Torah, i.e. the Five Books of Moses, which contain various health related laws and rituals. The Hebrew contribution to the development of modern medicine started in the Byzantine Era, with the physician Asaph the Jew. === Middle Ages === The concept of hospital as institution to offer medical care and possibility of a cure for the patients due to the ideals of Christian charity, rather than just merely a place to die, appeared in the Byzantine Empire. Although the concept of uroscopy was known to Galen, he did not see the importance of using it to localize the disease. It was under the Byzantines with physicians such of Theophilus Protospatharius that they realized the potential in uroscopy to determine disease in a time when no microscope or stethoscope existed. That practice eventually spread to the rest of Europe. After 750 CE, the Muslim world had the works of Hippocrates, Galen and Sushruta translated into Arabic, and Islamic physicians engaged in some significant medical research. Notable Islamic medical pioneers include the Persian polymath, Avicenna, who, along with Imhotep and Hippocrates, has also been called the "father of medicine". He wrote The Canon of Medicine which became a standard medical text at many medieval European universities, considered one of the most famous books in the history of medicine. Others include Abulcasis, Avenzoar, Ibn al-Nafis, and Averroes. Persian physician Rhazes was one of the first to question the Greek theory of humorism, which nevertheless remained influential in both medieval Western and medieval Islamic medicine. Some volumes of Rhazes's work Al-Mansuri, namely "On Surgery" and "A General Book on Therapy", became part of the medical curriculum in European universities. Additionally, he has been described as a doctor's doctor, the father of pediatrics, and a pioneer of ophthalmology. For example, he was the first to recognize the reaction of the eye's pupil to light. The Persian Bimaristan hospitals were an early example of public hospitals. In Europe, Charlemagne decreed that a hospital should be attached to each cathedral and monastery and the historian Geoffrey Blainey likened the activities of the Catholic Church in health care during the Middle Ages to an early version of a welfare state: "It conducted hospitals for the old and orphanages for the young; hospices for the sick of all ages; places for the lepers; and hostels or inns where pilgrims could buy a cheap bed and meal". It supplied food to the population during famine and distributed food to the poor. This welfare system the church funded through collecting taxes on a large scale and possessing large farmlands and estates. The Benedictine order was noted for setting up hospitals and infirmaries in their monasteries, growing medical herbs and becoming the chief medical care givers of their districts, as at the great Abbey of Cluny. The Church also established a network of cathedral schools and universities where medicine was studied. The Schola Medica Salernitana in Salerno, looking to the learning of Greek and Arab physicians, grew to be the finest medical school in medieval Europe. However, the fourteenth and fifteenth century Black Death devastated both the Middle East and Europe, and it has even been argued that Western Europe was generally more effective in recovering from the pandemic than the Middle East. In the early modern period, important early figures in medicine and anatomy emerged in Europe, including Gabriele Falloppio and William Harvey. The major shift in medical thinking was the gradual rejection, especially during the Black Death in the 14th and 15th centuries, of what may be called the "traditional authority" approach to science and medicine. This was the notion that because some prominent person in the past said something must be so, then that was the way it was, and anything one observed to the contrary was an anomaly (which was paralleled by a similar shift in European society in general – see Copernicus's rejection of Ptolemy's theories on astronomy). Physicians like Vesalius improved upon or disproved some of the theories from the past. The main tomes used both by medicine students and expert physicians were Materia Medica and Pharmacopoeia. Andreas Vesalius was the author of De humani corporis fabrica, an important book on human anatomy. Bacteria and microorganisms were first observed with a microscope by Antonie van Leeuwenhoek in 1676, initiating the scientific field microbiology. Independently from Ibn al-Nafis, Michael Servetus rediscovered the pulmonary circulation, but this discovery did not reach the public because it was written down for the first time in the "Manuscript of Paris" in 1546, and later published in the theological work for which he paid with his life in 1553. Later this was described by Renaldus Columbus and Andrea Cesalpino. Herman Boerhaave is sometimes referred to as a "father of physiology" due to his exemplary teaching in Leiden and textbook 'Institutiones medicae' (1708). Pierre Fauchard has been called "the father of modern dentistry". === Modern === Veterinary medicine was, for the first time, truly separated from human medicine in 1761, when the French veterinarian Claude Bourgelat founded the world's first veterinary school in Lyon, France. Before this, medical doctors treated both humans and other animals. Modern scientific biomedical research (where results are testable and reproducible) began to replace early Western traditions based on herbalism, the Greek "four humours" and other such pre-modern notions. The modern era really began with Edward Jenner's discovery of the smallpox vaccine at the end of the 18th century (inspired by the method of variolation originated in ancient China), Robert Koch's discoveries around 1880 of the transmission of disease by bacteria, and then the discovery of antibiotics around 1900. The post-18th century modernity period brought more groundbreaking researchers from Europe. From Germany and Austria, doctors Rudolf Virchow, Wilhelm Conrad Röntgen, Karl Landsteiner and Otto Loewi made notable contributions. In the United Kingdom, Alexander Fleming, Joseph Lister, Francis Crick and Florence Nightingale are considered important. Spanish doctor Santiago Ramón y Cajal is considered the father of modern neuroscience. From New Zealand and Australia came Maurice Wilkins, Howard Florey, and Frank Macfarlane Burnet. Others that did significant work include William Williams Keen, William Coley, James D. Watson (United States); Salvador Luria (Italy); Alexandre Yersin (Switzerland); Kitasato Shibasaburō (Japan); Jean-Martin Charcot, Claude Bernard, Paul Broca (France); Adolfo Lutz (Brazil); Nikolai Korotkov (Russia); Sir William Osler (Canada); and Harvey Cushing (United States). As science and technology developed, medicine became more reliant upon medications. Throughout history and in Europe right until the late 18th century, not only plant products were used as medicine, but also animal (including human) body parts and fluids. Pharmacology developed in part from herbalism and some drugs are still derived from plants (atropine, ephedrine, warfarin, aspirin, digoxin, vinca alkaloids, taxol, hyoscine, etc.). Vaccines were discovered by Edward Jenner and Louis Pasteur. The first antibiotic was arsphenamine (Salvarsan) discovered by Paul Ehrlich in 1908 after he observed that bacteria took up toxic dyes that human cells did not. The first major class of antibiotics was the sulfa drugs, derived by German chemists originally from azo dyes. Pharmacology has become increasingly sophisticated; modern biotechnology allows drugs targeted towards specific physiological processes to be developed, sometimes designed for compatibility with the body to reduce side-effects. Genomics and knowledge of human genetics and human evolution is having increasingly significant influence on medicine, as the causative genes of most monogenic genetic disorders have now been identified, and the development of techniques in molecular biology, evolution, and genetics are influencing medical technology, practice and decision-making. Evidence-based medicine is a contemporary movement to establish the most effective algorithms of practice (ways of doing things) through the use of systematic reviews and meta-analysis. The movement is facilitated by modern global information science, which allows as much of the available evidence as possible to be collected and analyzed according to standard protocols that are then disseminated to healthcare providers. The Cochrane Collaboration leads this movement. A 2001 review of 160 Cochrane systematic reviews revealed that, according to two readers, 21.3% of the reviews concluded insufficient evidence, 20% concluded evidence of no effect, and 22.5% concluded positive effect. == Quality, efficiency, and access == Evidence-based medicine, prevention of medical error (and other "iatrogenesis"), and avoidance of unnecessary health care are a priority in modern medical systems. These topics generate significant political and public policy attention, particularly in the United States where healthcare is regarded as excessively costly but population health metrics lag similar nations. Globally, many developing countries lack access to care and access to medicines. As of 2015, most wealthy developed countries provide health care to all citizens, with a few exceptions such as the United States where lack of health insurance coverage may limit access. == See also == == Notes == == References ==
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Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils. The main branches of soil science are pedology ― the study of formation, chemistry, morphology, and classification of soil ― and edaphology ― the study of how soils interact with living things, especially plants. Sometimes terms which refer to those branches are used as if synonymous with soil science. The diversity of names associated with this discipline is related to the various associations concerned. Indeed, engineers, agronomists, chemists, geologists, physical geographers, ecologists, biologists, microbiologists, silviculturists, sanitarians, archaeologists, and specialists in regional planning, all contribute to further knowledge of soils and the advancement of the soil sciences. Soil scientists have raised concerns about how to preserve soil and arable land in a world with a growing population, possible future water crisis, increasing per capita food consumption, and land degradation. == Fields of study == Soil occupies the pedosphere, one of Earth's spheres that the geosciences use to organize the Earth conceptually. This is the conceptual perspective of pedology and edaphology, the two main branches of soil science. Pedology is the study of soil in its natural setting. Edaphology is the study of soil in relation to soil-dependent uses. Both branches apply a combination of soil physics, soil chemistry, and soil biology. Due to the numerous interactions between the biosphere, atmosphere and hydrosphere that are hosted within the pedosphere, more integrated, less soil-centric concepts are also valuable. Many concepts essential to understanding soil come from individuals not identifiable strictly as soil scientists. This highlights the interdisciplinary nature of soil concepts. == Research == Exploring the diversity and dynamics of soil continues to yield fresh discoveries and insights. New avenues of soil research are compelled by a need to understand soil in the context of climate change, greenhouse gases, and carbon sequestration. Interest in maintaining the planet's biodiversity and in exploring past cultures has also stimulated renewed interest in achieving a more refined understanding of soil. == Mapping == == Classification == In 1998, the World Reference Base for Soil Resources (WRB) replaced the FAO soil classification as the international soil classification system. The currently valid version of WRB is the 4th edition, 2022. The FAO soil classification, in turn, borrowed from modern soil classification concepts, including USDA soil taxonomy. WRB is based mainly on soil morphology as an expression of pedogenesis. A major difference with USDA soil taxonomy is that soil climate is not part of the system, except insofar as climate influences soil profile characteristics. Many other classification schemes exist, including vernacular systems. The structure in vernacular systems is either nominal (giving unique names to soils or landscapes) or descriptive (naming soils by their characteristics such as red, hot, fat, or sandy). Soils are distinguished by obvious characteristics, such as physical appearance (e.g., color, texture, landscape position), performance (e.g., production capability, flooding), and accompanying vegetation. A vernacular distinction familiar to many is classifying texture as heavy or light. Light soil content and better structure take less effort to turn and cultivate. Light soils do not necessarily weigh less than heavy soils on an air dry basis, nor do they have more porosity. == History == The earliest known soil classification system comes from China, appearing in the book Yu Gong (5th century BCE), where the soil was divided into three categories and nine classes, depending on its color, texture and hydrology. Contemporaries Friedrich Albert Fallou (the German founder of modern soil science) and Vasily Dokuchaev (the Russian founder of modern soil science) are both credited with being among the first to identify soil as a resource whose distinctness and complexity deserved to be separated conceptually from geology and crop production and treated as a whole. As a founding father of soil science, Fallou has primacy in time. Fallou was working on the origins of soil before Dokuchaev was born; however Dokuchaev's work was more extensive and is considered to be the more significant to modern soil theory than Fallou's. Previously, soil had been considered a product of chemical transformations of rocks, a dead substrate from which plants derive nutritious elements. Soil and bedrock were in fact equated. Dokuchaev considers the soil as a natural body having its own genesis and its own history of development, a body with complex and multiform processes taking place within it. The soil is considered as different from bedrock. The latter becomes soil under the influence of a series of soil-formation factors (climate, vegetation, country, relief and age). According to him, soil should be called the "daily" or outward horizons of rocks regardless of the type; they are changed naturally by the common effect of water, air and various kinds of living and dead organisms. A 1914 encyclopedic definition: "the different forms of earth on the surface of the rocks, formed by the breaking down or weathering of rocks". serves to illustrate the historic view of soil which persisted from the 19th century. Dokuchaev's late 19th century soil concept developed in the 20th century to one of soil as earthy material that has been altered by living processes. A corollary concept is that soil without a living component is simply a part of Earth's outer layer. Further refinement of the soil concept is occurring in view of an appreciation of energy transport and transformation within soil. The term is popularly applied to the material on the surface of the Earth's moon and Mars, a usage acceptable within a portion of the scientific community. Accurate to this modern understanding of soil is Nikiforoff's 1959 definition of soil as the "excited skin of the sub aerial part of the Earth's crust". == Areas of practice == Academically, soil scientists tend to be drawn to one of five areas of specialization: microbiology, pedology, edaphology, physics, or chemistry. Yet the work specifics are very much dictated by the challenges facing our civilization's desire to sustain the land that supports it, and the distinctions between the sub-disciplines of soil science often blur in the process. Soil science professionals commonly stay current in soil chemistry, soil physics, soil microbiology, pedology, and applied soil science in related disciplines. One exciting effort drawing in soil scientists in the U.S. as of 2004 is the Soil Quality Initiative. Central to the Soil Quality Initiative is developing indices of soil health and then monitoring them in a way that gives us long-term (decade-to-decade) feedback on our performance as stewards of the planet. The effort includes understanding the functions of soil microbiotic crusts and exploring the potential to sequester atmospheric carbon in soil organic matter. Relating the concept of agriculture to soil quality, however, has not been without its share of controversy and criticism, including critiques by Nobel Laureate Norman Borlaug and World Food Prize Winner Pedro Sanchez. A more traditional role for soil scientists has been to map soils. Almost every area in the United States now has a published soil survey, including interpretive tables on how soil properties support or limit activities and uses. An internationally accepted soil taxonomy allows uniform communication of soil characteristics and soil functions. National and international soil survey efforts have given the profession unique insights into landscape-scale functions. The landscape functions that soil scientists are called upon to address in the field seem to fall roughly into six areas: Land-based treatment of wastes Septic system Manure Municipal biosolids Food and fiber processing waste Identification and protection of environmentally critical areas Sensitive and unstable soils Wetlands Unique soil situations that support valuable habitat, and ecosystem diversity Management for optimum land productivity Silviculture Agronomy Nutrient management Water management Native vegetation Grazing Management for optimum water quality Stormwater management Sediment and erosion control Remediation and restoration of damaged lands Mine reclamation Flood and storm damage Contamination Sustainability of desired uses Soil conservation There are also practical applications of soil science that might not be apparent from looking at a published soil survey. Radiometric dating: specifically a knowledge of local pedology is used to date prior activity at the site Stratification (archeology) where soil formation processes and preservative qualities can inform the study of archaeological sites Geological phenomena Landslides Active faults Altering soils to achieve new uses Vitrification to contain radioactive wastes Enhancing soil microbial capabilities in degrading contaminants (bioremediation). Carbon sequestration Environmental soil science Pedology Soil genesis Pedometrics Soil morphology Soil micromorphology Soil classification USDA soil taxonomy World Reference Base for Soil Resources Soil biology Soil microbiology Soil chemistry Soil biochemistry Soil mineralogy Soil physics Pedotransfer function Soil mechanics and engineering Soil hydrology, hydropedology === Fields of application in soil science === Climate change Ecosystem studies Pedotransfer function Soil fertility / Nutrient management Soil management Soil survey Standard methods of analysis Watershed and wetland studies Land Suitability classification === Related disciplines === Agricultural sciences Agricultural soil science Agrophysics science Irrigation management Anthropology archaeological stratigraphy Environmental science Landscape ecology Physical geography Geomorphology Geology Biogeochemistry Geomicrobiology Hydrology Hydrogeology Waste management Wetland science == Depression storage capacity == Depression storage capacity, in soil science, is the ability of a particular area of land to retain water in its pits and depressions, thus preventing it from flowing. Depression storage capacity, along with infiltration capacity, is one of the main factors involved in Horton overland flow, whereby water volume surpasses both infiltration and depression storage capacity and begins to flow horizontally across land, possibly leading to flooding and soil erosion. The study of land's depression storage capacity is important in the fields of geology, ecology, and especially hydrology. == See also == == References == Soil Survey Staff (1993). Soil Survey: Early Concepts of Soil. (html) Soil Survey Manual USDA Handbook 18, Soil Conservation Service. U.S. Department of Agriculture. URL accessed on 2004-11-30. Marion LeRoy Jackson (2005). Soil Chemical Analysis: Advanced Course. UW-Madison Libraries Parallel Press. pp. 5–. ISBN 978-1-893311-47-3. == External links == Media related to Soil science at Wikimedia Commons
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https://en.wikipedia.org/wiki/Soil_science
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Forensic science, often confused with criminalistics, is the application of science principles and methods to support legal decision-making in matters of criminal and civil law. During criminal investigation in particular, it is governed by the legal standards of admissible evidence and criminal procedure. It is a broad field utilizing numerous practices such as the analysis of DNA, fingerprints, bloodstain patterns, firearms, ballistics, toxicology, microscopy, and fire debris analysis. Forensic scientists collect, preserve, and analyze evidence during the course of an investigation. While some forensic scientists travel to the scene of the crime to collect the evidence themselves, others occupy a laboratory role, performing analysis on objects brought to them by other individuals. Others are involved in analysis of financial, banking, or other numerical data for use in financial crime investigation, and can be employed as consultants from private firms, academia, or as government employees. In addition to their laboratory role, forensic scientists testify as expert witnesses in both criminal and civil cases and can work for either the prosecution or the defense. While any field could technically be forensic, certain sections have developed over time to encompass the majority of forensically related cases. == Etymology == The term forensic stems from the Latin word, forēnsis (3rd declension, adjective), meaning "of a forum, place of assembly". The history of the term originates in Roman times, when a criminal charge meant presenting the case before a group of public individuals in the forum. Both the person accused of the crime and the accuser would give speeches based on their sides of the story. The case would be decided in favor of the individual with the best argument and delivery. This origin is the source of the two modern usages of the word forensic—as a form of legal evidence; and as a category of public presentation. In modern use, the term forensics is often used in place of "forensic science." The word "science", is derived from the Latin word for 'knowledge' and is today closely tied to the scientific method, a systematic way of acquiring knowledge. Taken together, forensic science means the use of scientific methods and processes for crime solving. == History == === Origins of forensic science and early methods === The ancient world lacked standardized forensic practices, which enabled criminals to escape punishment. Criminal investigations and trials relied heavily on forced confessions and witness testimony. However, ancient sources do contain several accounts of techniques that foreshadow concepts in forensic science developed centuries later. The first written account of using medicine and entomology to solve criminal cases is attributed to the book of Xi Yuan Lu (translated as Washing Away of Wrongs), written in China in 1248 by Song Ci (宋慈, 1186–1249), a director of justice, jail and supervision, during the Song dynasty. Song Ci introduced regulations concerning autopsy reports to court, how to protect the evidence in the examining process, and explained why forensic workers must demonstrate impartiality to the public. He devised methods for making antiseptic and for promoting the reappearance of hidden injuries to dead bodies and bones (using sunlight and vinegar under a red-oil umbrella); for calculating the time of death (allowing for weather and insect activity); described how to wash and examine the dead body to ascertain the reason for death. At that time the book had described methods for distinguishing between suicide and faked suicide. He wrote the book on forensics stating that all wounds or dead bodies should be examined, not avoided. The book became the first form of literature to help determine the cause of death. In one of Song Ci's accounts (Washing Away of Wrongs), the case of a person murdered with a sickle was solved by an investigator who instructed each suspect to bring his sickle to one location. (He realized it was a sickle by testing various blades on an animal carcass and comparing the wounds.) Flies, attracted by the smell of blood, eventually gathered on a single sickle. In light of this, the owner of that sickle confessed to the murder. The book also described how to distinguish between a drowning (water in the lungs) and strangulation (broken neck cartilage), and described evidence from examining corpses to determine if a death was caused by murder, suicide or accident. Methods from around the world involved saliva and examination of the mouth and tongue to determine innocence or guilt, as a precursor to the Polygraph test. In ancient India, some suspects were made to fill their mouths with dried rice and spit it back out. Similarly, in ancient China, those accused of a crime would have rice powder placed in their mouths. In ancient middle-eastern cultures, the accused were made to lick hot metal rods briefly. It is thought that these tests had some validity since a guilty person would produce less saliva and thus have a drier mouth; the accused would be considered guilty if rice was sticking to their mouths in abundance or if their tongues were severely burned due to lack of shielding from saliva. == Education and training == Initial glance, forensic intelligence may appear as a nascent facet of forensic science facilitated by advancements in information technologies such as computers, databases, and data-flow management software. However, a more profound examination reveals that forensic intelligence represents a genuine and emerging inclination among forensic practitioners to actively participate in investigative and policing strategies. In doing so, it elucidates existing practices within scientific literature, advocating for a paradigm shift from the prevailing conception of forensic science as a conglomerate of disciplines merely aiding the criminal justice system. Instead, it urges a perspective that views forensic science as a discipline studying the informative potential of traces—remnants of criminal activity. Embracing this transformative shift poses a significant challenge for education, necessitating a shift in learners' mindset to accept concepts and methodologies in forensic intelligence. Recent calls advocating for the integration of forensic scientists into the criminal justice system, as well as policing and intelligence missions, underscore the necessity for the establishment of educational and training initiatives in the field of forensic intelligence. This article contends that a discernible gap exists between the perceived and actual comprehension of forensic intelligence among law enforcement and forensic science managers, positing that this asymmetry can be rectified only through educational interventions. The primary challenge in forensic intelligence education and training is identified as the formulation of programs aimed at heightening awareness, particularly among managers, to mitigate the risk of making suboptimal decisions in information processing. The paper highlights two recent European courses as exemplars of educational endeavors, elucidating lessons learned and proposing future directions. The overarching conclusion is that the heightened focus on forensic intelligence has the potential to rejuvenate a proactive approach to forensic science, enhance quantifiable efficiency, and foster greater involvement in investigative and managerial decision-making. A novel educational challenge is articulated for forensic science university programs worldwide: a shift in emphasis from a fragmented criminal trace analysis to a more comprehensive security problem-solving approach. === Development of forensic science === In 16th-century Europe, medical practitioners in army and university settings began to gather information on the cause and manner of death. Ambroise Paré, a French army surgeon, systematically studied the effects of violent death on internal organs. Two Italian surgeons, Fortunato Fidelis and Paolo Zacchia, laid the foundation of modern pathology by studying changes that occurred in the structure of the body as the result of disease. In the late 18th century, writings on these topics began to appear. These included A Treatise on Forensic Medicine and Public Health by the French physician François-Emmanuel Fodéré and The Complete System of Police Medicine by the German medical expert Johann Peter Frank. As the rational values of the Enlightenment era increasingly permeated society in the 18th century, criminal investigation became a more evidence-based, rational procedure − the use of torture to force confessions was curtailed, and belief in witchcraft and other powers of the occult largely ceased to influence the court's decisions. Two examples of English forensic science in individual legal proceedings demonstrate the increasing use of logic and procedure in criminal investigations at the time. In 1784, in Lancaster, John Toms was tried and convicted for murdering Edward Culshaw with a pistol. When the dead body of Culshaw was examined, a pistol wad (crushed paper used to secure powder and balls in the muzzle) found in his head wound matched perfectly with a torn newspaper found in Toms's pocket, leading to the conviction. In Warwick 1816, a farm laborer was tried and convicted of the murder of a young maidservant. She had been drowned in a shallow pool and bore the marks of violent assault. The police found footprints and an impression from corduroy cloth with a sewn patch in the damp earth near the pool. There were also scattered grains of wheat and chaff. The breeches of a farm labourer who had been threshing wheat nearby were examined and corresponded exactly to the impression in the earth near the pool. An article appearing in Scientific American in 1885 describes the use of microscopy to distinguish between the blood of two persons in a criminal case in Chicago. === Chromatography === Chromatography is a common technique used in the field of Forensic Science. Chromatography is a method of separating the components of a mixture from a mobile phase. Chromatography is an essential tool used in forensic science, helping analysts identify and compare trace amounts of samples including ignitable liquids, drugs, and biological samples. Many laboratories utilize gas chromatography/mass spectrometry (GC/MS) to examine these kinds of samples; this analysis provides rapid and reliant data to identify samples in question. === Toxicology === A method for detecting arsenious oxide, simple arsenic, in corpses was devised in 1773 by the Swedish chemist, Carl Wilhelm Scheele. His work was expanded upon, in 1806, by German chemist Valentin Ross, who learned to detect the poison in the walls of a victim's stomach. Toxicology, a subfield of forensic chemistry, focuses on detecting and identifying drugs, poisons, and other toxic substances in biological samples. Forensic toxicologists work on cases involving drug overdoses, poisoning, and substance abuse. Their work is critical in determining whether harmful substances play a role in a person’s death or impairment. read more James Marsh was the first to apply this new science to the art of forensics. He was called by the prosecution in a murder trial to give evidence as a chemist in 1832. The defendant, John Bodle, was accused of poisoning his grandfather with arsenic-laced coffee. Marsh performed the standard test by mixing a suspected sample with hydrogen sulfide and hydrochloric acid. While he was able to detect arsenic as yellow arsenic trisulfide, when it was shown to the jury it had deteriorated, allowing the suspect to be acquitted due to reasonable doubt. Annoyed by that, Marsh developed a much better test. He combined a sample containing arsenic with sulfuric acid and arsenic-free zinc, resulting in arsine gas. The gas was ignited, and it decomposed to pure metallic arsenic, which, when passed to a cold surface, would appear as a silvery-black deposit. So sensitive was the test, known formally as the Marsh test, that it could detect as little as one-fiftieth of a milligram of arsenic. He first described this test in The Edinburgh Philosophical Journal in 1836. === Ballistics and firearms === Ballistics is "the science of the motion of projectiles in flight". In forensic science, analysts examine the patterns left on bullets and cartridge casings after being ejected from a weapon. When fired, a bullet is left with indentations and markings that are unique to the barrel and firing pin of the firearm that ejected the bullet. This examination can help scientists identify possible makes and models of weapons connected to a crime. Henry Goddard at Scotland Yard pioneered the use of bullet comparison in 1835. He noticed a flaw in the bullet that killed the victim and was able to trace this back to the mold that was used in the manufacturing process. === Anthropometry === The French police officer Alphonse Bertillon was the first to apply the anthropological technique of anthropometry to law enforcement, thereby creating an identification system based on physical measurements. Before that time, criminals could be identified only by name or photograph. Dissatisfied with the ad hoc methods used to identify captured criminals in France in the 1870s, he began his work on developing a reliable system of anthropometrics for human classification. Bertillon created many other forensics techniques, including forensic document examination, the use of galvanoplastic compounds to preserve footprints, ballistics, and the dynamometer, used to determine the degree of force used in breaking and entering. Although his central methods were soon to be supplanted by fingerprinting, "his other contributions like the mug shot and the systematization of crime-scene photography remain in place to this day." === Fingerprints === Sir William Herschel was one of the first to advocate the use of fingerprinting in the identification of criminal suspects. While working for the Indian Civil Service, he began to use thumbprints on documents as a security measure to prevent the then-rampant repudiation of signatures in 1858. In 1877 at Hooghly (near Kolkata), Herschel instituted the use of fingerprints on contracts and deeds, and he registered government pensioners' fingerprints to prevent the collection of money by relatives after a pensioner's death. In 1880, Henry Faulds, a Scottish surgeon in a Tokyo hospital, published his first paper on the subject in the scientific journal Nature, discussing the usefulness of fingerprints for identification and proposing a method to record them with printing ink. He established their first classification and was also the first to identify fingerprints left on a vial. Returning to the UK in 1886, he offered the concept to the Metropolitan Police in London, but it was dismissed at that time. Faulds wrote to Charles Darwin with a description of his method, but, too old and ill to work on it, Darwin gave the information to his cousin, Francis Galton, who was interested in anthropology. Having been thus inspired to study fingerprints for ten years, Galton published a detailed statistical model of fingerprint analysis and identification and encouraged its use in forensic science in his book Finger Prints. He had calculated that the chance of a "false positive" (two different individuals having the same fingerprints) was about 1 in 64 billion. Juan Vucetich, an Argentine chief police officer, created the first method of recording the fingerprints of individuals on file. In 1892, after studying Galton's pattern types, Vucetich set up the world's first fingerprint bureau. In that same year, Francisca Rojas of Necochea was found in a house with neck injuries whilst her two sons were found dead with their throats cut. Rojas accused a neighbour, but despite brutal interrogation, this neighbour would not confess to the crimes. Inspector Alvarez, a colleague of Vucetich, went to the scene and found a bloody thumb mark on a door. When it was compared with Rojas' prints, it was found to be identical with her right thumb. She then confessed to the murder of her sons. A Fingerprint Bureau was established in Calcutta (Kolkata), India, in 1897, after the Council of the Governor General approved a committee report that fingerprints should be used for the classification of criminal records. Working in the Calcutta Anthropometric Bureau, before it became the Fingerprint Bureau, were Azizul Haque and Hem Chandra Bose. Haque and Bose were Indian fingerprint experts who have been credited with the primary development of a fingerprint classification system eventually named after their supervisor, Sir Edward Richard Henry. The Henry Classification System, co-devised by Haque and Bose, was accepted in England and Wales when the first United Kingdom Fingerprint Bureau was founded in Scotland Yard, the Metropolitan Police headquarters, London, in 1901. Sir Edward Richard Henry subsequently achieved improvements in dactyloscopy. In the United States, Henry P. DeForrest used fingerprinting in the New York Civil Service in 1902, and by December 1905, New York City Police Department Deputy Commissioner Joseph A. Faurot, an expert in the Bertillon system and a fingerprint advocate at Police Headquarters, introduced the fingerprinting of criminals to the United States. === Uhlenhuth test === The Uhlenhuth test, or the antigen–antibody precipitin test for species, was invented by Paul Uhlenhuth in 1901 and could distinguish human blood from animal blood, based on the discovery that the blood of different species had one or more characteristic proteins. The test represented a major breakthrough and came to have tremendous importance in forensic science. The test was further refined for forensic use by the Swiss chemist Maurice Müller in the year 1960s. === DNA === Forensic DNA analysis was first used in 1984. It was developed by Sir Alec Jeffreys, who realized that variation in the genetic sequence could be used to identify individuals and to tell individuals apart from one another. The first application of DNA profiles was used by Jeffreys in a double murder mystery in the small English town of Narborough, Leicestershire, in 1985. A 15-year-old school girl by the name of Lynda Mann was raped and murdered in Carlton Hayes psychiatric hospital. The police did not find a suspect but were able to obtain a semen sample. In 1986, Dawn Ashworth, 15 years old, was also raped and strangled in the nearby village of Enderby. Forensic evidence showed that both killers had the same blood type. Richard Buckland became the suspect because he worked at Carlton Hayes psychiatric hospital, had been spotted near Dawn Ashworth's murder scene and knew unreleased details about the body. He later confessed to Dawn's murder but not Lynda's. Jefferys was brought into the case to analyze the semen samples. He concluded that there was no match between the samples and Buckland, who became the first person to be exonerated using DNA. Jefferys confirmed that the DNA profiles were identical for the two murder semen samples. To find the perpetrator, DNA samples from the entire male population, more than 4,000 aged from 17 to 34, of the town were collected. They all were compared to semen samples from the crime. A friend of Colin Pitchfork was heard saying that he had given his sample to the police claiming to be Colin. Colin Pitchfork was arrested in 1987 and it was found that his DNA profile matched the semen samples from the murder. Because of this case, DNA databases were developed. There is the national (FBI) and international databases as well as the European countries (ENFSI: European Network of Forensic Science Institutes). These searchable databases are used to match crime scene DNA profiles to those already in a database. === Maturation === By the turn of the 20th century, the science of forensics had become largely established in the sphere of criminal investigation. Scientific and surgical investigation was widely employed by the Metropolitan Police during their pursuit of the mysterious Jack the Ripper, who had killed a number of women in the 1880s. This case is a watershed in the application of forensic science. Large teams of policemen conducted house-to-house inquiries throughout Whitechapel. Forensic material was collected and examined. Suspects were identified, traced and either examined more closely or eliminated from the inquiry. Police work follows the same pattern today. Over 2000 people were interviewed, "upwards of 300" people were investigated, and 80 people were detained. The investigation was initially conducted by the Criminal Investigation Department (CID), headed by Detective Inspector Edmund Reid. Later, Detective Inspectors Frederick Abberline, Henry Moore, and Walter Andrews were sent from Central Office at Scotland Yard to assist. Initially, butchers, surgeons and physicians were suspected because of the manner of the mutilations. The alibis of local butchers and slaughterers were investigated, with the result that they were eliminated from the inquiry. Some contemporary figures thought the pattern of the murders indicated that the culprit was a butcher or cattle drover on one of the cattle boats that plied between London and mainland Europe. Whitechapel was close to the London Docks, and usually such boats docked on Thursday or Friday and departed on Saturday or Sunday. The cattle boats were examined, but the dates of the murders did not coincide with a single boat's movements, and the transfer of a crewman between boats was also ruled out. At the end of October, Robert Anderson asked police surgeon Thomas Bond to give his opinion on the extent of the murderer's surgical skill and knowledge. The opinion offered by Bond on the character of the "Whitechapel murderer" is the earliest surviving offender profile. Bond's assessment was based on his own examination of the most extensively mutilated victim and the post mortem notes from the four previous canonical murders. In his opinion the killer must have been a man of solitary habits, subject to "periodical attacks of homicidal and erotic mania", with the character of the mutilations possibly indicating "satyriasis". Bond also stated that "the homicidal impulse may have developed from a revengeful or brooding condition of the mind, or that religious mania may have been the original disease but I do not think either hypothesis is likely". Handbook for Coroners, police officials, military policemen was written by the Austrian criminal jurist Hans Gross in 1893, and is generally acknowledged as the birth of the field of criminalistics. The work combined in one system fields of knowledge that had not been previously integrated, such as psychology and physical science, and which could be successfully used against crime. Gross adapted some fields to the needs of criminal investigation, such as crime scene photography. He went on to found the Institute of Criminalistics in 1912, as part of the University of Graz' Law School. This Institute was followed by many similar institutes all over the world. In 1909, Archibald Reiss founded the Institut de police scientifique of the University of Lausanne (UNIL), the first school of forensic science in the world. Dr. Edmond Locard, became known as the "Sherlock Holmes of France". He formulated the basic principle of forensic science: "Every contact leaves a trace", which became known as Locard's exchange principle. In 1910, he founded what may have been the first criminal laboratory in the world, after persuading the Police Department of Lyon (France) to give him two attic rooms and two assistants. Symbolic of the newfound prestige of forensics and the use of reasoning in detective work was the popularity of the fictional character Sherlock Holmes, written by Arthur Conan Doyle in the late 19th century. He remains a great inspiration for forensic science, especially for the way his acute study of a crime scene yielded small clues as to the precise sequence of events. He made great use of trace evidence such as shoe and tire impressions, as well as fingerprints, ballistics and handwriting analysis, now known as questioned document examination. Such evidence is used to test theories conceived by the police, for example, or by the investigator himself. All of the techniques advocated by Holmes later became reality, but were generally in their infancy at the time Conan Doyle was writing. In many of his reported cases, Holmes frequently complains of the way the crime scene has been contaminated by others, especially by the police, emphasising the critical importance of maintaining its integrity, a now well-known feature of crime scene examination. He used analytical chemistry for blood residue analysis as well as toxicology examination and determination for poisons. He used ballistics by measuring bullet calibres and matching them with a suspected murder weapon. === Late 19th – early 20th century figures === Hans Gross applied scientific methods to crime scenes and was responsible for the birth of criminalistics. Edmond Locard expanded on Gross' work with Locard's exchange principle which stated "whenever two objects come into contact with one another, materials are exchanged between them". This means that every contact by a criminal leaves a trace. Alexandre Lacassagne, who taught Locard, produced autopsy standards on actual forensic cases. Alphonse Bertillon was a French criminologist and founder of Anthropometry (scientific study of measurements and proportions of the human body). He used anthropometry for identification, stating that, since each individual is unique, by measuring aspects of physical difference there could be a personal identification system. He created the Bertillon System around 1879, a way of identifying criminals and citizens by measuring 20 parts of the body. In 1884, over 240 repeat offenders were caught using the Bertillon system, but the system was largely superseded by fingerprinting. Joseph Thomas Walker, known for his work at Massachusetts State Police Chemical Laboratory, for developing many modern forensic techniques which he frequently published in academic journals, and for teaching at the Department of Legal Medicine, Harvard University. Frances Glessner Lee, known as "the mother of forensic science", was instrumental in the development of forensic science in the US. She lobbied to have coroners replaced by medical professionals, endowed the Harvard Associates in Police Science, and conducted many seminars to educate homicide investigators. She also created the Nutshell Studies of Unexplained Death, intricate crime scene dioramas used to train investigators, which are still in use today. === 20th century === Later in the 20th century several British pathologists, Mikey Rochman, Francis Camps, Sydney Smith and Keith Simpson pioneered new forensic science methods. Alec Jeffreys pioneered the use of DNA profiling in forensic science in 1984. He realized the scope of DNA fingerprinting, which uses variations in the genetic code to identify individuals. The method has since become important in forensic science to assist police detective work, and it has also proved useful in resolving paternity and immigration disputes. DNA fingerprinting was first used as a police forensic test to identify the rapist and killer of two teenagers, Lynda Mann and Dawn Ashworth, who were both murdered in Narborough, Leicestershire, in 1983 and 1986 respectively. Colin Pitchfork was identified and convicted of murder after samples taken from him matched semen samples taken from the two dead girls. Forensic science has been fostered by a number of national and international forensic science learned bodies including the American Academy of Forensic Sciences (founded 1948), publishers of the Journal of Forensic Sciences; the Canadian Society of Forensic Science (founded 1953), publishers of the Journal of the Canadian Society of Forensic Science; the Chartered Society of Forensic Sciences, (founded 1959), then known as the Forensic Science Society, publisher of Science & Justice; the British Academy of Forensic Sciences (founded 1960), publishers of Medicine, Science and the Law; the Australian Academy of Forensic Sciences (founded 1967), publishers of the Australian Journal of Forensic Sciences; and the European Network of Forensic Science Institutes (founded 1995). === 21st century === In the past decade, documenting forensics scenes has become more efficient. Forensic scientists have started using laser scanners, drones and photogrammetry to obtain 3D point clouds of accidents or crime scenes. Reconstruction of an accident scene on a highway using drones involves data acquisition time of only 10–20 minutes and can be performed without shutting down traffic. The results are not just accurate, in centimeters, for measurement to be presented in court but also easy to digitally preserve in the long term. Now, in the 21st century, much of forensic science's future is up for discussion. The National Institute of Standards and Technology (NIST) has several forensic science-related programs: CSAFE, a NIST Center of Excellence in Forensic Science, the National Commission on Forensic Science (now concluded), and administration of the Organization of Scientific Area Committees for Forensic Science (OSAC). One of the more recent additions by NIST is a document called NISTIR-7941, titled "Forensic Science Laboratories: Handbook for Facility Planning, Design, Construction, and Relocation". The handbook provides a clear blueprint for approaching forensic science. The details even include what type of staff should be hired for certain positions. == Subdivisions == Art forensics concerns the art authentication cases to help research the work's authenticity. Art authentication methods are used to detect and identify forgery, faking and copying of art works, e.g. paintings. Bloodstain pattern analysis is the scientific examination of blood spatter patterns found at a crime scene to reconstruct the events of the crime. Comparative forensics is the application of visual comparison techniques to verify similarity of physical evidence. This includes fingerprint analysis, toolmark analysis, and ballistic analysis. Computational forensics concerns the development of algorithms and software to assist forensic examination. Criminalistics is the application of various sciences to answer questions relating to examination and comparison of biological evidence, trace evidence, impression evidence (such as fingerprints, footwear impressions, and tire tracks), controlled substances, ballistics, firearm and toolmark examination, and other evidence in criminal investigations. In typical circumstances, evidence is processed in a crime lab. Digital forensics is the application of proven scientific methods and techniques in order to recover data from electronic / digital media. Digital Forensic specialists work in the field as well as in the lab. Ear print analysis is used as a means of forensic identification intended as an identification tool similar to fingerprinting. An earprint is a two-dimensional reproduction of the parts of the outer ear that have touched a specific surface (most commonly the helix, antihelix, tragus and antitragus). Election forensics is the use of statistics to determine if election results are normal or abnormal. It is also used to look into and detect the cases concerning gerrymandering. Forensic accounting is the study and interpretation of accounting evidence, financial statement namely: Balance sheet, Income statement, Cash flow statement. Forensic aerial photography is the study and interpretation of aerial photographic evidence. Forensic anthropology is the application of physical anthropology in a legal setting, usually for the recovery and identification of skeletonized human remains. Forensic archaeology is the application of a combination of archaeological techniques and forensic science, typically in law enforcement. Forensic astronomy uses methods from astronomy to determine past celestial constellations for forensic purposes. Forensic botany is the study of plant life in order to gain information regarding possible crimes. Forensic chemistry is the study of detection and identification of illicit drugs, accelerants used in arson cases, explosive and gunshot residue. Forensic dactyloscopy is the study of fingerprints. Forensic document examination or questioned document examination answers questions about a disputed document using a variety of scientific processes and methods. Many examinations involve a comparison of the questioned document, or components of the document, with a set of known standards. The most common type of examination involves handwriting, whereby the examiner tries to address concerns about potential authorship. Forensic DNA analysis takes advantage of the uniqueness of an individual's DNA to answer forensic questions such as paternity/maternity testing and placing a suspect at a crime scene, e.g. in a rape investigation. Forensic engineering is the scientific examination and analysis of structures and products relating to their failure or cause of damage. Forensic entomology deals with the examination of insects in, on and around human remains to assist in determination of time or location of death. It is also possible to determine if the body was moved after death using entomology. Forensic geology deals with trace evidence in the form of soils, minerals and petroleum. Forensic geomorphology is the study of the ground surface to look for potential location(s) of buried object(s). Forensic geophysics is the application of geophysical techniques such as radar for detecting objects hidden underground or underwater. Forensic intelligence process starts with the collection of data and ends with the integration of results within into the analysis of crimes under investigation. Forensic interviews are conducted using the science of professionally using expertise to conduct a variety of investigative interviews with victims, witnesses, suspects or other sources to determine the facts regarding suspicions, allegations or specific incidents in either public or private sector settings. Forensic histopathology is the application of histological techniques and examination to forensic pathology practice. Forensic limnology is the analysis of evidence collected from crime scenes in or around fresh-water sources. Examination of biological organisms, in particular diatoms, can be useful in connecting suspects with victims. Forensic linguistics deals with issues in the legal system that requires linguistic expertise. Forensic meteorology is a site-specific analysis of past weather conditions for a point of loss. Forensic metrology is the application of metrology to assess the reliability of scientific evidence obtained through measurements Forensic microbiology is the study of the necrobiome. Forensic nursing is the application of Nursing sciences to abusive crimes, like child abuse, or sexual abuse. Categorization of wounds and traumas, collection of bodily fluids and emotional support are some of the duties of forensic nurses. Forensic odontology is the study of the uniqueness of dentition, better known as the study of teeth. Forensic optometry is the study of glasses and other eyewear relating to crime scenes and criminal investigations. Forensic pathology is a field in which the principles of medicine and pathology are applied to determine a cause of death or injury in the context of a legal inquiry. Forensic podiatry is an application of the study of feet footprint or footwear and their traces to analyze scene of crime and to establish personal identity in forensic examinations. Forensic psychiatry is a specialized branch of psychiatry as applied to and based on scientific criminology. Forensic psychology is the study of the mind of an individual, using forensic methods. Usually it determines the circumstances behind a criminal's behavior. Forensic seismology is the study of techniques to distinguish the seismic signals generated by underground nuclear explosions from those generated by earthquakes. Forensic serology is the study of the body fluids. Forensic social work is the specialist study of social work theories and their applications to a clinical, criminal justice or psychiatric setting. Practitioners of forensic social work connected with the criminal justice system are often termed Social Supervisors, whilst the remaining use the interchangeable titles forensic social worker, approved mental health professional or forensic practitioner and they conduct specialist assessments of risk, care planning and act as an officer of the court. Forensic toxicology is the study of the effect of drugs and poisons on/in the human body. Forensic video analysis is the scientific examination, comparison and evaluation of video in legal matters. Mobile device forensics is the scientific examination and evaluation of evidence found in mobile phones, e.g. Call History and Deleted SMS, and includes SIM Card Forensics. Trace evidence analysis is the analysis and comparison of trace evidence including glass, paint, fibres and hair (e.g., using micro-spectrophotometry). Wildlife forensic science applies a range of scientific disciplines to legal cases involving non-human biological evidence, to solve crimes such as poaching, animal abuse, and trade in endangered species. == Questionable techniques == Some forensic techniques, believed to be scientifically sound at the time they were used, have turned out later to have much less scientific merit or none. Some such techniques include: Comparative bullet-lead analysis was used by the FBI for over four decades, starting with the John F. Kennedy assassination in 1963. The theory was that each batch of ammunition possessed a chemical makeup so distinct that a bullet could be traced back to a particular batch or even a specific box. Internal studies and an outside study by the National Academy of Sciences found that the technique was unreliable due to improper interpretation, and the FBI abandoned the test in 2005. Forensic dentistry has come under fire: in at least three cases bite-mark evidence has been used to convict people of murder who were later freed by DNA evidence. A 1999 study by a member of the American Board of Forensic Odontology found a 63 percent rate of false identifications and is commonly referenced within online news stories and conspiracy websites. The study was based on an informal workshop during an ABFO meeting, which many members did not consider a valid scientific setting. The theory is that each person has a unique and distinctive set of teeth, which leave a pattern after biting someone. They analyze the dental characteristics such as size, shape, and arch form. Police Access to Genetic Genealogy Databases: There are privacy concerns with the police being able to access personal genetic data that is on genealogy services. Individuals can become criminal informants to their own families or to themselves simply by participating in genetic genealogy databases. The Combined DNA Index System (CODIS) is a database that the FBI uses to hold genetic profiles of all known felons, misdemeanants, and arrestees. Some people argue that individuals who are using genealogy databases should have an expectation of privacy in their data that is or may be violated by genetic searches by law enforcement. These different services have warning signs about potential third parties using their information, but most individuals do not read the agreement thoroughly. According to a study by Christi Guerrini, Jill Robinson, Devan Petersen, and Amy McGuire, they found that the majority of the people who took the survey support police searches of genetic websites that identify genetic relatives. People who responded to the survey are more supportive of police activities using genetic genealogy when it is for the purpose of identifying offenders of violent crimes, suspects of crimes against children or missing people. The data from the surveys that were given show that individuals are not concerned about police searches using personal genetic data if it is justified. It was found in this study that offenders are disproportionally low-income and black and the average person of genetic testing is wealthy and white. The results from the study had different results. In 2016, there was a survey called the National Crime Victimization Survey (NCVS) that was provided by the US Bureau of Justice Statistics. In that survey, it was found that 1.3% of people aged 12 or older were victims of violent crimes, and 8.85 of households were victims of property crimes. There were some issues with this survey though. The NCVS produces only the annual estimates of victimization. The survey that Christi Guerrini, Jill Robinson, Devan Petersen, and Amy McGuire produced asked the participants about the incidents of victimization over one's lifetime. Their survey also did not restrict other family members to one household. Around 25% of people who responded to the survey said that they have had family members that have been employed by law enforcement which includes security guards and bailiffs. Throughout these surveys, it has been found that there is public support for law enforcement to access genetic genealogy databases. == Litigation science == "Litigation science" describes analysis or data developed or produced expressly for use in a trial versus those produced in the course of independent research. This distinction was made by the U.S. 9th Circuit Court of Appeals when evaluating the admissibility of experts. This uses demonstrative evidence, which is evidence created in preparation of trial by attorneys or paralegals. == Demographics == As of 2025, there are currently an estimated 18,500 forensic science technicians in the United States. == Media impact == Real-life crime scene investigators and forensic scientists warn that popular television shows do not give a realistic picture of the work, often wildly distorting its nature, and exaggerating the ease, speed, effectiveness, drama, glamour, influence and comfort level of their jobs—which they describe as far more mundane, tedious and boring. Some claim these modern TV shows have changed individuals' expectations of forensic science, sometimes unrealistically—an influence termed the "CSI effect". Further, research has suggested that public misperceptions about criminal forensics can create, in the mind of a juror, unrealistic expectations of forensic evidence—which they expect to see before convicting—implicitly biasing the juror towards the defendant. Citing the "CSI effect," at least one researcher has suggested screening jurors for their level of influence from such TV programs. Further, research has shown that newspaper media has been found to shape readers general knowledge and perceptions of science and technology in a rather positive way. It could lead to support of it due to the interest readers may obtain and seek further knowledge on the topic. == Controversies == Questions about certain areas of forensic science, such as fingerprint evidence and the assumptions behind these disciplines have been brought to light in some publications including the New York Post. The article stated that "No one has proved even the basic assumption: That everyone's fingerprint is unique." The article also stated that "Now such assumptions are being questioned—and with it may come a radical change in how forensic science is used by police departments and prosecutors." Law professor Jessica Gabel said on NOVA that forensic science "lacks the rigors, the standards, the quality controls and procedures that we find, usually, in science". The National Institute of Standards and Technology has reviewed the scientific foundations of bite-mark analysis used in forensic science. Bite mark analysis is a forensic science technique that analyzes the marks on the victim's skin compared to the suspects teeth. NIST reviewed the findings of the National Academies of Sciences, Engineering, and Medicine 2009 study. The National Academics of Sciences, Engineering, and Medicine conducted research to address the issues of reliability, accuracy, and reliability of bitemark analysis, where they concluded that there is a lack of sufficient scientific foundation to support the data. Yet the technique is still legal to use in court as evidence. NIST funded a 2019 meeting that consisted of dentists, lawyers, researchers and others to address the gaps in this field. In the US, on 25 June 2009, the Supreme Court issued a 5-to-4 decision in Melendez-Diaz v. Massachusetts stating that crime laboratory reports may not be used against criminal defendants at trial unless the analysts responsible for creating them give testimony and subject themselves to cross-examination. The Supreme Court cited the National Academies of Sciences report Strengthening Forensic Science in the United States in their decision. Writing for the majority, Justice Antonin Scalia referred to the National Research Council report in his assertion that "Forensic evidence is not uniquely immune from the risk of manipulation." In the US, another area of forensic science that has come under question in recent years is the lack of laws requiring the accreditation of forensic labs. Some states require accreditation, but some states do not. Because of this, many labs have been caught performing very poor work resulting in false convictions or acquittals. For example, it was discovered after an audit of the Houston Police Department in 2002 that the lab had fabricated evidence which led George Rodriguez being convicted of raping a fourteen-year-old girl. The former director of the lab, when asked, said that the total number of cases that could have been contaminated by improper work could be in the range of 5,000 to 10,000. The Innocence Project database of DNA exonerations shows that many wrongful convictions contained forensic science errors. According to the Innocence project and the US Department of Justice, forensic science has contributed to about 39 percent to 46 percent of wrongful convictions. As indicated by the National Academy of Sciences report Strengthening Forensic Sciences in the United States, part of the problem is that many traditional forensic sciences have never been empirically validated; and part of the problem is that all examiners are subject to forensic confirmation biases and should be shielded from contextual information not relevant to the judgment they make. Many studies have discovered a difference in rape-related injuries reporting based on race, with white victims reporting a higher frequency of injuries than black victims. However, since current forensic examination techniques may not be sensitive to all injuries across a range of skin colors, more research needs to be conducted to understand if this trend is due to skin confounding healthcare providers when examining injuries or if darker skin extends a protective element. In clinical practice, for patients with darker skin, one study recommends that attention must be paid to the thighs, labia majora, posterior fourchette and fossa navicularis, so that no rape-related injuries are missed upon close examination. == Forensic science and humanitarian work == The International Committee of the Red Cross (ICRC) uses forensic science for humanitarian purposes to clarify the fate of missing persons after armed conflict, disasters or migration, and is one of the services related to Restoring Family Links and Missing Persons. Knowing what has happened to a missing relative can often make it easier to proceed with the grieving process and move on with life for families of missing persons. Forensic science is used by various other organizations to clarify the fate and whereabouts of persons who have gone missing. Examples include the NGO Argentine Forensic Anthropology Team, working to clarify the fate of people who disappeared during the period of the 1976–1983 military dictatorship. The International Commission on Missing Persons (ICMP) used forensic science to find missing persons, for example after the conflicts in the Balkans. Recognising the role of forensic science for humanitarian purposes, as well as the importance of forensic investigations in fulfilling the state's responsibilities to investigate human rights violations, a group of experts in the late-1980s devised a UN Manual on the Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, which became known as the Minnesota Protocol. This document was revised and re-published by the Office of the High Commissioner for Human Rights in 2016. == See also == Association of Firearm and Tool Mark Examiners – International non-profit organization Canadian Identification Society Computer forensics – Branch of digital forensic science Crime science – study of crime in order to find ways to prevent itPages displaying wikidata descriptions as a fallback Diplomatics – Academic study of the protocols of documents (forensic paleography) Epigenetics in forensic science – Overview article Evidence packaging – Specialized packaging for physical evidence Forensic biology – Forensic application of the study of biology Forensic economics Forensic identification – Legal identification of specific objects and materials Forensic materials engineering – branch of forensic engineeringPages displaying wikidata descriptions as a fallback Forensic photography – Art of producing an accurate reproduction of a crime scene Forensic polymer engineering – Study of failure in polymeric products Forensic profiling – Study of trace evidence in criminal investigations Glove prints – Mark left on a surface by a worn glove History of forensic photography International Association for Identification Marine forensics – legal issues of marine lifePages displaying wikidata descriptions as a fallback Outline of forensic science – Overview of and topical guide to forensic science Profiling (information science) – Process of construction and application of user profiles generated by computerized data analysis Retrospective diagnosis – Practice of identifying an illness after the death of the patient Rapid Stain Identification Series (RSID) Scenes of crime officer – Officer who gathers forensic evidence for the British police Skid mark – Mark left by any solid which moves against another University of Florida forensic science distance education program == References == == Bibliography == == External links == Media related to Forensic science at Wikimedia Commons Forensic educational resources Dunning, Brian (1 March 2022). "Skeptoid #821: Forensic (Pseudo) Science". Skeptoid. Retrieved 15 May 2022.
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https://en.wikipedia.org/wiki/Forensic_science
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Social science (often rendered in the plural as the social sciences) is one of the branches of science, devoted to the study of societies and the relationships among members within those societies. The term was formerly used to refer to the field of sociology, the original "science of society", established in the 18th century. It now encompasses a wide array of additional academic disciplines, including anthropology, archaeology, economics, geography, history, linguistics, management, communication studies, psychology, culturology, and political science. The majority of positivist social scientists use methods resembling those used in the natural sciences as tools for understanding societies, and so define science in its stricter modern sense. Speculative social scientists, otherwise known as interpretivist scientists, by contrast, may use social critique or symbolic interpretation rather than constructing empirically falsifiable theories, and thus treat science in its broader sense. In modern academic practice, researchers are often eclectic, using multiple methodologies (combining both quantitative and qualitative research). To gain a deeper understanding of complex human behavior in digital environments, social science disciplines have increasingly integrated interdisciplinary approaches, big data, and computational tools. The term social research has also acquired a degree of autonomy as practitioners from various disciplines share similar goals and methods. == History == The history of the social sciences began in the Age of Enlightenment after 1651, which saw a revolution within natural philosophy, changing the basic framework by which individuals understood what was scientific. Social sciences came forth from the moral philosophy of the time and were influenced by the Age of Revolutions, such as the Industrial Revolution and the French Revolution. The social sciences developed from the sciences (experimental and applied), or the systematic knowledge-bases or prescriptive practices, relating to the social improvement of a group of interacting entities. The beginnings of the social sciences in the 18th century are reflected in the grand encyclopedia of Diderot, with articles from Jean-Jacques Rousseau and other pioneers. The growth of the social sciences is also reflected in other specialized encyclopedias. The term "social science" was coined in French by Mirabeau in 1767, before becoming a distinct conceptual field in the nineteenth century. Social science was influenced by positivism, focusing on knowledge based on actual positive sense experience and avoiding the negative; metaphysical speculation was avoided. Auguste Comte used the term science sociale to describe the field, taken from the ideas of Charles Fourier; Comte also referred to the field as social physics. Following this period, five paths of development sprang forth in the social sciences, influenced by Comte in other fields. One route that was taken was the rise of social research. Large statistical surveys were undertaken in various parts of the United States and Europe. Another route undertaken was initiated by Émile Durkheim, studying "social facts", and Vilfredo Pareto, opening metatheoretical ideas and individual theories. A third means developed, arising from the methodological dichotomy present, in which social phenomena were identified with and understood; this was championed by figures such as Max Weber. The fourth route taken, based in economics, was developed and furthered economic knowledge as a hard science. The last path was the correlation of knowledge and social values; the antipositivism and verstehen sociology of Max Weber firmly demanded this distinction. In this route, theory (description) and prescription were non-overlapping formal discussions of a subject. The foundation of social sciences in the West implies conditioned relationships between progressive and traditional spheres of knowledge. In some contexts, such as the Italian one, sociology slowly affirms itself and experiences the difficulty of affirming a strategic knowledge beyond philosophy and theology. Around the start of the 20th century, Enlightenment philosophy was challenged in various quarters. After the use of classical theories since the end of the scientific revolution, various fields substituted mathematics studies for experimental studies and examining equations to build a theoretical structure. The development of social science subfields became very quantitative in methodology. The interdisciplinary and cross-disciplinary nature of scientific inquiry into human behaviour, social and environmental factors affecting it, made many of the natural sciences interested in some aspects of social science methodology. Examples of boundary blurring include emerging disciplines like social research of medicine, sociobiology, neuropsychology, bioeconomics and the history and sociology of science. Increasingly, quantitative research and qualitative methods are being integrated in the study of human action and its implications and consequences. In the first half of the 20th century, statistics became a free-standing discipline of applied mathematics. Statistical methods were used confidently. In the contemporary period, Karl Popper and Talcott Parsons influenced the furtherance of the social sciences. Researchers continue to search for a unified consensus on what methodology might have the power and refinement to connect a proposed "grand theory" with the various midrange theories that, with considerable success, continue to provide usable frameworks for massive, growing data banks; for more, see consilience. The social sciences will for the foreseeable future be composed of different zones in the research of, and sometimes distinct in approach toward, the field. The term "social science" may refer either to the specific sciences of society established by thinkers such as Comte, Durkheim, Marx, and Weber, or more generally to all disciplines outside of "noble science" and arts. By the late 19th century, the academic social sciences were constituted of five fields: jurisprudence and amendment of the law, education, health, economy and trade, and art. Around the start of the 21st century, the expanding domain of economics in the social sciences has been described as economic imperialism. A distinction is usually drawn between the social sciences and the humanities. Classicist Allan Bloom writes in The Closing of the American Mind (1987): Social science and humanities have a mutual contempt for one another, the former looking down on the latter as unscientific, the latter regarding the former as philistine. [...] The difference comes down to the fact that social science really wants to be predictive, meaning that man is predictable, while the humanities say that he is not. == Branches == The social science disciplines are branches of knowledge taught and researched at the college or university level. Social science disciplines are defined and recognized by the academic journals in which research is published, and the learned social science societies and academic departments or faculties to which their practitioners belong. Social science fields of study usually have several sub-disciplines or branches, and the distinguishing lines between these are often both arbitrary and ambiguous. The following are widely-considered to be social sciences: === Anthropology === Anthropology is the holistic "science of man", a science of the totality of human existence. The discipline deals with the integration of different aspects of the social sciences, humanities, and human biology. In the twentieth century, academic disciplines have often been institutionally divided into three broad domains. Firstly, the natural sciences seek to derive general laws through reproducible and verifiable experiments. Secondly, the humanities generally study local traditions, through their history, literature, music, and arts, with an emphasis on understanding particular individuals, events, or eras. Finally, the social sciences have generally attempted to develop scientific methods to understand social phenomena in a generalizable way, though usually with methods distinct from those of the natural sciences. The anthropological social sciences often develop nuanced descriptions rather than the general laws derived in physics or chemistry, or they may explain individual cases through more general principles, as in many fields of psychology. Anthropology (like some fields of history) does not easily fit into one of these categories, and different branches of anthropology draw on one or more of these domains. Within the United States, anthropology is divided into four sub-fields: archaeology, physical or biological anthropology, anthropological linguistics, and cultural anthropology. It is an area that is offered at most undergraduate institutions. The word anthropos (ἄνθρωπος) in Ancient Greek means "human being" or "person". Eric Wolf described sociocultural anthropology as "the most scientific of the humanities, and the most humanistic of the sciences". The goal of anthropology is to provide a holistic account of humans and human nature. This means that, though anthropologists generally specialize in only one sub-field, they always keep in mind the biological, linguistic, historic and cultural aspects of any problem. Since anthropology arose as a science in Western societies that were complex and industrial, a major trend within anthropology has been a methodological drive to study peoples in societies with more simple social organization, sometimes called "primitive" in anthropological literature, but without any connotation of "inferior". Today, anthropologists use terms such as "less complex" societies or refer to specific modes of subsistence or production, such as "pastoralist" or "forager" or "horticulturalist" to refer to humans living in non-industrial, non-Western cultures, such people or folk (ethnos) remaining of great interest within anthropology. The quest for holism leads most anthropologists to study a people in detail, using biogenetic, archaeological, and linguistic data alongside direct observation of contemporary customs. In the 1990s and 2000s, calls for clarification of what constitutes a culture, of how an observer knows where his or her own culture ends and another begins, and other crucial topics in writing anthropology were heard. It is possible to view all human cultures as part of one large, evolving global culture. These dynamic relationships, between what can be observed on the ground, as opposed to what can be observed by compiling many local observations remain fundamental in any kind of anthropology, whether cultural, biological, linguistic or archaeological. === Communication studies === Communication studies deals with processes of human communication, commonly defined as the sharing of symbols to create meaning. The discipline encompasses a range of topics, from face-to-face conversation to mass media outlets such as television broadcasting. Communication studies also examine how messages are interpreted through the political, cultural, economic, and social dimensions of their contexts. Communication is institutionalized under many different names at different universities, including communication, communication studies, speech communication, rhetorical studies, communication science, media studies, communication arts, mass communication, media ecology, and communication and media science. Communication studies integrate aspects of both social sciences and the humanities. As a social science, the discipline often overlaps with sociology, psychology, anthropology, biology, political science, economics, and public policy, among others. From a humanities perspective, communication is concerned with rhetoric and persuasion (traditional graduate programs in communication studies trace their history to the rhetoricians of Ancient Greece). The field applies to outside disciplines as well, including engineering, architecture, mathematics, and information science. === Economics === Economics is a social science that seeks to analyze and describe the production, distribution, and consumption of wealth. The word "economics" is from the Ancient Greek οἶκος (oikos, "family, household, estate") and νόμος (nomos, "custom, law"), and hence means "household management" or "management of the state". An economist is a person using economic concepts and data in the course of employment, or someone who has earned a degree in the subject. The classic brief definition of economics, set out by Lionel Robbins in 1932, is "the science which studies human behavior as a relationship between ends and scarce means which have alternative uses". Without scarcity and alternative uses, there is no economic problem. Briefer yet is "the study of how people seek to satisfy needs and wants" and "the study of the financial aspects of human behavior". Economics has two broad branches: microeconomics, where the unit of analysis is the individual agent, such as a household or firm, and macroeconomics, where the unit of analysis is an economy as a whole. Another division of the subject distinguishes positive economics, which seeks to predict and explain economic phenomena, from normative economics, which orders choices and actions by some criterion; such orderings necessarily involve subjective value judgments. Since the early part of the 20th century, economics has focused largely on measurable quantities, employing both theoretical models and empirical analysis. Quantitative models, however, can be traced as far back as the physiocratic school. Economic reasoning has been increasingly applied in recent decades to other social situations such as politics, law, psychology, history, religion, marriage and family life, and other social interactions. The expanding domain of economics in the social sciences has been described as economic imperialism. === Education === Education encompasses teaching and learning specific skills, and also something less tangible but more profound: the imparting of knowledge, positive judgement and well-developed wisdom. Education has as one of its fundamental aspects the imparting of culture from generation to generation (see socialization). To educate means 'to draw out', from the Latin educare, or to facilitate the realization of an individual's potential and talents. It is an application of pedagogy, a body of theoretical and applied research relating to teaching and learning and draws on many disciplines such as psychology, philosophy, computer science, linguistics, neuroscience, sociology and anthropology. === Geography === Geography as a discipline can be split broadly into two main sub fields: human geography and physical geography. The former focuses largely on the built environment and how space is created, viewed and managed by humans as well as the influence humans have on the space they occupy. This may involve cultural geography, transportation, health, military operations, and cities. The latter examines the natural environment and how the climate, vegetation and life, soil, oceans, water and landforms are produced and interact (is also commonly regarded as an Earth Science). Physical geography examines phenomena related to the measurement of earth. As a result of the two subfields using different approaches a third field has emerged, which is environmental geography. Environmental geography combines physical and human geography and looks at the interactions between the environment and humans. Other branches of geography include social geography, regional geography, and geomatics. Geographers attempt to understand the Earth in terms of physical and spatial relationships. The first geographers focused on the science of mapmaking and finding ways to precisely project the surface of the earth. In this sense, geography bridges some gaps between the natural sciences and social sciences. Historical geography is often taught in a college in a unified Department of Geography. Modern geography is an all-encompassing discipline, closely related to Geographic Information Science, that seeks to understand humanity and its natural environment. The fields of urban planning, regional science, and planetology are closely related to geography. Practitioners of geography use many technologies and methods to collect data such as Geographic Information Systems, remote sensing, aerial photography, statistics, and global positioning systems. === History === History is the continuous, systematic narrative and research into past human events as interpreted through historiographical paradigms or theories. When used as the name of a field of study, history refers to the study and interpretation of the record of humans, societies, institutions, and any topic that has changed over time. Traditionally, the study of history has been considered a part of the humanities. In modern academia, whether or not history remains a humanities-based subject is contested. In the United States the National Endowment for the Humanities includes history in its definition of humanities (as it does for applied linguistics). However, the National Research Council classifies history as a social science. The historical method comprises the techniques and guidelines by which historians use primary sources and other evidence to research and then to write history. The Social Science History Association, formed in 1976, brings together scholars from numerous disciplines interested in social history. === Law === The social science of law, jurisprudence, in common parlance, means a rule that (unlike a rule of ethics) is capable of enforcement through institutions. However, many laws are based on norms accepted by a community and thus have an ethical foundation. The study of law crosses the boundaries between the social sciences and humanities, depending on one's view of research into its objectives and effects. Law is not always enforceable, especially in the international relations context. It has been defined as a "system of rules", as an "interpretive concept" to achieve justice, as an "authority" to mediate people's interests, and even as "the command of a sovereign, backed by the threat of a sanction". However one likes to think of law, it is a completely central social institution. Legal policy incorporates the practical manifestation of thinking from almost every social science and the humanities. Laws are politics, because politicians create them. Law is philosophy, because moral and ethical persuasions shape their ideas. Law tells many of history's stories, because statutes, case law and codifications build up over time. And law is economics, because any rule about contract, tort, property law, labour law, company law and many more can have long-lasting effects on the distribution of wealth. The noun law derives from the Old English lagu, meaning something laid down or fixed and the adjective legal comes from the Latin word lex. === Linguistics === Linguistics investigates the cognitive and social aspects of human language. The field is divided into areas that focus on aspects of the linguistic signal, such as syntax (the study of the rules that govern the structure of sentences), semantics (the study of meaning), morphology (the study of the structure of words), phonetics (the study of speech sounds) and phonology (the study of the abstract sound system of a particular language); however, work in areas like evolutionary linguistics (the study of the origins and evolution of language) and psycholinguistics (the study of psychological factors in human language) cut across these divisions. The overwhelming majority of modern research in linguistics takes a predominantly synchronic perspective (focusing on language at a particular point in time), and a great deal of it—partly owing to the influence of Noam Chomsky—aims at formulating theories of the cognitive processing of language. However, language does not exist in a vacuum, or only in the brain, and approaches like contact linguistics, creole studies, discourse analysis, social interactional linguistics, and sociolinguistics explore language in its social context. Sociolinguistics often makes use of traditional quantitative analysis and statistics in investigating the frequency of features, while some disciplines, like contact linguistics, focus on qualitative analysis. While certain areas of linguistics can thus be understood as clearly falling within the social sciences, other areas, like acoustic phonetics and neurolinguistics, draw on the natural sciences. Linguistics draws only secondarily on the humanities, which played a rather greater role in linguistic inquiry in the 19th and early 20th centuries. Ferdinand Saussure was one of the founders of 20th century linguistics. === Political science === Political science is an academic and research discipline that deals with the theory and practice of politics and the description and analysis of political systems and political behaviour. Fields and subfields of political science include political economy, political theory and philosophy, civics and comparative politics, theory of direct democracy, apolitical governance, participatory direct democracy, national systems, cross-national political analysis, political development, international relations, foreign policy, international law, politics, public administration, administrative behaviour, public law, judicial behaviour, and public policy. Political science also studies power in international relations and the theory of great powers and superpowers. Political science is methodologically diverse, although recent years have witnessed an upsurge in the use of the scientific method, that is, the proliferation of formal-deductive model building and quantitative hypothesis testing. Approaches to the discipline include rational choice, classical political philosophy, interpretivism, structuralism, and behaviouralism, realism, pluralism, and institutionalism. Political science, as one of the social sciences, uses methods and techniques that relate to the kinds of inquiries sought: primary sources such as historical documents, interviews, and official records, as well as secondary sources such as scholarly articles, are used in building and testing theories. Empirical methods include survey research, statistical analysis or econometrics, case studies, experiments, and model building. === Psychology === Psychology is an academic and applied field involving the study of behaviour and mental processes. Psychology also refers to the application of such knowledge to various spheres of human activity, including problems of individuals' daily lives and the treatment of mental illness. The word psychology comes from the Ancient Greek ψυχή (psyche, "soul" or "mind") and the suffix logy ("study"). Psychology differs from anthropology, economics, political science, and sociology in seeking to capture explanatory generalizations about the mental function and overt behaviour of individuals, while the other disciplines focus on creating descriptive generalizations about the functioning of social groups or situation-specific human behaviour. In practice, however, there is quite a lot of cross-fertilization that takes place among the various fields. Psychology differs from biology and neuroscience in that it is primarily concerned with the interaction of mental processes and behaviour, and of the overall processes of a system, and not simply the biological or neural processes themselves, though the subfield of neuropsychology combines the study of the actual neural processes with the study of the mental effects they have subjectively produced. Many people associate psychology with clinical psychology, which focuses on assessment and treatment of problems in living and psychopathology. In reality, psychology has myriad specialties including social psychology, developmental psychology, cognitive psychology, educational psychology, industrial-organizational psychology, mathematical psychology, neuropsychology, and quantitative analysis of behaviour. Psychology is a very broad science that is rarely tackled as a whole, major block. Although some subfields encompass a natural science base and a social science application, others can be clearly distinguished as having little to do with the social sciences or having a lot to do with the social sciences. For example, biological psychology is considered a natural science with a social scientific application (as is clinical medicine), social and occupational psychology are, generally speaking, purely social sciences, whereas neuropsychology is a natural science that lacks application out of the scientific tradition entirely. In British universities, emphasis on what tenet of psychology a student has studied and/or concentrated is communicated through the degree conferred: BPsy indicates a balance between natural and social sciences, BSc indicates a strong (or entire) scientific concentration, whereas a BA underlines a majority of social science credits. This is not always necessarily the case however, and in many UK institutions students studying the BPsy, BSc, and BA follow the same curriculum as outlined by The British Psychological Society and have the same options of specialism open to them regardless of whether they choose a balance, a heavy science basis, or heavy social science basis to their degree. If they applied to read the BA. for example, but specialized in heavily science-based modules, then they will still generally be awarded the BA. === Sociology === Sociology is the systematic study of society, individuals' relationship to their societies, the consequences of difference, and other aspects of human social action. The meaning of the word comes from the suffix -logy, which means "study of", derived from Ancient Greek, and the stem soci-, which is from the Latin word socius, meaning "companion", or society in general. Auguste Comte (1798–1857) coined the term sociology to describe a way to apply natural science principles and techniques to the social world in 1838. Comte endeavoured to unify history, psychology and economics through the descriptive understanding of the social realm. He proposed that social ills could be remedied through sociological positivism, an epistemological approach outlined in The Course in Positive Philosophy [1830–1842] and A General View of Positivism (1844). Though Comte is generally regarded as the "Father of Sociology", the discipline was formally established by another French thinker, Émile Durkheim (1858–1917), who developed positivism as a foundation to practical social research. Durkheim set up the first European department of sociology at the University of Bordeaux in 1895, publishing his Rules of the Sociological Method. In 1896, he established the journal L'Année sociologique. Durkheim's seminal monograph, Suicide (1897), a case study of suicide rates among Catholic and Protestant populations, distinguished sociological analysis from psychology or philosophy. Karl Marx rejected Comte's positivism but nevertheless aimed to establish a science of society based on historical materialism, becoming recognized as a founding figure of sociology posthumously as the term gained broader meaning. Around the start of the 20th century, the first wave of German sociologists, including Max Weber and Georg Simmel, developed sociological antipositivism. The field may be broadly recognized as an amalgam of three modes of social thought in particular: Durkheimian positivism and structural functionalism; Marxist historical materialism and conflict theory; and Weberian antipositivism and verstehen analysis. American sociology broadly arose on a separate trajectory, with little Marxist influence, an emphasis on rigorous experimental methodology, and a closer association with pragmatism and social psychology. In the 1920s, the Chicago school developed symbolic interactionism. Meanwhile, in the 1930s, the Frankfurt School pioneered the idea of critical theory, an interdisciplinary form of Marxist sociology drawing upon thinkers as diverse as Sigmund Freud and Friedrich Nietzsche. Critical theory would take on something of a life of its own after World War II, influencing literary criticism and the Birmingham School establishment of cultural studies. Sociology evolved as an academic response to the challenges of modernity, such as industrialization, urbanization, secularization, and a perceived process of enveloping rationalization. The field generally concerns the social rules and processes that bind and separate people not only as individuals, but as members of associations, groups, communities and institutions, and includes the examination of the organization and development of human social life. The sociological field of interest ranges from the analysis of short contacts between anonymous individuals on the street to the study of global social processes. In the terms of sociologists Peter L. Berger and Thomas Luckmann, social scientists seek an understanding of the Social Construction of Reality. Most sociologists work in one or more subfields. One useful way to describe the discipline is as a cluster of sub-fields that examine different dimensions of society. For example, social stratification studies inequality and class structure; demography studies changes in population size or type; criminology examines criminal behaviour and deviance; and political sociology studies the interaction between society and state. Since its inception, sociological epistemologies, methods, and frames of enquiry, have significantly expanded and diverged. Sociologists use a diversity of research methods, collecting both quantitative and qualitative data, draw upon empirical techniques, and engage critical theory. Common modern methods include case studies, historical research, interviewing, participant observation, social network analysis, survey research, statistical analysis, and model building, among other approaches. Since the late 1970s, many sociologists have tried to make the discipline useful for purposes beyond the academy. The results of sociological research aid educators, lawmakers, administrators, developers, and others interested in resolving social problems and formulating public policy, through subdisciplinary areas such as evaluation research, methodological assessment, and public sociology. In the early 1970s, women sociologists began to question sociological paradigms and the invisibility of women in sociological studies, analysis, and courses. In 1969, feminist sociologists challenged the discipline's androcentrism at the American Sociological Association's annual conference. This led to the founding of the organization Sociologists for Women in Society, and, eventually, a new sociology journal, Gender & Society. Today, the sociology of gender is considered to be one of the most prominent sub-fields in the discipline. New sociological sub-fields continue to appear — such as community studies, computational sociology, environmental sociology, network analysis, actor-network theory, gender studies, and a growing list, many of which are cross-disciplinary in nature. == Additional fields of study == Additional applied or interdisciplinary fields related to the social sciences or are applied social sciences include: Archaeology, a science that is focused on the study of human cultures by means of the recovery, documentation, analysis, and interpretation of material remains and environmental data, including architecture, artifacts, features, and landscapes. Area studies, interdisciplinary fields of research and scholarship pertaining to particular geographical, national/federal, or cultural regions. Behavioural science, which encompasses disciplines that explore the activities of and interactions among organisms in the natural world. Computational social science, an umbrella field encompassing computational approaches within the social sciences. Demography, the statistical study of human populations. Development studies, a branch of social science that addresses issues of concern to developing countries. Environmental social science, the broad study of interrelations between humans and the natural environment. Environmental studies, which integrates social, humanistic, and natural science perspectives on the relation between humans and the natural environment. Gender studies, which is focused on the study of gender identity, masculinity, femininity, transgender issues, and sexuality. Information science, an interdisciplinary science primarily concerned with the collection, classification, manipulation, storage, retrieval and dissemination of information. International studies, which covers both international relations (the study of foreign affairs and global issues among states within the international system) and international education. Legal management, a social sciences discipline that is designed for students interested in the study of state and legal elements. Library science, a field that applies the practices, perspectives, and tools of management, information technology, education, and other areas to libraries; and the collection, organization, preservation and dissemination of information resources. Management, which consists of various levels of leadership and administration of an organization in all business and human organizations. It is the effective execution of getting people together to accomplish desired goals and objectives through adequate planning, executing and controlling activities. Marketing, the identification of human needs and wants, defines and measures their magnitude for demand and understanding the process of consumer buying behaviour to formulate products and services, pricing, promotion and distribution to satisfy these needs and wants through exchange processes and building long-term relationships. Political economy, the study of production, buying and selling, and their relations with law, custom, and government. Public administration, the development, implementation and study of branches of government policy. Though public administration has been historically referred to as government management, it increasingly encompasses non-governmental organizations (NGOs) that also operate with a similar, primary dedication to the betterment of humanity. Religious studies and Western esoteric studies, which incorporate social-scientific research on phenomena deemed religious. == Methodology == === Social research === The origin of the survey can be traced back at least as early as the Domesday Book in 1086, while some scholars pinpoint the origin of demography to 1663 with the publication of John Graunt's Natural and Political Observations upon the Bills of Mortality. Social research began most intentionally, however, with the positivist philosophy of science in the 19th century. In contemporary usage, "social research" is a relatively autonomous term, encompassing the work of practitioners from various disciplines that share in its aims and methods. Social scientists employ a range of methods in order to analyse a vast breadth of social phenomena; from census survey data derived from millions of individuals, to the in-depth analysis of a single agent's social experiences; from monitoring what is happening on contemporary streets, to the investigation of ancient historical documents. The methods originally rooted in classical sociology and statistical mathematics have formed the basis for research in other disciplines, such as political science, media studies, and marketing and market research. Social research methods may be divided into two broad schools: Quantitative designs approach social phenomena through quantifiable evidence, and often rely on statistical analysis of many cases (or across intentionally designed treatments in an experiment) to create valid and reliable general claims. Qualitative designs emphasize understanding of social phenomena through direct observation, communication with participants, or analysis of texts, and may stress contextual and subjective accuracy over generality. Social scientists will commonly combine quantitative and qualitative approaches as part of a multi-strategy design. Questionnaires, field-based data collection, archival database information and laboratory-based data collections are some of the measurement techniques used. It is noted the importance of measurement and analysis, focusing on the (difficult to achieve) goal of objective research or statistical hypothesis testing. A mathematical model uses mathematical language to describe a system. The process of developing a mathematical model is termed 'mathematical modelling' (also modeling). A mathematical model is "a representation of the essential aspects of an existing system (or a system to be constructed) that presents knowledge of that system in usable form". Mathematical models can take many forms, including but not limited to dynamical systems, statistical models, differential equations, or game theoretic models. These and other types of models can overlap, with a given model involving a variety of abstract structures. The system is a set of interacting or interdependent entities, real or abstract, forming an integrated whole. The concept of an integrated whole can also be stated in terms of a system embodying a set of relationships that are differentiated from relationships of the set to other elements, and from relationships between an element of the set and elements not a part of the relational regime. A dynamical system modeled as a mathematical formalization has a fixed "rule" that describes the time dependence of a point's position in its ambient space. Small changes in the state of the system correspond to small changes in the numbers. The evolution rule of the dynamical system is a fixed rule that describes what future states follow from the current state. The rule is deterministic: for a given time interval only one future state follows from the current state. Social scientists often conduct program evaluation, which is a systematic method for collecting, analyzing, and using information to answer questions about projects, policies and programs, particularly about their effectiveness and efficiency. In both the public and private sectors, stakeholders often want to know whether the programs they are funding, implementing, voting for, receiving or objecting to are producing the intended effect. While program evaluation first focuses around this definition, important considerations often include how much the program costs per participant, how the program could be improved, whether the program is worthwhile, whether there are better alternatives, if there are unintended outcomes, and whether the program goals are appropriate and useful. === Theory === Some social theorists emphasize the subjective nature of research. These writers espouse social theory perspectives that include various types of the following: Critical theory is the examination and critique of society and culture, drawing from knowledge across social sciences and humanities disciplines. Dialectical materialism is the philosophy of Karl Marx, which he formulated by taking the dialectic of Hegel and joining it to the materialism of Feuerbach. Feminist theory is the extension of feminism into theoretical, or philosophical discourse; it aims to understand the nature of gender inequality. Marxist theories, such as revolutionary theory, scientific socialism, and class theory, cover work in philosophy that is strongly influenced by Karl Marx's materialist approach to theory or is written by Marxists. Phronetic social science is a theory and methodology for doing social science focusing on ethics and political power, based on a contemporary interpretation of Aristotelian phronesis. Post-colonial theory is a reaction to the cultural legacy of colonialism. Postmodernism refers to a point of departure for works of literature, drama, architecture, cinema, and design, as well as in marketing and business and in the interpretation of history, law, culture and religion in the late 20th century. Rational choice theory is a framework for understanding and often formally modeling social and economic behaviour. Social constructionism considers how social phenomena develop in social contexts. Structuralism is an approach to the human sciences that attempts to analyze a specific field (for instance, mythology) as a complex system of interrelated parts. Structural functionalism is a sociological paradigm that addresses what social functions various elements of the social system perform in regard to the entire system. Other fringe social theorists delve into the alternative nature of research. These writers share social theory perspectives that include various types of the following: Anti-intellectualism describes a sentiment of critique towards, or evaluation of, intellectuals and intellectual pursuits. Antiscience is a position critical of science and the scientific method. === Recursivity === Authors use the concept of recursivity to foreground the situation in which social scientists find themselves when producing knowledge about the world they are always already part of. According to Audrey Alejandro, "as social scientists, the recursivity of our condition deals with the fact that we are both subjects (as discourses are the medium through which we analyse) and objects of the academic discourses we produce (as we are social agents belonging to the world we analyse)." From this basis, she identifies in recursivity a fundamental challenge in the production of emancipatory knowledge which calls for the exercise of reflexive efforts: we are socialised into discourses and dispositions produced by the socio-political order we aim to challenge, a socio-political order that we may, therefore, reproduce unconsciously while aiming to do the contrary. The recursivity of our situation as scholars – and, more precisely, the fact that the dispositional tools we use to produce knowledge about the world are themselves produced by this world – both evinces the vital necessity of implementing reflexivity in practice and poses the main challenge in doing so. == Education and degrees == Most universities offer degrees in social science fields. The Bachelor of Social Science is a degree targeted at the social sciences in particular, it is often more flexible and in-depth than other degrees that include social science subjects. In the United States, a university may offer a student who studies a social sciences field a Bachelor of Arts degree, particularly if the field is within one of the traditional liberal arts such as history, or a BSc: Bachelor of Science degree such as those given by the London School of Economics, as the social sciences constitute one of the two main branches of science (the other being the natural sciences). In addition, some institutions have degrees for a particular social science, such as the Bachelor of Economics degree, though such specialized degrees are relatively rare in the United States. Graduate students may receive a master's degree (Master of Arts, Master of Science or a field-specific degree such as Master of Public Administration) or a doctoral degree (e.g. PhD). == Funding == The funding of social science programs varies across countries and includes both private and public financing. The development of such programs typically see an increased funding and attention when their topics coincide with national political activities or economic policies. In South America, namely Brazil, the institutionalisation of social sciences took place in a political context where the state struggled to assert its territorial power, and the social scientific field was expected to produce investigation but also political inputs towards the construction of a new nation. Immediately following the 1932 Brazilian revolution, social science programs experience a surge in funding, later becoming the largest of such capital expenditure in South America. Subsequently, these developments led to the deployment of university programs and the institution of national associations in anthropology, economics, sociology and political science. == People associated with the social sciences == == See also == == Notes == == References == == Bibliography == Michie, Jonathan, ed. Reader's Guide to the Social Sciences (2 vol. 2001) 1970 pages annotating the major topics in the late 20th century in all the social sciences. === 20th and 21st centuries sources === Neil J. Smelser and Paul B. Baltes (2001). International Encyclopedia of the Social & Behavioral Sciences, Amsterdam: Elsevier. Byrne, D.S. (1998). Complexity theory and the social sciences: an introduction. Routledge. ISBN 978-0-415-16296-8 Kuper, A., and Kuper, J. (1985). The Social Science Encyclopedia. London: Routledge & Kegan Paul. (ed., a limited preview of the 1996 version is available) Lave, C.A., and March, J.G. (1993). An introduction to models in the social sciences. Lanham, Md: University Press of America. Perry, John and Erna Perry. Contemporary Society: An Introduction to Social Science (12th Edition, 2008), college textbook Potter, D. (1988). Society and the social sciences: An introduction. London: Routledge [u.a.]. David L. Sills and Robert K. Merton (1968). International Encyclopedia of the Social Sciences. Seligman, Edwin R.A. and Alvin Johnson (1934). Encyclopedia of the Social Sciences. (13 vol.) Ward, L.F. (1924). Dynamic sociology, or applied social science: As based upon statical sociology and the less complex sciences. New York: D. Appleton. Leavitt, F.M., and Brown, E. (1920). Elementary social science. New York: Macmillan. Bogardus, E.S. (1913). Introduction to the social sciences: A textbook outline. Los Angeles: Ralston Press. Small, A.W. (1910). The meaning of social science. Chicago: The University of Chicago Press. === 19th century sources === Andrews, S.P. (1888). The science of society. Boston, Mass: Sarah E. Holmes. Denslow, V.B. (1882). Modern thinkers principally upon social science: What they think, and why. Chicago: Belford, Clarke & Co. Harris, William Torrey (1879). Method of Study in Social Science: A Lecture Delivered Before the St. Louis Social Science Association, March 4, 1879. St. Louis: G.I. Jones and Co, 1879. Hamilton, R.S. (1873). Present status of social science. A review, historical and critical, of the progress of thought in social philosophy. New York: H.L. Hinton. Carey, H.C. (1867). Principles of social science. Philadelphia: J.B. Lippincott & Co. [etc.]. Volume I, Volume II, Volume III. Calvert, G.H. (1856). Introduction to social science: A discourse in three parts. New York: Redfield. === General sources === Backhouse, Roger E., and Philippe Fontaine, eds. A historiography of the modern social sciences (Cambridge University Press, 2014). Backhouse, Roger E.; Fontaine, Philippe, eds. (2010). The History of the Social Sciences Since 1945. Cambridge University Press.; covers the conceptual, institutional, and wider histories of economics, political science, sociology, social anthropology, psychology, and human geography. Delanty, G. (1997). Social science: Beyond constructivism and realism. Minneapolis: Univ. of Minnesota Press. Hargittai, E. (2009). Research Confidential: Solutions to Problems Most Social Scientists Pretend They Never Have. Ann Arbor: University of Michigan Press. ISBN 978-0472026531. Heim, K. M. (1987). Social Scientific Information Needs for Numeric Data: The Evolution of the International Data Archive Infrastructure. Collection Management, 9(1), 1–53. Hunt, E.F.; Colander, D.C. (2008). Social science: An introduction to the study of society. Boston: Peason/Allyn and Bacon. ISBN 978-0-205-52406-8. Carey, H.C.; McKean, K. (1883). Manual of social science; Being a condensation of the Principles of social science. Philadelphia: Baird. Galavotti, M.C. (2003). Observation and experiment in the natural and social sciences. Boston studies in the philosophy of science. Vol. 232. Dordrecht: Kluwer Academic. ISBN 978-1-4020-1251-8. Gorton, W.A. (2006). Karl Popper and the social sciences. SUNY series in the philosophy of the social sciences. Albany: State University of New York Press. Harris, F.R. (1973). Social science and national policy. New Brunswick, N.J.: Transaction Books. ISBN 978-1-4128-3445-2. distributed by Dutton Krimerman, L.I. (1969). The nature and scope of social science: A critical anthology. New York: Appleton-Century-Crofts. ISBN 978-0-390-52678-6. Rule, J.B. (1997). Theory and progress in social science. Cambridge: Cambridge University Press. ISBN 978-0-521-57365-8. Shionoya, Y. (1997). Schumpeter and the idea of social science: A metatheoretical study. Historical perspectives on modern economics. Cambridge: Cambridge University Press. Singleton, Royce, A.; Straits, Bruce C. (1988). Approaches to Social Research. Oxford University Press. ISBN 978-0-19-514794-0. Archived from the original on March 3, 2007.{{cite book}}: CS1 maint: multiple names: authors list (link) Thomas, D. (1979). Naturalism and social science: a post-empiricist philosophy of social science. CUP Archive. ISBN 978-0-521-29660-1. Trigg, R. (2001). Understanding social science: A philosophical introduction to the social sciences. Malden, Mass: Blackwell Publishers. Weber, M. (1906) [1904]. The Relations of the Rural Community to Other Branches of Social Science, Congress of Arts and Science: Universal Exposition. St. Louis: Houghton, Mifflin and Company. Creswell, John W. Educational research: planning, conducting, and evaluating quantitative and qualitative research. ISBN 978-1-299-95719-0. OCLC 859836343. === Academic resources === The Annals of the American Academy of Political and Social Science, ISSN 1552-3349 (electronic) ISSN 0002-7162 (paper), Sage Publications Efferson, Charles; Richerson, Peter J. (March 16, 2007). "A prolegomenon to nonlinear empiricism in the human behavioral sciences". Biology & Philosophy. 22 (1): 1–33. doi:10.1007/s10539-005-9013-7. === Opponents and critics === George H. Smith (2014). Intellectuals and Libertarianism: Thomas Sowell and Robert Nisbet Phil Hutchinson, Rupert Read and Wes Sharrock (2008). There's No Such Thing as a Social Science. ISBN 978-0-7546-4776-8 Sabia, D.R., and Wallulis, J. (1983). Changing social science: Critical theory and other critical perspectives. Albany: State University of New York Press. == External links == Institute for Comparative Research in Human and Social Sciences (ICR) (JAPAN) Centre for Social Work Research International Conference on Social Sciences International Social Science Council Introduction to Hutchinson et al., There's No Such Thing as a Social Science Intute: Social Sciences (UK) Social Science Research Society Social Science Virtual Library Social Science Virtual Library: Canaktanweb (Turkish) Social Sciences And Humanities UC Berkeley Experimental Social Science Laboratory The Dialectic of Social Science by Paul A. Baran American Academy Commission on the Humanities and Social Sciences
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The New Science (Italian: La Scienza Nuova pronounced [la ʃˈʃɛntsa ˈnwɔːva]) is the major work of Italian philosopher Giambattista Vico. It was first published in 1725 to little success, but has gone on to be highly regarded and influential in the philosophy of history, sociology, and anthropology. The central concepts were highly original and prefigured the Age of Enlightenment. == Titles == The full title of the 1725 edition was Principj di una Scienza Nuova Intorno alla Natura delle Nazioni per la Quale si Ritruovano i Principj di Altro Sistema del Diritto Naturale delle Genti, ending with a dedication to Cardinal Lorenzo Corsini, the future Pope Clement XII. Principj and ritruovano being archaic spellings of principi and ritrovano, the title may be loosely translated "Principles of a New Science Concerning the Nature of Nations, through Which Are Recovered the Principles of Another System of the Natural Law of Peoples". The 1730 edition was titled Cinque Libri di Giambattista Vico de' Principj d' una Scienza Nuova d'Intorno alla Comune Natura della Nazioni ("Giambattista Vico's Five Books on the Principles of a New Science Concerning Nations' Shared Nature"), ending with a dedication to Clement XII. The 1744 edition was slightly emended to Principj di Scienza Nuova di Giambattista Vico d'Intorno alla Comune Natura delle Nazioni ("Giambattista Vico's Principles of New Science Concerning Nations' Shared Nature"), without a title page dedication. Clement had died in 1740 and Vico in 1744, before the edition's publication. == Creation == In 1720, Vico began work on the Scienza Nuova as part of a treatise on universal rights. Although it was originally supposed to be sponsored by Cardinal Corsini, Vico was forced to finance the publication himself after the cardinal pleaded financial difficulty and withdrew his patronage. It was the first work by Vico to be written in Italian, since his previous ones had been in Latin. The first edition of the New Science appeared in 1725. Vico worked on two heavily revised editions. The first was published in 1730, the second posthumously in 1744. == Approach, style and tone == In its first section, titled "Idea of the Work" (Idea dell'Opera), the 1730 and 1744 editions of The New Science explicitly present themselves as a "science of reasoning" (scienza di ragionare). The work (especially the section "Of the Elements") includes a dialectic between axioms (authoritative maxims or degnità) and "reasonings" (ragionamenti) linking and clarifying the axioms. Vico began the third edition with a detailed close reading of a front piece portrait, examining the place of Gentile nations within the providential guidance of the Hebrew God. This portrait contains a number of images that are symbolically ascribed to the flow of human history. A triangle with the Eye of Providence appears in the top left. A beam of light from the eye shines upon a brooch attached to the breastplate of “the lady with the winged temples who surmounts the celestial globe or world of nature” (center right), which represents metaphysics. The beam reflects off the brooch onto the back of a robed character standing upon a pedestal (bottom left), representing the poet Homer. All around these main characters resides a variety of objects that represent the stages of human history which Vico categorizes into three epochs: the age of the gods “in which the gentiles believed they lived under divine governments, and everything was commanded them by auspices and oracles, which are the oldest institutions in profane history; the age of the heroes "in which they reigned everywhere in aristocratic commonwealths, on account of a certain superiority of nature which they held themselves to have over the plebs (or peasants);" and the age of men "in which all men recognized themselves as equal in human nature, and therefore there were established first the popular commonwealths and then the monarchies, both of which are forms of human government." By viewing these principles as universal phenomena which combined nature and government with language and philology, Vico could insert the history of the Gentile nations into the supreme guidance by divine providence. According to Vico, the proper end for government resulted with society entering into a state of universal equity: "The last type of jurisprudence was that of natural equity, which reigns naturally in the free commonwealths, in which the people, each for his own particular good (without understanding that it is the same for all), are led to command universal laws. They naturally desire these laws to bend benignly to the least details of matters calling for equal unity." Vico specifies that his "science" reasons primarily about the function of religion in the human world ("Idea of the Work"), and in this respect the work "comes to be a civil theology reasoned from divine providence" (vien ad essere una teologia civile ragionata della provvidenza divina). Reconsidering divine providence within a human or political context, Vico unearths the "poetic theologians" (poeti teologi) of pagan antiquity, exposing the poetic character of theology independently of Christianity's sacred history and thus of Biblical authority. Vico's use of poetic theology, anticipated in his 1710 work De Antiquissima Italorum Sapientia ("On the Ancient Wisdom of the Italians"), confirms his ties to the Italian Renaissance and its own appeals to theologia poetica. With the early Renaissance, Vico shares the call for recovering a "pagan" or "vulgar" horizon for philosophy's providential agency or for recognizing the providence of our human "metaphysical" minds (menti) in the world of our "political" wills (animi). "Poetic theology" would serve as stage for an "ascent" to recognize the inherence or latency of rational agency in our actions, even when these are brutal. This way, the particular providence of the Bible's "true God" would not be required for the thriving of properly human life. All that would be needed was (A) false religions and false gods and (B) the covert work of the conatus (the rational principle of a constitution of experience rooted in its proper infinite form), which was examined at length in De Antiquissima Italorum Sapientia and evoked again in the section "Of the Method" in the 1730 and 1744 editions of The New Science. == Cyclical history (Corsi e ricorsi) == Vico is often seen as espousing a cyclical history where human history is created by man, although Vico never speaks of "history without attributes" (Paolo Cristofolini, Vice Pagano e Barbaro), but of a "world of nations". Which is more, in the 1744 Scienza Nuova (esp. the "Conclusion of the Work") Vico stresses that "the world of nations" is made by men merely with respect to their sense of certainty (certamente), though not fundamentally, insofar as the world is guided by the human mind "metaphysically" independent of its makings (compare opening paragraph of the Scienza Nuova). Furthermore, although Vico is often attributed the expression "corsi e ricorsi" (cycles and counter cycles of growth and decay) of "history", he never speaks in the plural of "the cycle" or of "the counter-cycle" (ricorso) of "human things", suggesting that political life and order, or human creations, are oriented "backward," as it were, or called back to their constitutive "metaphysical" principle. On present day "constructivist" readings, Vico is supposed to have promoted a vision of man and society as moving in parallel from barbarism to civilization.As societies become more developed socially, human nature also develops, and both manifest their development in changes in language, myth, folklore, economy, etc.; in short, social change produces cultural change.Vico would therefore be using an original organic idea that culture is a system of socially produced and structured elements. Hence, knowledge of any society would come from the social structure of that society, explicable, therefore, only in terms of its own language. As such, one may find a dialectical relationship between language, knowledge and social structure. Relying on a complex etymology, Vico argues in the Scienza Nuova that civilization develops in a recurring cycle (ricorso) of three ages: the divine, the heroic, and the human. Each age exhibits distinct political and social features and can be characterized by master tropes or figures of language. The giganti of the divine age rely on metaphor to compare, and thus comprehend, human and natural phenomena. In the heroic age, metonymy and synecdoche support the development of feudal or monarchic institutions embodied by idealized figures. The final age is characterized by popular democracy and reflection via irony; in this epoch, the rise of rationality leads to barbarie della reflessione or barbarism of reflection, and civilization descends once more into the poetic era. Taken together, the recurring cycle of three ages – common to every nation – constitutes for Vico a storia ideale eterna or ideal eternal history. Therefore, it can be said that all history is the history of the rise and fall of civilizations, for which Vico provides evidence (up until, and including the Graeco-Roman historians). == Ideas on rhetoric applied to history == Vico's humanism (his returning to a pre-modern form of reasoning), his interest in classical rhetoric and philology, and his response to Descartes contribute to the philosophical foundations for the second Scienza Nuova. Through an elaborate Latin etymology, Vico establishes not only the distinguishing features of first humans, but also how early civilization developed out of a sensus communis or common (not collective) sense. Beginning with the first form of authority intuited by the giganti or early humans and transposed in their first "mute" or "sign" language, Vico concludes that “first, or vulgar, wisdom was poetic in nature.” This observation is not an aesthetic one, but rather points to the capacity inherent in all men to imagine meaning via comparison and to reach a communal "conscience" or "prejudice" about their surroundings. The metaphors that define the poetic age gradually yield to the first civic discourse, finally leading to a time characterized by "full-fledged reason" (ragione tutta spiegata), in which reason and right are exposed to the point that they vanish into their own superficial appearance. At this point, speech returns to its primitive condition, and with it men. Hence the "recurring" (ricorso) of life to "barbarism" (barbarie). It is by way of warning his age and those stemming from it of the danger of seeking truth in clear and distinct ideas blinding us to the real depths of life, that Vico calls our attention back to a classical art of moderating the course of human things, lest the liberty enjoyed in the "Republic" be supplanted by the anarchic tyranny of the senses. Crucial to Vico's work remains a subtle criticism of all attempts to impose universality upon particularity, as if ex nihilo. Instead, Vico attempts to always let "the true" emerge from "the certain" through innumerable stories and anecdotes drawn mostly from the history of Greece and Rome and from the Bible. Here, reason does not attempt to overcome the poetic dimension of life and speech, but to moderate its impulses so as to safeguard civil life. While the transfer from divine to heroic to human ages is, for Vico, marked by shifts in the tropological nature of language, the inventional aspect of the poetic principle remains constant. When referring to “poets”, Vico intends to evoke the original Greek sense of “creators”. In the Scienza Nuova, then, the verum factum principle first put forth in De Italorum Sapientia remains central. As such, the notion of topics as the loci or places of invention (put forth by Aristotle and developed throughout classical rhetoric) serves as the foundation for "the true", and thus, as the underlying principle of sensus communis and civic discourse. The development of laws that shape the social and political character of each age is informed as much by master tropes as by those topics deemed acceptable in each era. Thus, for the rudimentary civilization of the divine age, sensory topics are employed to develop laws applicable on an individual basis. These laws expand as metonymy and synecdoche enable notions of sovereign rule in the heroic age; accordingly, acceptable topics expand to include notions of class and division. In the final, human age, the reflection that enables popular democracy requires appeals to any and all topics to achieve a common, rational law that is universally applicable. The development of civilization in Vico's storia ideale eterna, then, is rooted in the first canon of rhetoric, as invention via loci shapes both the creation of and discourse about civil life. == Reception and later influence == Vico's major work was poorly received during his own life but has since inspired a cadre of famous thinkers and artists, including Karl Marx and Montesquieu. Later his work was received more favourably as in the case of Lord Monboddo to whom he was compared in a modern treatise. Isaiah Berlin has devoted attention to Vico as a critic of the Enlightenment and a significant humanist and culture theorist. Scienza Nuova was included by Martin Seymour-Smith in his book The 100 Most Influential Books Ever Written. The historical cycle provides the structure for James Joyce's book, Finnegans Wake. The intertextual relationship between Scienza Nuova and Finnegans Wake was brought to light by Samuel Beckett in his essay "Dante... Bruno. Vico.. Joyce” published in Our Exagmination Round His Factification for Incamination of Work in Progress (1929), where Beckett argued that Vico's conception of language also had significant influence in Joyce's work. Vico's notion of the lingua mentale commune (mental dictionary) in relation to universale fantastico reverberates in Joyce's novel, which ends in the middle of a sentence, reasserting Vico's principle of cyclical history. Language, knowledge and society are in a dialectical relationship, which means that any study or comparison of societies must consider the specific contexts of the societies. This has clearly influenced anthropology and sociology. == See also == Recapitulation theory De nostri temporis studiorum ratione Antipositivism Historicism Sociology of knowledge == References == == Further reading == Costelloe, Timothy. "Giambattista Vico". Retrieved 2010-09-30. Kreis, Steven. "Giambattista Vico, The New Science (1725)". Retrieved 2009-08-03. == External links == English translation from 1948 by Thomas Goddard Bergin and Max Harold Fisch is available here [1].
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Human science (or human sciences in the plural) studies the philosophical, biological, social, justice, and cultural aspects of human life. Human science aims to expand the understanding of the human world through a broad interdisciplinary approach. It encompasses a wide range of fields - including history, philosophy, sociology, psychology, justice studies, evolutionary biology, biochemistry, neurosciences, folkloristics, and anthropology. It is the study and interpretation of the experiences, activities, constructs, and artifacts associated with human beings. The study of human sciences attempts to expand and enlighten the human being's knowledge of its existence, its interrelationship with other species and systems, and the development of artifacts to perpetuate the human expression and thought. It is the study of human phenomena. The study of the human experience is historical and current in nature. It requires the evaluation and interpretation of the historic human experience and the analysis of current human activity to gain an understanding of human phenomena and to project the outlines of human evolution. Human science is an objective, informed critique of human existence and how it relates to reality.Underlying human science is the relationship between various humanistic modes of inquiry within fields such as history, sociology, folkloristics, anthropology, and economics and advances in such things as genetics, evolutionary biology, and the social sciences for the purpose of understanding our lives in a rapidly changing world. Its use of an empirical methodology that encompasses psychological experience in contrasts with the purely positivistic approach typical of the natural sciences which exceeds all methods not based solely on sensory observations. Modern approaches in the human sciences integrate an understanding of human structure, function on and adaptation with a broader exploration of what it means to be human. The term is also used to distinguish not only the content of a field of study from that of the natural science, but also its methodology. == Meaning of 'science' == Ambiguity and confusion regarding the usage of the terms 'science', 'empirical science', and 'scientific method' have complicated the usage of the term 'human science' with respect to human activities. The term 'science' is derived from the Latin scientia, meaning 'knowledge'. 'Science' may be appropriately used to refer to any branch of knowledge or study dealing with a body of facts or truths systematically arranged to show the operation of general laws. However, according to positivists, the only authentic knowledge is scientific knowledge, which comes from the positive affirmation of theories through strict scientific methods the application of knowledge, or mathematics. As a result of the positivist influence, the term science is frequently employed as a synonym for empirical science. Empirical science is knowledge based on the scientific method, a systematic approach to verification of knowledge first developed for dealing with natural physical phenomena and emphasizing the importance of experience based on sensory observation. However, even with regard to the natural sciences, significant differences exist among scientists and philosophers of science with regard to what constitutes valid scientific method—for example, evolutionary biology, geology and astronomy, studying events that cannot be repeated, can use the method of historical narratives. More recently, usage of the term has been extended to the study of human social phenomena. Thus, natural and social sciences are commonly classified as science, whereas the study of classics, languages, literature, music, philosophy, history, religion, and the visual and performing arts are referred to as the humanities. Ambiguity with respect to the meaning of the term science is aggravated by the widespread use of the term formal science with reference to any one of several sciences that is predominantly concerned with abstract form that cannot be validated by physical experience through the senses, such as logic, mathematics, and the theoretical branches of computer science, information theory, and statistics. == History == The phrase 'human science' in English was used during the 17th-century scientific revolution, for example by Theophilus Gale, to draw a distinction between supernatural knowledge (divine science) and study by humans (human science). John Locke also uses 'human science' to mean knowledge produced by people, but without the distinction. By the 20th century, this latter meaning was used at the same time as 'sciences that make human beings the topic of research'. === Early development === The term "moral science" was used by David Hume (1711–1776) in his Enquiry concerning the Principles of Morals to refer to the systematic study of human nature and relationships. Hume wished to establish a "science of human nature" based upon empirical phenomena, and excluding all that does not arise from observation. Rejecting teleological, theological and metaphysical explanations, Hume sought to develop an essentially descriptive methodology; phenomena were to be precisely characterized. He emphasized the necessity of carefully explicating the cognitive content of ideas and vocabulary, relating these to their empirical roots and real-world significance. A variety of early thinkers in the humanistic sciences took up Hume's direction. Adam Smith, for example, conceived of economics as a moral science in the Humean sense. === Later development === Partly in reaction to the establishment of positivist philosophy and the latter's Comtean intrusions into traditionally humanistic areas such as sociology, non-positivistic researchers in the humanistic sciences began to carefully but emphatically distinguish the methodological approach appropriate to these areas of study, for which the unique and distinguishing characteristics of phenomena are in the forefront (e.g., for the biographer), from that appropriate to the natural sciences, for which the ability to link phenomena into generalized groups is foremost. In this sense, Johann Gustav Droysen contrasted the humanistic science's need to comprehend the phenomena under consideration with natural science's need to explain phenomena, while Windelband coined the terms idiographic for a descriptive study of the individual nature of phenomena, and nomothetic for sciences that aim to defthe generalizing laws. Wilhelm Dilthey brought nineteenth-century attempts to formulate a methodology appropriate to the humanistic sciences together with Hume's term "moral science", which he translated as Geisteswissenschaft - a term with no exact English equivalent. Dilthey attempted to articulate the entire range of the moral sciences in a comprehensive and systematic way.: Chap. I Meanwhile, his conception of “Geisteswissenschaften” encompasses also the abovementioned study of classics, languages, literature, music, philosophy, history, religion, and the visual and performing arts. He characterized the scientific nature of a study as depending upon:: Chapter XI The conviction that perception gives access to reality The self-evident nature of logical reasoning The principle of sufficient reason But the specific nature of the Geisteswissenschaften is based on the "inner" experience (Erleben), the "comprehension" (Verstehen) of the meaning of expressions and "understanding" in terms of the relations of the part and the whole – in contrast to the Naturwissenschaften, the "explanation" of phenomena by hypothetical laws in the "natural sciences".: p. 86 Edmund Husserl, a student of Franz Brentano, articulated his phenomenological philosophy in a way that could be thought as a bthesis of Dilthey's attempt. Dilthey appreciated Husserl's Logische Untersuchungen (1900/1901, the first draft of Husserl's Phenomenology) as an “ep"epoch-making"istemological foundation of fors conception of Geisteswissenschaften.: p. 14 In recent years, 'human science' has been used to refer to "a philosophy and approach to science that seeks to understand human experience in deeply subjective, personal, historical, contextual, cross-cultural, political, and spiritual terms. Human science is the science of qualities rather than of quantities and closes the subject-object split in science. In particular, it addresses the ways in which self-reflection, art, music, poetry, drama, language and imagery reveal the human condition. By being interpretive, reflective, and appreciative, human science re-opens the conversation among science, art, and philosophy." == Objective vs. subjective experiences == Since Auguste Comte, the positivistic social sciences have sought to imitate the approach of the natural sciences by emphasizing the importance of objective external observations and searching for universal laws whose operation is predicated on external initial conditions that do not take into account differences in subjective human perception and attitude. Critics argue that subjective human experience and intention plays such a central role in determining human social behavior that an objective approach to the social sciences is too confining. Rejecting the positivist influence, they argue that the scientific method can rightly be applied to subjective, as well as objective, experience. The term subjective is used in this context to refer to inner psychological experience rather than outer sensory experience. It is not used in the sense of being prejudiced by personal motives or beliefs. == Human science in universities == Since 1878, the University of Cambridge has been home to the Moral Sciences Club, with strong ties to analytic philosophy. The Human Science degree is relatively young. It has been a degree subject at Oxford since 1969. At University College London, it was proposed in 1973 by Professor J. Z. Young and implemented two years later. His aim was to train general science graduates who would be scientifically literate, numerate and easily able to communicate across a wide range of disciplines, replacing the traditional classical training for higher-level government and management careers. Central topics include the evolution of humans, their behavior, molecular and population genetics, population growth and aging, ethnic and cultural diversity ,and human interaction with the environment, including conservation, disease ,and nutrition. The study of both biological and social disciplines, integrated within a framework of human diversity and sustainability, should enable the human scientist to develop professional competencies suited to address such multidimensional human problems. In the United Kingdom, Human Science is offered at the degree level at several institutions which include: University of Oxford University College London (as Human Sciences and as Human Sciences and Evolution) King's College London (as Anatomy, Developmental & Human Biology) University of Exeter Durham University (as Health and Human Sciences) Cardiff University (as Human and Social Sciences) In other countries: Osaka University Waseda University Tokiwa University Senshu University Aoyama Gakuin University (As College of Community Studies) Kobe University Kanagawa University Bunkyo University Sophia University Ghent University (in the narrow sense, as Moral sciences, "an integrated empirical and philosophical study of values, norms and world views") == See also == History of the Human Sciences (journal) Social science Humanism Humanities == References == == Bibliography == Flew, A. (1986). David Hume: Philosopher of Moral Science, Basil Blackwell, Oxford Hume, David, An Enquiry Concerning the Principles of Morals == External links == Institute for Comparative Research in Human and Social Sciences (ICR) -Japan Human Science Lab -London Human Science(s) across Global Academies Marxism philosophy
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Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the Moon (cosmochemistry), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics). Chemistry has existed under various names since ancient times. It has evolved, and now chemistry encompasses various areas of specialisation, or subdisciplines, that continue to increase in number and interrelate to create further interdisciplinary fields of study. The applications of various fields of chemistry are used frequently for economic purposes in the chemical industry. == Etymology == The word chemistry comes from a modification during the Renaissance of the word alchemy, which referred to an earlier set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism, and medicine. Alchemy is often associated with the quest to turn lead or other base metals into gold, though alchemists were also interested in many of the questions of modern chemistry. The modern word alchemy in turn is derived from the Arabic word al-kīmīā (الكیمیاء). This may have Egyptian origins since al-kīmīā is derived from the Ancient Greek χημία, which is in turn derived from the word Kemet, which is the ancient name of Egypt in the Egyptian language. Alternately, al-kīmīā may derive from χημεία 'cast together'. == Modern principles == The current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, atoms, molecules, substances, metals, crystals and other aggregates of matter. Matter can be studied in solid, liquid, gas and plasma states, in isolation or in combination. The interactions, reactions and transformations that are studied in chemistry are usually the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together. Such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware. However glassware is not central to chemistry, and a great deal of experimental (as well as applied/industrial) chemistry is done without it. A chemical reaction is a transformation of some substances into one or more different substances. The basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which usually involves atoms as subjects. The number of atoms on the left and the right in the equation for a chemical transformation is equal. (When the number of atoms on either side is unequal, the transformation is referred to as a nuclear reaction or radioactive decay.) The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws. Energy and entropy considerations are invariably important in almost all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions. They can be analyzed using the tools of chemical analysis, e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; some of them are: === Matter === In chemistry, matter is defined as anything that has rest mass and volume (it takes up space) and is made up of particles. The particles that make up matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a pure chemical substance or a mixture of substances. ==== Atom ==== The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons. The nucleus is dense; the mass of a nucleon is approximately 1,836 times that of an electron, yet the radius of an atom is about 10,000 times that of its nucleus. The atom is also the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state(s), coordination number, and preferred types of bonds to form (e.g., metallic, ionic, covalent). ==== Element ==== A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z. The mass number is the sum of the number of protons and neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same atomic number, they may not necessarily have the same mass number; atoms of an element which have different mass numbers are known as isotopes. For example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbon, but atoms of carbon may have mass numbers of 12 or 13. The standard presentation of the chemical elements is in the periodic table, which orders elements by atomic number. The periodic table is arranged in groups, or columns, and periods, or rows. The periodic table is useful in identifying periodic trends. ==== Compound ==== A compound is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements. The standard nomenclature of compounds is set by the International Union of Pure and Applied Chemistry (IUPAC). Organic compounds are named according to the organic nomenclature system. The names for inorganic compounds are created according to the inorganic nomenclature system. When a compound has more than one component, then they are divided into two classes, the electropositive and the electronegative components. In addition the Chemical Abstracts Service (CAS) has devised a method to index chemical substances. In this scheme each chemical substance is identifiable by a number known as its CAS registry number. ==== Molecule ==== A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well for substances that are composed of molecules, which is not true of many substances (see below). Molecules are typically a set of atoms bound together by covalent bonds, such that the structure is electrically neutral and all valence electrons are paired with other electrons either in bonds or in lone pairs. Thus, molecules exist as electrically neutral units, unlike ions. When this rule is broken, giving the "molecule" a charge, the result is sometimes named a molecular ion or a polyatomic ion. However, the discrete and separate nature of the molecular concept usually requires that molecular ions be present only in well-separated form, such as a directed beam in a vacuum in a mass spectrometer. Charged polyatomic collections residing in solids (for example, common sulfate or nitrate ions) are generally not considered "molecules" in chemistry. Some molecules contain one or more unpaired electrons, creating radicals. Most radicals are comparatively reactive, but some, such as nitric oxide (NO) can be stable. The "inert" or noble gas elements (helium, neon, argon, krypton, xenon and radon) are composed of lone atoms as their smallest discrete unit, but the other isolated chemical elements consist of either molecules or networks of atoms bonded to each other in some way. Identifiable molecules compose familiar substances such as water, air, and many organic compounds like alcohol, sugar, gasoline, and the various pharmaceuticals. However, not all substances or chemical compounds consist of discrete molecules, and indeed most of the solid substances that make up the solid crust, mantle, and core of the Earth are chemical compounds without molecules. These other types of substances, such as ionic compounds and network solids, are organized in such a way as to lack the existence of identifiable molecules per se. Instead, these substances are discussed in terms of formula units or unit cells as the smallest repeating structure within the substance. Examples of such substances are mineral salts (such as table salt), solids like carbon and diamond, metals, and familiar silica and silicate minerals such as quartz and granite. One of the main characteristics of a molecule is its geometry often called its structure. While the structure of diatomic, triatomic or tetra-atomic molecules may be trivial, (linear, angular pyramidal etc.) the structure of polyatomic molecules, that are constituted of more than six atoms (of several elements) can be crucial for its chemical nature. ==== Substance and mixture ==== A chemical substance is a kind of matter with a definite composition and set of properties. A collection of substances is called a mixture. Examples of mixtures are air and alloys. ==== Mole and amount of substance ==== The mole is a unit of measurement that denotes an amount of substance (also called chemical amount). One mole is defined to contain exactly 6.02214076×1023 particles (atoms, molecules, ions, or electrons), where the number of particles per mole is known as the Avogadro constant. Molar concentration is the amount of a particular substance per volume of solution, and is commonly reported in mol/dm3. === Phase === In addition to the specific chemical properties that distinguish different chemical classifications, chemicals can exist in several phases. For the most part, the chemical classifications are independent of these bulk phase classifications; however, some more exotic phases are incompatible with certain chemical properties. A phase is a set of states of a chemical system that have similar bulk structural properties, over a range of conditions, such as pressure or temperature. Physical properties, such as density and refractive index tend to fall within values characteristic of the phase. The phase of matter is defined by the phase transition, which is when energy put into or taken out of the system goes into rearranging the structure of the system, instead of changing the bulk conditions. Sometimes the distinction between phases can be continuous instead of having a discrete boundary; in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a set of conditions. The most familiar examples of phases are solids, liquids, and gases. Many substances exhibit multiple solid phases. For example, there are three phases of solid iron (alpha, gamma, and delta) that vary based on temperature and pressure. A principal difference between solid phases is the crystal structure, or arrangement, of the atoms. Another phase commonly encountered in the study of chemistry is the aqueous phase, which is the state of substances dissolved in aqueous solution (that is, in water). Less familiar phases include plasmas, Bose–Einstein condensates and fermionic condensates and the paramagnetic and ferromagnetic phases of magnetic materials. While most familiar phases deal with three-dimensional systems, it is also possible to define analogs in two-dimensional systems, which has received attention for its relevance to systems in biology. === Bonding === Atoms sticking together in molecules or crystals are said to be bonded with one another. A chemical bond may be visualized as the multipole balance between the positive charges in the nuclei and the negative charges oscillating about them. More than simple attraction and repulsion, the energies and distributions characterize the availability of an electron to bond to another atom. The chemical bond can be a covalent bond, an ionic bond, a hydrogen bond or just because of Van der Waals force. Each of these kinds of bonds is ascribed to some potential. These potentials create the interactions which hold atoms together in molecules or crystals. In many simple compounds, valence bond theory, the Valence Shell Electron Pair Repulsion model (VSEPR), and the concept of oxidation number can be used to explain molecular structure and composition. An ionic bond is formed when a metal loses one or more of its electrons, becoming a positively charged cation, and the electrons are then gained by the non-metal atom, becoming a negatively charged anion. The two oppositely charged ions attract one another, and the ionic bond is the electrostatic force of attraction between them. For example, sodium (Na), a metal, loses one electron to become an Na+ cation while chlorine (Cl), a non-metal, gains this electron to become Cl−. The ions are held together due to electrostatic attraction, and that compound sodium chloride (NaCl), or common table salt, is formed. In a covalent bond, one or more pairs of valence electrons are shared by two atoms: the resulting electrically neutral group of bonded atoms is termed a molecule. Atoms will share valence electrons in such a way as to create a noble gas electron configuration (eight electrons in their outermost shell) for each atom. Atoms that tend to combine in such a way that they each have eight electrons in their valence shell are said to follow the octet rule. However, some elements like hydrogen and lithium need only two electrons in their outermost shell to attain this stable configuration; these atoms are said to follow the duet rule, and in this way they are reaching the electron configuration of the noble gas helium, which has two electrons in its outer shell. Similarly, theories from classical physics can be used to predict many ionic structures. With more complicated compounds, such as metal complexes, valence bond theory is less applicable and alternative approaches, such as the molecular orbital theory, are generally used. === Energy === In the context of chemistry, energy is an attribute of a substance as a consequence of its atomic, molecular or aggregate structure. Since a chemical transformation is accompanied by a change in one or more of these kinds of structures, it is invariably accompanied by an increase or decrease of energy of the substances involved. Some energy is transferred between the surroundings and the reactants of the reaction in the form of heat or light; thus the products of a reaction may have more or less energy than the reactants. A reaction is said to be exergonic if the final state is lower on the energy scale than the initial state; in the case of endergonic reactions the situation is the reverse. A reaction is said to be exothermic if the reaction releases heat to the surroundings; in the case of endothermic reactions, the reaction absorbs heat from the surroundings. Chemical reactions are invariably not possible unless the reactants surmount an energy barrier known as the activation energy. The speed of a chemical reaction (at given temperature T) is related to the activation energy E, by the Boltzmann's population factor e − E / k T {\displaystyle e^{-E/kT}} – that is the probability of a molecule to have energy greater than or equal to E at the given temperature T. This exponential dependence of a reaction rate on temperature is known as the Arrhenius equation. The activation energy necessary for a chemical reaction to occur can be in the form of heat, light, electricity or mechanical force in the form of ultrasound. A related concept free energy, which also incorporates entropy considerations, is a very useful means for predicting the feasibility of a reaction and determining the state of equilibrium of a chemical reaction, in chemical thermodynamics. A reaction is feasible only if the total change in the Gibbs free energy is negative, Δ G ≤ 0 {\displaystyle \Delta G\leq 0\,} ; if it is equal to zero the chemical reaction is said to be at equilibrium. There exist only limited possible states of energy for electrons, atoms and molecules. These are determined by the rules of quantum mechanics, which require quantization of energy of a bound system. The atoms/molecules in a higher energy state are said to be excited. The molecules/atoms of substance in an excited energy state are often much more reactive; that is, more amenable to chemical reactions. The phase of a substance is invariably determined by its energy and the energy of its surroundings. When the intermolecular forces of a substance are such that the energy of the surroundings is not sufficient to overcome them, it occurs in a more ordered phase like liquid or solid as is the case with water (H2O); a liquid at room temperature because its molecules are bound by hydrogen bonds. Whereas hydrogen sulfide (H2S) is a gas at room temperature and standard pressure, as its molecules are bound by weaker dipole–dipole interactions. The transfer of energy from one chemical substance to another depends on the size of energy quanta emitted from one substance. However, heat energy is often transferred more easily from almost any substance to another because the phonons responsible for vibrational and rotational energy levels in a substance have much less energy than photons invoked for the electronic energy transfer. Thus, because vibrational and rotational energy levels are more closely spaced than electronic energy levels, heat is more easily transferred between substances relative to light or other forms of electronic energy. For example, ultraviolet electromagnetic radiation is not transferred with as much efficacy from one substance to another as thermal or electrical energy. The existence of characteristic energy levels for different chemical substances is useful for their identification by the analysis of spectral lines. Different kinds of spectra are often used in chemical spectroscopy, e.g. IR, microwave, NMR, ESR, etc. Spectroscopy is also used to identify the composition of remote objects – like stars and distant galaxies – by analyzing their radiation spectra. The term chemical energy is often used to indicate the potential of a chemical substance to undergo a transformation through a chemical reaction or to transform other chemical substances. === Reaction === When a chemical substance is transformed as a result of its interaction with another substance or with energy, a chemical reaction is said to have occurred. A chemical reaction is therefore a concept related to the "reaction" of a substance when it comes in close contact with another, whether as a mixture or a solution; exposure to some form of energy, or both. It results in some energy exchange between the constituents of the reaction as well as with the system environment, which may be designed vessels—often laboratory glassware. Chemical reactions can result in the formation or dissociation of molecules, that is, molecules breaking apart to form two or more molecules or rearrangement of atoms within or across molecules. Chemical reactions usually involve the making or breaking of chemical bonds. Oxidation, reduction, dissociation, acid–base neutralization and molecular rearrangement are some examples of common chemical reactions. A chemical reaction can be symbolically depicted through a chemical equation. While in a non-nuclear chemical reaction the number and kind of atoms on both sides of the equation are equal, for a nuclear reaction this holds true only for the nuclear particles viz. protons and neutrons. The sequence of steps in which the reorganization of chemical bonds may be taking place in the course of a chemical reaction is called its mechanism. A chemical reaction can be envisioned to take place in a number of steps, each of which may have a different speed. Many reaction intermediates with variable stability can thus be envisaged during the course of a reaction. Reaction mechanisms are proposed to explain the kinetics and the relative product mix of a reaction. Many physical chemists specialize in exploring and proposing the mechanisms of various chemical reactions. Several empirical rules, like the Woodward–Hoffmann rules often come in handy while proposing a mechanism for a chemical reaction. According to the IUPAC gold book, a chemical reaction is "a process that results in the interconversion of chemical species." Accordingly, a chemical reaction may be an elementary reaction or a stepwise reaction. An additional caveat is made, in that this definition includes cases where the interconversion of conformers is experimentally observable. Such detectable chemical reactions normally involve sets of molecular entities as indicated by this definition, but it is often conceptually convenient to use the term also for changes involving single molecular entities (i.e. 'microscopic chemical events'). === Ions and salts === An ion is a charged species, an atom or a molecule, that has lost or gained one or more electrons. When an atom loses an electron and thus has more protons than electrons, the atom is a positively charged ion or cation. When an atom gains an electron and thus has more electrons than protons, the atom is a negatively charged ion or anion. Cations and anions can form a crystalline lattice of neutral salts, such as the Na+ and Cl− ions forming sodium chloride, or NaCl. Examples of polyatomic ions that do not split up during acid–base reactions are hydroxide (OH−) and phosphate (PO43−). Plasma is composed of gaseous matter that has been completely ionized, usually through high temperature. === Acidity and basicity === A substance can often be classified as an acid or a base. There are several different theories which explain acid–base behavior. The simplest is Arrhenius theory, which states that an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water. According to Brønsted–Lowry acid–base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction; by extension, a base is the substance which receives that hydrogen ion. A third common theory is Lewis acid–base theory, which is based on the formation of new chemical bonds. Lewis theory explains that an acid is a substance which is capable of accepting a pair of electrons from another substance during the process of bond formation, while a base is a substance which can provide a pair of electrons to form a new bond. There are several other ways in which a substance may be classified as an acid or a base, as is evident in the history of this concept. Acid strength is commonly measured by two methods. One measurement, based on the Arrhenius definition of acidity, is pH, which is a measurement of the hydronium ion concentration in a solution, as expressed on a negative logarithmic scale. Thus, solutions that have a low pH have a high hydronium ion concentration and can be said to be more acidic. The other measurement, based on the Brønsted–Lowry definition, is the acid dissociation constant (Ka), which measures the relative ability of a substance to act as an acid under the Brønsted–Lowry definition of an acid. That is, substances with a higher Ka are more likely to donate hydrogen ions in chemical reactions than those with lower Ka values. === Redox === Redox (reduction-oxidation) reactions include all chemical reactions in which atoms have their oxidation state changed by either gaining electrons (reduction) or losing electrons (oxidation). Substances that have the ability to oxidize other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers. An oxidant removes electrons from another substance. Similarly, substances that have the ability to reduce other substances are said to be reductive and are known as reducing agents, reductants, or reducers. A reductant transfers electrons to another substance and is thus oxidized itself. And because it "donates" electrons it is also called an electron donor. Oxidation and reduction properly refer to a change in oxidation number—the actual transfer of electrons may never occur. Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number. === Equilibrium === Although the concept of equilibrium is widely used across sciences, in the context of chemistry, it arises whenever a number of different states of the chemical composition are possible, as for example, in a mixture of several chemical compounds that can react with one another, or when a substance can be present in more than one kind of phase. A system of chemical substances at equilibrium, even though having an unchanging composition, is most often not static; molecules of the substances continue to react with one another thus giving rise to a dynamic equilibrium. Thus the concept describes the state in which the parameters such as chemical composition remain unchanged over time. === Chemical laws === Chemical reactions are governed by certain laws, which have become fundamental concepts in chemistry. Some of them are: == History == The history of chemistry spans a period from the ancient past to the present. Since several millennia BC, civilizations were using technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making glass, and making alloys like bronze. Chemistry was preceded by its protoscience, alchemy, which operated a non-scientific approach to understanding the constituents of matter and their interactions. Despite being unsuccessful in explaining the nature of matter and its transformations, alchemists set the stage for modern chemistry by performing experiments and recording the results. Robert Boyle, although skeptical of elements and convinced of alchemy, played a key part in elevating the "sacred art" as an independent, fundamental and philosophical discipline in his work The Sceptical Chymist (1661). While both alchemy and chemistry are concerned with matter and its transformations, the crucial difference was given by the scientific method that chemists employed in their work. Chemistry, as a body of knowledge distinct from alchemy, became an established science with the work of Antoine Lavoisier, who developed a law of conservation of mass that demanded careful measurement and quantitative observations of chemical phenomena. The history of chemistry afterwards is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs. === Definition === The definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term "chymistry", in the view of noted scientist Robert Boyle in 1661, meant the subject of the material principles of mixed bodies. In 1663, the chemist Christopher Glaser described "chymistry" as a scientific art, by which one learns to dissolve bodies, and draw from them the different substances on their composition, and how to unite them again, and exalt them to a higher perfection. The 1730 definition of the word "chemistry", as used by Georg Ernst Stahl, meant the art of resolving mixed, compound, or aggregate bodies into their principles; and of composing such bodies from those principles. In 1837, Jean-Baptiste Dumas considered the word "chemistry" to refer to the science concerned with the laws and effects of molecular forces. This definition further evolved until, in 1947, it came to mean the science of substances: their structure, their properties, and the reactions that change them into other substances—a characterization accepted by Linus Pauling. More recently, in 1998, Professor Raymond Chang broadened the definition of "chemistry" to mean the study of matter and the changes it undergoes. === Background === Early civilizations, such as the Egyptians, Babylonians, and Indians, amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but did not develop a systematic theory. A basic chemical hypothesis first emerged in Classical Greece with the theory of four elements as propounded definitively by Aristotle stating that fire, air, earth and water were the fundamental elements from which everything is formed as a combination. Greek atomism dates back to 440 BC, arising in works by philosophers such as Democritus and Epicurus. In 50 BCE, the Roman philosopher Lucretius expanded upon the theory in his poem De rerum natura (On The Nature of Things). Unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments. An early form of the idea of conservation of mass is the notion that "Nothing comes from nothing" in Ancient Greek philosophy, which can be found in Empedocles (approx. 4th century BC): "For it is impossible for anything to come to be from what is not, and it cannot be brought about or heard of that what is should be utterly destroyed." and Epicurus (3rd century BC), who, describing the nature of the Universe, wrote that "the totality of things was always such as it is now, and always will be". In the Hellenistic world the art of alchemy first proliferated, mingling magic and occultism into the study of natural substances with the ultimate goal of transmuting elements into gold and discovering the elixir of eternal life. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. Alchemy continued to be developed and practised throughout the Arab world after the Muslim conquests, and from there, and from the Byzantine remnants, diffused into medieval and Renaissance Europe through Latin translations. The Arabic works attributed to Jabir ibn Hayyan introduced a systematic classification of chemical substances, and provided instructions for deriving an inorganic compound (sal ammoniac or ammonium chloride) from organic substances (such as plants, blood, and hair) by chemical means. Some Arabic Jabirian works (e.g., the "Book of Mercy", and the "Book of Seventy") were later translated into Latin under the Latinized name "Geber", and in 13th-century Europe an anonymous writer, usually referred to as pseudo-Geber, started to produce alchemical and metallurgical writings under this name. Later influential Muslim philosophers, such as Abū al-Rayhān al-Bīrūnī and Avicenna disputed the theories of alchemy, particularly the theory of the transmutation of metals. Improvements of the refining of ores and their extractions to smelt metals was widely used source of information for early chemists in the 16th century, among them Georg Agricola (1494–1555), who published his major work De re metallica in 1556. His work, describing highly developed and complex processes of mining metal ores and metal extraction, were the pinnacle of metallurgy during that time. His approach removed all mysticism associated with the subject, creating the practical base upon which others could and would build. The work describes the many kinds of furnaces used to smelt ore, and stimulated interest in minerals and their composition. Agricola has been described as the "father of metallurgy" and the founder of geology as a scientific discipline. Under the influence of the new empirical methods propounded by Sir Francis Bacon and others, a group of chemists at Oxford, Robert Boyle, Robert Hooke and John Mayow began to reshape the old alchemical traditions into a scientific discipline. Boyle in particular questioned some commonly held chemical theories and argued for chemical practitioners to be more "philosophical" and less commercially focused in The Sceptical Chemyst. He formulated Boyle's law, rejected the classical "four elements" and proposed a mechanistic alternative of atoms and chemical reactions that could be subject to rigorous experiment. In the following decades, many important discoveries were made, such as the nature of 'air' which was discovered to be composed of many different gases. The Scottish chemist Joseph Black and the Flemish Jan Baptist van Helmont discovered carbon dioxide, or what Black called 'fixed air' in 1754; Henry Cavendish discovered hydrogen and elucidated its properties and Joseph Priestley and, independently, Carl Wilhelm Scheele isolated pure oxygen. The theory of phlogiston (a substance at the root of all combustion) was propounded by the German Georg Ernst Stahl in the early 18th century and was only overturned by the end of the century by the French chemist Antoine Lavoisier, the chemical analogue of Newton in physics. Lavoisier did more than any other to establish the new science on proper theoretical footing, by elucidating the principle of conservation of mass and developing a new system of chemical nomenclature used to this day. English scientist John Dalton proposed the modern theory of atoms; that all substances are composed of indivisible 'atoms' of matter and that different atoms have varying atomic weights. The development of the electrochemical theory of chemical combinations occurred in the early 19th century as the result of the work of two scientists in particular, Jöns Jacob Berzelius and Humphry Davy, made possible by the prior invention of the voltaic pile by Alessandro Volta. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current. British William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. J.A.R. Newlands devised an early table of elements, which was then developed into the modern periodic table of elements in the 1860s by Dmitri Mendeleev and independently by several other scientists including Julius Lothar Meyer. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhler's synthesis of urea. Other crucial 19th century advances were; an understanding of valence bonding (Edward Frankland in 1852) and the application of thermodynamics to chemistry (J. W. Gibbs and Svante Arrhenius in the 1870s). At the turn of the twentieth century the theoretical underpinnings of chemistry were finally understood due to a series of remarkable discoveries that succeeded in probing and discovering the very nature of the internal structure of atoms. In 1897, J.J. Thomson of the University of Cambridge discovered the electron and soon after the French scientist Becquerel as well as the couple Pierre and Marie Curie investigated the phenomenon of radioactivity. In a series of pioneering scattering experiments Ernest Rutherford at the University of Manchester discovered the internal structure of the atom and the existence of the proton, classified and explained the different types of radioactivity and successfully transmuted the first element by bombarding nitrogen with alpha particles. His work on atomic structure was improved on by his students, the Danish physicist Niels Bohr, the Englishman Henry Moseley and the German Otto Hahn, who went on to father the emerging nuclear chemistry and discovered nuclear fission. The electronic theory of chemical bonds and molecular orbitals was developed by the American scientists Linus Pauling and Gilbert N. Lewis. The year 2011 was declared by the United Nations as the International Year of Chemistry. It was an initiative of the International Union of Pure and Applied Chemistry, and of the United Nations Educational, Scientific, and Cultural Organization and involves chemical societies, academics, and institutions worldwide and relied on individual initiatives to organize local and regional activities. == Practice == In the practice of chemistry, pure chemistry is the study of the fundamental principles of chemistry, while applied chemistry applies that knowledge to develop technology and solve real-world problems. === Subdisciplines === Chemistry is typically divided into several major sub-disciplines. There are also several main cross-disciplinary and more specialized fields of chemistry. Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure. Analytical chemistry incorporates standardized experimental methods in chemistry. These methods may be used in all subdisciplines of chemistry, excluding purely theoretical chemistry. Biochemistry is the study of the chemicals, chemical reactions and interactions that take place at a molecular level in living organisms. Biochemistry is highly interdisciplinary, covering medicinal chemistry, neurochemistry, molecular biology, forensics, plant science and genetics. Inorganic chemistry is the study of the properties and reactions of inorganic compounds, such as metals and minerals. The distinction between organic and inorganic disciplines is not absolute and there is much overlap, most importantly in the sub-discipline of organometallic chemistry. Materials chemistry is the preparation, characterization, and understanding of solid state components or devices with a useful current or future function. The field is a new breadth of study in graduate programs, and it integrates elements from all classical areas of chemistry like organic chemistry, inorganic chemistry, and crystallography with a focus on fundamental issues that are unique to materials. Primary systems of study include the chemistry of condensed phases (solids, liquids, polymers) and interfaces between different phases. Neurochemistry is the study of neurochemicals; including transmitters, peptides, proteins, lipids, sugars, and nucleic acids; their interactions, and the roles they play in forming, maintaining, and modifying the nervous system. Nuclear chemistry is the study of how subatomic particles come together and make nuclei. Modern transmutation is a large component of nuclear chemistry, and the table of nuclides is an important result and tool for this field. In addition to medical applications, nuclear chemistry encompasses nuclear engineering which explores the topic of using nuclear power sources for generating energy. Organic chemistry is the study of the structure, properties, composition, mechanisms, and reactions of organic compounds. An organic compound is defined as any compound based on a carbon skeleton. Organic compounds can be classified, organized and understood in reactions by their functional groups, unit atoms or molecules that show characteristic chemical properties in a compound. Physical chemistry is the study of the physical and fundamental basis of chemical systems and processes. In particular, the energetics and dynamics of such systems and processes are of interest to physical chemists. Important areas of study include chemical thermodynamics, chemical kinetics, electrochemistry, statistical mechanics, spectroscopy, and more recently, astrochemistry. Physical chemistry has large overlap with molecular physics. Physical chemistry involves the use of infinitesimal calculus in deriving equations. It is usually associated with quantum chemistry and theoretical chemistry. Physical chemistry is a distinct discipline from chemical physics, but again, there is very strong overlap. Theoretical chemistry is the study of chemistry via fundamental theoretical reasoning (usually within mathematics or physics). In particular the application of quantum mechanics to chemistry is called quantum chemistry. Since the end of the Second World War, the development of computers has allowed a systematic development of computational chemistry, which is the art of developing and applying computer programs for solving chemical problems. Theoretical chemistry has large overlap with (theoretical and experimental) condensed matter physics and molecular physics. Other subdivisions include electrochemistry, femtochemistry, flavor chemistry, flow chemistry, immunohistochemistry, hydrogenation chemistry, mathematical chemistry, molecular mechanics, natural product chemistry, organometallic chemistry, petrochemistry, photochemistry, physical organic chemistry, polymer chemistry, radiochemistry, sonochemistry, supramolecular chemistry, synthetic chemistry, and many others. === Interdisciplinary === Interdisciplinary fields include agrochemistry, astrochemistry (and cosmochemistry), atmospheric chemistry, chemical engineering, chemical biology, chemo-informatics, environmental chemistry, geochemistry, green chemistry, immunochemistry, marine chemistry, materials science, mechanochemistry, medicinal chemistry, molecular biology, nanotechnology, oenology, pharmacology, phytochemistry, solid-state chemistry, surface science, thermochemistry, and many others. === Industry === The chemical industry represents an important economic activity worldwide. The global top 50 chemical producers in 2013 had sales of US$980.5 billion with a profit margin of 10.3%. === Professional societies === == See also == == References == == Bibliography == == Further reading == Popular reading Atkins, P. W. Galileo's Finger (Oxford University Press) ISBN 0-19-860941-8 Atkins, P. W. Atkins' Molecules (Cambridge University Press) ISBN 0-521-82397-8 Kean, Sam. The Disappearing Spoon – and Other True Tales from the Periodic Table (Black Swan) London, England, 2010 ISBN 978-0-552-77750-6 Levi, Primo The Periodic Table (Penguin Books) [1975] translated from the Italian by Raymond Rosenthal (1984) ISBN 978-0-14-139944-7 Stwertka, A. A Guide to the Elements (Oxford University Press) ISBN 0-19-515027-9 "Dictionary of the History of Ideas". Archived from the original on 10 March 2008. "Chemistry" . Encyclopædia Britannica. Vol. 6 (11th ed.). 1911. pp. 33–76. Introductory undergraduate textbooks Atkins, P.W., Overton, T., Rourke, J., Weller, M. and Armstrong, F. Shriver and Atkins Inorganic Chemistry (4th ed.) 2006 (Oxford University Press) ISBN 0-19-926463-5 Chang, Raymond. Chemistry 6th ed. Boston, Massachusetts: James M. Smith, 1998. ISBN 0-07-115221-0 Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. ISBN 978-0-19-850346-0. Voet and Voet. Biochemistry (Wiley) ISBN 0-471-58651-X Advanced undergraduate-level or graduate textbooks Atkins, P. W. Physical Chemistry (Oxford University Press) ISBN 0-19-879285-9 Atkins, P. W. et al. Molecular Quantum Mechanics (Oxford University Press) McWeeny, R. Coulson's Valence (Oxford Science Publications) ISBN 0-19-855144-4 Pauling, L. The Nature of the chemical bond (Cornell University Press) ISBN 0-8014-0333-2 Pauling, L., and Wilson, E. B. Introduction to Quantum Mechanics with Applications to Chemistry (Dover Publications) ISBN 0-486-64871-0 Smart and Moore. Solid State Chemistry: An Introduction (Chapman and Hall) ISBN 0-412-40040-5 Stephenson, G. Mathematical Methods for Science Students (Longman) ISBN 0-582-44416-0 == External links == General Chemistry principles, patterns and applications.
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Research is creative and systematic work undertaken to increase the stock of knowledge. It involves the collection, organization, and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness to controlling sources of bias and error. These activities are characterized by accounting and controlling for biases. A research project may be an expansion of past work in the field. To test the validity of instruments, procedures, or experiments, research may replicate elements of prior projects or the project as a whole. The primary purposes of basic research (as opposed to applied research) are documentation, discovery, interpretation, and the research and development (R&D) of methods and systems for the advancement of human knowledge. Approaches to research depend on epistemologies, which vary considerably both within and between humanities and sciences. There are several forms of research: scientific, humanities, artistic, economic, social, business, marketing, practitioner research, life, technological, etc. The scientific study of research practices is known as meta-research. A researcher is a person who conducts research, especially in order to discover new information or to reach a new understanding. In order to be a social researcher or a social scientist, one should have enormous knowledge of subjects related to social science that they are specialized in. Similarly, in order to be a natural science researcher, the person should have knowledge of fields related to natural science (physics, chemistry, biology, astronomy, zoology and so on). Professional associations provide one pathway to mature in the research profession. == Etymology == The word research is derived from the Middle French "recherche", which means "to go about seeking", the term itself being derived from the Old French term "recerchier," a compound word from "re-" + "cerchier", or "sercher", meaning 'search'. The earliest recorded use of the term was in 1577. == Definitions == Research has been defined in a number of different ways, and while there are similarities, there does not appear to be a single, all-encompassing definition that is embraced by all who engage in it. Research, in its simplest terms, is searching for knowledge and searching for truth. In a formal sense, it is a systematic study of a problem attacked by a deliberately chosen strategy, which starts with choosing an approach to preparing a blueprint (design) and acting upon it in terms of designing research hypotheses, choosing methods and techniques, selecting or developing data collection tools, processing the data, interpretation, and ending with presenting solution(s) of the problem. Another definition of research is given by John W. Creswell, who states that "research is a process of steps used to collect and analyze information to increase our understanding of a topic or issue". It consists of three steps: pose a question, collect data to answer the question, and present an answer to the question. The Merriam-Webster Online Dictionary defines research more generally to also include studying already existing knowledge: "studious inquiry or examination; especially: investigation or experimentation aimed at the discovery and interpretation of facts, revision of accepted theories or laws in the light of new facts, or practical application of such new or revised theories or laws". == Forms of research == === Original research === Original research, also called primary research, is research that is not exclusively based on a summary, review, or synthesis of earlier publications on the subject of research. This material is of a primary-source character. The purpose of the original research is to produce new knowledge rather than present the existing knowledge in a new form (e.g., summarized or classified). Original research can take various forms, depending on the discipline it pertains to. In experimental work, it typically involves direct or indirect observation of the researched subject(s), e.g., in the laboratory or in the field, documents the methodology, results, and conclusions of an experiment or set of experiments, or offers a novel interpretation of previous results. In analytical work, there are typically some new (for example) mathematical results produced or a new way of approaching an existing problem. In some subjects which do not typically carry out experimentation or analysis of this kind, the originality is in the particular way existing understanding is changed or re-interpreted based on the outcome of the work of the researcher. The degree of originality of the research is among the major criteria for articles to be published in academic journals and usually established by means of peer review. Graduate students are commonly required to perform original research as part of a dissertation. === Scientific research === Scientific research is a systematic way of gathering data and harnessing curiosity. This research provides scientific information and theories for the explanation of the nature and the properties of the world. It makes practical applications possible. Scientific research may be funded by public authorities, charitable organizations, and private organizations. Scientific research can be subdivided by discipline. Generally, research is understood to follow a certain structural process. Though the order may vary depending on the subject matter and researcher, the following steps are usually part of most formal research, both basic and applied: Observations and formation of the topic: Consists of the subject area of one's interest and following that subject area to conduct subject-related research. The subject area should not be randomly chosen since it requires reading a vast amount of literature on the topic to determine the gap in the literature the researcher intends to narrow. A keen interest in the chosen subject area is advisable. The research will have to be justified by linking its importance to already existing knowledge about the topic. Hypothesis: A testable prediction which designates the relationship between two or more variables. Conceptual definition: Description of a concept by relating it to other concepts. Operational definition: Details in regards to defining the variables and how they will be measured/assessed in the study. Gathering of data: Consists of identifying a population and selecting samples, gathering information from or about these samples by using specific research instruments. The instruments used for data collection must be valid and reliable. Analysis of data: Involves breaking down the individual pieces of data to draw conclusions about it. Data Interpretation: This can be represented through tables, figures, and pictures, and then described in words. Test, revising of hypothesis Conclusion, reiteration if necessary A common misconception is that a hypothesis will be proven (see, rather, null hypothesis). Generally, a hypothesis is used to make predictions that can be tested by observing the outcome of an experiment. If the outcome is inconsistent with the hypothesis, then the hypothesis is rejected (see falsifiability). However, if the outcome is consistent with the hypothesis, the experiment is said to support the hypothesis. This careful language is used because researchers recognize that alternative hypotheses may also be consistent with the observations. In this sense, a hypothesis can never be proven, but rather only supported by surviving rounds of scientific testing and, eventually, becoming widely thought of as true. A useful hypothesis allows prediction and within the accuracy of observation of the time, the prediction will be verified. As the accuracy of observation improves with time, the hypothesis may no longer provide an accurate prediction. In this case, a new hypothesis will arise to challenge the old, and to the extent that the new hypothesis makes more accurate predictions than the old, the new will supplant it. Researchers can also use a null hypothesis, which states no relationship or difference between the independent or dependent variables. === Research in the humanities === Research in the humanities involves different methods such as for example hermeneutics and semiotics. Humanities scholars usually do not search for the ultimate correct answer to a question, but instead, explore the issues and details that surround it. Context is always important, and context can be social, historical, political, cultural, or ethnic. An example of research in the humanities is historical research, which is embodied in historical method. Historians use primary sources and other evidence to systematically investigate a topic, and then to write histories in the form of accounts of the past. Other studies aim to merely examine the occurrence of behaviours in societies and communities, without particularly looking for reasons or motivations to explain these. These studies may be qualitative or quantitative, and can use a variety of approaches, such as queer theory or feminist theory. === Artistic research === Artistic research, also seen as 'practice-based research', can take form when creative works are considered both the research and the object of research itself. It is the debatable body of thought which offers an alternative to purely scientific methods in research in its search for knowledge and truth. The controversial trend of artistic teaching becoming more academics-oriented is leading to artistic research being accepted as the primary mode of enquiry in art as in the case of other disciplines. One of the characteristics of artistic research is that it must accept subjectivity as opposed to the classical scientific methods. As such, it is similar to the social sciences in using qualitative research and intersubjectivity as tools to apply measurement and critical analysis. Artistic research has been defined by the School of Dance and Circus (Dans och Cirkushögskolan, DOCH), Stockholm in the following manner – "Artistic research is to investigate and test with the purpose of gaining knowledge within and for our artistic disciplines. It is based on artistic practices, methods, and criticality. Through presented documentation, the insights gained shall be placed in a context." Artistic research aims to enhance knowledge and understanding with presentation of the arts. A simpler understanding by Julian Klein defines artistic research as any kind of research employing the artistic mode of perception. For a survey of the central problematics of today's artistic research, see Giaco Schiesser. According to artist Hakan Topal, in artistic research, "perhaps more so than other disciplines, intuition is utilized as a method to identify a wide range of new and unexpected productive modalities". Most writers, whether of fiction or non-fiction books, also have to do research to support their creative work. This may be factual, historical, or background research. Background research could include, for example, geographical or procedural research. The Society for Artistic Research (SAR) publishes the triannual Journal for Artistic Research (JAR), an international, online, open access, and peer-reviewed journal for the identification, publication, and dissemination of artistic research and its methodologies, from all arts disciplines and it runs the Research Catalogue (RC), a searchable, documentary database of artistic research, to which anyone can contribute. Patricia Leavy addresses eight arts-based research (ABR) genres: narrative inquiry, fiction-based research, poetry, music, dance, theatre, film, and visual art. In 2016, the European League of Institutes of the Arts launched The Florence Principles' on the Doctorate in the Arts. The Florence Principles relating to the Salzburg Principles and the Salzburg Recommendations of the European University Association name seven points of attention to specify the Doctorate / PhD in the Arts compared to a scientific doctorate / PhD. The Florence Principles have been endorsed and are supported also by AEC, CILECT, CUMULUS and SAR. === Historical research === The historical method comprises the techniques and guidelines by which historians use historical sources and other evidence to research and then to write history. There are various history guidelines that are commonly used by historians in their work, under the headings of external criticism, internal criticism, and synthesis. This includes lower criticism and sensual criticism. Though items may vary depending on the subject matter and researcher, the following concepts are part of most formal historical research: Identification of origin date Evidence of localization Recognition of authorship Analysis of data Identification of integrity Attribution of credibility === Documentary research === == Steps in conducting research == Research is often conducted using the hourglass model structure of research. The hourglass model starts with a broad spectrum for research, focusing in on the required information through the method of the project (like the neck of the hourglass), then expands the research in the form of discussion and results. The major steps in conducting research are: Identification of research problem Literature review Specifying the purpose of research Determining specific research questions Specification of a conceptual framework, sometimes including a set of hypotheses Choice of a methodology (for data collection) Data collection Verifying data Analyzing and interpreting the data Reporting and evaluating research Communicating the research findings and, possibly, recommendations The steps generally represent the overall process; however, they should be viewed as an ever-changing iterative process rather than a fixed set of steps. Most research begins with a general statement of the problem, or rather, the purpose for engaging in the study. The literature review identifies flaws or holes in previous research which provides justification for the study. Often, a literature review is conducted in a given subject area before a research question is identified. A gap in the current literature, as identified by a researcher, then engenders a research question. The research question may be parallel to the hypothesis. The hypothesis is the supposition to be tested. The researcher(s) collects data to test the hypothesis. The researcher(s) then analyzes and interprets the data via a variety of statistical methods, engaging in what is known as empirical research. The results of the data analysis in rejecting or failing to reject the null hypothesis are then reported and evaluated. At the end, the researcher may discuss avenues for further research. However, some researchers advocate for the reverse approach: starting with articulating findings and discussion of them, moving "up" to identification of a research problem that emerges in the findings and literature review. The reverse approach is justified by the transactional nature of the research endeavor where research inquiry, research questions, research method, relevant research literature, and so on are not fully known until the findings have fully emerged and been interpreted. Rudolph Rummel says, "... no researcher should accept any one or two tests as definitive. It is only when a range of tests are consistent over many kinds of data, researchers, and methods can one have confidence in the results." Plato in Meno talks about an inherent difficulty, if not a paradox, of doing research that can be paraphrased in the following way, "If you know what you're searching for, why do you search for it?! [i.e., you have already found it] If you don't know what you're searching for, what are you searching for?!" == Research methods == The goal of the research process is to produce new knowledge or deepen understanding of a topic or issue. This process takes three main forms (although, as previously discussed, the boundaries between them may be obscure): Exploratory research, which helps to identify and define a problem or question. Constructive research, which tests theories and proposes solutions to a problem or question. Empirical research, which tests the feasibility of a solution using empirical evidence. There are two major types of empirical research design: qualitative research and quantitative research. Researchers choose qualitative or quantitative methods according to the nature of the research topic they want to investigate and the research questions they aim to answer: Qualitative research Qualitative research refers to much more subjective non-quantitative, use different methods of collecting data, analyzing data, interpreting data for meanings, definitions, characteristics, symbols metaphors of things. Qualitative research further classified into the following types: Ethnography: This research mainly focus on culture of group of people which includes share attributes, language, practices, structure, value, norms and material things, evaluate human lifestyle. Ethno: people, Grapho: to write, this disciple may include ethnic groups, ethno genesis, composition, resettlement and social welfare characteristics. Phenomenology: It is very powerful strategy for demonstrating methodology to health professions education as well as best suited for exploring challenging problems in health professions educations. In addition, PMP researcher Mandy Sha argued that a project management approach is necessary to control the scope, schedule, and cost related to qualitative research design, participant recruitment, data collection, reporting, as well as stakeholder engagement. Quantitative research Quantitative research involves systematic empirical investigation of quantitative properties and phenomena and their relationships, by asking a narrow question and collecting numerical data to analyze it utilizing statistical methods. The quantitative research designs are experimental, correlational, and survey (or descriptive). Statistics derived from quantitative research can be used to establish the existence of associative or causal relationships between variables. Quantitative research is linked with the philosophical and theoretical stance of positivism. The quantitative data collection methods rely on random sampling and structured data collection instruments that fit diverse experiences into predetermined response categories. These methods produce results that can be summarized, compared, and generalized to larger populations if the data are collected using proper sampling and data collection strategies. Quantitative research is concerned with testing hypotheses derived from theory or being able to estimate the size of a phenomenon of interest. If the research question is about people, participants may be randomly assigned to different treatments (this is the only way that a quantitative study can be considered a true experiment). If this is not feasible, the researcher may collect data on participant and situational characteristics to statistically control for their influence on the dependent, or outcome, variable. If the intent is to generalize from the research participants to a larger population, the researcher will employ probability sampling to select participants. In either qualitative or quantitative research, the researcher(s) may collect primary or secondary data. Primary data is data collected specifically for the research, such as through interviews or questionnaires. Secondary data is data that already exists, such as census data, which can be re-used for the research. It is good ethical research practice to use secondary data wherever possible. Mixed-method research, i.e. research that includes qualitative and quantitative elements, using both primary and secondary data, is becoming more common. This method has benefits that using one method alone cannot offer. For example, a researcher may choose to conduct a qualitative study and follow it up with a quantitative study to gain additional insights. Big data has brought big impacts on research methods so that now many researchers do not put much effort into data collection; furthermore, methods to analyze easily available huge amounts of data have also been developed. Non-empirical research Non-empirical (theoretical) research is an approach that involves the development of theory as opposed to using observation and experimentation. As such, non-empirical research seeks solutions to problems using existing knowledge as its source. This, however, does not mean that new ideas and innovations cannot be found within the pool of existing and established knowledge. Non-empirical research is not an absolute alternative to empirical research because they may be used together to strengthen a research approach. Neither one is less effective than the other since they have their particular purpose in science. Typically empirical research produces observations that need to be explained; then theoretical research tries to explain them, and in so doing generates empirically testable hypotheses; these hypotheses are then tested empirically, giving more observations that may need further explanation; and so on. See Scientific method. A simple example of a non-empirical task is the prototyping of a new drug using a differentiated application of existing knowledge; another is the development of a business process in the form of a flow chart and texts where all the ingredients are from established knowledge. Much of cosmological research is theoretical in nature. Mathematics research does not rely on externally available data; rather, it seeks to prove theorems about mathematical objects. == Research ethics == == Problems in research == === Metascience === Metascience is the study of research through the use of research methods. Also known as "research on research", it aims to reduce waste and increase the quality of research in all fields. Meta-research concerns itself with the detection of bias, methodological flaws, and other errors and inefficiencies. Among the finding of meta-research is a low rates of reproducibility across a large number of fields. === Replication crisis === === Academic bias === === Funding bias === === Publication bias === === Non-western methods === In many disciplines, Western methods of conducting research are predominant. Researchers are overwhelmingly taught Western methods of data collection and study. The increasing participation of indigenous peoples as researchers has brought increased attention to the scientific lacuna in culturally sensitive methods of data collection. Western methods of data collection may not be the most accurate or relevant for research on non-Western societies. For example, "Hua Oranga" was created as a criterion for psychological evaluation in Māori populations, and is based on dimensions of mental health important to the Māori people – "taha wairua (the spiritual dimension), taha hinengaro (the mental dimension), taha tinana (the physical dimension), and taha whanau (the family dimension)". Even though Western dominance seems to be prominent in research, some scholars, such as Simon Marginson, argue for "the need [for] a plural university world". Marginson argues that the East Asian Confucian model could take over the Western model. This could be due to changes in funding for research both in the East and the West. Focused on emphasizing educational achievement, East Asian cultures, mainly in China and South Korea, have encouraged the increase of funding for research expansion. In contrast, in the Western academic world, notably in the United Kingdom as well as in some state governments in the United States, funding cuts for university research have occurred, which some say may lead to the future decline of Western dominance in research. === Language === Research is often biased in the languages that are preferred (linguicism) and the geographic locations where research occurs. Periphery scholars face the challenges of exclusion and linguicism in research and academic publication. As the great majority of mainstream academic journals are written in English, multilingual periphery scholars often must translate their work to be accepted to elite Western-dominated journals. Multilingual scholars' influences from their native communicative styles can be assumed to be incompetence instead of difference. Patterns of geographic bias also show a relationship with linguicism: countries whose official languages are French or Arabic are far less likely to be the focus of single-country studies than countries with different official languages. Within Africa, English-speaking countries are more represented than other countries. === Generalizability === Generalization is the process of more broadly applying the valid results of one study. Studies with a narrow scope can result in a lack of generalizability, meaning that the results may not be applicable to other populations or regions. In comparative politics, this can result from using a single-country study, rather than a study design that uses data from multiple countries. Despite the issue of generalizability, single-country studies have risen in prevalence since the late 2000s. For comparative politics, Western countries are over-represented in single-country studies, with heavy emphasis on Western Europe, Canada, Australia, and New Zealand. Since 2000, Latin American countries have become more popular in single-country studies. In contrast, countries in Oceania and the Caribbean are the focus of very few studies. === Publication peer review === Peer review is a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are employed to maintain standards of quality, improve performance, and provide credibility. In academia, scholarly peer review is often used to determine an academic paper's suitability for publication. Usually, the peer review process involves experts in the same field who are consulted by editors to give a review of the scholarly works produced by a colleague of theirs from an unbiased and impartial point of view, and this is usually done free of charge. The tradition of peer reviews being done for free has however brought many pitfalls which are also indicative of why most peer reviewers decline many invitations to review. It was observed that publications from periphery countries rarely rise to the same elite status as those of North America and Europe. === Open research === The open research, open science and open access movements assume that all information generally deemed useful should be free and belongs to a "public domain", that of "humanity". This idea gained prevalence as a result of Western colonial history and ignores alternative conceptions of knowledge circulation. For instance, most indigenous communities consider that access to certain information proper to the group should be determined by relationships. There is alleged to be a double standard in the Western knowledge system. On the one hand, "digital right management" used to restrict access to personal information on social networking platforms is celebrated as a protection of privacy, while simultaneously when similar functions are used by cultural groups (i.e. indigenous communities) this is denounced as "access control" and reprehended as censorship. == Professionalisation == In several national and private academic systems, the professionalisation of research has resulted in formal job titles. === In Russia === In present-day Russia, and some other countries of the former Soviet Union, the term researcher (Russian: Научный сотрудник, nauchny sotrudnik) has been used both as a generic term for a person who has been carrying out scientific research, and as a job position within the frameworks of the Academy of Sciences, universities, and in other research-oriented establishments. The following ranks are known: Junior Researcher (Junior Research Associate) Researcher (Research Associate) Senior Researcher (Senior Research Associate) Leading Researcher (Leading Research Associate) Chief Researcher (Chief Research Associate) == Publishing == Academic publishing is a system that is necessary for academic scholars to peer review the work and make it available for a wider audience. The system varies widely by field and is also always changing, if often slowly. Most academic work is published in journal article or book form. There is also a large body of research that exists in either a thesis or dissertation form. These forms of research can be found in databases explicitly for theses and dissertations. In publishing, STM publishing is an abbreviation for academic publications in science, technology, and medicine. Most established academic fields have their own scientific journals and other outlets for publication, though many academic journals are somewhat interdisciplinary, and publish work from several distinct fields or subfields. The kinds of publications that are accepted as contributions of knowledge or research vary greatly between fields, from the print to the electronic format. A study suggests that researchers should not give great consideration to findings that are not replicated frequently. It has also been suggested that all published studies should be subjected to some measure for assessing the validity or reliability of its procedures to prevent the publication of unproven findings. Business models are different in the electronic environment. Since about the early 1990s, licensing of electronic resources, particularly journals, has been very common. Presently, a major trend, particularly with respect to scholarly journals, is open access. There are two main forms of open access: open access publishing, in which the articles or the whole journal is freely available from the time of publication, and self-archiving, where the author makes a copy of their own work freely available on the web. == Research statistics and funding == Most funding for scientific research comes from three major sources: corporate research and development departments; private foundations; and government research councils such as the National Institutes of Health in the US and the Medical Research Council in the UK. These are managed primarily through universities and in some cases through military contractors. Many senior researchers (such as group leaders) spend a significant amount of their time applying for grants for research funds. These grants are necessary not only for researchers to carry out their research but also as a source of merit. The Social Psychology Network provides a comprehensive list of U.S. Government and private foundation funding sources. The total number of researchers (full-time equivalents) per million inhabitants for individual countries is shown in the following table. Research expenditure by type of research as a share of GDP for individual countries is shown in the following table. == See also == == Notes == == References == == Sources == Creswell, John W. (2008). Educational Research: Planning, conducting, and evaluating quantitative and qualitative research (3rd ed.). Upper Saddle River, NJ: Pearson. ISBN 0-13-613550-1. Kara, Helen (2012). Research and Evaluation for Busy Practitioners: A Time-Saving Guide. Bristol: The Policy Press. ISBN 978-1-44730-115-8. == Further reading == Groh, Arnold (2018). Research Methods in Indigenous Contexts. New York: Springer. ISBN 978-3-319-72774-5. Cohen, N.; Arieli, T. (2011). "Field research in conflict environments: Methodological challenges and snowball sampling". Journal of Peace Research. 48 (4): 423–436. doi:10.1177/0022343311405698. S2CID 145328311. Soeters, Joseph; Shields, Patricia and Rietjens, Sebastiaan. 2014. Handbook of Research Methods in Military Studies New York: Routledge. Talja, Sanna and Pamela J. Mckenzie (2007). Editor's Introduction: Special Issue on Discursive Approaches to Information Seeking in Context, The University of Chicago Press. == External links == The dictionary definition of research at Wiktionary Quotations related to Research at Wikiquote Media related to Research at Wikimedia Commons
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The Web of Science (WoS; previously known as Web of Knowledge) is a paid-access platform that provides (typically via the internet) access to multiple databases that provide reference and citation data from academic journals, conference proceedings, and other documents in various academic disciplines. Until 1997, it was originally produced by the Institute for Scientific Information. It is currently owned by Clarivate. Web of Science currently contains 79 million records in the core collection and 171 million records on the platform. == History == A citation index is built on the fact that citations in science serve as linkages between similar research items, and lead to matching or related scientific literature, such as journal articles, conference proceedings, abstracts, etc. In addition, literature that shows the greatest impact in a particular field, or more than one discipline, can be located through a citation index. For example, a paper's influence can be determined by linking to all the papers that have cited it. In this way, current trends, patterns, and emerging fields of research can be assessed. Eugene Garfield, the "father of citation indexing of academic literature", who launched the Science Citation Index, which in turn led to the Web of Science, wrote: Citations are the formal, explicit linkages between papers that have particular points in common. A citation index is built around these linkages. It lists publications that have been cited and identifies the sources of the citations. Anyone conducting a literature search can find from one to dozens of additional papers on a subject just by knowing one that has been cited. And every paper that is found provides a list of new citations with which to continue the search. The simplicity of citation indexing is one of its main strengths. === Search answer === Web of Science "is a unifying research tool which enables the user to acquire, analyze, and disseminate database information in a timely manner". This is accomplished because of the creation of a common vocabulary, called ontology, for varied search terms and varied data. Moreover, search terms generate related information across categories. Acceptable content for Web of Science is determined by an evaluation and selection process based on the following criteria: impact, influence, timeliness, peer review, and geographic representation. Web of Science employs various search and analysis capabilities. First, citation indexing is employed, which is enhanced by the capability to search for results across disciplines. The influence, impact, history, and methodology of an idea can be followed from its first instance, notice, or referral to the present day. This technology points to a deficiency with the keyword-only method of searching. Second, subtle trends and patterns relevant to the literature or research of interest, become apparent. Broad trends indicate significant topics of the day, as well as the history relevant to both the work at hand, and particular areas of study. Third, trends can be graphically represented. == Coverage == Expanding the coverage of Web of Science, in November 2009 Thomson Reuters introduced Century of Social Sciences. This service contains files which trace social science research back to the beginning of the 20th century, and Web of Science now has indexing coverage from the year 1900 to the present. As of February 2017, the multidisciplinary coverage of the Web of Science encompasses: over a billion cited references, 90 million records, covering over 12 thousand high impact journals, and 8.2 million records across 160 thousand conference proceedings, with 15 thousand proceedings added each year. The selection is made on the basis of impact evaluations and comprise academic journals, spanning multiple academic disciplines. The coverage includes: the sciences, social sciences, the arts, and humanities, and goes across disciplines. However, Web of Science does not index all journals. There is a significant and positive correlation between the impact factor and CiteScore. However, an analysis by Elsevier, who created the journal evaluation metric CiteScore, has identified 216 journals from 70 publishers to be in the top 10 percent of the most-cited journals in their subject category based on the CiteScore while they did not have an impact factor. It appears that the impact factor does not provide comprehensive and unbiased coverage of high-quality journals. Similar results can be observed by comparing the impact factor with the SCImago Journal Rank. Furthermore, as of September 2014, the total file count of the Web of Science was over 90 million records, which included over 800 million cited references, covering 5.3 thousand social science publications in 55 disciplines. Titles of foreign-language publications are translated into English and so cannot be found by searches in the original language. In 2018, the Web of Science started embedding partial information about the open access status of works, using Unpaywall data. While marketed as a global point of reference, Scopus and WoS have been characterised as «structurally biased against research produced in non-Western countries, non-English language research, and research from the arts, humanities, and social sciences». After the 2022 Russian invasion of Ukraine, on March 11, 2022, Clarivate – which owns Web of Science – announced that it would cease all commercial activity in Russia and immediately close an office there. == Citation databases == The Web of Science Core Collection consists of six online indexing databases: Science Citation Index Expanded (SCIE), previously entitled Science Citation Index, covers more than 9,200 journals across 178 scientific disciplines. Coverage is from 1900 to present day, with over 53 million records Social Sciences Citation Index (SSCI) covers more than 3,400 journals in the social sciences. Coverage is from 1900 to present, with over 9.3 million records Arts & Humanities Citation Index (AHCI) covers more than 1,800 journals in the arts and humanities. Coverage is from 1975 to present, with over 4.9 million records Emerging Sources Citation Index (ESCI) covers more than 7,800 journals in all disciplines. Coverage is from 2005 to present, with over 3 million records Book Citation Index (BCI) covers more than 116,000 editorially selected books. Coverage is from 2005 to present, with over 53.2 million records Conference Proceedings Citation Index (CPCI) covers more than 205,000 conference proceedings. Coverage is from 1990 to present, with over 70.1 million records === Regional databases === Since 2008, the Web of Science hosts a number of regional citation indices: Chinese Science Citation Database, produced in partnership with the Chinese Academy of Sciences, was the first indexing database in a language other than English SciELO Citation Index, established in 2013, covering Brazil, Spain, Portugal, the Caribbean and South Africa, and an additional 12 countries of Latin America Korea Citation Index in 2014, with updates from the National Research Foundation of Korea Russian Science Citation Index in 2015 Arabic Regional Citation Index in 2020 === Contents === The seven citation indices listed above contain references which have been cited by other articles. One may use them to undertake cited reference search, that is, locating articles that cite an earlier, or current publication. One may search citation databases by topic, by author, by source title, and by location. Two chemistry databases, Index Chemicus and Current Chemical Reactions allow for the creation of structure drawings, thus enabling users to locate chemical compounds and reactions. === Abstracting and indexing === The following types of literature are indexed: scholarly books, peer reviewed journals, original research articles, reviews, editorials, chronologies, abstracts, as well as other items. Disciplines included in this index are agriculture, biological sciences, engineering, medical and life sciences, physical and chemical sciences, anthropology, law, library sciences, architecture, dance, music, film, and theater. Seven citation databases encompasses coverage of the above disciplines. === Other databases and products === Among other WoS databases are BIOSIS and The Zoological Record, an electronic index of zoological literature that also serves as the unofficial register of scientific names in zoology. Clarivate owns and markets numerous other products that provide data and analytics, workflow tools, and professional services to researchers, universities, research institutions, and other organizations, such as: InCites Journal Citation Reports Essential Science Indicators ScholarOne Converis == Limitations in the use of citation analysis == As with other scientific approaches, scientometrics and bibliometrics have their own limitations. In 2010, a criticism was voiced pointing toward certain deficiencies of the journal impact factor calculation process, based on Thomson Reuters Web of Science, such as: journal citation distributions usually are highly skewed towards established journals; journal impact factor properties are field-specific and can be easily manipulated by editors, or even by changing the editorial policies; this makes the entire process essentially non-transparent. Regarding the more objective journal metrics, there is a growing view that for greater accuracy it must be supplemented with article-level metrics and peer-review. Studies of methodological quality and reliability have found that "reliability of published research works in several fields may be decreasing with increasing journal rank". Thomson Reuters replied to criticism in general terms by stating that "no one metric can fully capture the complex contributions scholars make to their disciplines, and many forms of scholarly achievement should be considered." == Journal Citation Reports == == See also == == References == == External links == Official website == Further reading == Cantú-Ortiz, Francisco Javier, ed. (2017-10-25). "2. Web of Science: The First Citation Index for Data Analytics and Scientometrics". Research Analytics: Boosting University Productivity and Competitiveness through Scientometrics (1st ed.). New York City: CRC Press. pp. 15–30. doi:10.1201/9781315155890. ISBN 978-1-315-15589-0.
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https://en.wikipedia.org/wiki/Web_of_Science
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Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into two or three major branches: the natural sciences (e.g., physics, chemistry, and biology), which study the physical world; and the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies. Applied sciences are disciplines that use scientific knowledge for practical purposes, such as engineering and medicine. While sometimes referred to as the formal sciences, the study of logic, mathematics, and theoretical computer science (which study formal systems governed by axioms and rules) are typically regarded as separate because they rely on deductive reasoning instead of the scientific method or empirical evidence as their main methodology. The history of science spans the majority of the historical record, with the earliest identifiable predecessors to modern science dating to the Bronze Age in Egypt and Mesopotamia (c. 3000–1200 BCE). Their contributions to mathematics, astronomy, and medicine entered and shaped the Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes, while further advancements, including the introduction of the Hindu–Arabic numeral system, were made during the Golden Age of India.: 12 Scientific research deteriorated in these regions after the fall of the Western Roman Empire during the Early Middle Ages (400–1000 CE), but in the Medieval renaissances (Carolingian Renaissance, Ottonian Renaissance and the Renaissance of the 12th century) scholarship flourished again. Some Greek manuscripts lost in Western Europe were preserved and expanded upon in the Middle East during the Islamic Golden Age, Later, Byzantine Greek scholars contributed to their transmission by bringing Greek manuscripts from the declining Byzantine Empire to Western Europe at the beginning of the Renaissance. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th centuries revived natural philosophy, which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and in the 19th century many of the institutional and professional features of science began to take shape, along with the changing of "natural philosophy" to "natural science". New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions, government agencies, and companies. The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritising the ethical and moral development of commercial products, armaments, health care, public infrastructure, and environmental protection. == Etymology == The word science has been used in Middle English since the 14th century in the sense of "the state of knowing". The word was borrowed from the Anglo-Norman language as the suffix -cience, which was borrowed from the Latin word scientia, meaning "knowledge, awareness, understanding", a noun derivative of sciens meaning "knowing", itself the present active participle of sciō, "to know". There are many hypotheses for science's ultimate word origin. According to Michiel de Vaan, Dutch linguist and Indo-Europeanist, sciō may have its origin in the Proto-Italic language as *skije- or *skijo- meaning "to know", which may originate from Proto-Indo-European language as *skh1-ie, *skh1-io, meaning "to incise". The Lexikon der indogermanischen Verben proposed sciō is a back-formation of nescīre, meaning "to not know, be unfamiliar with", which may derive from Proto-Indo-European *sekH- in Latin secāre, or *skh2-, from *sḱʰeh2(i)- meaning "to cut". In the past, science was a synonym for "knowledge" or "study", in keeping with its Latin origin. A person who conducted scientific research was called a "natural philosopher" or "man of science". In 1834, William Whewell introduced the term scientist in a review of Mary Somerville's book On the Connexion of the Physical Sciences, crediting it to "some ingenious gentleman" (possibly himself). == History == === Early history === Science has no single origin. Rather, scientific thinking emerged gradually over the course of tens of thousands of years, taking different forms around the world, and few details are known about the very earliest developments. Women likely played a central role in prehistoric science, as did religious rituals. Some scholars use the term "protoscience" to label activities in the past that resemble modern science in some but not all features; however, this label has also been criticised as denigrating, or too suggestive of presentism, thinking about those activities only in relation to modern categories. Direct evidence for scientific processes becomes clearer with the advent of writing systems in the Bronze Age civilisations of Ancient Egypt and Mesopotamia (c. 3000–1200 BCE), creating the earliest written records in the history of science.: 12–15 Although the words and concepts of "science" and "nature" were not part of the conceptual landscape at the time, the ancient Egyptians and Mesopotamians made contributions that would later find a place in Greek and medieval science: mathematics, astronomy, and medicine.: 12 From the 3rd millennium BCE, the ancient Egyptians developed a non-positional decimal numbering system, solved practical problems using geometry, and developed a calendar. Their healing therapies involved drug treatments and the supernatural, such as prayers, incantations, and rituals.: 9 The ancient Mesopotamians used knowledge about the properties of various natural chemicals for manufacturing pottery, faience, glass, soap, metals, lime plaster, and waterproofing. They studied animal physiology, anatomy, behaviour, and astrology for divinatory purposes. The Mesopotamians had an intense interest in medicine and the earliest medical prescriptions appeared in Sumerian during the Third Dynasty of Ur. They seem to have studied scientific subjects which had practical or religious applications and had little interest in satisfying curiosity. === Classical antiquity === In classical antiquity, there is no real ancient analogue of a modern scientist. Instead, well-educated, usually upper-class, and almost universally male individuals performed various investigations into nature whenever they could afford the time. Before the invention or discovery of the concept of phusis or nature by the pre-Socratic philosophers, the same words tend to be used to describe the natural "way" in which a plant grows, and the "way" in which, for example, one tribe worships a particular god. For this reason, it is claimed that these men were the first philosophers in the strict sense and the first to clearly distinguish "nature" and "convention". The early Greek philosophers of the Milesian school, which was founded by Thales of Miletus and later continued by his successors Anaximander and Anaximenes, were the first to attempt to explain natural phenomena without relying on the supernatural. The Pythagoreans developed a complex number philosophy: 467–468 and contributed significantly to the development of mathematical science.: 465 The theory of atoms was developed by the Greek philosopher Leucippus and his student Democritus. Later, Epicurus would develop a full natural cosmology based on atomism, and would adopt a "canon" (ruler, standard) which established physical criteria or standards of scientific truth. The Greek doctor Hippocrates established the tradition of systematic medical science and is known as "The Father of Medicine". A turning point in the history of early philosophical science was Socrates' example of applying philosophy to the study of human matters, including human nature, the nature of political communities, and human knowledge itself. The Socratic method as documented by Plato's dialogues is a dialectic method of hypothesis elimination: better hypotheses are found by steadily identifying and eliminating those that lead to contradictions. The Socratic method searches for general commonly-held truths that shape beliefs and scrutinises them for consistency. Socrates criticised the older type of study of physics as too purely speculative and lacking in self-criticism. In the 4th century BCE, Aristotle created a systematic programme of teleological philosophy. In the 3rd century BCE, Greek astronomer Aristarchus of Samos was the first to propose a heliocentric model of the universe, with the Sun at the centre and all the planets orbiting it. Aristarchus's model was widely rejected because it was believed to violate the laws of physics, while Ptolemy's Almagest, which contains a geocentric description of the Solar System, was accepted through the early Renaissance instead. The inventor and mathematician Archimedes of Syracuse made major contributions to the beginnings of calculus. Pliny the Elder was a Roman writer and polymath, who wrote the seminal encyclopaedia Natural History. Positional notation for representing numbers likely emerged between the 3rd and 5th centuries CE along Indian trade routes. This numeral system made efficient arithmetic operations more accessible and would eventually become standard for mathematics worldwide. === Middle Ages === Due to the collapse of the Western Roman Empire, the 5th century saw an intellectual decline, with knowledge of classical Greek conceptions of the world deteriorating in Western Europe.: 194 Latin encyclopaedists of the period such as Isidore of Seville preserved the majority of general ancient knowledge. In contrast, because the Byzantine Empire resisted attacks from invaders, they were able to preserve and improve prior learning.: 159 John Philoponus, a Byzantine scholar in the 6th century, started to question Aristotle's teaching of physics, introducing the theory of impetus.: 307, 311, 363, 402 His criticism served as an inspiration to medieval scholars and Galileo Galilei, who extensively cited his works ten centuries later.: 307–308 During late antiquity and the Early Middle Ages, natural phenomena were mainly examined via the Aristotelian approach. The approach includes Aristotle's four causes: material, formal, moving, and final cause. Many Greek classical texts were preserved by the Byzantine Empire and Arabic translations were made by Christians, mainly Nestorians and Miaphysites. Under the Abbasids, these Arabic translations were later improved and developed by Arabic scientists. By the 6th and 7th centuries, the neighbouring Sasanian Empire established the medical Academy of Gondishapur, which was considered by Greek, Syriac, and Persian physicians as the most important medical hub of the ancient world. Islamic study of Aristotelianism flourished in the House of Wisdom established in the Abbasid capital of Baghdad, Iraq and the flourished until the Mongol invasions in the 13th century. Ibn al-Haytham, better known as Alhazen, used controlled experiments in his optical study. Avicenna's compilation of The Canon of Medicine, a medical encyclopaedia, is considered to be one of the most important publications in medicine and was used until the 18th century. By the 11th century most of Europe had become Christian,: 204 and in 1088, the University of Bologna emerged as the first university in Europe. As such, demand for Latin translation of ancient and scientific texts grew,: 204 a major contributor to the Renaissance of the 12th century. Renaissance scholasticism in western Europe flourished, with experiments done by observing, describing, and classifying subjects in nature. In the 13th century, medical teachers and students at Bologna began opening human bodies, leading to the first anatomy textbook based on human dissection by Mondino de Luzzi. === Renaissance === New developments in optics played a role in the inception of the Renaissance, both by challenging long-held metaphysical ideas on perception, as well as by contributing to the improvement and development of technology such as the camera obscura and the telescope. At the start of the Renaissance, Roger Bacon, Vitello, and John Peckham each built up a scholastic ontology upon a causal chain beginning with sensation, perception, and finally apperception of the individual and universal forms of Aristotle.: Book I A model of vision later known as perspectivism was exploited and studied by the artists of the Renaissance. This theory uses only three of Aristotle's four causes: formal, material, and final. In the 16th century, Nicolaus Copernicus formulated a heliocentric model of the Solar System, stating that the planets revolve around the Sun, instead of the geocentric model where the planets and the Sun revolve around the Earth. This was based on a theorem that the orbital periods of the planets are longer as their orbs are farther from the centre of motion, which he found not to agree with Ptolemy's model. Johannes Kepler and others challenged the notion that the only function of the eye is perception, and shifted the main focus in optics from the eye to the propagation of light. Kepler is best known, however, for improving Copernicus' heliocentric model through the discovery of Kepler's laws of planetary motion. Kepler did not reject Aristotelian metaphysics and described his work as a search for the Harmony of the Spheres. Galileo had made significant contributions to astronomy, physics and engineering. However, he became persecuted after Pope Urban VIII sentenced him for writing about the heliocentric model. The printing press was widely used to publish scholarly arguments, including some that disagreed widely with contemporary ideas of nature. Francis Bacon and René Descartes published philosophical arguments in favour of a new type of non-Aristotelian science. Bacon emphasised the importance of experiment over contemplation, questioned the Aristotelian concepts of formal and final cause, promoted the idea that science should study the laws of nature and the improvement of all human life. Descartes emphasised individual thought and argued that mathematics rather than geometry should be used to study nature. === Age of Enlightenment === At the start of the Age of Enlightenment, Isaac Newton formed the foundation of classical mechanics by his Philosophiæ Naturalis Principia Mathematica, greatly influencing future physicists. Gottfried Wilhelm Leibniz incorporated terms from Aristotelian physics, now used in a new non-teleological way. This implied a shift in the view of objects: objects were now considered as having no innate goals. Leibniz assumed that different types of things all work according to the same general laws of nature, with no special formal or final causes. During this time the declared purpose and value of science became producing wealth and inventions that would improve human lives, in the materialistic sense of having more food, clothing, and other things. In Bacon's words, "the real and legitimate goal of sciences is the endowment of human life with new inventions and riches", and he discouraged scientists from pursuing intangible philosophical or spiritual ideas, which he believed contributed little to human happiness beyond "the fume of subtle, sublime or pleasing [speculation]". Science during the Enlightenment was dominated by scientific societies and academies, which had largely replaced universities as centres of scientific research and development. Societies and academies were the backbones of the maturation of the scientific profession. Another important development was the popularisation of science among an increasingly literate population. Enlightenment philosophers turned to a few of their scientific predecessors – Galileo, Kepler, Boyle, and Newton principally – as the guides to every physical and social field of the day. The 18th century saw significant advancements in the practice of medicine and physics; the development of biological taxonomy by Carl Linnaeus; a new understanding of magnetism and electricity; and the maturation of chemistry as a discipline. Ideas on human nature, society, and economics evolved during the Enlightenment. Hume and other Scottish Enlightenment thinkers developed A Treatise of Human Nature, which was expressed historically in works by authors including James Burnett, Adam Ferguson, John Millar and William Robertson, all of whom merged a scientific study of how humans behaved in ancient and primitive cultures with a strong awareness of the determining forces of modernity. Modern sociology largely originated from this movement. In 1776, Adam Smith published The Wealth of Nations, which is often considered the first work on modern economics. === 19th century === During the 19th century, many distinguishing characteristics of contemporary modern science began to take shape. These included the transformation of the life and physical sciences; the frequent use of precision instruments; the emergence of terms such as "biologist", "physicist", and "scientist"; an increased professionalisation of those studying nature; scientists gaining cultural authority over many dimensions of society; the industrialisation of numerous countries; the thriving of popular science writings; and the emergence of science journals. During the late 19th century, psychology emerged as a separate discipline from philosophy when Wilhelm Wundt founded the first laboratory for psychological research in 1879. During the mid-19th century Charles Darwin and Alfred Russel Wallace independently proposed the theory of evolution by natural selection in 1858, which explained how different plants and animals originated and evolved. Their theory was set out in detail in Darwin's book On the Origin of Species, published in 1859. Separately, Gregor Mendel presented his paper, "Experiments on Plant Hybridisation" in 1865, which outlined the principles of biological inheritance, serving as the basis for modern genetics. Early in the 19th century John Dalton suggested the modern atomic theory, based on Democritus's original idea of indivisible particles called atoms. The laws of conservation of energy, conservation of momentum and conservation of mass suggested a highly stable universe where there could be little loss of resources. However, with the advent of the steam engine and the Industrial Revolution there was an increased understanding that not all forms of energy have the same energy qualities, the ease of conversion to useful work or to another form of energy. This realisation led to the development of the laws of thermodynamics, in which the free energy of the universe is seen as constantly declining: the entropy of a closed universe increases over time. The electromagnetic theory was established in the 19th century by the works of Hans Christian Ørsted, André-Marie Ampère, Michael Faraday, James Clerk Maxwell, Oliver Heaviside, and Heinrich Hertz. The new theory raised questions that could not easily be answered using Newton's framework. The discovery of X-rays inspired the discovery of radioactivity by Henri Becquerel and Marie Curie in 1896, Marie Curie then became the first person to win two Nobel Prizes. In the next year came the discovery of the first subatomic particle, the electron. === 20th century === In the first half of the century the development of antibiotics and artificial fertilisers improved human living standards globally. Harmful environmental issues such as ozone depletion, ocean acidification, eutrophication, and climate change came to the public's attention and caused the onset of environmental studies. During this period scientific experimentation became increasingly larger in scale and funding. The extensive technological innovation stimulated by World War I, World War II, and the Cold War led to competitions between global powers, such as the Space Race and nuclear arms race. Substantial international collaborations were also made, despite armed conflicts. In the late 20th century active recruitment of women and elimination of sex discrimination greatly increased the number of women scientists, but large gender disparities remained in some fields. The discovery of the cosmic microwave background in 1964 led to a rejection of the steady-state model of the universe in favour of the Big Bang theory of Georges Lemaître. The century saw fundamental changes within science disciplines. Evolution became a unified theory in the early 20th-century when the modern synthesis reconciled Darwinian evolution with classical genetics. Albert Einstein's theory of relativity and the development of quantum mechanics complement classical mechanics to describe physics in extreme length, time and gravity. Widespread use of integrated circuits in the last quarter of the 20th century combined with communications satellites led to a revolution in information technology and the rise of the global internet and mobile computing, including smartphones. The need for mass systematisation of long, intertwined causal chains and large amounts of data led to the rise of the fields of systems theory and computer-assisted scientific modelling. === 21st century === The Human Genome Project was completed in 2003 by identifying and mapping all of the genes of the human genome. The first induced pluripotent human stem cells were made in 2006, allowing adult cells to be transformed into stem cells and turn into any cell type found in the body. With the affirmation of the Higgs boson discovery in 2013, the last particle predicted by the Standard Model of particle physics was found. In 2015, gravitational waves, predicted by general relativity a century before, were first observed. In 2019, the international collaboration Event Horizon Telescope presented the first direct image of a black hole's accretion disc. == Branches == Modern science is commonly divided into three major branches: natural science, social science, and formal science. Each of these branches comprises various specialised yet overlapping scientific disciplines that often possess their own nomenclature and expertise. Both natural and social sciences are empirical sciences, as their knowledge is based on empirical observations and is capable of being tested for its validity by other researchers working under the same conditions. === Natural science === Natural science is the study of the physical world. It can be divided into two main branches: life science and physical science. These two branches may be further divided into more specialised disciplines. For example, physical science can be subdivided into physics, chemistry, astronomy, and earth science. Modern natural science is the successor to the natural philosophy that began in Ancient Greece. Galileo, Descartes, Bacon, and Newton debated the benefits of using approaches that were more mathematical and more experimental in a methodical way. Still, philosophical perspectives, conjectures, and presuppositions, often overlooked, remain necessary in natural science. Systematic data collection, including discovery science, succeeded natural history, which emerged in the 16th century by describing and classifying plants, animals, minerals, and other biotic beings. Today, "natural history" suggests observational descriptions aimed at popular audiences. === Social science === Social science is the study of human behaviour and the functioning of societies. It has many disciplines that include, but are not limited to anthropology, economics, history, human geography, political science, psychology, and sociology. In the social sciences, there are many competing theoretical perspectives, many of which are extended through competing research programmes such as the functionalists, conflict theorists, and interactionists in sociology. Due to the limitations of conducting controlled experiments involving large groups of individuals or complex situations, social scientists may adopt other research methods such as the historical method, case studies, and cross-cultural studies. Moreover, if quantitative information is available, social scientists may rely on statistical approaches to better understand social relationships and processes. === Formal science === Formal science is an area of study that generates knowledge using formal systems. A formal system is an abstract structure used for inferring theorems from axioms according to a set of rules. It includes mathematics, systems theory, and theoretical computer science. The formal sciences share similarities with the other two branches by relying on objective, careful, and systematic study of an area of knowledge. They are, however, different from the empirical sciences as they rely exclusively on deductive reasoning, without the need for empirical evidence, to verify their abstract concepts. The formal sciences are therefore a priori disciplines and because of this, there is disagreement on whether they constitute a science. Nevertheless, the formal sciences play an important role in the empirical sciences. Calculus, for example, was initially invented to understand motion in physics. Natural and social sciences that rely heavily on mathematical applications include mathematical physics, chemistry, biology, finance, and economics. === Applied science === Applied science is the use of the scientific method and knowledge to attain practical goals and includes a broad range of disciplines such as engineering and medicine. Engineering is the use of scientific principles to invent, design and build machines, structures and technologies. Science may contribute to the development of new technologies. Medicine is the practice of caring for patients by maintaining and restoring health through the prevention, diagnosis, and treatment of injury or disease. === Basic sciences === The applied sciences are often contrasted with the basic sciences, which are focused on advancing scientific theories and laws that explain and predict events in the natural world. === Blue skies science === === Computational science === Computational science applies computer simulations to science, enabling a better understanding of scientific problems than formal mathematics alone can achieve. The use of machine learning and artificial intelligence is becoming a central feature of computational contributions to science, for example in agent-based computational economics, random forests, topic modeling and various forms of prediction. However, machines alone rarely advance knowledge as they require human guidance and capacity to reason; and they can introduce bias against certain social groups or sometimes underperform against humans. === Interdisciplinary science === Interdisciplinary science involves the combination of two or more disciplines into one, such as bioinformatics, a combination of biology and computer science or cognitive sciences. The concept has existed since the ancient Greek period and it became popular again in the 20th century. == Scientific research == Scientific research can be labelled as either basic or applied research. Basic research is the search for knowledge and applied research is the search for solutions to practical problems using this knowledge. Most understanding comes from basic research, though sometimes applied research targets specific practical problems. This leads to technological advances that were not previously imaginable. === Scientific method === Scientific research involves using the scientific method, which seeks to objectively explain the events of nature in a reproducible way. Scientists usually take for granted a set of basic assumptions that are needed to justify the scientific method: there is an objective reality shared by all rational observers; this objective reality is governed by natural laws; these laws were discovered by means of systematic observation and experimentation. Mathematics is essential in the formation of hypotheses, theories, and laws, because it is used extensively in quantitative modelling, observing, and collecting measurements. Statistics is used to summarise and analyse data, which allows scientists to assess the reliability of experimental results. In the scientific method an explanatory thought experiment or hypothesis is put forward as an explanation using parsimony principles and is expected to seek consilience – fitting with other accepted facts related to an observation or scientific question. This tentative explanation is used to make falsifiable predictions, which are typically posted before being tested by experimentation. Disproof of a prediction is evidence of progress.: 4–5 Experimentation is especially important in science to help establish causal relationships to avoid the correlation fallacy, though in some sciences such as astronomy or geology, a predicted observation might be more appropriate. When a hypothesis proves unsatisfactory it is modified or discarded. If the hypothesis survives testing, it may become adopted into the framework of a scientific theory, a validly reasoned, self-consistent model or framework for describing the behaviour of certain natural events. A theory typically describes the behaviour of much broader sets of observations than a hypothesis; commonly, a large number of hypotheses can be logically bound together by a single theory. Thus, a theory is a hypothesis explaining various other hypotheses. In that vein, theories are formulated according to most of the same scientific principles as hypotheses. Scientists may generate a model, an attempt to describe or depict an observation in terms of a logical, physical or mathematical representation, and to generate new hypotheses that can be tested by experimentation. While performing experiments to test hypotheses, scientists may have a preference for one outcome over another. Eliminating the bias can be achieved through transparency, careful experimental design, and a thorough peer review process of the experimental results and conclusions. After the results of an experiment are announced or published, it is normal practice for independent researchers to double-check how the research was performed, and to follow up by performing similar experiments to determine how dependable the results might be. Taken in its entirety, the scientific method allows for highly creative problem solving while minimising the effects of subjective and confirmation bias. Intersubjective verifiability, the ability to reach a consensus and reproduce results, is fundamental to the creation of all scientific knowledge. === Scientific literature === Scientific research is published in a range of literature. Scientific journals communicate and document the results of research carried out in universities and various other research institutions, serving as an archival record of science. The first scientific journals, Journal des sçavans followed by Philosophical Transactions, began publication in 1665. Since that time the total number of active periodicals has steadily increased. In 1981, one estimate for the number of scientific and technical journals in publication was 11,500. Most scientific journals cover a single scientific field and publish the research within that field; the research is normally expressed in the form of a scientific paper. Science has become so pervasive in modern societies that it is considered necessary to communicate the achievements, news, and ambitions of scientists to a wider population. === Challenges === The replication crisis is an ongoing methodological crisis that affects parts of the social and life sciences. In subsequent investigations, the results of many scientific studies have been proven to be unrepeatable. The crisis has long-standing roots; the phrase was coined in the early 2010s as part of a growing awareness of the problem. The replication crisis represents an important body of research in metascience, which aims to improve the quality of all scientific research while reducing waste. An area of study or speculation that masquerades as science in an attempt to claim legitimacy that it would not otherwise be able to achieve is sometimes referred to as pseudoscience, fringe science, or junk science. Physicist Richard Feynman coined the term "cargo cult science" for cases in which researchers believe, and at a glance, look like they are doing science but lack the honesty to allow their results to be rigorously evaluated. Various types of commercial advertising, ranging from hype to fraud, may fall into these categories. Science has been described as "the most important tool" for separating valid claims from invalid ones. There can also be an element of political bias or ideological bias on all sides of scientific debates. Sometimes, research may be characterised as "bad science", research that may be well-intended but is incorrect, obsolete, incomplete, or over-simplified expositions of scientific ideas. The term scientific misconduct refers to situations such as where researchers have intentionally misrepresented their published data or have purposely given credit for a discovery to the wrong person. == Philosophy of science == There are different schools of thought in the philosophy of science. The most popular position is empiricism, which holds that knowledge is created by a process involving observation; scientific theories generalise observations. Empiricism generally encompasses inductivism, a position that explains how general theories can be made from the finite amount of empirical evidence available. Many versions of empiricism exist, with the predominant ones being Bayesianism and the hypothetico-deductive method. Empiricism has stood in contrast to rationalism, the position originally associated with Descartes, which holds that knowledge is created by the human intellect, not by observation. Critical rationalism is a contrasting 20th-century approach to science, first defined by Austrian-British philosopher Karl Popper. Popper rejected the way that empiricism describes the connection between theory and observation. He claimed that theories are not generated by observation, but that observation is made in the light of theories, and that the only way theory A can be affected by observation is after theory A were to conflict with observation, but theory B were to survive the observation. Popper proposed replacing verifiability with falsifiability as the landmark of scientific theories, replacing induction with falsification as the empirical method. Popper further claimed that there is actually only one universal method, not specific to science: the negative method of criticism, trial and error, covering all products of the human mind, including science, mathematics, philosophy, and art. Another approach, instrumentalism, emphasises the utility of theories as instruments for explaining and predicting phenomena. It views scientific theories as black boxes, with only their input (initial conditions) and output (predictions) being relevant. Consequences, theoretical entities, and logical structure are claimed to be things that should be ignored. Close to instrumentalism is constructive empiricism, according to which the main criterion for the success of a scientific theory is whether what it says about observable entities is true. Thomas Kuhn argued that the process of observation and evaluation takes place within a paradigm, a logically consistent "portrait" of the world that is consistent with observations made from its framing. He characterised normal science as the process of observation and "puzzle solving", which takes place within a paradigm, whereas revolutionary science occurs when one paradigm overtakes another in a paradigm shift. Each paradigm has its own distinct questions, aims, and interpretations. The choice between paradigms involves setting two or more "portraits" against the world and deciding which likeness is most promising. A paradigm shift occurs when a significant number of observational anomalies arise in the old paradigm and a new paradigm makes sense of them. That is, the choice of a new paradigm is based on observations, even though those observations are made against the background of the old paradigm. For Kuhn, acceptance or rejection of a paradigm is a social process as much as a logical process. Kuhn's position, however, is not one of relativism. Another approach often cited in debates of scientific scepticism against controversial movements like "creation science" is methodological naturalism. Naturalists maintain that a difference should be made between natural and supernatural, and science should be restricted to natural explanations. Methodological naturalism maintains that science requires strict adherence to empirical study and independent verification. == Scientific community == The scientific community is a network of interacting scientists who conduct scientific research. The community consists of smaller groups working in scientific fields. By having peer review, through discussion and debate within journals and conferences, scientists maintain the quality of research methodology and objectivity when interpreting results. === Scientists === Scientists are individuals who conduct scientific research to advance knowledge in an area of interest. Scientists may exhibit a strong curiosity about reality and a desire to apply scientific knowledge for the benefit of public health, nations, the environment, or industries; other motivations include recognition by peers and prestige. In modern times, many scientists study within specific areas of science in academic institutions, often obtaining advanced degrees in the process. Many scientists pursue careers in various fields such as academia, industry, government, and nonprofit organisations. Science has historically been a male-dominated field, with notable exceptions. Women have faced considerable discrimination in science, much as they have in other areas of male-dominated societies. For example, women were frequently passed over for job opportunities and denied credit for their work. The achievements of women in science have been attributed to the defiance of their traditional role as labourers within the domestic sphere. === Learned societies === Learned societies for the communication and promotion of scientific thought and experimentation have existed since the Renaissance. Many scientists belong to a learned society that promotes their respective scientific discipline, profession, or group of related disciplines. Membership may either be open to all, require possession of scientific credentials, or conferred by election. Most scientific societies are nonprofit organisations, and many are professional associations. Their activities typically include holding regular conferences for the presentation and discussion of new research results and publishing or sponsoring academic journals in their discipline. Some societies act as professional bodies, regulating the activities of their members in the public interest, or the collective interest of the membership. The professionalisation of science, begun in the 19th century, was partly enabled by the creation of national distinguished academies of sciences such as the Italian Accademia dei Lincei in 1603, the British Royal Society in 1660, the French Academy of Sciences in 1666, the American National Academy of Sciences in 1863, the German Kaiser Wilhelm Society in 1911, and the Chinese Academy of Sciences in 1949. International scientific organisations, such as the International Science Council, are devoted to international cooperation for science advancement. === Awards === Science awards are usually given to individuals or organisations that have made significant contributions to a discipline. They are often given by prestigious institutions; thus, it is considered a great honour for a scientist receiving them. Since the early Renaissance, scientists have often been awarded medals, money, and titles. The Nobel Prize, a widely regarded prestigious award, is awarded annually to those who have achieved scientific advances in the fields of medicine, physics, and chemistry. == Society == === Funding and policies === Funding of science is often through a competitive process in which potential research projects are evaluated and only the most promising receive funding. Such processes, which are run by government, corporations, or foundations, allocate scarce funds. Total research funding in most developed countries is between 1.5% and 3% of GDP. In the OECD, around two-thirds of research and development in scientific and technical fields is carried out by industry, and 20% and 10%, respectively, by universities and government. The government funding proportion in certain fields is higher, and it dominates research in social science and the humanities. In less developed nations, the government provides the bulk of the funds for their basic scientific research. Many governments have dedicated agencies to support scientific research, such as the National Science Foundation in the United States, the National Scientific and Technical Research Council in Argentina, Commonwealth Scientific and Industrial Research Organisation in Australia, National Centre for Scientific Research in France, the Max Planck Society in Germany, and National Research Council in Spain. In commercial research and development, all but the most research-orientated corporations focus more heavily on near-term commercialisation possibilities than research driven by curiosity. Science policy is concerned with policies that affect the conduct of the scientific enterprise, including research funding, often in pursuance of other national policy goals such as technological innovation to promote commercial product development, weapons development, health care, and environmental monitoring. Science policy sometimes refers to the act of applying scientific knowledge and consensus to the development of public policies. In accordance with public policy being concerned about the well-being of its citizens, science policy's goal is to consider how science and technology can best serve the public. Public policy can directly affect the funding of capital equipment and intellectual infrastructure for industrial research by providing tax incentives to those organisations that fund research. === Education and awareness === Science education for the general public is embedded in the school curriculum, and is supplemented by online pedagogical content (for example, YouTube and Khan Academy), museums, and science magazines and blogs. Major organisations of scientists such as the American Association for the Advancement of Science (AAAS) consider the sciences to be a part of the liberal arts traditions of learning, along with philosophy and history. Scientific literacy is chiefly concerned with an understanding of the scientific method, units and methods of measurement, empiricism, a basic understanding of statistics (correlations, qualitative versus quantitative observations, aggregate statistics), and a basic understanding of core scientific fields such as physics, chemistry, biology, ecology, geology, and computation. As a student advances into higher stages of formal education, the curriculum becomes more in depth. Traditional subjects usually included in the curriculum are natural and formal sciences, although recent movements include social and applied science as well. The mass media face pressures that can prevent them from accurately depicting competing scientific claims in terms of their credibility within the scientific community as a whole. Determining how much weight to give different sides in a scientific debate may require considerable expertise regarding the matter. Few journalists have real scientific knowledge, and even beat reporters who are knowledgeable about certain scientific issues may be ignorant about other scientific issues that they are suddenly asked to cover. Science magazines such as New Scientist, Science & Vie, and Scientific American cater to the needs of a much wider readership and provide a non-technical summary of popular areas of research, including notable discoveries and advances in certain fields of research. The science fiction genre, primarily speculative fiction, can transmit the ideas and methods of science to the general public. Recent efforts to intensify or develop links between science and non-scientific disciplines, such as literature or poetry, include the Creative Writing Science resource developed through the Royal Literary Fund. === Anti-science attitudes === While the scientific method is broadly accepted in the scientific community, some fractions of society reject certain scientific positions or are sceptical about science. Examples are the common notion that COVID-19 is not a major health threat to the US (held by 39% of Americans in August 2021) or the belief that climate change is not a major threat to the US (also held by 40% of Americans, in late 2019 and early 2020). Psychologists have pointed to four factors driving rejection of scientific results: Scientific authorities are sometimes seen as inexpert, untrustworthy, or biased. Some marginalised social groups hold anti-science attitudes, in part because these groups have often been exploited in unethical experiments. Messages from scientists may contradict deeply held existing beliefs or morals. The delivery of a scientific message may not be appropriately targeted to a recipient's learning style. Anti-science attitudes often seem to be caused by fear of rejection in social groups. For instance, climate change is perceived as a threat by only 22% of Americans on the right side of the political spectrum, but by 85% on the left. That is, if someone on the left would not consider climate change as a threat, this person may face contempt and be rejected in that social group. In fact, people may rather deny a scientifically accepted fact than lose or jeopardise their social status. === Politics === Attitudes towards science are often determined by political opinions and goals. Government, business and advocacy groups have been known to use legal and economic pressure to influence scientific researchers. Many factors can act as facets of the politicisation of science such as anti-intellectualism, perceived threats to religious beliefs, and fear for business interests. Politicisation of science is usually accomplished when scientific information is presented in a way that emphasises the uncertainty associated with the scientific evidence. Tactics such as shifting conversation, failing to acknowledge facts, and capitalising on doubt of scientific consensus have been used to gain more attention for views that have been undermined by scientific evidence. Examples of issues that have involved the politicisation of science include the global warming controversy, health effects of pesticides, and health effects of tobacco. == See also == List of scientific occupations List of years in science Logology (science) Science (Wikiversity) Scientific integrity == Notes == == References == == External links ==
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https://en.wikipedia.org/wiki/Science
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A science ministry or department of science is a ministry or other government agency responsible for governing scientific activities. The ministry is often headed by a minister specialising in scientific matters. == List of ministries of science == Many countries have a ministry of science or ministry of science and technology: Ministry of Science, Technology and Productive Innovation (Argentina) Ministry of Science and Technology (Bangladesh) Ministry of Science and Technology (Brazil) Innovation, Science and Economic Development Canada Ministry of Science, Technology, Knowledge and Innovation (Chile) Ministry of Science and Technology (China) Ministry of Science, Technology and Environment (Cuba) Ministry of Science, Technology and Innovation of Denmark Ministry of Higher Education, Science and Culture (East Timor) Federal Ministry of Education and Research (Germany) Ministry of Education, Science and Culture (Iceland) Ministry of Science and Technology (India) Ministry of Research, Technology and Higher Education (Indonesia) Ministry of Science, Research and Technology (Iran) Department of Further and Higher Education, Research, Innovation and Science (Ireland) Ministry of Education, Culture, Sports, Science and Technology (Japan) Ministry of Education and Science (Lithuania) Ministry of Science and Technology (Malaysia) Ministry of Education and Science (Mongolia) Ministry of Science and Technology (Myanmar) Ministry of Education and Science (North Macedonia) Ministry of Science and Technology (Pakistan) Department of Science and Technology (Philippines) Ministry of Science, Technology and Higher Education (Portugal) Ministry of Science and Higher Education (Russia) Minister for Further Education, Higher Education and Science (Scotland) Ministry of Education and Science (Somaliland) Ministry of Science and ICT (South Korea) Ministry of Science, Innovation and Universities (Spain) Ministry of Science and Technology (Sri Lanka) Ministry of Science and Technology (Taiwan) Ministry of Science and Technology (Thailand) Ministry of Industry and Technology (Turkey) Ministry of Education and Science of Ukraine Ministry of Science and Technology (Vietnam) Ministry of Science And Technology (Robloz) Ministry of Technology and Science (Zambia) == Ministers of Science == This is a list of Ministers who have a policy responsibility over Science. Brazil: Ministry of Science, Technology and Innovation (Brazil): Marcos César Pontes Canada: Minister of Innovation, Science and Industry: Navdeep Bains Manitoba: Minister of Energy, Science and Technology (No longer used) China: Minister of Science and Technology: Yin Hejun Ireland: Minister for Further and Higher Education, Research, Innovation and Science: Simon Harris Japan: Minister of Education, Culture, Sports, Science and Technology: Kōichi Hagiuda Philippines: Secretary of Science and Technology: Fortunato dela Peña United Kingdom: Parliamentary Under Secretary of State for Science, Research and Innovation: Amanda Solloway Scotland: Minister for Further Education, Higher Education and Science: Richard Lochhead
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https://en.wikipedia.org/wiki/Ministry_of_science
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Economics () is a social science that studies the production, distribution, and consumption of goods and services. Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics analyses what is viewed as basic elements within economies, including individual agents and markets, their interactions, and the outcomes of interactions. Individual agents may include, for example, households, firms, buyers, and sellers. Macroeconomics analyses economies as systems where production, distribution, consumption, savings, and investment expenditure interact; and the factors of production affecting them, such as: labour, capital, land, and enterprise, inflation, economic growth, and public policies that impact these elements. It also seeks to analyse and describe the global economy. Other broad distinctions within economics include those between positive economics, describing "what is", and normative economics, advocating "what ought to be"; between economic theory and applied economics; between rational and behavioural economics; and between mainstream economics and heterodox economics. Economic analysis can be applied throughout society, including business, finance, cybersecurity, health care, engineering and government. It is also applied to such diverse subjects as crime, education, the family, feminism, law, philosophy, politics, religion, social institutions, war, science, and the environment. == Definitions of economics == The earlier term for the discipline was "political economy", but since the late 19th century, it has commonly been called "economics". The term is ultimately derived from Ancient Greek οἰκονομία (oikonomia) which is a term for the "way (nomos) to run a household (oikos)", or in other words the know-how of an οἰκονομικός (oikonomikos), or "household or homestead manager". Derived terms such as "economy" can therefore often mean "frugal" or "thrifty". By extension then, "political economy" was the way to manage a polis or state. There are a variety of modern definitions of economics; some reflect evolving views of the subject or different views among economists. Scottish philosopher Adam Smith (1776) defined what was then called political economy as "an inquiry into the nature and causes of the wealth of nations", in particular as: a branch of the science of a statesman or legislator [with the twofold objectives of providing] a plentiful revenue or subsistence for the people ... [and] to supply the state or commonwealth with a revenue for the publick services. Jean-Baptiste Say (1803), distinguishing the subject matter from its public-policy uses, defined it as the science of production, distribution, and consumption of wealth. On the satirical side, Thomas Carlyle (1849) coined "the dismal science" as an epithet for classical economics, in this context, commonly linked to the pessimistic analysis of Malthus (1798). John Stuart Mill (1844) delimited the subject matter further: The science which traces the laws of such of the phenomena of society as arise from the combined operations of mankind for the production of wealth, in so far as those phenomena are not modified by the pursuit of any other object. Alfred Marshall provided a still widely cited definition in his textbook Principles of Economics (1890) that extended analysis beyond wealth and from the societal to the microeconomic level: Economics is a study of man in the ordinary business of life. It enquires how he gets his income and how he uses it. Thus, it is on the one side, the study of wealth and on the other and more important side, a part of the study of man. Lionel Robbins (1932) developed implications of what has been termed "[p]erhaps the most commonly accepted current definition of the subject": Economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses. Robbins described the definition as not classificatory in "pick[ing] out certain kinds of behaviour" but rather analytical in "focus[ing] attention on a particular aspect of behaviour, the form imposed by the influence of scarcity." He affirmed that previous economists have usually centred their studies on the analysis of wealth: how wealth is created (production), distributed, and consumed; and how wealth can grow. But he said that economics can be used to study other things, such as war, that are outside its usual focus. This is because war has as the goal winning it (as a sought-after end), generates both cost and benefits; and, resources (human life and other costs) are used to attain the goal. If the war is not winnable or if the expected costs outweigh the benefits, the deciding actors (assuming they are rational) may never go to war (a decision) but rather explore other alternatives. Economics cannot be defined as the science that studies wealth, war, crime, education, and any other field economic analysis can be applied to; but, as the science that studies a particular common aspect of each of those subjects (they all use scarce resources to attain a sought-after end). Some subsequent comments criticised the definition as overly broad in failing to limit its subject matter to analysis of markets. From the 1960s, however, such comments abated as the economic theory of maximizing behaviour and rational-choice modelling expanded the domain of the subject to areas previously treated in other fields. There are other criticisms as well, such as in scarcity not accounting for the macroeconomics of high unemployment. Gary Becker, a contributor to the expansion of economics into new areas, described the approach he favoured as "combin[ing the] assumptions of maximizing behaviour, stable preferences, and market equilibrium, used relentlessly and unflinchingly." One commentary characterises the remark as making economics an approach rather than a subject matter but with great specificity as to the "choice process and the type of social interaction that [such] analysis involves." The same source reviews a range of definitions included in principles of economics textbooks and concludes that the lack of agreement need not affect the subject-matter that the texts treat. Among economists more generally, it argues that a particular definition presented may reflect the direction toward which the author believes economics is evolving, or should evolve. Many economists including Nobel Prize winners James M. Buchanan and Ronald Coase reject the method-based definition of Robbins and continue to prefer definitions like those of Say, in terms of its subject matter. Ha-Joon Chang has for example argued that the definition of Robbins would make economics very peculiar because all other sciences define themselves in terms of the area of inquiry or object of inquiry rather than the methodology. In the biology department, it is not said that all biology should be studied with DNA analysis. People study living organisms in many different ways, so some people will perform DNA analysis, others might analyse anatomy, and still others might build game theoretic models of animal behaviour. But they are all called biology because they all study living organisms. According to Ha Joon Chang, this view that the economy can and should be studied in only one way (for example by studying only rational choices), and going even one step further and basically redefining economics as a theory of everything, is peculiar. == History of economic thought == === From antiquity through the physiocrats === Questions regarding distribution of resources are found throughout the writings of the Boeotian poet Hesiod and several economic historians have described Hesiod as the "first economist". However, the word Oikos, the Greek word from which the word economy derives, was used for issues regarding how to manage a household (which was understood to be the landowner, his family, and his slaves) rather than to refer to some normative societal system of distribution of resources, which is a more recent phenomenon. Xenophon, the author of the Oeconomicus, is credited by philologues for being the source of the word economy. Joseph Schumpeter described 16th and 17th century scholastic writers, including Tomás de Mercado, Luis de Molina, and Juan de Lugo, as "coming nearer than any other group to being the 'founders' of scientific economics" as to monetary, interest, and value theory within a natural-law perspective. Two groups, who later were called "mercantilists" and "physiocrats", more directly influenced the subsequent development of the subject. Both groups were associated with the rise of economic nationalism and modern capitalism in Europe. Mercantilism was an economic doctrine that flourished from the 16th to 18th century in a prolific pamphlet literature, whether of merchants or statesmen. It held that a nation's wealth depended on its accumulation of gold and silver. Nations without access to mines could obtain gold and silver from trade only by selling goods abroad and restricting imports other than of gold and silver. The doctrine called for importing inexpensive raw materials to be used in manufacturing goods, which could be exported, and for state regulation to impose protective tariffs on foreign manufactured goods and prohibit manufacturing in the colonies. Physiocrats, a group of 18th-century French thinkers and writers, developed the idea of the economy as a circular flow of income and output. Physiocrats believed that only agricultural production generated a clear surplus over cost, so that agriculture was the basis of all wealth. Thus, they opposed the mercantilist policy of promoting manufacturing and trade at the expense of agriculture, including import tariffs. Physiocrats advocated replacing administratively costly tax collections with a single tax on income of land owners. In reaction against copious mercantilist trade regulations, the physiocrats advocated a policy of laissez-faire, which called for minimal government intervention in the economy. Adam Smith (1723–1790) was an early economic theorist. Smith was harshly critical of the mercantilists but described the physiocratic system "with all its imperfections" as "perhaps the purest approximation to the truth that has yet been published" on the subject. === Classical political economy === The publication of Adam Smith's The Wealth of Nations in 1776, has been described as "the effective birth of economics as a separate discipline." The book identified land, labour, and capital as the three factors of production and the major contributors to a nation's wealth, as distinct from the physiocratic idea that only agriculture was productive. Smith discusses potential benefits of specialisation by division of labour, including increased labour productivity and gains from trade, whether between town and country or across countries. His "theorem" that "the division of labor is limited by the extent of the market" has been described as the "core of a theory of the functions of firm and industry" and a "fundamental principle of economic organization." To Smith has also been ascribed "the most important substantive proposition in all of economics" and foundation of resource-allocation theory—that, under competition, resource owners (of labour, land, and capital) seek their most profitable uses, resulting in an equal rate of return for all uses in equilibrium (adjusted for apparent differences arising from such factors as training and unemployment). In an argument that includes "one of the most famous passages in all economics," Smith represents every individual as trying to employ any capital they might command for their own advantage, not that of the society, and for the sake of profit, which is necessary at some level for employing capital in domestic industry, and positively related to the value of produce. In this: He generally, indeed, neither intends to promote the public interest, nor knows how much he is promoting it. By preferring the support of domestic to that of foreign industry, he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. Nor is it always the worse for the society that it was no part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it. The Reverend Thomas Robert Malthus (1798) used the concept of diminishing returns to explain low living standards. Human population, he argued, tended to increase geometrically, outstripping the production of food, which increased arithmetically. The force of a rapidly growing population against a limited amount of land meant diminishing returns to labour. The result, he claimed, was chronically low wages, which prevented the standard of living for most of the population from rising above the subsistence level. Economist Julian Simon has criticised Malthus's conclusions. While Adam Smith emphasised production and income, David Ricardo (1817) focused on the distribution of income among landowners, workers, and capitalists. Ricardo saw an inherent conflict between landowners on the one hand and labour and capital on the other. He posited that the growth of population and capital, pressing against a fixed supply of land, pushes up rents and holds down wages and profits. Ricardo was also the first to state and prove the principle of comparative advantage, according to which each country should specialise in producing and exporting goods in that it has a lower relative cost of production, rather relying only on its own production. It has been termed a "fundamental analytical explanation" for gains from trade. Coming at the end of the classical tradition, John Stuart Mill (1848) parted company with the earlier classical economists on the inevitability of the distribution of income produced by the market system. Mill pointed to a distinct difference between the market's two roles: allocation of resources and distribution of income. The market might be efficient in allocating resources but not in distributing income, he wrote, making it necessary for society to intervene. Value theory was important in classical theory. Smith wrote that the "real price of every thing ... is the toil and trouble of acquiring it". Smith maintained that, with rent and profit, other costs besides wages also enter the price of a commodity. Other classical economists presented variations on Smith, termed the 'labour theory of value'. Classical economics focused on the tendency of any market economy to settle in a final stationary state made up of a constant stock of physical wealth (capital) and a constant population size. === Marxian economics === Marxist (later, Marxian) economics descends from classical economics and it derives from the work of Karl Marx. The first volume of Marx's major work, Das Kapital, was published in 1867. Marx focused on the labour theory of value and theory of surplus value. Marx wrote that they were mechanisms used by capital to exploit labour. The labour theory of value held that the value of an exchanged commodity was determined by the labour that went into its production, and the theory of surplus value demonstrated how workers were only paid a proportion of the value their work had created. Marxian economics was further developed by Karl Kautsky (1854–1938)'s The Economic Doctrines of Karl Marx and The Class Struggle (Erfurt Program), Rudolf Hilferding's (1877–1941) Finance Capital, Vladimir Lenin (1870–1924)'s The Development of Capitalism in Russia and Imperialism, the Highest Stage of Capitalism, and Rosa Luxemburg (1871–1919)'s The Accumulation of Capital. === Neoclassical economics === At its inception as a social science, economics was defined and discussed at length as the study of production, distribution, and consumption of wealth by Jean-Baptiste Say in his Treatise on Political Economy or, The Production, Distribution, and Consumption of Wealth (1803). These three items were considered only in relation to the increase or diminution of wealth, and not in reference to their processes of execution. Say's definition has survived in part up to the present, modified by substituting the word "wealth" for "goods and services" meaning that wealth may include non-material objects as well. One hundred and thirty years later, Lionel Robbins noticed that this definition no longer sufficed, because many economists were making theoretical and philosophical inroads in other areas of human activity. In his Essay on the Nature and Significance of Economic Science, he proposed a definition of economics as a study of human behaviour, subject to and constrained by scarcity, which forces people to choose, allocate scarce resources to competing ends, and economise (seeking the greatest welfare while avoiding the wasting of scarce resources). According to Robbins: "Economics is the science which studies human behavior as a relationship between ends and scarce means which have alternative uses". Robbins' definition eventually became widely accepted by mainstream economists, and found its way into current textbooks. Although far from unanimous, most mainstream economists would accept some version of Robbins' definition, even though many have raised serious objections to the scope and method of economics, emanating from that definition. A body of theory later termed "neoclassical economics" formed from about 1870 to 1910. The term "economics" was popularised by such neoclassical economists as Alfred Marshall and Mary Paley Marshall as a concise synonym for "economic science" and a substitute for the earlier "political economy". This corresponded to the influence on the subject of mathematical methods used in the natural sciences. Neoclassical economics systematically integrated supply and demand as joint determinants of both price and quantity in market equilibrium, influencing the allocation of output and income distribution. It rejected the classical economics' labour theory of value in favour of a marginal utility theory of value on the demand side and a more comprehensive theory of costs on the supply side. In the 20th century, neoclassical theorists departed from an earlier idea that suggested measuring total utility for a society, opting instead for ordinal utility, which posits behaviour-based relations across individuals. In microeconomics, neoclassical economics represents incentives and costs as playing a pervasive role in shaping decision making. An immediate example of this is the consumer theory of individual demand, which isolates how prices (as costs) and income affect quantity demanded. In macroeconomics it is reflected in an early and lasting neoclassical synthesis with Keynesian macroeconomics. Neoclassical economics is occasionally referred as orthodox economics whether by its critics or sympathisers. Modern mainstream economics builds on neoclassical economics but with many refinements that either supplement or generalise earlier analysis, such as econometrics, game theory, analysis of market failure and imperfect competition, and the neoclassical model of economic growth for analysing long-run variables affecting national income. Neoclassical economics studies the behaviour of individuals, households, and organisations (called economic actors, players, or agents), when they manage or use scarce resources, which have alternative uses, to achieve desired ends. Agents are assumed to act rationally, have multiple desirable ends in sight, limited resources to obtain these ends, a set of stable preferences, a definite overall guiding objective, and the capability of making a choice. There exists an economic problem, subject to study by economic science, when a decision (choice) is made by one or more players to attain the best possible outcome. === Keynesian economics === Keynesian economics derives from John Maynard Keynes, in particular his book The General Theory of Employment, Interest and Money (1936), which ushered in contemporary macroeconomics as a distinct field. The book focused on determinants of national income in the short run when prices are relatively inflexible. Keynes attempted to explain in broad theoretical detail why high labour-market unemployment might not be self-correcting due to low "effective demand" and why even price flexibility and monetary policy might be unavailing. The term "revolutionary" has been applied to the book in its impact on economic analysis. During the following decades, many economists followed Keynes' ideas and expanded on his works. John Hicks and Alvin Hansen developed the IS–LM model which was a simple formalisation of some of Keynes' insights on the economy's short-run equilibrium. Franco Modigliani and James Tobin developed important theories of private consumption and investment, respectively, two major components of aggregate demand. Lawrence Klein built the first large-scale macroeconometric model, applying the Keynesian thinking systematically to the US economy. === Post-WWII economics === Immediately after World War II, Keynesian was the dominant economic view of the United States establishment and its allies, Marxian economics was the dominant economic view of the Soviet Union nomenklatura and its allies. ==== Monetarism ==== Monetarism appeared in the 1950s and 1960s, its intellectual leader being Milton Friedman. Monetarists contended that monetary policy and other monetary shocks, as represented by the growth in the money stock, was an important cause of economic fluctuations, and consequently that monetary policy was more important than fiscal policy for purposes of stabilisation. Friedman was also skeptical about the ability of central banks to conduct a sensible active monetary policy in practice, advocating instead using simple rules such as a steady rate of money growth. Monetarism rose to prominence in the 1970s and 1980s, when several major central banks followed a monetarist-inspired policy, but was later abandoned because the results were unsatisfactory. ==== New classical economics ==== A more fundamental challenge to the prevailing Keynesian paradigm came in the 1970s from new classical economists like Robert Lucas, Thomas Sargent and Edward Prescott. They introduced the notion of rational expectations in economics, which had profound implications for many economic discussions, among which were the so-called Lucas critique and the presentation of real business cycle models. ==== New Keynesians ==== During the 1980s, a group of researchers appeared being called New Keynesian economists, including among others George Akerlof, Janet Yellen, Gregory Mankiw and Olivier Blanchard. They adopted the principle of rational expectations and other monetarist or new classical ideas such as building upon models employing micro foundations and optimizing behaviour, but simultaneously emphasised the importance of various market failures for the functioning of the economy, as had Keynes. Not least, they proposed various reasons that potentially explained the empirically observed features of price and wage rigidity, usually made to be endogenous features of the models, rather than simply assumed as in older Keynesian-style ones. ==== New neoclassical synthesis ==== After decades of often heated discussions between Keynesians, monetarists, new classical and new Keynesian economists, a synthesis emerged by the 2000s, often given the name the new neoclassical synthesis. It integrated the rational expectations and optimizing framework of the new classical theory with a new Keynesian role for nominal rigidities and other market imperfections like imperfect information in goods, labour and credit markets. The monetarist importance of monetary policy in stabilizing the economy and in particular controlling inflation was recognised as well as the traditional Keynesian insistence that fiscal policy could also play an influential role in affecting aggregate demand. Methodologically, the synthesis led to a new class of applied models, known as dynamic stochastic general equilibrium or DSGE models, descending from real business cycles models, but extended with several new Keynesian and other features. These models proved useful and influential in the design of modern monetary policy and are now standard workhorses in most central banks. ==== After the 2008 financial crisis ==== After the 2008 financial crisis, macroeconomic research has put greater emphasis on understanding and integrating the financial system into models of the general economy and shedding light on the ways in which problems in the financial sector can turn into major macroeconomic recessions. In this and other research branches, inspiration from behavioural economics has started playing a more important role in mainstream economic theory. Also, heterogeneity among the economic agents, e.g. differences in income, plays an increasing role in recent economic research. === Other schools and approaches === Other schools or trends of thought referring to a particular style of economics practised at and disseminated from well-defined groups of academicians that have become known worldwide, include the Freiburg School, the School of Lausanne, the Stockholm school and the Chicago school of economics. During the 1970s and 1980s mainstream economics was sometimes separated into the Saltwater approach of those universities along the Eastern and Western coasts of the US, and the Freshwater, or Chicago school approach. Within macroeconomics there is, in general order of their historical appearance in the literature; classical economics, neoclassical economics, Keynesian economics, the neoclassical synthesis, monetarism, new classical economics, New Keynesian economics and the new neoclassical synthesis. Beside the mainstream development of economic thought, various alternative or heterodox economic theories have evolved over time, positioning themselves in contrast to mainstream theory. These include: Austrian School, emphasizing human action, property rights and the freedom to contract and transact to have a thriving and successful economy. It also emphasises that the state should play as small role as possible (if any role) in the regulation of economic activity between two transacting parties. Friedrich Hayek and Ludwig von Mises are the two most prominent representatives of the Austrian school. Post-Keynesian economics concentrates on macroeconomic rigidities and adjustment processes. It is generally associated with the University of Cambridge and the work of Joan Robinson. Ecological economics like environmental economics studies the interactions between human economies and the ecosystems in which they are embedded, but in contrast to environmental economics takes an oppositional position towards general mainstream economic principles. A major difference between the two subdisciplines is their assumptions about the substitution possibilities between human-made and natural capital. Additionally, alternative developments include Marxian economics, constitutional economics, institutional economics, evolutionary economics, dependency theory, structuralist economics, world systems theory, econophysics, econodynamics, feminist economics and biophysical economics. Feminist economics emphasises the role that gender plays in economies, challenging analyses that render gender invisible or support gender-oppressive economic systems. The goal is to create economic research and policy analysis that is inclusive and gender-aware to encourage gender equality and improve the well-being of marginalised groups. == Methodology == === Theoretical research === Mainstream economic theory relies upon analytical economic models. When creating theories, the objective is to find assumptions which are at least as simple in information requirements, more precise in predictions, and more fruitful in generating additional research than prior theories. While neoclassical economic theory constitutes both the dominant or orthodox theoretical as well as methodological framework, economic theory can also take the form of other schools of thought such as in heterodox economic theories. In microeconomics, principal concepts include supply and demand, marginalism, rational choice theory, opportunity cost, budget constraints, utility, and the theory of the firm. Early macroeconomic models focused on modelling the relationships between aggregate variables, but as the relationships appeared to change over time macroeconomists, including new Keynesians, reformulated their models with microfoundations, in which microeconomic concepts play a major part. Sometimes an economic hypothesis is only qualitative, not quantitative. Expositions of economic reasoning often use two-dimensional graphs to illustrate theoretical relationships. At a higher level of generality, mathematical economics is the application of mathematical methods to represent theories and analyse problems in economics. Paul Samuelson's treatise Foundations of Economic Analysis (1947) exemplifies the method, particularly as to maximizing behavioural relations of agents reaching equilibrium. The book focused on examining the class of statements called operationally meaningful theorems in economics, which are theorems that can conceivably be refuted by empirical data. === Empirical research === Economic theories are frequently tested empirically, largely through the use of econometrics using economic data. The controlled experiments common to the physical sciences are difficult and uncommon in economics, and instead broad data is observationally studied; this type of testing is typically regarded as less rigorous than controlled experimentation, and the conclusions typically more tentative. However, the field of experimental economics is growing, and increasing use is being made of natural experiments. Statistical methods such as regression analysis are common. Practitioners use such methods to estimate the size, economic significance, and statistical significance ("signal strength") of the hypothesised relation(s) and to adjust for noise from other variables. By such means, a hypothesis may gain acceptance, although in a probabilistic, rather than certain, sense. Acceptance is dependent upon the falsifiable hypothesis surviving tests. Use of commonly accepted methods need not produce a final conclusion or even a consensus on a particular question, given different tests, data sets, and prior beliefs. Experimental economics has promoted the use of scientifically controlled experiments. This has reduced the long-noted distinction of economics from natural sciences because it allows direct tests of what were previously taken as axioms. In some cases these have found that the axioms are not entirely correct. In behavioural economics, psychologist Daniel Kahneman won the Nobel Prize in economics in 2002 for his and Amos Tversky's empirical discovery of several cognitive biases and heuristics. Similar empirical testing occurs in neuroeconomics. Another example is the assumption of narrowly selfish preferences versus a model that tests for selfish, altruistic, and cooperative preferences. These techniques have led some to argue that economics is a "genuine science". == Microeconomics == Microeconomics examines how entities, forming a market structure, interact within a market to create a market system. These entities include private and public players with various classifications, typically operating under scarcity of tradable units and regulation. The item traded may be a tangible product such as apples or a service such as repair services, legal counsel, or entertainment. Various market structures exist. In perfectly competitive markets, no participants are large enough to have the market power to set the price of a homogeneous product. In other words, every participant is a "price taker" as no participant influences the price of a product. In the real world, markets often experience imperfect competition. Forms of imperfect competition include monopoly (in which there is only one seller of a good), duopoly (in which there are only two sellers of a good), oligopoly (in which there are few sellers of a good), monopolistic competition (in which there are many sellers producing highly differentiated goods), monopsony (in which there is only one buyer of a good), and oligopsony (in which there are few buyers of a good). Firms under imperfect competition have the potential to be "price makers", which means that they can influence the prices of their products. In partial equilibrium method of analysis, it is assumed that activity in the market being analysed does not affect other markets. This method aggregates (the sum of all activity) in only one market. General-equilibrium theory studies various markets and their behaviour. It aggregates (the sum of all activity) across all markets. This method studies both changes in markets and their interactions leading towards equilibrium. === Production, cost, and efficiency === In microeconomics, production is the conversion of inputs into outputs. It is an economic process that uses inputs to create a commodity or a service for exchange or direct use. Production is a flow and thus a rate of output per period of time. Distinctions include such production alternatives as for consumption (food, haircuts, etc.) vs. investment goods (new tractors, buildings, roads, etc.), public goods (national defence, smallpox vaccinations, etc.) or private goods, and "guns" vs "butter". Inputs used in the production process include such primary factors of production as labour services, capital (durable produced goods used in production, such as an existing factory), and land (including natural resources). Other inputs may include intermediate goods used in production of final goods, such as the steel in a new car. Economic efficiency measures how well a system generates desired output with a given set of inputs and available technology. Efficiency is improved if more output is generated without changing inputs. A widely accepted general standard is Pareto efficiency, which is reached when no further change can make someone better off without making someone else worse off. The production–possibility frontier (PPF) is an expository figure for representing scarcity, cost, and efficiency. In the simplest case, an economy can produce just two goods (say "guns" and "butter"). The PPF is a table or graph (as at the right) that shows the different quantity combinations of the two goods producible with a given technology and total factor inputs, which limit feasible total output. Each point on the curve shows potential total output for the economy, which is the maximum feasible output of one good, given a feasible output quantity of the other good. Scarcity is represented in the figure by people being willing but unable in the aggregate to consume beyond the PPF (such as at X) and by the negative slope of the curve. If production of one good increases along the curve, production of the other good decreases, an inverse relationship. This is because increasing output of one good requires transferring inputs to it from production of the other good, decreasing the latter. The slope of the curve at a point on it gives the trade-off between the two goods. It measures what an additional unit of one good costs in units forgone of the other good, an example of a real opportunity cost. Thus, if one more Gun costs 100 units of butter, the opportunity cost of one Gun is 100 Butter. Along the PPF, scarcity implies that choosing more of one good in the aggregate entails doing with less of the other good. Still, in a market economy, movement along the curve may indicate that the choice of the increased output is anticipated to be worth the cost to the agents. By construction, each point on the curve shows productive efficiency in maximizing output for given total inputs. A point inside the curve (as at A), is feasible but represents production inefficiency (wasteful use of inputs), in that output of one or both goods could increase by moving in a northeast direction to a point on the curve. Examples cited of such inefficiency include high unemployment during a business-cycle recession or economic organisation of a country that discourages full use of resources. Being on the curve might still not fully satisfy allocative efficiency (also called Pareto efficiency) if it does not produce a mix of goods that consumers prefer over other points. Much applied economics in public policy is concerned with determining how the efficiency of an economy can be improved. Recognizing the reality of scarcity and then figuring out how to organise society for the most efficient use of resources has been described as the "essence of economics", where the subject "makes its unique contribution." === Specialisation === Specialisation is considered key to economic efficiency based on theoretical and empirical considerations. Different individuals or nations may have different real opportunity costs of production, say from differences in stocks of human capital per worker or capital/labour ratios. According to theory, this may give a comparative advantage in production of goods that make more intensive use of the relatively more abundant, thus relatively cheaper, input. Even if one region has an absolute advantage as to the ratio of its outputs to inputs in every type of output, it may still specialise in the output in which it has a comparative advantage and thereby gain from trading with a region that lacks any absolute advantage but has a comparative advantage in producing something else. It has been observed that a high volume of trade occurs among regions even with access to a similar technology and mix of factor inputs, including high-income countries. This has led to investigation of economies of scale and agglomeration to explain specialisation in similar but differentiated product lines, to the overall benefit of respective trading parties or regions. The general theory of specialisation applies to trade among individuals, farms, manufacturers, service providers, and economies. Among each of these production systems, there may be a corresponding division of labour with different work groups specializing, or correspondingly different types of capital equipment and differentiated land uses. An example that combines features above is a country that specialises in the production of high-tech knowledge products, as developed countries do, and trades with developing nations for goods produced in factories where labour is relatively cheap and plentiful, resulting in different in opportunity costs of production. More total output and utility thereby results from specializing in production and trading than if each country produced its own high-tech and low-tech products. Theory and observation set out the conditions such that market prices of outputs and productive inputs select an allocation of factor inputs by comparative advantage, so that (relatively) low-cost inputs go to producing low-cost outputs. In the process, aggregate output may increase as a by-product or by design. Such specialisation of production creates opportunities for gains from trade whereby resource owners benefit from trade in the sale of one type of output for other, more highly valued goods. A measure of gains from trade is the increased income levels that trade may facilitate. === Supply and demand === Prices and quantities have been described as the most directly observable attributes of goods produced and exchanged in a market economy. The theory of supply and demand is an organizing principle for explaining how prices coordinate the amounts produced and consumed. In microeconomics, it applies to price and output determination for a market with perfect competition, which includes the condition of no buyers or sellers large enough to have price-setting power. For a given market of a commodity, demand is the relation of the quantity that all buyers would be prepared to purchase at each unit price of the good. Demand is often represented by a table or a graph showing price and quantity demanded (as in the figure). Demand theory describes individual consumers as rationally choosing the most preferred quantity of each good, given income, prices, tastes, etc. A term for this is "constrained utility maximisation" (with income and wealth as the constraints on demand). Here, utility refers to the hypothesised relation of each individual consumer for ranking different commodity bundles as more or less preferred. The law of demand states that, in general, price and quantity demanded in a given market are inversely related. That is, the higher the price of a product, the less of it people would be prepared to buy (other things unchanged). As the price of a commodity falls, consumers move toward it from relatively more expensive goods (the substitution effect). In addition, purchasing power from the price decline increases ability to buy (the income effect). Other factors can change demand; for example an increase in income will shift the demand curve for a normal good outward relative to the origin, as in the figure. All determinants are predominantly taken as constant factors of demand and supply. Supply is the relation between the price of a good and the quantity available for sale at that price. It may be represented as a table or graph relating price and quantity supplied. Producers, for example business firms, are hypothesised to be profit maximisers, meaning that they attempt to produce and supply the amount of goods that will bring them the highest profit. Supply is typically represented as a function relating price and quantity, if other factors are unchanged. That is, the higher the price at which the good can be sold, the more of it producers will supply, as in the figure. The higher price makes it profitable to increase production. Just as on the demand side, the position of the supply can shift, say from a change in the price of a productive input or a technical improvement. The "Law of Supply" states that, in general, a rise in price leads to an expansion in supply and a fall in price leads to a contraction in supply. Here as well, the determinants of supply, such as price of substitutes, cost of production, technology applied and various factors inputs of production are all taken to be constant for a specific time period of evaluation of supply. Market equilibrium occurs where quantity supplied equals quantity demanded, the intersection of the supply and demand curves in the figure above. At a price below equilibrium, there is a shortage of quantity supplied compared to quantity demanded. This is posited to bid the price up. At a price above equilibrium, there is a surplus of quantity supplied compared to quantity demanded. This pushes the price down. The model of supply and demand predicts that for given supply and demand curves, price and quantity will stabilise at the price that makes quantity supplied equal to quantity demanded. Similarly, demand-and-supply theory predicts a new price-quantity combination from a shift in demand (as to the figure), or in supply. === Firms === People frequently do not trade directly on markets. Instead, on the supply side, they may work in and produce through firms. The most obvious kinds of firms are corporations, partnerships and trusts. According to Ronald Coase, people begin to organise their production in firms when the costs of doing business becomes lower than doing it on the market. Firms combine labour and capital, and can achieve far greater economies of scale (when the average cost per unit declines as more units are produced) than individual market trading. In perfectly competitive markets studied in the theory of supply and demand, there are many producers, none of which significantly influence price. Industrial organisation generalises from that special case to study the strategic behaviour of firms that do have significant control of price. It considers the structure of such markets and their interactions. Common market structures studied besides perfect competition include monopolistic competition, various forms of oligopoly, and monopoly. Managerial economics applies microeconomic analysis to specific decisions in business firms or other management units. It draws heavily from quantitative methods such as operations research and programming and from statistical methods such as regression analysis in the absence of certainty and perfect knowledge. A unifying theme is the attempt to optimise business decisions, including unit-cost minimisation and profit maximisation, given the firm's objectives and constraints imposed by technology and market conditions. === Uncertainty and game theory === Uncertainty in economics is an unknown prospect of gain or loss, whether quantifiable as risk or not. Without it, household behaviour would be unaffected by uncertain employment and income prospects, financial and capital markets would reduce to exchange of a single instrument in each market period, and there would be no communications industry. Given its different forms, there are various ways of representing uncertainty and modelling economic agents' responses to it. Game theory is a branch of applied mathematics that considers strategic interactions between agents, one kind of uncertainty. It provides a mathematical foundation of industrial organisation, discussed above, to model different types of firm behaviour, for example in a solipsistic industry (few sellers), but equally applicable to wage negotiations, bargaining, contract design, and any situation where individual agents are few enough to have perceptible effects on each other. In behavioural economics, it has been used to model the strategies agents choose when interacting with others whose interests are at least partially adverse to their own. In this, it generalises maximisation approaches developed to analyse market actors such as in the supply and demand model and allows for incomplete information of actors. The field dates from the 1944 classic Theory of Games and Economic Behavior by John von Neumann and Oskar Morgenstern. It has significant applications seemingly outside of economics in such diverse subjects as the formulation of nuclear strategies, ethics, political science, and evolutionary biology. Risk aversion may stimulate activity that in well-functioning markets smooths out risk and communicates information about risk, as in markets for insurance, commodity futures contracts, and financial instruments. Financial economics or simply finance describes the allocation of financial resources. It also analyses the pricing of financial instruments, the financial structure of companies, the efficiency and fragility of financial markets, financial crises, and related government policy or regulation. Some market organisations may give rise to inefficiencies associated with uncertainty. Based on George Akerlof's "Market for Lemons" article, the paradigm example is of a dodgy second-hand car market. Customers without knowledge of whether a car is a "lemon" depress its price below what a quality second-hand car would be. Information asymmetry arises here, if the seller has more relevant information than the buyer but no incentive to disclose it. Related problems in insurance are adverse selection, such that those at most risk are most likely to insure (say reckless drivers), and moral hazard, such that insurance results in riskier behaviour (say more reckless driving). Both problems may raise insurance costs and reduce efficiency by driving otherwise willing transactors from the market ("incomplete markets"). Moreover, attempting to reduce one problem, say adverse selection by mandating insurance, may add to another, say moral hazard. Information economics, which studies such problems, has relevance in subjects such as insurance, contract law, mechanism design, monetary economics, and health care. Applied subjects include market and legal remedies to spread or reduce risk, such as warranties, government-mandated partial insurance, restructuring or bankruptcy law, inspection, and regulation for quality and information disclosure. === Market failure === The term "market failure" encompasses several problems which may undermine standard economic assumptions. Although economists categorise market failures differently, the following categories emerge in the main texts. Information asymmetries and incomplete markets may result in economic inefficiency but also a possibility of improving efficiency through market, legal, and regulatory remedies, as discussed above. Natural monopoly, or the overlapping concepts of "practical" and "technical" monopoly, is an extreme case of failure of competition as a restraint on producers. Extreme economies of scale are one possible cause. Public goods are goods which are under-supplied in a typical market. The defining features are that people can consume public goods without having to pay for them and that more than one person can consume the good at the same time. Externalities occur where there are significant social costs or benefits from production or consumption that are not reflected in market prices. For example, air pollution may generate a negative externality, and education may generate a positive externality (less crime, etc.). Governments often tax and otherwise restrict the sale of goods that have negative externalities and subsidise or otherwise promote the purchase of goods that have positive externalities in an effort to correct the price distortions caused by these externalities. Elementary demand-and-supply theory predicts equilibrium but not the speed of adjustment for changes of equilibrium due to a shift in demand or supply. In many areas, some form of price stickiness is postulated to account for quantities, rather than prices, adjusting in the short run to changes on the demand side or the supply side. This includes standard analysis of the business cycle in macroeconomics. Analysis often revolves around causes of such price stickiness and their implications for reaching a hypothesised long-run equilibrium. Examples of such price stickiness in particular markets include wage rates in labour markets and posted prices in markets deviating from perfect competition. Some specialised fields of economics deal in market failure more than others. The economics of the public sector is one example. Much environmental economics concerns externalities or "public bads". Policy options include regulations that reflect cost–benefit analysis or market solutions that change incentives, such as emission fees or redefinition of property rights. === Welfare === Welfare economics uses microeconomics techniques to evaluate well-being from allocation of productive factors as to desirability and economic efficiency within an economy, often relative to competitive general equilibrium. It analyses social welfare, however measured, in terms of economic activities of the individuals that compose the theoretical society considered. Accordingly, individuals, with associated economic activities, are the basic units for aggregating to social welfare, whether of a group, a community, or a society, and there is no "social welfare" apart from the "welfare" associated with its individual units. == Macroeconomics == Macroeconomics, another branch of economics, examines the economy as a whole to explain broad aggregates and their interactions "top down", that is, using a simplified form of general-equilibrium theory. Such aggregates include national income and output, the unemployment rate, and price inflation and subaggregates like total consumption and investment spending and their components. It also studies effects of monetary policy and fiscal policy. Since at least the 1960s, macroeconomics has been characterised by further integration as to micro-based modelling of sectors, including rationality of players, efficient use of market information, and imperfect competition. This has addressed a long-standing concern about inconsistent developments of the same subject. Macroeconomic analysis also considers factors affecting the long-term level and growth of national income. Such factors include capital accumulation, technological change and labour force growth. === Growth === Growth economics studies factors that explain economic growth – the increase in output per capita of a country over a long period of time. The same factors are used to explain differences in the level of output per capita between countries, in particular why some countries grow faster than others, and whether countries converge at the same rates of growth. Much-studied factors include the rate of investment, population growth, and technological change. These are represented in theoretical and empirical forms (as in the neoclassical and endogenous growth models) and in growth accounting. === Business cycle === The economics of a depression were the spur for the creation of "macroeconomics" as a separate discipline. During the Great Depression of the 1930s, John Maynard Keynes authored a book entitled The General Theory of Employment, Interest and Money outlining the key theories of Keynesian economics. Keynes contended that aggregate demand for goods might be insufficient during economic downturns, leading to unnecessarily high unemployment and losses of potential output. He therefore advocated active policy responses by the public sector, including monetary policy actions by the central bank and fiscal policy actions by the government to stabilise output over the business cycle. Thus, a central conclusion of Keynesian economics is that, in some situations, no strong automatic mechanism moves output and employment towards full employment levels. John Hicks' IS/LM model has been the most influential interpretation of The General Theory. Over the years, understanding of the business cycle has branched into various research programmes, mostly related to or distinct from Keynesianism. The neoclassical synthesis refers to the reconciliation of Keynesian economics with classical economics, stating that Keynesianism is correct in the short run but qualified by classical-like considerations in the intermediate and long run. New classical macroeconomics, as distinct from the Keynesian view of the business cycle, posits market clearing with imperfect information. It includes Friedman's permanent income hypothesis on consumption and "rational expectations" theory, led by Robert Lucas, and real business cycle theory. In contrast, the new Keynesian approach retains the rational expectations assumption, however it assumes a variety of market failures. In particular, New Keynesians assume prices and wages are "sticky", which means they do not adjust instantaneously to changes in economic conditions. Thus, the new classicals assume that prices and wages adjust automatically to attain full employment, whereas the new Keynesians see full employment as being automatically achieved only in the long run, and hence government and central-bank policies are needed because the "long run" may be very long. === Unemployment === The amount of unemployment in an economy is measured by the unemployment rate, the percentage of workers without jobs in the labour force. The labour force only includes workers actively looking for jobs. People who are retired, pursuing education, or discouraged from seeking work by a lack of job prospects are excluded from the labour force. Unemployment can be generally broken down into several types that are related to different causes. Classical models of unemployment occurs when wages are too high for employers to be willing to hire more workers. Consistent with classical unemployment, frictional unemployment occurs when appropriate job vacancies exist for a worker, but the length of time needed to search for and find the job leads to a period of unemployment. Structural unemployment covers a variety of possible causes of unemployment including a mismatch between workers' skills and the skills required for open jobs. Large amounts of structural unemployment can occur when an economy is transitioning industries and workers find their previous set of skills are no longer in demand. Structural unemployment is similar to frictional unemployment since both reflect the problem of matching workers with job vacancies, but structural unemployment covers the time needed to acquire new skills not just the short term search process. While some types of unemployment may occur regardless of the condition of the economy, cyclical unemployment occurs when growth stagnates. Okun's law represents the empirical relationship between unemployment and economic growth. The original version of Okun's law states that a 3% increase in output would lead to a 1% decrease in unemployment. === Money and monetary policy === Money is a means of final payment for goods in most price system economies, and is the unit of account in which prices are typically stated. Money has general acceptability, relative consistency in value, divisibility, durability, portability, elasticity in supply, and longevity with mass public confidence. It includes currency held by the nonbank public and checkable deposits. It has been described as a social convention, like language, useful to one largely because it is useful to others. In the words of Francis Amasa Walker, a well-known 19th-century economist, "Money is what money does" ("Money is that money does" in the original). As a medium of exchange, money facilitates trade. It is essentially a measure of value and more importantly, a store of value being a basis for credit creation. Its economic function can be contrasted with barter (non-monetary exchange). Given a diverse array of produced goods and specialised producers, barter may entail a hard-to-locate double coincidence of wants as to what is exchanged, say apples and a book. Money can reduce the transaction cost of exchange because of its ready acceptability. Then it is less costly for the seller to accept money in exchange, rather than what the buyer produces. Monetary policy is the policy that central banks conduct to accomplish their broader objectives. Most central banks in developed countries follow inflation targeting, whereas the main objective for many central banks in development countries is to uphold a fixed exchange rate system. The primary monetary tool is normally the adjustment of interest rates, either directly via administratively changing the central bank's own interest rates or indirectly via open market operations. Via the monetary transmission mechanism, interest rate changes affect investment, consumption and net export, and hence aggregate demand, output and employment, and ultimately the development of wages and inflation. === Fiscal policy === Governments implement fiscal policy to influence macroeconomic conditions by adjusting spending and taxation policies to alter aggregate demand. When aggregate demand falls below the potential output of the economy, there is an output gap where some productive capacity is left unemployed. Governments increase spending and cut taxes to boost aggregate demand. Resources that have been idled can be used by the government. For example, unemployed home builders can be hired to expand highways. Tax cuts allow consumers to increase their spending, which boosts aggregate demand. Both tax cuts and spending have multiplier effects where the initial increase in demand from the policy percolates through the economy and generates additional economic activity. The effects of fiscal policy can be limited by crowding out. When there is no output gap, the economy is producing at full capacity and there are no excess productive resources. If the government increases spending in this situation, the government uses resources that otherwise would have been used by the private sector, so there is no increase in overall output. Some economists think that crowding out is always an issue while others do not think it is a major issue when output is depressed. Sceptics of fiscal policy also make the argument of Ricardian equivalence. They argue that an increase in debt will have to be paid for with future tax increases, which will cause people to reduce their consumption and save money to pay for the future tax increase. Under Ricardian equivalence, any boost in demand from tax cuts will be offset by the increased saving intended to pay for future higher taxes. === Inequality === Economic inequality includes income inequality, measured using the distribution of income (the amount of money people receive), and wealth inequality measured using the distribution of wealth (the amount of wealth people own), and other measures such as consumption, land ownership, and human capital. Inequality exists at different extents between countries or states, groups of people, and individuals. There are many methods for measuring inequality, the Gini coefficient being widely used for income differences among individuals. An example measure of inequality between countries is the Inequality-adjusted Human Development Index, a composite index that takes inequality into account. Important concepts of equality include equity, equality of outcome, and equality of opportunity. Research has linked economic inequality to political and social instability, including revolution, democratic breakdown and civil conflict. Research suggests that greater inequality hinders economic growth and macroeconomic stability, and that land and human capital inequality reduce growth more than inequality of income. Inequality is at the centre stage of economic policy debate across the globe, as government tax and spending policies have significant effects on income distribution. In advanced economies, taxes and transfers decrease income inequality by one-third, with most of this being achieved via public social spending (such as pensions and family benefits.) == Other branches of economics == === Public economics === Public economics is the field of economics that deals with economic activities of a public sector, usually government. The subject addresses such matters as tax incidence (who really pays a particular tax), cost–benefit analysis of government programmes, effects on economic efficiency and income distribution of different kinds of spending and taxes, and fiscal politics. The latter, an aspect of public choice theory, models public-sector behaviour analogously to microeconomics, involving interactions of self-interested voters, politicians, and bureaucrats. Much of economics is positive, seeking to describe and predict economic phenomena. Normative economics seeks to identify what economies ought to be like. Welfare economics is a normative branch of economics that uses microeconomic techniques to simultaneously determine the allocative efficiency within an economy and the income distribution associated with it. It attempts to measure social welfare by examining the economic activities of the individuals that comprise society. === International economics === International trade studies determinants of goods-and-services flows across international boundaries. It also concerns the size and distribution of gains from trade. Policy applications include estimating the effects of changing tariff rates and trade quotas. International finance is a macroeconomic field which examines the flow of capital across international borders, and the effects of these movements on exchange rates. Increased trade in goods, services and capital between countries is a major effect of contemporary globalisation. === Labour economics === Labour economics seeks to understand the functioning and dynamics of the markets for wage labour. Labour markets function through the interaction of workers and employers. Labour economics looks at the suppliers of labour services (workers), the demands of labour services (employers), and attempts to understand the resulting pattern of wages, employment, and income. In economics, labour is a measure of the work done by human beings. It is conventionally contrasted with such other factors of production as land and capital. There are theories which have developed a concept called human capital (referring to the skills that workers possess, not necessarily their actual work), although there are also counter posing macro-economic system theories that think human capital is a contradiction in terms. === Development economics === Development economics examines economic aspects of the economic development process in relatively low-income countries focusing on structural change, poverty, and economic growth. Approaches in development economics frequently incorporate social and political factors. == Related subjects == Economics is one social science among several and has fields bordering on other areas, including economic geography, economic history, public choice, energy economics, cultural economics, family economics and institutional economics. Law and economics, or economic analysis of law, is an approach to legal theory that applies methods of economics to law. It includes the use of economic concepts to explain the effects of legal rules, to assess which legal rules are economically efficient, and to predict what the legal rules will be. A seminal article by Ronald Coase published in 1961 suggested that well-defined property rights could overcome the problems of externalities. Political economy is the interdisciplinary study that combines economics, law, and political science in explaining how political institutions, the political environment, and the economic system (capitalist, socialist, mixed) influence each other. It studies questions such as how monopoly, rent-seeking behaviour, and externalities should impact government policy. Historians have employed political economy to explore the ways in the past that persons and groups with common economic interests have used politics to effect changes beneficial to their interests. Energy economics is a broad scientific subject area which includes topics related to energy supply and energy demand. Georgescu-Roegen reintroduced the concept of entropy in relation to economics and energy from thermodynamics, as distinguished from what he viewed as the mechanistic foundation of neoclassical economics drawn from Newtonian physics. His work contributed significantly to thermoeconomics and to ecological economics. He also did foundational work which later developed into evolutionary economics. The sociological subfield of economic sociology arose, primarily through the work of Émile Durkheim, Max Weber and Georg Simmel, as an approach to analysing the effects of economic phenomena in relation to the overarching social paradigm (i.e. modernity). Classic works include Max Weber's The Protestant Ethic and the Spirit of Capitalism (1905) and Georg Simmel's The Philosophy of Money (1900). More recently, the works of James S. Coleman, Mark Granovetter, Peter Hedstrom and Richard Swedberg have been influential in this field. Gary Becker in 1974 presented an economic theory of social interactions, whose applications included the family, charity, merit goods and multiperson interactions, and envy and hatred. He and Kevin Murphy authored a book in 2001 that analysed market behaviour in a social environment. == Profession == The professionalisation of economics, reflected in the growth of graduate programmes on the subject, has been described as "the main change in economics since around 1900". Most major universities and many colleges have a major, school, or department in which academic degrees are awarded in the subject, whether in the liberal arts, business, or for professional study. See Bachelor of Economics and Master of Economics. In the private sector, professional economists are employed as consultants and in industry, including banking and finance. Economists also work for various government departments and agencies, for example, the national treasury, central bank or National Bureau of Statistics. See Economic analyst. There are dozens of prizes awarded to economists each year for outstanding intellectual contributions to the field, the most prominent of which is the Nobel Memorial Prize in Economic Sciences, though it is not a Nobel Prize. Contemporary economics uses mathematics. Economists draw on the tools of calculus, linear algebra, statistics, game theory, and computer science. Professional economists are expected to be familiar with these tools, while a minority specialise in econometrics and mathematical methods. === Women in economics === Harriet Martineau (1802–1876) was a widely-read populariser of classical economic thought. Mary Paley Marshall (1850–1944), the first women lecturer at a British economics faculty, wrote The Economics of Industry with her husband Alfred Marshall. Joan Robinson (1903–1983) was an important post-Keynesian economist. The economic historian Anna Schwartz (1915–2012) coauthored A Monetary History of the United States, 1867–1960 with Milton Friedman. Three women have received the Nobel Prize in Economics: Elinor Ostrom (2009), Esther Duflo (2019) and Claudia Goldin (2023). Five have received the John Bates Clark Medal: Susan Athey (2007), Esther Duflo (2010), Amy Finkelstein (2012), Emi Nakamura (2019) and Melissa Dell (2020). Women's authorship share in prominent economic journals reduced from 1940 to the 1970s, but has subsequently risen, with different patterns of gendered coauthorship. Women remain globally under-represented in the profession (19% of authors in the RePEc database in 2018), with national variation. == See also == == Notes == == References == === Sources === Hoover, Kevin D.; Siegler, Mark V. (20 March 2008). "Sound and Fury: McCloskey and Significance Testing in Economics". Journal of Economic Methodology. 15 (1): 1–37. CiteSeerX 10.1.1.533.7658. doi:10.1080/13501780801913298. S2CID 216137286. Samuelson, Paul A; Nordhaus, William D. (2010). Economics. Boston: Irwin McGraw-Hill. ISBN 978-0073511290. OCLC 751033918. == Further reading == Anderson, David A. (2019). Survey of Economics. New York: Worth. ISBN 978-1-4292-5956-9. Blanchard, Olivier; Amighini, Alessia; Giavazzi, Francesco (2017). Macroeconomics: a European perspective (3rd ed.). Pearson. ISBN 978-1-292-08567-8. Blaug, Mark (1985). Economic Theory in Retrospect (4th ed.). Cambridge: Cambridge University Press. ISBN 978-0521316446. McCann, Charles Robert Jr. (2003). The Elgar Dictionary of Economic Quotations. Edward Elgar. ISBN 978-1840648201. Post, Louis F. (1927), The Basic Facts of Economics: A Common-Sense Primer for Advanced Students. United States: Columbian Printing Company, Incorporated. Economics public domain audiobook at LibriVox. == External links == === General information === === Institutions and organizations === === Study resources ===
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Musicology is the academic, research-based study of music, as opposed to musical composition or performance. Musicology research combines and intersects with many fields, including psychology, sociology, acoustics, neurology, natural sciences, formal sciences and computer science. Musicology is traditionally divided into three branches: music history, systematic musicology, and ethnomusicology. Historical musicologists study the history of musical traditions, the origins of works, and the biographies of composers. Ethnomusicologists draw from anthropology (particularly field research) to understand how and why people make music. Systematic musicology includes music theory, aesthetics, pedagogy, musical acoustics, the science and technology of musical instruments, and the musical implications of physiology, psychology, sociology, philosophy and computing. Cognitive musicology is the set of phenomena surrounding the cognitive modeling of music. When musicologists carry out research using computers, their research often falls under the field of computational musicology. Music therapy is a specialized form of applied musicology which is sometimes considered more closely affiliated with health fields, and other times regarded as part of musicology proper. == Background == The word musicology comes from Greek μουσική mousikē 'music' and -λογια -logia, 'domain of study'. The 19th-century philosophical trends that led to the re-establishment of formal musicology education in German and Austrian universities had combined methods of systematization with evolution. These models were established not only in the field of physical anthropology, but also cultural anthropology. This was influenced by Hegel's ideas on ordering "phenomena" which can be understood & distinguished from simple to complex stages of evolution. They are further classified into primitive & developed sections; whereas the particular stages of history are understood & distinguished as ancient to modern. Comparative methods became more widespread in musicology beginning around 1880. == Parent disciplines == The parent disciplines of musicology include: General history Cultural studies Philosophy (particularly aesthetics and semiotics) Ethnology and cultural anthropology Archaeology and prehistory Psychology and sociology Physiology and neuroscience Acoustics and psychoacoustics Information sciences and mathematics Musicology also has two central, practically oriented sub-disciplines with no parent discipline: performance practice and research, and the theory, analysis and composition of music. The disciplinary neighbors of musicology address other forms of art, performance, ritual, and communication, including the history and theory of the visual and plastic arts and architecture; linguistics, literature and theater; religion and theology; and sport. Musical knowledge is applied within medicine, education and music therapy—which, effectively, are parent disciplines of applied musicology. == Subdisciplines == === Historical musicology === Music history or historical musicology is concerned with the composition, performance, reception and criticism of music over time. Historical studies of music are for example concerned with a composer's life and works, the developments of styles and genres (such as baroque concertos), the social function of music for a particular group of people, (such as court music), or modes of performance at a particular place and time (such as Johann Sebastian Bach's choir in Leipzig). Like the comparable field of art history, different branches and schools of historical musicology emphasize different types of musical works and approaches to music. There are also national differences in various definitions of historical musicology. In theory, "music history" could refer to the study of the history of any type or genre of music, such as the music of India or rock music. In practice, these research topics are more often considered within ethnomusicology and "historical musicology" is typically assumed to imply Western Art music of the European tradition. The methods of historical musicology include source studies (especially manuscript studies), palaeography, philology (especially textual criticism), style criticism, historiography (the choice of historical method), musical analysis (analysis of music to find "inner coherence") and iconography. The application of musical analysis to further these goals is often a part of music history, though pure analysis or the development of new tools of music analysis is more likely to be seen in the field of music theory. Music historians create a number of written products, ranging from journal articles describing their current research, new editions of musical works, biographies of composers and other musicians, book-length studies or university textbook chapters or entire textbooks. Music historians may examine issues in a close focus, as in the case of scholars who examine the relationship between words and music for a given composer's art songs. On the other hand, some scholars take a broader view and assess the place of a given type of music, such as the symphony in society using techniques drawn from other fields, such as economics, sociology or philosophy. === New musicology === New musicology is a term applied since the late 1980s to a wide body of work emphasizing cultural study, analysis and criticism of music. Such work may be based on feminist, gender studies, queer theory or postcolonial theory, or the work of Theodor W. Adorno. Although New Musicology emerged from within historical musicology, the emphasis on cultural study within the Western art music tradition places New Musicology at the junction between historical, ethnological and sociological research in music. New musicology was a reaction against traditional historical musicology, which according to Susan McClary, "fastidiously declares issues of musical signification off-limits to those engaged in legitimate scholarship." Charles Rosen, however, retorts that McClary, "sets up, like so many of the 'new musicologists', a straw man to knock down, the dogma that music has no meaning, and no political or social significance." Today, many musicologists no longer distinguish between musicology and new musicology since it has been recognized that many of the scholarly concerns once associated with new musicology already were mainstream in musicology, so that the term "new" no longer applies. === Ethnomusicology === Ethnomusicology, formerly comparative musicology, is the study of music in its cultural context. It is often considered the anthropology or ethnography of music. Jeff Todd Titon has called it the study of "people making music". Although it is most often concerned with the study of non-Western music, it also includes the study of Western music from an anthropological or sociological perspective, cultural studies and sociology as well as other disciplines in the social sciences and humanities. Some ethnomusicologists primarily conduct historical studies, but the majority are involved in long-term participant observation or combine ethnographic, musicological, and historical approaches in their fieldwork. Therefore, ethnomusicological scholarship can be characterized as featuring a substantial, intensive fieldwork component, often involving long-term residence within the community studied. Closely related to ethnomusicology is the emerging branch of sociomusicology. For instance, Ko (2011) proposed the hypothesis of "Biliterate and Trimusical" in Hong Kong sociomusicology. === Popular music studies === Popular music studies, known, "misleadingly", as popular musicology, emerged in the 1980s as an increasing number of musicologists, ethnomusicologists and other varieties of historians of American and European culture began to write about popular music past and present. The first journal focusing on popular music studies was Popular Music which began publication in 1981. The same year an academic society solely devoted to the topic was formed, the International Association for the Study of Popular Music. The association's founding was partly motivated by the interdisciplinary agenda of popular musicology though the group has been characterized by a polarized 'musicological' and 'sociological' approach also typical of popular musicology. === Music theory, analysis and composition === Music theory is a field of study that describes the elements of music and includes the development and application of methods for composing and for analyzing music through both notation and, on occasion, musical sound itself. Broadly, theory may include any statement, belief or conception of or about music (Boretz, 1995). A person who studies or practices music theory is a music theorist. Some music theorists attempt to explain the techniques composers use by establishing rules and patterns. Others model the experience of listening to or performing music. Though extremely diverse in their interests and commitments, many Western music theorists are united in their belief that the acts of composing, performing and listening to music may be explicated to a high degree of detail (this, as opposed to a conception of musical expression as fundamentally ineffable except in musical sounds). Generally, works of music theory are both descriptive and prescriptive, attempting both to define practice and to influence later practice. Musicians study music theory to understand the structural relationships in the (nearly always notated) music. Composers study music theory to understand how to produce effects and structure their own works. Composers may study music theory to guide their precompositional and compositional decisions. Broadly speaking, music theory in the Western tradition focuses on harmony and counterpoint, and then uses these to explain large scale structure and the creation of melody. === Music psychology === Music psychology applies the content and methods of psychology to understand how music is created, perceived, responded to, and incorporated into individuals' and societies' daily lives. Its primary branches include cognitive musicology, which emphasizes the use of computational models for human musical abilities and cognition, and the cognitive neuroscience of music, which studies the way that music perception and production manifests in the brain using the methodologies of cognitive neuroscience. While aspects of the field can be highly theoretical, much of modern music psychology seeks to optimize the practices and professions of music performance, composition, education and therapy. === Performance practice and research === Performance practice draws on many of the tools of historical musicology to answer the specific question of how music was performed in various places at various times in the past. Although previously confined to early music, recent research in performance practice has embraced questions such as how the early history of recording affected the use of vibrato in classical music or instruments in Klezmer. Within the rubric of musicology, performance practice tends to emphasize the collection and synthesis of evidence about how music should be performed. The important other side, learning how to sing authentically or perform a historical instrument is usually part of conservatory or other performance training. However, many top researchers in performance practice are also excellent musicians. Music performance research (or music performance science) is strongly associated with music psychology. It aims to document and explain the psychological, physiological, sociological and cultural details of how music is actually performed (rather than how it should be performed). The approach to research tends to be systematic and empirical and to involve the collection and analysis of both quantitative and qualitative data. The findings of music performance research can often be applied in music education. == Education and careers == Musicologists in tenure track professor positions typically hold a PhD in musicology. In the 1960s and 1970s, some musicologists obtained professor positions with an MA as their highest degree, but in the 2010s, the PhD is the standard minimum credential for tenure track professor positions. As part of their initial training, musicologists typically complete a BMus or a BA in music (or a related field such as history) and in many cases an MA in musicology. Some individuals apply directly from a bachelor's degree to a PhD, and in these cases, they may not receive an MA. In the 2010s, given the increasingly interdisciplinary nature of university graduate programs, some applicants for musicology PhD programs may have academic training both in music and outside of music (e.g., a student may apply with a BMus and an MA in psychology). In music education, individuals may hold an M.Ed and an Ed.D. Most musicologists work as instructors, lecturers or professors in colleges, [universities or conservatories. The job market for tenure track professor positions is very competitive. Entry-level applicants must hold a completed PhD or the equivalent degree and applicants to more senior professor positions must have a strong record of publishing in peer-reviewed journals. Some PhD-holding musicologists are only able to find insecure positions as sessional lecturers. The job tasks of a musicologist are the same as those of a professor in any other humanities discipline: teaching undergraduate and/or graduate classes in their area of specialization and, in many cases some general courses (such as Music Appreciation or Introduction to Music History); conducting research in their area of expertise, publishing articles about their research in peer-reviewed journals, authors book chapters, books or textbooks; traveling to conferences to give talks on their research and learn about research in their field; and, if their program includes a graduate school, supervising MA and PhD students, giving them guidance on the preparation of their theses and dissertations. Some musicology professors may take on senior administrative positions in their institution, such as Dean or Chair of the School of Music. == Notable journals == 19th-Century Music (1977–present) Acta Musicologica (1928–2014) (International Musicological Society) Asian Music (1968–2002) BACH: Journal of the Riemenschneider Bach Institute (1970–present) Black Music Research Journal (1980–2004) Early Music History (1981–2002) Ethnomusicology (1953–2003) (Society for Ethnomusicology) Journal of Music Theory (1957–2002) The Journal of Musicology (1982–2004) Journal of the American Musicological Society (1948–present) (American Musicological Society) Journal of the Royal Musical Association Journal of the Society for American Music Musica Disciplina (1946–present) Music Educators Journal (1934–2007) Music Theory Spectrum (1979–present) (Society for Music Theory) The Musical Quarterly (1915–present) Perspectives of New Music (1962–present) The World of Music (1957−present) Yearbook for Traditional Music (1981–2003) == Role of women == The vast majority of major musicologists and music historians from past generations have been men, as in the 19th century and early 20th century; women's involvement in teaching music was mainly in elementary and secondary music teaching. Nevertheless, some women musicologists have reached the top ranks of the profession. Carolyn Abbate (born 1956) is an American musicologist who did her PhD at Princeton University. She has been described by the Harvard Gazette as "one of the world's most accomplished and admired music historians". Susan McClary (born 1946) is a musicologist associated with new musicology who incorporates feminist music criticism in her work. McClary holds a PhD from Harvard University. One of her best known works is Feminine Endings (1991), which covers musical constructions of gender and sexuality, gendered aspects of traditional music theory, gendered sexuality in musical narrative, music as a gendered discourse and issues affecting women musicians. Other notable women scholars include: == See also == == References == == Further reading == == External links == International Musicological Society (IMS) The American Musicological Society AMS: Web sites of interest to Musicologists Archived 2020-01-27 at the Wayback Machine The Society for American Music International Association for the Study of Popular Music Society for Ethnomusicology Society for Music Theory The European Network for Theory & Analysis of Music === On-line journals === A list of open-access European journals in the domains of music theory and/or analysis is available on the website of the European Network for Theory & Analysis of Music. A more complete list of open-access journals in theory and analysis can be found on the website of the Société Belge d'Analyse Musicale (in French).
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The branches of science, also referred to as sciences, scientific fields or scientific disciplines, are commonly divided into three major groups: Formal sciences: the study of formal systems, such as those under the branches of logic and mathematics, which use an a priori, as opposed to empirical, methodology. They study abstract structures described by formal systems. Natural sciences: the study of natural phenomena (including cosmological, geological, physical, chemical, and biological factors of the universe). Natural science can be divided into two main branches: physical science and life science (or biology). Social sciences: the study of human behavior in its social and cultural aspects. Scientific knowledge must be grounded in observable phenomena and must be capable of being verified by other researchers working under the same conditions. Natural, social, and formal science make up the fundamental sciences, which form the basis of interdisciplinarity - and applied sciences such as engineering and medicine. Specialized scientific disciplines that exist in multiple categories may include parts of other scientific disciplines but often possess their own terminologies and expertises. == Formal sciences == The formal sciences are the branches of science that are concerned with formal systems, such as logic, mathematics, theoretical computer science, information theory, systems theory, decision theory, statistics. Unlike other branches, the formal sciences are not concerned with the validity of theories based on observations in the real world (empirical knowledge), but rather with the properties of formal systems based on definitions and rules. Hence there is disagreement on whether the formal sciences actually constitute as a science. Methods of the formal sciences are, however, essential to the construction and testing of scientific models dealing with observable reality, and major advances in formal sciences have often enabled major advances in the empirical sciences. === Logic === Logic (from Greek: λογική, logikḗ, 'possessed of reason, intellectual, dialectical, argumentative') is the systematic study of valid rules of inference, i.e. the relations that lead to the acceptance of one proposition (the conclusion) on the basis of a set of other propositions (premises). More broadly, logic is the analysis and appraisal of arguments. It has traditionally included the classification of arguments; the systematic exposition of the logical forms; the validity and soundness of deductive reasoning; the strength of inductive reasoning; the study of formal proofs and inference (including paradoxes and fallacies); and the study of syntax and semantics. Historically, logic has been studied in philosophy (since ancient times) and mathematics (since the mid-19th century). More recently, logic has been studied in cognitive science, which draws on computer science, linguistics, philosophy and psychology, among other disciplines. === Data science === === Information science === Information science is an academic field which is primarily concerned with analysis, collection, classification, manipulation, storage, retrieval, movement, dissemination, and protection of information. Practitioners within and outside the field study the application and the usage of knowledge in organizations in addition to the interaction between people, organizations, and any existing information systems with the aim of creating, replacing, improving, or understanding the information systems. === Mathematics === Mathematics, in the broadest sense, is just a synonym of formal science; but traditionally mathematics means more specifically the coalition of four areas: arithmetic, algebra, geometry, and analysis, which are, to some degree, the study of quantity, structure, space, and change respectively. === Statistics === Statistics is the study of the collection, organization, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments. A statistician is someone who is particularly well versed in the ways of thinking necessary for the successful application of statistical analysis. Such people have often gained this experience through working in any of a wide number of fields. There is also a discipline called mathematical statistics, which is concerned with the theoretical basis of the subject. The word statistics, when referring to the scientific discipline, is singular, as in "Statistics is an art." This should not be confused with the word statistic, referring to a quantity (such as mean or median) calculated from a set of data, whose plural is statistics ("this statistic seems wrong" or "these statistics are misleading"). === Systems theory === Systems theory is the transdisciplinary study of systems in general, to elucidate principles that can be applied to all types of systems in all fields of research. The term does not yet have a well-established, precise meaning, but systems theory can reasonably be considered a specialization of systems thinking and a generalization of systems science. The term originates from Bertalanffy's General System Theory (GST) and is used in later efforts in other fields, such as the action theory of Talcott Parsons and the sociological autopoiesis of Niklas Luhmann. In this context the word systems is used to refer specifically to self-regulating systems, i.e. that are self-correcting through feedback. Self-regulating systems are found in nature, including the physiological systems of the human body, in local and global ecosystems, and climate. === Decision theory === Decision theory (or the theory of choice not to be confused with choice theory) is the study of an agent's choices. Decision theory can be broken into two branches: normative decision theory, which analyzes the outcomes of decisions or determines the optimal decisions given constraints and assumptions, and descriptive decision theory, which analyzes how agents actually make the decisions they do. Decision theory is closely related to the field of game theory and is an interdisciplinary topic, studied by economists, statisticians, psychologists, biologists, political and other social scientists, philosophers, and computer. Empirical applications of this rich theory are usually done with the help of statistical and econometric methods. === Theoretical computer science === Theoretical computer science (TCS) is a subset of general computer science and mathematics that focuses on more mathematical topics of computing, and includes the theory of computation. It is difficult to circumscribe the theoretical areas precisely. The ACM's (Association for Computing Theory) Special Interest Group on Algorithms and Computation Theory (SIGACT) provides the following description: TCS covers a wide variety of topics including algorithms, data structures, computational complexity, parallel and distributed computation, probabilistic computation, quantum computation, automata theory, information theory, cryptography, program semantics and verification, machine learning, computational biology, computational economics, computational geometry, and computational number theory and algebra. Work in this field is often distinguished by its emphasis on mathematical technique and rigor. == Natural sciences == Natural science is a branch of science concerned with the description, prediction, and understanding of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeatability of findings are used to try to ensure the validity of scientific advances. Natural science can be divided into two main branches: life science and physical science. Life science is alternatively known as biology, and physical science is subdivided into branches: physics, chemistry, astronomy and Earth science. These branches of natural science may be further divided into more specialized branches (also known as fields). === Physical science === Physical science is an encompassing term for the branches of natural science that study non-living systems, in contrast to the life sciences. However, the term "physical" creates an unintended, somewhat arbitrary distinction, since many branches of physical science also study biological phenomena. There is a difference between physical science and physics. ==== Physics ==== Physics (from Ancient Greek: φύσις, romanized: physis, lit. 'nature') is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves. Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy. Over the last two millennia, physics was a part of natural philosophy along with chemistry, certain branches of mathematics, and biology, but during the Scientific Revolution in the 16th century, the natural sciences emerged as unique research programs in their own right. Certain research areas are interdisciplinary, such as biophysics and quantum chemistry, which means that the boundaries of physics are not rigidly defined. In the nineteenth and twentieth centuries physicalism emerged as a major unifying feature of the philosophy of science as physics provides fundamental explanations for every observed natural phenomenon. New ideas in physics often explain the fundamental mechanisms of other sciences, while opening to new research areas in mathematics and philosophy. ==== Chemistry ==== Chemistry (the etymology of the word has been much disputed) is the science of matter and the changes it undergoes. The science of matter is also addressed by physics, but while physics takes a more general and fundamental approach, chemistry is more specialized, being concerned by the composition, behavior (or reaction), structure, and properties of matter, as well as the changes it undergoes during chemical reactions. It is a physical science which studies various substances, atoms, molecules, and matter (especially carbon based). Example sub-disciplines of chemistry include: biochemistry, the study of substances found in biological organisms; physical chemistry, the study of chemical processes using physical concepts such as thermodynamics and quantum mechanics; and analytical chemistry, the analysis of material samples to gain an understanding of their chemical composition and structure. Many more specialized disciplines have emerged in recent years, e.g. neurochemistry the chemical study of the nervous system. ==== Earth science ==== Earth science (also known as geoscience, the geosciences or the Earth sciences) is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences. The formal discipline of Earth sciences may include the study of the atmosphere, hydrosphere, lithosphere, and biosphere, as well as the solid earth. Typically Earth scientists will use tools from physics, chemistry, biology, geography, chronology and mathematics to build a quantitative understanding of how the Earth system works, and how it evolved to its current state. ===== Geology ===== Geology (from the Ancient Greek γῆ, gē ("earth") and -λoγία, -logia, ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other Earth sciences, including hydrology and the atmospheric sciences, and so is treated as one major aspect of integrated Earth system science and planetary science. ===== Oceanography ===== Oceanography, or marine science, is the branch of Earth science that studies the ocean. It covers a wide range of topics, including marine organisms and ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the seafloor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it: biology, chemistry, geology, meteorology, and physics as well as geography. ===== Meteorology ===== Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 17th century. The 19th century saw breakthroughs occur after observing networks developed across several countries. After the development of the computer in the latter half of the 20th century, breakthroughs in weather forecasting were achieved. ==== Astronomy ==== Space science is the study of everything in outer space. This has sometimes been called astronomy, but recently astronomy has come to be regarded as a division of broader space science, which has grown to include other related fields, such as studying issues related to space travel and space exploration (including space medicine), space archaeology and science performed in outer space (see space research). === Biological science === Life science, also known as biology, is the natural science that studies life such as microorganisms, plants, and animals including human beings, – including their physical structure, chemical processes, molecular interactions, physiological mechanisms, development, and evolution. Despite the complexity of the science, certain unifying concepts consolidate it into a single, coherent field. Biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the creation and extinction of species. Living organisms are open systems that survive by transforming energy and decreasing their local entropy to maintain a stable and vital condition defined as homeostasis. ==== Biochemistry ==== Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. It is a sub-discipline of both biology and chemistry, and from a reductionist point of view it is fundamental in biology. Biochemistry is closely related to molecular biology, cell biology, genetics, and physiology. ==== Microbiology ==== Microbiology is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology and parasitology. ==== Botany ==== Botany, also called plant science(s), plant biology or phytology, is the science of plant life and a branch of biology. Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. ==== Zoology ==== Zoology () is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. The term is derived from Ancient Greek ζῷον, zōion, i.e. "animal" and λόγος, logos, i.e. "knowledge, study". Some branches of zoology include: anthrozoology, arachnology, archaeozoology, cetology, embryology, entomology, helminthology, herpetology, histology, ichthyology, malacology, mammalogy, morphology, nematology, ornithology, palaeozoology, pathology, primatology, protozoology, taxonomy, and zoogeography. ==== Ecology ==== Ecology (from Greek: οἶκος, "house", or "environment"; -λογία, "study of") is a branch of biology concerning interactions among organisms and their biophysical environment, which includes both biotic and abiotic components. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the flux of energy and matter through an environment. Organisms with specific life history traits sustain these processes. == Social sciences == Social science is the branch of science devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of society", established in the 19th century. In addition to sociology, it now encompasses a wide array of academic disciplines, including anthropology, archaeology, economics, education, history, human geography, law, linguistics, political science, and psychology. Positivist social scientists use methods resembling those of the natural sciences as tools for understanding society, and so define science in its stricter modern sense. Interpretivist social scientists, by contrast, may use social critique or symbolic interpretation rather than constructing empirically falsifiable theories. In modern academic practice, researchers are often eclectic, using multiple methodologies (for instance, by combining both quantitative and qualitative research). The term "social research" has also acquired a degree of autonomy as practitioners from various disciplines share in its aims and methods. == Applied sciences == Applied science is the use of existing scientific knowledge to achieve practical goals, like technology or inventions. Within natural science, disciplines that are basic science develop basic information to explain and perhaps predict phenomena in the natural world. Applied science is the use of scientific processes and knowledge as the means to achieve a particularly practical or useful result. This includes a broad range of applied science-related fields, including engineering and medicine. Applied science can also apply formal science, such as statistics and probability theory, as in epidemiology. Genetic epidemiology is an applied science applying both biological and statistical methods. == Relationships between the branches == The relationships between the branches of science are summarized by the table == Visualizations and metascience == Metascience refers to or includes a field of science that is about science itself. OpenAlex and Scholia can be used to visualize and explore scientific fields and research topics. == See also == Index of branches of science List of words ending in ology Outline of science Exact sciences Basic research Hard and soft science Branches of philosophy Philosophy of science Engineering physics Human science == Notes == == References == === Footnotes === === Works cited === == External links == Branches of Science, sciencemirror
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https://en.wikipedia.org/wiki/Branches_of_science
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Preregistration is the practice of registering the hypotheses, methods, or analyses of a scientific study before it is conducted. Clinical trial registration is similar, although it may not require the registration of a study's analysis protocol. Finally, registered reports include the peer review and in principle acceptance of a study protocol prior to data collection. Preregistration can have a number of different goals, including (a) facilitating and documenting research plans, (b) identifying and reducing questionable research practices and researcher biases, (c) distinguishing between confirmatory and exploratory analyses, (d) transparently evaluating the severity of hypothesis tests, and, in the case of Registered Reports, (e) facilitating results-blind peer review, and (f) reducing publication bias. A number of research practices such as p-hacking, publication bias, data dredging, inappropriate forms of post hoc analysis, and HARKing may increase the probability of incorrect claims. Although the idea of preregistration is old, the practice of preregistering studies has gained prominence to mitigate to some of the issues that are thought to underlie the replication crisis. == Types == === Standard preregistration === In the standard preregistration format, researchers prepare a research protocol document prior to conducting their research. Ideally, this document indicates the research hypotheses, sampling procedure, sample size, research design, testing conditions, stimuli, measures, data coding and aggregation method, criteria for data exclusions, and statistical analyses, including potential variations on those analyses. This preregistration document is then posted on a publicly available website such as the Open Science Framework or AsPredicted. The preregistered study is then conducted, and a report of the study and its results are submitted for publication together with access to the preregistration document. This preregistration approach allows peer reviewers and subsequent readers to cross-reference the preregistration document with the published research article in order to identify the presence of any undisclosed deviations of the preregistration. Deviations from the preregistration are possible and common in practice, but they should be transparently reported, and the consequences for the severity of the test should be evaluated. === Registered reports === The registered report format requires authors to submit a description of the study methods and analyses prior to data collection. Once the theoretical introduction, method, and analysis plan has been peer reviewed (Stage 1 peer review), publication of the findings is provisionally guaranteed (in principle acceptance). The proposed study is then performed, and the research report is submitted for Stage 2 peer review. Stage 2 peer review confirms that the actual research methods are consistent with the preregistered protocol, that quality thresholds are met (e.g., manipulation checks confirm the validity of the experimental manipulation), and that the conclusions follow from the data. Because studies are accepted for publication regardless of whether the results are statistically significant Registered Reports prevent publication bias. Meta-scientific research has shown that the percentage of non-significant results in Registered Reports is substantially higher than in standard publications. === Specialised preregistration === Preregistration can be used in relation to a variety of different research designs and methods, including: Quantitative research in psychology Qualitative research Preexisting data Single case designs Electroencephalogram research Experience sampling Exploratory research Animal Research == Clinical trial registration == Clinical trial registration is the practice of documenting clinical trials before they are performed in a clinical trials registry so as to combat publication bias and selective reporting. Registration of clinical trials is required in some countries and is increasingly being standardized. Some top medical journals will only publish the results of trials that have been pre-registered. A clinical trials registry is a platform which catalogs registered clinical trials. ClinicalTrials.gov, run by the United States National Library of Medicine (NLM) was the first online registry for clinical trials, and remains the largest and most widely used. In addition to combating bias, clinical trial registries serve to increase transparency and access to clinical trials for the public. Clinical trials registries are often searchable (e.g. by disease/indication, drug, location, etc.). Trials are registered by the pharmaceutical, biotech or medical device company (Sponsor) or by the hospital or foundation which is sponsoring the study, or by another organization, such as a contract research organization (CRO) which is running the study. There has been a push from governments and international organizations, especially since 2005, to make clinical trial information more widely available and to standardize registries and processes of registering. The World Health Organization is working toward "achieving consensus on both the minimal and the optimal operating standards for trial registration". === Creation and development === For many years, scientists and others have worried about reporting biases such that negative or null results from initiated clinical trials may be less likely to be published than positive results, thus skewing the literature and our understanding of how well interventions work. This worry has been international and written about for over 50 years. One of the proposals to address this potential bias was a comprehensive register of initiated clinical trials that would inform the public which trials had been started. Ethical issues were those that seemed to interest the public most, as trialists (including those with potential commercial gain) benefited from those who enrolled in trials, but were not required to “give back,” telling the public what they had learned. Those who were particularly concerned by the double standard were systematic reviewers, those who summarize what is known from clinical trials. If the literature is skewed, then the results of a systematic review are also likely to be skewed, possibly favoring the test intervention when in fact the accumulated data do not show this, if all data were made public. ClinicalTrials.gov was originally developed largely as a result of breast cancer consumer lobbying, which led to authorizing language in the FDA Modernization Act of 1997 (Food and Drug Administration Modernization Act of 1997. Pub L No. 105-115, §113 Stat 2296), but the law provided neither funding nor a mechanism of enforcement. In addition, the law required that ClinicalTrials.gov only include trials of serious and life-threatening diseases. Then, two events occurred in 2004 that increased public awareness of the problems of reporting bias. First, the then-New York State Attorney General Eliot Spitzer sued GlaxoSmithKline (GSK) because they had failed to reveal results from trials showing that certain antidepressants might be harmful. Shortly thereafter, the International Committee of Medical Journal Editors (ICMJE) announced that their journals would not publish reports of trials unless they had been registered. The ICMJE action was probably the most important motivator for trial registration, as investigators wanted to reserve the possibility that they could publish their results in prestigious journals, should they want to. In 2007, the Food and Drug Administration Amendments Act of 2007 (FDAAA) clarified the requirements for registration and also set penalties for non-compliance (Public Law 110-85. The Food and Drug Administration Amendments Act of 2007 [1]. === International participation === The International Committee of Medical Journal Editors (ICMJE) decided that from July 1, 2005 no trials will be considered for publication unless they are included on a clinical trials registry. The World Health Organization has begun the push for clinical trial registration with the initiation of the International Clinical Trials Registry Platform. There has also been action from the pharmaceutical industry, which released plans to make clinical trial data more transparent and publicly available. Released in October 2008, the revised Declaration of Helsinki, states that "Every clinical trial must be registered in a publicly accessible database before recruitment of the first subject." The World Health Organization maintains an international registry portal at http://apps.who.int/trialsearch/. WHO states that the international registry's mission is "to ensure that a complete view of research is accessible to all those involved in health care decision making. This will improve research transparency and will ultimately strengthen the validity and value of the scientific evidence base." Since 2007, the International Committee of Medical Journal Editors ICMJE accepts all primary registries in the WHO network in addition to clinicaltrials.gov. Clinical trial registration in other registries excluding ClinicalTrials.gov has increased irrespective of study designs since 2014. === Reporting compliance === Various studies have measured the extent to which various trials are in compliance with the reporting standards of their registry. === Overview of clinical trial registries === Worldwide, there is growing number of registries. A 2013 study identified the following top five registries (numbers updated as of August 2013): === Overview of preclinical study registries === Similar to clinical research, preregistration can help to improve transparency and quality of research data in preclinical research. In contrast to clinical research where preregistration is mandatory for vast parts it is still new in preclinical research. A large part of preclinical and basic biomedical research relies on animal experiments. The non-publication of results gained from animal experiments not only distorts the state of research by reinforcing the publication bias, it further represents an ethical issue. Preregistration is discussed as a measure that could counteract this problem. Following registries are suited for the preregistration of preclinical studies. == Journal support == Over 200 journals offer a registered reports option (Centre for Open Science, 2019), and the number of journals that are adopting registered reports is approximately doubling each year (Chambers et al., 2019). Psychological Science has encouraged the preregistration of studies and the reporting of effect sizes and confidence intervals. The editor-in-chief also noted that the editorial staff will be asking for replication of studies with surprising findings from examinations using small sample sizes before allowing the manuscripts to be published. Nature Human Behaviour has adopted the registered report format, as it “shift[s] the emphasis from the results of research to the questions that guide the research and the methods used to answer them”. European Journal of Personality defines this format: “In a registered report, authors create a study proposal that includes theoretical and empirical background, research questions/hypotheses, and pilot data (if available). Upon submission, this proposal will then be reviewed prior to data collection, and if accepted, the paper resulting from this peer-reviewed procedure will be published, regardless of the study outcomes.” Note that only a very small proportion of academic journals in psychology and neurosciences explicitly stated that they welcome submissions of replication studies in their aim and scope or instructions to authors. This phenomenon does not encourage the reporting or even attempt on replication studies. Overall, the number of participating journals is increasing, as indicated by the Center for Open Science, which maintains a list of journals encouraging the submission of registered reports. == Benefits == Several articles have outlined the rationale for preregistration (e.g., Lakens, 2019; Nosek et al., 2018; Wagenmakers et al., 2012). The primary goal of preregistration is to improve the transparency of reported hypothesis tests, which allows readers to evaluate the extent to which decisions during the data analysis were pre-planned (maintaining statistical error control) or data-driven (increasing the Type 1 or Type 2 error rate). Meta-scientific research has revealed additional benefits. Researchers indicate preregistering a study leads to a more carefully thought through research hypothesis, experimental design, and statistical analysis. In addition, preregistration has been shown to encourage better learning of Open Science concepts and students felt that they understood their dissertation and it improved the clarity of the manuscript writing, promoted rigour and were more likely to avoid questionable research practices. In addition, it becomes a tool that can supervisors can use to shape students to combat any questionable research practices. A 2024 study in the Journal of Political Economy: Microeconomics preregistration in economics journals found that preregistration did not reduce p-hacking and publication bias, unless the preregistration was accompanied by a preanalysis plan. == Criticisms == Proponents of preregistration have argued that it is "a method to increase the credibility of published results" (Nosek & Lakens, 2014), that it "makes your science better by increasing the credibility of your results" (Centre for Open Science), and that it "improves the interpretability and credibility of research findings" (Nosek et al., 2018, p. 2605). This argument assumes that non-preregistered exploratory analyses are less "credible" and/or "interpretable" than preregistered confirmatory analyses because they may involve "circular reasoning" in which post hoc hypotheses are based on the observed data (Nosek et al., 2018, p. 2600). However, critics have argued that preregistration is not necessary to identify circular reasoning during exploratory analyses (Rubin, 2020). Circular reasoning can be identified by analysing the reasoning per se without needing to know whether that reasoning was preregistered. Critics have also noted that the idea that preregistration improves research credibility may deter researchers from undertaking non-preregistered exploratory analyses (Coffman & Niederle, 2015; see also Collins et al., 2021, Study 1). In response, preregistration advocates have stressed that exploratory analyses are permitted in preregistered studies, and that the results of these analyses retain some value vis-a-vis hypothesis generation rather than hypothesis testing. Preregistration merely makes the distinction between confirmatory and exploratory research clearer (Nosek et al., 2018; Nosek & Lakens, 2014; Wagenmakers et al., 2012). Hence, although preregistraton is supposed to reduce researcher degrees of freedom during the data analysis stage, it is also supposed to be “a plan, not a prison” (Dehaven, 2017). However, critics counterargue that, if preregistration is only supposed to be a plan, and not a prison, then researchers should feel free to deviate from that plan and undertake exploratory analyses without fearing accusations of low research credibility due to circular reasoning and inappropriate research practices such as p-hacking and unreported multiple testing that leads to inflated familywise error rates (e.g., Navarro, 2020). Again, they have pointed out that preregistration is not necessary to address such concerns. For example, concerns about p-hacking and unreported multiple testing can be addressed if researchers engage in other open science practices, such as (a) open data and research materials and (b) robustness or multiverse analyses (Rubin, 2020; Steegen et al., 2016; for several other approaches, see Srivastava, 2018). Finally, and more fundamentally, critics have argued that the distinction between confirmatory and exploratory analyses is unclear and/or irrelevant (Devezer et al., 2020; Rubin, 2020; Szollosi & Donkin, 2019), and that concerns about inflated familywise error rates are unjustified when those error rates refer to abstract, atheoretical studywise hypotheses that are not being tested (Rubin, 2020, 2021; Szollosi et al., 2020). There are also concerns about the practical implementation of preregistration. Many preregistered protocols leave plenty of room for p-hacking (Bakker et al., 2020; Heirene et al., 2021; Ikeda et al., 2019; Singh et al., 2021; Van den Akker et al., 2023), and researchers rarely follow the exact research methods and analyses that they preregister (Abrams et al., 2020; Claesen et al., 2019; Heirene et al., 2021; Clayson et al., 2025; see also Boghdadly et al., 2018; Singh et al., 2021; Sun et al., 2019). For example, pre-registered studies are only of higher quality than non-pre-registered studies if the former has a power analysis and higher sample size than the latter but other than that they do not seem to prevent p-hacking and HARKing, as both the proportion of positive results and effect sizes are similar between preregistered and non-preregistered studies (Van den Akker et al., 2023). In addition, a survey of 27 preregistered studies found that researchers deviated from their preregistered plans in all cases (Claesen et al., 2019). The most frequent deviations were with regards to the planned sample size, exclusion criteria, and statistical model. Hence, what were intended as preregistered confirmatory tests ended up as unplanned exploratory tests. Again, preregistration advocates argue that deviations from preregistered plans are acceptable as long as they are reported transparently and justified. They also point out that even vague preregistrations help to reduce researcher degrees of freedom and make any residual flexibility transparent (Simmons et al., 2021, p. 180). A larger study of 92 EEG/ERP studies showed that only 60% of studies adhered to their preregistrations or disclosed all deviations. Notably, registered reports had the higher adherence rates (92%) than unreviewed preregistrations (60%). However, critics have argued that it is not useful to identify or justify deviations from preregistered plans when those plans do not reflect high quality theory and research practice. As Rubin (2020) explained, “we should be more interested in the rationale for the current method and analyses than in the rationale for historical changes that have led up to the current method and analyses” (pp. 378–379). In addition, pre-registering a study requires careful deliberation about the study's hypotheses, research design and statistical analyses. This depends on the use of pre-registration templates that provides detailed guidance on what to include and why (Bowman et al., 2016; Haven & Van Grootel, 2019; Van den Akker et al., 2021). Many pre-registration template stress the importance of a power analysis but not only stress the importance of why the methodology was used. Additionally to the concerns raised about its practical implementation in quantitative research, critics have also argued that preregistration is less applicable, or even unsuitable, for qualitative research. Pre-registration imposes rigidity, limiting researchers' ability to adapt to emerging data and evolving contexts, which are essential to capturing the richness of participants' lived experiences (Souza-Neto & Moyle, 2025). Additionally, it conflicts with the inductive and flexible nature of theory-building in qualitative research, constraining the exploratory approach that is central to this methodology (Souza-Neto & Moyle, 2025). Finally, some commentators have argued that, under some circumstances, preregistration may actually harm science by providing a false sense of credibility to research studies and analyses (Devezer et al., 2020; McPhetres, 2020; Pham & Oh, 2020; Szollosi et al., 2020). Consistent with this view, there is some evidence that researchers view registered reports as being more credible than standard reports on a range of dimensions (Soderberg et al., 2020; see also Field et al., 2020 for inconclusive evidence), although it is unclear whether this represents a "false" sense of credibility due to pre-existing positive community attitudes about preregistration or a genuine causal effect of registered reports on quality of research. == See also == AllTrials Clinical trial registration Metascience Open science == References == == External links == Preregistration resources from the Centre for Open Science Guidelines for creating registered reports by the Center for Open Science As Predicted
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https://en.wikipedia.org/wiki/Preregistration_(science)
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Library and information science (LIS) are two interconnected disciplines that deal with information management. This includes organization, access, collection, and regulation of information, both in physical and digital forms. Library science and information science are two original disciplines; however, they are within the same field of study. Library science is applied information science. Library science is both an application and a subfield of information science. Due to the strong connection, sometimes the two terms are used synonymously. == Definition == Library science (previously termed library studies and library economy) is an interdisciplinary or multidisciplinary field that applies the practices, perspectives, and tools of management, information technology, education, and other areas to libraries; the collection, organization, preservation, and dissemination of information resources; and the political economy of information. Martin Schrettinger, a Bavarian librarian, coined the discipline within his work (1808–1828) Versuch eines vollständigen Lehrbuchs der Bibliothek-Wissenschaft oder Anleitung zur vollkommenen Geschäftsführung eines Bibliothekars. Rather than classifying information based on nature-oriented elements, as was previously done in his Bavarian library, Schrettinger organized books in alphabetical order. The first American school for library science was founded by Melvil Dewey at Columbia University in 1887. Historically, library science has also included archival science. This includes: how information resources are organized to serve the needs of selected user groups; how people interact with classification systems and technology; how information is acquired, evaluated and applied by people in and outside libraries as well as cross-culturally; how people are trained and educated for careers in libraries; the ethics that guide library service and organization; the legal status of libraries and information resources; and the applied science of computer technology used in documentation and records management. LIS should not be confused with information theory, the mathematical study of the concept of information. Library philosophy has been contrasted with library science as the study of the aims and justifications of librarianship as opposed to the development and refinement of techniques. == Education and training == Academic courses in library science include collection management, information systems and technology, research methods, user studies, information literacy, cataloging and classification, preservation, reference, statistics and management. Library science is constantly evolving, incorporating new topics like database management, information architecture and information management, among others. With the mounting acceptance of Wikipedia as a valued and reliable reference source, many libraries, museums, and archives have introduced the role of Wikipedian in residence. As a result, some universities are including coursework relating to Wikipedia and Knowledge Management in their MLIS programs. Becoming a library staff member does not always need a degree, and in some contexts the difference between being a library staff member and a librarian is the level of education. Most professional library jobs require a professional degree in library science or equivalent. In the United States and Canada the certification usually comes from a master's degree granted by an ALA-accredited institution. In Australia, a number of institutions offer degrees accepted by the ALIA (Australian Library and Information Association). Global standards of accreditation or certification in librarianship have yet to be developed. === United States and Canada === The Master of Library and Information Science (MLIS) is the master's degree that is required for most professional librarian positions in the United States and Canada. The MLIS was created after the older Master of Library Science (MLS) was reformed to reflect the information science and technology needs of the field. According to the American Library Association (ALA), "ALA-accredited degrees have [had] various names such as Master of Arts, Master of Librarianship, Master of Library and Information Studies, or Master of Science. The degree name is determined by the program. The [ALA] Committee for Accreditation evaluates programs based on their adherence to the Standards for Accreditation of Master's Programs in Library and Information Studies, not based on the name of the degree." == Types of librarianship == === Public === The study of librarianship for public libraries covers issues such as cataloging; collection development for a diverse community; information literacy; readers' advisory; community standards; public services-focused librarianship via community-centered programming; serving a diverse community of adults, children, and teens; intellectual freedom; censorship; and legal and budgeting issues. The public library as a commons or public sphere based on the work of Jürgen Habermas has become a central metaphor in the 21st century. In the United States there are four different types of public libraries: association libraries, municipal public libraries, school district libraries, and special district public libraries. Each receives funding through different sources, each is established by a different set of voters, and not all are subject to municipal civil service governance. === School === The study of school librarianship covers library services for children in Nursery, primary through secondary school. In some regions, the local government may have stricter standards for the education and certification of school librarians (who are sometimes considered a special case of teacher), than for other librarians, and the educational program will include those local criteria. School librarianship may also include issues of intellectual freedom, pedagogy, information literacy, and how to build a cooperative curriculum with the teaching staff. === Academic === The study of academic librarianship covers library services for colleges and universities. Issues of special importance to the field may include copyright; technology; digital libraries and digital repositories; academic freedom; open access to scholarly works; and specialized knowledge of subject areas important to the institution and the relevant reference works. Librarians often divide focus individually as liaisons on particular schools within a college or university. Academic librarians may be subject specific librarians. Some academic librarians are considered faculty, and hold similar academic ranks to those of professors, while others are not. In either case, the minimal qualification is a Master of Arts in Library Studies or a Master of Arts in Library Science. Some academic libraries may only require a master's degree in a specific academic field or a related field, such as educational technology. === Archival === The study of archives includes the training of archivists, librarians specially trained to maintain and build archives of records intended for historical preservation. Special issues include physical preservation, conservation, and restoration of materials and mass deacidification; specialist catalogs; solo work; access; and appraisal. Many archivists are also trained historians specializing in the period covered by the archive. There have been attempts to revive the concept of documentation and to speak of Library, information and documentation studies (or science). The archival mission includes three major goals: To identify papers and records with enduring value, preserve the identified papers, and make the papers available to others. While libraries receive items individually, archival items will usually become part of the archive's collection as a cohesive group. Major difference in collections is that library collections typically comprise published items (books, magazines, etc.), while archival collections are usually unpublished works (letters, diaries, etc.). Library collections are created by many individuals, as each author and illustrator create their own publication; in contrast, an archive usually collects the records of one person, family, institution, or organization, so the archival items will have fewer sources of authors. Behavior in an archive differs from behavior in other libraries. In most libraries, items are openly available to the public. Archival items almost never circulate, and someone interested in viewing documents must request them of the archivist and may only be able view them in a closed reading room. === Special === Special libraries are libraries established to meet the highly specialized requirements of professional or business groups. A library is special depending on whether it covers a specialized collection, a special subject, or a particular group of users, or even the type of parent organization, such as medical libraries or law libraries. The issues at these libraries are specific to their industries but may include solo work, corporate financing, specialized collection development, and extensive self-promotion to potential patrons. Special librarians have their own professional organization, the Special Libraries Association (SLA). Some special libraries, such as the CIA Library, may contain classified works. It is a resource to employees of the Central Intelligence Agency, containing over 125,000 written materials, subscribes to around 1,700 periodicals, and had collections in three areas: Historical Intelligence, Circulating, and Reference. In February 1997, three librarians working at the institution spoke to Information Outlook, a publication of the SLA, revealing that the library had been created in 1947, the importance of the library in disseminating information to employees, even with a small staff, and how the library organizes its materials. === Preservation === Preservation librarians most often work in academic libraries. Their focus is on the management of preservation activities that seek to maintain access to content within books, manuscripts, archival materials, and other library resources. Examples of activities managed by preservation librarians include binding, conservation, digital and analog reformatting, digital preservation, and environmental monitoring. == History == Libraries have existed for many centuries but library science is a more recent phenomenon, as early libraries were managed primarily by academics. === 17th and 18th century === The earliest text on "library operations", Advice on Establishing a Library was published in 1627 by French librarian and scholar Gabriel Naudé. Naudé wrote on many subjects including politics, religion, history, and the supernatural. He put into practice all the ideas put forth in Advice when given the opportunity to build and maintain the library of Cardinal Jules Mazarin. During the 'golden age of libraries' in the 17th century, publishers and sellers seeking to take advantage of the burgeoning book trade developed descriptive catalogs of their wares for distribution – a practice was adopted and further extrapolated by many libraries of the time to cover areas like philosophy, sciences, linguistics, and medicine In 1726 Gottfried Wilhelm Leibniz wrote Idea of Arranging a Narrower Library. === 19th century === Martin Schrettinger wrote the second textbook (the first in Germany) on the subject from 1808 to 1829. Some of the main tools used by LIS to provide access to the resources originated in 19th century to make information accessible by recording, identifying, and providing bibliographic control of printed knowledge. The origin for some of these tools were even earlier. Thomas Jefferson, whose library at Monticello consisted of thousands of books, devised a classification system inspired by the Baconian method, which grouped books more or less by subject rather than alphabetically, as it was previously done. The Jefferson collection provided the start of what became the Library of Congress. The first American school of librarianship opened at Columbia University under the leadership of Melvil Dewey, noted for his 1876 decimal classification, on January 5, 1887, as the School of Library Economy. The term library economy was common in the U.S. until 1942, with the term, library science, predominant through much of the 20th century. === 20th century === In the English-speaking world the term "library science" seems to have been used for the first time in India in the 1916 book Punjab Library Primer, written by Asa Don Dickinson and published by the University of Punjab, Lahore, Pakistan. This university was the first in Asia to begin teaching "library science". The Punjab Library Primer was the first textbook on library science published in English anywhere in the world. The first textbook in the United States was the Manual of Library Economy by James Duff Brown, published in 1903. Later, the term was used in the title of S. R. Ranganathan's The Five Laws of Library Science, published in 1931, which contains Ranganathan's titular theory. Ranganathan is also credited with the development of the first major analytical-synthetic classification system, the colon classification. In the United States, Lee Pierce Butler published his 1933 book An Introduction to Library Science (University of Chicago Press), where he advocated for research using quantitative methods and ideas in the social sciences with the aim of using librarianship to address society's information needs. He was one of the first faculty at the University of Chicago Graduate Library School, which changed the structure and focus of education for librarianship in the twentieth century. This research agenda went against the more procedure-based approach of the "library economy", which was mostly confined to practical problems in the administration of libraries. In 1923, Charles C. Williamson, who was appointed by the Carnegie Corporation, published an assessment of library science education entitled "The Williamson Report", which designated that universities should provide library science training. This report had a significant impact on library science training and education. Library research and practical work, in the area of information science, have remained largely distinct both in training and in research interests. William Stetson Merrill's A Code for Classifiers, released in several editions from 1914 to 1939, is an example of a more pragmatic approach, where arguments stemming from in-depth knowledge about each field of study are employed to recommend a system of classification. While Ranganathan's approach was philosophical, it was also tied more to the day-to-day business of running a library. A reworking of Ranganathan's laws was published in 1995 which removes the constant references to books. Michael Gorman's Our Enduring Values: Librarianship in the 21st Century features the eight principles necessary by library professionals and incorporates knowledge and information in all their forms, allowing for digital information to be considered. ==== From library science to LIS ==== By the late 1960s, mainly due to the meteoric rise of human computing power and the new academic disciplines formed therefrom, academic institutions began to add the term "information science" to their names. The first school to do this was at the University of Pittsburgh in 1964. More schools followed during the 1970s and 1980s. By the 1990s almost all library schools in the US had added information science to their names. Although there are exceptions, similar developments have taken place in other parts of the world. In India, the Dept of Library Science, University of Madras (southern state of TamiilNadu, India) became the Dept. of Library and Information Science in 1976. In Denmark, for example, the "Royal School of Librarianship" changed its English name to The Royal School of Library and Information Science in 1997. === 21st century === The digital age has transformed how information is accessed and retrieved. "The library is now a part of a complex and dynamic educational, recreational, and informational infrastructure." Mobile devices and applications with wireless networking, high-speed computers and networks, and the computing cloud have deeply impacted and developed information science and information services. The evolution of the library sciences maintains its mission of access equity and community space, as well as the new means for information retrieval called information literacy skills. All catalogs, databases, and a growing number of books are available on the Internet. In addition, the expanding free access to open access journals and sources such as Wikipedia has fundamentally impacted how information is accessed. Information literacy is the ability to "determine the extent of information needed, access the needed information effectively and efficiently, evaluate information and its sources critically, incorporate selected information into one's knowledge base, use information effectively to accomplish a specific purpose, and understand the economic, legal, and social issues surrounding the use of information, and access and use information ethically and legally." In the early 2000s, dLIST, Digital Library for Information Sciences and Technology was established. It was the first open access archive for the multidisciplinary 'library and information sciences' building a global scholarly communication consortium and the LIS Commons in order to increase the visibility of research literature, bridge the divide between practice, teaching, and research communities, and improve visibility, uncitedness, and integrate scholarly work in the critical information infrastructures of archives, libraries, and museums. Social justice, an important ethical value in librarianship and in the 21st century has become an important research area, if not subdiscipline of LIS. == Journals == See also List of Library and Information Science Journals Category:Library science journals Journal Citation Reports for listing according to Impact factor) Some core journals in LIS are: Annual Review of Information Science and Technology (ARIST) (1966–2011) El Profesional de la Información (EPI) (1992–) (Formerly Information World en Español) Information Processing and Management Information Research: An International Electronic Journal (IR) (1995–) Italian Journal of Library and Information Studies (JLIS.it) Journal of Documentation (JDoc) (1945–) Journal of Information Science (JIS) (1979–) Journal of the Association for Information Science and Technology (Formerly Journal of the American Society for Information Science and Technology) (JASIST) (1950–) Knowledge Organization (journal) Library Literature and Information Science Retrospective Library Trends (1952–) Scientometrics (journal) (1978–) The Library Quarterly (LQ) (1931–) Grandhalaya Sarvaswam (1915–) Important bibliographical databases in LIS are, among others, Social Sciences Citation Index and Library and Information Science Abstracts == Conferences == This is a list of some of the major conferences in the field. Annual meetings of the American Library Association. Annual meeting of the American Society for Information Science and Technology Annual meeting of the Association for Library and Information Science Education Conceptions of Library and Information Science i-Schools' iConferences The International Federation of Library Associations and Institutions (IFLA): World Library and Information Congress African Library and Information Associations and Institutions (AfLIA) Conference == Subfields == Information science grew out of documentation science and therefore has a tradition for considering scientific and scholarly communication, bibliographic databases, subject knowledge and terminology etc. An advertisement for a full Professor in information science at the Royal School of Library and Information Science, spring 2011, provides one view of which sub-disciplines are well-established: "The research and teaching/supervision must be within some (and at least one) of these well-established information science areas A curriculum study by Kajberg & Lørring in 2005 reported a "degree of overlap of the ten curricular themes with subject areas in the current curricula of responding LIS schools". Information seeking and Information retrieval 100% Library management and promotion 96% Knowledge management 86% Knowledge organization 82% Information literacy and learning 76% Library and society in a historical perspective (Library history) 66% The Information society: Barriers to the free access to information 64% Cultural heritage and digitisation of the cultural heritage (Digital preservation) 62% The library in the multi-cultural information society: International and intercultural communication 42% Mediation of culture in a special European context 26% " There is often an overlap between these subfields of LIS and other fields of study. Most information retrieval research, for example, belongs to computer science. Knowledge management is considered a subfield of management or organizational studies. === Metadata === Pre-Internet classification systems and cataloging systems were mainly concerned with two objectives: To provide rich bibliographic descriptions and relations between information objects, and To facilitate sharing of this bibliographic information across library boundaries. The development of the Internet and the information explosion that followed found many communities needing mechanisms for the description, authentication and management of their information. These communities developed taxonomies and controlled vocabularies to describe their knowledge, as well as unique information architectures to communicate these classifications and libraries found themselves as liaison or translator between these metadata systems. The concerns of cataloging in the Internet era have gone beyond simple bibliographic descriptions and the need for descriptive information about the ownership and copyright of a digital product – a publishing concern – and description for the different formats and accessibility features of a resource – a sociological concern – show the continued development and cross discipline necessity of resource description. In the 21st century, the usage of open data, open source and open protocols like OAI-PMH has allowed thousands of libraries and institutions to collaborate on the production of global metadata services previously offered only by increasingly expensive commercial proprietary products. Tools like BASE and Unpaywall automate the search of an academic paper across thousands of repositories by libraries and research institutions. === Knowledge organization === Library science is very closely related to issues of knowledge organization; however, the latter is a broader term that covers how knowledge is represented and stored (computer science/linguistics), how it might be automatically processed (artificial intelligence), and how it is organized outside the library in global systems such as the internet. In addition, library science typically refers to a specific community engaged in managing holdings as they are found in university and government libraries, while knowledge organization, in general, refers to this and also to other communities (such as publishers) and other systems (such as the Internet). The library system is thus one socio-technical structure for knowledge organization. The terms 'information organization' and 'knowledge organization' are often used synonymously.: 106 The fundamentals of their study - particularly theory relating to indexing and classification - and many of the main tools used by the disciplines in modern times to provide access to digital resources such as abstracting, metadata, resource description, systematic and alphabetic subject description, and terminology, originated in the 19th century and were developed, in part, to assist in making humanity's intellectual output accessible by recording, identifying, and providing bibliographic control of printed knowledge.: 105 Information has been published that analyses the relations between the philosophy of information (PI), library and information science (LIS), and social epistemology (SE). === Ethics === Practicing library professionals and members of the American Library Association recognize and abide by the ALA Code of Ethics. According to the American Library Association, "In a political system grounded in an informed citizenry, we are members of a profession explicitly committed to intellectual freedom and freedom of access to information. We have a special obligation to ensure the free flow of information and ideas to present and future generations." The ALA Code of Ethics was adopted in the winter of 1939, and updated on June 29, 2021. == See also == == Notes == == References == == Further reading == Åström, Fredrik (September 5, 2008). "Formalizing a discipline: The institutionalization of library and information science research in the Nordic countries". Journal of Documentation. 64 (5): 721–737. doi:10.1108/00220410810899736. Bawden, David; Robinson, Lyn (August 20, 2012). Introduction to Information Science. American Library Association. ISBN 978-1555708610. Hjørland, Birger (2000). "Library and information science: practice, theory, and philosophical basis". Information Processing & Management. 36 (3): 501–531. doi:10.1016/S0306-4573(99)00038-2. Järvelin, Kalervo; Vakkari, Pertti (January 1993). "The evolution of library and information science 1965–1985: A content analysis of journal articles". Information Processing & Management. 29 (1): 129–144. doi:10.1016/0306-4573(93)90028-C. McNicol, Sarah (March 2003). "LIS: the interdisciplinary research landscape". Journal of Librarianship and Information Science. 35 (1): 23–30. doi:10.1177/096100060303500103. S2CID 220912521. Dick, Archie L. (1995). "Library and Information Science as a Social Science: Neutral and Normative Conceptions". The Library Quarterly: Information, Community, Policy. 65 (2): 216–235. doi:10.1086/602777. JSTOR 4309022. S2CID 142825177. Foundational Books in Library Services.1976-2024. LHRT News & Notes. October, 2024. International Journal of Library Science (ISSN 0975-7546) Lafontaine, Gerard S. (1958). Dictionary of Terms Used in the Paper, Printing, and Allied Industries. Toronto: H. Smith Paper Mills. 110 p. The Oxford Guide to Library Research (2005) – ISBN 0195189981 Taşkın, Zehra (2021). "Forecasting the future of library and information science and its sub-fields". Scientometrics. 126 (2): 1527–1551. doi:10.1007/s11192-020-03800-2. PMC 7745590. PMID 33353991. Thompson, Elizabeth H. (1943). A.L.A. Glossary of Library Terms, with a Selection of Terms in Related Fields, prepared under the direction of the Committee on Library Terminology of the American Library Association. Chicago, Ill.: American Library Association. viii, 189 p. ISBN 978-0838900000 V-LIB 1.2 (2008 Vartavan Library Classification, over 700 fields of sciences & arts classified according to a relational philosophy, currently sold under license in the UK by Rosecastle Ltd. (see Vartavan-Frame) == External links == Media related to Library and information science at Wikimedia Commons LISNews.org – librarian and information science news LISWire.com – librarian and information science wire
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Network science is an academic field which studies complex networks such as telecommunication networks, computer networks, biological networks, cognitive and semantic networks, and social networks, considering distinct elements or actors represented by nodes (or vertices) and the connections between the elements or actors as links (or edges). The field draws on theories and methods including graph theory from mathematics, statistical mechanics from physics, data mining and information visualization from computer science, inferential modeling from statistics, and social structure from sociology. The United States National Research Council defines network science as "the study of network representations of physical, biological, and social phenomena leading to predictive models of these phenomena." == Background and history == The study of networks has emerged in diverse disciplines as a means of analyzing complex relational data. The earliest known paper in this field is the famous Seven Bridges of Königsberg written by Leonhard Euler in 1736. Euler's mathematical description of vertices and edges was the foundation of graph theory, a branch of mathematics that studies the properties of pairwise relations in a network structure. The field of graph theory continued to develop and found applications in chemistry (Sylvester, 1878). Dénes Kőnig, a Hungarian mathematician and professor, wrote the first book in Graph Theory, entitled "Theory of finite and infinite graphs", in 1936. In the 1930s Jacob Moreno, a psychologist in the Gestalt tradition, arrived in the United States. He developed the sociogram and presented it to the public in April 1933 at a convention of medical scholars. Moreno claimed that "before the advent of sociometry no one knew what the interpersonal structure of a group 'precisely' looked like". The sociogram was a representation of the social structure of a group of elementary school students. The boys were friends of boys and the girls were friends of girls with the exception of one boy who said he liked a single girl. The feeling was not reciprocated. This network representation of social structure was found so intriguing that it was printed in The New York Times. The sociogram has found many applications and has grown into the field of social network analysis. Probabilistic theory in network science developed as an offshoot of graph theory with Paul Erdős and Alfréd Rényi's eight famous papers on random graphs. For social networks the exponential random graph model or p* is a notational framework used to represent the probability space of a tie occurring in a social network. An alternate approach to network probability structures is the network probability matrix, which models the probability of edges occurring in a network, based on the historic presence or absence of the edge in a sample of networks. Interest in networks exploded around 2000, following new discoveries that offered novel mathematical framework to describe different network topologies, leading to the term 'network science'. Albert-László Barabási and Reka Albert discovered the scale-free networks nature of many real networks, from the WWW to the cell. The scale-free property captures the fact that in real network hubs coexist with many small degree vertices, and the authors offered a dynamical model to explain the origin of this scale-free state. Duncan Watts and Steven Strogatz reconciled empirical data on networks with mathematical representation, describing the small-world network. == Network Classification == === Deterministic Network === The definition of deterministic network is defined compared with the definition of probabilistic network. In un-weighted deterministic networks, edges either exist or not, usually we use 0 to represent non-existence of an edge while 1 to represent existence of an edge. In weighted deterministic networks, the edge value represents the weight of each edge, for example, the strength level. === Probabilistic Network === In probabilistic networks, values behind each edge represent the likelihood of the existence of each edge. For example, if one edge has a value equals to 0.9, we say the existence probability of this edge is 0.9. == Network properties == Often, networks have certain attributes that can be calculated to analyze the properties & characteristics of the network. The behavior of these network properties often define network models and can be used to analyze how certain models contrast to each other. Many of the definitions for other terms used in network science can be found in Glossary of graph theory. === Size === The size of a network can refer to the number of nodes N {\displaystyle N} or, less commonly, the number of edges E {\displaystyle E} which (for connected graphs with no multi-edges) can range from N − 1 {\displaystyle N-1} (a tree) to E max {\displaystyle E_{\max }} (a complete graph). In the case of a simple graph (a network in which at most one (undirected) edge exists between each pair of vertices, and in which no vertices connect to themselves), we have E max = ( N 2 ) = N ( N − 1 ) / 2 {\displaystyle E_{\max }={\tbinom {N}{2}}=N(N-1)/2} ; for directed graphs (with no self-connected nodes), E max = N ( N − 1 ) {\displaystyle E_{\max }=N(N-1)} ; for directed graphs with self-connections allowed, E max = N 2 {\displaystyle E_{\max }=N^{2}} . In the circumstance of a graph within which multiple edges may exist between a pair of vertices, E max = ∞ {\displaystyle E_{\max }=\infty } . === Density === The density D {\displaystyle D} of a network is defined as a normalized ratio between 0 and 1 of the number of edges E {\displaystyle E} to the number of possible edges in a network with N {\displaystyle N} nodes. Network density is a measure of the percentage of "optional" edges that exist in the network and can be computed as D = E − E m i n E m a x − E m i n {\displaystyle D={\frac {E-E_{\mathrm {min} }}{E_{\mathrm {max} }-E_{\mathrm {min} }}}} where E m i n {\displaystyle E_{\mathrm {min} }} and E m a x {\displaystyle E_{\mathrm {max} }} are the minimum and maximum number of edges in a connected network with N {\displaystyle N} nodes, respectively. In the case of simple graphs, E m a x {\displaystyle E_{\mathrm {max} }} is given by the binomial coefficient ( N 2 ) {\displaystyle {\tbinom {N}{2}}} and E m i n = N − 1 {\displaystyle E_{\mathrm {min} }=N-1} , giving density D = E − ( N − 1 ) E m a x − ( N − 1 ) = 2 ( E − N + 1 ) N ( N − 3 ) + 2 {\displaystyle D={\frac {E-(N-1)}{E_{\mathrm {max} }-(N-1)}}={\frac {2(E-N+1)}{N(N-3)+2}}} . Another possible equation is D = T − 2 N + 2 N ( N − 3 ) + 2 , {\displaystyle D={\frac {T-2N+2}{N(N-3)+2}},} whereas the ties T {\displaystyle T} are unidirectional (Wasserman & Faust 1994). This gives a better overview over the network density, because unidirectional relationships can be measured. === Planar network density === The density D {\displaystyle D} of a network, where there is no intersection between edges, is defined as a ratio of the number of edges E {\displaystyle E} to the number of possible edges in a network with N {\displaystyle N} nodes, given by a graph with no intersecting edges ( E max = 3 N − 6 ) {\displaystyle (E_{\max }=3N-6)} , giving D = E − N + 1 2 N − 5 . {\displaystyle D={\frac {E-N+1}{2N-5}}.} === Average degree === The degree k {\displaystyle k} of a node is the number of edges connected to it. Closely related to the density of a network is the average degree, ⟨ k ⟩ = 2 E N {\displaystyle \langle k\rangle ={\tfrac {2E}{N}}} (or, in the case of directed graphs, ⟨ k ⟩ = E N {\displaystyle \langle k\rangle ={\tfrac {E}{N}}} , the former factor of 2 arising from each edge in an undirected graph contributing to the degree of two distinct vertices). In the ER random graph model ( G ( N , p ) {\displaystyle G(N,p)} ) we can compute the expected value of ⟨ k ⟩ {\displaystyle \langle k\rangle } (equal to the expected value of k {\displaystyle k} of an arbitrary vertex): a random vertex has N − 1 {\displaystyle N-1} other vertices in the network available, and with probability p {\displaystyle p} , connects to each. Thus, E [ ⟨ k ⟩ ] = E [ k ] = p ( N − 1 ) {\displaystyle \mathbb {E} [\langle k\rangle ]=\mathbb {E} [k]=p(N-1)} . Degree distribution The degree distribution P ( k ) {\displaystyle P(k)} is a fundamental property of both real networks, such as the Internet and social networks, and of theoretical models. The degree distribution P(k) of a network is defined to be the fraction of nodes in the network with degree k. The simplest network model, for example, the (Erdős–Rényi model) random graph, in which each of n nodes is independently connected (or not) with probability p (or 1 − p), has a binomial distribution of degrees k (or Poisson in the limit of large n). Most real networks, from the WWW to the protein interaction networks, however, have a degree distribution that are highly right-skewed, meaning that a large majority of nodes have low degree but a small number, known as "hubs", have high degree. For such scale-free networks the degree distribution approximately follows a power law: P ( k ) ∼ k − γ {\displaystyle P(k)\sim k^{-\gamma }} , where γ is the degree exponent, and is a constant. Such scale-free networks have unexpected structural and dynamical properties, rooted in the diverging second moment of the degree distribution. === Average shortest path length (or characteristic path length) === The average shortest path length is calculated by finding the shortest path between all pairs of nodes, and taking the average over all paths of the length thereof (the length being the number of intermediate edges contained in the path, i.e., the distance d u , v {\displaystyle d_{u,v}} between the two vertices u , v {\displaystyle u,v} within the graph). This shows us, on average, the number of steps it takes to get from one member of the network to another. The behavior of the expected average shortest path length (that is, the ensemble average of the average shortest path length) as a function of the number of vertices N {\displaystyle N} of a random network model defines whether that model exhibits the small-world effect; if it scales as O ( ln N ) {\displaystyle O(\ln N)} , the model generates small-world nets. For faster-than-logarithmic growth, the model does not produce small worlds. The special case of O ( ln ln N ) {\displaystyle O(\ln \ln N)} is known as ultra-small world effect. === Diameter of a network === As another means of measuring network graphs, we can define the diameter of a network as the longest of all the calculated shortest paths in a network. It is the shortest distance between the two most distant nodes in the network. In other words, once the shortest path length from every node to all other nodes is calculated, the diameter is the longest of all the calculated path lengths. The diameter is representative of the linear size of a network. If node A-B-C-D are connected, going from A->D this would be the diameter of 3 (3-hops, 3-links). === Clustering coefficient === The clustering coefficient is a measure of an "all-my-friends-know-each-other" property. This is sometimes described as the friends of my friends are my friends. More precisely, the clustering coefficient of a node is the ratio of existing links connecting a node's neighbors to each other to the maximum possible number of such links. The clustering coefficient for the entire network is the average of the clustering coefficients of all the nodes. A high clustering coefficient for a network is another indication of a small world. The clustering coefficient of the i {\displaystyle i} 'th node is C i = 2 e i k i ( k i − 1 ) , {\displaystyle C_{i}={2e_{i} \over k_{i}{(k_{i}-1)}}\,,} where k i {\displaystyle k_{i}} is the number of neighbours of the i {\displaystyle i} 'th node, and e i {\displaystyle e_{i}} is the number of connections between these neighbours. The maximum possible number of connections between neighbors is, then, ( k 2 ) = k ( k − 1 ) 2 . {\displaystyle {\binom {k}{2}}={{k(k-1)} \over 2}\,.} From a probabilistic standpoint, the expected local clustering coefficient is the likelihood of a link existing between two arbitrary neighbors of the same node. === Connectedness === The way in which a network is connected plays a large part into how networks are analyzed and interpreted. Networks are classified in four different categories: Clique/Complete Graph: a completely connected network, where all nodes are connected to every other node. These networks are symmetric in that all nodes have in-links and out-links from all others. Giant Component: A single connected component which contains most of the nodes in the network. Weakly Connected Component: A collection of nodes in which there exists a path from any node to any other, ignoring directionality of the edges. Strongly Connected Component: A collection of nodes in which there exists a directed path from any node to any other. === Node centrality === Centrality indices produce rankings which seek to identify the most important nodes in a network model. Different centrality indices encode different contexts for the word "importance." The betweenness centrality, for example, considers a node highly important if it form bridges between many other nodes. The eigenvalue centrality, in contrast, considers a node highly important if many other highly important nodes link to it. Hundreds of such measures have been proposed in the literature. Centrality indices are only accurate for identifying the most important nodes. The measures are seldom, if ever, meaningful for the remainder of network nodes. Also, their indications are only accurate within their assumed context for importance, and tend to "get it wrong" for other contexts. For example, imagine two separate communities whose only link is an edge between the most junior member of each community. Since any transfer from one community to the other must go over this link, the two junior members will have high betweenness centrality. But, since they are junior, (presumably) they have few connections to the "important" nodes in their community, meaning their eigenvalue centrality would be quite low. === Node influence === Limitations to centrality measures have led to the development of more general measures. Two examples are the accessibility, which uses the diversity of random walks to measure how accessible the rest of the network is from a given start node, and the expected force, derived from the expected value of the force of infection generated by a node. Both of these measures can be meaningfully computed from the structure of the network alone. === Community structure === Nodes in a network may be partitioned into groups representing communities. Depending on the context, communities may be distinct or overlapping. Typically, nodes in such communities will be strongly connected to other nodes in the same community, but weakly connected to nodes outside the community. In the absence of a ground truth describing the community structure of a specific network, several algorithms have been developed to infer possible community structures using either supervised of unsupervised clustering methods. == Network models == Network models serve as a foundation to understanding interactions within empirical complex networks. Various random graph generation models produce network structures that may be used in comparison to real-world complex networks. === Erdős–Rényi random graph model === The Erdős–Rényi model, named for Paul Erdős and Alfréd Rényi, is used for generating random graphs in which edges are set between nodes with equal probabilities. It can be used in the probabilistic method to prove the existence of graphs satisfying various properties, or to provide a rigorous definition of what it means for a property to hold for almost all graphs. To generate an Erdős–Rényi model G ( n , p ) {\displaystyle G(n,p)} two parameters must be specified: the total number of nodes n and the probability p that a random pair of nodes has an edge. Because the model is generated without bias to particular nodes, the degree distribution is binomial: for a randomly chosen vertex v {\displaystyle v} , P ( deg ( v ) = k ) = ( n − 1 k ) p k ( 1 − p ) n − 1 − k . {\displaystyle P(\deg(v)=k)={n-1 \choose k}p^{k}(1-p)^{n-1-k}.} In this model the clustering coefficient is 0 a.s. The behavior of G ( n , p ) {\displaystyle G(n,p)} can be broken into three regions. Subcritical n p < 1 {\displaystyle np<1} : All components are simple and very small, the largest component has size | C 1 | = O ( log n ) {\displaystyle |C_{1}|=O(\log n)} ; Critical n p = 1 {\displaystyle np=1} : | C 1 | = O ( n 2 3 ) {\displaystyle |C_{1}|=O(n^{\frac {2}{3}})} ; Supercritical n p > 1 {\displaystyle np>1} : | C 1 | ≈ y n {\displaystyle |C_{1}|\approx yn} where y = y ( n p ) {\displaystyle y=y(np)} is the positive solution to the equation e − p n y = 1 − y {\displaystyle e^{-pny}=1-y} . The largest connected component has high complexity. All other components are simple and small | C 2 | = O ( log n ) {\displaystyle |C_{2}|=O(\log n)} . === Configuration model === The configuration model takes a degree sequence or degree distribution (which subsequently is used to generate a degree sequence) as the input, and produces randomly connected graphs in all respects other than the degree sequence. This means that for a given choice of the degree sequence, the graph is chosen uniformly at random from the set of all graphs that comply with this degree sequence. The degree k {\displaystyle k} of a randomly chosen vertex is an independent and identically distributed random variable with integer values. When E [ k 2 ] − 2 E [ k ] > 0 {\textstyle \mathbb {E} [k^{2}]-2\mathbb {E} [k]>0} , the configuration graph contains the giant connected component, which has infinite size. The rest of the components have finite sizes, which can be quantified with the notion of the size distribution. The probability w ( n ) {\displaystyle w(n)} that a randomly sampled node is connected to a component of size n {\displaystyle n} is given by convolution powers of the degree distribution: w ( n ) = { E [ k ] n − 1 u 1 ∗ n ( n − 2 ) , n > 1 , u ( 0 ) n = 1 , {\displaystyle w(n)={\begin{cases}{\frac {\mathbb {E} [k]}{n-1}}u_{1}^{*n}(n-2),&n>1,\\u(0)&n=1,\end{cases}}} where u ( k ) {\displaystyle u(k)} denotes the degree distribution and u 1 ( k ) = ( k + 1 ) u ( k + 1 ) E [ k ] {\displaystyle u_{1}(k)={\frac {(k+1)u(k+1)}{\mathbb {E} [k]}}} . The giant component can be destroyed by randomly removing the critical fraction p c {\displaystyle p_{c}} of all edges. This process is called percolation on random networks. When the second moment of the degree distribution is finite, E [ k 2 ] < ∞ {\textstyle \mathbb {E} [k^{2}]<\infty } , this critical edge fraction is given by p c = 1 − E [ k ] E [ k 2 ] − E [ k ] {\displaystyle p_{c}=1-{\frac {\mathbb {E} [k]}{\mathbb {E} [k^{2}]-\mathbb {E} [k]}}} , and the average vertex-vertex distance l {\displaystyle l} in the giant component scales logarithmically with the total size of the network, l = O ( log N ) {\displaystyle l=O(\log N)} . In the directed configuration model, the degree of a node is given by two numbers, in-degree k in {\displaystyle k_{\text{in}}} and out-degree k out {\displaystyle k_{\text{out}}} , and consequently, the degree distribution is two-variate. The expected number of in-edges and out-edges coincides, so that E [ k in ] = E [ k out ] {\textstyle \mathbb {E} [k_{\text{in}}]=\mathbb {E} [k_{\text{out}}]} . The directed configuration model contains the giant component iff 2 E [ k in ] E [ k in k out ] − E [ k in ] E [ k out 2 ] − E [ k in ] E [ k in 2 ] + E [ k in 2 ] E [ k out 2 ] − E [ k in k out ] 2 > 0. {\displaystyle 2\mathbb {E} [k_{\text{in}}]\mathbb {E} [k_{\text{in}}k_{\text{out}}]-\mathbb {E} [k_{\text{in}}]\mathbb {E} [k_{\text{out}}^{2}]-\mathbb {E} [k_{\text{in}}]\mathbb {E} [k_{\text{in}}^{2}]+\mathbb {E} [k_{\text{in}}^{2}]\mathbb {E} [k_{\text{out}}^{2}]-\mathbb {E} [k_{\text{in}}k_{\text{out}}]^{2}>0.} Note that E [ k in ] {\textstyle \mathbb {E} [k_{\text{in}}]} and E [ k out ] {\textstyle \mathbb {E} [k_{\text{out}}]} are equal and therefore interchangeable in the latter inequality. The probability that a randomly chosen vertex belongs to a component of size n {\displaystyle n} is given by: h in ( n ) = E [ k i n ] n − 1 u ~ in ∗ n ( n − 2 ) , n > 1 , u ~ in = k in + 1 E [ k in ] ∑ k out ≥ 0 u ( k in + 1 , k out ) , {\displaystyle h_{\text{in}}(n)={\frac {\mathbb {E} [k_{in}]}{n-1}}{\tilde {u}}_{\text{in}}^{*n}(n-2),\;n>1,\;{\tilde {u}}_{\text{in}}={\frac {k_{\text{in}}+1}{\mathbb {E} [k_{\text{in}}]}}\sum \limits _{k_{\text{out}}\geq 0}u(k_{\text{in}}+1,k_{\text{out}}),} for in-components, and h out ( n ) = E [ k out ] n − 1 u ~ out ∗ n ( n − 2 ) , n > 1 , u ~ out = k out + 1 E [ k out ] ∑ k in ≥ 0 u ( k in , k out + 1 ) , {\displaystyle h_{\text{out}}(n)={\frac {\mathbb {E} [k_{\text{out}}]}{n-1}}{\tilde {u}}_{\text{out}}^{*n}(n-2),\;n>1,\;{\tilde {u}}_{\text{out}}={\frac {k_{\text{out}}+1}{\mathbb {E} [k_{\text{out}}]}}\sum \limits _{k_{\text{in}}\geq 0}u(k_{\text{in}},k_{\text{out}}+1),} for out-components. === Watts–Strogatz small world model === The Watts and Strogatz model is a random graph generation model that produces graphs with small-world properties. An initial lattice structure is used to generate a Watts–Strogatz model. Each node in the network is initially linked to its ⟨ k ⟩ {\displaystyle \langle k\rangle } closest neighbors. Another parameter is specified as the rewiring probability. Each edge has a probability p {\displaystyle p} that it will be rewired to the graph as a random edge. The expected number of rewired links in the model is p E = p N ⟨ k ⟩ / 2 {\displaystyle pE=pN\langle k\rangle /2} . As the Watts–Strogatz model begins as a non-random lattice structure, it has a very high clustering coefficient along with a high average path length. Each rewire is likely to create a shortcut between highly connected clusters. As the rewiring probability increases, the clustering coefficient decreases slower than the average path length. In effect, this allows the average path length of the network to decrease significantly with only slight decreases in the clustering coefficient. Higher values of p force more rewired edges, which, in effect, makes the Watts–Strogatz model a random network. === Barabási–Albert (BA) preferential attachment model === The Barabási–Albert model is a random network model used to demonstrate a preferential attachment or a "rich-get-richer" effect. In this model, an edge is most likely to attach to nodes with higher degrees. The network begins with an initial network of m0 nodes. m0 ≥ 2 and the degree of each node in the initial network should be at least 1, otherwise it will always remain disconnected from the rest of the network. In the BA model, new nodes are added to the network one at a time. Each new node is connected to m {\displaystyle m} existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability pi that the new node is connected to node i is p i = k i ∑ j k j , {\displaystyle p_{i}={\frac {k_{i}}{\sum _{j}k_{j}}},} where ki is the degree of node i. Heavily linked nodes ("hubs") tend to quickly accumulate even more links, while nodes with only a few links are unlikely to be chosen as the destination for a new link. The new nodes have a "preference" to attach themselves to the already heavily linked nodes. The degree distribution resulting from the BA model is scale free, in particular, for large degree it is a power law of the form: P ( k ) ∼ k − 3 {\displaystyle P(k)\sim k^{-3}\,} Hubs exhibit high betweenness centrality which allows short paths to exist between nodes. As a result, the BA model tends to have very short average path lengths. The clustering coefficient of this model also tends to 0. The Barabási–Albert model was developed for undirected networks, aiming to explain the universality of the scale-free property, and applied to a wide range of different networks and applications. The directed version of this model is the Price model which was developed to just citation networks. ==== Non-linear preferential attachment ==== In non-linear preferential attachment (NLPA), existing nodes in the network gain new edges proportionally to the node degree raised to a constant positive power, α {\displaystyle \alpha } . Formally, this means that the probability that node i {\displaystyle i} gains a new edge is given by p i = k i α ∑ j k j α . {\displaystyle p_{i}={\frac {k_{i}^{\alpha }}{\sum _{j}k_{j}^{\alpha }}}.} If α = 1 {\displaystyle \alpha =1} , NLPA reduces to the BA model and is referred to as "linear". If 0 < α < 1 {\displaystyle 0<\alpha <1} , NLPA is referred to as "sub-linear" and the degree distribution of the network tends to a stretched exponential distribution. If α > 1 {\displaystyle \alpha >1} , NLPA is referred to as "super-linear" and a small number of nodes connect to almost all other nodes in the network. For both α < 1 {\displaystyle \alpha <1} and α > 1 {\displaystyle \alpha >1} , the scale-free property of the network is broken in the limit of infinite system size. However, if α {\displaystyle \alpha } is only slightly larger than 1 {\displaystyle 1} , NLPA may result in degree distributions which appear to be transiently scale free. === Fitness model === Another model where the key ingredient is the nature of the vertex has been introduced by Caldarelli et al. Here a link is created between two vertices i , j {\displaystyle i,j} with a probability given by a linking function f ( η i , η j ) {\displaystyle f(\eta _{i},\eta _{j})} of the fitnesses of the vertices involved. The degree of a vertex i is given by k ( η i ) = N ∫ 0 ∞ f ( η i , η j ) ρ ( η j ) d η j {\displaystyle k(\eta _{i})=N\int _{0}^{\infty }f(\eta _{i},\eta _{j})\rho (\eta _{j})\,d\eta _{j}} If k ( η i ) {\displaystyle k(\eta _{i})} is an invertible and increasing function of η i {\displaystyle \eta _{i}} , then the probability distribution P ( k ) {\displaystyle P(k)} is given by P ( k ) = ρ ( η ( k ) ) ⋅ η ′ ( k ) {\displaystyle P(k)=\rho (\eta (k))\cdot \eta '(k)} As a result, if the fitnesses η {\displaystyle \eta } are distributed as a power law, then also the node degree does. Less intuitively with a fast decaying probability distribution as ρ ( η ) = e − η {\displaystyle \rho (\eta )=e^{-\eta }} together with a linking function of the kind f ( η i , η j ) = Θ ( η i + η j − Z ) {\displaystyle f(\eta _{i},\eta _{j})=\Theta (\eta _{i}+\eta _{j}-Z)} with Z {\displaystyle Z} a constant and Θ {\displaystyle \Theta } the Heavyside function, we also obtain scale-free networks. Such model has been successfully applied to describe trade between nations by using GDP as fitness for the various nodes i , j {\displaystyle i,j} and a linking function of the kind δ η i η j 1 + δ η i η j . {\displaystyle {\frac {\delta \eta _{i}\eta _{j}}{1+\delta \eta _{i}\eta _{j}}}.} === Exponential random graph models === Exponential Random Graph Models (ERGMs) are a family of statistical models for analyzing data from social and other networks. The Exponential family is a broad family of models for covering many types of data, not just networks. An ERGM is a model from this family which describes networks. We adopt the notation to represent a random graph Y ∈ Y {\displaystyle Y\in {\mathcal {Y}}} via a set of n {\displaystyle n} nodes and a collection of tie variables { Y i j : i = 1 , … , n ; j = 1 , … , n } {\displaystyle \{Y_{ij}:i=1,\dots ,n;j=1,\dots ,n\}} , indexed by pairs of nodes i j {\displaystyle ij} , where Y i j = 1 {\displaystyle Y_{ij}=1} if the nodes ( i , j ) {\displaystyle (i,j)} are connected by an edge and Y i j = 0 {\displaystyle Y_{ij}=0} otherwise. The basic assumption of ERGMs is that the structure in an observed graph y {\displaystyle y} can be explained by a given vector of sufficient statistics s ( y ) {\displaystyle s(y)} which are a function of the observed network and, in some cases, nodal attributes. The probability of a graph y ∈ Y {\displaystyle y\in {\mathcal {Y}}} in an ERGM is defined by: P ( Y = y | θ ) = exp ( θ T s ( y ) ) c ( θ ) {\displaystyle P(Y=y|\theta )={\frac {\exp(\theta ^{T}s(y))}{c(\theta )}}} where θ {\displaystyle \theta } is a vector of model parameters associated with s ( y ) {\displaystyle s(y)} and c ( θ ) = ∑ y ′ ∈ Y exp ( θ T s ( y ′ ) ) {\displaystyle c(\theta )=\sum _{y'\in {\mathcal {Y}}}\exp(\theta ^{T}s(y'))} is a normalising constant. == Network analysis == === Social network analysis === Social network analysis examines the structure of relationships between social entities. These entities are often persons, but may also be groups, organizations, nation states, web sites, scholarly publications. Since the 1970s, the empirical study of networks has played a central role in social science, and many of the mathematical and statistical tools used for studying networks have been first developed in sociology. Amongst many other applications, social network analysis has been used to understand the diffusion of innovation, news and rumors. Similarly, it has been used to examine the spread of both diseases and health-related behaviors. It has also been applied to the study of markets, where it has been used to examine the role of trust in exchange relationships and of social mechanisms in setting prices. Similarly, it has been used to study recruitment into political movements and social organizations. It has also been used to conceptualize scientific disagreements as well as academic prestige. More recently, network analysis (and its close cousin traffic analysis) has gained a significant use in military intelligence, for uncovering insurgent networks of both hierarchical and leaderless nature. In criminology, it is being used to identify influential actors in criminal gangs, offender movements, co-offending, predict criminal activities and make policies. === Dynamic network analysis === Dynamic network analysis examines the shifting structure of relationships among different classes of entities in complex socio-technical systems effects, and reflects social stability and changes such as the emergence of new groups, topics, and leaders. Dynamic Network Analysis focuses on meta-networks composed of multiple types of nodes (entities) and multiple types of links. These entities can be highly varied. Examples include people, organizations, topics, resources, tasks, events, locations, and beliefs. Dynamic network techniques are particularly useful for assessing trends and changes in networks over time, identification of emergent leaders, and examining the co-evolution of people and ideas. === Biological network analysis === With the recent explosion of publicly available high throughput biological data, the analysis of molecular networks has gained significant interest. The type of analysis in this content are closely related to social network analysis, but often focusing on local patterns in the network. For example, network motifs are small subgraphs that are over-represented in the network. Activity motifs are similar over-represented patterns in the attributes of nodes and edges in the network that are over represented given the network structure. The analysis of biological networks has led to the development of network medicine, which looks at the effect of diseases in the interactome. === Semantic network analysis === Semantic network analysis is a sub-field of network analysis that focuses on the relationships between words and concepts in a network. Words are represented as nodes and their proximity or co-occurrences in the text are represented as edges. Semantic networks are therefore graphical representations of knowledge and are commonly used in neurolinguistics and natural language processing applications. Semantic network analysis is also used as a method to analyze large texts and identify the main themes and topics (e.g., of social media posts), to reveal biases (e.g., in news coverage), or even to map an entire research field. === Link analysis === Link analysis is a subset of network analysis, exploring associations between objects. An example may be examining the addresses of suspects and victims, the telephone numbers they have dialed, financial transactions they have partaken in during a given timeframe, and the familial relationships between these subjects as a part of the police investigation. Link analysis here provides the crucial relationships and associations between objects of different types that are not apparent from isolated pieces of information. Computer-assisted or fully automatic computer-based link analysis is increasingly employed by banks and insurance agencies in fraud detection, by telecommunication operators in telecommunication network analysis, by medical sector in epidemiology and pharmacology, in law enforcement investigations, by search engines for relevance rating (and conversely by the spammers for spamdexing and by business owners for search engine optimization), and everywhere else where relationships between many objects have to be analyzed. === Pandemic analysis === The SIR model is one of the most well known algorithms on predicting the spread of global pandemics within an infectious population. ==== Susceptible to infected ==== S = β ( 1 N ) {\displaystyle S=\beta \left({\frac {1}{N}}\right)} The formula above describes the "force" of infection for each susceptible unit in an infectious population, where β is equivalent to the transmission rate of said disease. To track the change of those susceptible in an infectious population: Δ S = β × S 1 N Δ t {\displaystyle \Delta S=\beta \times S{1 \over N}\,\Delta t} ==== Infected to recovered ==== Δ I = μ I Δ t {\displaystyle \Delta I=\mu I\,\Delta t} Over time, the number of those infected fluctuates by: the specified rate of recovery, represented by μ {\displaystyle \mu } but deducted to one over the average infectious period 1 τ {\displaystyle {1 \over \tau }} , the numbered of infectious individuals, I {\displaystyle I} , and the change in time, Δ t {\displaystyle \Delta t} . ==== Infectious period ==== Whether a population will be overcome by a pandemic, with regards to the SIR model, is dependent on the value of R 0 {\displaystyle R_{0}} or the "average people infected by an infected individual." R 0 = β τ = β μ {\displaystyle R_{0}=\beta \tau ={\beta \over \mu }} === Web link analysis === Several Web search ranking algorithms use link-based centrality metrics, including (in order of appearance) Marchiori's Hyper Search, Google's PageRank, Kleinberg's HITS algorithm, the CheiRank and TrustRank algorithms. Link analysis is also conducted in information science and communication science in order to understand and extract information from the structure of collections of web pages. For example, the analysis might be of the interlinking between politicians' web sites or blogs. ==== PageRank ==== PageRank works by randomly picking "nodes" or websites and then with a certain probability, "randomly jumping" to other nodes. By randomly jumping to these other nodes, it helps PageRank completely traverse the network as some webpages exist on the periphery and would not as readily be assessed. Each node, x i {\displaystyle x_{i}} , has a PageRank as defined by the sum of pages j {\displaystyle j} that link to i {\displaystyle i} times one over the outlinks or "out-degree" of j {\displaystyle j} times the "importance" or PageRank of j {\displaystyle j} . x i = ∑ j → i 1 N j x j ( k ) {\displaystyle x_{i}=\sum _{j\rightarrow i}{1 \over N_{j}}x_{j}^{(k)}} ===== Random jumping ===== As explained above, PageRank enlists random jumps in attempts to assign PageRank to every website on the internet. These random jumps find websites that might not be found during the normal search methodologies such as breadth-first search and depth-first search. In an improvement over the aforementioned formula for determining PageRank includes adding these random jump components. Without the random jumps, some pages would receive a PageRank of 0 which would not be good. The first is α {\displaystyle \alpha } , or the probability that a random jump will occur. Contrasting is the "damping factor", or 1 − α {\displaystyle 1-\alpha } . R ( p ) = α N + ( 1 − α ) ∑ j → i 1 N j x j ( k ) {\displaystyle R{(p)}={\alpha \over N}+(1-\alpha )\sum _{j\rightarrow i}{1 \over N_{j}}x_{j}^{(k)}} Another way of looking at it: R ( A ) = ∑ R B B (outlinks) + ⋯ + R n n (outlinks) {\displaystyle R(A)=\sum {R_{B} \over B_{\text{(outlinks)}}}+\cdots +{R_{n} \over n_{\text{(outlinks)}}}} === Centrality measures === Information about the relative importance of nodes and edges in a graph can be obtained through centrality measures, widely used in disciplines like sociology. Centrality measures are essential when a network analysis has to answer questions such as: "Which nodes in the network should be targeted to ensure that a message or information spreads to all or most nodes in the network?" or conversely, "Which nodes should be targeted to curtail the spread of a disease?". Formally established measures of centrality are degree centrality, closeness centrality, betweenness centrality, eigenvector centrality, and katz centrality. The objective of network analysis generally determines the type of centrality measure(s) to be used. Degree centrality of a node in a network is the number of links (vertices) incident on the node. Closeness centrality determines how "close" a node is to other nodes in a network by measuring the sum of the shortest distances (geodesic paths) between that node and all other nodes in the network. Betweenness centrality determines the relative importance of a node by measuring the amount of traffic flowing through that node to other nodes in the network. This is done by measuring the fraction of paths connecting all pairs of nodes and containing the node of interest. Group Betweenness centrality measures the amount of traffic flowing through a group of nodes. Eigenvector centrality is a more sophisticated version of degree centrality where the centrality of a node not only depends on the number of links incident on the node but also the quality of those links. This quality factor is determined by the eigenvectors of the adjacency matrix of the network. Katz centrality of a node is measured by summing the geodesic paths between that node and all (reachable) nodes in the network. These paths are weighted, paths connecting the node with its immediate neighbors carry higher weights than those which connect with nodes farther away from the immediate neighbors. == Spread of content in networks == Content in a complex network can spread via two major methods: conserved spread and non-conserved spread. In conserved spread, the total amount of content that enters a complex network remains constant as it passes through. The model of conserved spread can best be represented by a pitcher containing a fixed amount of water being poured into a series of funnels connected by tubes. The pitcher represents the source, and the water represents the spread content. The funnels and connecting tubing represent the nodes and the connections between nodes, respectively. As the water passes from one funnel into another, the water disappears instantly from the funnel that was previously exposed to the water. In non-conserved spread, the content changes as it enters and passes through a complex network. The model of non-conserved spread can best be represented by a continuously running faucet running through a series of funnels connected by tubes. Here, the amount of water from the source is infinite. Also, any funnels exposed to the water continue to experience the water even as it passes into successive funnels. The non-conserved model is the most suitable for explaining the transmission of most infectious diseases. === The SIR model === In 1927, W. O. Kermack and A. G. McKendrick created a model in which they considered a fixed population with only three compartments, susceptible: S ( t ) {\displaystyle S(t)} , infected, I ( t ) {\displaystyle I(t)} , and recovered, R ( t ) {\displaystyle R(t)} . The compartments used for this model consist of three classes: S ( t ) {\displaystyle S(t)} is used to represent the number of individuals not yet infected with the disease at time t, or those susceptible to the disease I ( t ) {\displaystyle I(t)} denotes the number of individuals who have been infected with the disease and are capable of spreading the disease to those in the susceptible category R ( t ) {\displaystyle R(t)} is the compartment used for those individuals who have been infected and then recovered from the disease. Those in this category are not able to be infected again or to transmit the infection to others. The flow of this model may be considered as follows: S → I → R {\displaystyle {\mathcal {S}}\rightarrow {\mathcal {I}}\rightarrow {\mathcal {R}}} Using a fixed population, N = S ( t ) + I ( t ) + R ( t ) {\displaystyle N=S(t)+I(t)+R(t)} , Kermack and McKendrick derived the following equations: d S d t = − β S I d I d t = β S I − γ I d R d t = γ I {\displaystyle {\begin{aligned}{\frac {dS}{dt}}&=-\beta SI\\[8pt]{\frac {dI}{dt}}&=\beta SI-\gamma I\\[8pt]{\frac {dR}{dt}}&=\gamma I\end{aligned}}} Several assumptions were made in the formulation of these equations: First, an individual in the population must be considered as having an equal probability as every other individual of contracting the disease with a rate of β {\displaystyle \beta } , which is considered the contact or infection rate of the disease. Therefore, an infected individual makes contact and is able to transmit the disease with β N {\displaystyle \beta N} others per unit time and the fraction of contacts by an infected with a susceptible is S / N {\displaystyle S/N} . The number of new infections in unit time per infective then is β N ( S / N ) {\displaystyle \beta N(S/N)} , giving the rate of new infections (or those leaving the susceptible category) as β N ( S / N ) I = β S I {\displaystyle \beta N(S/N)I=\beta SI} (Brauer & Castillo-Chavez, 2001). For the second and third equations, consider the population leaving the susceptible class as equal to the number entering the infected class. However, infectives are leaving this class per unit time to enter the recovered/removed class at a rate γ {\displaystyle \gamma } per unit time (where γ {\displaystyle \gamma } represents the mean recovery rate, or 1 / γ {\displaystyle 1/\gamma } the mean infective period). These processes which occur simultaneously are referred to as the Law of Mass Action, a widely accepted idea that the rate of contact between two groups in a population is proportional to the size of each of the groups concerned (Daley & Gani, 2005). Finally, it is assumed that the rate of infection and recovery is much faster than the time scale of births and deaths and therefore, these factors are ignored in this model. More can be read on this model on the Epidemic model page. === The master equation approach === A master equation can express the behaviour of an undirected growing network where, at each time step, a new node is added to the network, linked to an old node (randomly chosen and without preference). The initial network is formed by two nodes and two links between them at time t = 2 {\displaystyle t=2} , this configuration is necessary only to simplify further calculations, so at time t = n {\displaystyle t=n} the network have n {\displaystyle n} nodes and n {\displaystyle n} links. The master equation for this network is: p ( k , s , t + 1 ) = 1 t p ( k − 1 , s , t ) + ( 1 − 1 t ) p ( k , s , t ) , {\displaystyle p(k,s,t+1)={\frac {1}{t}}p(k-1,s,t)+\left(1-{\frac {1}{t}}\right)p(k,s,t),} where p ( k , s , t ) {\displaystyle p(k,s,t)} is the probability to have the node s {\displaystyle s} with degree k {\displaystyle k} at time t + 1 {\displaystyle t+1} , and s {\displaystyle s} is the time step when this node was added to the network. Note that there are only two ways for an old node s {\displaystyle s} to have k {\displaystyle k} links at time t + 1 {\displaystyle t+1} : The node s {\displaystyle s} have degree k − 1 {\displaystyle k-1} at time t {\displaystyle t} and will be linked by the new node with probability 1 / t {\displaystyle 1/t} Already has degree k {\displaystyle k} at time t {\displaystyle t} and will not be linked by the new node. After simplifying this model, the degree distribution is P ( k ) = 2 − k . {\displaystyle P(k)=2^{-k}.} Based on this growing network, an epidemic model is developed following a simple rule: Each time the new node is added and after choosing the old node to link, a decision is made: whether or not this new node will be infected. The master equation for this epidemic model is: p r ( k , s , t ) = r t 1 t p r ( k − 1 , s , t ) + ( 1 − 1 t ) p r ( k , s , t ) , {\displaystyle p_{r}(k,s,t)=r_{t}{\frac {1}{t}}p_{r}(k-1,s,t)+\left(1-{\frac {1}{t}}\right)p_{r}(k,s,t),} where r t {\displaystyle r_{t}} represents the decision to infect ( r t = 1 {\displaystyle r_{t}=1} ) or not ( r t = 0 {\displaystyle r_{t}=0} ). Solving this master equation, the following solution is obtained: P ~ r ( k ) = ( r 2 ) k . {\displaystyle {\tilde {P}}_{r}(k)=\left({\frac {r}{2}}\right)^{k}.} == Multilayer networks == Multilayer networks are networks with multiple kinds of relations. Attempts to model real-world systems as multidimensional networks have been used in various fields such as social network analysis, economics, history, urban and international transport, ecology, psychology, medicine, biology, commerce, climatology, physics, computational neuroscience, operations management, and finance. == Network optimization == Network problems that involve finding an optimal way of doing something are studied under the name of combinatorial optimization. Examples include network flow, shortest path problem, transport problem, transshipment problem, location problem, matching problem, assignment problem, packing problem, routing problem, critical path analysis and PERT (Program Evaluation & Review Technique). In recent years, innovative research has emerged focusing on the optimization of network problems. For example, Dr. Michael Mann's research which published in IEEE addresses the optimization of transportation networks. == Interdependent networks == Interdependent networks are networks where the functioning of nodes in one network depends on the functioning of nodes in another network. In nature, networks rarely appear in isolation, rather, usually networks are typically elements in larger systems, and interact with elements in that complex system. Such complex dependencies can have non-trivial effects on one another. A well studied example is the interdependency of infrastructure networks, the power stations which form the nodes of the power grid require fuel delivered via a network of roads or pipes and are also controlled via the nodes of communications network. Though the transportation network does not depend on the power network to function, the communications network does. In such infrastructure networks, the disfunction of a critical number of nodes in either the power network or the communication network can lead to cascading failures across the system with potentially catastrophic result to the whole system functioning. If the two networks were treated in isolation, this important feedback effect would not be seen and predictions of network robustness would be greatly overestimated. == See also == == References == == Further reading == A First Course in Network Science, F. Menczer, S. Fortunato, C.A. Davis. (Cambridge University Press, 2020). ISBN 9781108471138. GitHub site with tutorials, datasets, and other resources "Connected: The Power of Six Degrees," https://web.archive.org/web/20111006191031/http://ivl.slis.indiana.edu/km/movies/2008-talas-connected.mov Cohen, R.; Erez, K. (2000). "Resilience of the Internet to random breakdown". Phys. Rev. Lett. 85 (21): 4626–4628. arXiv:cond-mat/0007048. Bibcode:2000PhRvL..85.4626C. CiteSeerX 10.1.1.242.6797. doi:10.1103/physrevlett.85.4626. PMID 11082612. S2CID 15372152. Archived from the original on 2013-05-12. Retrieved 2011-04-12. Pu, Cun-Lai; Wen-; Pei, Jiang; Michaelson, Andrew (2012). "Robustness analysis of network controllability" (PDF). Physica A. 391 (18): 4420–4425. Bibcode:2012PhyA..391.4420P. doi:10.1016/j.physa.2012.04.019. Archived from the original (PDF) on 2016-10-13. Retrieved 2013-09-18. S.N. Dorogovtsev and J.F.F. Mendes, Evolution of Networks: From biological networks to the Internet and WWW, Oxford University Press, 2003, ISBN 0-19-851590-1 Linked: The New Science of Networks, A.-L. Barabási (Perseus Publishing, Cambridge) 'Scale-Free Networks, G. Caldarelli (Oxford University Press, Oxford) Network Science, Committee on Network Science for Future Army Applications, National Research Council. 2005. The National Academies Press (2005)ISBN 0-309-10026-7 Network Science Bulletin, USMA (2007) ISBN 978-1-934808-00-9 The Structure and Dynamics of Networks Mark Newman, Albert-László Barabási, & Duncan J. Watts (The Princeton Press, 2006) ISBN 0-691-11357-2 Dynamical processes on complex networks, Alain Barrat, Marc Barthelemy, Alessandro Vespignani (Cambridge University Press, 2008) ISBN 978-0-521-87950-7 Network Science: Theory and Applications, Ted G. Lewis (Wiley, March 11, 2009) ISBN 0-470-33188-7 Nexus: Small Worlds and the Groundbreaking Theory of Networks, Mark Buchanan (W. W. Norton & Company, June 2003) ISBN 0-393-32442-7 Six Degrees: The Science of a Connected Age, Duncan J. Watts (W. W. Norton & Company, February 17, 2004) ISBN 0-393-32542-3
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Walter Bowman Russell (May 19, 1871 – May 19, 1963) was an American impressionist painter, sculptor, and author. Russell wrote extensively on science topics, but his ideas were rejected by scientists. == Life and career == Born in Boston on May 19, 1871, to Nova Scotian immigrants, Russell left school at age 9 and went to work, then put himself through the Massachusetts Normal Art School. He interrupted his fourth year to spend three months in Paris at the Académie Julian. Biographer Glenn Clark identifies four instructors who prepared him for an art career: Albert Munsell and Ernest Major in Boston, Howard Pyle in Philadelphia, and Jean-Paul Laurens in Paris. In his youth, Russell earned money as a church organist and music teacher, and by conducting a trio in a hotel. Before he left Boston in 1894, Russell married Helen Andrews (1894–1953). They traveled to Paris for their wedding trip and a second term for him at the Académie Julian. After their wedding trip, they settled in New York City in 1894 and had two daughters, Helen and Louise. Russell's rise in New York was immediate; a reporter wrote in 1908, "Mr. Russell came here from Boston and at once became a great artistic success." At age 29, he attracted widespread attention with his allegorical painting The Might of Ages in 1900. The painting represented the United States at the Turin international exhibition and won several awards. By 1903, Russell had published three children's books (The Sea Children, The Bending of the Twig, and The Age of Innocence) and qualified for the Authors Club, which he joined in 1902. Russell made his mark as a builder, creating $30 million worth of cooperative apartments. He is credited with developing "cooperative ownership into an economically sound and workable principle." The Hotel des Artistes on West 67th Street in Manhattan, designed by architect George Mort Pollard, has been described as his masterpiece. Russell was also involved in the initial development of Alwyn Court, at Seventh Avenue and 58th Street in Manhattan, but dropped out before the project's completion. In the 1930s, Russell was employed by Thomas J. Watson, chairman of IBM, as a motivational speaker for IBM employees. He was employed at IBM for twelve years. At age 56 he turned to sculpture and fashioned portrait busts of Thomas Edison, Mark Twain, General MacArthur, John Philip Sousa, Ossip Gabrilowitsch, Charles Goodyear, George Gershwin and others. He rose to top rank as a sculptor. He won the commissions for the Mark Twain Memorial (1934) and for President Franklin D. Roosevelt's Four Freedoms Monument (1943). Russell became a leader in the Science of Man Movement when he was elected president of the Society of Arts and Sciences in 1927. His seven-year tenure generated many articles in the New York Times. The gold medals awarded by the Society were highly valued. As World War II approached, he moved into a top-floor studio at Carnegie Hall, where he lived alone (his estranged wife Helen lived in Connecticut). At the time, he was supervising the casting of the Four Freedoms. This was a low time that required a rejuvenation of his health and spirit. There were reports of his "egotism and self-aggrandizement" that bothered him. == Russell's cosmogony == Russell claimed to have experienced a transformational and revelatory event in May 1921, which he later described in a chapter called "The Story of My Illumining" in the 1950 edition of his Home Study Course. "During that period...I could perceive all motion," and was newly "aware of all things." Russell used the terminology of Richard Maurice Bucke in his book Cosmic Consciousness to explain "cosmic illumination." Later he wrote, "It will be remembered that no one who has ever had [the experience of illumination] has been able to explain it. I deem it my duty to the world to tell of it." This became the subject of his book The Divine Iliad, published in two volumes in 1949. Russell published The Universal One in 1926, The Russell Genero-Radiative Concept in 1930, and defended his ideas in the pages of the New York Times in 1930–1931. He published The Secret of Light in 1947 and A New Concept of the Universe in 1953. Russell copyrighted a spiral shaped Periodic Chart of the Elements in 1926. Russell's cosmogony was described in A New Concept of the Universe, where he wrote that "the cardinal error of science" was "shutting the Creator out of his Creation." Russell never referred to an anthropomorphic god, but rather wrote that "God is the invisible, motionless, sexless, undivided, and unconditioned white Magnetic Light of Mind" which centers all things. "God is provable by laboratory methods," Russell wrote, "The locatable motionless Light which man calls magnetism is the Light which God IS." He wrote that Religion and Science must come together in a New Age. == With Lao Russell at Swannanoa in Virginia 1948–1963 == In 1948, at the age of 77, Russell divorced his first wife and married Daisy Stebbing, aged 44, an immigrant from England and former model and businesswoman, amid some controversy. She changed her name to Lao (after Lao-Tzu, the Chinese illuminate) and they embarked on a cross-country automobile trip from Reno looking for a place to establish a workplace and a museum for his work. They discovered Swannanoa, the palatial estate of a railroad magnate, long abandoned, on a mountaintop on the border of Augusta and Nelson Counties in Virginia, and leased the property for 50 years. There they established the museum and the Walter Russell Foundation, and in 1957 the Commonwealth of Virginia granted a charter for the University of Science and philosophy, a correspondence school with a home study course. (In 2014, the charter was grandfathered back to 1948.) The Russells collaborated on a number of books. The testing of atomic bombs in the atmosphere prompted them to publish Atomic Suicide? in 1957, in which they warned of grave consequences for the planet and humankind if radioactivity was exploited as a world fuel. Walter Russell died in 1963. Lao died in 1988. == Books == The Sea Children, 1901 The Bending of the Twig, 1903 The Age of Innocence, 1904 The Universal One, 1926 The Russell Genero-Radiative Concept or The Cyclic Theory of Continuous Motion, L. Middleditch Co., 1930 The Secret of Light, 1st ed., 1947, 3rd ed., Univ of Science & Philosophy, 1994, ISBN 1-879605-44-9 The Message of the Divine Iliad, vol. 1, 1948, vol. 2, 1949 The Book of Early Whisperings, 1949 The Home Study Course (with Lao Russell), 1st ed., 1950–52 Scientific Answer to Human Relations (with Lao Russell), Univ of Science & Philosophy, 1951 A New Concept of the Universe, Univ of Science & Philosophy, 1953 Atomic Suicide? (with Lao Russell), Univ of Science & Philosophy, 1957 The World Crisis: Its Explanation and Solution, (with Lao Russell), Univ of Science & Philosophy, 1958 The One-World Purpose (with Lao Russell), Univ of Science & Philosophy, 1960 == References == == Further reading == Binder, Timothy A., In the Wave Lies the Secret of Creation, (contains many unpublished drawings of Walter Russell), Univ of Science & Philosophy, 1995, ISBN 1-879605-45-7 == External links == Media related to Walter Russell at Wikimedia Commons Quotations related to Walter Russell at Wikiquote The University of Science and Philosophy
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The Mathematical Sciences are a group of areas of study that includes, in addition to mathematics, those academic disciplines that are primarily mathematical in nature but may not be universally considered subfields of mathematics proper. Statistics, for example, is mathematical in its methods but grew out of bureaucratic and scientific observations, which merged with inverse probability and then grew through applications in some areas of physics, biometrics, and the social sciences to become its own separate, though closely allied, field. Theoretical astronomy, theoretical physics, theoretical and applied mechanics, continuum mechanics, mathematical chemistry, actuarial science, computer science, computational science, data science, operations research, quantitative biology, control theory, econometrics, geophysics and mathematical geosciences are likewise other fields often considered part of the mathematical sciences. Some institutions offer degrees in mathematical sciences (e.g. the United States Military Academy, Stanford University, and University of Khartoum) or applied mathematical sciences (for example, the University of Rhode Island). == See also == Exact sciences – Sciences that admit of absolute precision in their results Formal science – Study of abstract structures described by formal systems Relationship between mathematics and physics == References == == External links == Division of Mathematical Sciences at the National Science Foundation, including a list of disciplinary areas supported Faculty of Mathematical Sciences at University of Khartoum, offers academic degrees in Mathematics, Computer Sciences and Statistics Programs of the Mathematical Sciences Research Institute Research topics studied at the Isaac Newton Institute for Mathematical Sciences Mathematical Sciences in the U.S. FY 2016 Budget; a report from the AAAS
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Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries. The intellectual origins of materials science stem from the Age of Enlightenment, when researchers began to use analytical thinking from chemistry, physics, and engineering to understand ancient, phenomenological observations in metallurgy and mineralogy. Materials science still incorporates elements of physics, chemistry, and engineering. As such, the field was long considered by academic institutions as a sub-field of these related fields. Beginning in the 1940s, materials science began to be more widely recognized as a specific and distinct field of science and engineering, and major technical universities around the world created dedicated schools for its study. Materials scientists emphasize understanding how the history of a material (processing) influences its structure, and thus the material's properties and performance. The understanding of processing -structure-properties relationships is called the materials paradigm. This paradigm is used to advance understanding in a variety of research areas, including nanotechnology, biomaterials, and metallurgy. Materials science is also an important part of forensic engineering and failure analysis – investigating materials, products, structures or components, which fail or do not function as intended, causing personal injury or damage to property. Such investigations are key to understanding, for example, the causes of various aviation accidents and incidents. == History == The material of choice of a given era is often a defining point. Phases such as Stone Age, Bronze Age, Iron Age, and Steel Age are historic, if arbitrary examples. Originally deriving from the manufacture of ceramics and its putative derivative metallurgy, materials science is one of the oldest forms of engineering and applied science. Modern materials science evolved directly from metallurgy, which itself evolved from the use of fire. A major breakthrough in the understanding of materials occurred in the late 19th century, when the American scientist Josiah Willard Gibbs demonstrated that the thermodynamic properties related to atomic structure in various phases are related to the physical properties of a material. Important elements of modern materials science were products of the Space Race; the understanding and engineering of the metallic alloys, and silica and carbon materials, used in building space vehicles enabling the exploration of space. Materials science has driven, and been driven by, the development of revolutionary technologies such as rubbers, plastics, semiconductors, and biomaterials. Before the 1960s (and in some cases decades after), many eventual materials science departments were metallurgy or ceramics engineering departments, reflecting the 19th and early 20th-century emphasis on metals and ceramics. The growth of material science in the United States was catalyzed in part by the Advanced Research Projects Agency, which funded a series of university-hosted laboratories in the early 1960s, "to expand the national program of basic research and training in the materials sciences." In comparison with mechanical engineering, the nascent material science field focused on addressing materials from the macro-level and on the approach that materials are designed on the basis of knowledge of behavior at the microscopic level. Due to the expanded knowledge of the link between atomic and molecular processes as well as the overall properties of materials, the design of materials came to be based on specific desired properties. The materials science field has since broadened to include every class of materials, including ceramics, polymers, semiconductors, magnetic materials, biomaterials, and nanomaterials, generally classified into three distinct groups: ceramics, metals, and polymers. The prominent change in materials science during the recent decades is active usage of computer simulations to find new materials, predict properties and understand phenomena. == Fundamentals == A material is defined as a substance (most often a solid, but other condensed phases can be included) that is intended to be used for certain applications. There are a myriad of materials around us; they can be found in anything from new and advanced materials that are being developed include nanomaterials, biomaterials, and energy materials to name a few. The basis of materials science is studying the interplay between the structure of materials, the processing methods to make that material, and the resulting material properties. The complex combination of these produce the performance of a material in a specific application. Many features across many length scales impact material performance, from the constituent chemical elements, its microstructure, and macroscopic features from processing. Together with the laws of thermodynamics and kinetics materials scientists aim to understand and improve materials. === Structure === Structure is one of the most important components of the field of materials science. The very definition of the field holds that it is concerned with the investigation of "the relationships that exist between the structures and properties of materials". Materials science examines the structure of materials from the atomic scale, all the way up to the macro scale. Characterization is the way materials scientists examine the structure of a material. This involves methods such as diffraction with X-rays, electrons or neutrons, and various forms of spectroscopy and chemical analysis such as Raman spectroscopy, energy-dispersive spectroscopy, chromatography, thermal analysis, electron microscope analysis, etc. Structure is studied in the following levels. ==== Atomic structure ==== Atomic structure deals with the atoms of the materials, and how they are arranged to give rise to molecules, crystals, etc. Much of the electrical, magnetic and chemical properties of materials arise from this level of structure. The length scales involved are in angstroms (Å). The chemical bonding and atomic arrangement (crystallography) are fundamental to studying the properties and behavior of any material. ===== Bonding ===== To obtain a full understanding of the material structure and how it relates to its properties, the materials scientist must study how the different atoms, ions and molecules are arranged and bonded to each other. This involves the study and use of quantum chemistry or quantum physics. Solid-state physics, solid-state chemistry and physical chemistry are also involved in the study of bonding and structure. ===== Crystallography ===== Crystallography is the science that examines the arrangement of atoms in crystalline solids. Crystallography is a useful tool for materials scientists. One of the fundamental concepts regarding the crystal structure of a material includes the unit cell, which is the smallest unit of a crystal lattice (space lattice) that repeats to make up the macroscopic crystal structure. Most common structural materials include parallelpiped and hexagonal lattice types. In single crystals, the effects of the crystalline arrangement of atoms is often easy to see macroscopically, because the natural shapes of crystals reflect the atomic structure. Further, physical properties are often controlled by crystalline defects. The understanding of crystal structures is an important prerequisite for understanding crystallographic defects. Examples of crystal defects consist of dislocations including edges, screws, vacancies, self inter-stitials, and more that are linear, planar, and three dimensional types of defects. New and advanced materials that are being developed include nanomaterials, biomaterials. Mostly, materials do not occur as a single crystal, but in polycrystalline form, as an aggregate of small crystals or grains with different orientations. Because of this, the powder diffraction method, which uses diffraction patterns of polycrystalline samples with a large number of crystals, plays an important role in structural determination. Most materials have a crystalline structure, but some important materials do not exhibit regular crystal structure. Polymers display varying degrees of crystallinity, and many are completely non-crystalline. Glass, some ceramics, and many natural materials are amorphous, not possessing any long-range order in their atomic arrangements. The study of polymers combines elements of chemical and statistical thermodynamics to give thermodynamic and mechanical descriptions of physical properties. ==== Nanostructure ==== Materials, which atoms and molecules form constituents in the nanoscale (i.e., they form nanostructures) are called nanomaterials. Nanomaterials are the subject of intense research in the materials science community due to the unique properties that they exhibit. Nanostructure deals with objects and structures that are in the 1 – 100 nm range. In many materials, atoms or molecules agglomerate to form objects at the nanoscale. This causes many interesting electrical, magnetic, optical, and mechanical properties. In describing nanostructures, it is necessary to differentiate between the number of dimensions on the nanoscale. Nanotextured surfaces have one dimension on the nanoscale, i.e., only the thickness of the surface of an object is between 0.1 and 100 nm. Nanotubes have two dimensions on the nanoscale, i.e., the diameter of the tube is between 0.1 and 100 nm; its length could be much greater. Finally, spherical nanoparticles have three dimensions on the nanoscale, i.e., the particle is between 0.1 and 100 nm in each spatial dimension. The terms nanoparticles and ultrafine particles (UFP) often are used synonymously although UFP can reach into the micrometre range. The term 'nanostructure' is often used, when referring to magnetic technology. Nanoscale structure in biology is often called ultrastructure. ==== Microstructure ==== Microstructure is defined as the structure of a prepared surface or thin foil of material as revealed by a microscope above 25× magnification. It deals with objects from 100 nm to a few cm. The microstructure of a material (which can be broadly classified into metallic, polymeric, ceramic and composite) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behavior, wear resistance, and so on. Most of the traditional materials (such as metals and ceramics) are microstructured. The manufacture of a perfect crystal of a material is physically impossible. For example, any crystalline material will contain defects such as precipitates, grain boundaries (Hall–Petch relationship), vacancies, interstitial atoms or substitutional atoms. The microstructure of materials reveals these larger defects and advances in simulation have allowed an increased understanding of how defects can be used to enhance material properties. ==== Macrostructure ==== Macrostructure is the appearance of a material in the scale millimeters to meters, it is the structure of the material as seen with the naked eye. === Properties === Materials exhibit myriad properties, including the following. Mechanical properties, see Strength of materials Chemical properties, see Chemistry Electrical properties, see Electricity Thermal properties, see Thermodynamics Optical properties, see Optics and Photonics Magnetic properties, see Magnetism The properties of a material determine its usability and hence its engineering application. === Processing === Synthesis and processing involves the creation of a material with the desired micro-nanostructure. A material cannot be used in industry if no economically viable production method for it has been developed. Therefore, developing processing methods for materials that are reasonably effective and cost-efficient is vital to the field of materials science. Different materials require different processing or synthesis methods. For example, the processing of metals has historically defined eras such as the Bronze Age and Iron Age and is studied under the branch of materials science named physical metallurgy. Chemical and physical methods are also used to synthesize other materials such as polymers, ceramics, semiconductors, and thin films. As of the early 21st century, new methods are being developed to synthesize nanomaterials such as graphene. === Thermodynamics === Thermodynamics is concerned with heat and temperature and their relation to energy and work. It defines macroscopic variables, such as internal energy, entropy, and pressure, that partly describe a body of matter or radiation. It states that the behavior of those variables is subject to general constraints common to all materials. These general constraints are expressed in the four laws of thermodynamics. Thermodynamics describes the bulk behavior of the body, not the microscopic behaviors of the very large numbers of its microscopic constituents, such as molecules. The behavior of these microscopic particles is described by, and the laws of thermodynamics are derived from, statistical mechanics. The study of thermodynamics is fundamental to materials science. It forms the foundation to treat general phenomena in materials science and engineering, including chemical reactions, magnetism, polarizability, and elasticity. It explains fundamental tools such as phase diagrams and concepts such as phase equilibrium. === Kinetics === Chemical kinetics is the study of the rates at which systems that are out of equilibrium change under the influence of various forces. When applied to materials science, it deals with how a material changes with time (moves from non-equilibrium to equilibrium state) due to application of a certain field. It details the rate of various processes evolving in materials including shape, size, composition and structure. Diffusion is important in the study of kinetics as this is the most common mechanism by which materials undergo change. Kinetics is essential in processing of materials because, among other things, it details how the microstructure changes with application of heat. == Research == Materials science is a highly active area of research. Together with materials science departments, physics, chemistry, and many engineering departments are involved in materials research. Materials research covers a broad range of topics; the following non-exhaustive list highlights a few important research areas. === Nanomaterials === Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometers (10−9 meter), but is usually 1 nm – 100 nm. Nanomaterials research takes a materials science based approach to nanotechnology, using advances in materials metrology and synthesis, which have been developed in support of microfabrication research. Materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties. The field of nanomaterials is loosely organized, like the traditional field of chemistry, into organic (carbon-based) nanomaterials, such as fullerenes, and inorganic nanomaterials based on other elements, such as silicon. Examples of nanomaterials include fullerenes, carbon nanotubes, nanocrystals, etc. === Biomaterials === A biomaterial is any matter, surface, or construct that interacts with biological systems. Biomaterials science encompasses elements of medicine, biology, chemistry, tissue engineering, and materials science. Biomaterials can be derived either from nature or synthesized in a laboratory using a variety of chemical approaches using metallic components, polymers, bioceramics, or composite materials. They are often intended or adapted for medical applications, such as biomedical devices which perform, augment, or replace a natural function. Such functions may be benign, like being used for a heart valve, or may be bioactive with a more interactive functionality such as hydroxylapatite-coated hip implants. Biomaterials are also used every day in dental applications, surgery, and drug delivery. For example, a construct with impregnated pharmaceutical products can be placed into the body, which permits the prolonged release of a drug over an extended period of time. A biomaterial may also be an autograft, allograft or xenograft used as an organ transplant material. === Electronic, optical, and magnetic === Semiconductors, metals, and ceramics are used today to form highly complex systems, such as integrated electronic circuits, optoelectronic devices, and magnetic and optical mass storage media. These materials form the basis of our modern computing world, and hence research into these materials is of vital importance. Semiconductors are a traditional example of these types of materials. They are materials that have properties that are intermediate between conductors and insulators. Their electrical conductivities are very sensitive to the concentration of impurities, which allows the use of doping to achieve desirable electronic properties. Hence, semiconductors form the basis of the traditional computer. This field also includes new areas of research such as superconducting materials, spintronics, metamaterials, etc. The study of these materials involves knowledge of materials science and solid-state physics or condensed matter physics. === Computational materials science === With continuing increases in computing power, simulating the behavior of materials has become possible. This enables materials scientists to understand behavior and mechanisms, design new materials, and explain properties formerly poorly understood. Efforts surrounding integrated computational materials engineering are now focusing on combining computational methods with experiments to drastically reduce the time and effort to optimize materials properties for a given application. This involves simulating materials at all length scales, using methods such as density functional theory, molecular dynamics, Monte Carlo, dislocation dynamics, phase field, finite element, and many more. == Industry == Radical materials advances can drive the creation of new products or even new industries, but stable industries also employ materials scientists to make incremental improvements and troubleshoot issues with currently used materials. Industrial applications of materials science include materials design, cost-benefit tradeoffs in industrial production of materials, processing methods (casting, rolling, welding, ion implantation, crystal growth, thin-film deposition, sintering, glassblowing, etc.), and analytic methods (characterization methods such as electron microscopy, X-ray diffraction, calorimetry, nuclear microscopy (HEFIB), Rutherford backscattering, neutron diffraction, small-angle X-ray scattering (SAXS), etc.). Besides material characterization, the material scientist or engineer also deals with extracting materials and converting them into useful forms. Thus ingot casting, foundry methods, blast furnace extraction, and electrolytic extraction are all part of the required knowledge of a materials engineer. Often the presence, absence, or variation of minute quantities of secondary elements and compounds in a bulk material will greatly affect the final properties of the materials produced. For example, steels are classified based on 1/10 and 1/100 weight percentages of the carbon and other alloying elements they contain. Thus, the extracting and purifying methods used to extract iron in a blast furnace can affect the quality of steel that is produced. Solid materials are generally grouped into three basic classifications: ceramics, metals, and polymers. This broad classification is based on the empirical makeup and atomic structure of the solid materials, and most solids fall into one of these broad categories. An item that is often made from each of these materials types is the beverage container. The material types used for beverage containers accordingly provide different advantages and disadvantages, depending on the material used. Ceramic (glass) containers are optically transparent, impervious to the passage of carbon dioxide, relatively inexpensive, and are easily recycled, but are also heavy and fracture easily. Metal (aluminum alloy) is relatively strong, is a good barrier to the diffusion of carbon dioxide, and is easily recycled. However, the cans are opaque, expensive to produce, and are easily dented and punctured. Polymers (polyethylene plastic) are relatively strong, can be optically transparent, are inexpensive and lightweight, and can be recyclable, but are not as impervious to the passage of carbon dioxide as aluminum and glass. === Ceramics and glasses === Another application of materials science is the study of ceramics and glasses, typically the most brittle materials with industrial relevance. Many ceramics and glasses exhibit covalent or ionic-covalent bonding with SiO2 (silica) as a fundamental building block. Ceramics – not to be confused with raw, unfired clay – are usually seen in crystalline form. The vast majority of commercial glasses contain a metal oxide fused with silica. At the high temperatures used to prepare glass, the material is a viscous liquid which solidifies into a disordered state upon cooling. Windowpanes and eyeglasses are important examples. Fibers of glass are also used for long-range telecommunication and optical transmission. Scratch resistant Corning Gorilla Glass is a well-known example of the application of materials science to drastically improve the properties of common components. Engineering ceramics are known for their stiffness and stability under high temperatures, compression and electrical stress. Alumina, silicon carbide, and tungsten carbide are made from a fine powder of their constituents in a process of sintering with a binder. Hot pressing provides higher density material. Chemical vapor deposition can place a film of a ceramic on another material. Cermets are ceramic particles containing some metals. The wear resistance of tools is derived from cemented carbides with the metal phase of cobalt and nickel typically added to modify properties. Ceramics can be significantly strengthened for engineering applications using the principle of crack deflection. This process involves the strategic addition of second-phase particles within a ceramic matrix, optimizing their shape, size, and distribution to direct and control crack propagation. This approach enhances fracture toughness, paving the way for the creation of advanced, high-performance ceramics in various industries. === Composites === Another application of materials science in industry is making composite materials. These are structured materials composed of two or more macroscopic phases. Applications range from structural elements such as steel-reinforced concrete, to the thermal insulating tiles, which play a key and integral role in NASA's Space Shuttle thermal protection system, which is used to protect the surface of the shuttle from the heat of re-entry into the Earth's atmosphere. One example is reinforced Carbon-Carbon (RCC), the light gray material, which withstands re-entry temperatures up to 1,510 °C (2,750 °F) and protects the Space Shuttle's wing leading edges and nose cap. RCC is a laminated composite material made from graphite rayon cloth and impregnated with a phenolic resin. After curing at high temperature in an autoclave, the laminate is pyrolized to convert the resin to carbon, impregnated with furfuryl alcohol in a vacuum chamber, and cured-pyrolized to convert the furfuryl alcohol to carbon. To provide oxidation resistance for reusability, the outer layers of the RCC are converted to silicon carbide. Other examples can be seen in the "plastic" casings of television sets, cell-phones and so on. These plastic casings are usually a composite material made up of a thermoplastic matrix such as acrylonitrile butadiene styrene (ABS) in which calcium carbonate chalk, talc, glass fibers or carbon fibers have been added for added strength, bulk, or electrostatic dispersion. These additions may be termed reinforcing fibers, or dispersants, depending on their purpose. === Polymers === Polymers are chemical compounds made up of a large number of identical components linked together like chains. Polymers are the raw materials (the resins) used to make what are commonly called plastics and rubber. Plastics and rubber are the final product, created after one or more polymers or additives have been added to a resin during processing, which is then shaped into a final form. Plastics in former and in current widespread use include polyethylene, polypropylene, polyvinyl chloride (PVC), polystyrene, nylons, polyesters, acrylics, polyurethanes, and polycarbonates. Rubbers include natural rubber, styrene-butadiene rubber, chloroprene, and butadiene rubber. Plastics are generally classified as commodity, specialty and engineering plastics. Polyvinyl chloride (PVC) is widely used, inexpensive, and annual production quantities are large. It lends itself to a vast array of applications, from artificial leather to electrical insulation and cabling, packaging, and containers. Its fabrication and processing are simple and well-established. The versatility of PVC is due to the wide range of plasticisers and other additives that it accepts. The term "additives" in polymer science refers to the chemicals and compounds added to the polymer base to modify its material properties. Polycarbonate would be normally considered an engineering plastic (other examples include PEEK, ABS). Such plastics are valued for their superior strengths and other special material properties. They are usually not used for disposable applications, unlike commodity plastics. Specialty plastics are materials with unique characteristics, such as ultra-high strength, electrical conductivity, electro-fluorescence, high thermal stability, etc. The dividing lines between the various types of plastics is not based on material but rather on their properties and applications. For example, polyethylene (PE) is a cheap, low friction polymer commonly used to make disposable bags for shopping and trash, and is considered a commodity plastic, whereas medium-density polyethylene (MDPE) is used for underground gas and water pipes, and another variety called ultra-high-molecular-weight polyethylene (UHMWPE) is an engineering plastic which is used extensively as the glide rails for industrial equipment and the low-friction socket in implanted hip joints. === Metal alloys === The alloys of iron (steel, stainless steel, cast iron, tool steel, alloy steels) make up the largest proportion of metals today both by quantity and commercial value. Iron alloyed with various proportions of carbon gives low, mid and high carbon steels. An iron-carbon alloy is only considered steel if the carbon level is between 0.01% and 2.00% by weight. For steels, the hardness and tensile strength of the steel is related to the amount of carbon present, with increasing carbon levels also leading to lower ductility and toughness. Heat treatment processes such as quenching and tempering can significantly change these properties, however. In contrast, certain metal alloys exhibit unique properties where their size and density remain unchanged across a range of temperatures. Cast iron is defined as an iron–carbon alloy with more than 2.00%, but less than 6.67% carbon. Stainless steel is defined as a regular steel alloy with greater than 10% by weight alloying content of chromium. Nickel and molybdenum are typically also added in stainless steels. Other significant metallic alloys are those of aluminium, titanium, copper and magnesium. Copper alloys have been known for a long time (since the Bronze Age), while the alloys of the other three metals have been relatively recently developed. Due to the chemical reactivity of these metals, the electrolytic extraction processes required were only developed relatively recently. The alloys of aluminium, titanium and magnesium are also known and valued for their high strength to weight ratios and, in the case of magnesium, their ability to provide electromagnetic shielding. These materials are ideal for situations where high strength to weight ratios are more important than bulk cost, such as in the aerospace industry and certain automotive engineering applications. === Semiconductors === A semiconductor is a material that has a resistivity between a conductor and insulator. Modern day electronics run on semiconductors, and the industry had an estimated US$530 billion market in 2021. Its electronic properties can be greatly altered through intentionally introducing impurities in a process referred to as doping. Semiconductor materials are used to build diodes, transistors, light-emitting diodes (LEDs), and analog and digital electric circuits, among their many uses. Semiconductor devices have replaced thermionic devices like vacuum tubes in most applications. Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs), which consist of a number—from a few to millions—of devices manufactured and interconnected on a single semiconductor substrate. Of all the semiconductors in use today, silicon makes up the largest portion both by quantity and commercial value. Monocrystalline silicon is used to produce wafers used in the semiconductor and electronics industry. Gallium arsenide (GaAs) is the second most popular semiconductor used. Due to its higher electron mobility and saturation velocity compared to silicon, it is a material of choice for high-speed electronics applications. These superior properties are compelling reasons to use GaAs circuitry in mobile phones, satellite communications, microwave point-to-point links and higher frequency radar systems. Other semiconductor materials include germanium, silicon carbide, and gallium nitride and have various applications. == Relation with other fields == Materials science evolved, starting from the 1950s because it was recognized that to create, discover and design new materials, one had to approach it in a unified manner. Thus, materials science and engineering emerged in many ways: renaming and/or combining existing metallurgy and ceramics engineering departments; splitting from existing solid state physics research (itself growing into condensed matter physics); pulling in relatively new polymer engineering and polymer science; recombining from the previous, as well as chemistry, chemical engineering, mechanical engineering, and electrical engineering; and more. The field of materials science and engineering is important both from a scientific perspective, as well as for applications field. Materials are of the utmost importance for engineers (or other applied fields) because usage of the appropriate materials is crucial when designing systems. As a result, materials science is an increasingly important part of an engineer's education. Materials physics is the use of physics to describe the physical properties of materials. It is a synthesis of physical sciences such as chemistry, solid mechanics, solid state physics, and materials science. Materials physics is considered a subset of condensed matter physics and applies fundamental condensed matter concepts to complex multiphase media, including materials of technological interest. Current fields that materials physicists work in include electronic, optical, and magnetic materials, novel materials and structures, quantum phenomena in materials, nonequilibrium physics, and soft condensed matter physics. New experimental and computational tools are constantly improving how materials systems are modeled and studied and are also fields when materials physicists work in. The field is inherently interdisciplinary, and the materials scientists or engineers must be aware and make use of the methods of the physicist, chemist and engineer. Conversely, fields such as life sciences and archaeology can inspire the development of new materials and processes, in bioinspired and paleoinspired approaches. Thus, there remain close relationships with these fields. Conversely, many physicists, chemists and engineers find themselves working in materials science due to the significant overlaps between the fields. == Emerging technologies == == Subdisciplines == The main branches of materials science stem from the four main classes of materials: ceramics, metals, polymers and composites. Ceramic engineering Metallurgy Polymer science and engineering Composite engineering There are additionally broadly applicable, materials independent, endeavors. Materials characterization (spectroscopy, microscopy, diffraction) Computational materials science Materials informatics and selection There are also relatively broad focuses across materials on specific phenomena and techniques. Crystallography Surface science Tribology Microelectronics == Related or interdisciplinary fields == Condensed matter physics, solid-state physics and solid-state chemistry Nanotechnology Mineralogy Supramolecular chemistry Biomaterials science == Professional societies == American Ceramic Society ASM International Association for Iron and Steel Technology Materials Research Society The Minerals, Metals & Materials Society == See also == == References == === Citations === === Bibliography === Ashby, Michael; Hugh Shercliff; David Cebon (2007). Materials: engineering, science, processing and design (1st ed.). Butterworth-Heinemann. ISBN 978-0-7506-8391-3. Askeland, Donald R.; Pradeep P. Phulé (2005). The Science & Engineering of Materials (5th ed.). Thomson-Engineering. ISBN 978-0-534-55396-8. Callister, Jr., William D. (2000). Materials Science and Engineering – An Introduction (5th ed.). John Wiley and Sons. ISBN 978-0-471-32013-5. Eberhart, Mark (2003). Why Things Break: Understanding the World by the Way It Comes Apart. Harmony. ISBN 978-1-4000-4760-4. Gaskell, David R. (1995). Introduction to the Thermodynamics of Materials (4th ed.). Taylor and Francis Publishing. ISBN 978-1-56032-992-3. González-Viñas, W. & Mancini, H.L. (2004). An Introduction to Materials Science. Princeton University Press. ISBN 978-0-691-07097-1. Gordon, James Edward (1984). The New Science of Strong Materials or Why You Don't Fall Through the Floor (eissue ed.). Princeton University Press. ISBN 978-0-691-02380-9. Mathews, F.L. & Rawlings, R.D. (1999). Composite Materials: Engineering and Science. Boca Raton: CRC Press. ISBN 978-0-8493-0621-1. Lewis, P.R.; Reynolds, K. & Gagg, C. (2003). Forensic Materials Engineering: Case Studies. Boca Raton: CRC Press. ISBN 9780849311826. Wachtman, John B. (1996). Mechanical Properties of Ceramics. New York: Wiley-Interscience, John Wiley & Son's. ISBN 978-0-471-13316-2. Walker, P., ed. (1993). Chambers Dictionary of Materials Science and Technology. Chambers Publishing. ISBN 978-0-550-13249-9. Mahajan, S. (2015). "The role of materials science in the evolution of microelectronics". MRS Bulletin. 12 (40): 1079–1088. Bibcode:2015MRSBu..40.1079M. doi:10.1557/mrs.2015.276. == Further reading == Timeline of Materials Science Archived 2011-07-27 at the Wayback Machine at The Minerals, Metals & Materials Society (TMS) – accessed March 2007 Burns, G.; Glazer, A.M. (1990). Space Groups for Scientists and Engineers (2nd ed.). Boston: Academic Press, Inc. ISBN 978-0-12-145761-7. Cullity, B.D. (1978). Elements of X-Ray Diffraction (2nd ed.). Reading, Massachusetts: Addison-Wesley Publishing Company. ISBN 978-0-534-55396-8. Giacovazzo, C; Monaco HL; Viterbo D; Scordari F; Gilli G; Zanotti G; Catti M (1992). Fundamentals of Crystallography. Oxford: Oxford University Press. ISBN 978-0-19-855578-0. Green, D.J.; Hannink, R.; Swain, M.V. (1989). Transformation Toughening of Ceramics. Boca Raton: CRC Press. ISBN 978-0-8493-6594-2. Lovesey, S. W. (1984). Theory of Neutron Scattering from Condensed Matter; Volume 1: Neutron Scattering. Oxford: Clarendon Press. ISBN 978-0-19-852015-3. Lovesey, S. W. (1984). Theory of Neutron Scattering from Condensed Matter; Volume 2: Condensed Matter. Oxford: Clarendon Press. ISBN 978-0-19-852017-7. O'Keeffe, M.; Hyde, B.G. (1996). "Crystal Structures; I. Patterns and Symmetry". Zeitschrift für Kristallographie – Crystalline Materials. 212 (12). Washington, DC: Mineralogical Society of America, Monograph Series: 899. Bibcode:1997ZK....212..899K. doi:10.1524/zkri.1997.212.12.899. ISBN 978-0-939950-40-9. Squires, G.L. (1996). Introduction to the Theory of Thermal Neutron Scattering (2nd ed.). Mineola, New York: Dover Publications Inc. ISBN 978-0-486-69447-4. Young, R.A., ed. (1993). The Rietveld Method. Oxford: Oxford University Press & International Union of Crystallography. ISBN 978-0-19-855577-3. == External links == MS&T conference organized by the main materials societies MIT OpenCourseWare for MSE
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https://en.wikipedia.org/wiki/Materials_science
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Science fiction (often shortened to sci-fi or abbreviated SF) is a genre of speculative fiction that stereotypically deals with imaginative and futuristic concepts: these concepts include advanced science and technology, space exploration, time travel, parallel universes, and extraterrestrial life. The genre can explore science and technology in different ways, such as human responses to or the consequences of theoretical new advancements. Science fiction is related to fantasy (together abbreviated SF&F), horror, and superhero fiction, and it contains many subgenres. The genre's exact definition has long been disputed among authors, critics, scholars, and readers. Major subgenres include hard science fiction, which emphasizes scientific accuracy, and soft science fiction, which focuses on social sciences. Other notable subgenres are cyberpunk, which explores the interface between technology and society, and climate fiction, which addresses environmental issues. Precedents for science fiction are claimed to exist as far back as antiquity, but the modern genre arose primarily in the 19th and early 20th centuries, when popular writers began looking to technological progress for inspiration and speculation. Mary Shelley's Frankenstein, written in 1818, is often credited as the first true science fiction novel. Jules Verne and H.G. Wells are pivotal figures in the genre's development. In the 20th century, the genre grew during the Golden Age of Science Fiction; it expanded with the introduction of space operas, dystopian literature, and pulp magazines. Science fiction has come to influence not only literature, but also film, television, and culture at large. Science fiction can criticize present-day society and explore alternatives, as well as provide entertainment and inspire a "sense of wonder". == Definitions == According to Isaac Asimov, "Science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in science and technology." Robert A. Heinlein wrote that "A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method." American science fiction author and editor Lester del Rey wrote, "Even the devoted aficionado or fan—has a hard time trying to explain what science fiction is," and the lack of a "full satisfactory definition" is because "there are no easily delineated limits to science fiction." Another definition comes from The Literature Book by DK and is, "scenarios that are at the time of writing technologically impossible, extrapolating from present-day science...[,]...or that deal with some form of speculative science-based conceit, such as a society (on Earth or another planet) that has developed in wholly different ways from our own." There is a tendency among science fiction enthusiasts as their own arbiter in deciding what exactly constitutes science fiction. David Seed says it may be more useful to talk about science fiction as the intersection of other more concrete subgenres. Damon Knight summed up the difficulty, saying "Science fiction is what we point to when we say it." === Alternative terms === Forrest J Ackerman has been credited with first using the term "sci-fi" (analogous to the then-trendy "hi-fi") in about 1954. The first known use in print was a description of Donovan's Brain by movie critic Jesse Zunser in January 1954. As science fiction entered popular culture, writers and fans active in the field came to associate the term with low-budget, low-tech "B-movies" and with low-quality pulp science fiction. By the 1970s, critics within the field, such as Damon Knight and Terry Carr, were using "sci fi" to distinguish hack-work from serious science fiction. Peter Nicholls writes that "SF" (or "sf") is "the preferred abbreviation within the community of sf writers and readers." Robert Heinlein found even "science fiction" insufficient for certain types of works in this genre, and suggested the term speculative fiction to be used instead for those that are more "serious" or "thoughtful". == History == Some scholars assert that science fiction had its beginnings in ancient times, when the line between myth and fact was blurred. Written in the 2nd century CE by the satirist Lucian, A True Story contains many themes and tropes characteristic of modern science fiction, including travel to other worlds, extraterrestrial lifeforms, interplanetary warfare, and artificial life. Some consider it the first science fiction novel. Some of the stories from The Arabian Nights, along with the 10th-century The Tale of the Bamboo Cutter and Ibn al-Nafis's 13th-century Theologus Autodidactus, are also argued to contain elements of science fiction. Several books written during the Scientific Revolution and later the Age of Enlightenment are considered true works of science-fantasy. Francis Bacon's New Atlantis (1627), Johannes Kepler's Somnium (1634), Athanasius Kircher's Itinerarium extaticum (1656), Cyrano de Bergerac's Comical History of the States and Empires of the Moon (1657) and The States and Empires of the Sun (1662), Margaret Cavendish's "The Blazing World" (1666), Jonathan Swift's Gulliver's Travels (1726), Ludvig Holberg's Nicolai Klimii Iter Subterraneum (1741) and Voltaire's Micromégas (1752). Isaac Asimov and Carl Sagan considered Johannes Kepler's Somnium the first science fiction story; it depicts a journey to the Moon and how the Earth's motion is seen from there. Kepler has been called the "father of science fiction". Following the 17th-century development of the novel as a literary form, Mary Shelley's Frankenstein (1818) and The Last Man (1826) helped define the form of the science fiction novel. Brian Aldiss has argued that Frankenstein was the first work of science fiction. Edgar Allan Poe wrote several stories considered to be science fiction, including "The Unparalleled Adventure of One Hans Pfaall" (1835), which featured a trip to the Moon. Jules Verne was noted for his attention to detail and scientific accuracy, especially in Twenty Thousand Leagues Under the Seas (1870). In 1887, the novel El anacronópete by Spanish author Enrique Gaspar y Rimbau introduced the first time machine. An early French/Belgian science fiction writer was J.-H. Rosny aîné (1856–1940). Rosny's masterpiece is Les Navigateurs de l'Infini (The Navigators of Infinity) (1925) in which the word astronaut, "astronautique", was used for the first time. Many critics consider H. G. Wells one of science fiction's most important authors, or even "the Shakespeare of science fiction". His works include The Time Machine (1895), The Island of Doctor Moreau (1896), The Invisible Man (1897), and The War of the Worlds (1898). His science fiction imagined alien invasion, biological engineering, invisibility, and time travel. In his non-fiction futurologist works he predicted the advent of airplanes, military tanks, nuclear weapons, satellite television, space travel, and something resembling the World Wide Web. Edgar Rice Burroughs's A Princess of Mars, published in 1912, was the first of his three-decade-long planetary romance series of Barsoom novels, which were set on Mars and featured John Carter as the hero. These novels were predecessors to YA novels, and drew inspiration from European science fiction and American Western novels. In 1924, We by Russian writer Yevgeny Zamyatin, one of the first dystopian novels, was published. It describes a world of harmony and conformity within a united totalitarian state. It influenced the emergence of dystopia as a literary genre. In 1926, Hugo Gernsback published the first American science fiction magazine, Amazing Stories. In its first issue he wrote: By 'scientifiction' I mean the Jules Verne, H. G. Wells and Edgar Allan Poe type of story—a charming romance intermingled with scientific fact and prophetic vision... Not only do these amazing tales make tremendously interesting reading—they are always instructive. They supply knowledge... in a very palatable form... New adventures pictured for us in the scientifiction of today are not at all impossible of realization tomorrow... Many great science stories destined to be of historical interest are still to be written... Posterity will point to them as having blazed a new trail, not only in literature and fiction, but progress as well. In 1928, E. E. "Doc" Smith's first published work, The Skylark of Space, written in collaboration with Lee Hawkins Garby, appeared in Amazing Stories. It is often called the first great space opera. The same year, Philip Francis Nowlan's original Buck Rogers story, Armageddon 2419, also appeared in Amazing Stories. This was followed by a Buck Rogers comic strip, the first serious science fiction comic. Last and First Men: A Story of the Near and Far Future is a "future history" science fiction novel written in 1930 by the British author Olaf Stapledon. A work of unprecedented scale in the genre, it describes the history of humanity from the present onwards across two billion years. In 1937, John W. Campbell became editor of Astounding Science Fiction, an event that is sometimes considered the beginning of the Golden Age of Science Fiction, which was characterized by stories celebrating scientific achievement and progress. The "Golden Age" is often said to have ended in 1946, but sometimes the late 1940s and the 1950s are included. In 1942, Isaac Asimov started his Foundation series, which chronicles the rise and fall of galactic empires and introduced psychohistory. The series was later awarded a one-time Hugo Award for "Best All-Time Series". Theodore Sturgeon's More Than Human (1953) explored possible future human evolution. In 1957, Andromeda: A Space-Age Tale by the Russian writer and paleontologist Ivan Yefremov presented a view of a future interstellar communist civilization and is considered one of the most important Soviet science fiction novels. In 1959, Robert A. Heinlein's Starship Troopers marked a departure from his earlier juvenile stories and novels. It is one of the first and most influential examples of military science fiction, and introduced the concept of powered armor exoskeletons. The German space opera series Perry Rhodan, written by various authors, started in 1961 with an account of the first Moon landing and has since expanded in space to multiple universes, and in time by billions of years. It has become the most popular science fiction book series of all time. In the 1960s and 1970s, New Wave science fiction was known for its embrace of a high degree of experimentation, both in form and in content, and a highbrow and self-consciously "literary" or "artistic" sensibility. In 1961, Solaris by Stanisław Lem was published in Poland. The novel dealt with the theme of human limitations as its characters attempted to study a seemingly intelligent ocean on a newly discovered planet. Lem's work anticipated the creation of microrobots and micromachinery, nanotechnology, smartdust, virtual reality, and artificial intelligence (including swarm intelligence), as well as developing the ideas of "necroevolution" and the creation of artificial worlds. In 1965, Dune by Frank Herbert featured a much more complex and detailed imagined future society than had previously in most science fiction. In 1967 Anne McCaffrey began her Dragonriders of Pern science fantasy series. Two of the novellas included in the first novel, Dragonflight, made McCaffrey the first woman to win a Hugo or Nebula Award. In 1968, Philip K. Dick's Do Androids Dream of Electric Sheep? was published. It is the literary source of the Blade Runner movie franchise. In 1969, The Left Hand of Darkness by Ursula K. Le Guin was set on a planet in which the inhabitants have no fixed gender. It is one of the most influential examples of social science fiction, feminist science fiction, and anthropological science fiction. In 1979, Science Fiction World began publication in the People's Republic of China. It dominates the Chinese science fiction magazine market, at one time claiming a circulation of 300,000 copies per issue and an estimated 3–5 readers per copy (giving it a total estimated readership of at least 1 million), making it the world's most popular science fiction periodical. In 1984, William Gibson's first novel, Neuromancer, helped popularize cyberpunk and the word "cyberspace", a term he originally coined in his 1982 short story Burning Chrome. In the same year, Octavia Butler's short story "Speech Sounds" won the Hugo Award for Short Story. She went on to explore in her work of racial injustice, global warming, women's rights, and political conflict. In 1995, she became the first science-fiction author to receive a MacArthur Fellowship. In 1986, Shards of Honor by Lois McMaster Bujold began her Vorkosigan Saga. 1992's Snow Crash by Neal Stephenson predicted immense social upheaval due to the information revolution. In 2007, Liu Cixin's novel, The Three-Body Problem, was published in China. It was translated into English by Ken Liu and published by Tor Books in 2014, and won the 2015 Hugo Award for Best Novel, making Liu the first Asian writer to win the award. Emerging themes in late 20th and early 21st century science fiction include environmental issues, the implications of the Internet and the expanding information universe, questions about biotechnology, nanotechnology, and post-scarcity societies. Recent trends and subgenres include steampunk, biopunk, and mundane science fiction. === Film === The first, or at least one of the first, recorded science fiction film is 1902's A Trip to the Moon, directed by French filmmaker Georges Méliès. It was influential on later filmmakers, bringing a different kind of creativity and fantasy. Méliès's innovative editing and special effects techniques were widely imitated and became important elements of the cinematic medium. 1927's Metropolis, directed by Fritz Lang, is the first feature-length science fiction film. Though not well received in its time, it is now considered a great and influential film. In 1954, Godzilla, directed by Ishirō Honda, began the kaiju subgenre of science fiction film, which feature large creatures of any form, usually attacking a major city or engaging other monsters in battle. 1968's 2001: A Space Odyssey, directed by Stanley Kubrick and based on the work of Arthur C. Clarke, rose above the mostly B-movie offerings up to that time both in scope and quality, and influenced later science fiction films. That same year, Planet of the Apes (the original), directed by Franklin J. Schaffner and based on the 1963 French novel La Planète des Singes by Pierre Boulle, was released to popular and critical acclaim, its vivid depiction of a post-apocalyptic world in which intelligent apes dominate humans. In 1977, George Lucas began the Star Wars film series with the film now identified as "Star Wars: Episode IV – A New Hope." The series, often called a space opera, went on to become a worldwide popular culture phenomenon, and the third-highest-grossing film series of all time. Since the 1980s, science fiction films, along with fantasy, horror, and superhero films, have dominated Hollywood's big-budget productions. Science fiction films often "cross-over" with other genres, including film noir (Blade Runner - 1982), family film (E.T. the Extra-Terrestrial - 1982), war film (Enemy Mine - 1985), comedy (Spaceballs - 1987, Galaxy Quest - 1999), animation (WALL-E – 2008, Big Hero 6 – 2014), Western (Serenity – 2005), action (Edge of Tomorrow – 2014, The Matrix – 1999), adventure (Jupiter Ascending – 2015, Interstellar – 2014), mystery (Minority Report – 2002), thriller (Ex Machina – 2014), drama (Melancholia – 2011, Predestination – 2014), and romance (Eternal Sunshine of the Spotless Mind – 2004, Her – 2013). === Television === Science fiction and television have consistently been in a close relationship. Television or television-like technologies frequently appeared in science fiction long before television itself became widely available in the late 1940s and early 1950s. The first known science fiction television program was a thirty-five-minute adapted excerpt of the play RUR, written by the Czech playwright Karel Čapek, broadcast live from the BBC's Alexandra Palace studios on 11 February 1938. The first popular science fiction program on American television was the children's adventure serial Captain Video and His Video Rangers, which ran from June 1949 to April 1955. The Twilight Zone (the original series), produced and narrated by Rod Serling, who also wrote or co-wrote most of the episodes, ran from 1959 to 1964. It featured fantasy, suspense, and horror as well as science fiction, with each episode being a complete story. Critics have ranked it as one of the best TV programs of any genre. The animated series The Jetsons, while intended as comedy and only running for one season (1962–1963), predicted many inventions now in common use: flat-screen televisions, newspapers on a computer-like screen, computer viruses, video chat, tanning beds, home treadmills, and more. In 1963, the time travel-themed Doctor Who premiered on BBC Television. The original series ran until 1989 and was revived in 2005. It has been extremely popular worldwide and has greatly influenced later TV science fiction. Other programs in the 1960s included The Outer Limits (1963–1965), Lost in Space (1965–1968), and The Prisoner (1967). Star Trek (the original series), created by Gene Roddenberry, premiered in 1966 on NBC Television and ran for three seasons. It combined elements of space opera and Space Western. Only mildly successful at first, the series gained popularity through syndication and extraordinary fan interest. It became a very popular and influential franchise with many films, television shows, novels, and other works and products. Star Trek: The Next Generation (1987–1994) led to six additional live action Star Trek shows: Deep Space Nine (1993–1999), Voyager (1995–2001), Enterprise (2001–2005), Discovery (2017–2024), Picard (2020–2023), and Strange New Worlds (2022–present), with more in some form of development. The miniseries V premiered in 1983 on NBC. It depicted an attempted takeover of Earth by reptilian aliens. Red Dwarf, a comic science fiction series aired on BBC Two between 1988 and 1999, and on Dave since 2009. The X-Files, which featured UFOs and conspiracy theories, was created by Chris Carter and broadcast by Fox Broadcasting Company from 1993 to 2002, and again from 2016 to 2018. Stargate, a film about ancient astronauts and interstellar teleportation, was released in 1994. Stargate SG-1 premiered in 1997 and ran for 10 seasons (1997–2007). Spin-off series included Stargate Infinity (2002–2003), Stargate Atlantis (2004–2009), and Stargate Universe (2009–2011). Other 1990s series included Quantum Leap (1989–1993) and Babylon 5 (1994–1999). Syfy, launched in 1992 as The Sci-Fi Channel, specializes in science fiction, supernatural horror, and fantasy. The space-Western series Firefly premiered in 2002 on Fox. It is set in the year 2517, after the arrival of humans in a new star system, and follows the adventures of the renegade crew of Serenity, a "Firefly-class" spaceship. Orphan Black began its five-season run in 2013, about a woman who assumes the identity of one of her several genetically identical human clones. In late 2015, Syfy premiered The Expanse to great critical acclaim, an American TV series about humanity's colonization of the Solar System. Its later seasons would then be aired through Amazon Prime Video. == Social influence == Science fiction's rapid rise in popularity during the first half of the 20th century was closely tied to the popular respect paid to science at that time, as well as the rapid pace of technological innovation and new inventions. Science fiction has often predicted scientific and technological progress. Some works predict that new inventions and progress will tend to improve life and society, for instance the stories of Arthur C. Clarke and Star Trek. Others, such as H.G. Wells's The Time Machine and Aldous Huxley's Brave New World, warn about possible negative consequences. In 2001 the National Science Foundation conducted a survey on "Public Attitudes and Public Understanding: Science Fiction and Pseudoscience". It found that people who read or prefer science fiction may think about or relate to science differently than other people. They also tend to support the space program and the idea of contacting extraterrestrial civilizations. Carl Sagan wrote: "Many scientists deeply involved in the exploration of the solar system (myself among them) were first turned in that direction by science fiction." Science fiction has predicted several existing inventions, such as the atomic bomb, robots, and borazon. In the 2020 series Away astronauts use a Mars rover called InSight to listen intently for a landing on Mars. In 2022 scientists used InSight to listen for the landing of a spacecraft. Science fiction can act as a vehicle to analyze and recognize a society's past, present, and potential future social relationships with the other. Science fiction offers a medium and representation of alterity and differences in social identity. Brian Aldiss described science fiction as "cultural wallpaper". This widespread influence can be found in trends for writers to employ science fiction as a tool for advocacy and generating cultural insights, as well as for educators when teaching across a range of academic disciplines not limited to the natural sciences. Scholar and science fiction critic George Edgar Slusser said that science fiction "is the one real international literary form we have today, and as such has branched out to visual media, interactive media and on to whatever new media the world will invent in the 21st century. Crossover issues between the sciences and the humanities are crucial for the century to come." === As protest literature === Science fiction has sometimes been used as a means of social protest. George Orwell's Nineteen Eighty-Four (1949) is an important work of dystopian science fiction. It is often invoked in protests against governments and leaders who are seen as totalitarian. James Cameron's 2009 film Avatar was intended as a protest against imperialism, and specifically the European colonization of the Americas. Science fiction in Latin America and Spain explore the concept of authoritarianism. Robots, artificial humans, human clones, intelligent computers, and their possible conflicts with human society have all been major themes of science fiction since, at least, the publication of Shelly's Frankenstein. Some critics have seen this as reflecting authors' concerns over the social alienation seen in modern society. Feminist science fiction poses questions about social issues such as how society constructs gender roles, the role reproduction plays in defining gender, and the inequitable political or personal power of one gender over others. Some works have illustrated these themes using utopias to explore a society in which gender differences or gender power imbalances do not exist, or dystopias to explore worlds in which gender inequalities are intensified, thus asserting a need for feminist work to continue. Climate fiction, or "cli-fi", deals with issues concerning climate change and global warming. University courses on literature and environmental issues may include climate change fiction in their syllabi, and it is often discussed by other media outside of science fiction fandom. Libertarian science fiction focuses on the politics and social order implied by right libertarian philosophies with an emphasis on individualism and private property, and in some cases anti-statism. Robert A. Heinlein is one of the most popular authors of this subgenre, including The Moon is a Harsh Mistress and Stranger in a Strange Land. Science fiction comedy often satirizes and criticizes present-day society, and sometimes makes fun of the conventions and clichés of more serious science fiction. === Sense of wonder === Science fiction is often said to inspire a "sense of wonder". Science fiction editor, publisher and critic David Hartwell wrote: Science fiction's appeal lies in combination of the rational, the believable, with the miraculous. It is an appeal to the sense of wonder. Carl Sagan said: One of the great benefits of science fiction is that it can convey bits and pieces, hints, and phrases, of knowledge unknown or inaccessible to the reader . . . works you ponder over as the water is running out of the bathtub or as you walk through the woods in an early winter snowfall. In 1967, Isaac Asimov commented on the changes then occurring in the science fiction community: And because today's real life so resembles day-before-yesterday's fantasy, the old-time fans are restless. Deep within, whether they admit it or not, is a feeling of disappointment and even outrage that the outer world has invaded their private domain. They feel the loss of a 'sense of wonder' because what was once truly confined to 'wonder' has now become prosaic and mundane. == Science fiction studies == The science fiction studies is the critical assessment interpretation, and discussion of science fiction literature, film, TV shows, new media, fandom, and fan fiction. Science fiction scholars study science fiction to better understand it and its relationship to science, technology, politics, other genres, and culture-at-large. Science fiction studies began around the turn of the 20th century, but it was not until later that science fiction studies solidified as a discipline with the publication of the academic journals Extrapolation (1959), Foundation: The International Review of Science Fiction (1972), and Science Fiction Studies (1973), and the establishment of the oldest organizations devoted to the study of science fiction in 1970, the Science Fiction Research Association and the Science Fiction Foundation. The field has grown considerably since the 1970s with the establishment of more journals, organizations, and conferences, as well as science fiction degree-granting programs such as those offered by the University of Liverpool. === Classification === Science fiction has historically been sub-divided between hard science fiction and soft science fiction, with the division centering on the feasibility of the science. However, this distinction has come under increasing scrutiny in the 21st century. Some authors, such as Tade Thompson and Jeff VanderMeer, have pointed out that stories that focus explicitly on physics, astronomy, mathematics, and engineering tend to be considered "hard" science fiction, while stories that focus on botany, mycology, zoology, and the social sciences tend to be categorized as "soft", regardless of the relative rigor of the science. Max Gladstone defined "hard" science fiction as stories "where the math works", but pointed out that this ends up with stories that often seem "weirdly dated", as scientific paradigms shift over time. Michael Swanwick dismissed the traditional definition of "hard" SF altogether, instead saying that it was defined by characters striving to solve problems "in the right way–with determination, a touch of stoicism, and the consciousness that the universe is not on his or her side." Ursula K. Le Guin also criticized the more traditional view on the difference between "hard" and "soft" SF: "The 'hard' science fiction writers dismiss everything except, well, physics, astronomy, and maybe chemistry. Biology, sociology, anthropology—that's not science to them, that's soft stuff. They're not that interested in what human beings do, really. But I am. I draw on the social sciences a great deal." === Literary merit === Many critics remain skeptical of the literary value of science fiction and other forms of genre fiction, though some accepted authors have written works argued by opponents to constitute science fiction. Mary Shelley wrote a number of scientific romance novels in the Gothic literature tradition, including Frankenstein; or, The Modern Prometheus (1818). Kurt Vonnegut was a highly respected American author whose works have been argued by some to contain science fiction premises or themes. Other science fiction authors whose works are widely considered to be "serious" literature include Ray Bradbury (including, especially, Fahrenheit 451 (1953) and The Martian Chronicles (1951)), Arthur C. Clarke (especially for Childhood's End), and Paul Myron Anthony Linebarger, writing under the name Cordwainer Smith. Doris Lessing, who was later awarded the Nobel Prize in Literature, wrote a series of five SF novels, Canopus in Argos: Archives (1979–1983), which depict the efforts of more advanced species and civilizations to influence those less advanced, including humans on Earth. David Barnett has pointed out that there are books such as The Road (2006) by Cormac McCarthy, Cloud Atlas (2004) by David Mitchell, The Gone-Away World (2008) by Nick Harkaway, The Stone Gods (2007) by Jeanette Winterson, and Oryx and Crake (2003) by Margaret Atwood, which use recognizable science fiction tropes, but which are not classified by their authors and publishers as science fiction. Atwood in particular argued against the categorization of works like the Handmaid's Tale as science fiction, labeling it, Oryx, and the Testaments as speculative fiction and deriding science fiction as "talking squids in outer space." In his book "The Western Canon", literary critic Harold Bloom includes Brave New World, Stanisław Lem's Solaris, Kurt Vonnegut's Cat's Cradle, and The Left Hand of Darkness as culturally and aesthetically significant works of western literature, though Lem actively spurned the Western label of "science fiction". In her 1976 essay "Science Fiction and Mrs Brown", Ursula K. Le Guin was asked: "Can a science fiction writer write a novel?" She answered: "I believe that all novels ... deal with character... The great novelists have brought us to see whatever they wish us to see through some character. Otherwise, they would not be novelists, but poets, historians, or pamphleteers." Orson Scott Card, best known for his 1985 science fiction novel Ender's Game, has postulated that in science fiction the message and intellectual significance of the work are contained within the story itself and, therefore, does not require accepted literary devices and techniques he instead characterized as gimmicks or literary games. Jonathan Lethem, in a 1998 essay in the Village Voice entitled "Close Encounters: The Squandered Promise of Science Fiction", suggested that the point in 1973 when Thomas Pynchon's Gravity's Rainbow was nominated for the Nebula Award and was passed over in favor of Clarke's Rendezvous with Rama, stands as "a hidden tombstone marking the death of the hope that SF was about to merge with the mainstream." In the same year science fiction author and physicist Gregory Benford wrote: "SF is perhaps the defining genre of the twentieth century, although its conquering armies are still camped outside the Rome of the literary citadels." == Community == === Authors === Science fiction has been written by diverse authors from around the world. According to 2013 statistics by the science fiction publisher Tor Books, men outnumber women by 78% to 22% among submissions to the publisher. A controversy about voting slates in the 2015 Hugo Awards highlighted tensions in the science fiction community between a trend of increasingly diverse works and authors being honored by awards, and reaction by groups of authors and fans who preferred what they considered more "traditional" science fiction. === Awards === Among the most significant and well-known awards for science fiction are the Hugo Award for literature, presented by the World Science Fiction Society at Worldcon, and voted on by fans; the Nebula Award for literature, presented by the Science Fiction and Fantasy Writers of America, and voted on by the community of authors; the John W. Campbell Memorial Award for Best Science Fiction Novel, presented by a jury of writers; and the Theodore Sturgeon Memorial Award for short fiction, presented by a jury. One notable award for science fiction films and TV programs is the Saturn Award, which is presented annually by The Academy of Science Fiction, Fantasy, and Horror Films. There are other national awards, like Canada's Prix Aurora Awards, regional awards, like the Endeavour Award presented at Orycon for works from the U.S. Pacific Northwest, and special interest or subgenre awards such as the Chesley Award for art, presented by the Association of Science Fiction & Fantasy Artists, or the World Fantasy Award for fantasy. Magazines may organize reader polls, notably the Locus Award. === Conventions === Conventions (in fandom, often shortened as "cons", such as "comic-con") are held in cities around the world, catering to a local, regional, national, or international membership. General-interest conventions cover all aspects of science fiction, while others focus on a particular interest like media fandom, filking, and others. Most science fiction conventions are organized by volunteers in non-profit groups, though most media-oriented events are organized by commercial promoters. === Fandom and fanzines === Science fiction fandom emerged from the letters column in Amazing Stories magazine. Soon fans began writing letters to each other, and then grouping their comments together in informal publications that became known as fanzines. Once in regular contact, fans wanted to meet each other and organized local clubs. In the 1930s, the first science fiction conventions gathered fans from a wider area. The earliest organized online fandom was the SF Lovers Community, originally a mailing list in the late 1970s with a text archive file that was updated regularly. In the 1980s, Usenet groups greatly expanded the circle of fans online. In the 1990s, the development of the World-Wide Web increased the community of online fandom by of websites devoted to science fiction and related genres for all media. The first science fiction fanzine, The Comet, was published in 1930 by the Science Correspondence Club in Chicago, Illinois. One of the best known fanzines today is Ansible, edited by David Langford, winner of numerous Hugo awards. Other notable fanzines to win one or more Hugo awards include File 770, Mimosa, and Plokta. Artists working for fanzines have frequently risen to prominence in the field, including Brad W. Foster, Teddy Harvia, and Joe Mayhew; the Hugos include a category for Best Fan Artists. == Elements == Science fiction elements can include, among others: Temporal settings in the future, or in alternative histories; Predicted or speculative technology such as brain-computer interface, bio-engineering, superintelligent computers, robots, ray guns, and other advanced weapons; Space travel, settings in outer space, on other worlds, in subterranean earth, or in parallel universes; Fictional concepts in biology such as aliens, mutants, and enhanced humans; Undiscovered scientific possibilities such as teleportation, time travel, and faster-than-light travel or communication; New and different political and social systems and situations, including utopian, dystopian, post-apocalyptic, or post-scarcity; Future history and speculative evolution of humans on Earth or on other planets; Paranormal abilities such as mind control, telepathy, and telekinesis. == International examples == == Subgenres == == Related genres == == See also == == References == == General and cited sources == == External links == Science Fiction Bookshelf at Project Gutenberg Science fiction fanzines (current and historical) online SFWA "Suggested Reading" list Science fiction at standardebooks.org Science Fiction Research Association A selection of articles written by Mike Ashley, Iain Sinclair and others, exploring 19th-century visions of the future. Archived 18 June 2023 at the Wayback Machine from the British Library's Discovering Literature website. Merril Collection of Science Fiction, Speculation and Fantasy at Toronto Public Library Science Fiction Studies' Chronological Bibliography of Science Fiction History, Theory, and Criticism Best 50 sci-fi novels of all time (Esquire; 21 March 2022)
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Crime science is the study of crime in order to find ways to prevent it. It is distinguished from criminology in that it is focused on how crime is committed and how to reduce it, rather than on who committed it. It is multidisciplinary, notably recruiting scientific methodology rather than relying on social theory. == Definition == Crime science involves the application of scientific methodologies to prevent or reduce social disorder and find better ways to prevent, detect, and solve crimes. Crime science studies crime related events and how those events arise, or can be prevented, by attempting to understand the temptations and opportunities which provoke or allow offending, and which affect someone's choice to offend on a particular occasion, rather than assuming the problem is simply about bad people versus good people. It is a empirical approach often involving observational studies or quasi-experiments, as well as using randomised controlled trials, that seek to identify patterns of offending behaviour and factors that influence criminal offending behaviour and crime. The multi-disciplinary approach that involves practitioners from many fields including Policing, Geography, Urban Development, Mathematics, Statistics, Industrial Design, Construction Engineering, Physical Sciences, Medical Sciences, Economics, Computer Science, Psychology, Sociology, Criminology, Forensics, Law, and Public Management. == History == Crime science was conceived by the British broadcaster Nick Ross in the late 1990s (with encouragement from the then Commissioner of the Metropolitan Police, Sir John Stevens and Professor Ken Pease) out of concern that traditional criminology and orthodox political discourse were doing little to influence the ebb and flow of crime (e.g. Ross: Police Foundation Lecture, London, 11 July 2000 (jointly with Sir John Stevens); Parliamentary and Scientific Committee, 22 March 2001; Barlow Lecture, UCL, 6 April 2005). Ross described crime science as, "examining the chain of events that leads to crime in order to cut the weakest link" (Royal Institution Lecture 9 May 2002). == Jill Dando Institute of Crime Science == The first incarnation of crime science was the founding, also by Ross, of the Jill Dando Institute of Crime Science (JDI) at University College London in 2001. In order to reflect its broad disciplinary base, and its departure from the sociological (and often politicised) brand of criminology, the Institute is established in the Engineering Sciences Faculty, with growing ties to the physical sciences such as physics and chemistry but also drawing on the fields of statistics, environmental design, psychology, forensics, policing, economics and geography. The JDI grew rapidly and spawned a new Department of Security and Crime Science, which itself developed into one of the largest departments of its type in the world. It has established itself as a world-leader in crime mapping and for training crime analysts (civilian crime profilers who work for the police) and its Centre for the Forensic Sciences has been influential in debunking bad science in criminal detection. It established the world's first secure data lab for security and crime pattern analysis and appointed the world's first Professor of Future Crime whose role is to horizon-scan to foresee and forestall tomorrow's crime challenges. The JDI also developed a Security Science Doctoral Research Training Centre (UCL SECReT), which was Europe’s largest centre for doctoral training in security and crime science. == Design Against Crime Research Centre == Another branch of crime science has grown from its combination with design science. At the Central Saint Martins College of Arts and Design a research centre was founded with the focus of studying how design could be used as a tool against crime - the Design against Crime Research Centre. A number of practical theft-aware design practices have emerged there. Examples are chairs with a hanger that allows people to keep their bags within their reach for the whole time, or foldable bicycles that can serve as their own safety lock by wrapping around static poles in the environment. == International Crime Science Network == An international Crime Science Network was formed in 2003, with support from the EPSRC. Since then the term crime science has been variously interpreted, sometimes with a different emphasis from Ross's original description published in 1999, and often favouring situational crime prevention (redesigning products, services and policies to remove opportunities, temptations and provocations and make detection more certain) rather than other forms of intervention. However a common feature is a focus on delivering immediate reductions in crime. New crime science departments have been established at Waikato, Cincinnati, Philadelphia and elsewhere. == Growth of the Crime Science Field == The concept of crime science appears to be taking root more broadly with: The establishment of crime science departments at the University of Waikato in New Zealand, and University of Cincinnati in the US, and elsewhere. Crime Science courses at several institutions including Northumbria University in the UK, at the University of Twente in the Netherlands. and Temple University, Philadelphia in the US. A Crime Science Unit at DSTL, the research division of the UK Ministry of Defence. The term crime science increasingly being adopted by situational and experimental criminologists in the US and Australia. An annual Crime Science Network gathering in London which draws police and academics from across the world. A Springer Open Access Interdisciplinary journal devoted to Crime Science. Crime science increasingly being cited in criminology text books and journals papers (sometimes claimed as a new branch of criminology, and sometimes reviled as anti-criminology). A move in traditional criminology towards the aims originally set out by Ross in his concern for a more evidence-based, scientific approach to crime reduction. Crime science featuring in several learned journals in other disciplines (such as a special issue of the European Journal of Applied Mathematics devoted to "crime modelling"). == See also == Broken windows theory Parable of the broken window Crime prevention through environmental design Crime statistics Crime scene investigation Forensic science Evidence-based policing Intelligence-led policing Jill Dando Jill Dando Institute Community policing Peelian principles and Policing by consent Police science Predictive policing Preventive police Proactive policing Problem-oriented policing Recidivism == References == == Bibliography == Junger, Marianne; Laycock, Gloria; Hartel, Pieter; Ratcliffe, Jerry (11 June 2012). "Crime science: editorial statement". Crime Science. 1 (1): 1.1 – 1.3. doi:10.1186/2193-7680-1-1. ISSN 2193-7680. Hartel, Pieter H.; Junger, Marianne; Wieringa, Roelf J. (October 2010). "Cyber-crime Science = Crime Science + Information Security". CTIT Technical Report Series (Technical Report TR-CTIT-10-34). Enschede.: Centre for Telematics and Information Technology (CTIT), University of Twente. ISSN 1381-3625. Retrieved 21 January 2021. Pease, Ken (22 February 2010). "Crime science". In Shoham, Shlomo Giora; Knepper, Paul; Kett, Martin (eds.). International Handbook of Criminology (1 ed.). Boca Raton: Routledge. pp. 3–23. doi:10.1201/9781420085525. ISBN 978-0-429-25000-2. Retrieved 21 January 2021. Clarke, Ronald V. (31 March 2011). "Crime Science". In McLaughlin, Eugene; Newburn, Tim (eds.). The SAGE Handbook of Criminological Theory (Print, Online). SAGE Publications Ltd. pp. 271–283. doi:10.4135/9781446200926.n15. ISBN 978-1-4129-2038-4. Retrieved 22 January 2021. Guerette, Rob T.; Bowers, Kate J. (November 2009). "Assessing the Extent of Crime Displacement and Diffusion of Benefits: A Review of Situational Crime Prevention Evaluations*". Criminology. 47 (4): 1331–1368. doi:10.1111/j.1745-9125.2009.00177.x. ISSN 1745-9125. Retrieved 21 January 2021. Willison, Robert; Siponen, Mikko (1 September 2009). "Overcoming the insider: reducing employee computer crime through Situational Crime Prevention". Communications of the ACM. 52 (9): 133–137. doi:10.1145/1562164.1562198. ISSN 0001-0782. S2CID 2987733. Retrieved 21 January 2021. Cox, Karen (1 July 2008). "The application of crime science to the prevention of medication errors". British Journal of Nursing. 17 (14): 924–927. doi:10.12968/bjon.2008.17.14.30662. ISSN 0966-0461. PMID 18935846. Retrieved 21 January 2021. Tilley, Nick; Laycock, Gloria (2007). "From Crime Prevention to Crime Science". In Farrell, Graham; Bowers, Kate J.; Johnson, Shane D.; Townsley, Mike (eds.). Imagination for crime prevention : essays in honour of Ken Pease (Hardcover, Paperback). Monsey, New York: Criminal Justice Press. ISBN 978-1-881798-71-2. Retrieved 22 January 2021. Laycock, Gloria (2005). "Chapter 1: Defining Crime Science.". In Smith, Melissa J.; Tilley, Nick (eds.). Crime science: new approaches to preventing and detecting crime. Crime Science Series (1 ed.). Uffculme, UK: Willan Publishing. pp. 3–24. ISBN 1-843-92090-5. Clarke, Ronald V. (1997). "Part One: Introduction". In Clarke, Ronald V. (ed.). Situational Crime Prevention Successful Case Studies (PDF) (2 ed.). Guilderland, New York: Harrow and Heston. ISBN 0-911577-38-6. Archived from the original (PDF) on 26 June 2010. Retrieved 21 January 2021. == External links == Jill Dando Institute of Crime Science, U.K. Center for Problem-Oriented Policing, U.S.A. International Centre for the Prevention of Crime, CA Security Science Doctoral Research Training Centre New Zealand Institute for Security and Crime Science, N.Z. Cyber-crime Science
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Legal science is one of the main components in civil law tradition (after Roman law, canon law, commercial law, and the legacy of the revolutionary period). Legal science is primarily the creation of German legal scholars of the middle and late nineteenth century, and it evolved naturally out of the ideas of Friedrich Carl von Savigny. Savigny argued that German codification should not follow the rationalist and secular natural law thinking that characterized the French codification but should be based on the principles of law that had historically been in force in Germany. It is referred to as "Rechtswissenschaften" (plural) or "Rechtswissenschaft" (singular) in German. == See also == Legal theory == References == == Books == Black's Law Dictionary, Abridged Seventh Edition, Bryan A. Garner Sabino Cassese, Recensione a J.H. Merryman, “The Italian Style, Doctrine, Law, Interpretation”, in “Stanford Law Review”, 1965–66, in “Rivista trimestrale di diritto pubblico”, 1966, n. 2, pp. 419–424. == External links == The "Science" of Legal Science: The Model of the Natural Sciences in Nineteenth-Century American Legal Education
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Political science is the scientific study of politics. It is a social science dealing with systems of governance and power, and the analysis of political activities, political thought, political behavior, and associated constitutions and laws. Specialists in the field are political scientists. == History == === Origin === Political science is a social science dealing with systems of governance and power, and the analysis of political activities, political institutions, political thought and behavior, and associated constitutions and laws. As a social science, contemporary political science started to take shape in the latter half of the 19th century and began to separate itself from political philosophy and history. Into the late 19th century, it was still uncommon for political science to be considered a distinct field from history. The term "political science" was not always distinguished from political philosophy, and the modern discipline has a clear set of antecedents including moral philosophy, political economy, political theology, history, and other fields concerned with normative determinations of what ought to be and with deducing the characteristics and functions of the ideal state. Generally, classical political philosophy is primarily defined by a concern for Hellenic and Enlightenment thought, political scientists are also marked by a great concern for "modernity" and the contemporary nation state, along with the study of classical thought, and as such share more terminology with sociologists (e.g., structure and agency). The advent of political science as a university discipline was marked by the creation of university departments and chairs with the title of political science arising in the late 19th century. The designation "political scientist" is commonly used to denote someone with a doctorate or master's degree in the field. Integrating political studies of the past into a unified discipline is ongoing, and the history of political science has provided a rich field for the growth of both normative and positive political science, with each part of the discipline sharing some historical predecessors. The American Political Science Association and the American Political Science Review were founded in 1903 and 1906, respectively, in an effort to distinguish the study of politics from economics and other social phenomena. APSA membership rose from 204 in 1904 to 1,462 in 1915. APSA members played a key role in setting up political science departments that were distinct from history, philosophy, law, sociology, and economics.The journal Political Science Quarterly was established in 1886 by the Academy of Political Science. In the inaugural issue of Political Science Quarterly, Munroe Smith defined political science as "the science of the state. Taken in this sense, it includes the organization and functions of the state, and the relation of states one to another." As part of a UNESCO initiative to promote political science in the late 1940s, the International Political Science Association was founded in 1949, as well as national associations in France in 1949, Britain in 1950, and West Germany in 1951. === Behavioral revolution and new institutionalism === In the 1950s and the 1960s, a behavioral revolution stressing the systematic and rigorously scientific study of individual and group behavior swept the discipline. A focus on studying political behavior, rather than institutions or interpretation of legal texts, characterized early behavioral political science, including work by Robert Dahl, Philip Converse, and in the collaboration between sociologist Paul Lazarsfeld and public opinion scholar Bernard Berelson. The late 1960s and early 1970s witnessed a takeoff in the use of deductive, game-theoretic formal modelling techniques aimed at generating a more analytical corpus of knowledge in the discipline. This period saw a surge of research that borrowed theory and methods from economics to study political institutions, such as the United States Congress, as well as political behavior, such as voting. William H. Riker and his colleagues and students at the University of Rochester were the main proponents of this shift. Despite considerable research progress in the discipline based on all types of scholarship discussed above, scholars have noted that progress toward systematic theory has been modest and uneven. === 21st century === In 2000, the Perestroika Movement in political science was introduced as a reaction against what supporters of the movement called the mathematicization of political science. Those who identified with the movement argued for a plurality of methodologies and approaches in political science and for more relevance of the discipline to those outside of it. Some evolutionary psychology theories argue that humans have evolved a highly developed set of psychological mechanisms for dealing with politics. However, these mechanisms evolved for dealing with the small group politics that characterized the ancestral environment and not the much larger political structures in today's world. This is argued to explain many important features and systematic cognitive biases of current politics. == Overview == Political science is a social study concerning the allocation and transfer of power in decision making, the roles and systems of governance including governments and international organizations, political behaviour, and public policies. It measures the success of governance and specific policies by examining many factors, including stability, justice, material wealth, peace, and public health. Some political scientists seek to advance positive theses (which attempt to describe how things are, as opposed to how they should be) by analysing politics; others advance normative theses, such as by making specific policy recommendations. The study of politics and policies can be closely connected—for example, in comparative analyses of which types of political institutions tend to produce certain types of policies. Political science provides analysis and predictions about political and governmental issues. Political scientists examine the processes, systems and political dynamics of countries and regions of the world, often to raise public awareness or to influence specific governments. Political scientists may provide the frameworks from which journalists, special interest groups, politicians, and the electorate analyze issues. According to Chaturvedy, Political scientists may serve as advisers to specific politicians, or even run for office as politicians themselves. Political scientists can be found working in governments, in political parties, or as civil servants. They may be involved with non-governmental organizations (NGOs) or political movements. In a variety of capacities, people educated and trained in political science can add value and expertise to corporations. Private enterprises such as think tanks, research institutes, polling and public relations firms often employ political scientists. === Country-specific studies === Political scientists may study political phenomena within one specific country. For example, they may study just the politics of the United States or just the politics of China. Political scientists look at a variety of data, including constitutions, elections, public opinion, and public policy, foreign policy, legislatures, and judiciaries. Political scientists will often focus on the politics of their own country; for example, a political scientist from Indonesia may become an expert in the politics of Indonesia. === Anticipating crises === The theory of political transitions, and the methods of analyzing and anticipating crises, form an important part of political science. Several general indicators of crises and methods were proposed for anticipating critical transitions. Among them, one statistical indicator of crisis, a simultaneous increase of variance and correlations in large groups, was proposed for crisis anticipation and may be successfully used in various areas. Its applicability for early diagnosis of political crises was demonstrated by the analysis of the prolonged stress period preceding the 2014 Ukrainian economic and political crisis. There was a simultaneous increase in the total correlation between the 19 major public fears in the Ukrainian society (by about 64%) and in their statistical dispersion (by 29%) during the pre-crisis years. A feature shared by certain major revolutions is that they were not predicted. The theory of apparent inevitability of crises and revolutions was also developed. The study of major crises, both political crises and external crises that can affect politics, is not limited to attempts to predict regime transitions or major changes in political institutions. Political scientists also study how governments handle unexpected disasters, and how voters in democracies react to their governments' preparations for and responses to crises. == Research methods == Political science is methodologically diverse and appropriates many methods originating in psychology, social research, political philosophy, and many others, in addition to those that developed chiefly within the field of political science. Political scientists approach the study of politics from a host of different ontological orientations and with a variety of different tools. Because political science is essentially a study of human behavior, in all aspects of politics, observations in controlled environments are often challenging to reproduce or duplicate, though experimental methods are increasingly common (see experimental political science). Citing this difficulty, former American Political Science Association President Lawrence Lowell once said "We are limited by the impossibility of experiment. Politics is an observational, not an experimental science." Because of this, political scientists have historically observed political elites, institutions, and individual or group behaviour in order to identify patterns, draw generalizations, and build theories of politics. Like all social sciences, political science faces the difficulty of observing human actors that can only be partially observed and who have the capacity for making conscious choices, unlike other subjects, such as non-human organisms in biology, minerals in geoscience, chemical elements in chemistry, stars in astronomy, or particles in physics. Despite the complexities, contemporary political science has progressed by adopting a variety of methods and theoretical approaches to understanding politics, and methodological pluralism is a defining feature of contemporary political science. Empirical political science methods include the use of field experiments, surveys and survey experiments, case studies, process tracing, historical and institutional analysis, ethnography, participant observation, and interview research. Political scientists also use and develop theoretical tools like game theory and agent-based models to study a host of political systems and situations. Other approaches include the study of equation-based models and opinion dynamics. Political theorists approach theories of political phenomena with a similar diversity of positions and tools, including feminist political theory, historical analysis associated with the Cambridge school, and Straussian approaches. Political science may overlap with topics of study that are the traditional focuses of other social sciences—for example, when sociological norms or psychological biases are connected to political phenomena. In these cases, political science may either inherit their methods of study or develop a contrasting approach. For example, Lisa Wedeen has argued that political science's approach to the idea of culture, originating with Gabriel Almond and Sidney Verba and exemplified by authors like Samuel P. Huntington, could benefit from aligning more closely with the study of culture in anthropology. In turn, methodologies that are developed within political science may influence how researchers in other fields, like public health, conceive of and approach political processes and policies. The most common piece of academic writing in generalist political sciences is the research paper, which investigates an original research question. == Education == Political science, possibly like the social sciences as a whole, can be described "as a discipline which lives on the fault line between the 'two cultures' in the academy, the sciences and the humanities." Thus, in most American colleges, especially liberal arts colleges, it would be located within the school or college of arts and sciences. If no separate college of arts and sciences exists, or if the college or university prefers that it be in a separate constituent college or academic department, then political science may be a separate department housed as part of a division or school of humanities or liberal arts. At some universities, especially research universities and in particular those that have a strong cooperation between research, undergraduate, and graduate faculty with a stronger more applied emphasis in public administration, political science would be taught by the university's public policy school. Most United States colleges and universities offer BA programs in political science. MA or MAT and PhD or EdD programs are common at larger universities. The term political science is more popular in post-1960s North America than elsewhere while universities predating the 1960s or those historically influenced by them would call the field of study government; other institutions, especially those outside the United States, see political science as part of a broader discipline of political studies or politics in general. While political science implies the use of the scientific method, political studies implies a broader approach, although the naming of degree courses does not necessarily reflect their content. Separate, specialized or, in some cases, professional degree programs in international relations, public policy, and public administration are common at both the undergraduate and postgraduate levels, although most but not all undergraduate level education in these sub-fields of political science is generally found in academic concentrations within a political science academic major. Master's-level programs in public administration are professional degrees covering public policy along with other applied subjects; they are often seen as more linked to politics than any other discipline, which may be reflected by being housed in that department. The main national honor society for college and university students of government and politics in the United States is Pi Sigma Alpha, while Pi Alpha Alpha is a national honor society specifically designated for public administration. == See also == Artificial intelligence and elections – Use and impact of AI on political elections Comparative politics – Field in political science History of political science International relations – Study of relationships between two or more states Political history of the world Political identity – Type of social identity Political philosophy – Study of the foundations of politics === Lists === Index of politics articles Political lists Outline of political science – Overview of and topical guide to political science == References == == Further reading == == External links == IPSAPortal: Top 300 websites for Political Science Archived 27 February 2015 at the Wayback Machine Observatory of International Research (OOIR): Latest Papers and Trends in Political Science PROL: Political Science Research Online (prepublished research) === Professional organizations === European Consortium for Political Research Institute for Comparative Research in Human and Social Sciences (ICR) in Japan International Association for Political Science Students International Political Science Association International Studies Association Midwest Political Science Association Political Studies Association of the UK Southern Political Science Association === Library guides === Library. "Political Science". Research Guides. Michigan: University of Michigan. Archived from the original on 7 July 2014. Retrieved 15 February 2014. Bodleian Libraries. "Political Science". LibGuides. UK: University of Oxford. Archived from the original on 18 February 2014. Retrieved 15 February 2014. Library. "Politics Research Guide". LibGuides. New Jersey: Princeton University. Archived from the original on 23 July 2014. Retrieved 15 February 2014. Libraries. "Political Science". Research Guides. New York: Syracuse University. Archived from the original on 8 July 2014. Retrieved 15 February 2014. University Libraries. "Political Science". Research Guides. Texas: Texas A&M University. Archived from the original on 21 October 2014. Retrieved 15 February 2014.
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Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materials and methods to create, preserve, or duplicate images. Imaging science is a multidisciplinary field concerned with the generation, collection, duplication, analysis, modification, and visualization of images, including imaging things that the human eye cannot detect. As an evolving field it includes research and researchers from physics, mathematics, electrical engineering, computer vision, computer science, and perceptual psychology. Imagers are imaging sensors. == Imaging chain == The foundation of imaging science as a discipline is the "imaging chain" – a conceptual model describing all of the factors which must be considered when developing a system for creating visual renderings (images). In general, the links of the imaging chain include: The human visual system. Designers must also consider the psychophysical processes which take place in human beings as they make sense of information received through the visual system. The subject of the image. When developing an imaging system, designers must consider the observables associated with the subjects which will be imaged. These observables generally take the form of emitted or reflected energy, such as electromagnetic energy or mechanical energy. The capture device. Once the observables associated with the subject are characterized, designers can then identify and integrate the technologies needed to capture those observables. For example, in the case of consumer digital cameras, those technologies include optics for collecting energy in the visible portion of the electromagnetic spectrum, and electronic detectors for converting the electromagnetic energy into an electronic signal. The processor. For all digital imaging systems, the electronic signals produced by the capture device must be manipulated by an algorithm which formats the signals so they can be displayed as an image. In practice, there are often multiple processors involved in the creation of a digital image. The display. The display takes the electronic signals which have been manipulated by the processor and renders them on some visual medium. Examples include paper (for printed, or "hard copy" images), television, computer monitor, or projector. Note that some imaging scientists will include additional "links" in their description of the imaging chain. For example, some will include the "source" of the energy which "illuminates" or interacts with the subject of the image. Others will include storage and/or transmission systems. == Subfields == Subfields within imaging science include: image processing, computer vision, 3D computer graphics, animations, atmospheric optics, astronomical imaging, biological imaging, digital image restoration, digital imaging, color science, digital photography, holography, magnetic resonance imaging, medical imaging, microdensitometry, optics, photography, remote sensing, radar imaging, radiometry, silver halide, ultrasound imaging, photoacoustic imaging, thermal imaging, visual perception, and various printing technologies. == Methodologies == Acoustic imaging Coherent imaging uses an active coherent illumination source, such as in radar, synthetic aperture radar (SAR), medical ultrasound and optical coherence tomography; non-coherent imaging systems include fluorescent microscopes, optical microscopes, and telescopes. Chemical imaging, the simultaneous measurement of spectra and pictures Digital imaging, creating digital images, generally by scanning or through digital photography Disk image, a file which contains the exact content of a data storage medium Document imaging, replicating documents commonly used in business Geophysical imaging Industrial process imaging Medical imaging, creating images of the human body or parts of it, to diagnose or examine disease Medical optical imaging Magnetic resonance imaging Magneto-Acousto-Electrical Tomography (MAET), imaging modality to image the electrical conductivity of biological tissues Molecular imaging Radar imaging, or imaging radar, for obtaining an image of an object, not just its location and speed Range imaging, for obtaining images with depth information Reprography, reproduction of graphics through electrical and mechanical means Cinematography Photography, the process of creating still images Xerography, the method of photocopying Speckle imaging, a method of shift-and-add for astronomical imaging Stereo imaging, an aspect of sound recording and reproduction concerning spatial locations of the performers Thermography, infrared imaging Tactile imaging, also known as elastography == Examples == Imaging technology materials and methods include: Computer graphics Virtual camera system used in computer and video games and virtual cinematography Microfilm and Micrographics Visual arts Etching Drawing and Technical drawing Film Painting Photography Multiple-camera setup enables stereoscopy and stereophotogrammetry Light-field camera (basically refocusable photography) Printmaking Sculpture Infrared Radar imagery Ultrasound Multi-spectral image Electro-optical sensor Charge-coupled device Ground-penetrating radar Electron microscope Imagery analysis Medical radiography Industrial radiography LIDAR Image scanner Structured-light 3D scanner == See also == Image development (disambiguation) Image processing Nonimaging optics Society for Imaging Science and Technology The Imaging Science Journal == References == == Further reading == Harrison Hooker Barrett and Kyle J. Myers, Foundations of Image Science (John Wiley & Sons, 2004) ISBN 0471153001 Ronald N. Bracewell, Fourier Analysis and Imaging (Kluwer Academic, 2003) ISBN 0306481871 Roger L. Easton, Jr., Fourier Methods in Imaging (John Wiley & Sons, 2010) ISBN 9780470689837 DOI 10.1002/9780470660102 Robert D. Fiete, Modeling the Imaging Chain of Digital Cameras (SPIE Press, 2010) ISBN 9780819483393 == External links == Chester F. Carlson Center for Imaging Science at RIT Research center that offers B.S., M.S., and Ph.D. degrees in Imaging Science. The University of Arizona College of Optical Sciences offers an image science track for the M.S and Ph.D. degree in optical sciences. Science de l'image et des médias numériques Bachelor of image science and digital media unique in Canada. Image Sciences Institute, Utrecht, Netherlands Utrecht University Institute for Image Sciences - focuses on fundamental and applied research in specifically medical image processing and acquisition. Vanderbilt University Institute of Imaging Science - dedicated to using imaging to improve health-care and for advancing knowledge in the biological sciences.
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Science education is the teaching and learning of science to school children, college students, or adults within the general public. The field of science education includes work in science content, science process (the scientific method), some social science, and some teaching pedagogy. The standards for science education provide expectations for the development of understanding for students through the entire course of their K-12 education and beyond. The traditional subjects included in the standards are physical, life, earth, space, and human sciences. == Historical background == The first person credited with being employed as a science teacher in a British public school was William Sharp, who left the job at Rugby School in 1850 after establishing science to the curriculum. Sharp is said to have established a model for science to be taught throughout the British public school system. The British Association for the Advancement of Science (BAAS) published a report in 1867 calling for the teaching of "pure science" and training of the "scientific habit of mind." The progressive education movement supported the ideology of mental training through the sciences. BAAS emphasized separate pre-professional training in secondary science education. In this way, future BAAS members could be prepared. The initial development of science teaching was slowed by the lack of qualified teachers. One key development was the founding of the first London School Board in 1870, which discussed the school curriculum; another was the initiation of courses to supply the country with trained science teachers. In both cases the influence of Thomas Henry Huxley. John Tyndall was also influential in the teaching of physical science. In the United States, science education was a scatter of subjects prior to its standardization in the 1890s. The development of a science curriculum emerged gradually after extended debate between two ideologies, citizen science and pre-professional training. As a result of a conference of thirty leading secondary and college educators in Florida, the National Education Association appointed a Committee of Ten in 1892, which had authority to organize future meetings and appoint subject matter committees of the major subjects taught in secondary schools. The committee was composed of ten educators and chaired by Charles Eliot of Harvard University. The Committee of Ten appointed nine conferences committees: Latin; Greek; English; Other Modern Languages; Mathematics; History; Civil Government and Political Economy; physics, astronomy, and chemistry; natural history; and geography. Each committee was composed of ten leading specialists from colleges, normal schools, and secondary schools. Committee reports were submitted to the Committee of Ten, which met for four days in New York City, to create a comprehensive report. In 1894, the NEA published the results of the work of these conference committees. According to the Committee of Ten, the goal of high school was to prepare all students to do well in life, contributing to their well-being and the good of society. Another goal was to prepare some students to succeed in college. This committee supported the citizen science approach focused on mental training and withheld performance in science studies from consideration for college entrance. The BAAS encouraged their longer standing model in the UK. The US adopted a curriculum was characterized as follows: Elementary science should focus on simple natural phenomena (nature study) by means of experiments carried out "in-the-field." Secondary science should focus on laboratory work and the committee's prepared lists of specific experiments Teaching of facts and principles College preparation The format of shared mental training and pre-professional training consistently dominated the curriculum from its inception to now. However, the movement to incorporate a humanistic approach, such as inclusion of the arts (S.T.E.A.M.), science, technology, society and environment education is growing and being implemented more broadly in the late 20th century. Reports by the American Academy for the Advancement of Science (AAAS), including Project 2061, and by the National Committee on Science Education Standards and Assessment detail goals for science education that link classroom science to practical applications and societal implications. == Fields of science education == Science is a universal subject that spans the branch of knowledge that examines the structure and behavior of the physical and natural world through observation and experiment. Science education is most commonly broken down into the following three fields: Biology, chemistry, and physics. Additionally there is a large body of scientific literature that advocates the inclusion of teaching the Nature of Science, which is slowly being adopted into the national curricula. === Physics education === Physics education is characterized by the study of science that deals with matter and energy, and their interactions. Physics First, a program endorsed by the American Association of Physics Teachers, is a curriculum in which 9th grade students take an introductory physics course. The purpose is to enrich students' understanding of physics, and allow for more detail to be taught in subsequent high school biology and chemistry classes. It also aims to increase the number of students who go on to take 12th grade physics or AP Physics, which are generally elective courses in American high schools.[22] Physics education in high schools in the United States has suffered the last twenty years because many states now only require three sciences, which can be satisfied by earth/physical science, chemistry, and biology. The fact that many students do not take physics in high school makes it more difficult for those students to take scientific courses in college. At the university/college level, using appropriate technology-related projects to spark non-physics majors' interest in learning physics has been shown to be successful.[23] This is a potential opportunity to forge the connection between physics and social benefit. === Chemistry education === Chemistry education is characterized by the study of science that deals with the composition, structure, and properties of substances and the transformations that they undergo. Chemistry is the study of chemicals and the elements and their effects and attributes. Students in chemistry learn the periodic table. The branch of science education known as "chemistry must be taught in a relevant context in order to promote full understanding of current sustainability issues." As this source states chemistry is a very important subject in school as it teaches students to understand issues in the world. As children are interested by the world around them chemistry teachers can attract interest in turn educating the students further. The subject of chemistry is a very practical based subject meaning most of class time is spent working or completing experiments. === Biology education === Biology education is characterized by the study of structure, function, heredity, and evolution of all living organisms. Biology itself is the study of living organisms, through different fields including morphology, physiology, anatomy, behavior, origin, and distribution. Depending on the country and education level, there are many approaches to teaching biology. In the United States, there is a growing emphasis on the ability to investigate and analyze biology related questions over an extended period of time. Current biological education standards are based on decisions made by the Committee of Ten, who aimed to standardize pre-college learning in 1892. The Committee emphasized the importance of learning natural history (biology) first, focusing on observation through laboratory work. === Nature of Science education === Nature of Science education refers to the study of how science is a human initiative, how it interacts with society, what scientists do, how scientific knowledge is built up and exchanged, how it evolves, how it is used. It stresses the empirical nature and the different methods used in science. The goals of Nature of Science education are stated to be to help students evaluate scientific and pseudo scientific statements, to motivate them to study science and to better prepare them for a career in science or in a field that interacts with science. == Pedagogy == While the public image of science education may be one of simply learning facts by rote, science education in recent history also generally concentrates on the teaching of science concepts and addressing misconceptions that learners may hold regarding science concepts or other content. Thomas Kuhn, whose 1962 book The Structure of Scientific Revolutions greatly influenced the post-positivist philosophy of science, argued that the traditional method of teaching in the natural sciences tends to produce a rigid mindset. Since the 1980s, science education has been strongly influenced by constructivist thinking. Constructivism in science education has been informed by an extensive research programme into student thinking and learning in science, and in particular exploring how teachers can facilitate conceptual change towards canonical scientific thinking. Constructivism emphasises the active role of the learner, and the significance of current knowledge and understanding in mediating learning, and the importance of teaching that provides an optimal level of guidance to learners. According to a 2004 Policy Forum in Science magazine, "scientific teaching involves active learning strategies to engage students in the process of science and teaching methods that have been systematically tested and shown to reach diverse students." The 2007 volume Scientific Teaching lists three major tenets of scientific teaching: Active learning: A process in which students are actively engaged in learning. It may include inquiry-based learning, cooperative learning, or student-centered learning. Assessment: Tools for measuring progress toward and achievement of the learning goals. Diversity: The breadth of differences that make each student unique, each cohort of students unique, and each teaching experience unique. Diversity includes everything in the classroom: the students, the instructors, the content, the teaching methods, and the context. These elements should underlie educational and pedagogical decisions in the classroom. The "SCALE-UP" learning environment is an example of applying the scientific teaching approach. In practice, scientific teaching employs a "backward design" approach. The instructor first decides what the students should know and be able to do (learning goals), then determines what would be evidence of student achievement of the learning goals, then designs assessments to measure this achievement. Finally, the instructor plans the learning activities, which should facilitate student learning through scientific discovery. === Guided-discovery approach === Along with John Dewey, Jerome Bruner, and many others, Arthur Koestler offers a critique of contemporary science education and proposes its replacement with the guided-discovery approach: To derive pleasure from the art of discovery, as from the other arts, the consumer—in this case the student—must be made to re-live, to some extent, the creative process. In other words, he must be induced, with proper aid and guidance, to make some of the fundamental discoveries of science by himself, to experience in his own mind some of those flashes of insight which have lightened its path. . . . The traditional method of confronting the student not with the problem but with the finished solution, means depriving him of all excitement, [shutting] off the creative impulse, [reducing] the adventure of mankind to a dusty heap of theorems.Specific hands-on illustrations of this approach are available. == Research == The practice of science education has been increasingly informed by research into science teaching and learning. Research in science education relies on a wide variety of methodologies, borrowed from many branches of science and engineering such as computer science, cognitive science, cognitive psychology and anthropology. Science education research aims to define or characterize what constitutes learning in science and how it is brought about. John D. Bransford, et al., summarized massive research into student thinking as having three key findings: Preconceptions Prior ideas about how things work are remarkably tenacious and an educator must explicitly address a students' specific misconceptions if the student is to reconfigure his misconception in favour of another explanation. Therefore, it is essential that educators know how to learn about student preconceptions and make this a regular part of their planning. Knowledge organization In order to become truly literate in an area of science, students must, "(a) have a deep foundation of factual knowledge, (b) understand facts and ideas in the context of a conceptual framework, and (c) organize knowledge in ways that facilitate retrieval and application." Metacognition Students will benefit from thinking about their thinking and their learning. They must be taught ways of evaluating their knowledge and what they do not know, evaluating their methods of thinking, and evaluating their conclusions. Some educators and others have practiced and advocated for discussions of pseudoscience as a way to understand what it is to think scientifically and to address the problems introduced by pseudoscience. Educational technologies are being refined to meet the specific needs of science teachers. One research study examining how cellphones are being used in post-secondary science teaching settings showed that mobile technologies can increase student engagement and motivation in the science classroom. According to a bibliography on constructivist-oriented research on teaching and learning science in 2005, about 64 percent of studies documented are carried out in the domain of physics, 21 percent in the domain of biology, and 15 percent in chemistry. The major reason for this dominance of physics in the research on teaching and learning appears to be that understanding physics includes difficulties due to the particular nature of physics. Research on students' conceptions has shown that most pre-instructional (everyday) ideas that students bring to physics instruction are in stark contrast to the physics concepts and principles to be achieved – from kindergarten to the tertiary level. Quite often students' ideas are incompatible with physics views. This also holds true for students' more general patterns of thinking and reasoning. == By country == === Australia === As in England and Wales, science education in Australia is compulsory up until year 11, where students can choose to study one or more of the branches mentioned above. If they wish to no longer study science, they can choose none of the branches. The science stream is one course up until year 11, meaning students learn in all of the branches giving them a broad idea of what science is all about. The National Curriculum Board of Australia (2009) stated that "The science curriculum will be organised around three interrelated strands: science understanding; science inquiry skills; and science as a human endeavour." These strands give teachers and educators the framework of how they should be instructing their students. In 2011, it was reported that a major problem that has befallen science education in Australia over the last decade is a falling interest in science. Fewer year 10 students are choosing to study science for year 11, which is problematic as these are the years where students form attitudes to pursue science careers. This issue is not unique in Australia, but is happening in countries all over the world. === China === Educational quality in China suffers because a typical classroom contains 50 to 70 students. With over 200 million students, China has the largest educational system in the world. However, only 20% percent of students complete the rigorous ten-year program of formal schooling. As in many other countries, the science curriculum includes sequenced courses in physics, chemistry, and biology. Science education is given high priority and is driven by textbooks composed by committees of scientists and teachers. Science education in China places great emphasis on memorization, and gives far less attention to problem solving, application of principles to novel situations, interpretations, and predictions. === United Kingdom === In English and Welsh schools, science is a compulsory subject in the National Curriculum. All pupils from 5 to 16 years of age must study science. It is generally taught as a single subject science until sixth form, then splits into subject-specific A levels (physics, chemistry and biology). However, the government has since expressed its desire that those pupils who achieve well at the age of 14 should be offered the opportunity to study the three separate sciences from September 2008. In Scotland the subjects split into chemistry, physics and biology at the age of 13–15 for National 4/5s in these subjects, and there is also a combined science standard grade qualification which students can sit, provided their school offers it. In September 2006 a new science program of study known as 21st Century Science was introduced as a GCSE option in UK schools, designed to "give all 14 to 16-year-old's a worthwhile and inspiring experience of science". In November 2013, Ofsted's survey of science in schools revealed that practical science teaching was not considered important enough. At the majority of English schools, students have the opportunity to study a separate science program as part of their GCSEs, which results in them taking 6 papers at the end of Year 11; this usually fills one of their option 'blocks' and requires more science lessons than those who choose not to partake in separate science or are not invited. Other students who choose not to follow the compulsory additional science course, which results in them taking 4 papers resulting in 2 GCSEs, opposed to the 3 GCSEs given by taking separate science. === United States === In many U.S. states, K-12 educators must adhere to rigid standards or frameworks of what content is to be taught to which age groups. This often leads teachers to rush to "cover" the material, without truly "teaching" it. In addition, the process of science, including such elements as the scientific method and critical thinking, is often overlooked. This emphasis can produce students who pass standardized tests without having developed complex problem solving skills. Although at the college level American science education tends to be less regulated, it is actually more rigorous, with teachers and professors fitting more content into the same time period. In 1996, the U.S. National Academy of Sciences of the U.S. National Academies produced the National Science Education Standards, which is available online for free in multiple forms. Its focus on inquiry-based science, based on the theory of constructivism rather than on direct instruction of facts and methods, remains controversial. Some research suggests that it is more effective as a model for teaching science. "The Standards call for more than 'science as process,' in which students learn such skills as observing, inferring, and experimenting. Inquiry is central to science learning. When engaging in inquiry, students describe objects and events, ask questions, construct explanations, test those explanations against current scientific knowledge, and communicate their ideas to others. They identify their assumptions, use critical and logical thinking, and consider alternative explanations. In this way, students actively develop their understanding of science by combining scientific knowledge with reasoning and thinking skills."Concern about science education and science standards has often been driven by worries that American students, and even teachers, lag behind their peers in international rankings. One notable example was the wave of education reforms implemented after the Soviet Union launched its Sputnik satellite in 1957. The first and most prominent of these reforms was led by the Physical Science Study Committee at MIT. In recent years, business leaders such as Microsoft Chairman Bill Gates have called for more emphasis on science education, saying the United States risks losing its economic edge. To this end, Tapping America's Potential is an organization aimed at getting more students to graduate with science, technology, engineering and mathematics degrees. Public opinion surveys, however, indicate most U.S. parents are complacent about science education and that their level of concern has actually declined in recent years. Furthermore, in the recent National Curriculum Survey conducted by ACT, researchers uncovered a possible disconnect among science educators. "Both middle school/junior high school teachers and post secondary science instructors rate(d) process/inquiry skills as more important than advanced science content topics; high school teachers rate them in exactly the opposite order." Perhaps more communication among educators at the different grade levels in necessary to ensure common goals for students. ==== 2012 science education framework ==== According to a report from the National Academy of Sciences, the fields of science, technology, and education hold a paramount place in the modern world, but there are not enough workers in the United States entering the science, technology, engineering, and math (STEM) professions. In 2012 the National Academy of Sciences Committee on a Conceptual Framework for New K-12 Science Education Standards developed a guiding framework to standardize K-12 science education with the goal of organizing science education systematically across the K-12 years. Titled A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas, the publication promotes standardizing K-12 science education in the United States. It emphasizes science educators to focus on a "limited number of disciplinary core ideas and crosscutting concepts, be designed so that students continually build on and revise their knowledge and abilities over multiple years, and support the integration of such knowledge and abilities with the practices needed to engage in scientific inquiry and engineering design." The report says that in the 21st century Americans need science education in order to engage in and "systematically investigate issues related to their personal and community priorities," as well as to reason scientifically and know how to apply science knowledge. The committee that designed this new framework sees this imperative as a matter of educational equity to the diverse set of schoolchildren. Getting more diverse students into STEM education is a matter of social justice as seen by the committee. ==== 2013 Next Generation Science Standards ==== In 2013 a new standards for science education were released that update the national standards released in 1996. Developed by 26 state governments and national organizations of scientists and science teachers, the guidelines, called the Next Generation Science Standards, are intended to "combat widespread scientific ignorance, to standardize teaching among states, and to raise the number of high school graduates who choose scientific and technical majors in college...." Included are guidelines for teaching students about topics such as climate change and evolution. An emphasis is teaching the scientific process so that students have a better understanding of the methods of science and can critically evaluate scientific evidence. Organizations that contributed to developing the standards include the National Science Teachers Association, the American Association for the Advancement of Science, the National Research Council, and Achieve, a nonprofit organization that was also involved in developing math and English standards. ==== Next Generation Science Standards ==== Science education curriculum in the United States is outlined by the Next Generation Science Standards (NGSS) which were released in April 2013. The purpose of the NGSS is to establish a standardized Kindergarten to 12th Grade science curriculum. These standards were instituted in hopes that they would reform the past science education system, and foster higher student achievement through improved curriculum and teacher development. The Next Generation Science Standards are made up of three components listed as follows: disciplinary core ideas, science and engineering practices, and crosscutting concepts. These are referred to as the three dimensions of the Next Generation Science Standards. Within these standards, there is emphasis on alignment with K-12 Common Core state standards. The dimension entitled "science and engineering practices" focuses on students' learning of the scientific method. This means that this dimension centers around practicing science in a hands-on manner, giving students the opportunity to observe scientific processes, hypothesize, and observe results. This dimension highlights the empirical methods of science. The dimension entitled "crosscutting concepts" emphasizes the understanding of key themes within the field of science. The "crosscutting concepts" are themes that are consistently relevant throughout many different scientific disciplines, such as the flow of energy/matter, cause/effect, systems/system practices, patterns, the relationship between structure and function, and stability/change. The purpose of outlining these key themes relates to generalized learning, meaning that the effectiveness of these themes could lie in the fact that these concepts are important throughout all of the scientific disciplines. The intention is that by learning them, students will create a broad understanding of science. The dimension entitled "disciplinary core ideas" outlines a set of key ideas for each scientific field. For example, physical science has a certain set of core ideas laid out by the framework. ==== Science Education and Common Core ==== Common Core education standards emphasize on reading, writing, and communication skills. The purpose of these standards for English and Mathematics was to create measurable goals for student learning that are aligned with the standards in place in other nations, such that students in the United States become prepared to succeed at a global level. It is meant to set standards for academics that are rigorous in nature and prepare students for higher education. It is also outlined that students with disabilities must be properly accommodated for under Common Core standards via an Individualized Education Plan (IEP). Under these standards, the comprehension of scientific writing has become an important skill for students to learn through textbooks. ==== Science Education Strategies ==== Evidence suggests, however, that students learn science more effectively under hands-on, activity and inquiry based learning, rather than learning from a textbook. It has been seen that students, in particular those with learning disabilities, perform better on unit tests after learning science through activities, rather than textbook-based learning. Thus, it is argued that science is better learned through experiential activities. Additionally, it has reported that students, specifically those with learning disabilities, prefer and feel that they learn more effectively through activity-based learning. Information like this can help inform the way science is taught and how it can be taught most effectively for students of all abilities. The laboratory is a foundational example of hands-on, activity-based learning. In the laboratory, students use materials to observe scientific concepts and phenomena. The laboratory in science education can include multiple different phases. These phases include planning and design, performance, and analysis and interpretation. It is believed by many educators that laboratory work promotes their students' scientific thinking, problem solving skills, and cognitive development. Since 1960, instructional strategies for science education have taken into account Jean Piaget's developmental model, and therefore started introducing concrete materials and laboratory settings, which required students to actively participate in their learning. In addition to the importance of the laboratory in learning and teaching science, there has been an increase in the importance of learning using computational tools. The use of computational tools, which have become extremely prevalent in STEM fields as a result of the advancement of technology, has been shown to support science learning. The learning of computational science in the classroom is becoming foundational to students' learning of modern science concepts. In fact, the Next Generation Science Standards specifically reference the use of computational tools and simulations. Through the use of computational tools, students participate in computational thinking, a cognitive process in which interacting with computational tools such as computers is a key aspect. As computational thinking becomes increasingly relevant in science, it becomes an increasingly important aspect of learning for science educators to act on. Another strategy, that may include both hands-on activities and using computational tools, is creating authentic science learning experiences. Several perspectives of authentic science education have been suggested, including: canonical perspective - making science education as similar as possible to the way science is practiced in the real world; youth-centered - solving problems that are of interest to young students; contextual - a combination of the canonical and youth-centered perspectives. Although activities involving hands-on inquiry and computational tools may be authentic, some have contended that inquiry tasks commonly used in schools are not authentic enough, but often rely on simple "cookbook" experiments. Authentic science learning experiences can be implemented in various forms. For example: hand on inquiry, preferably involving an open ended investigation; student-teacher-scientist partnership (STSP) or citizen science projects; design-based learning (DBL); using web-based environments used by scientists (using bioinformatics tools like genes or proteins databases, alignment tools etc.), and; learning with adapted primary literature (APL), which exposes students also to the way the scientific community communicates knowledge. These examples and more can be applied to various domains of science taught in schools (as well as undergraduate education), and comply with the calls to include scientific practices in science curricula. ==== Informal science education ==== Informal science education is the science teaching and learning that occurs outside of the formal school curriculum in places such as museums, the media, and community-based programs. The National Science Teachers Association has created a position statement on Informal Science Education to define and encourage science learning in many contexts and throughout the lifespan. Research in informal science education is funded in the United States by the National Science Foundation. The Center for Advancement of Informal Science Education (CAISE) provides resources for the informal science education community. Examples of informal science education include science centers, science museums, and new digital learning environments (e.g. Global Challenge Award), many of which are members of the Association of Science and Technology Centers (ASTC). The Franklin Institute in Philadelphia and the Museum of Science (Boston) are the oldest of this type of museum in the United States. Media include TV programs such as NOVA, Newton's Apple, "Bill Nye the Science Guy","Beakman's World", The Magic School Bus, and Dragonfly TV. Early examples of science education on American television included programs by Daniel Q. Posin, such as "Dr. Posin's Universe", "The Universe Around Us", "On the Shoulders of Giants", and "Out of This World". Examples of community-based programs are 4-H Youth Development programs, Hands On Science Outreach, NASA and After school Programs and Girls at the Center. Home education is encouraged through educational products such as the former (1940-1989) Things of Science subscription service. In 2010, the National Academies released Surrounded by Science: Learning Science in Informal Environments, based on the National Research Council study, Learning Science in Informal Environments: People, Places, and Pursuits. Surrounded by Science is a resource book that shows how current research on learning science across informal science settings can guide the thinking, the work, and the discussions among informal science practitioners. This book makes valuable research accessible to those working in informal science: educators, museum professionals, university faculty, youth leaders, media specialists, publishers, broadcast journalists, and many others. == See also == Center for Informal Learning and Schools Controversial science Constructivism in science education Discipline-based education research Discovery learning Educational research Environmental groups and resources serving K–12 schools Epistemology (the study of knowledge and how we know things) Graduate school Inquiry-based Science National Science Education Standards National Science Teachers Association Pedagogy Physics education Mathematics education Engineering education Public awareness of science School science technicians Science education in England Science, Technology, Society and Environment Education Scientific literacy Science outreach Scientific modelling Science education on YouTube == References == == Further reading == "Is science only for the rich?". Nature. 537 (7621): 466–470. 2016. Bibcode:2016Natur.537..466.. doi:10.1038/537466a. PMID 27652548. S2CID 205090336. Aikenhead, G.S. (1994). "What is STS teaching?". In Solomon, J.; Aikenhead, G.S. (eds.). STS education: International perspectives on reform. New York: Teachers College Press. pp. 74–59. ISBN 978-0807733653. Dumitru, P.; Joyce, A. (2007). "Public-private partnerships for maths, science and technology education" (PDF). Proceedings of Discovery Days conference. "National and European Initiatives to promote science education in Europe" (PDF). European Schoolnet. 2007. Shamos, Morris Herbert (1995). The Myth of Scientific Literacy. Rutgers University Press. ISBN 978-0-8135-2196-1. Berube, Clair T. (2008). The Unfinished Quest: The Plight of Progressive Science Education in the Age of Standards. Charlotte NC: Information Age. ISBN 978-1-59311-928-7. Falk, John H. (2001). Science Education: How We Learn Science Outside of School. New York: Teachers College. ISBN 978-0-8077-4064-4. Sheppard, K.; Robbins D.M. (2007). "High School Biology Today: What the Committee of Ten Actually Said". CBE: Life Sciences Education. 6 (3): 198–202. doi:10.1187/cbe.07-03-0013. PMC 1964524. PMID 17785402. == External links == The Association for Science Teacher Education Eurasia Journal of Mathematics, Science & Technology Education The European Learning Laboratory for the Life Sciences (ELLS) CBE Life Science Education interview with Jo Handlesman (2009) Science Education Forum by Miller et al. (2008)
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Applied science is the application of the scientific method and scientific knowledge to attain practical goals. It includes a broad range of disciplines, such as engineering and medicine. Applied science is often contrasted with basic science, which is focused on advancing scientific theories and laws that explain and predict natural or other phenomena. There are applied natural sciences, as well as applied formal and social sciences. Applied science examples include genetic epidemiology which applies statistics and probability theory, and applied psychology, including criminology. == Applied research == Applied research is the use of empirical methods to collect data for practical purposes. It accesses and uses accumulated theories, knowledge, methods, and techniques for a specific state, business, or client-driven purpose. In contrast to engineering, applied research does not include analyses or optimization of business, economics, and costs. Applied research can be better understood in any area when contrasting it with basic or pure research. Basic geographical research strives to create new theories and methods that aid in explaining the processes that shape the spatial structure of physical or human environments. Instead, applied research utilizes existing geographical theories and methods to comprehend and address particular empirical issues. Applied research usually has specific commercial objectives related to products, procedures, or services. The comparison of pure research and applied research provides a basic framework and direction for businesses to follow. Applied research deals with solving practical problems and generally employs empirical methodologies. Because applied research resides in the messy real world, strict research protocols may need to be relaxed. For example, it may be impossible to use a random sample. Thus, transparency in the methodology is crucial. Implications for the interpretation of results brought about by relaxing an otherwise strict canon of methodology should also be considered. Moreover, this type of research method applies natural sciences to human conditions: Action research: aids firms in identifying workable solutions to issues influencing them. Evaluation research: researchers examine available data to assist clients in making wise judgments. Industrial research: create new goods/services that will satisfy the demands of a target market. (Industrial development would be scaling up production of the new goods/services for mass consumption to satisfy the economic demand of the customers while maximizing the ratio of the good/service output rate to resource input rate, the ratio of good/service revenue to material & energy costs, and the good/service quality. Industrial development would be considered engineering. Industrial development would fall outside the scope of applied research.) Gauging research: A type of evaluation research that uses a logic of rating to assess a process or program. It is a type of normative assessment and used in accreditation, hiring decisions and process evaluation. It uses standards or the practical ideal type and is associated with deductive qualitative research. Since applied research has a provisional close-to-the-problem and close-to-the-data orientation, it may also use a more provisional conceptual framework, such as working hypotheses or pillar questions. The OECD's Frascati Manual describes applied research as one of the three forms of research, along with basic research & experimental development. Due to its practical focus, applied research information will be found in the literature associated with individual disciplines. == Branches == Applied research is a method of problem-solving and is also practical in areas of science, such as its presence in applied psychology. Applied psychology uses human behavior to grab information to locate a main focus in an area that can contribute to finding a resolution. More specifically, this study is applied in the area of criminal psychology. With the knowledge obtained from applied research, studies are conducted on criminals alongside their behavior to apprehend them. Moreover, the research extends to criminal investigations. Under this category, research methods demonstrate an understanding of the scientific method and social research designs used in criminological research. These reach more branches along the procedure towards the investigations, alongside laws, policy, and criminological theory. Engineering is the practice of using natural science, mathematics, and the engineering design process to solve technical problems, increase efficiency and productivity, and improve systems. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. Engineering is often characterized as having four main branches: chemical engineering, civil engineering, electrical engineering, and mechanical engineering. Some scientific subfields used by engineers include thermodynamics, heat transfer, fluid mechanics, statics, dynamics, mechanics of materials, kinematics, electromagnetism, materials science, earth sciences, and engineering physics. Medical sciences, such as medical microbiology, pharmaceutical research, and clinical virology, are applied sciences that apply biology and chemistry to medicine. == In education == In Canada, the Netherlands, and other places, the Bachelor of Applied Science (BASc) is sometimes equivalent to the Bachelor of Engineering and is classified as a professional degree. This is based on the age of the school where applied science used to include boiler making, surveying, and engineering. There are also Bachelor of Applied Science degrees in Child Studies. The BASc tends to focus more on the application of the engineering sciences. In Australia and New Zealand, this degree is awarded in various fields of study and is considered a highly specialized professional degree. In the United Kingdom's educational system, Applied Science refers to a suite of "vocational" science qualifications that run alongside "traditional" General Certificate of Secondary Education or A-Level Sciences. Applied Science courses generally contain more coursework (also known as portfolio or internally assessed work) compared to their traditional counterparts. These are an evolution of the GNVQ qualifications offered up to 2005. These courses regularly come under scrutiny and are due for review following the Wolf Report 2011; however, their merits are argued elsewhere. In the United States, The College of William & Mary offers an undergraduate minor as well as Master of Science and Doctor of Philosophy degrees in "applied science". Courses and research cover varied fields, including neuroscience, optics, materials science and engineering, nondestructive testing, and nuclear magnetic resonance. University of Nebraska–Lincoln offers a Bachelor of Science in applied science, an online completion Bachelor of Science in applied science, and a Master of Applied Science. Coursework is centered on science, agriculture, and natural resources with a wide range of options, including ecology, food genetics, entrepreneurship, economics, policy, animal science, and plant science. In New York City, the Bloomberg administration awarded the consortium of Cornell-Technion $100 million in City capital to construct the universities' proposed Applied Sciences campus on Roosevelt Island. == See also == Applied mathematics Basic research Exact sciences Hard and soft science Invention Secondary research == References == == External links == Media related to Applied sciences at Wikimedia Commons
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The Science in Science Fiction is a book by David Langford, Peter Nicholls and Brian Stableford published in 1982. The book is divided into twelve chapters. The first eleven chapters each examine science fiction works about a particular topic, such as Space Flight, Aliens or Time Travel, and discuss how accurate the works are to real science; the final chapter of the book covers notable instances "where science fiction gets it wrong". == Reception == Dave Pringle, the former editor of Foundation and Interzone, reviewed the book for Imagine magazine in April 1983, describing it as "an excellent and timely work of non-fiction," and stated he hopes "every would-be SF writer in the land reads this book and comes to the realisation that raw imagination and an ability with words are not enough; a modicum of knowledge has always been necessary to the creation of worthwhile science-fiction." Science fiction author Gene DeWeese reviewed the book for Science Fiction Review in May 1983, recommending the book to any science fiction reader who wants to know if the events depicted could actually happen. His review was mostly positive, particularly complimenting the book's "clear and interesting prose" and its illustrations, although he criticized David Langford for coming across as condescending and "fail[ing] to distinguish between authors who made silly mistakes because of ignorance and those who purposely violated current scientific theories." The book was also reviewed by Gregory Benford in issue #267 of Locus in April 1983 Review by Patrick Parrinder (1983) in Science Fiction & Fantasy Book Review, #11, January-February 1983 Review by Neil Barron (1983) in Science Fiction & Fantasy Book Review, #11, January-February 1983 Review by Ken Methold (1983) in Omega Science Digest, September-October 1983 Review by Duncan Lunan (1983) in The Bulletin of the Science Fiction Writers of America, Fall 1983 Review [German] by Uwe Anton (1984) in Science Fiction Times, Januar 1984 Review by Andrew C. Murdoch (1993) in ZX, July-August 1993 == References ==
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A Doctor of Science (Latin: Scientiae Doctor; most commonly abbreviated DSc or ScD) is a science doctorate awarded in a number of countries throughout the world. == Africa == === Algeria and Morocco === In Algeria, Morocco, Libya and Tunisia, all universities accredited by the state award a "Doctorate" in all fields of science and humanities, equivalent to a PhD in the United Kingdom or United States. Some universities in these four North African countries award a "Doctorate of the State" in some fields of study and science. A "Doctorate of the State" is slightly higher in esteem than a regular doctorate, and is awarded after performing additional in-depth post-doctorate research or achievement. == Asia == === Japan === Similarly to in the US and most of Europe, Japanese universities offer both the PhD and the ScD as initial doctorates in science. === India === In India only a few prestigious universities offer ScD/DSc in science which is obtained in Graduate School after satisfactory evaluation of knowledge, research accomplishment, and a doctoral defence. The oldest institute to award a DSc degree in India is Rajabazar Science College, University of Calcutta. === Thailand === Higher education institutes in Thailand generally grant PhD as a doctoral research degree, some universities including Chulalongkorn University award DSc. In exception, Mahidol University can grant both PhD and DSc. Doctoral students in Faculty of Science are always awarded PhD, but some other programs award DSc. === Uzbekistan === DSc or PhD degrees are awarded after dissertation and fulfilling the required publication number. In order to qualify for DSc, one is required to have attained a PhD. The higher education institutes in Uzbekistan also grant DSc degrees. As an example, the National University of Uzbekistan and the Uzbekistan Academy of Sciences offer DSc in various fields. == Europe == === Austria, Germany, and Switzerland === In Germany, Austria, and the German-speaking region of Switzerland, common doctoral degrees in science are the following: Dr. techn.: Doctor technicae, awarded by Austrian technical universities. In German: "Doktor der technischen Wissenschaften" which translates to Doctor of Engineering Sciences, or Doctor of Science, or Doctor of Technical Sciences, or Doctor of Technology. Dr.techn. title is also awarded in Denmark. Dr. rer. nat.: Doctor rerum naturalium, literally "Doctor of the things of nature" Dr. rer. medic.: Doctor rerum medicarum, Doctor of medical sciences Dr. sc. med.: Doctor scientiarum medicarum, Doctor of science in medicine Dr. sc. nat.: Doktor der Naturwissenschaften, Doctor of Natural Sciences Dr. sc. ETH: Doktor der Naturwissenschaften ETH, Doctor of Natural Sciences, awarded by ETH Zurich, Switzerland. Dr. phil. nat.: Doctor philosophiae naturalis, used only by Goethe University Frankfurt instead of Dr rer. nat; Doctor of Natural Sciences, awarded by Swiss universities. Dr.-Ing.: Doktor der Ingenieurwissenschaften (Doctor of Engineering), awarded by German universities in areas of technology and engineering. Dr. mont.: Doctor rerum montanarum, awarded by the University of Leoben instead of Dr. techn. Dr. nat. techn.: Doctor rerum naturalium technicarum, awarded by the University of Natural Resources and Life Sciences, Vienna instead of Dr. techn. In these countries there are some related doctoral degrees with very similar names, these are the: Dr. sc. agr.: Doctor scientiarum agrariarum, Doctor of Agricultural science Dr. sc. hum.: Doctor scientiarum humanarum, Doctor of Humanistic Sciences Dr. sc. inf.: Doctor scientiarum informaticarum, Doctor of Science in Informatics Dr. sc. inf. med.: Doctor scientiarum informaticarum medicæ, Doctor of Science in Medical Informatics Dr. sc. inf. biomed.: Doctor scientiarum informaticarum biomedicæ, Doctor of Science in Biomedical Informatics Dr. sc. math.: Doctor scientiarum mathematicarum, Doctor of Mathematics Dr. scient. med.: Doctor scientiæ medicæ, Doctor of Medical Sciences Dr. sc. mus.: Doctor scientiae musicae, Doctor of Musicology Dr. sc. oec.: Doctor scientiarum oeconomicarum, Doctor of Economics Dr. sc. pol.: Doctor scientiarum politicarum, Doctor of Political Sciences Dr. rer. pol.: Doctor rerum politicarum, Doctor of economics, business administration, or political science Dr. sc. soc.: Doctor scientiae socialis, Doctor of Social Sciences All of these doctoral degrees are equivalent to the PhD or ScD of the American system. Until German Reunification, universities in East Germany also awarded the Dr Sc. However, the East German Dr Sc was not equivalent to the PhD since it was adopted to replace the German Habilitation and therefore was equivalent to this higher-level qualification. After reunification the Habilitation was reintroduced at universities in Eastern Germany. The procedure of habilitation is normally required to receive officially the "venia docendi", which entitles the candidate to lecture at universities (Privatdozent, for men, or Privatdozentin, for women). The academic degree after the successful habilitation is e.g. Dr. rer. nat. habil., by adding the suffix "habil." to the earlier received Doctors degree. In Switzerland, the Dr sc. is a doctoral degree awarded only by the two Swiss Federal Institutes of Technology (EPFL and ETHZ), the University of Fribourg and the Department of Informatics of the University of Zurich. The Swiss Dr sc., like the DSc in the US, is equivalent to the PhD. It is earned with the approval of a committee on the basis of original research, publications, and extensive applied professional contributions and is awarded in doctoral level science and technology programs. Since 2004 the Dr sc. is the only doctoral degree awarded by the ETH Zurich. The École polytechnique fédérale de Lausanne awards the degree Docteur ès sciences, abbreviated Dr ès sc.and translated into English as PhD. === Poland === In Poland higher doctorate is Habilitation (habilitated doctor, doctor with habilitation) (doktor habilitowany or dr hab. in Polish) is the degree higher than PhD and it is awarded for substantial accomplishments in academic teaching, research and service after getting the PhD degree (usually up to 8 years of original research and multiple publications in peer reviewed scientific journals and monograph, habilitation dissertation after PhD). It is similar to habilitation degree in Germany and Austria. It is also similar (in terms of requirements) to associate professor with tenure. After achieving high degrees and rich research or artistic achievements, including as an academic teacher, lecturer, one can apply to become a professor. The President of Poland awards a scientist also in engineering (engineer) or artist the scientific title of professor (tytuł naukowy profesora) and the title of professor of art (tytuł profesora sztuki), respectively, in recognition of their scientific achievements and contributions to science, technology, and respectively their achievements in art and contributions to art. These titles are not academic/scientific or art degrees. However, possession of high degrees is required to receive the title. Habilitation has been a mandatory requirement for many years to apply for professorship in Poland. === United Kingdom, Ireland, India, Pakistan and the Commonwealth === In Ireland, the United Kingdom and the countries of the Commonwealth, such as Australia and India (in the Indian Institute of Technology, Bombay), the degree of Doctor of Science (DSc or ScD) is one of the Higher Doctorates. In some older universities it typically has precedence after Divinity, Laws or Civil Law, Medicine, and Letters, and above Music. The degree is conferred on a member of the university who has a proven record of internationally recognised scholarship. A candidate for the degree will usually be required to submit a selection of their publications that follow a consistent theme to the board of the appropriate faculty, which will decide if the candidate merits this accolade. Quite often they will need to be a doctoral graduate of at least ten years' standing and have a substantial research association with the awarding university. The first University to admit an individual to this degree was the University of London in 1860. In 1893 Maria Gordon (née Ogilvie) was the first woman to receive this degree. In former times the doctorate in science was regarded as a greater distinction than a professorial chair and hence a professor who was also a DSc would be known as Doctor. The Doctor of Science may also be awarded as an honorary degree, that is, given to individuals who have made extensive contributions to a particular field and not for specific academic accomplishments. It is usual to signify this by adding DSc h.c. (for honoris causa). === Other European Union countries === In the Czech Republic and Slovakia "Doctor of Sciences" (DrSc behind the name), established in 1953, is equivalent to the degree of Doctor of Science in the sense in which the DSc is used in the Commonwealth. It is the highest academic qualification, different from both PhD and PhDr. titles. In the Czech Republic, DrSc has not been awarded since 2001; instead, since 2006, a "Doctor of Sciences" degree (DSc behind the name) has been awarded, not by universities but by the Czech Academy of Sciences mostly for research in the field of natural or formal science. In Slovakia, "Doctor of Sciences" (DrSc) is awarded by the Slovak Academy of Sciences. In Hungary, "Doctor of Sciences" (DSc) is a higher doctorate degree and it is awarded by the Hungarian Academy of Sciences. In Finland, most doctoral degrees awarded in the fields of natural sciences, technology and economics are termed DSc degrees in English, with a suffix indicating the field of study. However, there is no translation of the term Doctor of Science to Finnish. For example, the proper translation for the doctorate in technology (tekniikan tohtori) would be DSc (Tech), whereas a doctorate in economics and business administration (kauppatieteiden tohtori) would be translated as DSc (Econ). When conversing or writing in English, the prefix Dr may be used to address a holder of a doctoral degree awarded in Finland. The degrees are equivalent to filosofian tohtori (FT, English: PhD), but FT is usually awarded only in general sciences, not in specializations like engineering, economics or medicine. In France, the Doctor of Sciences degree (doctorat en sciences also called doctorat d'État) was a higher doctorate in the fields of experimental and natural sciences, superseded in 1984 by the habilitation. In Denmark, Dr Scient. is a higher doctorate. In Bulgaria, "Doctor" (PhD) is the highest education level and first science degree. Doctor of Sciences (DrSc) is the second and the highest science degree. === Russia and other post-communist states === In Russia, the status of Russian Doktor Nauk (literally 'Doctor of Sciences') is considered a higher scientific degree. The equivalent to PhD is "Candidat Nauk" === Other European countries === In the former Yugoslavia, (Croatia, Serbia, Bosnia and Herzegovina, Montenegro, Slovenia, North Macedonia), title doktor nauka or doktor znanosti (literally "doctor of science") is used in a much broader sense than DSc, simply referring to a field of academic study – from art history (doktor znanosti/nauka povijesti umjetnosti), philosophy (doktor znanosti/nauka filozofije), and literary studies (doktor znanosti/nauka književnosti) to hard sciences such as molecular biology (doktor znanosti/nauka molekularne biologije). It is therefore formally recognized as a PhD degree. Starting in 2016, in Ukraine Doctor of Philosophy (PhD, Ukrainian: Доктор філософії) is the highest education level and first science degree. "Doctor of Sciences" (DSc Ukrainian: Доктор наук) is the second and the highest science degree, awarded in recognition of a substantial contribution to scientific knowledge, origination of new directions and visions in science. Since 2016, a PhD degree is one of the prerequisites for heading a university department in Ukraine. In Belarus "Doctor of Sciences" (DSc, Belarusian: Доктар навук) is the highest level of education that follows a PhD. Is awarded by The Higher Attestation Commission under the aegis of the President of the Republic of Belarus. == North America == === United States === In the United States, the formally recognized traditional Doctor of Science is an academic research doctoral degree awarded by research universities. The academic research ScD (or DSc) is not higher than a PhD as is the case in some European countries. The first North American ScD was inaugurated by Harvard University in 1872, when graduate studies first began at Harvard, and where the PhD and ScD degrees were introduced in the same year. The Doctor of Science research degree is earned with the formal dissertation defense and approval of a committee on the basis of original research and publications, and it is awarded predominantly in doctoral-level science programs, such as engineering, medical and health sciences, and health economics. Although rarer than the Doctor of Philosophy, the Doctor of Science is awarded by institutions including: Harvard University Columbia University Chapman University Middle Georgia State University Johns Hopkins University Massachusetts Institute of Technology, Capitol Technology University Bowie State University Towson University Tulane University University of Baltimore Marymount University Rocky Mountain University of Health Professions Aspen University in Computer Science University of Massachusetts Lowell in public health (epidemiology) Jacksonville State University in emergency management Spertus Institute for Jewish Learning and Leadership in Jewish studies. The George Washington University (although as of 2011 the university decided to offer only the more widely recognized PhD degree) A few university doctoral research programs offer both the Doctor of Science and Doctor of Philosophy degrees in the same academic field, such as Johns Hopkins University and Massachusetts Institute of Technology, with identical requirements for obtaining either. Research programs that offer the formal research ScD but not the PhD degree for a given field include several doctoral programs at Harvard University, Boston University, Capitol Technology University, and Texas Tech University Health Sciences Center. The University of Baltimore, School of Information Arts and Technologies offers a DSc degree in Information and Interaction Design, a program focused on usable design/user experience (UX) and Human Computer Interaction (HCI). There are programs where the Doctor of Science and Doctor of Philosophy have different degree requirements, though the two degrees are officially considered equivalent. The Engineering school at Washington University in St. Louis, for example, requires four more graduate courses in the DSc program, which can be completed in one year in conjunction with research duties, while the PhD requires teaching assistance services. The Johns Hopkins University also offers both PhD and ScD in certain programs, with only minor differences in university administration of the degrees. In some institutions, the ScD has been converted to the PhD. For instance, the doctoral degree in biostatistics at Harvard recently converted from ScD to PhD, even though the doctoral degree structure and requirements have remained identical. === Mexico === In Mexico the PhD level is considered a doctoral degree (level 8) similar to the doctorate degrees in Canada and the United States. The Doctor of Sciences degree is instead recognized as a Higher Degree (Grado Propio). === Costa Rica === In Costa Rica, doctorates are the highest academic degrees awarded by a university. They are focused on research and accessible only after the study of an academic Master's degree (as opposed to a professional Master's degree, intended for practical subjects). The University of Costa Rica, for example, offers a general Doctor of Sciences degree for students of all natural and exact sciences, a Doctor of Engineering degree for students of Engineering (in cooperation with the Costa Rica Institute of Technology), and a few other doctorate programs on applied sciences (for example, in Agricultural Sciences or Informatics). == South America == === Argentina === In Argentina the formal title Doctor of Science would be attributed to different fields of the hard or soft sciences. To get into an Argentine PhD program the applicant must have experience in research and at least an Engineering, Licentiate or master's degree: ==== Applied sciences ==== Doctorate of Agronomic Sciences (University of Buenos Aires, NU of LP, NU of C, NU of R, NU of MP, NU of the S) Doctorate of Sciences in Lacteal Technology (NU of the L) Doctorate of Sciences in Material Technology (NU of the S, NU of MP) Doctorate of Computer Sciences (University of Buenos Aires, NU of C, NU of SL, NU of the S) Doctorate of Engineering Sciences (NU of C, NU of Cu, NU of RC, NU of the S, ITBA) Doctorate of Geological Sciences (NU of C, NU of Cu, NU of SJ, NU of SL, NU of the S) Doctorate of Informatics Sciences (NU of LP) Doctorate of Basic Sciences Applied (NU of Q) Doctorate of Science and Technology (NU of GS) Doctorate of Geological Sciences (University of Buenos Aires) Doctorate of Molecular Biology and Biotechnology (NU of SAM) Doctorate of Systems Control (NU of the S) Doctorate of Economics Sciences (NU of LM) Doctorate of Economy (NU of LP, NU of the S) Doctorate of Geography (NU of the S) Doctorate of History (NU of the S) Doctorate of Chemical Engineering (NU of the S) ==== Basic sciences ==== Doctorate of Biological Sciences (U of BA, NU of LP, NU of C, NU of R, NU of the L, NU of Cu, NU of RC, NU of MP, NU of the S) Doctorate of Biological Chemistry Sciences (U of BA, NU of the S) Doctorate of Molecular Biology Sciences (U of BA) Doctorate of Mathematics Sciences (U of BA, NU of LP, NU of SL, NU of the S) Doctorate of Chemistry Sciences (NU of LP, NU of R, NU of C, NU of RC, NU of MP, NU of the S) Doctorate of Physics Sciences (U of BA, NU of LP, NU of MP, NU of SAM, NU of the S) Doctorate of Natural Sciences (U of BA, NU of LP) Doctorate of Philosophy (NU of the S) === Brazil === In Brazil only the Doctor in Sciences (DSc) category is recognized as a higher doctorate, generally followed by the concentration area (program field). This kind of doctorate is obtained in Graduate School after satisfactory evaluation of knowledge, research accomplishment, and thesis defense. This doctorate is comparable to a PhD program found in other countries. In the state of São Paulo, the doctorate title is the second highest academic title given by the state's universities (University of São Paulo (USP), State University of Campinas (UNICAMP) and São Paulo State University (UNESP)) and most Federal Universities, such as the Federal University of São Paulo (UNIFESP). The highest academic title is the Portuguese: Livre-Docência, which is not equivalent to the German Habilitation, since Portuguese: Livre-Docência is not a requisite to be a professor in Brazilian universities, and German Habilitation is a requisite to be a professor in German universities. However, Portuguese: Livre-Docência is a requisite to be promoted to Associate Professor / "full" Professor (Portuguese: Professor Titular) at several of those public research Universities. == References ==
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https://en.wikipedia.org/wiki/Doctor_of_Science
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Relationship science is an interdisciplinary field dedicated to the scientific study of interpersonal relationship processes. Due to its interdisciplinary nature, relationship science is made up of researchers of various professional backgrounds within psychology (e.g., clinical, social, and developmental psychologists) and outside of psychology (e.g., anthropologists, sociologists, economists, and biologists), but most researchers who identify with the field are psychologists by training. Additionally, the field's emphasis has historically been close and intimate relationships, which includes predominantly dating and married couples, parent-child relationships, and friendships and social networks, but some also study less salient social relationships such as colleagues and acquaintances. == History == === Early 20th century === Empirically studying interpersonal relationships and social connection traces back to the early 20th century when some of the earliest focuses were on family relationships from a sociological perspective—specifically, marriage and parenting. In 1938 the National Council on Family Relations (NCFR) was formed and, in 1939, what is now the Journal of Marriage and Family (JMF) was established to publish peer-reviewed research with this emphasis. In the 1930s, 1940s, and 1950s, researchers such as John Bowlby, Harry Harlow, Robert Hinde, and Mary Ainsworth began pursuing the study of mother–infant attachment. In 1949, Reuben Hill developed the ABC-X model, which is a theoretical framework used to examine how families manage and adapt to crises given the resources they have. Then, in the late 1950s and early 1960s, the purview of relationship research began to expand more, beyond the idea of just family research. In 1959, Stanley Schachter published the book The Psychology of Affiliation: Experimental Studies of the Sources of Gregariousness, where he discussed humans' general affiliative needs and how they are intensified by biological responses (e.g., anxiety and hunger). That same year, Harold (Hal) Kelley and John Thibaut published a book, The Social Psychology of Groups, that outlined interdependence theory—an interdisciplinary theory that would become an essential framework for understanding close relationships from a cost-benefit perspective in the years to come. However, this prior interest in relationships was infrequent, and it was not until the late 1960s and early 1970s that the study of relationships truly began to blossom and gain popularity, which was in large part due to the influence of Ellen Berscheid and Elaine Hatfield. === 1960s to 2000s === Roughly two decades after the aforementioned work of Hill and a decade after the works of Schachter, Kelley, and Thibaut, Ellen Berscheid and Elaine Hatfield (professors at the Universities of Minnesota and Wisconsin, respectively) began studying how two individuals become attracted to one another. Yet, their work went beyond just attraction and began to explore other domains such as the processes of choosing a romantic partner and falling in love, and the centrality of relationships in human health and well-being. However, being a female professor and researcher during the era (when academia was overwhelmingly dominated by white males) was incredibly difficult, and was only made more difficult by the public reception to their phenomena of interest. In 1974, their work came under fire after the senator of Wisconsin at the time alleged their research was a waste of taxpayer dollars, in light of Berscheid receiving $84,000 from the National Science Foundation to study love. Despite this immense scrutiny, they nevertheless persisted in pioneering the nascent field of relationship science through the 1970s and into the 1980s through seminal developments such as the distinction between passionate and companionate love and a scale to measure the former. Meanwhile, researchers from across different disciplines had begun to dedicate themselves to the study of relationships. Along with the fast growing interest came high-impact works. Urie Bronfenbrenner's late 1970s and mid-1980s social–ecological model established key principles that researchers would eventually use ubiquitously to study the impact of socio-contextual factors on relationships. Graham Spanier published the Dyadic Adjustment Scale (DAS) in JMF, which is currently the most widely cited scale of intimate relationship quality. John Bowlby's attachment theory, formalized in the late 1960s and early 1970s, laid the groundwork for the study of parent–child relationships and also helped shape the study of adult relationships in the field. Notably, in 1983, Harold Kelley, Ellen Berscheid, Andrew Christensen, Anne Peplau and their colleagues wrote the book Close Relationships, which provided a comprehensive overview of the field of relationship science in its early stages, and identified the typologies of relationships studied. Also in the 1980s and into the 1990s, Toni Antonucci began exploring friendships and social support among adults, while Arthur Aron was examining the role of relationships with romantic partners, siblings, friends, and parents in individual self-expansion. Additionally, Thomas Malloy and David Kenny developed the social relations model (an early analytic approach to understanding the roles of a person and their partner in their interactions) and Kenny later published his work on Models of Non-independence in Dyadic Research in 1996. With a growing interest in marriage and family therapy in relationship science, in the late 1980s and 1990s, researchers such as Howard Markman, Frank Floyd, and Scott Stanley began developing romantic relationship (with a primary focus on marriages) interventions; specifically, in 1995, Floyd and colleagues published the program they developed, called Prevention Intervention and Relationship Enhancement (PREP). Interest in and development of relationship education programming increased in the 2000s due to state and federal Healthy Marriage Initiatives, which allocated grant funding to support programming that would impact disadvantaged communities. Although there were many theoretical and empirical contributions of the 1970s and 80s, the professional evolution of relationship science was simultaneously taking place. The first international conference specifically dedicated to relationship processes took place in 1977 in Swansea, Wales, hosted by Mark Cook (a social psychologist) and Glen Wilson (a psychotherapist). In 1982, the first of the eventually bi-annual International Conference of Personal Relationships (ICPR) took place in Madison, Wisconsin, under the direction of Robin Gilmour and Steve Duck, with about 100 attendees. Two years later, in 1984, the International Society for the Study of Personal Relationships (ISSPR) was borne out of the ICPR and the Journal of Social and Personal Relationships, the first peer-reviewed journal unique to the field of relationship science, was established. Then in 1987, the Iowa Network of Personal Relationships (which would later be known as the International Network of Personal Relationships; INPR) was formed and Hal Kelley was elected president of ISSPR that same year. A few years later in 1991, Ellen Berscheid (the then-president of ISSPR) announced a merger of ISSPR and INPR, which ultimately fell through until the idea was reignited over a decade later. In 1994, the journal Personal Relationships was formally established by ISSPR and began publishing work in relationship science with Pat Noller as the editor; Anne Peplau became president of ISSPR. The changing of roles only persisted when Dan Perlman became president of ISSPR in 1996 and began discussing with the president of INPR (at the time, Barbara Sarason) how they might work to better integrate the efforts and goals of the two organizations; in 1998, Jeffry Simpson took over as editor of Personal Relationships. The decades-long, interdisciplinary study of relationships culminated in Ellen Berscheid's 1999 article "The Greening of Relationship Science". Here, Berscheid took the opportunity to close out the 20th-century with an overview of the field's past, present, and future. She described the uniqueness and benefits of a well-integrated interdisciplinary field and the advancements that have cemented the field as an "essential science".: 262 However, she also discussed the shortcomings that were stifling the progress of the field, and provided specific advice for overcoming such limitations in the upcoming century. Some of this advice included leaving behind traditional analytic approaches that fail to consider non-independence of individuals in relationships, and prioritizing the implementation of existing methods that consider interdependent and dyadic data as well as "creatively constructing new ones".: 261 Additionally, she stressed the dire need of the field to inform public opinion and policy related specifically to intimate relationship stability (e.g., quality, dissolution/divorce)—at the time, a hotly debated topic informed by partisan politics rather than empirical evidence, and for scientists to place greater emphasis on the environments in which relationships operate. Her article foreshadowed and influenced the evolution of the field in the 21st century, and its structure has since been adapted by other relationship researchers to reflect on how far the field has come and where it is going. === 2000s === The year 2000 included new developments in the field such as Nancy Collins and Brooke Feeney's work on partner support-seeking and caregiving in romantic relationships from an attachment theory perspective, and Reis, Sheldon, Gable, and colleagues' article "Daily Well-being: The Role of Autonomy, Competence, & Relatedness". A couple of years later, Rena Repetti, Shelley Taylor, and Teresa Seaman published work that addressed some of Berscheid's 1999 article concerns as well as used health psychology perspectives to inform relationship science. They empirically demonstrated the negative effects of family home environments with significant conflict and aggression on the mental and physical health of individuals in both childhood and adulthood. Simultaneously, the early 21st century was a time for major changes in the professional development of the field. In 2004, after previously unsuccessful attempts, ISSPR and INPR merged to form the International Association for Relationship Research (IARR). In 2007, Harry Reis published "Steps Toward the Ripening of Relationship Science", an article inspired by Ellen Berscheid's 1999 article, that recapped and made suggestions for furthering the field. He discussed important works that could be used as framework for guiding the field, including Thomas Bradbury's 2002 article, "Research on Relationships as a Prelude to Action"—an article focussed on the mechanisms for improvement of relationship research including better integration of research findings, more ethnically and culturally diverse sampling, and interdisciplinary, problem-centered approaches to research. Reis argued the need for integrating and organizing theories, for paying more attention to non-romantic relationships (the primary focus of the area) in research and intervention development, and the use of his theory of perceived partner responsiveness to enable this progress. Fast-forwarding to 2012, relationship researchers again heeded Berscheid's advice of using relationships science to inform real-world issues. Eli Finkel, Paul Eastwick, Benjamin Karney, Harry Reis, and Susan Sprecher wrote an article discussing the impact of online dating on relationship formation and both its positive and negative implications for relationship outcomes compared to traditional offline dating. Additionally, in 2018, Emily Impett and Amy Muise published their follow-up to Berscheid's article, "The Sexing of Relationship Science: Impetus for the Special Issue on Sex and Relationships". Here, they called on the field to draw more attention to and place greater weight on the role of sexual satisfaction; they identified this area of research as nascent but fertile territory to explore sexuality in relationships and establish it as an integral part of relationship science. == Types of relationships studied == The field recognizes that, for two individuals to be in the most basic form of a social relationship, they must be interdependent—that is, have interconnected behaviors and mutual influence on one another. === Personal relationships === A relationship is said to be personal when there is not only interdependence (the defining feature of all relationships), but when two people recognize each other as unique and unable to be replaced. Personal relationships can include colleagues, acquaintances, family members, and others, so long as the criteria for the relationship are met. === Close relationships === The definition of close relationships that is frequently referred back to is one from Harold Kelley and colleague's 1983 book, Close Relationships. This asserts that a close relationship is "one of strong, frequent, and diverse interdependence that lasts over a considerable period of time".: 38 This definition indicates that not even all personal relationships may be considered close relationships. Close relationships can include family relationships (e.g., parent–child, siblings, grandparent–grandchild, in-laws, etc.) and friendships. === Intimate relationships === What defines a relationship as intimate are the same features that comprise a close relationship (i.e., must be personal, must have bidirectional interdependence, and must be close), but there must also be a shared sexual passion or the potential to be sexually intimate. Intimate relationships can include married couples, dating partners, and other relationships that satisfy the aforementioned criteria. == Theories == === Social exchange theory === Social exchange theory was developed in the late 1950s and early 1960s as an economic approach to describing social experiences. It addresses the transactional nature of relationships whereby people determine how to proceed in a relationship after assessing the costs versus the benefits. A prominent subset that secured the place of social exchange theory in relationship science is interdependence theory, which was articulated in 1959 by Harold Kelley and John Thibaut in The Social Psychology of Groups. Even though Kelley and Thibaut's intent was to discuss the theory as it applied to groups, they began by exploring the effects of mutual influence as it pertains to two people together (i.e., a dyad). They expanded upon this process at the dyadic level in later years, further developing the idea that people in relationships 1) compare the overall positive to overall negative outcomes of their relationship (i.e., outcome = rewards - costs), which they then 2) compare to what they expect to get or think they should be getting out of the relationship (i.e., comparison level or "CL") to determine how satisfied they are (i.e., satisfaction = outcome - CL), and finally 3) compare the outcome of their relationship to the possible options of being either in another relationship or not in any relationship at all (i.e., comparison level for alternatives or "CLalt") to determine how dependent they are on the relationship/their partner (i.e., dependence = outcome - CLalt). They described this as having practical and important implications for commitment in a relationship such that those less satisfied by and less dependent on their partner may be more inclined to end the relationship (e.g., divorce, in the context of a marriage). Interdependence theory has also been the basis of other influential works, such as Caryl Rusbult's investment model theory. The investment model (later known as the 'investment model of commitment processes') directly adopts the principles of interdependence theory and extends it by asserting that the magnitude of an individual's investment of resources in the relationship increases the costs of leaving the relationship, which decreases the value of alternatives, and therefore increases commitment to the relationship. === Social learning theory === Social learning theory can be traced back to the 1940s and originated from the ideas of behaviorists like Clark L. Hull and B. F. Skinner. However, it was notably articulated by Albert Bandura in his 1971 book, Social Learning Theory. It is closely related to social exchange theory (and the subsequently developed interdependence theory), but focuses more on drawbacks and rewards found directly in behavior and interactions (e.g., distant vs. displays affection) opposed to broad costs and benefits. In the context of close and intimate relationships, it emphasizes that partners' behaviors (e.g., displays of empathy during a conversation) are central in that they not only invoke an immediate response, but teach one another what to believe and how to feel about their relationship (e.g., feeling secure and trusting), which affects how satisfied one is—a process that is described as cyclical. Social learning theory as it applies to relationship science led to the development of other prominent theories such as Gerald Patterson's coercion theory, outlined in his book, Coercive Family Process. Coercion theory focuses on why people end up in and stay in unhealthy relationships by explaining that individuals unintentionally reinforce each other's bad behaviors. This pattern is also described as cyclical where partners will continue to behave in a certain, negative way (e.g., nagging) when their partner reinforces said behavior (e.g., does what partner is requesting through nagging), which tells them that their negative behavior is effective at getting the outcome they desired. === Attachment theory === Attachment theory was formalized in a trilogy of books, Attachment and Loss, published in 1969, 1973, and 1980 by John Bowlby. The theory was originally developed to pertain to parent–child relationships, and more specifically during infancy. This idea that children rely on a primary caregiver—an attachment figure—to feel safe and confident to explore the world (a secure base) and come back to being loved, accepted, and supported (a safe haven) has been applied extensively to adult relationships. This was first applied by Cindy Hazan and Phillip Shaver in 1987, specifically in the context of romantic relationships. Their research found that not only were attachment styles (i.e., secure, avoidant, anxious/ambivalent) relatively stable from infancy and into adulthood, but that these three major styles predicted the ways in which adults experienced romantic relationships. This spawned nearly three-and-a-half decades of research exploring the importance of attachment processes in childhood (i.e., parent-child relationships) and their predictive value in adult relationship formation and maintenance (i.e., romantic partnerships, friendships). Influential people who have studied close and intimate relationships from an attachment perspective include Nancy Collins, Jeffry Simpson, and Chris Fraley. Nancy Collins and Stephen Read (1990) developed one of the most widely cited and used scales assessing adult attachment styles and, additionally, their dimensions. Their work found three dimensions and investigated the extent to which they applied to individual self-esteem, trust, etc. as well as gender differences in their relevance to relationship quality in dating couples. Jeffry Simpson has conducted extensive research on the influence of attachment styles on relationships, including documenting more negative and less positive emotions expressed in a relationship by individuals who were either anxious or avoidant. Chris Fraley's work on attachment includes a prominent study that used item response theory (IRT) to explore the psychometric properties of self-report adult attachment scales. His findings indicated very low levels of desirable psychometric properties in three out of four of the most commonly used adult attachment scales. Among improvements to existing scales, he made suggestions for the future development of adult attachment scales, including more discriminating items in the secure region and additional items to tap into the low ends of anxiety and avoidance dimensions. === Evolutionary theories === Evolutionary psychology as it pertains to relationship science is a collection of theories that aim to understand mating behaviors as a product of our ancestral past and adaptation. This set of perspectives has a common thread that links the modern-day study of relationship processes and behaviors to adaptive responses and features that were developed to maximize reproductive fitness. Sexual selection says that success in competition for mates happens for those who possess traits that are more attractive to potential mating partners. Researchers have also considered the theory of parental investment, where females (compared to males) have more to lose and ancestrally were therefore more selective in mate selection; this is one facet of many observed sex differences in mate selection where male and females seek and prefer certain traits. These theoretical perspectives have been implemented widely in the study of relationships both on their own and in an integrated approach (e.g., considering cultural context). Prominent works that have taken the evolutionary approach to studying relationship formation and processes include a review of existing research by Steven Gangstead and Martie Haselton (2015) that revealed differences in both women's sexual desires and men's reactions to women across the ovulation cycle. David Buss has extensively studied sex differences in cross-cultural mate selection, jealousy, and other relationship processes through research that integrates evolutionary perspectives with socio-cultural contexts (e.g., "Sex differences in human mate preferences: Evolutionary hypotheses tested in 37 cultures"; "Sex differences in jealousy: Evolution, physiology, and psychology", etc.). Additionally, Jeffry Simpson and Steven Gangstead have published widely cited work on relationship processes from an evolutionary lens, including research on human mating that discusses trade-offs (faced by females selecting a mate) between a potential mate's genetic fitness for having children and their willingness to help in child-rearing. === Social ecological theories === Social ecology—derived from sociology and anthropology—approaches the study of people in a way that considers the environment or context in which people live. Social ecological models, as they pertain to relationships, explain relationship processes from a lens that consider external forces acting upon people in a relationship, whether they be family members, romantic partners, or friends. Reuben Hill articulated one of the earliest documented social ecological models pertaining to relationship science—specifically families—in 1949. This is known as the ABC-X model or crisis theory. The 'A' in the model indicates a stressor; the 'B' indicates resources available to handle the stressor (both tangible and emotional); the 'C' indicates the interpretation of the stressor (whether it is perceived as a threat or manageable obstacle); finally, the 'X' indicates the crisis (the overall experience and response to the stressor that either strengthens or weakens families/couples). See Figure 1. In 1977, 1979, and 1986, Urie Bronfenbrenner published a model that integrated the multiple different levels or domains of an individual's environment. It was first developed to apply to child development, but has been widely applied in relationship science. The first level is the microsystem, which contains the single, immediate context people or dyads (e.g., couple, parent-child, friends) directly find themselves in—such as a home, school, or work. The second level is the mesosystem, which considers the combined effects of two or more contexts/settings. The third level is the exosystem, which also considers the effects of two or more contexts, but specifically contains at least one context that the individual or dyad is not directly in (e.g., government, social services) but affects an environment they are directly in (e.g., home, work). The fourth level is the macrosystem, which is the broader cultural and social attitudes that affect an individual. Finally, the chronosystem is the broadest level that is specifically the dimension of time as it relates to an individual's context changes and life events. See Figure 2. Researchers in relationship science have used social ecological models to study changes and stressors in relationships over time, and how couples, families, or even friends manage them given the contexts they evolve in. Application of social ecological models in relationship research have been seen in influential works such as Benjamin Karney and Thomas Bradbury's Vulnerability-Stress-Adaptation (VSA) model. The VSA model is a theoretical approach that enables researchers to study the impact of stressful events on relationship quality and stability over time (e.g., determine risk of divorce/relationship dissolution), given a couple's capacity to manage and adapt to such events. See Figure 3. ==== Relational mobility ==== In the early 2000s, a Japan-based research team defined relational mobility as a measure of how much choice individuals have in terms of whom to form relationships with, including friendships, romantic partnerships, and work relations. Relational mobility is low in cultures with a subsistence economy that requires tight cooperation and coordination, such as farming, while it is high in cultures based on nomadic herding and in urban industrial cultures. A cross-cultural study found that the relational mobility is lowest in East Asian countries where rice farming is common, and highest in South American countries. Differences in relational mobility can explain cultural differences in certain norms and behaviors, including conformity, shame, and business strategies, as well as differences in social cognition, including attribution and locus of control. == Methodologies == Relationship science has relied on a variety of methods for both data collection and analysis. This includes but is not limited to: cross-sectional data, longitudinal data, self-report study, observational study, experimental study, repeated measures design, and mixed-methods procedures. === Self-report data === Relationship science relies predominantly on individuals' self-reported evaluations and descriptions of their own relationship processes. This method of data collection often comes in the form of answering a questionnaire that requires either selection from a set of fixed responses or providing open-ended responses. It is often the simplest way to study relationships, but researchers have cautioned against solely relying on this form of measurement. Some issues that arise with the use of self-report data is the difficulty of accurately answering retrospective questions or questions that require introspection. Recently, particularly in light of the anti-false positive movement in psychology, relationship scientists are encouraging the use of multiple methods (e.g., self-report data, observational data) to study the same or similar constructs in different ways. However, an identified benefit of using specifically self-report questionnaires is that many of the measures used to study relationships are standardized and are therefore used in multiple different studies, where findings across studies can provide insight into replicability. === Experimental data === Some of the earliest studies conducted in relationship science were done using laboratory experiments. The field has since used experimental methods in order to infer causality about a relationship phenomenon of interest. This requires identification of a dependent variable that will be the measured effect (e.g., performance on a stressful task) and an independent variable that will be what is manipulated (e.g., social support vs. no social support). However, a common concern with experimental study of relationship phenomena is the potential lack of generalizability of laboratory setting findings to real-world contexts. === Observational data === Observational (or, behavioral) data in relationship science is a method of making inferences about relationship processes that relies on an observer's reports, rather than a participant's own reports of their relationship. This is often done through videotaping or audio recording participants' interactions with one another and having outside observers systematically identify (i.e., code) aspects of interest dependent upon the type of relationship being studied (e.g., patience exhibited during a parent-child activity; affection exhibited during a romantic couple's discussion). This method enables researchers to study aspects of a relationship that may be sub-conscious to participants or would otherwise not be detectable through self-report measures. However, a hurdle of observational research is establishing strong inter-rater reliability—that is, the level of agreement between observers who are coding the observations. Additionally, as participants often know they are being watched or recorded and such interactions often take place in laboratory settings, observational data collection presents the issue of reactivity—when individuals change their natural response or behavior because they are being watched. === Longitudinal data === A cornerstone of the research done in relationship science is the use of multi-wave assessments and subsequent repeated measures design, multi-level modeling (MLM), and structural equation modeling (SEM). As relationships themselves are longitudinal, this approach enables researchers to assess change across time within and/or between relationships. However, it must be noted that most of the longitudinal research in relationship science focuses on marriages and some on parent-child relationships, while relatively few longitudinal studies on friendships or other types of relationships exist. Within longitudinal research, there is additional variation in the length of time of the study; while some studies follow individuals, couples, parents and children, etc. over the course of a few years, some study change processes across the lifespan and in multiple different relationships (e.g., from infancy into adulthood). Additionally, the frequency of and intervals of time between multi-wave assessments has considerable variation in longitudinal research; one might employ intensive longitudinal methods that require daily assessments, methods that require monthly assessments, or methods that require annual or bi-annual assessments. === Interdependent and dyadic data === An important turning point in the analytic approach to studying relationships came at the advent of statistically modeling interdependence and dyadic processes—that is, studying two individuals (or even two groups of individuals) simultaneously to account for the overlap in or interdependence of relationship processes. In 2006, David Kenny, Deborah Kashy, and William Cook published the book Dyadic Data Analysis, which has been widely cited as a tool of understanding and measuring non-independence. This book includes information and instructions on using MLM, SEM, and other statistical methods to study both between and within dyad phenomena. Several models have been articulated for these purposes in both journal articles and the 2006 Kenny, Kashy, & Cook text, including 1) the common fate model, 2) the mutual influence (or dyadic feedback) model, 3) the dyadic score model, and the most commonly used 4) actor-partner interdependence model (APIM). ==== Common fate model ==== The common fate model is a method of estimating not how two people influence one another, but how two people are similarly influenced by an external force. Dyadic means are computed for both the independent and dependent variable to estimate the effects of the dyad as a single unit. The between-dyad correlations are adjusted by the within-dyad correlations in order to remove individual-level variation. The two partners' predictor and outcome variables are observed variables that are used to compute latent variables (i.e., the 'common fate variables'). See Figure 4. ==== Mutual influence (dyadic feedback) model ==== The mutual influence or dyadic feedback model is a method of considering reciprocal influence of partners' predictor(s) on one another's and partners' outcome on one another's. Compared to the APIM, this model assumes there are no partner effects and no other types of non-independence, as seen in the predictor-predictor and outcome-outcome paths. Additionally, it assumes equal effects of partner's influence on one another (i.e., 1 influences 2 equally as 2 influences 1). See Figure 5. ==== Dyadic score model ==== The dyadic score model uses two partners observed predictor and outcome variables to compute both dyadic 'level' and 'difference' latent variables. The level variables are similar to the common fate latent variables while the difference variables represent the within-dyad contrast. See Figure 6. ==== Actor-partner interdependence model (APIM) ==== The APIM is a method of accounting for dyadic interdependence via both actor and partner effects. Specifically, it considers the influence of one partner's predictor(s) on the other partner's predictor(s) and outcome. This is modeled using regression, MLM, or SEM procedures. See Figure 7. == See also == == References ==
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https://en.wikipedia.org/wiki/Relationship_science
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The history of science covers the development of science from ancient times to the present. It encompasses all three major branches of science: natural, social, and formal. Protoscience, early sciences, and natural philosophies such as alchemy and astrology that existed during the Bronze Age, Iron Age, classical antiquity and the Middle Ages, declined during the early modern period after the establishment of formal disciplines of science in the Age of Enlightenment. The earliest roots of scientific thinking and practice can be traced to Ancient Egypt and Mesopotamia during the 3rd and 2nd millennia BCE. These civilizations' contributions to mathematics, astronomy, and medicine influenced later Greek natural philosophy of classical antiquity, wherein formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Latin-speaking Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but continued to thrive in the Greek-speaking Byzantine Empire. Aided by translations of Greek texts, the Hellenistic worldview was preserved and absorbed into the Arabic-speaking Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived the learning of natural philosophy in the West. Traditions of early science were also developed in ancient India and separately in ancient China, the Chinese model having influenced Vietnam, Korea and Japan before Western exploration. Among the Pre-Columbian peoples of Mesoamerica, the Zapotec civilization established their first known traditions of astronomy and mathematics for producing calendars, followed by other civilizations such as the Maya. Natural philosophy was transformed by the Scientific Revolution that transpired during the 16th and 17th centuries in Europe, as new ideas and discoveries departed from previous Greek conceptions and traditions. The New Science that emerged was more mechanistic in its worldview, more integrated with mathematics, and more reliable and open as its knowledge was based on a newly defined scientific method. More "revolutions" in subsequent centuries soon followed. The chemical revolution of the 18th century, for instance, introduced new quantitative methods and measurements for chemistry. In the 19th century, new perspectives regarding the conservation of energy, age of Earth, and evolution came into focus. And in the 20th century, new discoveries in genetics and physics laid the foundations for new sub disciplines such as molecular biology and particle physics. Moreover, industrial and military concerns as well as the increasing complexity of new research endeavors ushered in the era of "big science," particularly after World War II. == Approaches to history of science == The nature of the history of science is a topic of debate (as is, by implication, the definition of science itself). The history of science is often seen as a linear story of progress, but historians have come to see the story as more complex. Alfred Edward Taylor has characterised lean periods in the advance of scientific discovery as "periodical bankruptcies of science". Science is a human activity, and scientific contributions have come from people from a wide range of different backgrounds and cultures. Historians of science increasingly see their field as part of a global history of exchange, conflict and collaboration. The relationship between science and religion has been variously characterized in terms of "conflict", "harmony", "complexity", and "mutual independence", among others. Events in Europe such as the Galileo affair of the early 17th century – associated with the scientific revolution and the Age of Enlightenment – led scholars such as John William Draper to postulate (c. 1874) a conflict thesis, suggesting that religion and science have been in conflict methodologically, factually and politically throughout history. The "conflict thesis" has since lost favor among the majority of contemporary scientists and historians of science. However, some contemporary philosophers and scientists, such as Richard Dawkins, still subscribe to this thesis. Historians have emphasized that trust is necessary for agreement on claims about nature. In this light, the 1660 establishment of the Royal Society and its code of experiment – trustworthy because witnessed by its members – has become an important chapter in the historiography of science. Many people in modern history (typically women and persons of color) were excluded from elite scientific communities and characterized by the science establishment as inferior. Historians in the 1980s and 1990s described the structural barriers to participation and began to recover the contributions of overlooked individuals. Historians have also investigated the mundane practices of science such as fieldwork and specimen collection, correspondence, drawing, record-keeping, and the use of laboratory and field equipment. == Prehistory == In prehistoric times, knowledge and technique were passed from generation to generation in an oral tradition. For instance, the domestication of maize for agriculture has been dated to about 9,000 years ago in southern Mexico, before the development of writing systems. Similarly, archaeological evidence indicates the development of astronomical knowledge in preliterate societies. The oral tradition of preliterate societies had several features, the first of which was its fluidity. New information was constantly absorbed and adjusted to new circumstances or community needs. There were no archives or reports. This fluidity was closely related to the practical need to explain and justify a present state of affairs. Another feature was the tendency to describe the universe as just sky and earth, with a potential underworld. They were also prone to identify causes with beginnings, thereby providing a historical origin with an explanation. There was also a reliance on a "medicine man" or "wise woman" for healing, knowledge of divine or demonic causes of diseases, and in more extreme cases, for rituals such as exorcism, divination, songs, and incantations. Finally, there was an inclination to unquestioningly accept explanations that might be deemed implausible in more modern times while at the same time not being aware that such credulous behaviors could have posed problems. The development of writing enabled humans to store and communicate knowledge across generations with much greater accuracy. Its invention was a prerequisite for the development of philosophy and later science in ancient times. Moreover, the extent to which philosophy and science would flourish in ancient times depended on the efficiency of a writing system (e.g., use of alphabets). == Ancient Near East == The earliest roots of science can be traced to the Ancient Near East c. 3000–1200 BCE – in particular to Ancient Egypt and Mesopotamia. === Ancient Egypt === ==== Number system and geometry ==== Starting c. 3000 BCE, the ancient Egyptians developed a numbering system that was decimal in character and had oriented their knowledge of geometry to solving practical problems such as those of surveyors and builders. Their development of geometry was itself a necessary development of surveying to preserve the layout and ownership of farmland, which was flooded annually by the Nile. The 3-4-5 right triangle and other rules of geometry were used to build rectilinear structures, and the post and lintel architecture of Egypt. ==== Disease and healing ==== Egypt was also a center of alchemy research for much of the Mediterranean. According to the medical papyri (written c. 2500–1200 BCE), the ancient Egyptians believed that disease was mainly caused by the invasion of bodies by evil forces or spirits. Thus, in addition to medicine, therapies included prayer, incantation, and ritual. The Ebers Papyrus, written c. 1600 BCE, contains medical recipes for treating diseases related to the eyes, mouth, skin, internal organs, and extremities, as well as abscesses, wounds, burns, ulcers, swollen glands, tumors, headaches, and bad breath. The Edwin Smith Papyrus, written at about the same time, contains a surgical manual for treating wounds, fractures, and dislocations. The Egyptians believed that the effectiveness of their medicines depended on the preparation and administration under appropriate rituals. Medical historians believe that ancient Egyptian pharmacology, for example, was largely ineffective. Both the Ebers and Edwin Smith papyri applied the following components to the treatment of disease: examination, diagnosis, treatment, and prognosis, which display strong parallels to the basic empirical method of science and, according to G. E. R. Lloyd, played a significant role in the development of this methodology. ==== Calendar ==== The ancient Egyptians even developed an official calendar that contained twelve months, thirty days each, and five days at the end of the year. Unlike the Babylonian calendar or the ones used in Greek city-states at the time, the official Egyptian calendar was much simpler as it was fixed and did not take lunar and solar cycles into consideration. === Mesopotamia === The ancient Mesopotamians had extensive knowledge about the chemical properties of clay, sand, metal ore, bitumen, stone, and other natural materials, and applied this knowledge to practical use in manufacturing pottery, faience, glass, soap, metals, lime plaster, and waterproofing. Metallurgy required knowledge about the properties of metals. Nonetheless, the Mesopotamians seem to have had little interest in gathering information about the natural world for the mere sake of gathering information and were far more interested in studying the manner in which the gods had ordered the universe. Biology of non-human organisms was generally only written about in the context of mainstream academic disciplines. Animal physiology was studied extensively for the purpose of divination; the anatomy of the liver, which was seen as an important organ in haruspicy, was studied in particularly intensive detail. Animal behavior was also studied for divinatory purposes. Most information about the training and domestication of animals was probably transmitted orally without being written down, but one text dealing with the training of horses has survived. ==== Mesopotamian medicine ==== The ancient Mesopotamians had no distinction between "rational science" and magic. When a person became ill, doctors prescribed magical formulas to be recited as well as medicinal treatments. The earliest medical prescriptions appear in Sumerian during the Third Dynasty of Ur (c. 2112 BCE – c. 2004 BCE). The most extensive Babylonian medical text, however, is the Diagnostic Handbook written by the ummânū, or chief scholar, Esagil-kin-apli of Borsippa, during the reign of the Babylonian king Adad-apla-iddina (1069–1046 BCE). In East Semitic cultures, the main medicinal authority was a kind of exorcist-healer known as an āšipu. The profession was generally passed down from father to son and was held in extremely high regard. Of less frequent recourse was another kind of healer known as an asu, who corresponds more closely to a modern physician and treated physical symptoms using primarily folk remedies composed of various herbs, animal products, and minerals, as well as potions, enemas, and ointments or poultices. These physicians, who could be either male or female, also dressed wounds, set limbs, and performed simple surgeries. The ancient Mesopotamians also practiced prophylaxis and took measures to prevent the spread of disease. ==== Astronomy and celestial divination ==== In Babylonian astronomy, records of the motions of the stars, planets, and the moon are left on thousands of clay tablets created by scribes. Even today, astronomical periods identified by Mesopotamian proto-scientists are still widely used in Western calendars such as the solar year and the lunar month. Using this data, they developed mathematical methods to compute the changing length of daylight in the course of the year, predict the appearances and disappearances of the Moon and planets, and eclipses of the Sun and Moon. Only a few astronomers' names are known, such as that of Kidinnu, a Chaldean astronomer and mathematician. Kiddinu's value for the solar year is in use for today's calendars. Babylonian astronomy was "the first and highly successful attempt at giving a refined mathematical description of astronomical phenomena." According to the historian A. Aaboe, "all subsequent varieties of scientific astronomy, in the Hellenistic world, in India, in Islam, and in the West—if not indeed all subsequent endeavour in the exact sciences—depend upon Babylonian astronomy in decisive and fundamental ways." To the Babylonians and other Near Eastern cultures, messages from the gods or omens were concealed in all natural phenomena that could be deciphered and interpreted by those who are adept. Hence, it was believed that the gods could speak through all terrestrial objects (e.g., animal entrails, dreams, malformed births, or even the color of a dog urinating on a person) and celestial phenomena. Moreover, Babylonian astrology was inseparable from Babylonian astronomy. ==== Mathematics ==== The Mesopotamian cuneiform tablet Plimpton 322, dating to the 18th century BCE, records a number of Pythagorean triplets (3, 4, 5) and (5, 12, 13) ..., hinting that the ancient Mesopotamians might have been aware of the Pythagorean theorem over a millennium before Pythagoras. == Ancient and medieval South Asia and East Asia == Mathematical achievements from Mesopotamia had some influence on the development of mathematics in India, and there were confirmed transmissions of mathematical ideas between India and China, which were bidirectional. Nevertheless, the mathematical and scientific achievements in India and particularly in China occurred largely independently from those of Europe and the confirmed early influences that these two civilizations had on the development of science in Europe in the pre-modern era were indirect, with Mesopotamia and later the Islamic World acting as intermediaries. The arrival of modern science, which grew out of the Scientific Revolution, in India and China and the greater Asian region in general can be traced to the scientific activities of Jesuit missionaries who were interested in studying the region's flora and fauna during the 16th to 17th century. === India === ==== Mathematics ==== The earliest traces of mathematical knowledge in the Indian subcontinent appear with the Indus Valley Civilisation (c. 3300 – c. 1300 BCE). The people of this civilization made bricks whose dimensions were in the proportion 4:2:1, which is favorable for the stability of a brick structure. They also tried to standardize measurement of length to a high degree of accuracy. They designed a ruler—the Mohenjo-daro ruler—whose length of approximately 1.32 in (34 mm) was divided into ten equal parts. Bricks manufactured in ancient Mohenjo-daro often had dimensions that were integral multiples of this unit of length. The Bakhshali manuscript contains problems involving arithmetic, algebra and geometry, including mensuration. The topics covered include fractions, square roots, arithmetic and geometric progressions, solutions of simple equations, simultaneous linear equations, quadratic equations and indeterminate equations of the second degree. In the 3rd century BCE, Pingala presents the Pingala-sutras, the earliest known treatise on Sanskrit prosody. He also presents a numerical system by adding one to the sum of place values. Pingala's work also includes material related to the Fibonacci numbers, called mātrāmeru. Indian astronomer and mathematician Aryabhata (476–550), in his Aryabhatiya (499) introduced the sine function in trigonometry and the number 0. In 628, Brahmagupta suggested that gravity was a force of attraction. He also lucidly explained the use of zero as both a placeholder and a decimal digit, along with the Hindu–Arabic numeral system now used universally throughout the world. Arabic translations of the two astronomers' texts were soon available in the Islamic world, introducing what would become Arabic numerals to the Islamic world by the 9th century. Narayana Pandita (1340–1400) was an Indian mathematician. Plofker writes that his texts were the most significant Sanskrit mathematics treatises after those of Bhaskara II, other than the Kerala school.: 52 He wrote the Ganita Kaumudi (lit. "Moonlight of mathematics") in 1356 about mathematical operations. The work anticipated many developments in combinatorics. Between the 14th and 16th centuries, the Kerala school of astronomy and mathematics made significant advances in astronomy and especially mathematics, including fields such as trigonometry and analysis. In particular, Madhava of Sangamagrama led advancement in analysis by providing the infinite and taylor series expansion of some trigonometric functions and pi approximation. Parameshvara (1380–1460), presents a case of the Mean Value theorem in his commentaries on Govindasvāmi and Bhāskara II. The Yuktibhāṣā was written by Jyeshtadeva in 1530. ==== Astronomy ==== The first textual mention of astronomical concepts comes from the Vedas, religious literature of India. According to Sarma (2008): "One finds in the Rigveda intelligent speculations about the genesis of the universe from nonexistence, the configuration of the universe, the spherical self-supporting earth, and the year of 360 days divided into 12 equal parts of 30 days each with a periodical intercalary month.". The first 12 chapters of the Siddhanta Shiromani, written by Bhāskara in the 12th century, cover topics such as: mean longitudes of the planets; true longitudes of the planets; the three problems of diurnal rotation; syzygies; lunar eclipses; solar eclipses; latitudes of the planets; risings and settings; the moon's crescent; conjunctions of the planets with each other; conjunctions of the planets with the fixed stars; and the patas of the sun and moon. The 13 chapters of the second part cover the nature of the sphere, as well as significant astronomical and trigonometric calculations based on it. In the Tantrasangraha treatise, Nilakantha Somayaji's updated the Aryabhatan model for the interior planets, Mercury, and Venus and the equation that he specified for the center of these planets was more accurate than the ones in European or Islamic astronomy until the time of Johannes Kepler in the 17th century. Jai Singh II of Jaipur constructed five observatories called Jantar Mantars in total, in New Delhi, Jaipur, Ujjain, Mathura and Varanasi; they were completed between 1724 and 1735. ==== Grammar ==== Some of the earliest linguistic activities can be found in Iron Age India (1st millennium BCE) with the analysis of Sanskrit for the purpose of the correct recitation and interpretation of Vedic texts. The most notable grammarian of Sanskrit was Pāṇini (c. 520–460 BCE), whose grammar formulates close to 4,000 rules for Sanskrit. Inherent in his analytic approach are the concepts of the phoneme, the morpheme and the root. The Tolkāppiyam text, composed in the early centuries of the common era, is a comprehensive text on Tamil grammar, which includes sutras on orthography, phonology, etymology, morphology, semantics, prosody, sentence structure and the significance of context in language. ==== Medicine ==== Findings from Neolithic graveyards in what is now Pakistan show evidence of proto-dentistry among an early farming culture. The ancient text Suśrutasamhitā of Suśruta describes procedures on various forms of surgery, including rhinoplasty, the repair of torn ear lobes, perineal lithotomy, cataract surgery, and several other excisions and other surgical procedures. The Charaka Samhita of Charaka describes ancient theories on human body, etiology, symptomology and therapeutics for a wide range of diseases. It also includes sections on the importance of diet, hygiene, prevention, medical education, and the teamwork of a physician, nurse and patient necessary for recovery to health. ==== Politics and state ==== An ancient Indian treatise on statecraft, economic policy and military strategy by Kautilya and Viṣhṇugupta, who are traditionally identified with Chāṇakya (c. 350–283 BCE). In this treatise, the behaviors and relationships of the people, the King, the State, the Government Superintendents, Courtiers, Enemies, Invaders, and Corporations are analyzed and documented. Roger Boesche describes the Arthaśāstra as "a book of political realism, a book analyzing how the political world does work and not very often stating how it ought to work, a book that frequently discloses to a king what calculating and sometimes brutal measures he must carry out to preserve the state and the common good." ==== Logic ==== The development of Indian logic dates back to the Chandahsutra of Pingala and anviksiki of Medhatithi Gautama (c. 6th century BCE); the Sanskrit grammar rules of Pāṇini (c. 5th century BCE); the Vaisheshika school's analysis of atomism (c. 6th century BCE to 2nd century BCE); the analysis of inference by Gotama (c. 6th century BCE to 2nd century CE), founder of the Nyaya school of Hindu philosophy; and the tetralemma of Nagarjuna (c. 2nd century CE). Indian logic stands as one of the three original traditions of logic, alongside the Greek and the Chinese logic. The Indian tradition continued to develop through early to modern times, in the form of the Navya-Nyāya school of logic. In the 2nd century, the Buddhist philosopher Nagarjuna refined the Catuskoti form of logic. The Catuskoti is also often glossed Tetralemma (Greek) which is the name for a largely comparable, but not equatable, 'four corner argument' within the tradition of Classical logic. Navya-Nyāya developed a sophisticated language and conceptual scheme that allowed it to raise, analyse, and solve problems in logic and epistemology. It systematised all the Nyāya concepts into four main categories: sense or perception (pratyakşa), inference (anumāna), comparison or similarity (upamāna), and testimony (sound or word; śabda). === China === ==== Chinese mathematics ==== From the earliest the Chinese used a positional decimal system on counting boards in order to calculate. To express 10, a single rod is placed in the second box from the right. The spoken language uses a similar system to English: e.g. four thousand two hundred and seven. No symbol was used for zero. By the 1st century BCE, negative numbers and decimal fractions were in use and The Nine Chapters on the Mathematical Art included methods for extracting higher order roots by Horner's method and solving linear equations and by Pythagoras' theorem. Cubic equations were solved in the Tang dynasty and solutions of equations of order higher than 3 appeared in print in 1245 CE by Ch'in Chiu-shao. Pascal's triangle for binomial coefficients was described around 1100 by Jia Xian. Although the first attempts at an axiomatization of geometry appear in the Mohist canon in 330 BCE, Liu Hui developed algebraic methods in geometry in the 3rd century CE and also calculated pi to 5 significant figures. In 480, Zu Chongzhi improved this by discovering the ratio 355 113 {\displaystyle {\tfrac {355}{113}}} which remained the most accurate value for 1200 years. ==== Astronomical observations ==== Astronomical observations from China constitute the longest continuous sequence from any civilization and include records of sunspots (112 records from 364 BCE), supernovas (1054), lunar and solar eclipses. By the 12th century, they could reasonably accurately make predictions of eclipses, but the knowledge of this was lost during the Ming dynasty, so that the Jesuit Matteo Ricci gained much favor in 1601 by his predictions. By 635 Chinese astronomers had observed that the tails of comets always point away from the sun. From antiquity, the Chinese used an equatorial system for describing the skies and a star map from 940 was drawn using a cylindrical (Mercator) projection. The use of an armillary sphere is recorded from the 4th century BCE and a sphere permanently mounted in equatorial axis from 52 BCE. In 125 CE Zhang Heng used water power to rotate the sphere in real time. This included rings for the meridian and ecliptic. By 1270 they had incorporated the principles of the Arab torquetum. In the Song Empire (960–1279) of Imperial China, Chinese scholar-officials unearthed, studied, and cataloged ancient artifacts. ==== Inventions ==== To better prepare for calamities, Zhang Heng invented a seismometer in 132 CE which provided instant alert to authorities in the capital Luoyang that an earthquake had occurred in a location indicated by a specific cardinal or ordinal direction. Although no tremors could be felt in the capital when Zhang told the court that an earthquake had just occurred in the northwest, a message came soon afterwards that an earthquake had indeed struck 400 to 500 km (250 to 310 mi) northwest of Luoyang (in what is now modern Gansu). Zhang called his device the 'instrument for measuring the seasonal winds and the movements of the Earth' (Houfeng didong yi 候风地动仪), so-named because he and others thought that earthquakes were most likely caused by the enormous compression of trapped air. There are many notable contributors to early Chinese disciplines, inventions, and practices throughout the ages. One of the best examples would be the medieval Song Chinese Shen Kuo (1031–1095), a polymath and statesman who was the first to describe the magnetic-needle compass used for navigation, discovered the concept of true north, improved the design of the astronomical gnomon, armillary sphere, sight tube, and clepsydra, and described the use of drydocks to repair boats. After observing the natural process of the inundation of silt and the find of marine fossils in the Taihang Mountains (hundreds of miles from the Pacific Ocean), Shen Kuo devised a theory of land formation, or geomorphology. He also adopted a theory of gradual climate change in regions over time, after observing petrified bamboo found underground at Yan'an, Shaanxi. If not for Shen Kuo's writing, the architectural works of Yu Hao would be little known, along with the inventor of movable type printing, Bi Sheng (990–1051). Shen's contemporary Su Song (1020–1101) was also a brilliant polymath, an astronomer who created a celestial atlas of star maps, wrote a treatise related to botany, zoology, mineralogy, and metallurgy, and had erected a large astronomical clocktower in Kaifeng city in 1088. To operate the crowning armillary sphere, his clocktower featured an escapement mechanism and the world's oldest known use of an endless power-transmitting chain drive. The Jesuit China missions of the 16th and 17th centuries "learned to appreciate the scientific achievements of this ancient culture and made them known in Europe. Through their correspondence European scientists first learned about the Chinese science and culture." Western academic thought on the history of Chinese technology and science was galvanized by the work of Joseph Needham and the Needham Research Institute. Among the technological accomplishments of China were, according to the British scholar Needham, the water-powered celestial globe (Zhang Heng), dry docks, sliding calipers, the double-action piston pump, the blast furnace, the multi-tube seed drill, the wheelbarrow, the suspension bridge, the winnowing machine, gunpowder, the raised-relief map, toilet paper, the efficient harness, along with contributions in logic, astronomy, medicine, and other fields. However, cultural factors prevented these Chinese achievements from developing into "modern science". According to Needham, it may have been the religious and philosophical framework of Chinese intellectuals which made them unable to accept the ideas of laws of nature: It was not that there was no order in nature for the Chinese, but rather that it was not an order ordained by a rational personal being, and hence there was no conviction that rational personal beings would be able to spell out in their lesser earthly languages the divine code of laws which he had decreed aforetime. The Taoists, indeed, would have scorned such an idea as being too naïve for the subtlety and complexity of the universe as they intuited it. == Pre-Columbian Mesoamerica == During the Middle Formative Period (c. 900 BCE – c. 300 BCE) of Pre-Columbian Mesoamerica, the Zapotec civilization, heavily influenced by the Olmec civilization, established the first known full writing system of the region (possibly predated by the Olmec Cascajal Block), as well as the first known astronomical calendar in Mesoamerica. Following a period of initial urban development in the Preclassical period, the Classic Maya civilization (c. 250 CE – c. 900 CE) built on the shared heritage of the Olmecs by developing the most sophisticated systems of writing, astronomy, calendrical science, and mathematics among Mesoamerican peoples. The Maya developed a positional numeral system with a base of 20 that included the use of zero for constructing their calendars. Maya writing, which was developed by 200 BCE, widespread by 100 BCE, and rooted in Olmec and Zapotec scripts, contains easily discernible calendar dates in the form of logographs representing numbers, coefficients, and calendar periods amounting to 20 days and even 20 years for tracking social, religious, political, and economic events in 360-day years. == Classical antiquity and Greco-Roman science == The contributions of the Ancient Egyptians and Mesopotamians in the areas of astronomy, mathematics, and medicine had entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. Inquiries were also aimed at such practical goals such as establishing a reliable calendar or determining how to cure a variety of illnesses. The ancient people who were considered the first scientists may have thought of themselves as natural philosophers, as practitioners of a skilled profession (for example, physicians), or as followers of a religious tradition (for example, temple healers). === Pre-socratics === The earliest Greek philosophers, known as the pre-Socratics, provided competing answers to the question found in the myths of their neighbors: "How did the ordered cosmos in which we live come to be?" The pre-Socratic philosopher Thales (640–546 BCE) of Miletus, identified by later authors such as Aristotle as the first of the Ionian philosophers, postulated non-supernatural explanations for natural phenomena. For example, that land floats on water and that earthquakes are caused by the agitation of the water upon which the land floats, rather than the god Poseidon. Thales' student Pythagoras of Samos founded the Pythagorean school, which investigated mathematics for its own sake, and was the first to postulate that the Earth is spherical in shape. Leucippus (5th century BCE) introduced atomism, the theory that all matter is made of indivisible, imperishable units called atoms. This was greatly expanded on by his pupil Democritus and later Epicurus. === Natural philosophy === Plato and Aristotle produced the first systematic discussions of natural philosophy, which did much to shape later investigations of nature. Their development of deductive reasoning was of particular importance and usefulness to later scientific inquiry. Plato founded the Platonic Academy in 387 BCE, whose motto was "Let none unversed in geometry enter here," and also turned out many notable philosophers. Plato's student Aristotle introduced empiricism and the notion that universal truths can be arrived at via observation and induction, thereby laying the foundations of the scientific method. Aristotle also produced many biological writings that were empirical in nature, focusing on biological causation and the diversity of life. He made countless observations of nature, especially the habits and attributes of plants and animals on Lesbos, classified more than 540 animal species, and dissected at least 50. Aristotle's writings profoundly influenced subsequent Islamic and European scholarship, though they were eventually superseded in the Scientific Revolution. Aristotle also contributed to theories of the elements and the cosmos. He believed that the celestial bodies (such as the planets and the Sun) had something called an unmoved mover that put the celestial bodies in motion. Aristotle tried to explain everything through mathematics and physics, but sometimes explained things such as the motion of celestial bodies through a higher power such as God. Aristotle did not have the technological advancements that would have explained the motion of celestial bodies. In addition, Aristotle had many views on the elements. He believed that everything was derived of the elements earth, water, air, fire, and lastly the Aether. The Aether was a celestial element, and therefore made up the matter of the celestial bodies. The elements of earth, water, air and fire were derived of a combination of two of the characteristics of hot, wet, cold, and dry, and all had their inevitable place and motion. The motion of these elements begins with earth being the closest to "the Earth," then water, air, fire, and finally Aether. In addition to the makeup of all things, Aristotle came up with theories as to why things did not return to their natural motion. He understood that water sits above earth, air above water, and fire above air in their natural state. He explained that although all elements must return to their natural state, the human body and other living things have a constraint on the elements – thus not allowing the elements making one who they are to return to their natural state. The important legacy of this period included substantial advances in factual knowledge, especially in anatomy, zoology, botany, mineralogy, geography, mathematics and astronomy; an awareness of the importance of certain scientific problems, especially those related to the problem of change and its causes; and a recognition of the methodological importance of applying mathematics to natural phenomena and of undertaking empirical research. In the Hellenistic age scholars frequently employed the principles developed in earlier Greek thought: the application of mathematics and deliberate empirical research, in their scientific investigations. Thus, clear unbroken lines of influence lead from ancient Greek and Hellenistic philosophers, to medieval Muslim philosophers and scientists, to the European Renaissance and Enlightenment, to the secular sciences of the modern day. Neither reason nor inquiry began with the Ancient Greeks, but the Socratic method did, along with the idea of Forms, give great advances in geometry, logic, and the natural sciences. According to Benjamin Farrington, former professor of Classics at Swansea University: "Men were weighing for thousands of years before Archimedes worked out the laws of equilibrium; they must have had practical and intuitional knowledge of the principals involved. What Archimedes did was to sort out the theoretical implications of this practical knowledge and present the resulting body of knowledge as a logically coherent system." and again: "With astonishment we find ourselves on the threshold of modern science. Nor should it be supposed that by some trick of translation the extracts have been given an air of modernity. Far from it. The vocabulary of these writings and their style are the source from which our own vocabulary and style have been derived." === Greek astronomy === The astronomer Aristarchus of Samos was the first known person to propose a heliocentric model of the Solar System, while the geographer Eratosthenes accurately calculated the circumference of the Earth. Hipparchus (c. 190 – c. 120 BCE) produced the first systematic star catalog. The level of achievement in Hellenistic astronomy and engineering is impressively shown by the Antikythera mechanism (150–100 BCE), an analog computer for calculating the position of planets. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe. === Hellenistic medicine === There was not a defined societal structure for healthcare during the age of Hippocrates. At that time, society was not organized and knowledgeable as people still relied on pure religious reasoning to explain illnesses. Hippocrates introduced the first healthcare system based on science and clinical protocols. Hippocrates' theories about physics and medicine helped pave the way in creating an organized medical structure for society. In medicine, Hippocrates (c. 460–370 BCE) and his followers were the first to describe many diseases and medical conditions and developed the Hippocratic Oath for physicians, still relevant and in use today. Hippocrates' ideas are expressed in The Hippocratic Corpus. The collection notes descriptions of medical philosophies and how disease and lifestyle choices reflect on the physical body. Hippocrates influenced a Westernized, professional relationship among physician and patient. Hippocrates is also known as "the Father of Medicine". Herophilos (335–280 BCE) was the first to base his conclusions on dissection of the human body and to describe the nervous system. Galen (129 – c. 200 CE) performed many audacious operations—including brain and eye surgeries— that were not tried again for almost two millennia. === Greek mathematics === In Hellenistic Egypt, the mathematician Euclid laid down the foundations of mathematical rigor and introduced the concepts of definition, axiom, theorem and proof still in use today in his Elements, considered the most influential textbook ever written. Archimedes, considered one of the greatest mathematicians of all time, is credited with using the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. He is also known in physics for laying the foundations of hydrostatics, statics, and the explanation of the principle of the lever. === Other developments === Theophrastus wrote some of the earliest descriptions of plants and animals, establishing the first taxonomy and looking at minerals in terms of their properties, such as hardness. Pliny the Elder produced one of the largest encyclopedias of the natural world in 77 CE, and was a successor to Theophrastus. For example, he accurately describes the octahedral shape of the diamond and noted that diamond dust is used by engravers to cut and polish other gems owing to its great hardness. His recognition of the importance of crystal shape is a precursor to modern crystallography, while notes on other minerals presages mineralogy. He recognizes other minerals have characteristic crystal shapes, but in one example, confuses the crystal habit with the work of lapidaries. Pliny was the first to show amber was a resin from pine trees, because of trapped insects within them. The development of archaeology has its roots in history and with those who were interested in the past, such as kings and queens who wanted to show past glories of their respective nations. The 5th-century-BCE Greek historian Herodotus was the first scholar to systematically study the past and perhaps the first to examine artifacts. === Greek scholarship under Roman rule === During the rule of Rome, famous historians such as Polybius, Livy and Plutarch documented the rise of the Roman Republic, and the organization and histories of other nations, while statesmen like Julius Caesar, Cicero, and others provided examples of the politics of the republic and Rome's empire and wars. The study of politics during this age was oriented toward understanding history, understanding methods of governing, and describing the operation of governments. The Roman conquest of Greece did not diminish learning and culture in the Greek provinces. On the contrary, the appreciation of Greek achievements in literature, philosophy, politics, and the arts by Rome's upper class coincided with the increased prosperity of the Roman Empire. Greek settlements had existed in Italy for centuries and the ability to read and speak Greek was not uncommon in Italian cities such as Rome. Moreover, the settlement of Greek scholars in Rome, whether voluntarily or as slaves, gave Romans access to teachers of Greek literature and philosophy. Conversely, young Roman scholars also studied abroad in Greece and upon their return to Rome, were able to convey Greek achievements to their Latin leadership. And despite the translation of a few Greek texts into Latin, Roman scholars who aspired to the highest level did so using the Greek language. The Roman statesman and philosopher Cicero (106 – 43 BCE) was a prime example. He had studied under Greek teachers in Rome and then in Athens and Rhodes. He mastered considerable portions of Greek philosophy, wrote Latin treatises on several topics, and even wrote Greek commentaries of Plato's Timaeus as well as a Latin translation of it, which has not survived. In the beginning, support for scholarship in Greek knowledge was almost entirely funded by the Roman upper class. There were all sorts of arrangements, ranging from a talented scholar being attached to a wealthy household to owning educated Greek-speaking slaves. In exchange, scholars who succeeded at the highest level had an obligation to provide advice or intellectual companionship to their Roman benefactors, or to even take care of their libraries. The less fortunate or accomplished ones would teach their children or perform menial tasks. The level of detail and sophistication of Greek knowledge was adjusted to suit the interests of their Roman patrons. That meant popularizing Greek knowledge by presenting information that were of practical value such as medicine or logic (for courts and politics) but excluding subtle details of Greek metaphysics and epistemology. Beyond the basics, the Romans did not value natural philosophy and considered it an amusement for leisure time. Commentaries and encyclopedias were the means by which Greek knowledge was popularized for Roman audiences. The Greek scholar Posidonius (c. 135-c. 51 BCE), a native of Syria, wrote prolifically on history, geography, moral philosophy, and natural philosophy. He greatly influenced Latin writers such as Marcus Terentius Varro (116-27 BCE), who wrote the encyclopedia Nine Books of Disciplines, which covered nine arts: grammar, rhetoric, logic, arithmetic, geometry, astronomy, musical theory, medicine, and architecture. The Disciplines became a model for subsequent Roman encyclopedias and Varro's nine liberal arts were considered suitable education for a Roman gentleman. The first seven of Varro's nine arts would later define the seven liberal arts of medieval schools. The pinnacle of the popularization movement was the Roman scholar Pliny the Elder (23/24–79 CE), a native of northern Italy, who wrote several books on the history of Rome and grammar. His most famous work was his voluminous Natural History. After the death of the Roman Emperor Marcus Aurelius in 180 CE, the favorable conditions for scholarship and learning in the Roman Empire were upended by political unrest, civil war, urban decay, and looming economic crisis. In around 250 CE, barbarians began attacking and invading the Roman frontiers. These combined events led to a general decline in political and economic conditions. The living standards of the Roman upper class was severely impacted, and their loss of leisure diminished scholarly pursuits. Moreover, during the 3rd and 4th centuries CE, the Roman Empire was administratively divided into two halves: Greek East and Latin West. These administrative divisions weakened the intellectual contact between the two regions. Eventually, both halves went their separate ways, with the Greek East becoming the Byzantine Empire. Christianity was also steadily expanding during this time and soon became a major patron of education in the Latin West. Initially, the Christian church adopted some of the reasoning tools of Greek philosophy in the 2nd and 3rd centuries CE to defend its faith against sophisticated opponents. Nevertheless, Greek philosophy received a mixed reception from leaders and adherents of the Christian faith. Some such as Tertullian (c. 155-c. 230 CE) were vehemently opposed to philosophy, denouncing it as heretic. Others such as Augustine of Hippo (354-430 CE) were ambivalent and defended Greek philosophy and science as the best ways to understand the natural world and therefore treated it as a handmaiden (or servant) of religion. Education in the West began its gradual decline, along with the rest of Western Roman Empire, due to invasions by Germanic tribes, civil unrest, and economic collapse. Contact with the classical tradition was lost in specific regions such as Roman Britain and northern Gaul but continued to exist in Rome, northern Italy, southern Gaul, Spain, and North Africa. == Middle Ages == In the Middle Ages, the classical learning continued in three major linguistic cultures and civilizations: Greek (the Byzantine Empire), Arabic (the Islamic world), and Latin (Western Europe). === Byzantine Empire === ==== Preservation of Greek heritage ==== The fall of the Western Roman Empire led to a deterioration of the classical tradition in the western part (or Latin West) of Europe during the 5th century. In contrast, the Byzantine Empire resisted the barbarian attacks and preserved and improved the learning. While the Byzantine Empire still held learning centers such as Constantinople, Alexandria and Antioch, Western Europe's knowledge was concentrated in monasteries until the development of medieval universities in the 12th centuries. The curriculum of monastic schools included the study of the few available ancient texts and of new works on practical subjects like medicine and timekeeping. In the sixth century in the Byzantine Empire, Isidore of Miletus compiled Archimedes' mathematical works in the Archimedes Palimpsest, where all Archimedes' mathematical contributions were collected and studied. John Philoponus, another Byzantine scholar, was the first to question Aristotle's teaching of physics, introducing the theory of impetus. The theory of impetus was an auxiliary or secondary theory of Aristotelian dynamics, put forth initially to explain projectile motion against gravity. It is the intellectual precursor to the concepts of inertia, momentum and acceleration in classical mechanics. The works of John Philoponus inspired Galileo Galilei ten centuries later. ==== Collapse ==== During the Fall of Constantinople in 1453, a number of Greek scholars fled to North Italy in which they fueled the era later commonly known as the "Renaissance" as they brought with them a great deal of classical learning including an understanding of botany, medicine, and zoology. Byzantium also gave the West important inputs: John Philoponus' criticism of Aristotelian physics, and the works of Dioscorides. === Islamic world === This was the period (8th–14th century CE) of the Islamic Golden Age where commerce thrived, and new ideas and technologies emerged such as the importation of papermaking from China, which made the copying of manuscripts inexpensive. ==== Translations and Hellenization ==== The eastward transmission of Greek heritage to Western Asia was a slow and gradual process that spanned over a thousand years, beginning with the Asian conquests of Alexander the Great in 335 BCE to the founding of Islam in the 7th century CE. The birth and expansion of Islam during the 7th century was quickly followed by its Hellenization. Knowledge of Greek conceptions of the world was preserved and absorbed into Islamic theology, law, culture, and commerce, which were aided by the translations of traditional Greek texts and some Syriac intermediary sources into Arabic during the 8th–9th century. ==== Education and scholarly pursuits ==== Madrasas were centers for many different religious and scientific studies and were the culmination of different institutions such as mosques based around religious studies, housing for out-of-town visitors, and finally educational institutions focused on the natural sciences. Unlike Western universities, students at a madrasa would learn from one specific teacher, who would issue a certificate at the completion of their studies called an Ijazah. An Ijazah differs from a western university degree in many ways one being that it is issued by a single person rather than an institution, and another being that it is not an individual degree declaring adequate knowledge over broad subjects, but rather a license to teach and pass on a very specific set of texts. Women were also allowed to attend madrasas, as both students and teachers, something not seen in high western education until the 1800s. Madrasas were more than just academic centers. The Suleymaniye Mosque, for example, was one of the earliest and most well-known madrasas, which was built by Suleiman the Magnificent in the 16th century. The Suleymaniye Mosque was home to a hospital and medical college, a kitchen, and children's school, as well as serving as a temporary home for travelers. Higher education at a madrasa (or college) was focused on Islamic law and religious science and students had to engage in self-study for everything else. And despite the occasional theological backlash, many Islamic scholars of science were able to conduct their work in relatively tolerant urban centers (e.g., Baghdad and Cairo) and were protected by powerful patrons. They could also travel freely and exchange ideas as there were no political barriers within the unified Islamic state. Islamic science during this time was primarily focused on the correction, extension, articulation, and application of Greek ideas to new problems. ==== Advancements in mathematics ==== Most of the achievements by Islamic scholars during this period were in mathematics. Arabic mathematics was a direct descendant of Greek and Indian mathematics. For instance, what is now known as Arabic numerals originally came from India, but Muslim mathematicians made several key refinements to the number system, such as the introduction of decimal point notation. Mathematicians such as Muhammad ibn Musa al-Khwarizmi (c. 780–850) gave his name to the concept of the algorithm, while the term algebra is derived from al-jabr, the beginning of the title of one of his publications. Islamic trigonometry continued from the works of Ptolemy's Almagest and Indian Siddhanta, from which they added trigonometric functions, drew up tables, and applied trignometry to spheres and planes. Many of their engineers, instruments makers, and surveyors contributed books in applied mathematics. It was in astronomy where Islamic mathematicians made their greatest contributions. Al-Battani (c. 858–929) improved the measurements of Hipparchus, preserved in the translation of Ptolemy's Hè Megalè Syntaxis (The great treatise) translated as Almagest. Al-Battani also improved the precision of the measurement of the precession of the Earth's axis. Corrections were made to Ptolemy's geocentric model by al-Battani, Ibn al-Haytham, Averroes and the Maragha astronomers such as Nasir al-Din al-Tusi, Mu'ayyad al-Din al-Urdi and Ibn al-Shatir. Scholars with geometric skills made significant improvements to the earlier classical texts on light and sight by Euclid, Aristotle, and Ptolemy. The earliest surviving Arabic treatises were written in the 9th century by Abū Ishāq al-Kindī, Qustā ibn Lūqā, and (in fragmentary form) Ahmad ibn Isā. Later in the 11th century, Ibn al-Haytham (known as Alhazen in the West), a mathematician and astronomer, synthesized a new theory of vision based on the works of his predecessors. His new theory included a complete system of geometrical optics, which was set in great detail in his Book of Optics. His book was translated into Latin and was relied upon as a principal source on the science of optics in Europe until the 17th century. ==== Institutionalization of medicine ==== The medical sciences were prominently cultivated in the Islamic world. The works of Greek medical theories, especially those of Galen, were translated into Arabic and there was an outpouring of medical texts by Islamic physicians, which were aimed at organizing, elaborating, and disseminating classical medical knowledge. Medical specialties started to emerge, such as those involved in the treatment of eye diseases such as cataracts. Ibn Sina (known as Avicenna in the West, c. 980–1037) was a prolific Persian medical encyclopedist wrote extensively on medicine, with his two most notable works in medicine being the Kitāb al-shifāʾ ("Book of Healing") and The Canon of Medicine, both of which were used as standard medicinal texts in both the Muslim world and in Europe well into the 17th century. Amongst his many contributions are the discovery of the contagious nature of infectious diseases, and the introduction of clinical pharmacology. Institutionalization of medicine was another important achievement in the Islamic world. Although hospitals as an institution for the sick emerged in the Byzantium empire, the model of institutionalized medicine for all social classes was extensive in the Islamic empire and was scattered throughout. In addition to treating patients, physicians could teach apprentice physicians, as well write and do research. The discovery of the pulmonary transit of blood in the human body by Ibn al-Nafis occurred in a hospital setting. ==== Decline ==== Islamic science began its decline in the 12th–13th century, before the Renaissance in Europe, due in part to the Christian reconquest of Spain and the Mongol conquests in the East in the 11th–13th century. The Mongols sacked Baghdad, capital of the Abbasid Caliphate, in 1258, which ended the Abbasid empire. Nevertheless, many of the conquerors became patrons of the sciences. Hulagu Khan, for example, who led the siege of Baghdad, became a patron of the Maragheh observatory. Islamic astronomy continued to flourish into the 16th century. === Western Europe === By the eleventh century, most of Europe had become Christian; stronger monarchies emerged; borders were restored; technological developments and agricultural innovations were made, increasing the food supply and population. Classical Greek texts were translated from Arabic and Greek into Latin, stimulating scientific discussion in Western Europe. In classical antiquity, Greek and Roman taboos had meant that dissection was usually banned, but in the Middle Ages medical teachers and students at Bologna began to open human bodies, and Mondino de Luzzi (c. 1275–1326) produced the first known anatomy textbook based on human dissection. As a result of the Pax Mongolica, Europeans, such as Marco Polo, began to venture further and further east. The written accounts of Polo and his fellow travelers inspired other Western European maritime explorers to search for a direct sea route to Asia, ultimately leading to the Age of Discovery. Technological advances were also made, such as the early flight of Eilmer of Malmesbury (who had studied mathematics in 11th-century England), and the metallurgical achievements of the Cistercian blast furnace at Laskill. ==== Medieval universities ==== An intellectual revitalization of Western Europe started with the birth of medieval universities in the 12th century. These urban institutions grew from the informal scholarly activities of learned friars who visited monasteries, consulted libraries, and conversed with other fellow scholars. A friar who became well-known would attract a following of disciples, giving rise to a brotherhood of scholars (or collegium in Latin). A collegium might travel to a town or request a monastery to host them. However, if the number of scholars within a collegium grew too large, they would opt to settle in a town instead. As the number of collegia within a town grew, the collegia might request that their king grant them a charter that would convert them into a universitas. Many universities were chartered during this period, with the first in Bologna in 1088, followed by Paris in 1150, Oxford in 1167, and Cambridge in 1231. The granting of a charter meant that the medieval universities were partially sovereign and independent from local authorities. Their independence allowed them to conduct themselves and judge their own members based on their own rules. Furthermore, as initially religious institutions, their faculties and students were protected from capital punishment (e.g., gallows). Such independence was a matter of custom, which could, in principle, be revoked by their respective rulers if they felt threatened. Discussions of various subjects or claims at these medieval institutions, no matter how controversial, were done in a formalized way so as to declare such discussions as being within the bounds of a university and therefore protected by the privileges of that institution's sovereignty. A claim could be described as ex cathedra (literally "from the chair", used within the context of teaching) or ex hypothesi (by hypothesis). This meant that the discussions were presented as purely an intellectual exercise that did not require those involved to commit themselves to the truth of a claim or to proselytize. Modern academic concepts and practices such as academic freedom or freedom of inquiry are remnants of these medieval privileges that were tolerated in the past. The curriculum of these medieval institutions centered on the seven liberal arts, which were aimed at providing beginning students with the skills for reasoning and scholarly language. Students would begin their studies starting with the first three liberal arts or Trivium (grammar, rhetoric, and logic) followed by the next four liberal arts or Quadrivium (arithmetic, geometry, astronomy, and music). Those who completed these requirements and received their baccalaureate (or Bachelor of Arts) had the option to join the higher faculty (law, medicine, or theology), which would confer an LLD for a lawyer, an MD for a physician, or ThD for a theologian. Students who chose to remain in the lower faculty (arts) could work towards a Magister (or Master's) degree and would study three philosophies: metaphysics, ethics, and natural philosophy. Latin translations of Aristotle's works such as De Anima (On the Soul) and the commentaries on them were required readings. As time passed, the lower faculty was allowed to confer its own doctoral degree called the PhD. Many of the Masters were drawn to encyclopedias and had used them as textbooks. But these scholars yearned for the complete original texts of the Ancient Greek philosophers, mathematicians, and physicians such as Aristotle, Euclid, and Galen, which were not available to them at the time. These Ancient Greek texts were to be found in the Byzantine Empire and the Islamic World. ==== Translations of Greek and Arabic sources ==== Contact with the Byzantine Empire, and with the Islamic world during the Reconquista and the Crusades, allowed Latin Europe access to scientific Greek and Arabic texts, including the works of Aristotle, Ptolemy, Isidore of Miletus, John Philoponus, Jābir ibn Hayyān, al-Khwarizmi, Alhazen, Avicenna, and Averroes. European scholars had access to the translation programs of Raymond of Toledo, who sponsored the 12th century Toledo School of Translators from Arabic to Latin. Later translators like Michael Scotus would learn Arabic in order to study these texts directly. The European universities aided materially in the translation and propagation of these texts and started a new infrastructure which was needed for scientific communities. In fact, European university put many works about the natural world and the study of nature at the center of its curriculum, with the result that the "medieval university laid far greater emphasis on science than does its modern counterpart and descendent." At the beginning of the 13th century, there were reasonably accurate Latin translations of the main works of almost all the intellectually crucial ancient authors, allowing a sound transfer of scientific ideas via both the universities and the monasteries. By then, the natural philosophy in these texts began to be extended by scholastics such as Robert Grosseteste, Roger Bacon, Albertus Magnus and Duns Scotus. Precursors of the modern scientific method, influenced by earlier contributions of the Islamic world, can be seen already in Grosseteste's emphasis on mathematics as a way to understand nature, and in the empirical approach admired by Bacon, particularly in his Opus Majus. Pierre Duhem's thesis is that Stephen Tempier – the Bishop of Paris – Condemnation of 1277 led to the study of medieval science as a serious discipline, "but no one in the field any longer endorses his view that modern science started in 1277". However, many scholars agree with Duhem's view that the mid-late Middle Ages saw important scientific developments. ==== Medieval science ==== The first half of the 14th century saw much important scientific work, largely within the framework of scholastic commentaries on Aristotle's scientific writings. William of Ockham emphasized the principle of parsimony: natural philosophers should not postulate unnecessary entities, so that motion is not a distinct thing but is only the moving object and an intermediary "sensible species" is not needed to transmit an image of an object to the eye. Scholars such as Jean Buridan and Nicole Oresme started to reinterpret elements of Aristotle's mechanics. In particular, Buridan developed the theory that impetus was the cause of the motion of projectiles, which was a first step towards the modern concept of inertia. The Oxford Calculators began to mathematically analyze the kinematics of motion, making this analysis without considering the causes of motion. In 1348, the Black Death and other disasters sealed a sudden end to philosophic and scientific development. Yet, the rediscovery of ancient texts was stimulated by the Fall of Constantinople in 1453, when many Byzantine scholars sought refuge in the West. Meanwhile, the introduction of printing was to have great effect on European society. The facilitated dissemination of the printed word democratized learning and allowed ideas such as algebra to propagate more rapidly. These developments paved the way for the Scientific Revolution, where scientific inquiry, halted at the start of the Black Death, resumed. == Renaissance == === Revival of learning === The renewal of learning in Europe began with 12th century Scholasticism. The Northern Renaissance showed a decisive shift in focus from Aristotelian natural philosophy to chemistry and the biological sciences (botany, anatomy, and medicine). Thus modern science in Europe was resumed in a period of great upheaval: the Protestant Reformation and Catholic Counter-Reformation; the discovery of the Americas by Christopher Columbus; the Fall of Constantinople; but also the re-discovery of Aristotle during the Scholastic period presaged large social and political changes. Thus, a suitable environment was created in which it became possible to question scientific doctrine, in much the same way that Martin Luther and John Calvin questioned religious doctrine. The works of Ptolemy (astronomy) and Galen (medicine) were found not always to match everyday observations. Work by Vesalius on human cadavers found problems with the Galenic view of anatomy. The discovery of Cristallo contributed to the advancement of science in the period as well with its appearance out of Venice around 1450. The new glass allowed for better spectacles and eventually to the inventions of the telescope and microscope. Theophrastus' work on rocks, Peri lithōn, remained authoritative for millennia: its interpretation of fossils was not overturned until after the Scientific Revolution. During the Italian Renaissance, Niccolò Machiavelli established the emphasis of modern political science on direct empirical observation of political institutions and actors. Later, the expansion of the scientific paradigm during the Enlightenment further pushed the study of politics beyond normative determinations. In particular, the study of statistics, to study the subjects of the state, has been applied to polling and voting. In archaeology, the 15th and 16th centuries saw the rise of antiquarians in Renaissance Europe who were interested in the collection of artifacts. === Scientific Revolution and birth of New Science === The early modern period is seen as a flowering of the European Renaissance. There was a willingness to question previously held truths and search for new answers. This resulted in a period of major scientific advancements, now known as the Scientific Revolution, which led to the emergence of a New Science that was more mechanistic in its worldview, more integrated with mathematics, and more reliable and open as its knowledge was based on a newly defined scientific method. The Scientific Revolution is a convenient boundary between ancient thought and classical physics, and is traditionally held to have begun in 1543, when the books De humani corporis fabrica (On the Workings of the Human Body) by Andreas Vesalius, and also De Revolutionibus, by the astronomer Nicolaus Copernicus, were first printed. The period culminated with the publication of the Philosophiæ Naturalis Principia Mathematica in 1687 by Isaac Newton, representative of the unprecedented growth of scientific publications throughout Europe. Other significant scientific advances were made during this time by Galileo Galilei, Johannes Kepler, Edmond Halley, William Harvey, Pierre Fermat, Robert Hooke, Christiaan Huygens, Tycho Brahe, Marin Mersenne, Gottfried Leibniz, Isaac Newton, and Blaise Pascal. In philosophy, major contributions were made by Francis Bacon, Sir Thomas Browne, René Descartes, Baruch Spinoza, Pierre Gassendi, Robert Boyle, and Thomas Hobbes. Christiaan Huygens derived the centripetal and centrifugal forces and was the first to transfer mathematical inquiry to describe unobservable physical phenomena. William Gilbert did some of the earliest experiments with electricity and magnetism, establishing that the Earth itself is magnetic. ==== Heliocentrism ==== The heliocentric astronomical model of the universe was refined by Nicolaus Copernicus. Copernicus proposed the idea that the Earth and all heavenly spheres, containing the planets and other objects in the cosmos, rotated around the Sun. His heliocentric model also proposed that all stars were fixed and did not rotate on an axis, nor in any motion at all. His theory proposed the yearly rotation of the Earth and the other heavenly spheres around the Sun and was able to calculate the distances of planets using deferents and epicycles. Although these calculations were not completely accurate, Copernicus was able to understand the distance order of each heavenly sphere. The Copernican heliocentric system was a revival of the hypotheses of Aristarchus of Samos and Seleucus of Seleucia. Aristarchus of Samos did propose that the Earth rotated around the Sun but did not mention anything about the other heavenly spheres' order, motion, or rotation. Seleucus of Seleucia also proposed the rotation of the Earth around the Sun but did not mention anything about the other heavenly spheres. In addition, Seleucus of Seleucia understood that the Moon rotated around the Earth and could be used to explain the tides of the oceans, thus further proving his understanding of the heliocentric idea. == Age of Enlightenment == === Continuation of Scientific Revolution === The Scientific Revolution continued into the Age of Enlightenment, which accelerated the development of modern science. ==== Planets and orbits ==== The heliocentric model revived by Nicolaus Copernicus was followed by the model of planetary motion given by Johannes Kepler in the early 17th century, which proposed that the planets follow elliptical orbits, with the Sun at one focus of the ellipse. In Astronomia Nova (A New Astronomy), the first two of the laws of planetary motion were shown by the analysis of the orbit of Mars. Kepler introduced the revolutionary concept of planetary orbit. Because of his work astronomical phenomena came to be seen as being governed by physical laws. ==== Emergence of chemistry ==== A decisive moment came when "chemistry" was distinguished from alchemy by Robert Boyle in his work The Sceptical Chymist, in 1661; although the alchemical tradition continued for some time after his work. Other important steps included the gravimetric experimental practices of medical chemists like William Cullen, Joseph Black, Torbern Bergman and Pierre Macquer and through the work of Antoine Lavoisier ("father of modern chemistry") on oxygen and the law of conservation of mass, which refuted phlogiston theory. Modern chemistry emerged from the sixteenth through the eighteenth centuries through the material practices and theories promoted by alchemy, medicine, manufacturing and mining. ==== Calculus and Newtonian mechanics ==== In 1687, Isaac Newton published the Principia Mathematica, detailing two comprehensive and successful physical theories: Newton's laws of motion, which led to classical mechanics; and Newton's law of universal gravitation, which describes the fundamental force of gravity. ==== Circulatory system ==== William Harvey published De Motu Cordis in 1628, which revealed his conclusions based on his extensive studies of vertebrate circulatory systems. He identified the central role of the heart, arteries, and veins in producing blood movement in a circuit, and failed to find any confirmation of Galen's pre-existing notions of heating and cooling functions. The history of early modern biology and medicine is often told through the search for the seat of the soul. Galen in his descriptions of his foundational work in medicine presents the distinctions between arteries, veins, and nerves using the vocabulary of the soul. ==== Scientific societies and journals ==== A critical innovation was the creation of permanent scientific societies and their scholarly journals, which dramatically sped the diffusion of new ideas. Typical was the founding of the Royal Society in London in 1660 and its journal in 1665 the Philosophical Transaction of the Royal Society, the first scientific journal in English. 1665 also saw the first journal in French, the Journal des sçavans. Science drawing on the works of Newton, Descartes, Pascal and Leibniz, science was on a path to modern mathematics, physics and technology by the time of the generation of Benjamin Franklin (1706–1790), Leonhard Euler (1707–1783), Mikhail Lomonosov (1711–1765) and Jean le Rond d'Alembert (1717–1783). Denis Diderot's Encyclopédie, published between 1751 and 1772 brought this new understanding to a wider audience. The impact of this process was not limited to science and technology, but affected philosophy (Immanuel Kant, David Hume), religion (the increasingly significant impact of science upon religion), and society and politics in general (Adam Smith, Voltaire). ==== Developments in geology ==== Geology did not undergo systematic restructuring during the Scientific Revolution but instead existed as a cloud of isolated, disconnected ideas about rocks, minerals, and landforms long before it became a coherent science. Robert Hooke formulated a theory of earthquakes, and Nicholas Steno developed the theory of superposition and argued that fossils were the remains of once-living creatures. Beginning with Thomas Burnet's Sacred Theory of the Earth in 1681, natural philosophers began to explore the idea that the Earth had changed over time. Burnet and his contemporaries interpreted Earth's past in terms of events described in the Bible, but their work laid the intellectual foundations for secular interpretations of Earth history. === Post-Scientific Revolution === ==== Bioelectricity ==== During the late 18th century, researchers such as Hugh Williamson and John Walsh experimented on the effects of electricity on the human body. Further studies by Luigi Galvani and Alessandro Volta established the electrical nature of what Volta called galvanism. ==== Developments in geology ==== Modern geology, like modern chemistry, gradually evolved during the 18th and early 19th centuries. Benoît de Maillet and the Comte de Buffon saw the Earth as much older than the 6,000 years envisioned by biblical scholars. Jean-Étienne Guettard and Nicolas Desmarest hiked central France and recorded their observations on some of the first geological maps. Aided by chemical experimentation, naturalists such as Scotland's John Walker, Sweden's Torbern Bergman, and Germany's Abraham Werner created comprehensive classification systems for rocks and minerals—a collective achievement that transformed geology into a cutting edge field by the end of the eighteenth century. These early geologists also proposed a generalized interpretations of Earth history that led James Hutton, Georges Cuvier and Alexandre Brongniart, following in the steps of Steno, to argue that layers of rock could be dated by the fossils they contained: a principle first applied to the geology of the Paris Basin. The use of index fossils became a powerful tool for making geological maps, because it allowed geologists to correlate the rocks in one locality with those of similar age in other, distant localities. ==== Birth of modern economics ==== The basis for classical economics forms Adam Smith's An Inquiry into the Nature and Causes of the Wealth of Nations, published in 1776. Smith criticized mercantilism, advocating a system of free trade with division of labour. He postulated an "invisible hand" that regulated economic systems made up of actors guided only by self-interest. The "invisible hand" mentioned in a lost page in the middle of a chapter in the middle of the "Wealth of Nations", 1776, advances as Smith's central message. ==== Social science ==== Anthropology can best be understood as an outgrowth of the Age of Enlightenment. It was during this period that Europeans attempted systematically to study human behavior. Traditions of jurisprudence, history, philology and sociology developed during this time and informed the development of the social sciences of which anthropology was a part. == 19th century == The 19th century saw the birth of science as a profession. William Whewell had coined the term scientist in 1833, which soon replaced the older term natural philosopher. === Developments in physics === In physics, the behavior of electricity and magnetism was studied by Giovanni Aldini, Alessandro Volta, Michael Faraday, Georg Ohm, and others. The experiments, theories and discoveries of Michael Faraday, Andre-Marie Ampere, James Clerk Maxwell, and their contemporaries led to the unification of the two phenomena into a single theory of electromagnetism as described by Maxwell's equations. Thermodynamics led to an understanding of heat and the notion of energy being defined. === Discovery of Neptune === In astronomy, the planet Neptune was discovered. Advances in astronomy and in optical systems in the 19th century resulted in the first observation of an asteroid (1 Ceres) in 1801, and the discovery of Neptune in 1846. === Developments in mathematics === In mathematics, the notion of complex numbers finally matured and led to a subsequent analytical theory; they also began the use of hypercomplex numbers. Karl Weierstrass and others carried out the arithmetization of analysis for functions of real and complex variables. It also saw rise to new progress in geometry beyond those classical theories of Euclid, after a period of nearly two thousand years. The mathematical science of logic likewise had revolutionary breakthroughs after a similarly long period of stagnation. But the most important step in science at this time were the ideas formulated by the creators of electrical science. Their work changed the face of physics and made possible for new technology to come about such as electric power, electrical telegraphy, the telephone, and radio. === Developments in chemistry === In chemistry, Dmitri Mendeleev, following the atomic theory of John Dalton, created the first periodic table of elements. Other highlights include the discoveries unveiling the nature of atomic structure and matter, simultaneously with chemistry – and of new kinds of radiation. The theory that all matter is made of atoms, which are the smallest constituents of matter that cannot be broken down without losing the basic chemical and physical properties of that matter, was provided by John Dalton in 1803, although the question took a hundred years to settle as proven. Dalton also formulated the law of mass relationships. In 1869, Dmitri Mendeleev composed his periodic table of elements on the basis of Dalton's discoveries. The synthesis of urea by Friedrich Wöhler opened a new research field, organic chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The later part of the 19th century saw the exploitation of the Earth's petrochemicals, after the exhaustion of the oil supply from whaling. By the 20th century, systematic production of refined materials provided a ready supply of products which provided not only energy, but also synthetic materials for clothing, medicine, and everyday disposable resources. Application of the techniques of organic chemistry to living organisms resulted in physiological chemistry, the precursor to biochemistry. === Age of the Earth === Over the first half of the 19th century, geologists such as Charles Lyell, Adam Sedgwick, and Roderick Murchison applied the new technique to rocks throughout Europe and eastern North America, setting the stage for more detailed, government-funded mapping projects in later decades. Midway through the 19th century, the focus of geology shifted from description and classification to attempts to understand how the surface of the Earth had changed. The first comprehensive theories of mountain building were proposed during this period, as were the first modern theories of earthquakes and volcanoes. Louis Agassiz and others established the reality of continent-covering ice ages, and "fluvialists" like Andrew Crombie Ramsay argued that river valleys were formed, over millions of years by the rivers that flow through them. After the discovery of radioactivity, radiometric dating methods were developed, starting in the 20th century. Alfred Wegener's theory of "continental drift" was widely dismissed when he proposed it in the 1910s, but new data gathered in the 1950s and 1960s led to the theory of plate tectonics, which provided a plausible mechanism for it. Plate tectonics also provided a unified explanation for a wide range of seemingly unrelated geological phenomena. Since the 1960s it has served as the unifying principle in geology. === Evolution and inheritance === Perhaps the most prominent, controversial, and far-reaching theory in all of science has been the theory of evolution by natural selection, which was independently formulated by Charles Darwin and Alfred Wallace. It was described in detail in Darwin's book The Origin of Species, which was published in 1859. In it, Darwin proposed that the features of all living things, including humans, were shaped by natural processes over long periods of time. The theory of evolution in its current form affects almost all areas of biology. Implications of evolution on fields outside of pure science have led to both opposition and support from different parts of society, and profoundly influenced the popular understanding of "man's place in the universe". Separately, Gregor Mendel formulated the principles of inheritance in 1866, which became the basis of modern genetics. === Germ theory === Another important landmark in medicine and biology were the successful efforts to prove the germ theory of disease. Following this, Louis Pasteur made the first vaccine against rabies, and also made many discoveries in the field of chemistry, including the asymmetry of crystals. In 1847, Hungarian physician Ignác Fülöp Semmelweis dramatically reduced the occurrence of puerperal fever by simply requiring physicians to wash their hands before attending to women in childbirth. This discovery predated the germ theory of disease. However, Semmelweis' findings were not appreciated by his contemporaries and handwashing came into use only with discoveries by British surgeon Joseph Lister, who in 1865 proved the principles of antisepsis. Lister's work was based on the important findings by French biologist Louis Pasteur. Pasteur was able to link microorganisms with disease, revolutionizing medicine. He also devised one of the most important methods in preventive medicine, when in 1880 he produced a vaccine against rabies. Pasteur invented the process of pasteurization, to help prevent the spread of disease through milk and other foods. === Schools of economics === Karl Marx developed an alternative economic theory, called Marxian economics. Marxian economics is based on the labor theory of value and assumes the value of good to be based on the amount of labor required to produce it. Under this axiom, capitalism was based on employers not paying the full value of workers labor to create profit. The Austrian School responded to Marxian economics by viewing entrepreneurship as driving force of economic development. This replaced the labor theory of value by a system of supply and demand. === Founding of psychology === Psychology as a scientific enterprise that was independent from philosophy began in 1879 when Wilhelm Wundt founded the first laboratory dedicated exclusively to psychological research (in Leipzig). Other important early contributors to the field include Hermann Ebbinghaus (a pioneer in memory studies), Ivan Pavlov (who discovered classical conditioning), William James, and Sigmund Freud. Freud's influence has been enormous, though more as cultural icon than a force in scientific psychology. === Modern sociology === Modern sociology emerged in the early 19th century as the academic response to the modernization of the world. Among many early sociologists (e.g., Émile Durkheim), the aim of sociology was in structuralism, understanding the cohesion of social groups, and developing an "antidote" to social disintegration. Max Weber was concerned with the modernization of society through the concept of rationalization, which he believed would trap individuals in an "iron cage" of rational thought. Some sociologists, including Georg Simmel and W. E. B. Du Bois, used more microsociological, qualitative analyses. This microlevel approach played an important role in American sociology, with the theories of George Herbert Mead and his student Herbert Blumer resulting in the creation of the symbolic interactionism approach to sociology. In particular, just Auguste Comte, illustrated with his work the transition from a theological to a metaphysical stage and, from this, to a positive stage. Comte took care of the classification of the sciences as well as a transit of humanity towards a situation of progress attributable to a re-examination of nature according to the affirmation of 'sociality' as the basis of the scientifically interpreted society. === Romanticism === The Romantic Movement of the early 19th century reshaped science by opening up new pursuits unexpected in the classical approaches of the Enlightenment. The decline of Romanticism occurred because a new movement, Positivism, began to take hold of the ideals of the intellectuals after 1840 and lasted until about 1880. At the same time, the romantic reaction to the Enlightenment produced thinkers such as Johann Gottfried Herder and later Wilhelm Dilthey whose work formed the basis for the culture concept which is central to the discipline. Traditionally, much of the history of the subject was based on colonial encounters between Western Europe and the rest of the world, and much of 18th- and 19th-century anthropology is now classed as scientific racism. During the late 19th century, battles over the "study of man" took place between those of an "anthropological" persuasion (relying on anthropometrical techniques) and those of an "ethnological" persuasion (looking at cultures and traditions), and these distinctions became part of the later divide between physical anthropology and cultural anthropology, the latter ushered in by the students of Franz Boas. == 20th century == Science advanced dramatically during the 20th century. There were new and radical developments in the physical and life sciences, building on the progress from the 19th century. === Theory of relativity and quantum mechanics === The beginning of the 20th century brought the start of a revolution in physics. The long-held theories of Newton were shown not to be correct in all circumstances. Beginning in 1900, Max Planck, Albert Einstein, Niels Bohr and others developed quantum theories to explain various anomalous experimental results, by introducing discrete energy levels. Not only did quantum mechanics show that the laws of motion did not hold on small scales, but the theory of general relativity, proposed by Einstein in 1915, showed that the fixed background of spacetime, on which both Newtonian mechanics and special relativity depended, could not exist. In 1925, Werner Heisenberg and Erwin Schrödinger formulated quantum mechanics, which explained the preceding quantum theories. Currently, general relativity and quantum mechanics are inconsistent with each other, and efforts are underway to unify the two. === Big Bang === The observation by Edwin Hubble in 1929 that the speed at which galaxies recede positively correlates with their distance, led to the understanding that the universe is expanding, and the formulation of the Big Bang theory by Georges Lemaître. George Gamow, Ralph Alpher, and Robert Herman had calculated that there should be evidence for a Big Bang in the background temperature of the universe. In 1964, Arno Penzias and Robert Wilson discovered a 3 Kelvin background hiss in their Bell Labs radiotelescope (the Holmdel Horn Antenna), which was evidence for this hypothesis, and formed the basis for a number of results that helped determine the age of the universe. === Big science === In 1938 Otto Hahn and Fritz Strassmann discovered nuclear fission with radiochemical methods, and in 1939 Lise Meitner and Otto Robert Frisch wrote the first theoretical interpretation of the fission process, which was later improved by Niels Bohr and John A. Wheeler. Further developments took place during World War II, which led to the practical application of radar and the development and use of the atomic bomb. Around this time, Chien-Shiung Wu was recruited by the Manhattan Project to help develop a process for separating uranium metal into U-235 and U-238 isotopes by Gaseous diffusion. She was an expert experimentalist in beta decay and weak interaction physics. Wu designed an experiment (see Wu experiment) that enabled theoretical physicists Tsung-Dao Lee and Chen-Ning Yang to disprove the law of parity experimentally, winning them a Nobel Prize in 1957. Though the process had begun with the invention of the cyclotron by Ernest O. Lawrence in the 1930s, physics in the postwar period entered into a phase of what historians have called "Big Science", requiring massive machines, budgets, and laboratories in order to test their theories and move into new frontiers. The primary patron of physics became state governments, who recognized that the support of "basic" research could often lead to technologies useful to both military and industrial applications. === Advances in genetics === In the early 20th century, the study of heredity became a major investigation after the rediscovery in 1900 of the laws of inheritance developed by Mendel. The 20th century also saw the integration of physics and chemistry, with chemical properties explained as the result of the electronic structure of the atom. Linus Pauling's book on The Nature of the Chemical Bond used the principles of quantum mechanics to deduce bond angles in ever-more complicated molecules. Pauling's work culminated in the physical modelling of DNA, the secret of life (in the words of Francis Crick, 1953). In the same year, the Miller–Urey experiment demonstrated in a simulation of primordial processes, that basic constituents of proteins, simple amino acids, could themselves be built up from simpler molecules, kickstarting decades of research into the chemical origins of life. By 1953, James D. Watson and Francis Crick clarified the basic structure of DNA, the genetic material for expressing life in all its forms, building on the work of Maurice Wilkins and Rosalind Franklin, suggested that the structure of DNA was a double helix. In their famous paper "Molecular structure of Nucleic Acids" In the late 20th century, the possibilities of genetic engineering became practical for the first time, and a massive international effort began in 1990 to map out an entire human genome (the Human Genome Project). The discipline of ecology typically traces its origin to the synthesis of Darwinian evolution and Humboldtian biogeography, in the late 19th and early 20th centuries. Equally important in the rise of ecology, however, were microbiology and soil science—particularly the cycle of life concept, prominent in the work of Louis Pasteur and Ferdinand Cohn. The word ecology was coined by Ernst Haeckel, whose particularly holistic view of nature in general (and Darwin's theory in particular) was important in the spread of ecological thinking. The field of ecosystem ecology emerged in the Atomic Age with the use of radioisotopes to visualize food webs and by the 1970s ecosystem ecology deeply influenced global environmental management. === Space exploration === In 1925, Cecilia Payne-Gaposchkin determined that stars were composed mostly of hydrogen and helium. She was dissuaded by astronomer Henry Norris Russell from publishing this finding in her PhD thesis because of the widely held belief that stars had the same composition as the Earth. However, four years later, in 1929, Henry Norris Russell came to the same conclusion through different reasoning and the discovery was eventually accepted. In 1987, supernova SN 1987A was observed by astronomers on Earth both visually, and in a triumph for neutrino astronomy, by the solar neutrino detectors at Kamiokande. But the solar neutrino flux was a fraction of its theoretically expected value. This discrepancy forced a change in some values in the standard model for particle physics. === Neuroscience as a distinct discipline === The understanding of neurons and the nervous system became increasingly precise and molecular during the 20th century. For example, in 1952, Alan Lloyd Hodgkin and Andrew Huxley presented a mathematical model for transmission of electrical signals in neurons of the giant axon of a squid, which they called "action potentials", and how they are initiated and propagated, known as the Hodgkin–Huxley model. In 1961–1962, Richard FitzHugh and J. Nagumo simplified Hodgkin–Huxley, in what is called the FitzHugh–Nagumo model. In 1962, Bernard Katz modeled neurotransmission across the space between neurons known as synapses. Beginning in 1966, Eric Kandel and collaborators examined biochemical changes in neurons associated with learning and memory storage in Aplysia. In 1981 Catherine Morris and Harold Lecar combined these models in the Morris–Lecar model. Such increasingly quantitative work gave rise to numerous biological neuron models and models of neural computation. Neuroscience began to be recognized as a distinct academic discipline in its own right. Eric Kandel and collaborators have cited David Rioch, Francis O. Schmitt, and Stephen Kuffler as having played critical roles in establishing the field. === Plate tectonics === Geologists' embrace of plate tectonics became part of a broadening of the field from a study of rocks into a study of the Earth as a planet. Other elements of this transformation include: geophysical studies of the interior of the Earth, the grouping of geology with meteorology and oceanography as one of the "earth sciences", and comparisons of Earth and the solar system's other rocky planets. === Applications === In terms of applications, a massive number of new technologies were developed in the 20th century. Technologies such as electricity, the incandescent light bulb, the automobile and the phonograph, first developed at the end of the 19th century, were perfected and universally deployed. The first car was introduced by Karl Benz in 1885. The first airplane flight occurred in 1903, and by the end of the century airliners flew thousands of miles in a matter of hours. The development of the radio, television and computers caused massive changes in the dissemination of information. Advances in biology also led to large increases in food production, as well as the elimination of diseases such as polio by Dr. Jonas Salk. Gene mapping and gene sequencing, invented by Drs. Mark Skolnik and Walter Gilbert, respectively, are the two technologies that made the Human Genome Project feasible. Computer science, built upon a foundation of theoretical linguistics, discrete mathematics, and electrical engineering, studies the nature and limits of computation. Subfields include computability, computational complexity, database design, computer networking, artificial intelligence, and the design of computer hardware. One area in which advances in computing have contributed to more general scientific development is by facilitating large-scale archiving of scientific data. Contemporary computer science typically distinguishes itself by emphasizing mathematical 'theory' in contrast to the practical emphasis of software engineering. Einstein's paper "On the Quantum Theory of Radiation" outlined the principles of the stimulated emission of photons. This led to the invention of the Laser (light amplification by the stimulated emission of radiation) and the optical amplifier which ushered in the Information Age. It is optical amplification that allows fiber optic networks to transmit the massive capacity of the Internet. Based on wireless transmission of electromagnetic radiation and global networks of cellular operation, the mobile phone became a primary means to access the internet. === Developments in political science and economics === In political science during the 20th century, the study of ideology, behaviouralism and international relations led to a multitude of 'pol-sci' subdisciplines including rational choice theory, voting theory, game theory (also used in economics), psephology, political geography/geopolitics, political anthropology/political psychology/political sociology, political economy, policy analysis, public administration, comparative political analysis and peace studies/conflict analysis. In economics, John Maynard Keynes prompted a division between microeconomics and macroeconomics in the 1920s. Under Keynesian economics macroeconomic trends can overwhelm economic choices made by individuals. Governments should promote aggregate demand for goods as a means to encourage economic expansion. Following World War II, Milton Friedman created the concept of monetarism. Monetarism focuses on using the supply and demand of money as a method for controlling economic activity. In the 1970s, monetarism has adapted into supply-side economics which advocates reducing taxes as a means to increase the amount of money available for economic expansion. Other modern schools of economic thought are New Classical economics and New Keynesian economics. New Classical economics was developed in the 1970s, emphasizing solid microeconomics as the basis for macroeconomic growth. New Keynesian economics was created partially in response to New Classical economics. It shows how imperfect competition and market rigidities, means monetary policy has real effects, and enables analysis of different policies. === Developments in psychology, sociology, and anthropology === Psychology in the 20th century saw a rejection of Freud's theories as being too unscientific, and a reaction against Edward Titchener's atomistic approach of the mind. This led to the formulation of behaviorism by John B. Watson, which was popularized by B.F. Skinner. Behaviorism proposed epistemologically limiting psychological study to overt behavior, since that could be reliably measured. Scientific knowledge of the "mind" was considered too metaphysical, hence impossible to achieve. The final decades of the 20th century have seen the rise of cognitive science, which considers the mind as once again a subject for investigation, using the tools of psychology, linguistics, computer science, philosophy, and neurobiology. New methods of visualizing the activity of the brain, such as PET scans and CAT scans, began to exert their influence as well, leading some researchers to investigate the mind by investigating the brain, rather than cognition. These new forms of investigation assume that a wide understanding of the human mind is possible, and that such an understanding may be applied to other research domains, such as artificial intelligence. Evolutionary theory was applied to behavior and introduced to anthropology and psychology, through the works of cultural anthropologist Napoleon Chagnon. Physical anthropology would become biological anthropology, incorporating elements of evolutionary biology. American sociology in the 1940s and 1950s was dominated largely by Talcott Parsons, who argued that aspects of society that promoted structural integration were therefore "functional". This structural functionalism approach was questioned in the 1960s, when sociologists came to see this approach as merely a justification for inequalities present in the status quo. In reaction, conflict theory was developed, which was based in part on the philosophies of Karl Marx. Conflict theorists saw society as an arena in which different groups compete for control over resources. Symbolic interactionism also came to be regarded as central to sociological thinking. Erving Goffman saw social interactions as a stage performance, with individuals preparing "backstage" and attempting to control their audience through impression management. While these theories are currently prominent in sociological thought, other approaches exist, including feminist theory, post-structuralism, rational choice theory, and postmodernism. In the mid-20th century, much of the methodologies of earlier anthropological and ethnographical study were reevaluated with an eye towards research ethics, while at the same time the scope of investigation has broadened far beyond the traditional study of "primitive cultures". == 21st century == In the early 21st century, some concepts that originated in 20th century physics were proven. On 4 July 2012, physicists working at CERN's Large Hadron Collider announced that they had discovered a new subatomic particle greatly resembling the Higgs boson, confirmed as such by the following March. Gravitational waves were first detected on 14 September 2015. The Human Genome Project was declared complete in 2003. The CRISPR gene editing technique developed in 2012 allowed scientists to precisely and easily modify DNA and led to the development of new medicine. In 2020, xenobots, a new class of living robotics, were invented; reproductive capabilities were introduced the following year. Positive psychology is a branch of psychology founded in 1998 by Martin Seligman that is concerned with the study of happiness, mental well-being, and positive human functioning, and is a reaction to 20th century psychology's emphasis on mental illness and dysfunction. == See also == == References == === Sources === Bruno, Leonard C. (1989). The Landmarks of Science. Facts on File. ISBN 978-0-8160-2137-6. Heilbron, John L., ed. (2003). The Oxford Companion to the History of Modern Science. Oxford University Press. ISBN 978-0-19-511229-0. Needham, Joseph; Wang, Ling (1954). Introductory Orientations. Science and Civilisation in China. Vol. 1. Cambridge University Press. Needham, Joseph (1986a). Mathematics and the Sciences of the Heavens and the Earth. Science and Civilisation in China. Vol. 3. Taipei: Caves Books Ltd. Needham, Joseph (1986c). Physics and Physical Technology, Part 2, Mechanical Engineering. Science and Civilisation in China. Vol. 4. Taipei: Caves Books Ltd. Needham, Joseph; Robinson, Kenneth G.; Huang, Jen-Yü (2004). "General Conclusions and Reflections". Science and Chinese society. Science and Civilisation in China. Vol. 7. Cambridge University Press. Sambursky, Shmuel (1974). Physical Thought from the Presocratics to the Quantum Physicists: an anthology selected, introduced and edited by Shmuel Sambursky. Pica Press. p. 584. ISBN 978-0-87663-712-8. == Further reading == == External links == 'What is the History of Science', British Academy British Society for the History of Science "Scientific Change". Internet Encyclopedia of Philosophy. The CNRS History of Science and Technology Research Center in Paris (France) (in French) Henry Smith Williams, History of Science, Vols 1–4, online text Digital Archives of the National Institute of Standards and Technology (NIST) Digital facsimiles of books from the History of Science Collection Archived 13 January 2020 at the Wayback Machine, Linda Hall Library Digital Collections Division of History of Science and Technology of the International Union of History and Philosophy of Science Giants of Science (website of the Institute of National Remembrance) History of Science Digital Collection: Utah State University – Contains primary sources by such major figures in the history of scientific inquiry as Otto Brunfels, Charles Darwin, Erasmus Darwin, Carolus Linnaeus Antony van Leeuwenhoek, Jan Swammerdam, James Sowerby, Andreas Vesalius, and others. History of Science Society ("HSS") Archived 15 September 2020 at the Wayback Machine Inter-Divisional Teaching Commission (IDTC) of the International Union for the History and Philosophy of Science (IUHPS) Archived 13 January 2020 at the Wayback Machine International Academy of the History of Science International History, Philosophy and Science Teaching Group IsisCB Explore: History of Science Index An open access discovery tool Museo Galileo – Institute and Museum of the History of Science in Florence, Italy National Center for Atmospheric Research (NCAR) Archives The official site of the Nobel Foundation. Features biographies and info on Nobel laureates The Royal Society, trailblazing science from 1650 to date Archived 18 August 2015 at the Wayback Machine The Vega Science Trust Free to view videos of scientists including Feynman, Perutz, Rotblat, Born and many Nobel Laureates. A Century of Science in America: with special reference to the American Journal of Science, 1818-1918
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Natural science or empirical science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and reproducibility of findings are used to try to ensure the validity of scientific advances. Natural science can be divided into two main branches: life science and physical science. Life science is alternatively known as biology. Physical science is subdivided into branches: physics, astronomy, Earth science and chemistry. These branches of natural science may be further divided into more specialized branches (also known as fields). As empirical sciences, natural sciences use tools from the formal sciences, such as mathematics and logic, converting information about nature into measurements that can be explained as clear statements of the "laws of nature". Modern natural science succeeded more classical approaches to natural philosophy. Galileo, Kepler, Descartes, Bacon, and Newton debated the benefits of using approaches which were more mathematical and more experimental in a methodical way. Still, philosophical perspectives, conjectures, and presuppositions, often overlooked, remain necessary in natural science. Systematic data collection, including discovery science, succeeded natural history, which emerged in the 16th century by describing and classifying plants, animals, minerals, and so on. Today, "natural history" suggests observational descriptions aimed at popular audiences. == Criteria == Philosophers of science have suggested several criteria, including Karl Popper's controversial falsifiability criterion, to help them differentiate scientific endeavors from non-scientific ones. Validity, accuracy, and quality control, such as peer review and reproducibility of findings, are amongst the most respected criteria in today's global scientific community. In natural science, impossibility assertions come to be widely accepted as overwhelmingly probable rather than considered proven to the point of being unchallengeable. The basis for this strong acceptance is a combination of extensive evidence of something not occurring, combined with an underlying theory, very successful in making predictions, whose assumptions lead logically to the conclusion that something is impossible. While an impossibility assertion in natural science can never be proved, it could be refuted by the observation of a single counterexample. Such a counterexample would require that the assumptions underlying the theory that implied the impossibility be re-examined. == Branches of natural science == === Biology === This field encompasses a diverse set of disciplines that examine phenomena related to living organisms. The scale of study can range from sub-component biophysics up to complex ecologies. Biology is concerned with the characteristics, classification and behaviors of organisms, as well as how species were formed and their interactions with each other and the environment. The biological fields of botany, zoology, and medicine date back to early periods of civilization, while microbiology was introduced in the 17th century with the invention of the microscope. However, it was not until the 19th century that biology became a unified science. Once scientists discovered commonalities between all living things, it was decided they were best studied as a whole. Some key developments in biology were the discovery of genetics, evolution through natural selection, the germ theory of disease, and the application of the techniques of chemistry and physics at the level of the cell or organic molecule. Modern biology is divided into subdisciplines by the type of organism and by the scale being studied. Molecular biology is the study of the fundamental chemistry of life, while cellular biology is the examination of the cell; the basic building block of all life. At a higher level, anatomy and physiology look at the internal structures, and their functions, of an organism, while ecology looks at how various organisms interrelate. === Earth science === Earth science (also known as geoscience) is an all-embracing term for the sciences related to the planet Earth, including geology, geography, geophysics, geochemistry, climatology, glaciology, hydrology, meteorology, and oceanography. Although mining and precious stones have been human interests throughout the history of civilization, the development of the related sciences of economic geology and mineralogy did not occur until the 18th century. The study of the earth, particularly paleontology, blossomed in the 19th century. The growth of other disciplines, such as geophysics, in the 20th century led to the development of the theory of plate tectonics in the 1960s, which has had a similar effect on the Earth sciences as the theory of evolution had on biology. Earth sciences today are closely linked to petroleum and mineral resources, climate research, and to environmental assessment and remediation. ==== Atmospheric sciences ==== Although sometimes considered in conjunction with the earth sciences, due to the independent development of its concepts, techniques, and practices and also the fact of it having a wide range of sub-disciplines under its wing, atmospheric science is also considered a separate branch of natural science. This field studies the characteristics of different layers of the atmosphere from ground level to the edge of the space. The timescale of the study also varies from day to century. Sometimes, the field also includes the study of climatic patterns on planets other than Earth. ==== Oceanography ==== The serious study of oceans began in the early- to mid-20th century. As a field of natural science, it is relatively young, but stand-alone programs offer specializations in the subject. Though some controversies remain as to the categorization of the field under earth sciences, interdisciplinary sciences, or as a separate field in its own right, most modern workers in the field agree that it has matured to a state that it has its own paradigms and practices. ==== Planetary science ==== Planetary science or planetology, is the scientific study of planets, which include terrestrial planets like the Earth, and other types of planets, such as gas giants and ice giants. Planetary science also concerns other celestial bodies, such as dwarf planets moons, asteroids, and comets. This largely includes the Solar System, but recently has started to expand to exoplanets, particularly terrestrial exoplanets. It explores various objects, spanning from micrometeoroids to gas giants, to establish their composition, movements, genesis, interrelation, and past. Planetary science is an interdisciplinary domain, having originated from astronomy and Earth science, and currently encompassing a multitude of areas, such as planetary geology, cosmochemistry, atmospheric science, physics, oceanography, hydrology, theoretical planetology, glaciology, and exoplanetology. Related fields encompass space physics, which delves into the impact of the Sun on the bodies in the Solar System, and astrobiology. Planetary science comprises interconnected observational and theoretical branches. Observational research entails a combination of space exploration, primarily through robotic spacecraft missions utilizing remote sensing, and comparative experimental work conducted in Earth-based laboratories. The theoretical aspect involves extensive mathematical modelling and computer simulation. Typically, planetary scientists are situated within astronomy and physics or Earth sciences departments in universities or research centers. However, there are also dedicated planetary science institutes worldwide. Generally, individuals pursuing a career in planetary science undergo graduate-level studies in one of the Earth sciences, astronomy, astrophysics, geophysics, or physics. They then focus their research within the discipline of planetary science. Major conferences are held annually, and numerous peer reviewed journals cater to the diverse research interests in planetary science. Some planetary scientists are employed by private research centers and frequently engage in collaborative research initiatives. === Chemistry === Constituting the scientific study of matter at the atomic and molecular scale, chemistry deals primarily with collections of atoms, such as gases, molecules, crystals, and metals. The composition, statistical properties, transformations, and reactions of these materials are studied. Chemistry also involves understanding the properties and interactions of individual atoms and molecules for use in larger-scale applications. Most chemical processes can be studied directly in a laboratory, using a series of (often well-tested) techniques for manipulating materials, as well as an understanding of the underlying processes. Chemistry is often called "the central science" because of its role in connecting the other natural sciences. Early experiments in chemistry had their roots in the system of alchemy, a set of beliefs combining mysticism with physical experiments. The science of chemistry began to develop with the work of Robert Boyle, the discoverer of gases, and Antoine Lavoisier, who developed the theory of the conservation of mass. The discovery of the chemical elements and atomic theory began to systematize this science, and researchers developed a fundamental understanding of states of matter, ions, chemical bonds and chemical reactions. The success of this science led to a complementary chemical industry that now plays a significant role in the world economy. === Physics === Physics embodies the study of the fundamental constituents of the universe, the forces and interactions they exert on one another, and the results produced by these interactions. Physics is generally regarded as foundational because all other natural sciences use and obey the field's principles and laws. Physics relies heavily on mathematics as the logical framework for formulating and quantifying principles. The study of the principles of the universe has a long history and largely derives from direct observation and experimentation. The formulation of theories about the governing laws of the universe has been central to the study of physics from very early on, with philosophy gradually yielding to systematic, quantitative experimental testing and observation as the source of verification. Key historical developments in physics include Isaac Newton's theory of universal gravitation and classical mechanics, an understanding of electricity and its relation to magnetism, Einstein's theories of special and general relativity, the development of thermodynamics, and the quantum mechanical model of atomic and subatomic physics. The field of physics is vast and can include such diverse studies as quantum mechanics and theoretical physics, applied physics and optics. Modern physics is becoming increasingly specialized, where researchers tend to focus on a particular area rather than being "universalists" like Isaac Newton, Albert Einstein, and Lev Landau, who worked in multiple areas. === Astronomy === Astronomy is a natural science that studies celestial objects and phenomena. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Astronomy is the study of everything in the universe beyond Earth's atmosphere, including objects we can see with our naked eyes. It is one of the oldest sciences. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. There are two types of astronomy: observational astronomy and theoretical astronomy. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. In contrast, Theoretical astronomy is oriented towards developing computer or analytical models to describe astronomical objects and phenomena. This discipline is the science of celestial objects and phenomena that originate outside the Earth's atmosphere. It is concerned with the evolution, physics, chemistry, meteorology, geology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy includes examining, studying, and modeling stars, planets, and comets. Most of the information used by astronomers is gathered by remote observation. However, some laboratory reproduction of celestial phenomena has been performed (such as the molecular chemistry of the interstellar medium). There is considerable overlap with physics and in some areas of earth science. There are also interdisciplinary fields such as astrophysics, planetary sciences, and cosmology, along with allied disciplines such as space physics and astrochemistry. While the study of celestial features and phenomena can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the 17th century. A key factor was Galileo's introduction of the telescope to examine the night sky in more detail. The mathematical treatment of astronomy began with Newton's development of celestial mechanics and the laws of gravitation. However, it was triggered by earlier work of astronomers such as Kepler. By the 19th century, astronomy had developed into formal science, with the introduction of instruments such as the spectroscope and photography, along with much-improved telescopes and the creation of professional observatories. == Interdisciplinary studies == The distinctions between the natural science disciplines are not always sharp, and they share many cross-discipline fields. Physics plays a significant role in the other natural sciences, as represented by astrophysics, geophysics, chemical physics and biophysics. Likewise chemistry is represented by such fields as biochemistry, physical chemistry, geochemistry and astrochemistry. A particular example of a scientific discipline that draws upon multiple natural sciences is environmental science. This field studies the interactions of physical, chemical, geological, and biological components of the environment, with particular regard to the effect of human activities and the impact on biodiversity and sustainability. This science also draws upon expertise from other fields, such as economics, law, and social sciences. A comparable discipline is oceanography, as it draws upon a similar breadth of scientific disciplines. Oceanography is sub-categorized into more specialized cross-disciplines, such as physical oceanography and marine biology. As the marine ecosystem is vast and diverse, marine biology is further divided into many subfields, including specializations in particular species. There is also a subset of cross-disciplinary fields with strong currents that run counter to specialization by the nature of the problems they address. Put another way: In some fields of integrative application, specialists in more than one field are a key part of most scientific discourse. Such integrative fields, for example, include nanoscience, astrobiology, and complex system informatics. === Materials science === Materials science is a relatively new, interdisciplinary field that deals with the study of matter and its properties and the discovery and design of new materials. Originally developed through the field of metallurgy, the study of the properties of materials and solids has now expanded into all materials. The field covers the chemistry, physics, and engineering applications of materials, including metals, ceramics, artificial polymers, and many others. The field's core deals with relating the structure of materials with their properties. Materials science is at the forefront of research in science and engineering. It is an essential part of forensic engineering (the investigation of materials, products, structures, or components that fail or do not operate or function as intended, causing personal injury or damage to property) and failure analysis, the latter being the key to understanding, for example, the cause of various aviation accidents. Many of the most pressing scientific problems that are faced today are due to the limitations of the materials that are available, and, as a result, breakthroughs in this field are likely to have a significant impact on the future of technology. The basis of materials science involves studying the structure of materials and relating them to their properties. Understanding this structure-property correlation, material scientists can then go on to study the relative performance of a material in a particular application. The major determinants of the structure of a material and, thus, of its properties are its constituent chemical elements and how it has been processed into its final form. These characteristics, taken together and related through the laws of thermodynamics and kinetics, govern a material's microstructure and thus its properties. == History == Some scholars trace the origins of natural science as far back as pre-literate human societies, where understanding the natural world was necessary for survival. People observed and built up knowledge about the behavior of animals and the usefulness of plants as food and medicine, which was passed down from generation to generation. These primitive understandings gave way to more formalized inquiry around 3500 to 3000 BC in the Mesopotamian and Ancient Egyptian cultures, which produced the first known written evidence of natural philosophy, the precursor of natural science. While the writings show an interest in astronomy, mathematics, and other aspects of the physical world, the ultimate aim of inquiry about nature's workings was, in all cases, religious or mythological, not scientific. A tradition of scientific inquiry also emerged in Ancient China, where Taoist alchemists and philosophers experimented with elixirs to extend life and cure ailments. They focused on the yin and yang, or contrasting elements in nature; the yin was associated with femininity and coldness, while yang was associated with masculinity and warmth. The five phases – fire, earth, metal, wood, and water – described a cycle of transformations in nature. The water turned into wood, which turned into the fire when it burned. The ashes left by fire were earth. Using these principles, Chinese philosophers and doctors explored human anatomy, characterizing organs as predominantly yin or yang, and understood the relationship between the pulse, the heart, and the flow of blood in the body centuries before it became accepted in the West. Little evidence survives of how Ancient Indian cultures around the Indus River understood nature, but some of their perspectives may be reflected in the Vedas, a set of sacred Hindu texts. They reveal a conception of the universe as ever-expanding and constantly being recycled and reformed. Surgeons in the Ayurvedic tradition saw health and illness as a combination of three humors: wind, bile and phlegm. A healthy life resulted from a balance among these humors. In Ayurvedic thought, the body consisted of five elements: earth, water, fire, wind, and space. Ayurvedic surgeons performed complex surgeries and developed a detailed understanding of human anatomy. Pre-Socratic philosophers in Ancient Greek culture brought natural philosophy a step closer to direct inquiry about cause and effect in nature between 600 and 400 BC. However, an element of magic and mythology remained. Natural phenomena such as earthquakes and eclipses were explained increasingly in the context of nature itself instead of being attributed to angry gods. Thales of Miletus, an early philosopher who lived from 625 to 546 BC, explained earthquakes by theorizing that the world floated on water and that water was the fundamental element in nature. In the 5th century BC, Leucippus was an early exponent of atomism, the idea that the world is made up of fundamental indivisible particles. Pythagoras applied Greek innovations in mathematics to astronomy and suggested that the earth was spherical. === Aristotelian natural philosophy (400 BC–1100 AD) === Later Socratic and Platonic thought focused on ethics, morals, and art and did not attempt an investigation of the physical world; Plato criticized pre-Socratic thinkers as materialists and anti-religionists. Aristotle, however, a student of Plato who lived from 384 to 322 BC, paid closer attention to the natural world in his philosophy. In his History of Animals, he described the inner workings of 110 species, including the stingray, catfish and bee. He investigated chick embryos by breaking open eggs and observing them at various stages of development. Aristotle's works were influential through the 16th century, and he is considered to be the father of biology for his pioneering work in that science. He also presented philosophies about physics, nature, and astronomy using inductive reasoning in his works Physics and Meteorology. While Aristotle considered natural philosophy more seriously than his predecessors, he approached it as a theoretical branch of science. Still, inspired by his work, Ancient Roman philosophers of the early 1st century AD, including Lucretius, Seneca and Pliny the Elder, wrote treatises that dealt with the rules of the natural world in varying degrees of depth. Many Ancient Roman Neoplatonists of the 3rd to the 6th centuries also adapted Aristotle's teachings on the physical world to a philosophy that emphasized spiritualism. Early medieval philosophers including Macrobius, Calcidius and Martianus Capella also examined the physical world, largely from a cosmological and cosmographical perspective, putting forth theories on the arrangement of celestial bodies and the heavens, which were posited as being composed of aether. Aristotle's works on natural philosophy continued to be translated and studied amid the rise of the Byzantine Empire and Abbasid Caliphate. In the Byzantine Empire, John Philoponus, an Alexandrian Aristotelian commentator and Christian theologian, was the first to question Aristotle's physics teaching. Unlike Aristotle, who based his physics on verbal argument, Philoponus instead relied on observation and argued for observation rather than resorting to a verbal argument. He introduced the theory of impetus. John Philoponus' criticism of Aristotelian principles of physics served as inspiration for Galileo Galilei during the Scientific Revolution. A revival in mathematics and science took place during the time of the Abbasid Caliphate from the 9th century onward, when Muslim scholars expanded upon Greek and Indian natural philosophy. The words alcohol, algebra and zenith all have Arabic roots. === Medieval natural philosophy (1100–1600) === Aristotle's works and other Greek natural philosophy did not reach the West until about the middle of the 12th century, when works were translated from Greek and Arabic into Latin. The development of European civilization later in the Middle Ages brought with it further advances in natural philosophy. European inventions such as the horseshoe, horse collar and crop rotation allowed for rapid population growth, eventually giving way to urbanization and the foundation of schools connected to monasteries and cathedrals in modern-day France and England. Aided by the schools, an approach to Christian theology developed that sought to answer questions about nature and other subjects using logic. This approach, however, was seen by some detractors as heresy. By the 12th century, Western European scholars and philosophers came into contact with a body of knowledge of which they had previously been ignorant: a large corpus of works in Greek and Arabic that were preserved by Islamic scholars. Through translation into Latin, Western Europe was introduced to Aristotle and his natural philosophy. These works were taught at new universities in Paris and Oxford by the early 13th century, although the practice was frowned upon by the Catholic church. A 1210 decree from the Synod of Paris ordered that "no lectures are to be held in Paris either publicly or privately using Aristotle's books on natural philosophy or the commentaries, and we forbid all this under pain of ex-communication." In the late Middle Ages, Spanish philosopher Dominicus Gundissalinus translated a treatise by the earlier Persian scholar Al-Farabi called On the Sciences into Latin, calling the study of the mechanics of nature Scientia naturalis, or natural science. Gundissalinus also proposed his classification of the natural sciences in his 1150 work On the Division of Philosophy. This was the first detailed classification of the sciences based on Greek and Arab philosophy to reach Western Europe. Gundissalinus defined natural science as "the science considering only things unabstracted and with motion," as opposed to mathematics and sciences that rely on mathematics. Following Al-Farabi, he separated the sciences into eight parts, including: physics, cosmology, meteorology, minerals science, and plant and animal science. Later, philosophers made their own classifications of the natural sciences. Robert Kilwardby wrote On the Order of the Sciences in the 13th century that classed medicine as a mechanical science, along with agriculture, hunting, and theater, while defining natural science as the science that deals with bodies in motion. Roger Bacon, an English friar and philosopher, wrote that natural science dealt with "a principle of motion and rest, as in the parts of the elements of fire, air, earth, and water, and in all inanimate things made from them." These sciences also covered plants, animals and celestial bodies. Later in the 13th century, a Catholic priest and theologian Thomas Aquinas defined natural science as dealing with "mobile beings" and "things which depend on a matter not only for their existence but also for their definition." There was broad agreement among scholars in medieval times that natural science was about bodies in motion. However, there was division about including fields such as medicine, music, and perspective. Philosophers pondered questions including the existence of a vacuum, whether motion could produce heat, the colors of rainbows, the motion of the earth, whether elemental chemicals exist, and where in the atmosphere rain is formed. In the centuries up through the end of the Middle Ages, natural science was often mingled with philosophies about magic and the occult. Natural philosophy appeared in various forms, from treatises to encyclopedias to commentaries on Aristotle. The interaction between natural philosophy and Christianity was complex during this period; some early theologians, including Tatian and Eusebius, considered natural philosophy an outcropping of pagan Greek science and were suspicious of it. Although some later Christian philosophers, including Aquinas, came to see natural science as a means of interpreting scripture, this suspicion persisted until the 12th and 13th centuries. The Condemnation of 1277, which forbade setting philosophy on a level equal with theology and the debate of religious constructs in a scientific context, showed the persistence with which Catholic leaders resisted the development of natural philosophy even from a theological perspective. Aquinas and Albertus Magnus, another Catholic theologian of the era, sought to distance theology from science in their works. "I don't see what one's interpretation of Aristotle has to do with the teaching of the faith," he wrote in 1271. === Newton and the scientific revolution (1600–1800) === By the 16th and 17th centuries, natural philosophy evolved beyond commentary on Aristotle as more early Greek philosophy was uncovered and translated. The invention of the printing press in the 15th century, the invention of the microscope and telescope, and the Protestant Reformation fundamentally altered the social context in which scientific inquiry evolved in the West. Christopher Columbus's discovery of a new world changed perceptions about the physical makeup of the world, while observations by Copernicus, Tyco Brahe and Galileo brought a more accurate picture of the solar system as heliocentric and proved many of Aristotle's theories about the heavenly bodies false. Several 17th-century philosophers, including René Descartes, Pierre Gassendi, Marin Mersenne, Nicolas Malebranche, Thomas Hobbes, John Locke and Francis Bacon, made a break from the past by rejecting Aristotle and his medieval followers outright, calling their approach to natural philosophy superficial. The titles of Galileo's work Two New Sciences and Johannes Kepler's New Astronomy underscored the atmosphere of change that took hold in the 17th century as Aristotle was dismissed in favor of novel methods of inquiry into the natural world. Bacon was instrumental in popularizing this change; he argued that people should use the arts and sciences to gain dominion over nature. To achieve this, he wrote that "human life [must] be endowed with discoveries and powers." He defined natural philosophy as "the knowledge of Causes and secret motions of things; and enlarging the bounds of Human Empire, to the effecting of all things possible." Bacon proposed that scientific inquiry be supported by the state and fed by the collaborative research of scientists, a vision that was unprecedented in its scope, ambition, and forms at the time. Natural philosophers came to view nature increasingly as a mechanism that could be taken apart and understood, much like a complex clock. Natural philosophers including Isaac Newton, Evangelista Torricelli and Francesco Redi, Edme Mariotte, Jean-Baptiste Denis and Jacques Rohault conducted experiments focusing on the flow of water, measuring atmospheric pressure using a barometer and disproving spontaneous generation. Scientific societies and scientific journals emerged and were spread widely through the printing press, touching off the scientific revolution. Newton in 1687 published his The Mathematical Principles of Natural Philosophy, or Principia Mathematica, which set the groundwork for physical laws that remained current until the 19th century. Some modern scholars, including Andrew Cunningham, Perry Williams, and Floris Cohen, argue that natural philosophy is not properly called science and that genuine scientific inquiry began only with the scientific revolution. According to Cohen, "the emancipation of science from an overarching entity called 'natural philosophy is one defining characteristic of the Scientific Revolution." Other historians of science, including Edward Grant, contend that the scientific revolution that blossomed in the 17th, 18th, and 19th centuries occurred when principles learned in the exact sciences of optics, mechanics, and astronomy began to be applied to questions raised by natural philosophy. Grant argues that Newton attempted to expose the mathematical basis of nature – the immutable rules it obeyed – and, in doing so, joined natural philosophy and mathematics for the first time, producing an early work of modern physics. The scientific revolution, which began to take hold in the 17th century, represented a sharp break from Aristotelian modes of inquiry. One of its principal advances was the use of the scientific method to investigate nature. Data was collected, and repeatable measurements were made in experiments. Scientists then formed hypotheses to explain the results of these experiments. The hypothesis was then tested using the principle of falsifiability to prove or disprove its accuracy. The natural sciences continued to be called natural philosophy, but the adoption of the scientific method took science beyond the realm of philosophical conjecture and introduced a more structured way of examining nature. Newton, an English mathematician and physicist, was a seminal figure in the scientific revolution. Drawing on advances made in astronomy by Copernicus, Brahe, and Kepler, Newton derived the universal law of gravitation and laws of motion. These laws applied both on earth and in outer space, uniting two spheres of the physical world previously thought to function independently, according to separate physical rules. Newton, for example, showed that the tides were caused by the gravitational pull of the moon. Another of Newton's advances was to make mathematics a powerful explanatory tool for natural phenomena. While natural philosophers had long used mathematics as a means of measurement and analysis, its principles were not used as a means of understanding cause and effect in nature until Newton. In the 18th century and 19th century, scientists including Charles-Augustin de Coulomb, Alessandro Volta, and Michael Faraday built upon Newtonian mechanics by exploring electromagnetism, or the interplay of forces with positive and negative charges on electrically charged particles. Faraday proposed that forces in nature operated in "fields" that filled space. The idea of fields contrasted with the Newtonian construct of gravitation as simply "action at a distance", or the attraction of objects with nothing in the space between them to intervene. James Clerk Maxwell in the 19th century unified these discoveries in a coherent theory of electrodynamics. Using mathematical equations and experimentation, Maxwell discovered that space was filled with charged particles that could act upon each other and were a medium for transmitting charged waves. Significant advances in chemistry also took place during the scientific revolution. Antoine Lavoisier, a French chemist, refuted the phlogiston theory, which posited that things burned by releasing "phlogiston" into the air. Joseph Priestley had discovered oxygen in the 18th century, but Lavoisier discovered that combustion was the result of oxidation. He also constructed a table of 33 elements and invented modern chemical nomenclature. Formal biological science remained in its infancy in the 18th century, when the focus lay upon the classification and categorization of natural life. This growth in natural history was led by Carl Linnaeus, whose 1735 taxonomy of the natural world is still in use. Linnaeus, in the 1750s, introduced scientific names for all his species. === 19th-century developments (1800–1900) === By the 19th century, the study of science had come into the purview of professionals and institutions. In so doing, it gradually acquired the more modern name of natural science. The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences. But the word did not enter general use until nearly the end of the same century. === Modern natural science (1900–present) === According to a famous 1923 textbook, Thermodynamics and the Free Energy of Chemical Substances, by the American chemist Gilbert N. Lewis and the American physical chemist Merle Randall, the natural sciences contain three great branches: Aside from the logical and mathematical sciences, there are three great branches of natural science which stand apart by reason of the variety of far reaching deductions drawn from a small number of primary postulates — they are mechanics, electrodynamics, and thermodynamics. Today, natural sciences are more commonly divided into life sciences, such as botany and zoology, and physical sciences, which include physics, chemistry, astronomy, and Earth sciences. == See also == Branches of science Empiricism List of academic disciplines and sub-disciplines Logology (science) Natural history Natural Sciences (Cambridge), for the Tripos at the University of Cambridge == References == === Bibliography === == Further reading == Defining Natural Sciences Ledoux, S. F., 2002: Defining Natural Sciences, Behaviorology Today, 5(1), 34–36. Stokes, Donald E. (1997). Pasteur's Quadrant: Basic Science and Technological Innovation. Revised and translated by Albert V. Carozzi and Marguerite Carozzi. Washington, D.C.: Brookings Institution Press. ISBN 978-0-8157-8177-6. The History of Recent Science and Technology Natural Sciences Contains updated information on research in the Natural Sciences including biology, geography and the applied life and earth sciences. Reviews of Books About Natural Science This site contains over 50 previously published reviews of books about natural science, plus selected essays on timely topics in natural science. Scientific Grant Awards Database Contains details of over 2,000,000 scientific research projects conducted over the past 25 years. E!Science Up-to-date science news aggregator from major sources including universities.
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A Bachelor of Applied Science (BAS or BASc) is an undergraduate academic degree of applied sciences. == Usage == In Canada, the Netherlands and other places the Bachelor of Applied Science (BASc) is equivalent to the Bachelor of Engineering, and is classified as a professional degree. In Australia and New Zealand this degree is awarded in various fields of study and is considered a highly specialized professional degree. In the United States, it is also considered a highly specialized professional technical degree; the Bachelor of Applied Science (BAS) is an applied baccalaureate, typically containing advanced technical education in sciences combined with liberal arts education that traditional degrees do not have. Yet, an earned BAS degree includes the same amount of required coursework as traditional bachelor's degree programs. Compared to the Bachelor of Arts (BA) and Bachelor of Science (BS), a BAS degree combines “theoretical and hands-on knowledge and skills that build on a variety of educational backgrounds”. BAS degrees often enhance occupational/technical education. In February 2009, the Dutch Minister of Education, Culture and Science, Ronald Plasterk, proposed to replace all the existing degrees offered by Dutch vocational universities, such as the BBA, BEd and BEng, with the BAA and the BASc. Similarly, the United States has taken BAS as an official degree name. == Fields of study == The BAS usually requires a student to take a majority of their courses in the applied sciences, specializing in a specific area such as the following: Agricultural systems Applied physics Applied mathematics Architectural engineering General engineering Automotive engineering Building Arts Biological engineering Biochemical engineering Built Environment Business informatics Chemical engineering Civil engineering Computer science Computer engineering Communication Construction Management Criminal justice Criminology Electrical engineering Environmental engineering Geomatics Occupational health and safety Public health Engineering management Engineering physics Engineering science Engineering science and mechanics Geological engineering Hospitality Management Industrial engineering Information management Integrated engineering Information systems Information technology Management engineering Management of technology Manufacturing engineering Manufacturing Management Materials science & engineering Mechanical engineering Mechanical engineering technology Mechatronics engineering Mining engineering Microbiology Nanotechnology engineering Nutrition and Food Paralegal Studies Forensics Astrophysics Professional Technical Teacher Education Project Management Property and Valuation Software engineering Sound engineering Surveying Sustainable building science technology Systems engineering Regional and Urban Planning Applied physics & electronic engineering Business management Social science Leadership == See also == Bachelor of Applied Arts Bachelor of Applied Arts and Sciences Bachelor of Arts Bachelor of Science Bachelor of Science in Information Technology Bachelor's degree == References ==
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https://en.wikipedia.org/wiki/Bachelor_of_Applied_Science
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Science of Team Science (SciTS) is a field of scientific philosophy and methodology focused on understanding and improving cross-disciplinary collaboration in research. The field encompasses conceptual and methodological strategies to understand how scientific teams can be organized to work more effectively. SciTS initiatives are concerned with understanding and managing factors that facilitate or hinder the effectiveness of collaborative science, as well as evaluating its outcomes. == History == Since the 1990s, interest in and funding for large-scale, team-based research initiatives has increased, driven by efforts to address complex problems through cross-disciplinary collaboration. Some argue that this trend reflects the growing recognition that addressing multifaceted challenges—such as climate change and public health issues—benefits from partnerships among scientists and practitioners from diverse fields. A systematic review of SciTS literature noted that it is an "essential dimension of interprofessional collaborative research practice" and advocated for incorporating SciTS into an expanded understanding of the intersection of health professions education and clinical practice within the National Center for Interprofessional Practice and Education (NCIPE) at the University of Minnesota. (NCIPE) at the University of Minnesota The interdisciplinary nature of SciTS initially emerged from practical concerns raised by funding agencies, which sought to assess the performance of team science, understand its added value, evaluate the return on investment in large research initiatives, and inform scientific policy. The term "science of team science" was first introduced in October 2006 at a conference called The Science of Team Science: Assessing the Value of Transdisciplinary Research, hosted by the National Cancer Institute in Bethesda, Maryland. The SciTS field was further developed in a supplement to the American Journal of Preventive Medicine, published in July 2008. Two years later, the First Annual International Science of Team Science (SciTS) Conference was held on April 22–24, 2010, in Chicago, Illinois, organized by the Northwestern University Clinical and Translational Sciences (NUCATS) Institute. In 2013, the National Academy of Sciences established a National Research Council Committee on the Science of Team Science to evaluate the current state of knowledge and practice in SciTS. A committee report was later published in 2015. In 2023, Patrick Forscher and colleagues published a review identifying the benefits of big team science, noting that innovations facilitate the collection of larger samples and support efforts toward reproducibility and generalizability. However, concerns exist that team science could increasingly influence funding priorities, potentially shifting emphasis from applied to more theoretical research areas, as well as leading to unsuccessful large-scale projects. Forscher's recommendations included creating an advisory board and structured bylaws, formalizing feedback mechanisms from contributors, engaging in mentoring, and separating idea generation from project implementation. == Methods == The definition of a successful team may differ depending on the stakeholder. SciTS uses both qualitative and quantitative methods to evaluate the antecedent conditions, collaborative processes, and outcomes associated with team science, as well as the organizational, social, and political context that influences team science. A 2018 review of literature on SciTS published between 2006 and 2016 identified 109 articles. It reported that 75% of these articles used pre-existing data (e.g., archival data), 62% used bibliometrics, over 40% used surveys, and over 10% used interview and observational data. == See also == Integrative learning Interactional expertise Interdisciplinarity Multidisciplinarity Multidimensional network Transdisciplinarity Global brain == References == == Further reading == Azoulay P, Joshua S, Zivin JW (2010). "Superstar Extinction". The Quarterly Journal of Economics. 125 (2): 549–589. Bennett LM, Gadlin H, Levine-Finley S (2010). "Collaboration and team science: a field guide" (PDF). Bethesda, Maryland: National Institutes of Health. Accessed May 28, 2010. Börner, Katy; Dall'Asta, Luca; Ke, Weimao; Vespignani, Alessandro (2005). "Studying the emerging global brain: Analyzing and visualizing the impact of co-authorship teams" (PDF). Complexity. 10 (4): 57–67. arXiv:cond-mat/0502147. Bibcode:2005Cmplx..10d..57B. doi:10.1002/cplx.20078. ISSN 1076-2787. S2CID 2190589. Contractor, Noshir (2009). "The Emergence of Multidimensional Networks". Journal of Computer-Mediated Communication. 14 (3): 743–747. doi:10.1111/j.1083-6101.2009.01465.x. ISSN 1083-6101. Cummings JN. "A socio-technical framework for identifying team science collaborations that could benefit from cyberinfrastructure". VOSS: National Science Foundation; 2009. Stokols D, Taylor B, Hall K, Moser R (2006). "The science of team science: an overview of the field" (PDF). Bethesda, Maryland: National Cancer Institute. Accessed May 28, 2010. Rhoten D (2007). The dawn of networked science. The Chronicle Review. 54. Accessed May 28, 2010. == External links == Annual International Science of Team Science Conference National Cancer Institute Science of Team Science website
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https://en.wikipedia.org/wiki/Science_of_team_science
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Materials science in science fiction is the study of how materials science is portrayed in works of science fiction. The accuracy of the materials science portrayed spans a wide range – sometimes it is an extrapolation of existing technology, sometimes it is a physically realistic portrayal of a far-out technology, and sometimes it is simply a plot device that looks scientific, but has no basis in science. Examples are: Realistic: In 1944, the science fiction story "Deadline" by Cleve Cartmill depicted the atomic bomb. The properties of various radioactive isotopes are critical to the proposed device, and the plot. This technology was real, unknown to the author. Extrapolation: In the 1979 novel The Fountains of Paradise, Arthur C. Clarke wrote about space elevators – basically long cables extending from the Earth's surface to geosynchronous orbit. These require a material with enormous tensile strength and light weight. Carbon nanotubes are strong enough in theory, so the idea is plausible; while one cannot be built today, it violates no physical principles. Plot device: An example of an unsupported plot device is scrith, the material used to construct Ringworld, in the novels by Larry Niven. Scrith has unreasonable strength, and is unsupported by known physics, but needed for the plot. Critical analysis of materials science in science fiction falls into the same general categories. The predictive aspects are emphasized, for example, in the motto of the Georgia Tech's department of materials science and engineering – Materials scientists lead the way in turning yesterday's science fiction into tomorrow's reality. This is also the theme of many technical articles, such as Material By Design: Future Science or Science Fiction?, found in IEEE Spectrum, the flagship magazine of the Institute of Electrical and Electronics Engineers. On the other hand, there is criticism of the unrealistic materials science used in science fiction. In the professional materials science journal JOM, for example, there are articles such as The (Mostly Improbable) Materials Science and Engineering of the Star Wars Universe and Personification: The Materials Science and Engineering of Humanoid Robots. == Examples == In many cases, the materials science aspect of a fictional work was interesting enough that someone other than the author has remarked on it. Here are some examples, and their relationship to real world materials science usage, if any. == See also == Science in science fiction Hypothetical types of biochemistry. Most of these potential types of biochemistry have been used in science fiction. Unobtainium List of fictional elements, materials, isotopes and atomic particles Category:Fictional materials Category:Fiction about physics == References == The Science in Science Fiction by Brian Stableford, David Langford, & Peter Nicholls (1982)
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https://en.wikipedia.org/wiki/Materials_science_in_science_fiction
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A medical science liaison (MSL) is a healthcare consulting professional who is employed by pharmaceutical, biotechnology, medical device, and managed care companies. Other job titles for medical science liaisons may include medical liaisons, clinical science liaisons, medical science managers, regional medical scientists, and regional medical directors. The term "MSL" was originally trademarked by Upjohn as "Education services – namely, initiation of drug studies in laboratory and clinical settings and development of workshops, symposia, and seminars for physicians, medical societies, specialty organizations, academicians, in concert, concerned with drug related medical topics" in 1967 and with first use in commerce in 1967. As the number of MSL programs in healthcare increased, subsequent peer-reviewed journal publications and books became available to examine the emerging role of medical affairs and the use of MSLs in an increasingly vertically integrated biotechnology industry. == Role == MSLs build relationships with key opinion leaders or thought leaders and health care providers, providing critical windows of insight into the market and competition. Through such monitoring, MSLs can gain access to key influencers by interacting with national and regional societies and organizations. Moreover, as MSLs specialize in a particular therapeutic area and have scientific knowledge related to it. The educational background of MSLs consists primarily of MDs, DMSc, PharmD, and PhD professionals. Other professions who work as MSLs include Physician Assistants and Nurses. According to the program's advocates, the Board Certified Medical Affairs Specialist (BCMAS) program is the recognized MSL board certification for MSL professionals. They are now highly involved in activities related to clinical trials. == Responsibilities == The medical science liaison role is varied and day-to-day activities include (but are not limited to); Managing investigator initiated studies Performing KOL stakeholder mapping Developing collaborative relationships with KOLs Organising advisory boards Maintaining a high level of therapeutic area knowledge Training sales representatives Providing medical review to ensure all company materials are compliant and accurately reflect the body of scientific evidence Delivering insights from KOLs to inform the medical affairs strategy == See also == Biopharmaceutical – Drug made from biological source Pharmaceutical manufacturing – Synthesis of pharmaceutical drugs Pharmaceutical marketing – Advertising by pharmaceutical companies == References ==
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https://en.wikipedia.org/wiki/Medical_science_liaison
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Environmental science is an interdisciplinary academic field that integrates physics, biology, meteorology, mathematics and geography (including ecology, chemistry, plant science, zoology, mineralogy, oceanography, limnology, soil science, geology and physical geography, and atmospheric science) to the study of the environment, and the solution of environmental problems. Environmental science emerged from the fields of natural history and medicine during the Enlightenment. Today it provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems. Environmental scientists seek to understand the earth's physical, chemical, biological, and geological processes, and to use that knowledge to understand how issues such as alternative energy systems, pollution control and mitigation, natural resource management, and the effects of global warming and climate change influence and affect the natural systems and processes of earth. Environmental issues almost always include an interaction of physical, chemical, and biological processes. Environmental scientists bring a systems approach to the analysis of environmental problems. Key elements of an effective environmental scientist include the ability to relate space, and time relationships as well as quantitative analysis. Environmental science came alive as a substantive, active field of scientific investigation in the 1960s and 1970s driven by (a) the need for a multi-disciplinary approach to analyze complex environmental problems, (b) the arrival of substantive environmental laws requiring specific environmental protocols of investigation and (c) the growing public awareness of a need for action in addressing environmental problems. Events that spurred this development included the publication of Rachel Carson's landmark environmental book Silent Spring along with major environmental issues becoming very public, such as the 1969 Santa Barbara oil spill, and the Cuyahoga River of Cleveland, Ohio, "catching fire" (also in 1969), and helped increase the visibility of environmental issues and create this new field of study. == Terminology == In common usage, "environmental science" and "ecology" are often used interchangeably, but technically, ecology refers only to the study of organisms and their interactions with each other as well as how they interrelate with environment. Ecology could be considered a subset of environmental science, which also could involve purely chemical or public health issues (for example) ecologists would be unlikely to study. In practice, there are considerable similarities between the work of ecologists and other environmental scientists. There is substantial overlap between ecology and environmental science with the disciplines of fisheries, forestry, and wildlife. Environmental studies incorporates more of the social sciences for understanding human relationships, perceptions and policies towards the environment. Environmental engineering focuses on design and technology for improving environmental quality in every aspect. == History == === Ancient civilizations === Historical concern for environmental issues is well documented in archives around the world. Ancient civilizations were mainly concerned with what is now known as environmental science insofar as it related to agriculture and natural resources. Scholars believe that early interest in the environment began around 6000 BCE when ancient civilizations in Israel and Jordan collapsed due to deforestation. As a result, in 2700 BCE the first legislation limiting deforestation was established in Mesopotamia. Two hundred years later, in 2500 BCE, a community residing in the Indus River Valley observed the nearby river system in order to improve sanitation. This involved manipulating the flow of water to account for public health. In the Western Hemisphere, numerous ancient Central American city-states collapsed around 1500 BCE due to soil erosion from intensive agriculture. Those remaining from these civilizations took greater attention to the impact of farming practices on the sustainability of the land and its stable food production. Furthermore, in 1450 BCE the Minoan civilization on the Greek island of Crete declined due to deforestation and the resulting environmental degradation of natural resources. Pliny the Elder somewhat addressed the environmental concerns of ancient civilizations in the text Naturalis Historia, written between 77 and 79 ACE, which provided an overview of many related subsets of the discipline. Although warfare and disease were of primary concern in ancient society, environmental issues played a crucial role in the survival and power of different civilizations. As more communities recognized the importance of the natural world to their long-term success, an interest in studying the environment came into existence. === Beginnings of environmental science === ==== 18th century ==== In 1735, the concept of binomial nomenclature is introduced by Carolus Linnaeus as a way to classify all living organisms, influenced by earlier works of Aristotle. His text, Systema Naturae, represents one of the earliest culminations of knowledge on the subject, providing a means to identify different species based partially on how they interact with their environment. ==== 19th century ==== In the 1820s, scientists were studying the properties of gases, particularly those in the Earth's atmosphere and their interactions with heat from the Sun. Later that century, studies suggested that the Earth had experienced an Ice Age and that warming of the Earth was partially due to what are now known as greenhouse gases (GHG). The greenhouse effect was introduced, although climate science was not yet recognized as an important topic in environmental science due to minimal industrialization and lower rates of greenhouse gas emissions at the time. ==== 20th century ==== In the 1900s, the discipline of environmental science as it is known today began to take shape. The century is marked by significant research, literature, and international cooperation in the field. In the early 20th century, criticism from dissenters downplayed the effects of global warming. At this time, few researchers were studying the dangers of fossil fuels. After a 1.3 degrees Celsius temperature anomaly was found in the Atlantic Ocean in the 1940s, however, scientists renewed their studies of gaseous heat trapping from the greenhouse effect (although only carbon dioxide and water vapor were known to be greenhouse gases then). Nuclear development following the Second World War allowed environmental scientists to intensively study the effects of carbon and make advancements in the field. Further knowledge from archaeological evidence brought to light the changes in climate over time, particularly ice core sampling. Environmental science was brought to the forefront of society in 1962 when Rachel Carson published an influential piece of environmental literature, Silent Spring. Carson's writing led the American public to pursue environmental safeguards, such as bans on harmful chemicals like the insecticide DDT. Another important work, The Tragedy of the Commons, was published by Garrett Hardin in 1968 in response to accelerating natural degradation. In 1969, environmental science once again became a household term after two striking disasters: Ohio's Cuyahoga River caught fire due to the amount of pollution in its waters and a Santa Barbara oil spill endangered thousands of marine animals, both receiving prolific media coverage. Consequently, the United States passed an abundance of legislation, including the Clean Water Act and the Great Lakes Water Quality Agreement. The following year, in 1970, the first ever Earth Day was celebrated worldwide and the United States Environmental Protection Agency (EPA) was formed, legitimizing the study of environmental science in government policy. In the next two years, the United Nations created the United Nations Environment Programme (UNEP) in Stockholm, Sweden to address global environmental degradation. Much of the interest in environmental science throughout the 1970s and the 1980s was characterized by major disasters and social movements. In 1978, hundreds of people were relocated from Love Canal, New York after carcinogenic pollutants were found to be buried underground near residential areas. The next year, in 1979, the nuclear power plant on Three Mile Island in Pennsylvania suffered a meltdown and raised concerns about the dangers of radioactive waste and the safety of nuclear energy. In response to landfills and toxic waste often disposed of near their homes, the official Environmental Justice Movement was started by a Black community in North Carolina in 1982. Two years later, the toxic methyl isocyanate gas was released to the public from a power plant disaster in Bhopal, India, harming hundreds of thousands of people living near the disaster site, the effects of which are still felt today. In a groundbreaking discovery in 1985, a British team of researchers studying Antarctica found evidence of a hole in the ozone layer, inspiring global agreements banning the use of chlorofluorocarbons (CFCs), which were previously used in nearly all aerosols and refrigerants. Notably, in 1986, the meltdown at the Chernobyl nuclear power plant in Ukraine released radioactive waste to the public, leading to international studies on the ramifications of environmental disasters. Over the next couple of years, the Brundtland Commission (previously known as the World Commission on Environment and Development) published a report titled Our Common Future and the Montreal Protocol formed the International Panel on Climate Change (IPCC) as international communication focused on finding solutions for climate change and degradation. In the late 1980s, the Exxon Valdez company was fined for spilling large quantities of crude oil off the coast of Alaska and the resulting cleanup, involving the work of environmental scientists. After hundreds of oil wells were burned in combat in 1991, warfare between Iraq and Kuwait polluted the surrounding atmosphere just below the air quality threshold environmental scientists believed was life-threatening. ==== 21st century ==== Many niche disciplines of environmental science have emerged over the years, although climatology is one of the most known topics. Since the 2000s, environmental scientists have focused on modeling the effects of climate change and encouraging global cooperation to minimize potential damages. In 2002, the Society for the Environment as well as the Institute of Air Quality Management were founded to share knowledge and develop solutions around the world. Later, in 2008, the United Kingdom became the first country to pass legislation (the Climate Change Act) that aims to reduce carbon dioxide output to a specified threshold. In 2016 the Kyoto Protocol became the Paris Agreement, which sets concrete goals to reduce greenhouse gas emissions and restricts Earth's rise in temperature to a 2 degrees Celsius maximum. The agreement is one of the most expansive international efforts to limit the effects of global warming to date. Most environmental disasters in this time period involve crude oil pollution or the effects of rising temperatures. In 2010, BP was responsible for the largest American oil spill in the Gulf of Mexico, known as the Deepwater Horizon spill, which killed a number of the company's workers and released large amounts of crude oil into the water. Furthermore, throughout this century, much of the world has been ravaged by widespread wildfires and water scarcity, prompting regulations on the sustainable use of natural resources as determined by environmental scientists. The 21st century is marked by significant technological advancements. New technology in environmental science has transformed how researchers gather information about various topics in the field. Research in engines, fuel efficiency, and decreasing emissions from vehicles since the times of the Industrial Revolution has reduced the amount of carbon and other pollutants into the atmosphere. Furthermore, investment in researching and developing clean energy (i.e. wind, solar, hydroelectric, and geothermal power) has significantly increased in recent years, indicating the beginnings of the divestment from fossil fuel use. Geographic information systems (GIS) are used to observe sources of air or water pollution through satellites and digital imagery analysis. This technology allows for advanced farming techniques like precision agriculture as well as monitoring water usage in order to set market prices. In the field of water quality, developed strains of natural and manmade bacteria contribute to bioremediation, the treatment of wastewaters for future use. This method is more eco-friendly and cheaper than manual cleanup or treatment of wastewaters. Most notably, the expansion of computer technology has allowed for large data collection, advanced analysis, historical archives, public awareness of environmental issues, and international scientific communication. The ability to crowdsource on the Internet, for example, represents the process of collectivizing knowledge from researchers around the world to create increased opportunity for scientific progress. With crowdsourcing, data is released to the public for personal analyses which can later be shared as new information is found. Another technological development, blockchain technology, monitors and regulates global fisheries. By tracking the path of fish through global markets, environmental scientists can observe whether certain species are being overharvested to the point of extinction. Additionally, remote sensing allows for the detection of features of the environment without physical intervention. The resulting digital imagery is used to create increasingly accurate models of environmental processes, climate change, and much more. Advancements to remote sensing technology are particularly useful in locating the nonpoint sources of pollution and analyzing ecosystem health through image analysis across the electromagnetic spectrum. Lastly, thermal imaging technology is used in wildlife management to catch and discourage poachers and other illegal wildlife traffickers from killing endangered animals, proving useful for conservation efforts. Artificial intelligence has also been used to predict the movement of animal populations and protect the habitats of wildlife. == Components == === Atmospheric sciences === Atmospheric sciences focus on the Earth's atmosphere, with an emphasis upon its interrelation to other systems. Atmospheric sciences can include studies of meteorology, greenhouse gas phenomena, atmospheric dispersion modeling of airborne contaminants, sound propagation phenomena related to noise pollution, and even light pollution. Taking the example of the global warming phenomena, physicists create computer models of atmospheric circulation and infrared radiation transmission, chemists examine the inventory of atmospheric chemicals and their reactions, biologists analyze the plant and animal contributions to carbon dioxide fluxes, and specialists such as meteorologists and oceanographers add additional breadth in understanding the atmospheric dynamics. === Ecology === As defined by the Ecological Society of America, "Ecology is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them." Ecologists might investigate the relationship between a population of organisms and some physical characteristic of their environment, such as concentration of a chemical; or they might investigate the interaction between two populations of different organisms through some symbiotic or competitive relationship. For example, an interdisciplinary analysis of an ecological system which is being impacted by one or more stressors might include several related environmental science fields. In an estuarine setting where a proposed industrial development could impact certain species by water and air pollution, biologists would describe the flora and fauna, chemists would analyze the transport of water pollutants to the marsh, physicists would calculate air pollution emissions and geologists would assist in understanding the marsh soils and bay muds. === Environmental chemistry === Environmental chemistry is the study of chemical alterations in the environment. Principal areas of study include soil contamination and water pollution. The topics of analysis include chemical degradation in the environment, multi-phase transport of chemicals (for example, evaporation of a solvent containing lake to yield solvent as an air pollutant), and chemical effects upon biota. As an example study, consider the case of a leaking solvent tank which has entered the habitat soil of an endangered species of amphibian. As a method to resolve or understand the extent of soil contamination and subsurface transport of solvent, a computer model would be implemented. Chemists would then characterize the molecular bonding of the solvent to the specific soil type, and biologists would study the impacts upon soil arthropods, plants, and ultimately pond-dwelling organisms that are the food of the endangered amphibian. === Geosciences === Geosciences include environmental geology, environmental soil science, volcanic phenomena and evolution of the Earth's crust. In some classification systems this can also include hydrology, including oceanography. As an example study, of soils erosion, calculations would be made of surface runoff by soil scientists. Fluvial geomorphologists would assist in examining sediment transport in overland flow. Physicists would contribute by assessing the changes in light transmission in the receiving waters. Biologists would analyze subsequent impacts to aquatic flora and fauna from increases in water turbidity. == Regulations driving the studies == In the United States the National Environmental Policy Act (NEPA) of 1969 set forth requirements for analysis of federal government actions (such as highway construction projects and land management decisions) in terms of specific environmental criteria. Numerous state laws have echoed these mandates, applying the principles to local-scale actions. The upshot has been an explosion of documentation and study of environmental consequences before the fact of development actions. One can examine the specifics of environmental science by reading examples of Environmental Impact Statements prepared under NEPA such as: Wastewater treatment expansion options discharging into the San Diego/Tijuana Estuary, Expansion of the San Francisco International Airport, Development of the Houston, Metro Transportation system, Expansion of the metropolitan Boston MBTA transit system, and Construction of Interstate 66 through Arlington, Virginia. In England and Wales the Environment Agency (EA), formed in 1996, is a public body for protecting and improving the environment and enforces the regulations listed on the communities and local government site. (formerly the office of the deputy prime minister). The agency was set up under the Environment Act 1995 as an independent body and works closely with UK Government to enforce the regulations. == See also == Environmental engineering science Environmental informatics Environmental monitoring Environmental planning Environmental statistics Glossary of environmental science List of environmental studies topics == References == == External links == Glossary of environmental terms – Global Development Research Center
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https://en.wikipedia.org/wiki/Environmental_science
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Applied physics is the application of physics to solve scientific or engineering problems. It is usually considered a bridge or a connection between physics and engineering. "Applied" is distinguished from "pure" by a subtle combination of factors, such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of scientific principles in practical devices and systems and with the application of physics in other areas of science and high technology. == Examples of research and development areas == Accelerator physics Acoustics Atmospheric physics Biophysics Brain–computer interfacing Chemistry Chemical physics Differentiable programming Artificial intelligence Scientific computing Engineering physics Chemical engineering Electrical engineering Electronics engineering Computer science & engineering Artificial intelligence Machine learning Deep learning Reinforcement learning Power engineering Power electronics Control engineering Materials science and engineering Metamaterials Nanotechnology Semiconductors Thin films Mechanical engineering Aerospace engineering Astrodynamics Electromagnetic propulsion Fluid mechanics Military engineering Lidar Radar Sonar Stealth technology Nuclear engineering Fission reactors Fusion reactors Optical engineering Photonics Cavity optomechanics Lasers Photonic crystals Geophysics Materials physics Medical physics Health physics Radiation dosimetry Medical imaging Magnetic resonance imaging Radiation therapy Microscopy Scanning probe microscopy Atomic force microscopy Scanning tunneling microscopy Scanning electron microscopy Transmission electron microscopy Nuclear physics Fission Fusion Optical physics Nonlinear optics Quantum optics Plasma physics Quantum technology Quantum computing Quantum cryptography Renewable energy Space physics Spectroscopy == See also == Applied science Applied mathematics Engineering Engineering Physics High Technology == References ==
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https://en.wikipedia.org/wiki/Applied_physics
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Flat Earth is an archaic and scientifically disproven conception of the Earth's shape as a plane or disk. Many ancient cultures, notably in the ancient Near East, subscribed to a flat-Earth cosmography. The model has undergone a recent resurgence as a conspiracy theory in the 21st century. The idea of a spherical Earth appeared in ancient Greek philosophy with Pythagoras (6th century BC). However, the early Greek cosmological view of a flat Earth persisted among most pre-Socratics (6th–5th century BC). In the early 4th century BC, Plato wrote about a spherical Earth. By about 330 BC, his former student Aristotle had provided strong empirical evidence for a spherical Earth. Knowledge of the Earth's global shape gradually began to spread beyond the Hellenistic world. By the early period of the Christian Church, the spherical view was widely held, with some notable exceptions. In contrast, ancient Chinese scholars consistently describe the Earth as flat, and this perception remained unchanged until their encounters with Jesuit missionaries in the 17th century. It is a historical myth that medieval Europeans generally thought the Earth was flat. This myth was created in the 17th century by Protestants to argue against Catholic teachings. Traditionalist Muslim scholars have maintained that the Earth is flat, though, since the 9th century, Muslim scholars have tended to believe in a spherical Earth. Despite the scientific facts and obvious effects of Earth's sphericity, pseudoscientific flat-Earth conspiracy theories persist. Since the 2010s, belief in a flat Earth has increased, both as membership of modern flat Earth societies, and as unaffiliated individuals using social media. In a 2018 study reported on by Scientific American, only 82% of 18- to 24-year-old American respondents agreed with the statement "I have always believed the world is round". However, a firm belief in a flat Earth is rare, with less than 2% acceptance in all age groups. == History == === Belief in flat Earth === ==== Near East ==== In early Egyptian and Mesopotamian thought, the world was portrayed as a disk floating in the ocean. A similar model is found in the Homeric account from the 8th century BC in which "Okeanos, the personified body of water surrounding the circular surface of the Earth, is the begetter of all life and possibly of all gods." The Pyramid Texts and Coffin Texts of ancient Egypt show a similar cosmography; Nun (the Ocean) encircled nbwt ("dry lands" or "Islands"). The Israelites also imagined the Earth to be a disc floating on water with an arched firmament above it that separated the Earth from the heavens. The sky was a solid dome with the Sun, Moon, planets, and stars embedded in it. ==== Greece ==== ===== Poets ===== Both Homer and Hesiod described a disc cosmography on the Shield of Achilles. This poetic tradition of an Earth-encircling (gaiaokhos) sea (Oceanus) and a disc also appears in Stasinus of Cyprus, Mimnermus, Aeschylus, and Apollonius Rhodius. Homer's description of the disc cosmography on the shield of Achilles with the encircling ocean is repeated far later in Quintus Smyrnaeus' Posthomerica (4th century AD), which continues the narration of the Trojan War. ===== Philosophers ===== Several pre-Socratic philosophers believed that the world was flat: Thales (c. 550 BC) according to several sources, and Leucippus (c. 440 BC) and Democritus (c. 460–370 BC) according to Aristotle. Thales thought that the Earth floated in water like a log. It has been argued, however, that Thales actually believed in a spherical Earth. Anaximander (c. 550 BC) believed that the Earth was a short cylinder with a flat, circular top that remained stable because it was the same distance from all things. Anaximenes of Miletus believed that "the Earth is flat and rides on air; in the same way the Sun and the Moon and the other heavenly bodies, which are all fiery, ride the air because of their flatness". Xenophanes (c. 500 BC) thought that the Earth was flat, with its upper side touching the air, and the lower side extending without limit. Belief in a flat Earth continued into the 5th century BC. Anaxagoras (c. 450 BC) agreed that the Earth was flat, and his pupil Archelaus believed that the flat Earth was depressed in the middle like a saucer, to allow for the fact that the Sun does not rise and set at the same time for everyone. ===== Historians ===== Hecataeus of Miletus believed that the Earth was flat and surrounded by water. Herodotus in his Histories ridiculed the belief that water encircled the world, yet most classicists agree that he still believed Earth was flat because of his descriptions of literal "ends" or "edges" of the Earth. ==== Northern Europe ==== The ancient Norse and Germanic peoples believed in a flat-Earth cosmography with the Earth surrounded by an ocean, with the axis mundi, a world tree (Yggdrasil), or pillar (Irminsul) in the centre. In the world-encircling ocean sat a snake called Jormungandr. The Norse creation account preserved in Gylfaginning (VIII) states that during the creation of the Earth, an impassable sea was placed around it: And Jafnhárr said: "Of the blood, which ran and welled forth freely out of his wounds, they made the sea, when they had formed and made firm the Earth together, and laid the sea in a ring round. about her; and it may well seem a hard thing to most men to cross over it." The late Norse Konungs skuggsjá, on the other hand, explains Earth's shape as a sphere: If you take a lighted candle and set it in a room, you may expect it to light up the entire interior, unless something should hinder, though the room be quite large. But if you take an apple and hang it close to the flame, so near that it is heated, the apple will darken nearly half the room or even more. However, if you hang the apple near the wall, it will not get hot; the candle will light up the whole house; and the shadow on the wall where the apple hangs will be scarcely half as large as the apple itself. From this you may infer that the Earth-circle is round like a ball and not equally near the sun at every point. But where the curved surface lies nearest the sun's path, there will the greatest heat be; and some of the lands that lie continuously under the unbroken rays cannot be inhabited. ==== East Asia ==== In ancient China, the prevailing belief was that the Earth was flat and square, while the heavens were round, an assumption virtually unquestioned until the introduction of European astronomy in the 17th century. The English sinologist Cullen emphasizes the point that there was no concept of a round Earth in ancient Chinese astronomy: Chinese thought on the form of the Earth remained almost unchanged from early times until the first contacts with modern science through the medium of Jesuit missionaries in the seventeenth century. While the heavens were variously described as being like an umbrella covering the Earth (the Kai Tian theory), or like a sphere surrounding it (the Hun Tian theory), or as being without substance while the heavenly bodies float freely (the Hsüan yeh theory), the Earth was at all times flat, although perhaps bulging up slightly. The model of an egg was often used by Chinese astronomers such as Zhang Heng (78–139 AD) to describe the heavens as spherical: The heavens are like a hen's egg and as round as a crossbow bullet; the Earth is like the yolk of the egg, and lies in the centre. This analogy with a curved egg led some modern historians, notably Joseph Needham, to conjecture that Chinese astronomers were, after all, aware of the Earth's sphericity. The egg reference, however, was rather meant to clarify the relative position of the flat Earth to the heavens: In a passage of Zhang Heng's cosmogony not translated by Needham, Zhang himself says: "Heaven takes its body from the Yang, so it is round and in motion. Earth takes its body from the Yin, so it is flat and quiescent". The point of the egg analogy is simply to stress that the Earth is completely enclosed by Heaven, rather than merely covered from above as the Kai Tian describes. Chinese astronomers, many of them brilliant men by any standards, continued to think in flat-Earth terms until the seventeenth century; this surprising fact might be the starting-point for a re-examination of the apparent facility with which the idea of a spherical Earth found acceptance in fifth-century BC Greece. Further examples cited by Needham supposed to demonstrate dissenting voices from the ancient Chinese consensus actually refer without exception to the Earth being square, not to it being flat. Accordingly, the 13th-century scholar Li Ye, who argued that the movements of the round heaven would be hindered by a square Earth, did not advocate a spherical Earth, but rather that its edge should be rounded off so as to be circular. However, Needham disagrees, affirming that Li Ye believed the Earth to be spherical, similar in shape to the heavens but much smaller. This was preconceived by the 4th-century scholar Yu Xi, who argued for the infinity of outer space surrounding the Earth and that the latter could be either square or round, in accordance to the shape of the heavens. When Chinese geographers of the 17th century, influenced by European cartography and astronomy, showed the Earth as a sphere that could be circumnavigated by sailing around the globe, they did so with formulaic terminology previously used by Zhang Heng to describe the spherical shape of the Sun and Moon (i.e. that they were as round as a crossbow bullet). As noted in the book Huainanzi, in the 2nd century BC, Chinese astronomers effectively inverted Eratosthenes' calculation of the curvature of the Earth to calculate the height of the Sun above the Earth. By assuming the Earth was flat, they arrived at a distance of 100000 li (approximately 200000 km). The Zhoubi Suanjing also discusses how to determine the distance of the Sun by measuring the length of noontime shadows at different latitudes, a method similar to Eratosthenes' measurement of the circumference of the Earth, but the Zhoubi Suanjing assumes that the Earth is flat. === Alternate or mixed theories === ==== Greece: spherical Earth ==== Pythagoras in the 6th century BC and Parmenides in the 5th century BC stated that the Earth is spherical, and this view spread rapidly in the Greek world. Around 330 BC, Aristotle maintained on the basis of physical theory and observational evidence that the Earth was spherical, and reported an estimate of its circumference. The Earth's circumference was first determined around 240 BC by Eratosthenes. By the 2nd century AD, Ptolemy had derived his maps from a globe and developed the system of latitude, longitude, and climes. His Almagest was written in Greek and only translated into Latin in the 11th century from Arabic translations. Lucretius (1st century BC) opposed the concept of a spherical Earth, because he considered that an infinite universe had no center towards which heavy bodies would tend. Thus, he thought the idea of animals walking around topsy-turvy under the Earth was absurd. By the 1st century AD, Pliny the Elder was in a position to say that everyone agreed on the spherical shape of Earth, though disputes continued regarding the nature of the antipodes, and how it is possible to keep the ocean in a curved shape. ==== South Asia ==== The Vedic texts depict the cosmos in many ways. One of the earliest Indian cosmological texts pictures the Earth as one of a stack of flat disks. In the Vedic texts, Dyaus (heaven) and Prithvi (Earth) are compared to wheels on an axle, yielding a flat model. They are also described as bowls or leather bags, yielding a concave model. According to Macdonell: "the conception of the Earth being a disc surrounded by an ocean does not appear in the Samhitas. But it was naturally regarded as circular, being compared with a wheel (10.89) and expressly called circular (parimandala) in the Shatapatha Brahmana." By about the 5th century AD, the siddhanta astronomy texts of South Asia, particularly of Aryabhata, assume a spherical Earth as they develop mathematical methods for quantitative astronomy for calendar and time keeping. The medieval Indian texts called the Puranas describe the Earth as a flat-bottomed, circular disk with concentric oceans and continents. This general scheme is present not only in the Hindu cosmologies, but also in Buddhist and Jain cosmologies of South Asia. However, some Puranas include other models. The fifth canto of the Bhagavata Purana, for example, includes sections that describe the Earth both as flat and spherical. ==== Early Christian Church ==== During the early period of the Christian Church, the spherical view continued to be widely held, with some notable exceptions. Until the mid-fourth century AD, virtually all Christian authors held that the Earth was round. Athenagoras, an eastern Christian writing around the year 175 AD, said that the Earth was spherical. Methodius (c. 290 AD), an eastern Christian writing against "the theory of the Chaldeans and the Egyptians" said: "Let us first lay bare ... the theory of the Chaldeans and the Egyptians. They say that the circumference of the universe is likened to the turnings of a well-rounded globe, the Earth being a central point. They say that since its outline is spherical, ... the Earth should be the center of the universe, around which the heaven is whirling." Arnobius, another eastern Christian writing sometime around 305 AD, described the round Earth: "In the first place, indeed, the world itself is neither right nor left. It has neither upper nor lower regions, nor front nor back. For whatever is round and bounded on every side by the circumference of a solid sphere, has no beginning or end ..." Other advocates of a round Earth included Eusebius, Hilary of Poitiers, Irenaeus, Hippolytus of Rome, Firmicus Maternus, Ambrose, Jerome, Prudentius, Favonius Eulogius, and others. The only exceptions to this consensus up until the mid-fourth century were Theophilus of Antioch and Lactantius, both of whom held anti-Hellenistic views and associated the round-Earth view with pagan cosmology. Lactantius, a western Christian writer and advisor to the first Christian Roman Emperor, Constantine, writing sometime between 304 and 313 AD, ridiculed the notion of antipodes and the philosophers who fancied that "the universe is round like a ball. They also thought that heaven revolves in accordance with the motion of the heavenly bodies. ... For that reason, they constructed brass globes, as though after the figure of the universe." The influential theologian and philosopher Saint Augustine, one of the four Great Church Fathers of the Western Church, similarly objected to the "fable" of antipodes: But as to the fable that there are Antipodes, that is to say, men on the opposite side of the Earth, where the sun rises when it sets to us, men who walk with their feet opposite ours that is on no ground credible. And, indeed, it is not affirmed that this has been learned by historical knowledge, but by scientific conjecture, on the ground that the Earth is suspended within the concavity of the sky, and that it has as much room on the one side of it as on the other: hence they say that the part that is beneath must also be inhabited. But they do not remark that, although it be supposed or scientifically demonstrated that the world is of a round and spherical form, yet it does not follow that the other side of the Earth is bare of water; nor even, though it be bare, does it immediately follow that it is peopled. For Scripture, which proves the truth of its historical statements by the accomplishment of its prophecies, gives no false information; and it is too absurd to say, that some men might have taken ship and traversed the whole wide ocean, and crossed from this side of the world to the other, and that thus even the inhabitants of that distant region are descended from that one first man. Some historians do not view Augustine's scriptural commentaries as endorsing any particular cosmological model, endorsing instead the view that Augustine shared the common view of his contemporaries that the Earth is spherical, in line with his endorsement of science in De Genesi ad litteram. C. P. E. Nothaft, responding to writers like Leo Ferrari who described Augustine as endorsing a flat Earth, says that "...other recent writers on the subject treat Augustine's acceptance of the Earth's spherical shape as a well-established fact". While it always remained a minority view, from the mid-fourth to the seventh centuries AD, the flat-Earth view experienced a revival, around the time when Diodorus of Tarsus founded the exegetical school known as the School of Antioch, which sought to counter what he saw as the pagan cosmology of the Greeks with a return to the traditional cosmology. The writings of Diodorus did not survive, but are reconstructed from later criticism. This revival primarily took place in the East Syriac world (with little influence on the Latin West) where it gained proponents such as Ephrem the Syrian and in the popular hexaemeral homilies of Jacob of Serugh. Chrysostom, one of the four Great Church Fathers of the Eastern Church and Archbishop of Constantinople, explicitly espoused the idea, based on scripture, that the Earth floats miraculously on the water beneath the firmament. Christian Topography (547) by the Alexandrian monk Cosmas Indicopleustes, who had traveled as far as Sri Lanka and the source of the Blue Nile, is now widely considered the most valuable geographical document of the early medieval age, although it received relatively little attention from contemporaries. In it, the author repeatedly expounds the doctrine that the universe consists of only two places, the Earth below the firmament and heaven above it. Carefully drawing on arguments from scripture, he describes the Earth as a rectangle, 400 days' journey long by 200 wide, surrounded by four oceans and enclosed by four massive walls which support the firmament. The spherical Earth theory is contemptuously dismissed as "pagan". Severian, Bishop of Gabala (d. 408), wrote that the Earth is flat and the Sun does not pass under it in the night, but "travels through the northern parts as if hidden by a wall". Basil of Caesarea (329–379) argued that the matter was theologically irrelevant. ==== Europe: Early Middle Ages ==== Early medieval Christian writers felt little urge to assume flatness of the Earth, though they had fuzzy impressions of the writings of Ptolemy and Aristotle, relying more on Pliny. With the end of the Western Roman Empire, Western Europe entered the Middle Ages with great difficulties that affected the continent's intellectual production. Most scientific treatises of classical antiquity (in Greek) were unavailable, leaving only simplified summaries and compilations. In contrast, the Eastern Roman Empire did not fall, and it preserved the learning. Still, many textbooks of the Early Middle Ages supported the sphericity of the Earth in the western part of Europe. Europe's view of the shape of the Earth in Late Antiquity and the Early Middle Ages may be best expressed by the writings of early Christian scholars: Bishop Isidore of Seville (560–636) taught in his widely read encyclopedia, the Etymologies, diverse views such as that the Earth "resembles a wheel" resembling Anaximander in language and the map that he provided. This was widely interpreted as referring to a disc-shaped Earth. An illustration from Isidore's De Natura Rerum shows the five zones of the Earth as adjacent circles. Some have concluded that he thought the Arctic and Antarctic zones were adjacent to each other. He did not admit the possibility of antipodes, which he took to mean people dwelling on the opposite side of the Earth, considering them legendary and noting that there was no evidence for their existence. Isidore's T and O map, which was seen as representing a small part of a spherical Earth, continued to be used by authors through the Middle Ages, e.g. the 9th-century bishop Rabanus Maurus, who compared the habitable part of the northern hemisphere (Aristotle's northern temperate clime) with a wheel. At the same time, Isidore's works also gave the views of sphericity, for example, in chapter 28 of De Natura Rerum, Isidore claims that the Sun orbits the Earth and illuminates the other side when it is night on this side. See French translation of De Natura Rerum. In his other work Etymologies, there are also affirmations that the sphere of the sky has Earth in its center and the sky being equally distant on all sides. Other researchers have argued these points as well. "The work remained unsurpassed until the thirteenth century and was regarded as the summit of all knowledge. It became an essential part of European medieval culture. Soon after the invention of typography it appeared many times in print." However, "The Scholastics – later medieval philosophers, theologians, and scientists – were helped by the Arabic translators and commentaries, but they hardly needed to struggle against a flat-Earth legacy from the early middle ages (500–1050). Early medieval writers often had fuzzy and imprecise impressions of both Ptolemy and Aristotle and relied more on Pliny, but they felt (with one exception), little urge to assume flatness." St Vergilius of Salzburg (c. 700–784), in the middle of the 8th century, discussed or taught some geographical or cosmographical ideas that St Boniface found sufficiently objectionable that he complained about them to Pope Zachary. The only surviving record of the incident is contained in Zachary's reply, dated 748, where he wrote: As for the perverse and sinful doctrine which he (Virgil) against God and his own soul has uttered – if it shall be clearly established that he professes belief in another world and other men existing beneath the Earth, or in (another) sun and moon there, thou art to hold a council, deprive him of his sacerdotal rank, and expel him from the Church. Some authorities have suggested that the sphericity of the Earth was among the aspects of Vergilius's teachings that Boniface and Zachary considered objectionable. Others have considered this unlikely, and take the wording of Zachary's response to indicate at most an objection to belief in the existence of humans living in the antipodes. In any case, there is no record of any further action having been taken against Vergilius. He was later appointed bishop of Salzburg and was canonised in the 13th century. A possible non-literary but graphic indication that people in the Middle Ages believed that the Earth (or perhaps the world) was a sphere is the use of the orb (globus cruciger) in the regalia of many kingdoms and of the Holy Roman Empire. It is attested from the time of the Christian late-Roman emperor Theodosius II (423) throughout the Middle Ages; the Reichsapfel was used in 1191 at the coronation of emperor Henry VI. However the word orbis means "circle", and there is no record of a globe as a representation of the Earth since ancient times in the west until that of Martin Behaim in 1492. Additionally it could well be a representation of the entire "world" or cosmos. A recent study of medieval concepts of the sphericity of the Earth noted that "since the eighth century, no cosmographer worthy of note has called into question the sphericity of the Earth". However, the work of these intellectuals may not have had significant influence on public opinion, and it is difficult to tell what the wider population may have thought of the shape of the Earth if they considered the question at all. ==== Europe: High and Late Middle Ages ==== Hermann of Reichenau (1013–1054) was among the earliest Christian scholars to estimate the circumference of Earth with Eratosthenes' method. Thomas Aquinas (1225–1274), the most widely taught theologian of the Middle Ages, believed in a spherical Earth and took for granted that his readers also knew the Earth is round. Lectures in the medieval universities commonly advanced evidence in favor of the idea that the Earth was a sphere. Jill Tattersall shows that in many vernacular works in 12th- and 13th-century French texts the Earth was considered "round like a table" rather than "round like an apple". She writes, "[I]n virtually all the examples quoted ... from epics and from non-'historical' romances (that is, works of a less learned character) the actual form of words used suggests strongly a circle rather than a sphere", though she notes that even in these works the language is ambiguous. Portuguese navigation down and around the coast of Africa in the latter half of the 1400s gave wide-scale observational evidence for Earth's sphericity. In these explorations, the Sun's position moved more northward the further south the explorers travelled. Its position directly overhead at noon gave evidence for crossing the equator. These apparent solar motions in detail were more consistent with north–south curvature and a distant Sun, than with any flat-Earth explanation. The ultimate demonstration came when Ferdinand Magellan's expedition completed the first global circumnavigation in 1521. Antonio Pigafetta, one of the few survivors of the voyage, recorded the loss of a day in the course of the voyage, giving evidence for east–west curvature. ==== Middle East: Islamic scholars ==== Prior to the introduction of Greek cosmology into the Islamic world, Muslims tended to view the Earth as flat, and Muslim traditionalists who rejected Greek philosophy continued to hold to this view later on while various theologians held opposing opinions. Beginning in the 10th century onwards, some Muslim traditionalists began to adopt the notion of a spherical Earth with the influence of Greek and Ptolemaic cosmology. In Quranic cosmology, the Earth (al-arḍ) was "spread out." Whether or not this implies a flat Earth was debated by Muslims. Some modern historians believe the Quran saw the world as flat. On the other hand, the 12th-century commentary, the Tafsir al-Kabir (al-Razi) by Fakhr al-Din al-Razi argues that though this verse does describe a flat surface, it is limited in its application to local regions of the Earth which are roughly flat as opposed to the Earth as a whole. Others who would support a ball-shaped Earth included Ibn Hazm. ==== Ming Dynasty in China ==== A spherical terrestrial globe was introduced to Yuan-era Khanbaliq (i.e. Beijing) in 1267 by the Persian astronomer Jamal ad-Din, but it is not known to have made an impact on the traditional Chinese conception of the shape of the Earth. As late as 1595, an early Jesuit missionary to China, Matteo Ricci, recorded that the Ming-dynasty Chinese say: "The Earth is flat and square, and the sky is a round canopy; they did not succeed in conceiving the possibility of the antipodes." In the 17th century, the idea of a spherical Earth spread in China due to the influence of the Jesuits, who held high positions as astronomers at the imperial court. Matteo Ricci, in collaboration with Chinese cartographers and translator Li Zhizao, published the Kunyu Wanguo Quantu in 1602, the first Chinese world map based on European discoveries. The astronomical and geographical treatise Gezhicao (格致草) written in 1648 by Xiong Mingyu (熊明遇) explained that the Earth was spherical, not flat or square, and could be circumnavigated. === Myth of flat-Earth prevalence === In the 19th century, a historical myth arose which held that the predominant cosmological doctrine during the Middle Ages was that the Earth was flat. An early proponent of this myth was the American writer Washington Irving, who maintained that Christopher Columbus had to overcome the opposition of churchmen to gain sponsorship for his voyage of exploration. Later significant advocates of this view were John William Draper and Andrew Dickson White, who used it as a major element in their advocacy of the thesis that there was a long-lasting and essential conflict between science and religion. Some studies of the historical connections between science and religion have demonstrated that theories of their mutual antagonism ignore examples of their mutual support. Subsequent studies of medieval science have shown that most scholars in the Middle Ages, including those read by Christopher Columbus, maintained that the Earth was spherical. == Modern flat Earth beliefs == In the modern era, the pseudoscientific belief in a flat Earth originated with the English writer Samuel Rowbotham with the 1849 pamphlet Zetetic Astronomy. Lady Elizabeth Blount established the Universal Zetetic Society in 1893, which published journals. In 1956, Samuel Shenton set up the International Flat Earth Research Society, better known as the "Flat Earth Society" in Dover, England, as a direct descendant of the Universal Zetetic Society. In the Internet era, the availability of communications technology and social media like YouTube, Facebook and Twitter have made it easy for individuals, famous or not, to spread disinformation and attract others to erroneous ideas, including that of the flat Earth. Modern believers in a flat Earth face overwhelming publicly accessible evidence of Earth's sphericity. They also need to explain why governments, media outlets, schools, scientists, surveyors, airlines and other organizations accept that the world is spherical. To satisfy these tensions and maintain their beliefs, they generally embrace some form of conspiracy theory. In addition, believers tend to not trust observations they have not made themselves, and often distrust, disagree with or accuse each other of being in league with conspiracies. == Education == While learning from their social environment, a child's perception of their physical environment sometimes leads to a false concept about the shape of Earth and what happens beyond the horizon. Some young children think that Earth ends there and that one can fall off the edge. Education helps them gradually change their belief into a realist one of a spherical Earth. On the other hand, many children do understand that the world is round, as confirmed by interviewing what the pictures they draw actually mean. To counter misinformation about the shape of the Earth and other scientific issues, the National Center for Science Education has a site for supporting teachers. == See also == == References == === Bibliography === Garwood, Christine (2007), Flat Earth: The History of an Infamous Idea, Pan Books, ISBN 978-1-4050-4702-9 Gleede, Benjamin (2021). Antiochenische Kosmographie? Zur Begründung und Verbreitung nichtsphärischer Weltkonzeptionen in der antiken Christenheit. De Gruyter. Hatcher, William E. (1908), John Jasper, New York, NY: Fleming Revell Simek, Rudolf (1996) [1992]. Heaven and Earth in the Middle Ages: The Physical World Before Columbus. Angela Hall (trans.). The Boydell Press. ISBN 9780851156088. Retrieved February 9, 2013. Plofker, Kim (2009). Mathematics in India. Princeton University Press. ISBN 978-0691120676. Randolph, Edwin Archer (1884), The Life of Rev. John Jasper, Pastor of Sixth Mt. Zion Baptist Church, Richmond, Va., from His Birth to the Present Time, with His Theory on the Rotation of the Sun, Richmond, VA: R.T. Hill & Co. == Further reading == Fraser, Raymond (2007). When The Earth Was Flat: Remembering Leonard Cohen, Alden Nowlan, the Flat Earth Society, the King James monarchy hoax, the Montreal Story Tellers and other curious matters. Black Moss Press, ISBN 978-0-88753-439-3 == External links == Robbins, Stuart (May 1, 2012). "Episode 33: Flat Earth". Exposing PseudoAstronomy Podcast. Robbins, Stuart (September 5, 2016). "Episode 145: Modern Flat Earth Theory, Part 1". Exposing PseudoAstronomy Podcast. Robbins, Stuart (October 4, 2016). "Episode 149: Modern Flat Earth Thought, Part 2". Exposing PseudoAstronomy Podcast. Power, Myles; James, James (October 31, 2016). "Episode 146: The Lies of the Sun". League of Nerds (YouTube). Archived from the original on December 11, 2021. – Review of a pro-Flat Earth documentary. The Myth of the Flat Earth The Myth of the Flat Universe You say the earth is round? Prove it (from The Straight Dope) Flat Earth Fallacy Archived 2001-04-29 at the Wayback Machine Zetetic Astronomy, or Earth Not a Globe by Parallax (Samuel Birley Rowbotham (1816–1884)) at sacred-texts.com Flat Earth idea of the Suns trajectory Flat Earth Theory of the Moon & Sun's paths around the world
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Marketing science is a field that approaches marketing—the understanding of customer needs, and the development of approaches by which they might be fulfilled—predominantly through scientific methods, rather than through tools and techniques common with research in the arts or humanities. The field of marketing science, in the pursuit of "truths" in marketing, is related to, but more general than marketing research, which is oriented towards a specific product, service or campaign. The earliest published works in Marketing Science are by Frank Bass and John Little . The two are considered to be the founders of the field of Marketing Science. Before marketing science was formally labeled, its activity appeared as management science within the marketing framework. The interaction between academics and practitioners in marketing science dates back to 1961, with the founding of the Marketing Science Institute. Interest in marketing science as a field grew in the late 1980s and early 1990s as electronic point-of-sale data grew and barcode readers led to a "marketing information revolution". Before conferences were organized with a "marketing science" label, four meetings were convened as "Market Measurement and Analysis" conferences from 1979 to 1982, sponsored by The Institute of Management Sciences and the Operations Research Society of America. The first officially labeled Marketing Science Conference was hosted by the School of Management at UCLA in 1983. == Marketing science and Big Data == The marketing profession has long relied on data. But as the data flood gets bigger, progressive marketers are turning to big data analysis methods as well as systematic observation, testing and measurement to study broad behavioral patterns, drill down from the aggregate to the individual and produce new insights that improve business outcomes. == References ==
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The science of value, or value science, is a creation of philosopher Robert S. Hartman, which attempts to formally elucidate value theory using both formal and symbolic logic. == Fundamentals == The fundamental principle, which functions as an axiom, and can be stated in symbolic logic, is that a thing is good insofar as it exemplifies its concept. To put it another way, "a thing is good if it has all its descriptive properties." This means, according to Hartman, that the good thing has a name, that the name has a meaning defined by a set of properties, and that the thing possesses all of the properties in the set. A thing is bad if it does not fulfill its description. He introduces three basic dimensions of value, systemic, extrinsic and intrinsic for sets of properties—perfection is to systemic value what goodness is to extrinsic value and what uniqueness is to intrinsic value—each with their own cardinality: finite, ℵ 0 {\displaystyle \aleph _{0}} and ℵ 1 {\displaystyle \aleph _{1}} . In practice, the terms "good" and "bad" apply to finite sets of properties, since this is the only case where there is a ratio between the total number of desired properties and the number of such properties possessed by some object being valued. (In the case where the number of properties is countably infinite, the extrinsic dimension of value, the exposition as well as the mere definition of a specific concept is taken into consideration.) Hartman quantifies this notion by the principle that each property of the thing is worth as much as each other property, depending on the level of abstraction. Hence, if a thing has n properties, each of them—if on the same level of abstraction—is proportionally worth n−1. == Infinite sets of properties == Hartman goes on to consider infinite sets of properties. Hartman claims that according to a theorem of transfinite mathematics, any collection of material objects is at most denumerably infinite. This is not, in fact, a theorem of mathematics. But, according to Hartman, people are capable of a denumerably infinite set of predicates, intended in as many ways, which he gives as ℵ 1 {\displaystyle \aleph _{1}} . As this yields a notional cardinality of the continuum, Hartman advises that when setting out to describe a person, a continuum of properties would be most fitting and appropriate to bear in mind. This is the cardinality of intrinsic value in Hartman's system. Although they play no role in ordinary mathematics, Hartman deploys the notion of aleph number reciprocals, as a sort of infinitesimal proportion. This, he contends goes to zero in the limit as the uncountable cardinals become larger. In Hartman's calculus, for example, the assurance in a Dear John letter, that "we will always be friends" has axiological value 1 ℵ 2 {\displaystyle {\frac {_{1}}{\aleph _{2}}}} , whereas taking a metaphor literally would be slightly preferable, the reification having a value of 1 ℵ 1 {\displaystyle {\frac {_{1}}{\aleph _{1}}}} . == Notes == == References == Davis, John William, ed, Value and Valuation: Axiological Studies in Honor of Robert S. Hartman, The University of Tennessee Press, 1972 Hartman, Robert S., The Structure of Value: Foundations of Scientific Axiology, Southern Illinois University Press, 1967 Hartman, Robert S., "Application of the Science of Axiology," Ch. IX in Rem B. Edwards and John W. Davis, eds., Forms of Value and Valuation: Theory and Applications. Lanham, Md., University Press of America, 1991 Hartman, Robert S., Freedom to Live, (Arthur R. Ellis, editor), Atlanta: Rodopi Editions, Value Inquiry Book Series, 1984, reissued 1994 Hartman, Robert S., "Axiometric Structure of Intrinsic Value", Journal of Value Inquiry (Summer, 1974; v.8, no. 2, pp. 88–101 Katz, Marvin C., Sciences of Man and Social Ethics, Boston, 1969, esp. pp. 9–45, 101–123. Katz, Marvin C., Trends Towards Synthesis in the Philosophy of Robert S. Hartman, Muskegon: Axiopress (142 pages 2004). == External links == Hartman Institute Axiometrics International, Incorporated--30 years of applied research Center for Applied AxioMetrics How intangible values can actually be measured Value Insights-What is Value Science?
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Laser science or laser physics is a branch of optics that describes the theory and practice of lasers. Laser science is principally concerned with quantum electronics, laser construction, optical cavity design, the physics of producing a population inversion in laser media, and the temporal evolution of the light field in the laser. It is also concerned with the physics of laser beam propagation, particularly the physics of Gaussian beams, with laser applications, and with associated fields such as nonlinear optics and quantum optics. == History == Laser science predates the invention of the laser itself. Albert Einstein created the foundations for the laser and maser in 1917, via a paper in which he re-derived Max Planck’s law of radiation using a formalism based on probability coefficients (Einstein coefficients) for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation. The existence of stimulated emission was confirmed in 1928 by Rudolf W. Ladenburg. In 1939, Valentin A. Fabrikant made the earliest laser proposal. He specified the conditions required for light amplification using stimulated emission. In 1947, Willis E. Lamb and R. C. Retherford found apparent stimulated emission in hydrogen spectra and effected the first demonstration of stimulated emission; in 1950, Alfred Kastler (Nobel Prize for Physics 1966) proposed the method of optical pumping, experimentally confirmed, two years later, by Brossel, Kastler, and Winter. The theoretical principles describing the operation of a microwave laser (a maser) were first described by Nikolay Basov and Alexander Prokhorov at the All-Union Conference on Radio Spectroscopy in May 1952. The first maser was built by Charles H. Townes, James P. Gordon, and Herbert J. Zeiger in 1953. Townes, Basov and Prokhorov were awarded the Nobel Prize in Physics in 1964 for their research in the field of stimulated emission. Arthur Ashkin, Gérard Mourou, and Donna Strickland were awarded the Nobel Prize in Physics in 2018 for groundbreaking inventions in the field of laser physics. The first working laser (a pulsed ruby laser) was demonstrated on May 16, 1960, by Theodore Maiman at the Hughes Research Laboratories. == See also == Laser acronyms List of laser types == References == == External links == A very detailed tutorial on lasers
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https://en.wikipedia.org/wiki/Laser_science
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In natural and social science research, a protocol is most commonly a predefined procedural method in the design and implementation of an experiment. Protocols are written whenever it is desirable to standardize a laboratory method to ensure successful replication of results by others in the same laboratory or by other laboratories. Additionally, and by extension, protocols have the advantage of facilitating the assessment of experimental results through peer review. In addition to detailed procedures, equipment, and instruments, protocols will also contain study objectives, reasoning for experimental design, reasoning for chosen sample sizes, safety precautions, and how results were calculated and reported, including statistical analysis and any rules for predefining and documenting excluded data to avoid bias. Similarly, a protocol may refer to the procedural methods of health organizations, commercial laboratories, manufacturing plants, etc. to ensure their activities (e.g., blood testing at a hospital, testing of certified reference materials at a calibration laboratory, and manufacturing of transmission gears at a facility) are consistent to a specific standard, encouraging safe use and accurate results. Finally, in the field of social science, a protocol may also refer to a "descriptive record" of observed events or a "sequence of behavior" of one or more organisms, recorded during or immediately after an activity (e.g., how an infant reacts to certain stimuli or how gorillas behave in natural habitat) to better identify "consistent patterns and cause-effect relationships." These protocols may take the form of hand-written journals or electronically documented media, including video and audio capture. == Experiment and study protocol == Various fields of science, such as environmental science and clinical research, require the coordinated, standardized work of many participants. Additionally, any associated laboratory testing and experiment must be done in a way that is both ethically sound and results can be replicated by others using the same methods and equipment. As such, rigorous and vetted testing and experimental protocols are required. In fact, such predefined protocols are an essential component of Good Laboratory Practice (GLP) and Good Clinical Practice (GCP) regulations. Protocols written for use by a specific laboratory may incorporate or reference standard operating procedures (SOP) governing general practices required by the laboratory. A protocol may also reference applicable laws and regulations that are applicable to the procedures described. Formal protocols typically require approval by one or more individuals—including for example a laboratory directory, study director, and/or independent ethics committee: 12 —before they are implemented for general use. Clearly defined protocols are also required by research funded by the National Institutes of Health. In a clinical trial, the protocol is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by research staff to monitor their health and to determine the safety and effectiveness of their treatment. Since 1996, clinical trials conducted are widely expected to conform to and report the information called for in the CONSORT Statement, which provides a framework for designing and reporting protocols. Though tailored to health and medicine, ideas in the CONSORT statement are broadly applicable to other fields where experimental research is used. Protocols will often address: safety: Safety precautions are a valuable addition to a protocol, and can range from requiring goggles to provisions for containment of microbes, environmental hazards, toxic substances, and volatile solvents. Procedural contingencies in the event of an accident may be included in a protocol or in a referenced SOP. procedures: Procedural information may include not only safety procedures but also procedures for avoiding contamination, calibration of equipment, equipment testing, documentation, and all other relevant issues. These procedural protocols can be used by skeptics to invalidate any claimed results if flaws are found. equipment used: Equipment testing and documentation includes all necessary specifications, calibrations, operating ranges, etc. Environmental factors such as temperature, humidity, barometric pressure, and other factors can often have effects on results. Documenting these factors should be a part of any good procedure. reporting: A protocol may specify reporting requirements. Reporting requirements would include all elements of the experiments design and protocols and any environmental factors or mechanical limitations that might affect the validity of the results. calculations and statistics: Protocols for methods that produce numerical results generally include detailed formulas for calculation of results. A formula may also be included for preparation of reagents and other solutions required for the work. Methods of statistical analysis may be included to guide interpretation of the data. bias: Many protocols include provisions for avoiding bias in the interpretation of results. Approximation error is common to all measurements. These errors can be absolute errors from limitations of the equipment or propagation errors from approximate numbers used in calculations. Sample bias is the most common and sometimes the hardest bias to quantify. Statisticians often go to great lengths to ensure that the sample used is representative. For instance political polls are best when restricted to likely voters and this is one of the reasons why web polls cannot be considered scientific. The sample size is another important concept and can lead to biased data simply due to an unlikely event. A sample size of 10, i.e., polling 10 people, will seldom give valid polling results. Standard deviation and variance are concepts used to quantify the likely relevance of a given sample size. The placebo effect and observer bias often require the blinding of patients and researchers as well as a control group. Best practice recommends publishing the protocol of the review before initiating it to reduce the risk of unplanned research duplication and to enable transparency, and consistency between methodology and protocol. === Blinded protocols === A protocol may require blinding to avoid bias. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constrains. During the course of an experiment, a participant becomes unblinded if they deduce or otherwise obtain information that has been masked to them. Unblinding that occurs before the conclusion of a study is a source of experimental error, as the bias that was eliminated by blinding is re-introduced. Unblinding is common in blind experiments, and must be measured and reported. Reporting guidelines recommend that all studies assess and report unblinding. In practice, very few studies assess unblinding. An experimenter may have latitude defining procedures for blinding and controls but may be required to justify those choices if the results are published or submitted to a regulatory agency. When it is known during the experiment which data was negative there are often reasons to rationalize why that data shouldn't be included. Positive data are rarely rationalized the same way. == See also == == References ==
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https://en.wikipedia.org/wiki/Protocol_(science)
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Scientific misconduct is the violation of the standard codes of scholarly conduct and ethical behavior in the publication of professional scientific research. It is the violation of scientific integrity: violation of the scientific method and of research ethics in science, including in the design, conduct, and reporting of research. A Lancet review on Handling of Scientific Misconduct in Scandinavian countries provides the following sample definitions, reproduced in The COPE report 1999: Danish definition: "Intention or gross negligence leading to fabrication of the scientific message or a false credit or emphasis given to a scientist" Swedish definition: "Intention[al] distortion of the research process by fabrication of data, text, hypothesis, or methods from another researcher's manuscript form or publication; or distortion of the research process in other ways." The consequences of scientific misconduct can be damaging for perpetrators and journal audiences and for any individual who exposes it. In addition there are public health implications attached to the promotion of medical or other interventions based on false or fabricated research findings. Scientific misconduct can result in loss of public trust in the integrity of science. Three percent of the 3,475 research institutions that report to the US Department of Health and Human Services' Office of Research Integrity indicate some form of scientific misconduct. However the ORI will only investigate allegations of impropriety where research was funded by federal grants. They routinely monitor such research publications for red flags and their investigation is subject to a statute of limitations. Other private organizations like the Committee of Medical Journal Editors (COJE) can only police their own members. == Motivation == According to David Goodstein of Caltech, there are motivators for scientists to commit misconduct, which are briefly summarised here. Career pressure Science is still a very strongly career-driven discipline. Scientists depend on a good reputation to receive ongoing support and funding, and a good reputation relies largely on the publication of high-profile scientific papers. Hence, there is a strong imperative to "publish or perish". This pressure is stronger in some research settings than others, contributing to the impression that misconduct may be more prevalent in some parts of the world than others. This may motivate desperate (or fame-hungry) scientists to fabricate results. Ease of fabrication In many scientific fields, results are often difficult to reproduce accurately, being obscured by noise, artifacts, and other extraneous data. That means that even if a scientist does falsify data, they can expect to get away with it – or at least claim innocence if their results conflict with others in the same field. There are few strongly backed systems to investigate possible violations, attempt to press charges, or punish deliberate misconduct. It is relatively easy to cheat although difficult to know exactly how many scientists fabricate data. Monetary Gain In many scientific fields, the most lucrative options for professionals are often selling opinions. Corporations can pay experts to support products directly or indirectly via conferences. Psychologists can make money by repeatedly acting as an expert witness in custody proceedings for the same law firms. == Forms == The U.S. National Science Foundation defines three types of research misconduct: fabrication, falsification, and plagiarism. Fabrication is making up results and recording or reporting them. This is sometimes referred to as "drylabbing". A more minor form of fabrication is where references are included to give arguments the appearance of widespread acceptance, but are actually fake, or do not support the argument. Falsification is manipulating research materials, equipment, or processes or changing or omitting data or results such that the research is not accurately represented in the research record. Plagiarism is the appropriation of another person's ideas, processes, results, or words without giving appropriate credit. One form is the appropriation of the ideas and results of others, and publishing as to make it appear the author had performed all the work under which the data was obtained. A subset is citation plagiarism – willful or negligent failure to appropriately credit other or prior discoverers, so as to give an improper impression of priority. This is also known as, "citation amnesia", the "disregard syndrome" and "bibliographic negligence". Arguably, this is the most common type of scientific misconduct. Sometimes it is difficult to guess whether authors intentionally ignored a highly relevant cite or lacked knowledge of the prior work. Discovery credit can also be inadvertently reassigned from the original discoverer to a better-known researcher. This is a special case of the Matthew effect. Plagiarism-fabrication – the act of taking an unrelated figure from an unrelated publication and reproducing it exactly in a new publication, claiming that it represents new data. Self-plagiarism – or multiple publication of the same content with different titles or in different journals is sometimes also considered misconduct; scientific journals explicitly ask authors not to do this. It is referred to as "salami" (i.e. many identical slices) in the jargon of medical journal editors. According to some editors, this includes publishing the same article in a different language. Other types of research misconduct are also recognized: Ghostwriting describes when someone other than the named author(s) makes a major contribution to the research. Sometimes, this is done to mask contributions from authors with a conflict of interest. In other cases, a ghost authorship occurs where the ghost author sells the research paper to a colleague who wants the publication in order to boost their publishing metrics. Guest authorship is the phenomenon wherein authorship is given to someone who has not made any substantial contribution. This can be done by senior researchers who muscle their way onto the papers of inexperienced junior researchers as well as others that stack authorship in an effort to guarantee publication. This is much harder to prove due to a lack of consistency in defining "authorship" or "substantial contribution". Scientific misconduct can also occur during the peer-review process by a reviewer or editor with a conflict of interest. Reviewer-coerced citation can also inflate the perceived citation impact of a researcher's work and their reputation in the scientific community, similar to excessive self-citation. Reviewers are expected to be impartial and assess the quality of their work. They are expected to declare a conflict of interest to the editors if they are colleagues or competitors of the authors. A rarer case of scientific misconduct is editorial misconduct, where an editor does not declare conflicts of interest, creates pseudonyms to review papers, gives strongly worded editorial decisions to support reviews suggesting to add excessive citations to their own unrelated works or to add themselves as a co-author or their name to the title of the manuscript. Publishing in a predatory journal, knowingly or unknowingly, was discussed as a form of potential scientific misconduct. The peer-review process can have limitations when considering research outside the conventional scientific paradigm: social factors such as "groupthink" can interfere with open and fair deliberation of new research. Sneaked references is the act of subtly embedding references that are not present in a manuscript in the metadata of this accepted manuscript without the original authors being capable of noticing or correcting such modifications. Peer review manipulation. Many journals invite authors to recommend a list of suitable peer reviewers, along with their contact information. In some cases, authors recommend a reviewer for whom they provide a fake email address that in fact belongs to the author. If the editor follows the author's reviewer recommendation, the reviewer can then write their own review. === Photo manipulation === Compared to other forms of scientific misconduct, image fraud (manipulation of images to distort their meaning) is of particular interest since it can frequently be detected by external parties. In 2006, the Journal of Cell Biology gained publicity for instituting tests to detect photo manipulation in papers that were being considered for publication. This was in response to the increased usage of programs such as Adobe Photoshop by scientists, which facilitate photo manipulation. Since then more publishers, including the Nature Publishing Group, have instituted similar tests and require authors to minimize and specify the extent of photo manipulation when a manuscript is submitted for publication. However, there is little evidence to indicate that such tests are applied rigorously. One Nature paper published in 2009 has subsequently been reported to contain around 20 separate instances of image fraud. Although the type of manipulation that is allowed can depend greatly on the type of experiment that is presented and also differ from one journal to another, in general the following manipulations are not allowed: splicing together different images to represent a single experiment changing brightness and contrast of only a part of the image any change that conceals information, even when it is considered to be non-specific, which includes: changing brightness and contrast to leave only the most intense signal using clone tools to hide information showing only a very small part of the photograph so that additional information is not visible Image manipulations are typically done on visually repetitive images such as those of blots and microscope images. === Helicopter research === == Responsibilities == === Authorship responsibility === All authors of a scientific publication are expected to have made reasonable attempts to check findings submitted to academic journals for publication. Simultaneous submission of scientific findings to more than one journal or duplicate publication of findings is usually regarded as misconduct, under what is known as the Ingelfinger rule, named after the editor of The New England Journal of Medicine 1967–1977, Franz Ingelfinger. Guest authorship (where there is stated authorship in the absence of involvement, also known as gift authorship) and ghost authorship (where the real author is not listed as an author) are commonly regarded as forms of research misconduct. In some cases coauthors of faked research have been accused of inappropriate behavior or research misconduct for failing to verify reports authored by others or by a commercial sponsor. Examples include the case of Gerald Schatten who co-authored with Hwang Woo-Suk, the case of Professor Geoffrey Chamberlain named as guest author of papers fabricated by Malcolm Pearce, (Chamberlain was exonerated from collusion in Pearce's deception) – and the coauthors with Jan Hendrik Schön at Bell Laboratories. More recent cases include that of Charles Nemeroff, then the editor-in-chief of Neuropsychopharmacology, and a well-documented case involving the drug Actonel. Authors are expected to keep all study data for later examination even after publication. The failure to keep data may be regarded as misconduct. Some scientific journals require that authors provide information to allow readers to determine whether the authors might have commercial or non-commercial conflicts of interest. Authors are also commonly required to provide information about ethical aspects of research, particularly where research involves human or animal participants or use of biological material. Provision of incorrect information to journals may be regarded as misconduct. Financial pressures on universities have encouraged this type of misconduct. The majority of recent cases of alleged misconduct involving undisclosed conflicts of interest or failure of the authors to have seen scientific data involve collaborative research between scientists and biotechnology companies. === Research institution responsibility === In general, defining whether an individual is guilty of misconduct requires a detailed investigation by the individual's employing academic institution. Such investigations require detailed and rigorous processes and can be extremely costly. Furthermore, the more senior the individual under suspicion, the more likely it is that conflicts of interest will compromise the investigation. In many countries (with the notable exception of the United States) acquisition of funds on the basis of fraudulent data is not a legal offence and there is consequently no regulator to oversee investigations into alleged research misconduct. Universities therefore have few incentives to investigate allegations in a robust manner, or act on the findings of such investigations if they vindicate the allegation. Well publicised cases illustrate the potential role that senior academics in research institutions play in concealing scientific misconduct. A King's College (London) internal investigation showed research findings from one of their researchers to be 'at best unreliable, and in many cases spurious' but the college took no action, such as retracting relevant published research or preventing further episodes from occurring. In a more recent case an internal investigation at the National Centre for Cell Science (NCCS), Pune determined that there was evidence of misconduct by Gopal Kundu, but an external committee was then organised which dismissed the allegation, and the NCCS issued a memorandum exonerating the authors of all charges of misconduct. Undeterred by the NCCS exoneration, the relevant journal (Journal of Biological Chemistry) withdrew the paper based on its own analysis. === Scientific peer responsibility === Some academics believe that scientific colleagues who suspect scientific misconduct should consider taking informal action themselves, or reporting their concerns. This question is of great importance since much research suggests that it is very difficult for people to act or come forward when they see unacceptable behavior, unless they have help from their organizations. A "User-friendly Guide" and the existence of a confidential organizational ombudsman may help people who are uncertain about what to do, or afraid of bad consequences for their speaking up. === Responsibility of journals === Journals are responsible for safeguarding the research record and hence have a critical role in dealing with suspected misconduct. This is recognised by the Committee on Publication Ethics (COPE), which has issued clear guidelines on the form (e.g. retraction) that concerns over the research record should take. The COPE guidelines state that journal editors should consider retracting a publication if they have clear evidence that the findings are unreliable, either as a result of misconduct (e.g. data fabrication) or honest error (e.g. miscalculation or experimental error). Retraction is also appropriate in cases of redundant publication, plagiarism and unethical research. Journal editors should consider issuing an expression of concern if they receive inconclusive evidence of research or publication misconduct by the authors, there is evidence that the findings are unreliable but the authors' institution will not investigate the case, they believe that an investigation into alleged misconduct related to the publication either has not been, or would not be, fair and impartial or conclusive, or an investigation is underway but a judgement will not be available for a considerable time. Journal editors should consider issuing a correction if a small portion of an otherwise reliable publication proves to be misleading (especially because of honest error), or the author / contributor list is incorrect (i.e. a deserving author has been omitted or somebody who does not meet authorship criteria has been included). Evidence emerged in 2012 that journals learning of cases where there is strong evidence of possible misconduct, with issues potentially affecting a large portion of the findings, frequently fail to issue an expression of concern or correspond with the host institution so that an investigation can be undertaken. In one case, Nature allowed a corrigendum to be published despite clear evidence of image fraud. Subsequent retraction of the paper required the actions of an independent whistleblower. The cases of Joachim Boldt and Yoshitaka Fujii in anaesthesiology focussed attention on the role that journals play in perpetuating scientific fraud as well as how they can deal with it. In the Boldt case, the editors-in-chief of 18 specialist journals (generally anesthesia and intensive care) made a joint statement regarding 88 published clinical trials conducted without Ethics Committee approval. In the Fujii case, involving nearly 200 papers, the journal Anesthesia & Analgesia, which published 24 of Fujii's papers, has accepted that its handling of the issue was inadequate. Following publication of a letter to the editor from Kranke and colleagues in April 2000, along with a non-specific response from Dr. Fujii, there was no follow-up on the allegation of data manipulation and no request for an institutional review of Dr. Fujii's research. Anesthesia & Analgesia went on to publish 11 additional manuscripts by Dr. Fujii following the 2000 allegations of research fraud, with Editor Steven Shafer stating in March 2012 that subsequent submissions to the journal by Dr. Fujii should not have been published without first vetting the allegations of fraud. In April 2012 Shafer led a group of editors to write a joint statement, in the form of an ultimatum made available to the public, to a large number of academic institutions where Fujii had been employed, offering these institutions the chance to attest to the integrity of the bulk of the allegedly fraudulent papers. == Consequences of scientific misconduct == === Consequences for science === The consequences of scientific fraud vary based on the severity of the fraud, the level of notice it receives, and how long it goes undetected. For cases of fabricated evidence, the consequences can be wide-ranging, with others working to confirm (or refute) the false finding, or with research agendas being distorted to address the fraudulent evidence. The Piltdown Man fraud is a case in point: The significance of the bona-fide fossils that were being found was muted for decades because they disagreed with Piltdown Man and the preconceived notions that those faked fossils supported. In addition, the prominent paleontologist Arthur Smith Woodward spent time at Piltdown each year until he died, trying to find more Piltdown Man remains. The misdirection of resources kept others from taking the real fossils more seriously and delayed the reaching of a correct understanding of human evolution. (The Taung Child, which should have been the death knell for the view that the human brain evolved first, was instead treated very critically because of its disagreement with the Piltdown Man evidence.) In the case of Prof. Don Poldermans, the misconduct occurred in reports of trials of treatment to prevent death and myocardial infarction in patients undergoing operations. The trial reports were relied upon to issue guidelines that applied for many years across North America and Europe. In the case of Dr Alfred Steinschneider, two decades and tens of millions of research dollars were lost trying to find the elusive link between infant sleep apnea, which Steinschneider said he had observed and recorded in his laboratory, and sudden infant death syndrome (SIDS), of which he stated it was a precursor. The cover was blown in 1994, 22 years after Steinschneider's 1972 Pediatrics paper claiming such an association, when Waneta Hoyt, the mother of the patients in the paper, was arrested, indicted and convicted on five counts of second-degree murder for the smothering deaths of her five children. While that in itself was bad enough, the paper, presumably written as an attempt to save infants' lives, ironically was ultimately used as a defense by parents suspected in multiple deaths of their own children in cases of Münchausen syndrome by proxy. The 1972 Pediatrics paper was cited in 404 papers in the interim and is still listed on PubMed without comment. === Consequences for those who expose misconduct === The potentially severe consequences for individuals who are found to have engaged in misconduct also reflect on the institutions that host or employ them and also on the participants in any peer review process that has allowed the publication of questionable research. This means that a range of actors in any case may have a motivation to suppress any evidence or suggestion of misconduct. Persons who expose such cases, commonly called whistleblowers, find themselves open to retaliation by a number of different means. These negative consequences for exposers of misconduct have driven the development of whistle blowers charters – designed to protect those who raise concerns (for more details refer to retaliation (law)). === Regulatory Violations and Consequences (example) === Title 10 Code of Federal Regulation (CFR) Part 50.5, Deliberate Misconduct of the U.S. Nuclear Regulatory Commission (NRC) regulations, addresses the prohibition of certain activities by individual involved in NRC-licensed activities. 10 CFR 50.5 is designed to ensure the safety and integrity of nuclear operations. 10 CFR Part 50.9, Completeness and Accuracy of Information, focuses on the requirements for providing information and data to the NRC. The intent of 10 CFR 50.5 is to deter and penalize intentional wrongdoing (i.e., violations). 10 CFR 50.9 is crucial in maintaining transparency and reliability in the nuclear industry, which effectively emphasizes honesty and integrity in maintaining the safety and security of nuclear operations. Providing false or misleading information or data to the NRC is therefore a violation of 10 CFR 50.9. Violation of any of these rules can lead to severe penalties, including termination, fines and criminal prosecution. It can also result in the revocation of licenses or certifications, thereby barring individuals or entities from participating in any NRC-licensed activities in the future. == Data issues == === Exposure of fraudulent data === With the advancement of the internet, there are now several tools available to aid in the detection of plagiarism and multiple publication within biomedical literature. One tool developed in 2006 by researchers in Dr. Harold Garner's laboratory at the University of Texas Southwestern Medical Center at Dallas is Déjà vu, an open-access database containing several thousand instances of duplicate publication. All of the entries in the database were discovered through the use of text data mining algorithm eTBLAST, also created in Dr. Garner's laboratory. The creation of Déjà vu and the subsequent classification of several hundred articles contained therein have ignited much discussion in the scientific community concerning issues such as ethical behavior, journal standards, and intellectual copyright. Studies within this database have been published in journals such as Nature and Science, among others. Other tools which may be used to detect fraudulent data include error analysis. Measurements generally have a small amount of error, and repeated measurements of the same item will generally result in slight differences in readings. These differences can be analyzed, and follow certain known mathematical and statistical properties. Should a set of data appear to be too faithful to the hypothesis, i.e., the amount of error that would normally be in such measurements does not appear, a conclusion can be drawn that the data may have been forged. Error analysis alone is typically not sufficient to prove that data have been falsified or fabricated, but it may provide the supporting evidence necessary to confirm suspicions of misconduct. === Data sharing === Kirby Lee and Lisa Bero suggest, "Although reviewing raw data can be difficult, time-consuming and expensive, having such a policy would hold authors more accountable for the accuracy of their data and potentially reduce scientific fraud or misconduct." == Underreporting == The vast majority of cases of scientific misconduct may not be reported. The number of article retractions in 2022 was nearly 5,500, but Ivan Oransky and Adam Marcus, co-founders of Retraction Watch, estimate that at least 100,000 retractions should occur every year, with only about one in five being due to "honest error". == Some notable cases == In 1998 Andrew Wakefield published a fraudulent research paper in The Lancet claiming links between the MMR vaccine, autism, and inflammatory bowel disease. In 2010, he was found guilty of dishonesty in his research and banned from medicine by the UK General Medical Council following an investigation by Brian Deer of the London Sunday Times. The claims in Wakefield's paper were widely reported, leading to a sharp drop in vaccination rates in the UK and Ireland and outbreaks of mumps and measles. Promotion of the claimed link continues to fuel the anti-vaccination movement. In 2011 Diederik Stapel, a highly regarded Dutch social psychologist was discovered to have fabricated data in dozens of studies on human behaviour. He has been called "the biggest con man in academic science". In 2020, Sapan Desai and his coauthors published two papers in the prestigious medical journals The Lancet and The New England Journal of Medicine, early in the COVID-19 pandemic. The papers were based on a very large dataset published by Surgisphere, a company owned by Desai. The dataset was exposed as a fabrication, and the papers were soon retracted. In 2024, Eliezer Masliah, head of the Division of Neuroscience at the National Institute on Aging, was suspected of having manipulated and inappropriately reused images in over 100 scientific papers spanning several decades, including those that were used by the FDA to greenlight testing for the experimental drug prasinezumab as a treatment for Parkinson's. == Solutions == === Changing research assessment === Since 2012, the Declaration on Research Assessment (DORA), from San Francisco, gathered many institutions, publishers, and individuals committing to improving the metrics used to assess research and to stop focusing on the journal impact factor. == See also == == References == == Further reading == Claus Emmeche. "An old and a recent example of scientific fraud" (PowerPoint). Retrieved 2007-05-18. Sam Kean (2021). The Icepick Surgeon: Murder, Fraud, Sabotage, Piracy, and Other Dastardly Deeds Perpetrated in the Name of Science. Little, Brown and Company. ISBN 978-0316496506. Patricia Keith-Spiegel, Joan Sieber, and Gerald P. Koocher (November, 2010). Responding to Research Wrongdoing: A User Friendly Guide. Jargin SV. Misconduct in Medical Research and Practice. Nova Science Publishers, 2020. https://novapublishers.com/shop/misconduct-in-medical-research-and-practice/ == External links == Media related to Scientific misconduct at Wikimedia Commons Publication ethics checklist (PDF) (for routine use during manuscript submission to a scientific journal)
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https://en.wikipedia.org/wiki/Scientific_misconduct
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A Master of Science (Latin: Magister Scientiae; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree. In contrast to the Master of Arts degree, the Master of Science degree is typically granted for studies in sciences, engineering and medicine and is usually for programs that are more focused on scientific and mathematical subjects; however, different universities have different conventions and may also offer the degree for fields typically considered within the humanities and social sciences. While it ultimately depends upon the specific program, earning a Master of Science degree typically includes writing a thesis. The Master of Science degree was introduced at the University of Michigan in 1858. One of the first recipients of the degree was De Volson Wood, who was conferred a Master of Science degree at the University of Michigan in 1859. == Algeria == Algeria follows the Bologna Process. == Australia == Australian universities commonly have coursework or research-based Master of Science courses for graduate students. They typically run for 1–2 years full-time, with varying amounts of research involved. == Bangladesh == All Bangladeshi private and public universities have Master of Science courses as postgraduate degree. These include most of the major state-owned colleges. A number of private colleges also do offer MS degrees. After passing Bachelor of Science, any student becomes eligible to study in this discipline. == Belgium == Like all EU member states, Belgium follows the Bologna Process. In Belgium, the typical university track involved obtaining two degrees, being a two-year Kandidaat prerequisite track (replaced by Bachelor) followed by a two- or three-year Licentiaat track. The latter was replaced by the Master of Science (M.Sc.) academic degree. This system was not exclusive to scientific degrees and was also used for other programs like law and literature. == Canada == In Canada, Master of Science (MSc) degrees may be entirely course-based, entirely research-based or (more typically) a mixture. Master's programs typically take one to three years to complete and the completion of a scientific thesis is often required. Admission to a master's program is contingent upon holding a four-year university bachelor's degree. Some universities require a master's degree in order to progress to a doctoral program (PhD). === Quebec === In the province of Quebec, the Master of Science follows the same principles as in the rest of Canada. There is one exception, however, regarding admission to a master's program. Since Québécois students complete two to three years of college before entering university, they have the opportunity to complete a bachelor's degree in three years instead of four. Some undergraduate degrees such as the Bachelor of Education and the Bachelor of Engineering requires four years of study. Following the obtention of their bachelor's degree, students can be admitted into a graduate program to eventually obtain a master's degree. While some students complete their master's program, others use it as a bridge to doctoral research programs. After one year of study and research in the master's program, many students become eligible to apply to a Doctor of Philosophy (Ph.D.) program directly, without obtaining the Master of Science degree in the first place. == Chile == Commonly the Chilean universities have used "Magíster" for a master's degree, but other than that is similar to the rest of South America. == Cyprus == Like all EU member states, the Republic of Cyprus follow the Bologna Process. Universities in Cyprus have used either "Magíster Scientiae or Artium" or Master of Arts/Science for a master's degree with 90 to 120 ECTS and duration of studies between 1, 2 and 5 years. == Czech Republic and Slovakia == Like all EU member states, Czech Republic and Slovakia follow the Bologna Process. Czech Republic and Slovakia both award two different types of master's degrees; both award a title of Mgr. or Ing. to be used before the name. Prior to reforms for compliance with the Bologna process, a master's degree could only be obtained after 5 years of uninterrupted study. Under the new system, it takes only 2 years but requires a previously completed 3-year bachelor's program (a Bc. title). Writing a thesis (in both master's and bachelor's programs) and passing final exams are necessary to obtain the degree. It is mostly the case that the final exams cover the main study areas of the whole study program, i.e. a student is required to prove their knowledge in the subjects they attended during the 2 resp. 3 years of their study. Exams also include the defence of a thesis before an academic board. Ing. (Engineer) degrees are usually awarded for master's degrees achieved in the Natural Sciences or Mathematics-heavy study programmes, whereas an Mgr. (Magister) is generally awarded for Master's studies in social sciences, humanities and the arts. == Egypt == The Master of Science (M.Sc.) is an academic degree for post-graduate candidates or researchers, it usually takes from 4 to 7 years after passing the Bachelor of Science (B.Sc.) degree. Master programs are awarded in many sciences in the Egyptian Universities. A completion of the degree requires finishing a pre-master studies followed by a scientific thesis or research. All M.Sc. degree holders are allowable to take a step forward in the academic track to get the PhD degree. == Finland == Like all EU member states, Finland follows the Bologna Process. The Master of Science (M.Sc.) academic degree usually follows the Bachelor of Science (B.Sc.) studies which typically last five years. For the completion of both the bachelor and the master studies the student must accumulate a total of 300 ECTS credits, thus most Masters programs are two-year programs with 120 credits. The completion of a scientific thesis is required. == Germany == Like all EU member states, Germany follows the Bologna Process. The Master of Science (M.Sc.) academic degree replaces the once common Diplom or Magister programs that typically lasted four to five years. It is awarded in science-related studies with a high percentage of mathematics. For the completion the student must accumulate 300 ECTS Credits, thus most Masters programs are two-year programs with 120 credits. The completion of a scientific thesis is required. == South America == In Argentina, Brazil, Colombia, Ecuador, Mexico, Panama, Peru, Uruguay and Venezuela, the Master of Science or Magister is a postgraduate degree lasting two to four years. The admission to a master's program (Spanish: Licenciatura; Portuguese: Mestrado) requires the full completion of a four to five year long undergraduate degree, bachelor's degree, engineer's degree or a licentiate of the same length. Defense of a research thesis is required. All master's degrees qualify for a doctorate program. Depending on the country, one ECTS credit point can equal on average between 22 and 30 actual study hours. In most of these cases, the number of required attendance hours to the university classes will be at least half of that (one ECTS will mean around 11 to 15 mandatory hours of on-site classes). == Southeastern Europe == In Slavic countries in European southeast (particularly former Yugoslavian republics), the education system was largely based on the German university system (largely due to the presence and influence of the Austria-Hungary Empire in the region). Prior to the implementation of the Bologna Process, academic university studies comprised a 4–5 year-long graduate diplom program, which could have been followed by a 2–4 year long magistar program and then later with 2–5 year long doctor of science program. After the Bologna Process implementation, again based on the German implementation, Diplom titles and programs were replaced by entirely professional bachelor's and master's programs. The studies are structured such that a master program lasts long enough for the student to accumulate a total of 300 ECTS credits, so its duration would depend on a number of credits acquired during the bachelor studies. Pre-Bologna magistar programs were abandoned – after earning an M.Sc. degree and satisfying other academic requirements a student could proceed to earn a doctor of science degree directly, or skip M.Sc. if the diplom program lasted more than 3 years as it was possible to do so for some time. == Guyana == In Guyana, all universities, including University of Guyana, Texila American University, American International School of Medicine have Master of Science courses as postgraduate degrees. Students who have completed undergraduate Bachelor of Science degree are eligible to study in this discipline. == India == In India, universities offer M.Sc. programs usually in sciences discipline. Generally, post-graduate scientific courses lead to M.Sc. degree while post-graduate engineering courses lead to ME or MTech degree. For example, a master's in automotive engineering would normally be an ME or MTech, while a master's in physics would be an M.Sc. A few top universities also offer combined undergraduate-postgraduate programs leading to a master's degree which is known as integrated masters. A Master of Science in Engineering (MS.Engg.) degree is also offered in India. It is usually structured as an engineering research degree, lesser than PhD and considered to be parallel to M.Phil. degree in humanities and science. Some institutes such as IITs offer an MS degree for postgraduate engineering courses. This degree is considered a research-oriented degree whereas MTech or ME degree is usually not a research degree in India. M.Sc. degree is also awarded by various IISERs which are one of the top institutes in India. == Iran == In Iran, similar to Canada, Master of Science (MSc) or in Iranian form Kārshenāsi-e arshad degrees may be entirely course-based, entirely research-based, or most commonly a mixture. Master's programs typically take two to three years to complete and the completion of a scientific thesis is often required. == Ireland == Like all EU member states, Ireland follows the Bologna Process. In Ireland, Master of Science (MSc) may be course-based with a research component or entirely research based. The program is most commonly a one-year program and a thesis is required for both course-based and research based degrees. == Israel == In Israel, Master of Science (MSc) may be entirely course-based or include research. The program is most commonly a two-year program and a thesis is required only for research based degrees. == Italy == Like all EU member states, Italy follows the Bologna Process. The degree Master of Science is awarded in the Italian form, Laurea Magistrale. Before the current organization of academic studies there was the Laurea. According to the subject the laurea could require four, five or six years of study. The laurea was subsequently split into a "laurea triennale" (three years) and a "laurea magistrale" (two more years). == Nepal == In Nepal, universities offer the Master of Science degree usually in science and engineering areas. Tribhuvan University offers MSc degree for all the science and engineering courses. Pokhara University and Purbanchal University offer ME for engineering and MSc for science. Kathmandu University offers MS by Research and ME degrees for science and engineering. == Netherlands == Like all EU member states, the Netherlands follows the Bologna Process. In the past graduates of applied universities (HBO) were excluded from using titles such as MSc, as HBO institutions are formally not universities but polytechnic institutions of higher education. However, since 2014 academic titles are granted to any university graduate. However, older academic titles used in the Netherlands are: ingenieur (abbreviated as ir.) (for graduates who followed a technical or agricultural program) meester (abbreviated as mr.) (for graduates who followed an LLM law program) doctorandus (abbreviated as drs.) (in all other cases). The bearers of these titles can use either the older title, of MSc, LL.M or MA but not both for the same field of study. == New Zealand == New Zealand universities commonly have coursework or research-based Master of Science courses for graduate students. They typically run for 2 years full-time, with varying amounts of research involved. == Norway == Norway follows the Bologna Process. For engineering, the Master of Science academic degree has been recently introduced and has replaced the previous award forms "Sivilingeniør" (engineer, a.k.a. engineering master) and "Hovedfag" (academic master). Both were awarded after 5 years of university-level studies and required the completion of a scientific thesis. "Siv.ing", is a protected title traditionally awarded to engineering students who completed a five-year education at The Norwegian University of Science and Technology (Norwegian: Norges teknisk-naturvitenskapelige universitet, NTNU) or other university programs deemed to be equivalent in academic merit. Historically there was no bachelor's degree involved and today's program is a five years master's degree education. The "Siv.ing" title is in the process of being phased out, replaced by (for now, complemented by) the "M.Sc." title. By and large, "Siv.ing" is a title tightly being held on to for the sake of tradition. In academia, the new program offers separate three-year bachelor and two-year master programs. It is awarded in the natural sciences, mathematics and computer science fields. The completion of a scientific thesis is required. All master's degrees are designed to certify a level of education and qualify for a doctorate program. Master of Science in Business is the English title for those taking a higher business degree, "Siviløkonom" in Norwegian. In addition, there is, for example, the 'Master of Business Administration' (MBA), a practically oriented master's degree in business, but with less mathematics and econometrics, due to its less specific entry requirements and smaller focus on research. == Pakistan == Pakistan inherited its conventions pertaining to higher education from United Kingdom after independence in 1947. Master of Science degree is typically abbreviated as M.Sc. (as in the United Kingdom) and which is awarded after 16 years of education (equivalent with a bachelor's degree in the US and many other countries). Recently, in pursuance to some of the reforms by the Higher Education Commission of Pakistan (the regulatory body of higher education in Pakistan), the traditional 2-year Bachelor of Science (B.Sc.) degree has been replaced by the 4-year Bachelor of Science degree, which is abbreviated as B.S. to enable the Pakistani degrees with the rest of the world. Subsequently, students who pass a 4-year B.S. degree that is awarded after 16 years of education are then eligible to apply for M.S. degree, which is considered at par with Master of Philosophy (M.Phil.) degree. == Poland == Like all EU member states, Poland follows the Bologna Process. The Polish equivalent of Master of Science is "magister" (abbreviated "mgr", written pre-nominally much like "Dr"). Starting in 2001, the MSc programs typically lasting 5 years began to be replaced as below: 3-year associates programs, (licentiate degree termed "licencjat" in Polish. No abbreviated pre-nominal or title.) 3.5-year engineer programs (termed "inżynier", utilizing the pre-nominal abbreviation "inż.") 2-year master programs open to both "licencjat" and "inż." graduates. 1.5-year master programs open only to "inż." graduates. The degree is awarded predominantly in the natural sciences, mathematics, computer science, economics, as well as in the arts and other disciplines. Those who graduate from an engineering program prior to being awarded a master's degree are allowed to use the "mgr inż." pre-nominal ("master engineer"). This is most common in engineering and agricultural fields of study. Defense of a research thesis is required. All master's degrees in Poland qualify for a doctorate program. == Russia == The title of "master" was introduced by Alexander I at 24 January 1803. The Master had an intermediate position between the candidate and doctor according to the decree "About colleges structure". The master's degree was abolished from 1917 to 1934. Russia has followed the Bologna Process for higher education in Europe since 2011. == Spain == Like all EU member states, Spain follows the Bologna Process. The Master of Science (MSc) degree is a program officially recognized by the Spanish Ministry of Education. It usually involves 1 or 2 years of full-time study. It is targeted at pre-experience candidates who have recently finished their undergraduate studies. An MSc degree can be awarded in every field of study. An MSc degree is required in order to progress to a PhD. MSci, MPhil and DEA are equivalent in Spain. == Sweden == Like all EU member states, Sweden follows the Bologna Process. The Master of Science academic degree has, like in Germany, recently been introduced in Sweden. Students studying Master of Science in Engineering programs are rewarded both the English Master of Science Degree, but also the Swedish equivalent "Teknologisk masterexamen". Whilst "Civilingenjör" is an at least five year long education. == Syria == The Master of Science is a degree that can be studied only in public universities. The program is usually 2 years, but it can be extended to 3 or 4 years. The student is required to pass a specific bachelor's degree to attend a specific Master of Science degree program. The master of science is mostly a research degree, except for some types of programs held with cooperation of foreign universities. The student typically attends courses in the first year of the program and should then prepare a research thesis. Publishing two research papers is recommended and will increase the final evaluation grade. == United Kingdom == The Master of Science (MSc) is typically a taught postgraduate degree, involving lectures, examinations and a project dissertation (normally taking up a third of the program). Master's programs usually involve a minimum of 1 year of full-time study (180 UK credits, of which 150 must be at master's level) and sometimes up to 2 years of full-time study (or the equivalent period part-time). Taught master's degrees are normally classified into Pass, Merit and Distinction (although some universities do not give Merit). Some universities also offer MSc by research programs, where a longer project or set of projects is undertaken full-time; master's degrees by research are normally pass/fail, although some universities may offer a distinction. The more recent Master in Science (MSci or M.Sci.) degree (Master of Natural Sciences at the University of Cambridge), is an undergraduate (UG) level integrated master's degree offered by UK institutions since the 1990s. It is offered as a first degree with the first three (four in Scotland) years similar to a BSc course and a final year (120 UK credits) at master's level, including a dissertation. The final MSci qualification is thus at the same level as a traditional MSc. == United States == The Master of Science (Magister Scientiæ) degree is normally a full-time two-year degree often abbreviated "MS" or "M.S." It is the primary type in most subjects and may be entirely course-based, entirely research-based or (more typically) a combination of the two. The combination often involves writing and defending a thesis or completing a research project which represents the culmination of the material learned. Admission to a master's program is normally contingent upon holding a bachelor's degree and progressing to a doctoral program may require a master's degree. In some fields or graduate programs, work on a doctorate can begin immediately after the bachelor's degree. Some programs provide for a joint bachelor's and master's degree after about five years. Some universities use the Latin degree names and due to the flexibility of word order in Latin, Artium Magister (A.M.) or Scientiæ Magister (S.M. or Sc.M.) may be used in some institutions. == See also == Master of Science in Accounting Master of Science in Administration Master of Science in Computer Science Master of Science in Corporate Communication Master of Science in Economics Master of Science in Engineering Master of Science in Finance Master of Science in Foreign Service Master of Science in Information Systems Master of Science in Information Technology Master of Science in Management Master of Science in Nursing Master of Science in Occupational Therapy Master of Science in Physician Assistant Studies Master of Science in Project Management Master of Science in Systems Management == References ==
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https://en.wikipedia.org/wiki/Master_of_Science
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Actuarial science is the discipline that applies mathematical and statistical methods to assess risk in insurance, pension, finance, investment and other industries and professions. Actuaries are professionals trained in this discipline. In many countries, actuaries must demonstrate their competence by passing a series of rigorous professional examinations focused in fields such as probability and predictive analysis. Actuarial science includes a number of interrelated subjects, including mathematics, probability theory, statistics, finance, economics, financial accounting and computer science. Historically, actuarial science used deterministic models in the construction of tables and premiums. The science has gone through revolutionary changes since the 1980s due to the proliferation of high speed computers and the union of stochastic actuarial models with modern financial theory. Many universities have undergraduate and graduate degree programs in actuarial science. In 2010, a study published by job search website CareerCast ranked actuary as the #1 job in the United States. The study used five key criteria to rank jobs: environment, income, employment outlook, physical demands, and stress. In 2024, U.S. News & World Report ranked actuary as the third-best job in the business sector and the eighth-best job in STEM. == Subfields == === Life insurance, pensions and healthcare === Actuarial science became a formal mathematical discipline in the late 17th century with the increased demand for long-term insurance coverage such as burial, life insurance, and annuities. These long term coverages required that money be set aside to pay future benefits, such as annuity and death benefits many years into the future. This requires estimating future contingent events, such as the rates of mortality by age, as well as the development of mathematical techniques for discounting the value of funds set aside and invested. This led to the development of an important actuarial concept, referred to as the present value of a future sum. Certain aspects of the actuarial methods for discounting pension funds have come under criticism from modern financial economics. In traditional life insurance, actuarial science focuses on the analysis of mortality, the production of life tables, and the application of compound interest to produce life insurance, annuities and endowment policies. Contemporary life insurance programs have been extended to include credit and mortgage insurance, key person insurance for small businesses, long term care insurance and health savings accounts. In health insurance, including insurance provided directly by employers, and social insurance, actuarial science focuses on the analysis of rates of disability, morbidity, mortality, fertility and other contingencies. The effects of consumer choice and the geographical distribution of the utilization of medical services and procedures, and the utilization of drugs and therapies, is also of great importance. These factors underlay the development of the Resource-Base Relative Value Scale (RBRVS) at Harvard in a multi-disciplined study. Actuarial science also aids in the design of benefit structures, reimbursement standards, and the effects of proposed government standards on the cost of healthcare. In the pension industry, actuarial methods are used to measure the costs of alternative strategies with regard to the design, funding, accounting, administration, and maintenance or redesign of pension plans. The strategies are greatly influenced by short-term and long-term bond rates, the funded status of the pension and benefit arrangements, collective bargaining; the employer's old, new and foreign competitors; the changing demographics of the workforce; changes in the internal revenue code; changes in the attitude of the internal revenue service regarding the calculation of surpluses; and equally importantly, both the short and long term financial and economic trends. It is common with mergers and acquisitions that several pension plans have to be combined or at least administered on an equitable basis. When benefit changes occur, old and new benefit plans have to be blended, satisfying new social demands and various government discrimination test calculations, and providing employees and retirees with understandable choices and transition paths. Benefit plans liabilities have to be properly valued, reflecting both earned benefits for past service, and the benefits for future service. Finally, funding schemes have to be developed that are manageable and satisfy the standards board or regulators of the appropriate country, such as the Financial Accounting Standards Board in the United States. In social welfare programs, the Office of the Chief Actuary (OCACT), Social Security Administration plans and directs a program of actuarial estimates and analyses relating to SSA-administered retirement, survivors and disability insurance programs and to proposed changes in those programs. It evaluates operations of the Federal Old-Age and Survivors Insurance Trust Fund and the Federal Disability Insurance Trust Fund, conducts studies of program financing, performs actuarial and demographic research on social insurance and related program issues involving mortality, morbidity, utilization, retirement, disability, survivorship, marriage, unemployment, poverty, old age, families with children, etc., and projects future workloads. In addition, the Office is charged with conducting cost analyses relating to the Supplemental Security Income (SSI) program, a general-revenue financed, means-tested program for low-income aged, blind and disabled people. The office provides technical and consultative services to the Commissioner, to the board of trustees of the Social Security Trust Funds, and its staff appears before Congressional Committees to provide expert testimony on the actuarial aspects of Social Security issues. === Applications to other forms of insurance === Actuarial science is also applied to property, casualty, liability, and general insurance. In these forms of insurance, coverage is generally provided on a renewable period, (such as a yearly). Coverage can be cancelled at the end of the period by either party. Property and casualty insurance companies tend to specialize because of the complexity and diversity of risks. One division is to organize around personal and commercial lines of insurance. Personal lines of insurance are for individuals and include fire, auto, homeowners, theft and umbrella coverages. Commercial lines address the insurance needs of businesses and include property, business continuation, product liability, fleet/commercial vehicle, workers compensation, fidelity and surety, and D&O insurance. The insurance industry also provides coverage for exposures such as catastrophe, weather-related risks, earthquakes, patent infringement and other forms of corporate espionage, terrorism, and "one-of-a-kind" (e.g., satellite launch). Actuarial science provides data collection, measurement, estimating, forecasting, and valuation tools to provide financial and underwriting data for management to assess marketing opportunities and the nature of the risks. Actuarial science often helps to assess the overall risk from catastrophic events in relation to its underwriting capacity or surplus. In the reinsurance fields, actuarial science can be used to design and price reinsurance and retrocession arrangements, and to establish reserve funds for known claims and future claims and catastrophes. === Actuaries in criminal justice === There is an increasing trend to recognize that actuarial skills can be applied to a range of applications outside the traditional fields of insurance, pensions, etc. One notable example is the use in some US states of actuarial models to set criminal sentencing guidelines. These models attempt to predict the chance of re-offending according to rating factors which include the type of crime, age, educational background and ethnicity of the offender. However, these models have been open to criticism as providing justification for discrimination against specific ethnic groups by law enforcement personnel. Whether this is statistically correct or a self-fulfilling correlation remains under debate. Another example is the use of actuarial models to assess the risk of sex offense recidivism. Actuarial models and associated tables, such as the MnSOST-R, Static-99, and SORAG, have been used since the late 1990s to determine the likelihood that a sex offender will re-offend and thus whether he or she should be institutionalized or set free. === Actuarial science related to modern financial economics === Traditional actuarial science and modern financial economics in the US have different practices, which is caused by different ways of calculating funding and investment strategies, and by different regulations. Regulations are from the Armstrong investigation of 1905, the Glass–Steagall Act of 1932, the adoption of the Mandatory Security Valuation Reserve by the National Association of Insurance Commissioners, which cushioned market fluctuations, and the Financial Accounting Standards Board, (FASB) in the US and Canada, which regulates pensions valuations and funding. == History == Historically, much of the foundation of actuarial theory predated modern financial theory. In the early twentieth century, actuaries were developing many techniques that can be found in modern financial theory, but for various historical reasons, these developments did not achieve much recognition. As a result, actuarial science developed along a different path, becoming more reliant on assumptions, as opposed to the arbitrage-free risk-neutral valuation concepts used in modern finance. The divergence is not related to the use of historical data and statistical projections of liability cash flows, but is instead caused by the manner in which traditional actuarial methods apply market data with those numbers. For example, one traditional actuarial method suggests that changing the asset allocation mix of investments can change the value of liabilities and assets (by changing the discount rate assumption). This concept is inconsistent with financial economics. The potential of modern financial economics theory to complement existing actuarial science was recognized by actuaries in the mid-twentieth century. In the late 1980s and early 1990s, there was a distinct effort for actuaries to combine financial theory and stochastic methods into their established models. Ideas from financial economics became increasingly influential in actuarial thinking, and actuarial science has started to embrace more sophisticated mathematical modelling of finance. Today, the profession, both in practice and in the educational syllabi of many actuarial organizations, is cognizant of the need to reflect the combined approach of tables, loss models, stochastic methods, and financial theory. However, assumption-dependent concepts are still widely used (such as the setting of the discount rate assumption as mentioned earlier), particularly in North America. Product design adds another dimension to the debate. Financial economists argue that pension benefits are bond-like and should not be funded with equity investments without reflecting the risks of not achieving expected returns. But some pension products do reflect the risks of unexpected returns. In some cases, the pension beneficiary assumes the risk, or the employer assumes the risk. The current debate now seems to be focusing on four principles: financial models should be free of arbitrage. assets and liabilities with identical cash flows should have the same price. This is at odds with FASB. the value of an asset is independent of its financing. how pension assets should be invested Essentially, financial economics state that pension assets should not be invested in equities for a variety of theoretical and practical reasons. === Pre-formalisation === Elementary mutual aid agreements and pensions arose in antiquity. Early in the Roman empire, associations were formed to meet the expenses of burial, cremation, and monuments—precursors to burial insurance and friendly societies. A small sum was paid into a communal fund on a weekly basis, and upon the death of a member, the fund would cover the expenses of rites and burial. These societies sometimes sold shares in the building of columbāria, or burial vaults, owned by the fund—the precursor to mutual insurance companies. Other early examples of mutual surety and assurance pacts can be traced back to various forms of fellowship within the Saxon clans of England and their Germanic forebears, and to Celtic society. However, many of these earlier forms of surety and aid would often fail due to lack of understanding and knowledge. === Initial development === The 17th century was a period of advances in mathematics in Germany, France and England. At the same time there was a rapidly growing desire and need to place the valuation of personal risk on a more scientific basis. Independently of each other, compound interest was studied and probability theory emerged as a well-understood mathematical discipline. Another important advance came in 1662 from a London draper, the father of demography, John Graunt, who showed that there were predictable patterns of longevity and death in a group, or cohort, of people of the same age, despite the uncertainty of the date of death of any one individual. This study became the basis for the original life table. One could now set up an insurance scheme to provide life insurance or pensions for a group of people, and to calculate with some degree of accuracy how much each person in the group should contribute to a common fund assumed to earn a fixed rate of interest. The first person to demonstrate publicly how this could be done was Edmond Halley (of Halley's comet fame). Halley constructed his own life table, and showed how it could be used to calculate the premium amount someone of a given age should pay to purchase a life annuity. === Early actuaries === James Dodson's pioneering work on the long term insurance contracts under which the same premium is charged each year led to the formation of the Society for Equitable Assurances on Lives and Survivorship (now commonly known as Equitable Life) in London in 1762. William Morgan is often considered the father of modern actuarial science for his work in the field in the 1780s and 90s. Many other life insurance companies and pension funds were created over the following 200 years. Equitable Life was the first to use the word "actuary" for its chief executive officer in 1762. Previously, "actuary" meant an official who recorded the decisions, or "acts", of ecclesiastical courts. Other companies that did not use such mathematical and scientific methods most often failed or were forced to adopt the methods pioneered by Equitable. === Technological advances === In the 18th and 19th centuries, calculations were performed without computers. The computations of life insurance premiums and reserving requirements are rather complex, and actuaries developed techniques to make the calculations as easy as possible, for example "commutation functions" (essentially precalculated columns of summations over time of discounted values of survival and death probabilities). Actuarial organizations were founded to support and further both actuaries and actuarial science, and to protect the public interest by promoting competency and ethical standards. However, calculations remained cumbersome, and actuarial shortcuts were commonplace. Non-life actuaries followed in the footsteps of their life insurance colleagues during the 20th century. The 1920 revision for the New-York based National Council on Workmen's Compensation Insurance rates took over two months of around-the-clock work by day and night teams of actuaries. In the 1930s and 1940s, the mathematical foundations for stochastic processes were developed. Actuaries could now begin to estimate losses using models of random events, instead of the deterministic methods they had used in the past. The introduction and development of the computer further revolutionized the actuarial profession. From pencil-and-paper to punchcards to current high-speed devices, the modeling and forecasting ability of the actuary has rapidly improved, while still being heavily dependent on the assumptions input into the models, and actuaries needed to adjust to this new world . == See also == == References == === Works cited === === Bibliography === Charles L. Trowbridge (1989). "Fundamental Concepts of Actuarial Science" (PDF). Revised Edition. Actuarial Education and Research Fund. Archived from the original (PDF) on 2006-06-29. Retrieved 2006-06-28. == External links ==
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https://en.wikipedia.org/wiki/Actuarial_science
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In programming language theory and type theory, polymorphism is the use of one symbol to represent multiple different types. In object-oriented programming, polymorphism is the provision of one interface to entities of different data types. The concept is borrowed from a principle in biology where an organism or species can have many different forms or stages. The most commonly recognized major forms of polymorphism are: Ad hoc polymorphism: defines a common interface for an arbitrary set of individually specified types. Parametric polymorphism: not specifying concrete types and instead use abstract symbols that can substitute for any type. Subtyping (also called subtype polymorphism or inclusion polymorphism): when a name denotes instances of many different classes related by some common superclass. == History == Interest in polymorphic type systems developed significantly in the 1990s, with practical implementations beginning to appear by the end of the decade. Ad hoc polymorphism and parametric polymorphism were originally described in Christopher Strachey's Fundamental Concepts in Programming Languages, where they are listed as "the two main classes" of polymorphism. Ad hoc polymorphism was a feature of ALGOL 68, while parametric polymorphism was the core feature of ML's type system. In a 1985 paper, Peter Wegner and Luca Cardelli introduced the term inclusion polymorphism to model subtypes and inheritance, citing Simula as the first programming language to implement it. == Forms == === Ad hoc polymorphism === Christopher Strachey chose the term ad hoc polymorphism to refer to polymorphic functions that can be applied to arguments of different types, but that behave differently depending on the type of the argument to which they are applied (also known as function overloading or operator overloading). The term "ad hoc" in this context is not pejorative: instead, it means that this form of polymorphism is not a fundamental feature of the type system. In the Java example below, the add functions seem to work generically over two types (integer and string) when looking at the invocations, but are considered to be two entirely distinct functions by the compiler for all intents and purposes: In dynamically typed languages the situation can be more complex as the correct function that needs to be invoked might only be determinable at run time. Implicit type conversion has also been defined as a form of polymorphism, referred to as "coercion polymorphism". === Parametric polymorphism === Parametric polymorphism allows a function or a data type to be written generically, so that it can handle values uniformly without depending on their type. Parametric polymorphism is a way to make a language more expressive while still maintaining full static type safety. The concept of parametric polymorphism applies to both data types and functions. A function that can evaluate to or be applied to values of different types is known as a polymorphic function. A data type that can appear to be of a generalized type (e.g., a list with elements of arbitrary type) is designated polymorphic data type like the generalized type from which such specializations are made. Parametric polymorphism is ubiquitous in functional programming, where it is often simply referred to as "polymorphism". The next example in Haskell shows a parameterized list data type and two parametrically polymorphic functions on them: Parametric polymorphism is also available in several object-oriented languages. For instance, templates in C++ and D, or under the name generics in C#, Delphi, Java, and Go: John C. Reynolds (and later Jean-Yves Girard) formally developed this notion of polymorphism as an extension to lambda calculus (called the polymorphic lambda calculus or System F). Any parametrically polymorphic function is necessarily restricted in what it can do, working on the shape of the data instead of its value, leading to the concept of parametricity. === Subtyping === Some languages employ the idea of subtyping (also called subtype polymorphism or inclusion polymorphism) to restrict the range of types that can be used in a particular case of polymorphism. In these languages, subtyping allows a function to be written to take an object of a certain type T, but also work correctly, if passed an object that belongs to a type S that is a subtype of T (according to the Liskov substitution principle). This type relation is sometimes written S <: T. Conversely, T is said to be a supertype of S, written T :> S. Subtype polymorphism is usually resolved dynamically (see below). In the following Java example cats and dogs are made subtypes of pets. The procedure letsHear() accepts a pet, but will also work correctly if a subtype is passed to it: In another example, if Number, Rational, and Integer are types such that Number :> Rational and Number :> Integer (Rational and Integer as subtypes of a type Number that is a supertype of them), a function written to take a Number will work equally well when passed an Integer or Rational as when passed a Number. The actual type of the object can be hidden from clients into a black box, and accessed via object identity. If the Number type is abstract, it may not even be possible to get your hands on an object whose most-derived type is Number (see abstract data type, abstract class). This particular kind of type hierarchy is known, especially in the context of the Scheme language, as a numerical tower, and usually contains many more types. Object-oriented programming languages offer subtype polymorphism using subclassing (also known as inheritance). In typical implementations, each class contains what is called a virtual table (shortly called vtable) — a table of functions that implement the polymorphic part of the class interface—and each object contains a pointer to the vtable of its class, which is then consulted whenever a polymorphic method is called. This mechanism is an example of: late binding, because virtual function calls are not bound until the time of invocation; single dispatch (i.e., single-argument polymorphism), because virtual function calls are bound simply by looking through the vtable provided by the first argument (the this object), so the runtime types of the other arguments are completely irrelevant. The same goes for most other popular object systems. Some, however, such as Common Lisp Object System, provide multiple dispatch, under which method calls are polymorphic in all arguments. The interaction between parametric polymorphism and subtyping leads to the concepts of variance and bounded quantification. === Row polymorphism === Row polymorphism is a similar, but distinct concept from subtyping. It deals with structural types. It allows the usage of all values whose types have certain properties, without losing the remaining type information. === Polytypism === A related concept is polytypism (or data type genericity). A polytypic function is more general than polymorphic, and in such a function, "though one can provide fixed ad hoc cases for specific data types, an ad hoc combinator is absent". === Rank polymorphism === Rank polymorphism is one of the defining features of the array programming languages, like APL. The essence of the rank-polymorphic programming model is implicitly treating all operations as aggregate operations, usable on arrays with arbitrarily many dimensions, which is to say that rank polymorphism allows functions to be defined to operate on arrays of any shape and size. == Implementation aspects == === Static and dynamic polymorphism === Polymorphism can be distinguished by when the implementation is selected: statically (at compile time) or dynamically (at run time, typically via a virtual function). This is known respectively as static dispatch and dynamic dispatch, and the corresponding forms of polymorphism are accordingly called static polymorphism and dynamic polymorphism. Static polymorphism executes faster, because there is no dynamic dispatch overhead, but requires additional compiler support. Further, static polymorphism allows greater static analysis by compilers (notably for optimization), source code analysis tools, and human readers (programmers). Dynamic polymorphism is more flexible but slower—for example, dynamic polymorphism allows duck typing, and a dynamically linked library may operate on objects without knowing their full type. Static polymorphism typically occurs in ad hoc polymorphism and parametric polymorphism, whereas dynamic polymorphism is usual for subtype polymorphism. However, it is possible to achieve static polymorphism with subtyping through more sophisticated use of template metaprogramming, namely the curiously recurring template pattern. When polymorphism is exposed via a library, static polymorphism becomes impossible for dynamic libraries as there is no way of knowing what types the parameters are when the shared object is built. While languages like C++ and Rust use monomorphized templates, the Swift programming language makes extensive use of dynamic dispatch to build the application binary interface for these libraries by default. As a result, more code can be shared for a reduced system size at the cost of runtime overhead. == See also == Type class Virtual inheritance == References == == External links == C++ examples of polymorphism Objects and Polymorphism (Visual Prolog) Polymorphism on MSDN Polymorphism Java Documentation on Oracle
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Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid–liquid interfaces, solid–gas interfaces, solid–vacuum interfaces, and liquid–gas interfaces. It includes the fields of surface chemistry and surface physics. Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis, semiconductor device fabrication, fuel cells, self-assembled monolayers, and adhesives. Surface science is closely related to interface and colloid science. Interfacial chemistry and physics are common subjects for both. The methods are different. In addition, interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces. == History == The field of surface chemistry started with heterogeneous catalysis pioneered by Paul Sabatier on hydrogenation and Fritz Haber on the Haber process. Irving Langmuir was also one of the founders of this field, and the scientific journal on surface science, Langmuir, bears his name. The Langmuir adsorption equation is used to model monolayer adsorption where all surface adsorption sites have the same affinity for the adsorbing species and do not interact with each other. Gerhard Ertl in 1974 described for the first time the adsorption of hydrogen on a palladium surface using a novel technique called LEED. Similar studies with platinum, nickel, and iron followed. Most recent developments in surface sciences include the 2007 Nobel prize of Chemistry winner Gerhard Ertl's advancements in surface chemistry, specifically his investigation of the interaction between carbon monoxide molecules and platinum surfaces. == Chemistry == Surface chemistry can be roughly defined as the study of chemical reactions at interfaces. It is closely related to surface engineering, which aims at modifying the chemical composition of a surface by incorporation of selected elements or functional groups that produce various desired effects or improvements in the properties of the surface or interface. Surface science is of particular importance to the fields of heterogeneous catalysis, electrochemistry, and geochemistry. === Catalysis === The adhesion of gas or liquid molecules to the surface is known as adsorption. This can be due to either chemisorption or physisorption, and the strength of molecular adsorption to a catalyst surface is critically important to the catalyst's performance (see Sabatier principle). However, it is difficult to study these phenomena in real catalyst particles, which have complex structures. Instead, well-defined single crystal surfaces of catalytically active materials such as platinum are often used as model catalysts. Multi-component materials systems are used to study interactions between catalytically active metal particles and supporting oxides; these are produced by growing ultra-thin films or particles on a single crystal surface. Relationships between the composition, structure, and chemical behavior of these surfaces are studied using ultra-high vacuum techniques, including adsorption and temperature-programmed desorption of molecules, scanning tunneling microscopy, low energy electron diffraction, and Auger electron spectroscopy. Results can be fed into chemical models or used toward the rational design of new catalysts. Reaction mechanisms can also be clarified due to the atomic-scale precision of surface science measurements. === Electrochemistry === Electrochemistry is the study of processes driven through an applied potential at a solid–liquid or liquid–liquid interface. The behavior of an electrode–electrolyte interface is affected by the distribution of ions in the liquid phase next to the interface forming the electrical double layer. Adsorption and desorption events can be studied at atomically flat single-crystal surfaces as a function of applied potential, time and solution conditions using spectroscopy, scanning probe microscopy and surface X-ray scattering. These studies link traditional electrochemical techniques such as cyclic voltammetry to direct observations of interfacial processes. === Geochemistry === Geological phenomena such as iron cycling and soil contamination are controlled by the interfaces between minerals and their environment. The atomic-scale structure and chemical properties of mineral–solution interfaces are studied using in situ synchrotron X-ray techniques such as X-ray reflectivity, X-ray standing waves, and X-ray absorption spectroscopy as well as scanning probe microscopy. For example, studies of heavy metal or actinide adsorption onto mineral surfaces reveal molecular-scale details of adsorption, enabling more accurate predictions of how these contaminants travel through soils or disrupt natural dissolution–precipitation cycles. == Physics == Surface physics can be roughly defined as the study of physical interactions that occur at interfaces. It overlaps with surface chemistry. Some of the topics investigated in surface physics include friction, surface states, surface diffusion, surface reconstruction, surface phonons and plasmons, epitaxy, the emission and tunneling of electrons, spintronics, and the self-assembly of nanostructures on surfaces. Techniques to investigate processes at surfaces include surface X-ray scattering, scanning probe microscopy, surface-enhanced Raman spectroscopy and X-ray photoelectron spectroscopy. == Analysis techniques == The study and analysis of surfaces involves both physical and chemical analysis techniques. Several modern methods probe the topmost 1–10 nm of surfaces exposed to vacuum. These include angle-resolved photoemission spectroscopy (ARPES), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), electron energy loss spectroscopy (EELS), thermal desorption spectroscopy (TPD), ion scattering spectroscopy (ISS), secondary ion mass spectrometry, dual-polarization interferometry, and other surface analysis methods included in the list of materials analysis methods. Many of these techniques require vacuum as they rely on the detection of electrons or ions emitted from the surface under study. Moreover, in general ultra-high vacuum, in the range of 10−7 pascal pressure or better, it is necessary to reduce surface contamination by residual gas, by reducing the number of molecules reaching the sample over a given time period. At 0.1 mPa (10−6 torr) partial pressure of a contaminant and standard temperature, it only takes on the order of 1 second to cover a surface with a one-to-one monolayer of contaminant to surface atoms, so much lower pressures are needed for measurements. This is found by an order of magnitude estimate for the (number) specific surface area of materials and the impingement rate formula from the kinetic theory of gases. Purely optical techniques can be used to study interfaces under a wide variety of conditions. Reflection-absorption infrared, dual polarisation interferometry, surface-enhanced Raman spectroscopy and sum frequency generation spectroscopy can be used to probe solid–vacuum as well as solid–gas, solid–liquid, and liquid–gas surfaces. Multi-parametric surface plasmon resonance works in solid–gas, solid–liquid, liquid–gas surfaces and can detect even sub-nanometer layers. It probes the interaction kinetics as well as dynamic structural changes such as liposome collapse or swelling of layers in different pH. Dual-polarization interferometry is used to quantify the order and disruption in birefringent thin films. This has been used, for example, to study the formation of lipid bilayers and their interaction with membrane proteins. Acoustic techniques, such as quartz crystal microbalance with dissipation monitoring, is used for time-resolved measurements of solid–vacuum, solid–gas and solid–liquid interfaces. The method allows for analysis of molecule–surface interactions as well as structural changes and viscoelastic properties of the adlayer. X-ray scattering and spectroscopy techniques are also used to characterize surfaces and interfaces. While some of these measurements can be performed using laboratory X-ray sources, many require the high intensity and energy tunability of synchrotron radiation. X-ray crystal truncation rods (CTR) and X-ray standing wave (XSW) measurements probe changes in surface and adsorbate structures with sub-Ångström resolution. Surface-extended X-ray absorption fine structure (SEXAFS) measurements reveal the coordination structure and chemical state of adsorbates. Grazing-incidence small angle X-ray scattering (GISAXS) yields the size, shape, and orientation of nanoparticles on surfaces. The crystal structure and texture of thin films can be investigated using grazing-incidence X-ray diffraction (GIXD, GIXRD). X-ray photoelectron spectroscopy (XPS) is a standard tool for measuring the chemical states of surface species and for detecting the presence of surface contamination. Surface sensitivity is achieved by detecting photoelectrons with kinetic energies of about 10–1000 eV, which have corresponding inelastic mean free paths of only a few nanometers. This technique has been extended to operate at near-ambient pressures (ambient pressure XPS, AP-XPS) to probe more realistic gas–solid and liquid–solid interfaces. Performing XPS with hard X-rays at synchrotron light sources yields photoelectrons with kinetic energies of several keV (hard X-ray photoelectron spectroscopy, HAXPES), enabling access to chemical information from buried interfaces. Modern physical analysis methods include scanning-tunneling microscopy (STM) and a family of methods descended from it, including atomic force microscopy (AFM). These microscopies have considerably increased the ability of surface scientists to measure the physical structure of many surfaces. For example, they make it possible to follow reactions at the solid–gas interface in real space, if those proceed on a time scale accessible by the instrument. == See also == == References == == Further reading == Kolasinski, Kurt W. (2012-04-30). Surface Science: Foundations of Catalysis and Nanoscience (3 ed.). Wiley. ISBN 978-1119990352. Attard, Gary; Barnes, Colin (January 1998). Surfaces. Oxford Chemistry Primers. ISBN 978-0198556862. == External links == "Ram Rao Materials and Surface Science", a video from the Vega Science Trust Surface Chemistry Discoveries Surface Metrology Guide
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Computer science is the study of computation, information, and automation. Computer science spans theoretical disciplines (such as algorithms, theory of computation, and information theory) to applied disciplines (including the design and implementation of hardware and software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of repositories of data. Human–computer interaction investigates the interfaces through which humans and computers interact, and software engineering focuses on the design and principles behind developing software. Areas such as operating systems, networks and embedded systems investigate the principles and design behind complex systems. Computer architecture describes the construction of computer components and computer-operated equipment. Artificial intelligence and machine learning aim to synthesize goal-orientated processes such as problem-solving, decision-making, environmental adaptation, planning and learning found in humans and animals. Within artificial intelligence, computer vision aims to understand and process image and video data, while natural language processing aims to understand and process textual and linguistic data. The fundamental concern of computer science is determining what can and cannot be automated. The Turing Award is generally recognized as the highest distinction in computer science. == History == The earliest foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks such as the abacus have existed since antiquity, aiding in computations such as multiplication and division. Algorithms for performing computations have existed since antiquity, even before the development of sophisticated computing equipment. Wilhelm Schickard designed and constructed the first working mechanical calculator in 1623. In 1673, Gottfried Leibniz demonstrated a digital mechanical calculator, called the Stepped Reckoner. Leibniz may be considered the first computer scientist and information theorist, because of various reasons, including the fact that he documented the binary number system. In 1820, Thomas de Colmar launched the mechanical calculator industry when he invented his simplified arithmometer, the first calculating machine strong enough and reliable enough to be used daily in an office environment. Charles Babbage started the design of the first automatic mechanical calculator, his Difference Engine, in 1822, which eventually gave him the idea of the first programmable mechanical calculator, his Analytical Engine. He started developing this machine in 1834, and "in less than two years, he had sketched out many of the salient features of the modern computer". "A crucial step was the adoption of a punched card system derived from the Jacquard loom" making it infinitely programmable. In 1843, during the translation of a French article on the Analytical Engine, Ada Lovelace wrote, in one of the many notes she included, an algorithm to compute the Bernoulli numbers, which is considered to be the first published algorithm ever specifically tailored for implementation on a computer. Around 1885, Herman Hollerith invented the tabulator, which used punched cards to process statistical information; eventually his company became part of IBM. Following Babbage, although unaware of his earlier work, Percy Ludgate in 1909 published the 2nd of the only two designs for mechanical analytical engines in history. In 1914, the Spanish engineer Leonardo Torres Quevedo published his Essays on Automatics, and designed, inspired by Babbage, a theoretical electromechanical calculating machine which was to be controlled by a read-only program. The paper also introduced the idea of floating-point arithmetic. In 1920, to celebrate the 100th anniversary of the invention of the arithmometer, Torres presented in Paris the Electromechanical Arithmometer, a prototype that demonstrated the feasibility of an electromechanical analytical engine, on which commands could be typed and the results printed automatically. In 1937, one hundred years after Babbage's impossible dream, Howard Aiken convinced IBM, which was making all kinds of punched card equipment and was also in the calculator business to develop his giant programmable calculator, the ASCC/Harvard Mark I, based on Babbage's Analytical Engine, which itself used cards and a central computing unit. When the machine was finished, some hailed it as "Babbage's dream come true". During the 1940s, with the development of new and more powerful computing machines such as the Atanasoff–Berry computer and ENIAC, the term computer came to refer to the machines rather than their human predecessors. As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. In 1945, IBM founded the Watson Scientific Computing Laboratory at Columbia University in New York City. The renovated fraternity house on Manhattan's West Side was IBM's first laboratory devoted to pure science. The lab is the forerunner of IBM's Research Division, which today operates research facilities around the world. Ultimately, the close relationship between IBM and Columbia University was instrumental in the emergence of a new scientific discipline, with Columbia offering one of the first academic-credit courses in computer science in 1946. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s. The world's first computer science degree program, the Cambridge Diploma in Computer Science, began at the University of Cambridge Computer Laboratory in 1953. The first computer science department in the United States was formed at Purdue University in 1962. Since practical computers became available, many applications of computing have become distinct areas of study in their own rights. == Etymology and scope == Although first proposed in 1956, the term "computer science" appears in a 1959 article in Communications of the ACM, in which Louis Fein argues for the creation of a Graduate School in Computer Sciences analogous to the creation of Harvard Business School in 1921. Louis justifies the name by arguing that, like management science, the subject is applied and interdisciplinary in nature, while having the characteristics typical of an academic discipline. His efforts, and those of others such as numerical analyst George Forsythe, were rewarded: universities went on to create such departments, starting with Purdue in 1962. Despite its name, a significant amount of computer science does not involve the study of computers themselves. Because of this, several alternative names have been proposed. Certain departments of major universities prefer the term computing science, to emphasize precisely that difference. Danish scientist Peter Naur suggested the term datalogy, to reflect the fact that the scientific discipline revolves around data and data treatment, while not necessarily involving computers. The first scientific institution to use the term was the Department of Datalogy at the University of Copenhagen, founded in 1969, with Peter Naur being the first professor in datalogy. The term is used mainly in the Scandinavian countries. An alternative term, also proposed by Naur, is data science; this is now used for a multi-disciplinary field of data analysis, including statistics and databases. In the early days of computing, a number of terms for the practitioners of the field of computing were suggested (albeit facetiously) in the Communications of the ACM—turingineer, turologist, flow-charts-man, applied meta-mathematician, and applied epistemologist. Three months later in the same journal, comptologist was suggested, followed next year by hypologist. The term computics has also been suggested. In Europe, terms derived from contracted translations of the expression "automatic information" (e.g. "informazione automatica" in Italian) or "information and mathematics" are often used, e.g. informatique (French), Informatik (German), informatica (Italian, Dutch), informática (Spanish, Portuguese), informatika (Slavic languages and Hungarian) or pliroforiki (πληροφορική, which means informatics) in Greek. Similar words have also been adopted in the UK (as in the School of Informatics, University of Edinburgh). "In the U.S., however, informatics is linked with applied computing, or computing in the context of another domain." A folkloric quotation, often attributed to—but almost certainly not first formulated by—Edsger Dijkstra, states that "computer science is no more about computers than astronomy is about telescopes." The design and deployment of computers and computer systems is generally considered the province of disciplines other than computer science. For example, the study of computer hardware is usually considered part of computer engineering, while the study of commercial computer systems and their deployment is often called information technology or information systems. However, there has been exchange of ideas between the various computer-related disciplines. Computer science research also often intersects other disciplines, such as cognitive science, linguistics, mathematics, physics, biology, Earth science, statistics, philosophy, and logic. Computer science is considered by some to have a much closer relationship with mathematics than many scientific disciplines, with some observers saying that computing is a mathematical science. Early computer science was strongly influenced by the work of mathematicians such as Kurt Gödel, Alan Turing, John von Neumann, Rózsa Péter and Alonzo Church and there continues to be a useful interchange of ideas between the two fields in areas such as mathematical logic, category theory, domain theory, and algebra. The relationship between computer science and software engineering is a contentious issue, which is further muddied by disputes over what the term "software engineering" means, and how computer science is defined. David Parnas, taking a cue from the relationship between other engineering and science disciplines, has claimed that the principal focus of computer science is studying the properties of computation in general, while the principal focus of software engineering is the design of specific computations to achieve practical goals, making the two separate but complementary disciplines. The academic, political, and funding aspects of computer science tend to depend on whether a department is formed with a mathematical emphasis or with an engineering emphasis. Computer science departments with a mathematics emphasis and with a numerical orientation consider alignment with computational science. Both types of departments tend to make efforts to bridge the field educationally if not across all research. == Philosophy == === Epistemology of computer science === Despite the word science in its name, there is debate over whether or not computer science is a discipline of science, mathematics, or engineering. Allen Newell and Herbert A. Simon argued in 1975, Computer science is an empirical discipline. We would have called it an experimental science, but like astronomy, economics, and geology, some of its unique forms of observation and experience do not fit a narrow stereotype of the experimental method. Nonetheless, they are experiments. Each new machine that is built is an experiment. Actually constructing the machine poses a question to nature; and we listen for the answer by observing the machine in operation and analyzing it by all analytical and measurement means available. It has since been argued that computer science can be classified as an empirical science since it makes use of empirical testing to evaluate the correctness of programs, but a problem remains in defining the laws and theorems of computer science (if any exist) and defining the nature of experiments in computer science. Proponents of classifying computer science as an engineering discipline argue that the reliability of computational systems is investigated in the same way as bridges in civil engineering and airplanes in aerospace engineering. They also argue that while empirical sciences observe what presently exists, computer science observes what is possible to exist and while scientists discover laws from observation, no proper laws have been found in computer science and it is instead concerned with creating phenomena. Proponents of classifying computer science as a mathematical discipline argue that computer programs are physical realizations of mathematical entities and programs that can be deductively reasoned through mathematical formal methods. Computer scientists Edsger W. Dijkstra and Tony Hoare regard instructions for computer programs as mathematical sentences and interpret formal semantics for programming languages as mathematical axiomatic systems. === Paradigms of computer science === A number of computer scientists have argued for the distinction of three separate paradigms in computer science. Peter Wegner argued that those paradigms are science, technology, and mathematics. Peter Denning's working group argued that they are theory, abstraction (modeling), and design. Amnon H. Eden described them as the "rationalist paradigm" (which treats computer science as a branch of mathematics, which is prevalent in theoretical computer science, and mainly employs deductive reasoning), the "technocratic paradigm" (which might be found in engineering approaches, most prominently in software engineering), and the "scientific paradigm" (which approaches computer-related artifacts from the empirical perspective of natural sciences, identifiable in some branches of artificial intelligence). Computer science focuses on methods involved in design, specification, programming, verification, implementation and testing of human-made computing systems. == Fields == As a discipline, computer science spans a range of topics from theoretical studies of algorithms and the limits of computation to the practical issues of implementing computing systems in hardware and software. CSAB, formerly called Computing Sciences Accreditation Board—which is made up of representatives of the Association for Computing Machinery (ACM), and the IEEE Computer Society (IEEE CS)—identifies four areas that it considers crucial to the discipline of computer science: theory of computation, algorithms and data structures, programming methodology and languages, and computer elements and architecture. In addition to these four areas, CSAB also identifies fields such as software engineering, artificial intelligence, computer networking and communication, database systems, parallel computation, distributed computation, human–computer interaction, computer graphics, operating systems, and numerical and symbolic computation as being important areas of computer science. === Theoretical computer science === Theoretical computer science is mathematical and abstract in spirit, but it derives its motivation from practical and everyday computation. It aims to understand the nature of computation and, as a consequence of this understanding, provide more efficient methodologies. ==== Theory of computation ==== According to Peter Denning, the fundamental question underlying computer science is, "What can be automated?" Theory of computation is focused on answering fundamental questions about what can be computed and what amount of resources are required to perform those computations. In an effort to answer the first question, computability theory examines which computational problems are solvable on various theoretical models of computation. The second question is addressed by computational complexity theory, which studies the time and space costs associated with different approaches to solving a multitude of computational problems. The famous P = NP? problem, one of the Millennium Prize Problems, is an open problem in the theory of computation. ==== Information and coding theory ==== Information theory, closely related to probability and statistics, is related to the quantification of information. This was developed by Claude Shannon to find fundamental limits on signal processing operations such as compressing data and on reliably storing and communicating data. Coding theory is the study of the properties of codes (systems for converting information from one form to another) and their fitness for a specific application. Codes are used for data compression, cryptography, error detection and correction, and more recently also for network coding. Codes are studied for the purpose of designing efficient and reliable data transmission methods. ==== Data structures and algorithms ==== Data structures and algorithms are the studies of commonly used computational methods and their computational efficiency. ==== Programming language theory and formal methods ==== Programming language theory is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of programming languages and their individual features. It falls within the discipline of computer science, both depending on and affecting mathematics, software engineering, and linguistics. It is an active research area, with numerous dedicated academic journals. Formal methods are a particular kind of mathematically based technique for the specification, development and verification of software and hardware systems. The use of formal methods for software and hardware design is motivated by the expectation that, as in other engineering disciplines, performing appropriate mathematical analysis can contribute to the reliability and robustness of a design. They form an important theoretical underpinning for software engineering, especially where safety or security is involved. Formal methods are a useful adjunct to software testing since they help avoid errors and can also give a framework for testing. For industrial use, tool support is required. However, the high cost of using formal methods means that they are usually only used in the development of high-integrity and life-critical systems, where safety or security is of utmost importance. Formal methods are best described as the application of a fairly broad variety of theoretical computer science fundamentals, in particular logic calculi, formal languages, automata theory, and program semantics, but also type systems and algebraic data types to problems in software and hardware specification and verification. === Applied computer science === ==== Computer graphics and visualization ==== Computer graphics is the study of digital visual contents and involves the synthesis and manipulation of image data. The study is connected to many other fields in computer science, including computer vision, image processing, and computational geometry, and is heavily applied in the fields of special effects and video games. ==== Image and sound processing ==== Information can take the form of images, sound, video or other multimedia. Bits of information can be streamed via signals. Its processing is the central notion of informatics, the European view on computing, which studies information processing algorithms independently of the type of information carrier – whether it is electrical, mechanical or biological. This field plays important role in information theory, telecommunications, information engineering and has applications in medical image computing and speech synthesis, among others. What is the lower bound on the complexity of fast Fourier transform algorithms? is one of the unsolved problems in theoretical computer science. ==== Computational science, finance and engineering ==== Scientific computing (or computational science) is the field of study concerned with constructing mathematical models and quantitative analysis techniques and using computers to analyze and solve scientific problems. A major usage of scientific computing is simulation of various processes, including computational fluid dynamics, physical, electrical, and electronic systems and circuits, as well as societies and social situations (notably war games) along with their habitats, among many others. Modern computers enable optimization of such designs as complete aircraft. Notable in electrical and electronic circuit design are SPICE, as well as software for physical realization of new (or modified) designs. The latter includes essential design software for integrated circuits. ==== Human–computer interaction ==== Human–computer interaction (HCI) is the field of study and research concerned with the design and use of computer systems, mainly based on the analysis of the interaction between humans and computer interfaces. HCI has several subfields that focus on the relationship between emotions, social behavior and brain activity with computers. ==== Software engineering ==== Software engineering is the study of designing, implementing, and modifying the software in order to ensure it is of high quality, affordable, maintainable, and fast to build. It is a systematic approach to software design, involving the application of engineering practices to software. Software engineering deals with the organizing and analyzing of software—it does not just deal with the creation or manufacture of new software, but its internal arrangement and maintenance. For example software testing, systems engineering, technical debt and software development processes. ==== Artificial intelligence ==== Artificial intelligence (AI) aims to or is required to synthesize goal-orientated processes such as problem-solving, decision-making, environmental adaptation, learning, and communication found in humans and animals. From its origins in cybernetics and in the Dartmouth Conference (1956), artificial intelligence research has been necessarily cross-disciplinary, drawing on areas of expertise such as applied mathematics, symbolic logic, semiotics, electrical engineering, philosophy of mind, neurophysiology, and social intelligence. AI is associated in the popular mind with robotic development, but the main field of practical application has been as an embedded component in areas of software development, which require computational understanding. The starting point in the late 1940s was Alan Turing's question "Can computers think?", and the question remains effectively unanswered, although the Turing test is still used to assess computer output on the scale of human intelligence. But the automation of evaluative and predictive tasks has been increasingly successful as a substitute for human monitoring and intervention in domains of computer application involving complex real-world data. === Computer systems === ==== Computer architecture and microarchitecture ==== Computer architecture, or digital computer organization, is the conceptual design and fundamental operational structure of a computer system. It focuses largely on the way by which the central processing unit performs internally and accesses addresses in memory. Computer engineers study computational logic and design of computer hardware, from individual processor components, microcontrollers, personal computers to supercomputers and embedded systems. The term "architecture" in computer literature can be traced to the work of Lyle R. Johnson and Frederick P. Brooks Jr., members of the Machine Organization department in IBM's main research center in 1959. ==== Concurrent, parallel and distributed computing ==== Concurrency is a property of systems in which several computations are executing simultaneously, and potentially interacting with each other. A number of mathematical models have been developed for general concurrent computation including Petri nets, process calculi and the parallel random access machine model. When multiple computers are connected in a network while using concurrency, this is known as a distributed system. Computers within that distributed system have their own private memory, and information can be exchanged to achieve common goals. ==== Computer networks ==== This branch of computer science aims to manage networks between computers worldwide. ==== Computer security and cryptography ==== Computer security is a branch of computer technology with the objective of protecting information from unauthorized access, disruption, or modification while maintaining the accessibility and usability of the system for its intended users. Historical cryptography is the art of writing and deciphering secret messages. Modern cryptography is the scientific study of problems relating to distributed computations that can be attacked. Technologies studied in modern cryptography include symmetric and asymmetric encryption, digital signatures, cryptographic hash functions, key-agreement protocols, blockchain, zero-knowledge proofs, and garbled circuits. ==== Databases and data mining ==== A database is intended to organize, store, and retrieve large amounts of data easily. Digital databases are managed using database management systems to store, create, maintain, and search data, through database models and query languages. Data mining is a process of discovering patterns in large data sets. == Discoveries == The philosopher of computing Bill Rapaport noted three Great Insights of Computer Science: Gottfried Wilhelm Leibniz's, George Boole's, Alan Turing's, Claude Shannon's, and Samuel Morse's insight: there are only two objects that a computer has to deal with in order to represent "anything". All the information about any computable problem can be represented using only 0 and 1 (or any other bistable pair that can flip-flop between two easily distinguishable states, such as "on/off", "magnetized/de-magnetized", "high-voltage/low-voltage", etc.). Alan Turing's insight: there are only five actions that a computer has to perform in order to do "anything". Every algorithm can be expressed in a language for a computer consisting of only five basic instructions: move left one location; move right one location; read symbol at current location; print 0 at current location; print 1 at current location. Corrado Böhm and Giuseppe Jacopini's insight: there are only three ways of combining these actions (into more complex ones) that are needed in order for a computer to do "anything". Only three rules are needed to combine any set of basic instructions into more complex ones: sequence: first do this, then do that; selection: IF such-and-such is the case, THEN do this, ELSE do that; repetition: WHILE such-and-such is the case, DO this. The three rules of Boehm's and Jacopini's insight can be further simplified with the use of goto (which means it is more elementary than structured programming). == Programming paradigms == Programming languages can be used to accomplish different tasks in different ways. Common programming paradigms include: Functional programming, a style of building the structure and elements of computer programs that treats computation as the evaluation of mathematical functions and avoids state and mutable data. It is a declarative programming paradigm, which means programming is done with expressions or declarations instead of statements. Imperative programming, a programming paradigm that uses statements that change a program's state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of commands for the computer to perform. Imperative programming focuses on describing how a program operates. Object-oriented programming, a programming paradigm based on the concept of "objects", which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods. A feature of objects is that an object's procedures can access and often modify the data fields of the object with which they are associated. Thus object-oriented computer programs are made out of objects that interact with one another. Service-oriented programming, a programming paradigm that uses "services" as the unit of computer work, to design and implement integrated business applications and mission critical software programs. Many languages offer support for multiple paradigms, making the distinction more a matter of style than of technical capabilities. == Research == Conferences are important events for computer science research. During these conferences, researchers from the public and private sectors present their recent work and meet. Unlike in most other academic fields, in computer science, the prestige of conference papers is greater than that of journal publications. One proposed explanation for this is the quick development of this relatively new field requires rapid review and distribution of results, a task better handled by conferences than by journals. == See also == == Notes == == References == == Further reading == == External links == DBLP Computer Science Bibliography Association for Computing Machinery Institute of Electrical and Electronics Engineers
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Iteration is the repetition of a process in order to generate a (possibly unbounded) sequence of outcomes. Each repetition of the process is a single iteration, and the outcome of each iteration is then the starting point of the next iteration. In mathematics and computer science, iteration (along with the related technique of recursion) is a standard element of algorithms. == Mathematics == In mathematics, iteration may refer to the process of iterating a function, i.e. applying a function repeatedly, using the output from one iteration as the input to the next. Iteration of apparently simple functions can produce complex behaviors and difficult problems – for examples, see the Collatz conjecture and juggler sequences. Another use of iteration in mathematics is in iterative methods which are used to produce approximate numerical solutions to certain mathematical problems. Newton's method is an example of an iterative method. Manual calculation of a number's square root is a common use and a well-known example. == Computing == In computing, iteration is the technique marking out of a block of statements within a computer program for a defined number of repetitions. That block of statements is said to be iterated; a computer scientist might also refer to that block of statements as an "iteration". === Implementations === Loops constitute the most common language constructs for performing iterations. The following pseudocode "iterates" three times the line of code between begin & end through a for loop, and uses the values of i as increments. It is permissible, and often necessary, to use values from other parts of the program outside the bracketed block of statements, to perform the desired function. Iterators constitute alternative language constructs to loops, which ensure consistent iterations over specific data structures. They can eventually save time and effort in later coding attempts. In particular, an iterator allows one to repeat the same kind of operation at each node of such a data structure, often in some pre-defined order. Iteratees are purely functional language constructs, which accept or reject data during the iterations. === Relation with recursion === Recursions and iterations have different algorithmic definitions, even though they can generate identical effects/results. The primary difference is that recursion can be employed as a solution without prior knowledge as to how many times the action will have to repeat, while a successful iteration requires that foreknowledge. Some types of programming languages, known as functional programming languages, are designed such that they do not set up a block of statements for explicit repetition, as with the for loop. Instead, those programming languages exclusively use recursion. Rather than call out a block of code to be repeated a pre-defined number of times, the executing code block instead "divides" the work to be done into a number of separate pieces, after which the code block executes itself on each individual piece. Each piece of work will be divided repeatedly until the "amount" of work is as small as it can possibly be, at which point the algorithm will do that work very quickly. The algorithm then "reverses" and reassembles the pieces into a complete whole. The classic example of recursion is in list-sorting algorithms, such as merge sort. The merge sort recursive algorithm will first repeatedly divide the list into consecutive pairs; each pair is then ordered, then each consecutive pair of pairs, and so forth until the elements of the list are in the desired order. The code below is an example of a recursive algorithm in the Scheme programming language that will output the same result as the pseudocode under the previous heading. == Education == In some schools of pedagogy, iterations are used to describe the process of teaching or guiding students to repeat experiments, assessments, or projects, until more accurate results are found, or the student has mastered the technical skill. This idea is found in the old adage, "Practice makes perfect." In particular, "iterative" is defined as the "process of learning and development that involves cyclical inquiry, enabling multiple opportunities for people to revisit ideas and critically reflect on their implication." Unlike computing and math, educational iterations are not predetermined; instead, the task is repeated until success according to some external criteria (often a test) is achieved. == See also == Recursion Fractal Brute-force search Iterated function Infinite compositions of analytic functions == References ==
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Philosophy of science is the branch of philosophy concerned with the foundations, methods, and implications of science. Amongst its central questions are the difference between science and non-science, the reliability of scientific theories, and the ultimate purpose and meaning of science as a human endeavour. Philosophy of science focuses on metaphysical, epistemic and semantic aspects of scientific practice, and overlaps with metaphysics, ontology, logic, and epistemology, for example, when it explores the relationship between science and the concept of truth. Philosophy of science is both a theoretical and empirical discipline, relying on philosophical theorising as well as meta-studies of scientific practice. Ethical issues such as bioethics and scientific misconduct are often considered ethics or science studies rather than the philosophy of science. Many of the central problems concerned with the philosophy of science lack contemporary consensus, including whether science can infer truth about unobservable entities and whether inductive reasoning can be justified as yielding definite scientific knowledge. Philosophers of science also consider philosophical problems within particular sciences (such as biology, physics and social sciences such as economics and psychology). Some philosophers of science also use contemporary results in science to reach conclusions about philosophy itself. While philosophical thought pertaining to science dates back at least to the time of Aristotle, the general philosophy of science emerged as a distinct discipline only in the 20th century following the logical positivist movement, which aimed to formulate criteria for ensuring all philosophical statements' meaningfulness and objectively assessing them. Karl Popper criticized logical positivism and helped establish a modern set of standards for scientific methodology. Thomas Kuhn's 1962 book The Structure of Scientific Revolutions was also formative, challenging the view of scientific progress as the steady, cumulative acquisition of knowledge based on a fixed method of systematic experimentation and instead arguing that any progress is relative to a "paradigm", the set of questions, concepts, and practices that define a scientific discipline in a particular historical period. Subsequently, the coherentist approach to science, in which a theory is validated if it makes sense of observations as part of a coherent whole, became prominent due to W. V. Quine and others. Some thinkers such as Stephen Jay Gould seek to ground science in axiomatic assumptions, such as the uniformity of nature. A vocal minority of philosophers, and Paul Feyerabend in particular, argue against the existence of the "scientific method", so all approaches to science should be allowed, including explicitly supernatural ones. Another approach to thinking about science involves studying how knowledge is created from a sociological perspective, an approach represented by scholars like David Bloor and Barry Barnes. Finally, a tradition in continental philosophy approaches science from the perspective of a rigorous analysis of human experience. Philosophies of the particular sciences range from questions about the nature of time raised by Einstein's general relativity, to the implications of economics for public policy. A central theme is whether the terms of one scientific theory can be intra- or intertheoretically reduced to the terms of another. Can chemistry be reduced to physics, or can sociology be reduced to individual psychology? The general questions of philosophy of science also arise with greater specificity in some particular sciences. For instance, the question of the validity of scientific reasoning is seen in a different guise in the foundations of statistics. The question of what counts as science and what should be excluded arises as a life-or-death matter in the philosophy of medicine. Additionally, the philosophies of biology, psychology, and the social sciences explore whether the scientific studies of human nature can achieve objectivity or are inevitably shaped by values and by social relations. == Introduction == === Defining science === Distinguishing between science and non-science is referred to as the demarcation problem. For example, should psychoanalysis, creation science, and historical materialism be considered pseudosciences? Karl Popper called this the central question in the philosophy of science. However, no unified account of the problem has won acceptance among philosophers, and some regard the problem as unsolvable or uninteresting. Martin Gardner has argued for the use of a Potter Stewart standard ("I know it when I see it") for recognizing pseudoscience. Early attempts by the logical positivists grounded science in observation while non-science was non-observational and hence meaningless. Popper argued that the central property of science is falsifiability. That is, every genuinely scientific claim is capable of being proven false, at least in principle. An area of study or speculation that masquerades as science in an attempt to claim a legitimacy that it would not otherwise be able to achieve is referred to as pseudoscience, fringe science, or junk science. Physicist Richard Feynman coined the term "cargo cult science" for cases in which researchers believe they are doing science because their activities have the outward appearance of it but actually lack the "kind of utter honesty" that allows their results to be rigorously evaluated. === Scientific explanation === A closely related question is what counts as a good scientific explanation. In addition to providing predictions about future events, society often takes scientific theories to provide explanations for events that occur regularly or have already occurred. Philosophers have investigated the criteria by which a scientific theory can be said to have successfully explained a phenomenon, as well as what it means to say a scientific theory has explanatory power. One early and influential account of scientific explanation is the deductive-nomological model. It says that a successful scientific explanation must deduce the occurrence of the phenomena in question from a scientific law. This view has been subjected to substantial criticism, resulting in several widely acknowledged counterexamples to the theory. It is especially challenging to characterize what is meant by an explanation when the thing to be explained cannot be deduced from any law because it is a matter of chance, or otherwise cannot be perfectly predicted from what is known. Wesley Salmon developed a model in which a good scientific explanation must be statistically relevant to the outcome to be explained. Others have argued that the key to a good explanation is unifying disparate phenomena or providing a causal mechanism. === Justifying science === Although it is often taken for granted, it is not at all clear how one can infer the validity of a general statement from a number of specific instances or infer the truth of a theory from a series of successful tests. For example, a chicken observes that each morning the farmer comes and gives it food, for hundreds of days in a row. The chicken may therefore use inductive reasoning to infer that the farmer will bring food every morning. However, one morning, the farmer comes and kills the chicken. How is scientific reasoning more trustworthy than the chicken's reasoning? One approach is to acknowledge that induction cannot achieve certainty, but observing more instances of a general statement can at least make the general statement more probable. So the chicken would be right to conclude from all those mornings that it is likely the farmer will come with food again the next morning, even if it cannot be certain. However, there remain difficult questions about the process of interpreting any given evidence into a probability that the general statement is true. One way out of these particular difficulties is to declare that all beliefs about scientific theories are subjective, or personal, and correct reasoning is merely about how evidence should change one's subjective beliefs over time. Some argue that what scientists do is not inductive reasoning at all but rather abductive reasoning, or inference to the best explanation. In this account, science is not about generalizing specific instances but rather about hypothesizing explanations for what is observed. As discussed in the previous section, it is not always clear what is meant by the "best explanation". Ockham's razor, which counsels choosing the simplest available explanation, thus plays an important role in some versions of this approach. To return to the example of the chicken, would it be simpler to suppose that the farmer cares about it and will continue taking care of it indefinitely or that the farmer is fattening it up for slaughter? Philosophers have tried to make this heuristic principle more precise regarding theoretical parsimony or other measures. Yet, although various measures of simplicity have been brought forward as potential candidates, it is generally accepted that there is no such thing as a theory-independent measure of simplicity. In other words, there appear to be as many different measures of simplicity as there are theories themselves, and the task of choosing between measures of simplicity appears to be every bit as problematic as the job of choosing between theories. Nicholas Maxwell has argued for some decades that unity rather than simplicity is the key non-empirical factor in influencing the choice of theory in science, persistent preference for unified theories in effect committing science to the acceptance of a metaphysical thesis concerning unity in nature. In order to improve this problematic thesis, it needs to be represented in the form of a hierarchy of theses, each thesis becoming more insubstantial as one goes up the hierarchy. === Observation inseparable from theory === When making observations, scientists look through telescopes, study images on electronic screens, record meter readings, and so on. Generally, on a basic level, they can agree on what they see, e.g., the thermometer shows 37.9 degrees C. But, if these scientists have different ideas about the theories that have been developed to explain these basic observations, they may disagree about what they are observing. For example, before Albert Einstein's general theory of relativity, observers would have likely interpreted an image of the Einstein cross as five different objects in space. In light of that theory, however, astronomers will tell you that there are actually only two objects, one in the center and four different images of a second object around the sides. Alternatively, if other scientists suspect that something is wrong with the telescope and only one object is actually being observed, they are operating under yet another theory. Observations that cannot be separated from theoretical interpretation are said to be theory-laden. All observation involves both perception and cognition. That is, one does not make an observation passively, but rather is actively engaged in distinguishing the phenomenon being observed from surrounding sensory data. Therefore, observations are affected by one's underlying understanding of the way in which the world functions, and that understanding may influence what is perceived, noticed, or deemed worthy of consideration. In this sense, it can be argued that all observation is theory-laden. === The purpose of science === Should science aim to determine ultimate truth, or are there questions that science cannot answer? Scientific realists claim that science aims at truth and that one ought to regard scientific theories as true, approximately true, or likely true. Conversely, scientific anti-realists argue that science does not aim (or at least does not succeed) at truth, especially truth about unobservables like electrons or other universes. Instrumentalists argue that scientific theories should only be evaluated on whether they are useful. In their view, whether theories are true or not is beside the point, because the purpose of science is to make predictions and enable effective technology. Realists often point to the success of recent scientific theories as evidence for the truth (or near truth) of current theories. Antirealists point to either the many false theories in the history of science, epistemic morals, the success of false modeling assumptions, or widely termed postmodern criticisms of objectivity as evidence against scientific realism. Antirealists attempt to explain the success of scientific theories without reference to truth. Some antirealists claim that scientific theories aim at being accurate only about observable objects and argue that their success is primarily judged by that criterion. ==== Real patterns ==== The notion of real patterns has been propounded, notably by philosopher Daniel C. Dennett, as an intermediate position between strong realism and eliminative materialism. This concept delves into the investigation of patterns observed in scientific phenomena to ascertain whether they signify underlying truths or are mere constructs of human interpretation. Dennett provides a unique ontological account concerning real patterns, examining the extent to which these recognized patterns have predictive utility and allow for efficient compression of information. The discourse on real patterns extends beyond philosophical circles, finding relevance in various scientific domains. For example, in biology, inquiries into real patterns seek to elucidate the nature of biological explanations, exploring how recognized patterns contribute to a comprehensive understanding of biological phenomena. Similarly, in chemistry, debates around the reality of chemical bonds as real patterns continue. Evaluation of real patterns also holds significance in broader scientific inquiries. Researchers, like Tyler Millhouse, propose criteria for evaluating the realness of a pattern, particularly in the context of universal patterns and the human propensity to perceive patterns, even where there might be none. This evaluation is pivotal in advancing research in diverse fields, from climate change to machine learning, where recognition and validation of real patterns in scientific models play a crucial role. === Values and science === Values intersect with science in different ways. There are epistemic values that mainly guide the scientific research. The scientific enterprise is embedded in particular culture and values through individual practitioners. Values emerge from science, both as product and process and can be distributed among several cultures in the society. When it comes to the justification of science in the sense of general public participation by single practitioners, science plays the role of a mediator between evaluating the standards and policies of society and its participating individuals, wherefore science indeed falls victim to vandalism and sabotage adapting the means to the end. If it is unclear what counts as science, how the process of confirming theories works, and what the purpose of science is, there is considerable scope for values and other social influences to shape science. Indeed, values can play a role ranging from determining which research gets funded to influencing which theories achieve scientific consensus. For example, in the 19th century, cultural values held by scientists about race shaped research on evolution, and values concerning social class influenced debates on phrenology (considered scientific at the time). Feminist philosophers of science, sociologists of science, and others explore how social values affect science. == History == === Pre-modern === The origins of philosophy of science trace back to Plato and Aristotle, who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of abductive, deductive, and inductive inference, and also analyzed reasoning by analogy. The eleventh century Arab polymath Ibn al-Haytham (known in Latin as Alhazen) conducted his research in optics by way of controlled experimental testing and applied geometry, especially in his investigations into the images resulting from the reflection and refraction of light. Roger Bacon (1214–1294), an English thinker and experimenter heavily influenced by al-Haytham, is recognized by many to be the father of modern scientific method. His view that mathematics was essential to a correct understanding of natural philosophy is considered to have been 400 years ahead of its time. === Modern === Francis Bacon (no direct relation to Roger Bacon, who lived 300 years earlier) was a seminal figure in philosophy of science at the time of the Scientific Revolution. In his work Novum Organum (1620)—an allusion to Aristotle's Organon—Bacon outlined a new system of logic to improve upon the old philosophical process of syllogism. Bacon's method relied on experimental histories to eliminate alternative theories. In 1637, René Descartes established a new framework for grounding scientific knowledge in his treatise, Discourse on Method, advocating the central role of reason as opposed to sensory experience. By contrast, in 1713, the 2nd edition of Isaac Newton's Philosophiae Naturalis Principia Mathematica argued that "... hypotheses ... have no place in experimental philosophy. In this philosophy[,] propositions are deduced from the phenomena and rendered general by induction." This passage influenced a "later generation of philosophically-inclined readers to pronounce a ban on causal hypotheses in natural philosophy". In particular, later in the 18th century, David Hume would famously articulate skepticism about the ability of science to determine causality and gave a definitive formulation of the problem of induction, though both theses would be contested by the end of the 18th century by Immanuel Kant in his Critique of Pure Reason and Metaphysical Foundations of Natural Science. In 19th century Auguste Comte made a major contribution to the theory of science. The 19th century writings of John Stuart Mill are also considered important in the formation of current conceptions of the scientific method, as well as anticipating later accounts of scientific explanation. === Logical positivism === Instrumentalism became popular among physicists around the turn of the 20th century, after which logical positivism defined the field for several decades. Logical positivism accepts only testable statements as meaningful, rejects metaphysical interpretations, and embraces verificationism (a set of theories of knowledge that combines logicism, empiricism, and linguistics to ground philosophy on a basis consistent with examples from the empirical sciences). Seeking to overhaul all of philosophy and convert it to a new scientific philosophy, the Berlin Circle and the Vienna Circle propounded logical positivism in the late 1920s. Interpreting Ludwig Wittgenstein's early philosophy of language, logical positivists identified a verifiability principle or criterion of cognitive meaningfulness. From Bertrand Russell's logicism they sought reduction of mathematics to logic. They also embraced Russell's logical atomism, Ernst Mach's phenomenalism—whereby the mind knows only actual or potential sensory experience, which is the content of all sciences, whether physics or psychology—and Percy Bridgman's operationalism. Thereby, only the verifiable was scientific and cognitively meaningful, whereas the unverifiable was unscientific, cognitively meaningless "pseudostatements"—metaphysical, emotive, or such—not worthy of further review by philosophers, who were newly tasked to organize knowledge rather than develop new knowledge. Logical positivism is commonly portrayed as taking the extreme position that scientific language should never refer to anything unobservable—even the seemingly core notions of causality, mechanism, and principles—but that is an exaggeration. Talk of such unobservables could be allowed as metaphorical—direct observations viewed in the abstract—or at worst metaphysical or emotional. Theoretical laws would be reduced to empirical laws, while theoretical terms would garner meaning from observational terms via correspondence rules. Mathematics in physics would reduce to symbolic logic via logicism, while rational reconstruction would convert ordinary language into standardized equivalents, all networked and united by a logical syntax. A scientific theory would be stated with its method of verification, whereby a logical calculus or empirical operation could verify its falsity or truth. In the late 1930s, logical positivists fled Germany and Austria for Britain and America. By then, many had replaced Mach's phenomenalism with Otto Neurath's physicalism, and Rudolf Carnap had sought to replace verification with simply confirmation. With World War II's close in 1945, logical positivism became milder, logical empiricism, led largely by Carl Hempel, in America, who expounded the covering law model of scientific explanation as a way of identifying the logical form of explanations without any reference to the suspect notion of "causation". The logical positivist movement became a major underpinning of analytic philosophy, and dominated Anglosphere philosophy, including philosophy of science, while influencing sciences, into the 1960s. Yet the movement failed to resolve its central problems, and its doctrines were increasingly assaulted. Nevertheless, it brought about the establishment of philosophy of science as a distinct subdiscipline of philosophy, with Carl Hempel playing a key role. === Thomas Kuhn === In the 1962 book The Structure of Scientific Revolutions, Thomas Kuhn argued that the process of observation and evaluation takes place within a "paradigm", which he describes as "universally recognized achievements that for a time provide model problems and solutions to community of practitioners." A paradigm implicitly identifies the objects and relations under study and suggests what experiments, observations or theoretical improvements need to be carried out to produce a useful result. He characterized normal science as the process of observation and "puzzle solving" which takes place within a paradigm, whereas revolutionary science occurs when one paradigm overtakes another in a paradigm shift. Kurn was a historian of science, and his ideas were inspired by the study of older paradigms that have been discarded, such as Aristotelian mechanics or aether theory. These had often been portrayed by historians as using "unscientific" methods or beliefs. But careful examination showed that they were no less "scientific" than modern paradigms. Both were based on valid evidence, both failed to answer every possible question. A paradigm shift occurred when a significant number of observational anomalies arose in the old paradigm and efforts to resolve them within the paradigm were unsuccessful. A new paradigm was available that handled the anomalies with less difficulty and yet still covered (most of) the previous results. Over a period of time, often as long as a generation, more practitioners began working within the new paradigm and eventually the old paradigm was abandoned. For Kuhn, acceptance or rejection of a paradigm is a social process as much as a logical process. Kuhn's position, however, is not one of relativism; he wrote "terms like 'subjective' and 'intuitive' cannot be applied to [paradigms]." Paradigms are grounded in objective, observable evidence, but our use of them is psychological and our acceptance of them is social. == Current approaches == === Naturalism's axiomatic assumptions === According to Robert Priddy, all scientific study inescapably builds on at least some essential assumptions that cannot be tested by scientific processes; that is, that scientists must start with some assumptions as to the ultimate analysis of the facts with which it deals. These assumptions would then be justified partly by their adherence to the types of occurrence of which we are directly conscious, and partly by their success in representing the observed facts with a certain generality, devoid of ad hoc suppositions." Kuhn also claims that all science is based on assumptions about the character of the universe, rather than merely on empirical facts. These assumptions – a paradigm – comprise a collection of beliefs, values and techniques that are held by a given scientific community, which legitimize their systems and set the limitations to their investigation. For naturalists, nature is the only reality, the "correct" paradigm, and there is no such thing as supernatural, i.e. anything above, beyond, or outside of nature. The scientific method is to be used to investigate all reality, including the human spirit. Some claim that naturalism is the implicit philosophy of working scientists, and that the following basic assumptions are needed to justify the scientific method: That there is an objective reality shared by all rational observers."The basis for rationality is acceptance of an external objective reality." "Objective reality is clearly an essential thing if we are to develop a meaningful perspective of the world. Nevertheless its very existence is assumed." "Our belief that objective reality exist is an assumption that it arises from a real world outside of ourselves. As infants we made this assumption unconsciously. People are happy to make this assumption that adds meaning to our sensations and feelings, than live with solipsism." "Without this assumption, there would be only the thoughts and images in our own mind (which would be the only existing mind) and there would be no need of science, or anything else." That this objective reality is governed by natural laws; "Science, at least today, assumes that the universe obeys knowable principles that don't depend on time or place, nor on subjective parameters such as what we think, know or how we behave." Hugh Gauch argues that science presupposes that "the physical world is orderly and comprehensible." That reality can be discovered by means of systematic observation and experimentation.Stanley Sobottka said: "The assumption of external reality is necessary for science to function and to flourish. For the most part, science is the discovering and explaining of the external world." "Science attempts to produce knowledge that is as universal and objective as possible within the realm of human understanding." That Nature has uniformity of laws and most if not all things in nature must have at least a natural cause.Biologist Stephen Jay Gould referred to these two closely related propositions as the constancy of nature's laws and the operation of known processes. Simpson agrees that the axiom of uniformity of law, an unprovable postulate, is necessary in order for scientists to extrapolate inductive inference into the unobservable past in order to meaningfully study it. "The assumption of spatial and temporal invariance of natural laws is by no means unique to geology since it amounts to a warrant for inductive inference which, as Bacon showed nearly four hundred years ago, is the basic mode of reasoning in empirical science. Without assuming this spatial and temporal invariance, we have no basis for extrapolating from the known to the unknown and, therefore, no way of reaching general conclusions from a finite number of observations. (Since the assumption is itself vindicated by induction, it can in no way "prove" the validity of induction — an endeavor virtually abandoned after Hume demonstrated its futility two centuries ago)." Gould also notes that natural processes such as Lyell's "uniformity of process" are an assumption: "As such, it is another a priori assumption shared by all scientists and not a statement about the empirical world." According to R. Hooykaas: "The principle of uniformity is not a law, not a rule established after comparison of facts, but a principle, preceding the observation of facts ... It is the logical principle of parsimony of causes and of economy of scientific notions. By explaining past changes by analogy with present phenomena, a limit is set to conjecture, for there is only one way in which two things are equal, but there are an infinity of ways in which they could be supposed different." That experimental procedures will be done satisfactorily without any deliberate or unintentional mistakes that will influence the results. That experimenters won't be significantly biased by their presumptions. That random sampling is representative of the entire population.A simple random sample (SRS) is the most basic probabilistic option used for creating a sample from a population. The benefit of SRS is that the investigator is guaranteed to choose a sample that represents the population that ensures statistically valid conclusions. === Coherentism === In contrast to the view that science rests on foundational assumptions, coherentism asserts that statements are justified by being a part of a coherent system. Or, rather, individual statements cannot be validated on their own: only coherent systems can be justified. A prediction of a transit of Venus is justified by its being coherent with broader beliefs about celestial mechanics and earlier observations. As explained above, observation is a cognitive act. That is, it relies on a pre-existing understanding, a systematic set of beliefs. An observation of a transit of Venus requires a huge range of auxiliary beliefs, such as those that describe the optics of telescopes, the mechanics of the telescope mount, and an understanding of celestial mechanics. If the prediction fails and a transit is not observed, that is likely to occasion an adjustment in the system, a change in some auxiliary assumption, rather than a rejection of the theoretical system. According to the Duhem–Quine thesis, after Pierre Duhem and W.V. Quine, it is impossible to test a theory in isolation. One must always add auxiliary hypotheses in order to make testable predictions. For example, to test Newton's Law of Gravitation in the solar system, one needs information about the masses and positions of the Sun and all the planets. Famously, the failure to predict the orbit of Uranus in the 19th century led not to the rejection of Newton's Law but rather to the rejection of the hypothesis that the Solar System comprises only seven planets. The investigations that followed led to the discovery of an eighth planet, Neptune. If a test fails, something is wrong. But there is a problem in figuring out what that something is: a missing planet, badly calibrated test equipment, an unsuspected curvature of space, or something else. One consequence of the Duhem–Quine thesis is that one can make any theory compatible with any empirical observation by the addition of a sufficient number of suitable ad hoc hypotheses. Karl Popper accepted this thesis, leading him to reject naïve falsification. Instead, he favored a "survival of the fittest" view in which the most falsifiable scientific theories are to be preferred. === Anything goes methodology === Paul Feyerabend (1924–1994) argued that no description of scientific method could possibly be broad enough to include all the approaches and methods used by scientists, and that there are no useful and exception-free methodological rules governing the progress of science. He argued that "the only principle that does not inhibit progress is: anything goes". Feyerabend said that science started as a liberating movement, but that over time it had become increasingly dogmatic and rigid and had some oppressive features, and thus had become increasingly an ideology. Because of this, he said it was impossible to come up with an unambiguous way to distinguish science from religion, magic, or mythology. He saw the exclusive dominance of science as a means of directing society as authoritarian and ungrounded. Promulgation of this epistemological anarchism earned Feyerabend the title of "the worst enemy of science" from his detractors. === Sociology of scientific knowledge methodology === According to Kuhn, science is an inherently communal activity which can only be done as part of a community. For him, the fundamental difference between science and other disciplines is the way in which the communities function. Others, especially Feyerabend and some post-modernist thinkers, have argued that there is insufficient difference between social practices in science and other disciplines to maintain this distinction. For them, social factors play an important and direct role in scientific method, but they do not serve to differentiate science from other disciplines. On this account, science is socially constructed, though this does not necessarily imply the more radical notion that reality itself is a social construct. Michel Foucault sought to analyze and uncover how disciplines within the social sciences developed and adopted the methodologies used by their practitioners. In works like The Archaeology of Knowledge, he used the term human sciences. The human sciences do not comprise mainstream academic disciplines; they are rather an interdisciplinary space for the reflection on man who is the subject of more mainstream scientific knowledge, taken now as an object, sitting between these more conventional areas, and of course associating with disciplines such as anthropology, psychology, sociology, and even history. Rejecting the realist view of scientific inquiry, Foucault argued throughout his work that scientific discourse is not simply an objective study of phenomena, as both natural and social scientists like to believe, but is rather the product of systems of power relations struggling to construct scientific disciplines and knowledge within given societies. With the advances of scientific disciplines, such as psychology and anthropology, the need to separate, categorize, normalize and institutionalize populations into constructed social identities became a staple of the sciences. Constructions of what were considered "normal" and "abnormal" stigmatized and ostracized groups of people, like the mentally ill and sexual and gender minorities. However, some (such as Quine) do maintain that scientific reality is a social construct: Physical objects are conceptually imported into the situation as convenient intermediaries not by definition in terms of experience, but simply as irreducible posits comparable, epistemologically, to the gods of Homer ... For my part I do, qua lay physicist, believe in physical objects and not in Homer's gods; and I consider it a scientific error to believe otherwise. But in point of epistemological footing, the physical objects and the gods differ only in degree and not in kind. Both sorts of entities enter our conceptions only as cultural posits. The public backlash of scientists against such views, particularly in the 1990s, became known as the science wars. A major development in recent decades has been the study of the formation, structure, and evolution of scientific communities by sociologists and anthropologists – including David Bloor, Harry Collins, Bruno Latour, Ian Hacking and Anselm Strauss. Concepts and methods (such as rational choice, social choice or game theory) from economics have also been applied for understanding the efficiency of scientific communities in the production of knowledge. This interdisciplinary field has come to be known as science and technology studies. Here the approach to the philosophy of science is to study how scientific communities actually operate. === Continental philosophy === Philosophers in the continental philosophical tradition are not traditionally categorized as philosophers of science. However, they have much to say about science, some of which has anticipated themes in the analytical tradition. For example, in The Genealogy of Morals (1887) Friedrich Nietzsche advanced the thesis that the motive for the search for truth in sciences is a kind of ascetic ideal. In general, continental philosophy views science from a world-historical perspective. Philosophers such as Pierre Duhem (1861–1916) and Gaston Bachelard (1884–1962) wrote their works with this world-historical approach to science, predating Kuhn's 1962 work by a generation or more. All of these approaches involve a historical and sociological turn to science, with a priority on lived experience (a kind of Husserlian "life-world"), rather than a progress-based or anti-historical approach as emphasised in the analytic tradition. One can trace this continental strand of thought through the phenomenology of Edmund Husserl (1859–1938), the late works of Merleau-Ponty (Nature: Course Notes from the Collège de France, 1956–1960), and the hermeneutics of Martin Heidegger (1889–1976). The largest effect on the continental tradition with respect to science came from Martin Heidegger's critique of the theoretical attitude in general, which of course includes the scientific attitude. For this reason, the continental tradition has remained much more skeptical of the importance of science in human life and in philosophical inquiry. Nonetheless, there have been a number of important works: especially those of a Kuhnian precursor, Alexandre Koyré (1892–1964). Another important development was that of Michel Foucault's analysis of historical and scientific thought in The Order of Things (1966) and his study of power and corruption within the "science" of madness. Post-Heideggerian authors contributing to continental philosophy of science in the second half of the 20th century include Jürgen Habermas (e.g., Truth and Justification, 1998), Carl Friedrich von Weizsäcker (The Unity of Nature, 1980; German: Die Einheit der Natur (1971)), and Wolfgang Stegmüller (Probleme und Resultate der Wissenschaftstheorie und Analytischen Philosophie, 1973–1986). == Other topics == === Reductionism === Analysis involves breaking an observation or theory down into simpler concepts in order to understand it. Reductionism can refer to one of several philosophical positions related to this approach. One type of reductionism suggests that phenomena are amenable to scientific explanation at lower levels of analysis and inquiry. Perhaps a historical event might be explained in sociological and psychological terms, which in turn might be described in terms of human physiology, which in turn might be described in terms of chemistry and physics. Daniel Dennett distinguishes legitimate reductionism from what he calls greedy reductionism, which denies real complexities and leaps too quickly to sweeping generalizations. === Social accountability === A broad issue affecting the neutrality of science concerns the areas which science chooses to explore—that is, what part of the world and of humankind are studied by science. Philip Kitcher in his Science, Truth, and Democracy argues that scientific studies that attempt to show one segment of the population as being less intelligent, less successful, or emotionally backward compared to others have a political feedback effect which further excludes such groups from access to science. Thus such studies undermine the broad consensus required for good science by excluding certain people, and so proving themselves in the end to be unscientific. == Philosophy of particular sciences == There is no such thing as philosophy-free science; there is only science whose philosophical baggage is taken on board without examination. In addition to addressing the general questions regarding science and induction, many philosophers of science are occupied by investigating foundational problems in particular sciences. They also examine the implications of particular sciences for broader philosophical questions. The late 20th and early 21st century has seen a rise in the number of practitioners of philosophy of a particular science. === Philosophy of statistics === The problem of induction discussed above is seen in another form in debates over the foundations of statistics. The standard approach to statistical hypothesis testing avoids claims about whether evidence supports a hypothesis or makes it more probable. Instead, the typical test yields a p-value, which is the probability of the evidence being such as it is, under the assumption that the null hypothesis is true. If the p-value is too high, the hypothesis is rejected, in a way analogous to falsification. In contrast, Bayesian inference seeks to assign probabilities to hypotheses. Related topics in philosophy of statistics include probability interpretations, overfitting, and the difference between correlation and causation. === Philosophy of mathematics === Philosophy of mathematics is concerned with the philosophical foundations and implications of mathematics. The central questions are whether numbers, triangles, and other mathematical entities exist independently of the human mind and what is the nature of mathematical propositions. Is asking whether "1 + 1 = 2" is true fundamentally different from asking whether a ball is red? Was calculus invented or discovered? A related question is whether learning mathematics requires experience or reason alone. What does it mean to prove a mathematical theorem and how does one know whether a mathematical proof is correct? Philosophers of mathematics also aim to clarify the relationships between mathematics and logic, human capabilities such as intuition, and the material universe. === Philosophy of physics === Philosophy of physics is the study of the fundamental, philosophical questions underlying modern physics, the study of matter and energy and how they interact. The main questions concern the nature of space and time, atoms and atomism. Also included are the predictions of cosmology, the interpretation of quantum mechanics, the foundations of statistical mechanics, causality, determinism, and the nature of physical laws. Classically, several of these questions were studied as part of metaphysics (for example, those about causality, determinism, and space and time). === Philosophy of chemistry === Philosophy of chemistry is the philosophical study of the methodology and content of the science of chemistry. It is explored by philosophers, chemists, and philosopher-chemist teams. It includes research on general philosophy of science issues as applied to chemistry. For example, can all chemical phenomena be explained by quantum mechanics or is it not possible to reduce chemistry to physics? For another example, chemists have discussed the philosophy of how theories are confirmed in the context of confirming reaction mechanisms. Determining reaction mechanisms is difficult because they cannot be observed directly. Chemists can use a number of indirect measures as evidence to rule out certain mechanisms, but they are often unsure if the remaining mechanism is correct because there are many other possible mechanisms that they have not tested or even thought of. Philosophers have also sought to clarify the meaning of chemical concepts which do not refer to specific physical entities, such as chemical bonds. === Philosophy of astronomy === The philosophy of astronomy seeks to understand and analyze the methodologies and technologies used by experts in the discipline, focusing on how observations made about space and astrophysical phenomena can be studied. Given that astronomers rely and use theories and formulas from other scientific disciplines, such as chemistry and physics, the pursuit of understanding how knowledge can be obtained about the cosmos, as well as the relation in which Earth and the Solar System have within personal views of humanity's place in the universe, philosophical insights into how facts about space can be scientifically analyzed and configure with other established knowledge is a main point of inquiry. === Philosophy of Earth sciences === The philosophy of Earth science is concerned with how humans obtain and verify knowledge of the workings of the Earth system, including the atmosphere, hydrosphere, and geosphere (solid earth). Earth scientists' ways of knowing and habits of mind share important commonalities with other sciences, but also have distinctive attributes that emerge from the complex, heterogeneous, unique, long-lived, and non-manipulatable nature of the Earth system. === Philosophy of biology === Philosophy of biology deals with epistemological, metaphysical, and ethical issues in the biological and biomedical sciences. Although philosophers of science and philosophers generally have long been interested in biology (e.g., Aristotle, Descartes, Leibniz and even Kant), philosophy of biology only emerged as an independent field of philosophy in the 1960s and 1970s. Philosophers of science began to pay increasing attention to developments in biology, from the rise of the modern synthesis in the 1930s and 1940s to the discovery of the structure of deoxyribonucleic acid (DNA) in 1953 to more recent advances in genetic engineering. Other key ideas such as the reduction of all life processes to biochemical reactions as well as the incorporation of psychology into a broader neuroscience are also addressed. Research in current philosophy of biology includes investigation of the foundations of evolutionary theory (such as Peter Godfrey-Smith's work), and the role of viruses as persistent symbionts in host genomes. As a consequence, the evolution of genetic content order is seen as the result of competent genome editors in contrast to former narratives in which error replication events (mutations) dominated. === Philosophy of medicine === Beyond medical ethics and bioethics, the philosophy of medicine is a branch of philosophy that includes the epistemology and ontology/metaphysics of medicine. Within the epistemology of medicine, evidence-based medicine (EBM) (or evidence-based practice (EBP)) has attracted attention, most notably the roles of randomisation, blinding and placebo controls. Related to these areas of investigation, ontologies of specific interest to the philosophy of medicine include Cartesian dualism, the monogenetic conception of disease and the conceptualization of 'placebos' and 'placebo effects'. There is also a growing interest in the metaphysics of medicine, particularly the idea of causation. Philosophers of medicine might not only be interested in how medical knowledge is generated, but also in the nature of such phenomena. Causation is of interest because the purpose of much medical research is to establish causal relationships, e.g. what causes disease, or what causes people to get better. === Philosophy of psychiatry === Philosophy of psychiatry explores philosophical questions relating to psychiatry and mental illness. The philosopher of science and medicine Dominic Murphy identifies three areas of exploration in the philosophy of psychiatry. The first concerns the examination of psychiatry as a science, using the tools of the philosophy of science more broadly. The second entails the examination of the concepts employed in discussion of mental illness, including the experience of mental illness, and the normative questions it raises. The third area concerns the links and discontinuities between the philosophy of mind and psychopathology. === Philosophy of psychology === Philosophy of psychology refers to issues at the theoretical foundations of modern psychology. Some of these issues are epistemological concerns about the methodology of psychological investigation. For example, is the best method for studying psychology to focus only on the response of behavior to external stimuli or should psychologists focus on mental perception and thought processes? If the latter, an important question is how the internal experiences of others can be measured. Self-reports of feelings and beliefs may not be reliable because, even in cases in which there is no apparent incentive for subjects to intentionally deceive in their answers, self-deception or selective memory may affect their responses. Then even in the case of accurate self-reports, how can responses be compared across individuals? Even if two individuals respond with the same answer on a Likert scale, they may be experiencing very different things. Other issues in philosophy of psychology are philosophical questions about the nature of mind, brain, and cognition, and are perhaps more commonly thought of as part of cognitive science, or philosophy of mind. For example, are humans rational creatures? Is there any sense in which they have free will, and how does that relate to the experience of making choices? Philosophy of psychology also closely monitors contemporary work conducted in cognitive neuroscience, psycholinguistics, and artificial intelligence, questioning what they can and cannot explain in psychology. Philosophy of psychology is a relatively young field, because psychology only became a discipline of its own in the late 1800s. In particular, neurophilosophy has just recently become its own field with the works of Paul Churchland and Patricia Churchland. Philosophy of mind, by contrast, has been a well-established discipline since before psychology was a field of study at all. It is concerned with questions about the very nature of mind, the qualities of experience, and particular issues like the debate between dualism and monism. === Philosophy of social science === The philosophy of social science is the study of the logic and method of the social sciences, such as sociology and cultural anthropology. Philosophers of social science are concerned with the differences and similarities between the social and the natural sciences, causal relationships between social phenomena, the possible existence of social laws, and the ontological significance of structure and agency. The French philosopher, Auguste Comte (1798–1857), established the epistemological perspective of positivism in The Course in Positivist Philosophy, a series of texts published between 1830 and 1842. The first three volumes of the Course dealt chiefly with the natural sciences already in existence (geoscience, astronomy, physics, chemistry, biology), whereas the latter two emphasised the inevitable coming of social science: "sociologie". For Comte, the natural sciences had to necessarily arrive first, before humanity could adequately channel its efforts into the most challenging and complex "Queen science" of human society itself. Comte offers an evolutionary system proposing that society undergoes three phases in its quest for the truth according to a general 'law of three stages'. These are (1) the theological, (2) the metaphysical, and (3) the positive. Comte's positivism established the initial philosophical foundations for formal sociology and social research. Durkheim, Marx, and Weber are more typically cited as the fathers of contemporary social science. In psychology, a positivistic approach has historically been favoured in behaviourism. Positivism has also been espoused by 'technocrats' who believe in the inevitability of social progress through science and technology. The positivist perspective has been associated with 'scientism'; the view that the methods of the natural sciences may be applied to all areas of investigation, be it philosophical, social scientific, or otherwise. Among most social scientists and historians, orthodox positivism has long since lost popular support. Today, practitioners of both social and physical sciences instead take into account the distorting effect of observer bias and structural limitations. This scepticism has been facilitated by a general weakening of deductivist accounts of science by philosophers such as Thomas Kuhn, and new philosophical movements such as critical realism and neopragmatism. The philosopher-sociologist Jürgen Habermas has critiqued pure instrumental rationality as meaning that scientific-thinking becomes something akin to ideology itself. === Philosophy of technology === The philosophy of technology is a sub-field of philosophy that studies the nature of technology. Specific research topics include study of the role of tacit and explicit knowledge in creating and using technology, the nature of functions in technological artifacts, the role of values in design, and ethics related to technology. Technology and engineering can both involve the application of scientific knowledge. The philosophy of engineering is an emerging sub-field of the broader philosophy of technology. == See also == == References == === Sources === == Further reading == == External links == Philosophy of science at PhilPapers Philosophy of science at the Indiana Philosophy Ontology Project "Philosophy of science". Internet Encyclopedia of Philosophy.
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https://en.wikipedia.org/wiki/Philosophy_of_science
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Discovery science (also known as discovery-based science) is a scientific methodology which aims to find new patterns, correlations, and form hypotheses through the analysis of large-scale experimental data. The term “discovery science” encompasses various fields of study, including basic, translational, and computational science and research. Discovery-based methodologies are commonly contrasted with traditional scientific practice, the latter involving hypothesis formation before experimental data is closely examined. Discovery science involves the process of inductive reasoning or using observations to make generalisations, and can be applied to a range of science-related fields, e.g., medicine, proteomics, hydrology, psychology, and psychiatry. == Overview == === Purpose === Discovery science places an emphasis on 'basic' discovery, which can fundamentally change the status quo. For example, in the early years of water resources research, the use of discovery science was demonstrated by seeking to elucidate phenomena that was, until that point, unexplained. It did not matter how unusual these ideas may have been perceived to be. In this sense, discovery science is based on the attitude that ‘‘we must not allow our concepts of the earth, in so far as they transcend the reach of observation, to root themselves so deeply and so firmly in our minds that the process of uprooting them causes mental discomfort" (as stated by Davis in 1926). For discovery science to be utilised, there is a need to revert to creating and testing genuine hypotheses, rather than focusing on praising concepts that are already familiar. While researchers commonly feel that new hypotheses will naturally emerge inductively from curiosity in the relevant field, it should be acknowledged that hypotheses can be generated by models. Additionally, deductive testing must involve field observation, so that imperfect answers can be substituted with questions that are more clearly defined. === Tools === Hypothesis-driven studies can be transformed into discovery-driven studies with the help of newly available tools and technology-driven life science research. These tools have allowed for new questions to be asked, and new paradigms to be considered, particularly in the field of biology. However, some of these required tools are limited in the sense that they are inaccessible or too costly because the related technology is still being developed. Data mining is the most common tool used in discovery science, and is applied to data from diverse fields of study such as DNA analysis, climate modelling, nuclear reaction modelling, and others. The use of data mining in discovery science follows a general trend of increasing use of computers and computational theory in all fields of science, and newer methods of data mining employ specialised machine learning algorithms for automated hypothesis forming and automated theorem proving. == Applications == While computational methods are gaining interest, there is a decline in efforts to support critical care through basic and translational science, i.e., forms of discovery science which are essential for advancing understanding of pathophysiology. A loss of interest in basic and translational science may lead to a failure to discover and develop new therapies, which could have an impact on the critically ill. Within critical care, there is an aim to renew emphasis on basic, translational science through platforms such as medical journals and conferences, as well as the critical care medical curricula. Advances in discovery-based science thereby underlie key discoveries and development in medicine, constituting a 'pipeline' for leading-edge medical development. === Medicine === According to the AACR Cancer Progress Report 2021, discovery science has the potential to drive clinical breakthroughs. Since discovery science underlies key discoveries and development of new therapies for medicine, it remains important for advancing critical care. Numerous discoveries have increased life span and productivity, and decreased health-related costs, thereby revolutionising medical care. Resultantly, return on investment for discovery science has proven to be high. For example, its combination of computational methods with knowledge on inflammatory and genomic pathways has resulted in optimised clinical trials. Ultimately, discovery science is currently enabling a transition to the era of personalised medicine for treating complex syndromes, e.g., sepsis and ARDS. With a robust infrastructure, discovery science can resultantly revolutionise medical care and biological research. === Genomics === Discovery science has converged with clinical medicine and cancer genomics, and this convergence has been accelerated by recent advances in genome technologies and genomic information. The effect of cancer genomics has been noticeable in every area of cancer research. The majority of successful applications of genomic knowledge in today's clinical medicine involves a wealth of knowledge which has been gathered by a broad range of research and decades of work. Biological insights are required to inform drug discovery and to set a clear clinical path for development. Historically, acquisition of such knowledge through functional and mechanistic studies has been uncoordinated, random, and inefficient. The process of moving from cancer genomic discoveries to personalised medicine involves some major scientific, logistical and regulatory hurdles. This includes patient consent, sample acquisition, clinical annotation and study design, all of which can lead to data generation and computational analyses. Additionally, functional and mechanistic studies remain a challenge, which can lead to drug and biomarker discovery and development, commercial challenges and genomics-informed clinical trials. Importantly, these key scientific challenges are interdependent with each other. Directed and streamlined approaches are sought to be developed for a rapid generation of biological discoveries, which can allow for cancer genomic discoveries to translate to the clinic. Delivering personalised cancer medicine benefits from traditional, unconstrained and non-directed academic exploration, with the goal of directing scientific inquiry to convert genomic discovery to diagnostic and therapeutic targets. === Proteomics === Another example of discovery science is proteomics, a technology-driven and technology limited discovery science. Technologies for proteomic analysis provide information that is useful in discovery science. Proteome analysis as a discovery science is applicable in biotechnology, e.g., it assists in 1) the discovery of biochemical pathways which can identify targets for therapies, 2) developing new processes for manufacturing biological materials, 3) monitoring manufacturing processes for the purpose of quality control, and 4) developing diagnostic tests and efficacious treatment strategies for clinical diseases. In the context of proteomics, current life-science research remains technology-limited, however, recent available tools have assisted in evolving such research from being hypothesis-driven to discovery-driven. === Hydrology === Field hydrology has experienced a decline in progress due to a change from discovery-based field work to the gathering of data for modal parameterisation. In field hydrology, models are not any more useful than an understanding of how systems work, and discovery science allows for this understanding. Several important examples of field-based inquiry and discovery have taken place in field hydrology. These include: identifying spatial patterns of soil moisture and how they relate to topography; interrogating such data through the use of geostatistics; and discovering the importance of macropore flow and hydrological connectivity. Some discovery-based questions that have been asked in field hydrology include 1) determining which parts of the watershed are most important in determining water delivery to the channel, 2) how the presence of 'old' water can be explained by groundwater travelling into the stream, and 3) how there can be an explanation for flashy hydrographs when there is no overland flow visible. Therefore, there is a need for discovery science in field hydrology, despite any unusual hydrological hypotheses that are formed. === Psychology === An example of discovery science being enhanced for human brain function can be seen in the 1000 Functional Connectomes Project (FCP). This project was launched in 2009 as a way of generating and collecting functional magnetic resonance imaging (fMRI) data from over 1,000 individuals. Similarly to decoding the human genome, the mapping of human brain function presents challenges to the functional neuroimaging community. For the first phase of discovery science, it is necessary to accumulate and share large-scale datasets for data mining. Traditionally, the neuroimaging community within psychology has focused on task-based and hypothesis-driven approaches, however, a powerful tool for discovery science has emerged in the form of resting-state functional MRI (R-fMRI). The potential of discovery science remains vast, e.g. 1) helping with decision-making and guiding clinical diagnoses by developing objective measures of brain functional integrity, 2) assessing the level of efficacy of treatment interventions, and 3) tracking responses to treatment. Among the scientific community, recruiting participation and achieving collaboration from the broad population is essential for successfully implementing discovery-based science in the context of human brain function. == Methodology == Discovery-based methodologies are often viewed in contrast to traditional scientific practice, where hypotheses are formed before close examination of experimental data. However, from a philosophical perspective where all or most of the observable "low-hanging fruit" has already been plucked, examining the phenomenological world more closely than the senses alone (even augmented senses, e.g. via microscopes, telescopes, bifocals etc.) opens a new source of knowledge for hypothesis formation. This process is also known as inductive reasoning or the use of specific observations to make generalisations. Discovery science is usually a complex process, and consequently does not follow a simple linear cause and effect pattern. This means that outcomes are uncertain, and it is expected to have disappointing results as a fundamental part of discovery science. In particular, this may apply to medicine for the critically ill, where disease syndromes may be complex and multi-factorial. In psychiatry, studying complex relationships between brain and behaviour requires a large-scale science. This calls for a need to conceptually switch from hypothesis-driven studies to hypothesis-generating research which is discovery-based. Normally, discovery-based approaches for research are initially hypothesis-free, however, hypothesis testing can be elevated to a new level that effectively supports traditional hypothesis-driven studies. Researchers hope that combining integrative analyses of data from a range of different levels can result in new classification approaches to enable personalised interventions. Some biologists, such as Leroy Hood, have suggested that the model of ‘discovery science’ is a model which certain research fields are heading towards. For example, it is believed that more information about gene function can be discovered, through the evolution of data-mining tools. Discovery-based approaches are often referred to as “big data” approaches, because of the large-scale datasets that they involve analyses of. Big data includes large-scale homogenous study designs and highly variant datasets, and can be further divided into different kinds of datasets. For example, in neuropsychiatric studies, big data can be categorised as ‘broad’ or ‘deep’ data. Broad data is complex and heterogenous, as it is collected from multiple sources (e.g., labs and institutions) and uses different kinds of standards. On the other hand, deep data is collected at multiple levels, e.g., from genes to molecules, cells, circuits, behaviours, and symptoms. Broad data allows for population level inferences to be made; deep data is required for personalised medicine. However, combining broad and deep data and storing them in large-scale databases makes it practically impossible to rely on traditional statistical approaches. Instead, the use of discovery-based big data approaches can allow for the generation of hypotheses and offer an analytical tool with high-throughput for pattern recognition and data mining. It is in this way that discovery-based approaches can provide insight into causes and mechanisms of the area of study. Although discovery-based and data-driven big data approaches can inform understanding of mechanisms behind the topic of concern, the success of these approaches depends on integrated analyses of the various types of relevant data, and the resultant insight provided. For example, when researching psychiatric dysfunction, it is important to integrate vast and complex data such as brain imaging, genomic data and behavioural data, to uncover any brain-behaviour connections that are relevant to psychiatric dysfunction. Therefore, there are challenges to integrating data and developing mining tools. Furthermore, validation of results is a big challenge for discovery-based science. Although it is possible for results to be statistically validated by independent datasets, tests of functionality affect ultimate validation. Collaborative efforts are therefore critical for success. == References == Chen, J.; Call, G. B.; Beyer, E.; Bui, C.; Cespedes, A.; Chan, A.; Chan, J .; Chan, S.; Chhabra, A. (February 2005). "Discovery-Based Science Education: Functional Genomic Dissection in Drosophila by Undergraduate Researchers". PLOS Biology. 3 (2): e59. doi:10.1371/journal.pbio.0030059. PMC 548953. PMID 15719063.
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In the GCSE system in England and Wales, science at GCSE level is studied through Biology, Chemistry and Physics. == Double Award == Combined Science results in two GCSEs. Those with GCSEs in Combined Science can progress to A Levels in all of the three natural science subjects. Prior to this, around 1996, Combined Science GCSEs were available as an alternative to three separate Sciences for many exam boards. Combined Science consists of either Higher Tier (HT) or Foundation Tier (FT) papers AQA offer two different specifications entitled Synergy and Trilogy. == Triple Award == Triple Award Science, commonly referred to as Triple Science, results in three separate GCSEs in Biology, Chemistry and Physics and provide the broadest coverage of the main three science subjects. The qualifications are offered by the five main awarding bodies in England; AQA, Edexcel, OCR, CIE and Eduqas. == History == In August 2018, Ofqual announced that it had intervened to adjust the GCSE Science grade boundaries for students who had taken the "higher tier" paper in its new double award science exams and performed poorly, due to an excessive number of students in danger of receiving a grade of "U" or "unclassified". == Criticisms == In 2020, Teach First published a report stating that only two female scientists, chemist and crystallographer Rosalind Franklin and paleoanthropologist Mary Leakey, were included in the GCSE Science curriculum, versus 40 male scientists who were named. The report argued that the lack of female role models in the science curriculum was perpetuating gender biases in the profession. == References ==
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https://en.wikipedia.org/wiki/GCSE_Science
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Junk science is spurious or fraudulent scientific data, research, or analysis. The concept is often invoked in political and legal contexts where facts and scientific results have a great amount of weight in making a determination. It usually conveys a pejorative connotation that the research has been untowardly driven by political, ideological, financial, or otherwise unscientific motives. The concept was popularized in the 1990s in relation to expert testimony in civil litigation. More recently, invoking the concept has been a tactic to criticize research on the harmful environmental or public health effects of corporate activities, and occasionally in response to such criticism. In some contexts, junk science is counterposed to the "sound science" or "solid science" that favors one's own point of view. Junk science has been criticized for undermining public trust in real science.: 110–111 Junk science is not the same as pseudoscience. == Definition == Junk science has been defined as: "science done to establish a preconceived notion—not to test the notion, which is what proper science tries to do, but to establish it regardless of whether or not it would hold up to real testing." "opinion posing as empirical evidence, or through evidence of questionable warrant, based on inadequate scientific methodology." "methodologically sloppy research conducted to advance some extrascientific agenda or to prevail in litigation." == Motivations == Junk science happens for different reasons: researchers believing that their ideas are correct before proper analysis (a sort of scientific self-delusion or drinking the Kool-Aid), researchers biased with their study designs, and/or a "plain old lack of ethics". Being overly attached to one's own ideas can cause research to veer from ordinary junk science (e.g., designing an experiment that is expected to produce the desired results) into scientific fraud (e.g., lying about the results) and pseudoscience (e.g., claiming that the unfavorable results actually proved the idea correct). Junk science can occur when the perpetrator has something to gain from arriving at the desired conclusion. It can often happen in the testimony of expert witnesses in legal proceedings, and especially in the self-serving advertising of products and services. These situations may encourage researchers to make sweeping or overstated claims based on limited evidence. == History == The phrase junk science appears to have been in use prior to 1985. A 1985 United States Department of Justice report by the Tort Policy Working Group noted: The use of such invalid scientific evidence (commonly referred to as 'junk science') has resulted in findings of causation which simply cannot be justified or understood from the standpoint of the current state of credible scientific or medical knowledge. In 1989, the climate scientist Jerry Mahlman (Director of the Geophysical Fluid Dynamics Laboratory) characterized the theory that global warming was due to solar variation (presented in Scientific Perspectives on the Greenhouse Problem by Frederick Seitz et al.) as "noisy junk science." Peter W. Huber popularized the term with respect to litigation in his 1991 book Galileo's Revenge: Junk Science in the Courtroom. The book has been cited in over 100 legal textbooks and references; as a consequence, some sources cite Huber as the first to coin the term. By 1997, the term had entered the legal lexicon as seen in an opinion by Supreme Court of the United States Justice John Paul Stevens: An example of 'junk science' that should be excluded under the Daubert standard as too unreliable would be the testimony of a phrenologist who would purport to prove a defendant's future dangerousness based on the contours of the defendant's skull. Lower courts have subsequently set guidelines for identifying junk science, such as the 2005 opinion of United States Court of Appeals for the Seventh Circuit Judge Frank H. Easterbrook: Positive reports about magnetic water treatment are not replicable; this plus the lack of a physical explanation for any effects are hallmarks of junk science. As the subtitle of Huber's book, Junk Science in the Courtroom, suggests, his emphasis was on the use or misuse of expert testimony in civil litigation. One prominent example cited in the book was litigation over casual contact in the spread of AIDS. A California school district sought to prevent a young boy with AIDS, Ryan Thomas, from attending kindergarten. The school district produced an expert witness, Steven Armentrout, who testified that a possibility existed that AIDS could be transmitted to schoolmates through yet undiscovered "vectors". However, five experts testified on behalf of Thomas that AIDS is not transmitted through casual contact, and the court affirmed the "solid science" (as Huber called it) and rejected Armentrout's argument. In 1999, Paul Ehrlich and others advocated public policies to improve the dissemination of valid environmental scientific knowledge and discourage junk science: The Intergovernmental Panel on Climate Change reports offer an antidote to junk science by articulating the current consensus on the prospects for climate change, by outlining the extent of the uncertainties, and by describing the potential benefits and costs of policies to address climate change. In a 2003 study about changes in environmental activism regarding the Crown of the Continent Ecosystem, Pedynowski noted that junk science can undermine the credibility of science over a much broader scale because misrepresentation by special interests casts doubt on more defensible claims and undermines the credibility of all research. In his 2006 book Junk Science, Dan Agin emphasized two main causes of junk science: fraud, and ignorance. In the first case, Agin discussed falsified results in the development of organic transistors: As far as understanding junk science is concerned, the important aspect is that both Bell Laboratories and the international physics community were fooled until someone noticed that noise records published by Jan Hendrik Schön in several papers were identical—which means physically impossible. In the second case, he cites an example that demonstrates ignorance of statistical principles in the lay press: Since no such proof is possible [that genetically modified food is harmless], the article in The New York Times was what is called a "bad rap" against the U.S. Department of Agriculture—a bad rap based on a junk-science belief that it's possible to prove a null hypothesis. Agin asks the reader to step back from the rhetoric, as "how things are labeled does not make a science junk science." In its place, he offers that junk science is ultimately motivated by the desire to hide undesirable truths from the public. The rise of open source (free to read) journals has resulted in economic pressure on academic publishers to publish junk science. Even when the journal is peer-reviewed, the authors, rather than the readers, become the customer and the source of funding for the journal, so the publisher is incentivized to publish as many papers as possible, including those that are methodologically unsound. == Misuse in public relations == John Stauber and Sheldon Rampton of PR Watch say the concept of junk science has come to be invoked in attempts to dismiss scientific findings that stand in the way of short-term corporate profits. In their book Trust Us, We're Experts (2001), they write that industries have launched multimillion-dollar campaigns to position certain theories as junk science in the popular mind, often failing to employ the scientific method themselves. For example, the tobacco industry has described research demonstrating the harmful effects of smoking and second-hand smoke as junk science, through the vehicle of various astroturf groups. Theories more favorable to corporate activities are portrayed in words as "sound science". Past examples where "sound science" was used include the research into the toxicity of Alar, which was heavily criticized by antiregulatory advocates, and Herbert Needleman's research into low dose lead poisoning. Needleman was accused of fraud and personally attacked. Fox News commentator Steven Milloy often denigrates credible scientific research on topics like global warming, ozone depletion, and passive smoking as "junk science". The credibility of Milloy's website junkscience.com was questioned by Paul D. Thacker, a writer for The New Republic, in the wake of evidence that Milloy had received funding from Philip Morris, RJR Tobacco, and ExxonMobil. Thacker also noted that Milloy was receiving almost $100,000 a year in consulting fees from Philip Morris while he criticized the evidence regarding the hazards of second-hand smoke as junk science. Following the publication of this article, the Cato Institute, which had hosted the junkscience.com site, ceased its association with the site and removed Milloy from its list of adjunct scholars. Tobacco industry documents reveal that Philip Morris executives conceived of the "Whitecoat Project" in the 1980s as a response to emerging scientific data on the harmfulness of second-hand smoke. The goal of the Whitecoat Project, as conceived by Philip Morris and other tobacco companies, was to use ostensibly independent "scientific consultants" to spread doubt in the public mind about scientific data through invoking concepts like junk science. According to epidemiologist David Michaels, Assistant Secretary of Energy for Environment, Safety, and Health in the Clinton Administration, the tobacco industry invented the "sound science" movement in the 1980s as part of their campaign against the regulation of second-hand smoke. David Michaels has argued that, since the U.S. Supreme Court ruling in Daubert v. Merrell Dow Pharmaceuticals, Inc., lay judges have become "gatekeepers" of scientific testimony and, as a result, respected scientists have sometimes been unable to provide testimony so that corporate defendants are "increasingly emboldened" to accuse adversaries of practicing junk science. == Notable cases == American psychologist Paul Cameron has been designated by the Southern Poverty Law Center (SPLC) as an anti-gay extremist and a purveyor of "junk science". Cameron's research has been heavily criticized for unscientific methods and distortions which attempt to link homosexuality with pedophilia. In one instance, Cameron claimed that lesbians are 300 times more likely to get into car accidents. The SPLC states his work has been continually cited in some sections of the media despite being discredited. Cameron was expelled from the American Psychological Association in 1983. == Combatting junk science == In 1995, the Union of Concerned Scientists launched the Sound Science Initiative, a national network of scientists committed to debunking junk science through media outreach, lobbying, and developing joint strategies to participate in town meetings or public hearings. In its newsletter on Science and Technology in Congress, the American Association for the Advancement of Science also recognized the need for increased understanding between scientists and lawmakers: "Although most individuals would agree that sound science is preferable to junk science, fewer recognize what makes a scientific study 'good' or 'bad'." The American Dietetic Association, criticizing marketing claims made for food products, has created a list of "Ten Red Flags of Junk Science". == See also == == References == == Further reading == Agin, Dan (2006). Junk Science – How Politicians, Corporations, and Other Hucksters Betray Us. St. Martin's Griffin. ISBN 978-0312374808. Archived from the original on 2023-11-04. Retrieved 2016-10-18. Huber, Peter W. (1993). Galileo's Revenge: Junk Science in the Courtroom. Basic Books. ISBN 978-0465026241. Mooney, Chris (2005). The Republican War on Science. Basic Books. ISBN 978-0465046751. Kiss Sarnoff, Susan (2001). Sanctified Snake Oil: The Effect of Junk Science on Public Policy. Bloomsbury Academic. ISBN 978-0275968458. == External links == Project on Scientific Knowledge and Public Policy(SKAPP) DefendingScience.org Michaels, David (June 2005). "Doubt is Their Product". Scientific American. 292 (6): 96–101. Bibcode:2005SciAm.292f..96M. doi:10.1038/scientificamerican0605-96. PMID 15934658. Archived from the original on 2007-09-27. Retrieved 2008-06-03. Baba, Annamaria; Cook, Daniel M.; McGarity, Thomas O.; Bero, Lisa A. (July 2005). "Legislating 'Sound Science': The Role of the Tobacco Industry". American Journal of Public Health. 95 (1): 20–27. doi:10.2105/AJPH.2004.050963. hdl:10.2105/AJPH.2004.050963. PMID 16030333. Archived from the original on 2008-05-10. Retrieved 2008-06-03. Michaels, David; Monforton, Celeste (July 2005). "Manufacturing Uncertainty: Contested Science and the Protection of the Public's Health & Environment". American Journal of Public Health. 95 (1): 39–48. CiteSeerX 10.1.1.620.6171. doi:10.2105/AJPH.2004.043059. PMID 16030337. Archived from the original on 2008-05-10. Retrieved 2008-06-03. Yach, Derek; Aguinaga Bialous, Stella (November 2001). "Junking Science to Promote Tobacco". American Journal of Public Health. 91 (11): 1745–1748. doi:10.2105/ajph.91.11.1745. PMC 1446867. PMID 11684592. Thacker, Paul D. (May 11, 2005). "The Junkman Climbs to the Top". Environmental Science & Technology. Archived from the original on June 20, 2005. Retrieved August 7, 2017. Baloney Detection Kit on YouTube (10 questions we should ask when encountering a pseudoscience claim)
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Oregon Health & Science University (OHSU) is a public research university focusing primarily on health sciences with a main campus, including two hospitals, in Portland, Oregon. The institution was founded in 1887 as the University of Oregon Medical Department and later became the University of Oregon Medical School. In 1974, the campus became an independent, self-governed institution called the University of Oregon Health Sciences Center, combining state dentistry, medicine, nursing, and public health programs into a single center. It was renamed Oregon Health Sciences University in 1981 and took its current name in 2001, as part of a merger with the Oregon Graduate Institute (OGI), in Hillsboro. The university has several partnership programs including a joint PharmD Pharmacy program with Oregon State University in Corvallis. It is designated as a "Special Focus – Research Institution" according to the Carnegie Classification. == History == The Willamette University School of Medicine, OHSU's earliest predecessor, was founded in the 1860s in Salem, and was relocated to Portland in the 1870s. In 1915, Willamette University and the University of Oregon merged their medical programs to form the University of Oregon Medical School, and in 1919 the school moved to its present location on Marquam Hill in Southwest Portland. The Oregon-Washington Railroad and Navigation Company donated 20 acres (8.1 ha) and C.S. "Sam" Jackson, publisher of the now-defunct Oregon Journal donated the remaining 88 acres (36 ha) to the school two years prior to the move after the property had been deemed unsuitable for the construction of a railroad yard. Over the next forty years, the school diversified its educational offerings to include nursing and dental programs, and expanded with facilities built during this time on Marquam Hill, including the Multnomah County Hospital, the Doernbecher Children's Hospital, and an outpatient clinic. In 1955, Oregon state senator Mark Hatfield co-sponsored a bill to extend the medical school with a teaching hospital, and in 1974 the State of Oregon merged the institutions located on Marquam Hill into the University Hospital independent of the University of Oregon. Hatfield's continued support of medical research in Oregon in general and the hospital in particular was recognized by the institution in 1998 with the dedication of the Mark O. Hatfield Clinical Research Center, and the creation of the Hatfield information wall on permanent display in the lobby of the main hospital. In 2008, Governor Kulongoski released an executive order designating the Mark O. Hatfield Chair of the OHSU Board of Directors to commemorate Hatfield's commitment to the institution. The Oregon Graduate Institute merged with OHSU in July 2001, with OGI becoming the OGI School of Science and Engineering, one of four schools within OHSU at the time. The Oregon Health Sciences University name was modified to the Oregon Health & Science University. The merger was funded in part by a $4 million grant from the M.J. Murdock Charitable Trust, earmarked to help launch a new biomedical engineering program at the School. The OGI School of Science and Engineering was renamed the Department of Science & Engineering within the School of Medicine at OHSU in 2008. OHSU vacated the OGI campus in Hillsboro in 2014, and its programs were moved to the Marquam Hill complex. On October 29, 2008, OHSU announced its largest philanthropic gift up that time: a $100 million gift from Nike co-founder Phil Knight and his wife, Penny Knight. The gift went to the OHSU Cancer Institute, renaming it the OHSU Knight Cancer Institute. Five years later, in 2013, Knight announced his intention to donate an additional $500 million to OHSU specifically for cancer research if the university could match it over the subsequent two years. The challenge motivated Columbia Sportswear chairwoman Gert Boyle to donate $100 million in 2014. On June 25, 2015, OHSU met the $500 million matching-donations goal, and Knight met with Robin Roberts on Good Morning America that morning to announce his matching $500 million donation, bringing the total to $1 billion raised. OHSU remained Oregon's only medical school until 2011, when College of Osteopathic Medicine of the Pacific, Northwest opened in Lebanon, Oregon. The world's first in-vivo use of the Crispr-Cas9 DNA editing tool was conducted in 2020 at the Casey Eye Institute at OHSU. The procedure is intended to reverse a genetic mutation causing Leber congenital amaurosis, a form of inherited blindness. === Animal welfare violations === The United States Department of Agriculture cited OHSU in February 2020 for animal welfare violation after five prairie voles in its lab died of thirst. The violation followed a routine inspection in January 2020. The university was also cited for practices that risked contaminating surgical tools during procedures for probing a ferret's brain with an electrode. The university's ferret research was shut down for a month in 2019 after inspectors found three violations. These violations bring the number of serious violations at the university's animal lab to nine since 2014. == Campuses == The main campus, located on Marquam Hill (colloquially known as "Pill Hill") in the southwest neighborhood of Homestead, is home to the university's medical school as well as two associated hospitals. The Oregon Health & Science University Hospital is a Level I trauma center and general hospital; Doernbecher Children's Hospital is a children's hospital which specializes in pediatric medicine and care of children with long-term illness. The university maintains a number of outpatient primary care facilities including the Physician's Pavilion at the Marquam Hill campus as well as throughout the Portland metropolitan area. A third hospital, the Portland Veterans Affairs Medical Center is located next to the main OHSU campus; this hospital is run by the United States Department of Veterans Affairs and is outside the auspices of OHSU. A 660 feet (200 m) pedestrian skybridge connecting OHSU Hospital and the VA Medical Center was constructed in 1992. Additionally, the Portland Shriners Hospital for Children is located on the OHSU campus. The university also had a campus in Hillsboro, at the site of the former OGI. This campus specialized in graduate-level science and engineering education and is located in the heart of Oregon's Silicon Forest. Since 1998, the university has controlled the Oregon National Primate Research Center, located adjacent to OGI in Hillsboro.With the Marquam Hill campus running out of room for expansion, beginning in 2003 OHSU announced plans to expand into the South Waterfront District, formerly known as the North Macadam District. The expansion area is along the Willamette River in the South Portland neighborhood to the east of Marquam Hill and south of the city center. The Center for Health & Healing earned LEED Platinum certification in February 2007, becoming the largest health care center in the U.S. to achieve that status. As part of the continued expansion of the South Waterfront, on June 26, 2014, OHSU opened the Collaborative Life Sciences Building (CLSB). The building cost $295 million to construct, and houses OHSU School of Dentistry and Dental Clinics, Portland State University classes and Oregon State University's Doctor of Pharmacy program. In April, 2018, CLSB was renamed to the Joseph E. Robertson, Jr. Collaborative Life Sciences Building (RLSB). As existing surface streets were deemed insufficient to connect the South Waterfront campus to the Marquam Hill campus, the Portland Aerial Tram was built as the primary link between them and opened December 1, 2006. Controversy surrounded the costs of the tram, which nearly quadrupled from initial estimates. Construction of the tram was funded largely by OHSU ($40 million, 70%), with contributions from the city of Portland ($8.5 million, 15%) and developers and landowners in the South Portland neighborhood. On January 8, 2008, OHSU announced that it will establish a research institute at the Florida Center for Innovation at Tradition in the Tradition community in Port St. Lucie, Florida. The institute eventually will employ 200 workers. Institute scientists will study infectious diseases of the elderly, AIDS and other infectious diseases and viruses. OHSU will work out of the adjacent Torrey Pines Institute for Molecular Studies until its own center is completed. A $117.9 million financial incentive package from the state of Florida secured OHSU's commitment. == Academics == === School of Medicine === The OHSU School of Medicine has a faculty of approximately 1,750 and confers a variety of degrees, including Doctor of Medicine, Doctor of Philosophy, Master of Science, Master of Physician Assistant Studies, and Master of Public Health. In 2022, the U.S. News & World Report ranked OHSU 4th overall in Primary Care Rankings and 32nd in Research Rankings. In addition, the publication ranked the school 1st in Family Medicine. As one of only two medical schools in Oregon, and the only awarding a Doctor of Medicine degree (College of Osteopathic Medicine of the Pacific, Northwest located in Lebanon, Oregon awards a Doctor of Osteopathic Medicine degree and was established in 2011), OHSU is committed to meeting the health care needs of the state with typically 70% of the students from in-state. Admissions is highly competitive, with the school receiving over 6,700 applications and interviewing approximately 570 applicants for 150 seats. The average GPA of the entering class is 3.63 with a median MCAT score of 509. Its Physician Assistant program was most recently ranked 5th by U.S. News & World Report. === School of Dentistry === OHSU's School of Dentistry was merged into the university in 1945. Accredited through the Commission on Dental Accreditation, the school has departments in endodontics, orthodontics, pathology and radiology, oral and maxillofacial surgery, periodontics, and pediatric dentistry, among others. The D.M.D. program admits 75 students each year. In 2014, the School of Dentistry program moved to the Collaborative Life Sciences Building on Portland's South Waterfront along with the School of Medicine. === School of Nursing === The School of Nursing at OHSU offers nursing programs at the undergraduate, graduate, and doctoral levels. The graduate nursing program was most recently ranked 7th overall in the nation by the U.S. News & World Report and 5th in the gerontology/geriatric specialty. == OHSU Foundation == The Oregon Health & Science University Foundation is a 501(c)(3) organization that exists to advance OHSU's mission through philanthropy. The Doernbecher Children's Hospital Foundation merged with the OHSU Foundation in 2021. == Controversies == === Aerial tram === In 2001, OHSU purchased property in what is now known as the South Waterfront neighborhood with intentions to expand its facilities there. After the purchase, OHSU began developing plans with the Portland Office of Transportation to connect this location to its Marquam Hill facilities by way of an aerial tram. Before construction of the tram began in 2005, the project was criticized by residents in the neighborhoods located directly below the projected tram route who believed its construction would result in an invasion of privacy and lower property values. The group No Tram to OHSU argued that OHSU had not sufficiently justified the benefits of the tram, that the tram would not alleviate traffic congestion on Marquam Hill as OHSU claimed, and that the project inappropriately made use of public right of way for private purposes. During the construction phase, the project came under additional public scrutiny amid rising construction and operation costs. The final cost of its construction was $57 million, almost 4 times over its original projected budget. After opening in December 2006, the tram carried its one millionth passenger on October 17, 2007, and its ten millionth rider on January 8, 2014. === PETA === In 2006, the animal rights group PETA brought attention to OHSU research involving sheep. The research, which was being conducted in conjunction with Oregon State University was designed to understand the biological mechanisms involved in sexual partner preference. == Notable alumni and faculty == Esther Choo, Emergency physician, president of the Academy of Women in Academic Emergency Medicine Mustafa Culha, Chemistry professor, and research group founder Brian Druker, Physician, co-developer of Gleevec and director of the Knight Cancer Institute John Epley, Physician, developer of the Epley maneuver Suzanne Fei, Computational biologist, Bioinformatics & Biostatistics Core Director Catherine G Galbraith, expert in cell migration and super-resolution microscopy N. Gregory Hamilton, Psychiatrist Matthew Keeslar, Physician Assistant Instructor of Urology, School of Medicine. Former professional actor (Waiting for Guffman, Scream 3, Frank Herbert's Dune) Lena Kenin, OB/GYN, psychiatrist John Kitzhaber, Physician, longest-serving governor in Oregon's history Muriel Lezak, American neuropsychologist and author Owen McCarty, Chair of the Department of Biomedical Engineering Bita Moghaddam, Ruth Matarazzo Professor of Behavioral Neuroscience, author Bud Pierce, Physician and politician Lendon Smith, OB/GYN, pediatrician, author, and television personality Albert Starr First surgeon to implant a heart valve successfully. Kent L. Thornburg, scientist, researcher, professor Shoshana R. Ungerleider, Internal Medicine Physician, film producer Melissa Wong, Cancer stem cell biologist D. George Wyse, Expert in cardiac arrhythmias == See also == Art collection of Oregon Health & Science University Marquam Nature Park == References == == External links == Media related to Oregon Health & Science University at Wikimedia Commons Official website
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Christian Science is a set of beliefs and practices which are associated with members of the Church of Christ, Scientist. Adherents are commonly known as Christian Scientists or students of Christian Science, and the church is sometimes informally known as the Christian Science church. It was founded in 1879 in New England by Mary Baker Eddy, who wrote the 1875 book Science and Health with Key to the Scriptures, which outlined the theology of Christian Science. The book was originally called Science and Health; the subtitle with a Key to the Scriptures was added in 1883 and later amended to with Key to the Scriptures. The book became Christian Science's central text, along with the Bible, and by 2001 had sold over nine million copies. Eddy and 26 followers were granted a charter by the Commonwealth of Massachusetts in 1879 to found the "Church of Christ (Scientist)"; the church would be reorganized under the name "Church of Christ, Scientist" in 1892. The Mother Church, The First Church of Christ, Scientist, was built in Boston, Massachusetts, in 1894. Known as the "thinker's religion", Christian Science became the fastest growing religion in the United States, with nearly 270,000 members by 1936 — a figure which had declined to just over 100,000 by 1990 and reportedly to under 50,000 by 2009. The church is known for its newspaper, The Christian Science Monitor, which won seven Pulitzer Prizes between 1950 and 2002, and for its public Reading Rooms around the world. Christian Science's religious tenets differ considerably from many other Christian denominations, including key concepts such as the Trinity, the divinity of Jesus, atonement, the resurrection, and the Eucharist. Eddy, for her part, described Christian Science as a return to "primitive Christianity and its lost element of healing". Adherents subscribe to a radical form of philosophical idealism, believing that reality is purely spiritual and the material world an illusion. This includes the view that disease is a mental error rather than physical disorder, and that the sick should be treated not by medicine but by a form of prayer that seeks to correct the beliefs responsible for the illusion of ill health. The church does not require that Christian Scientists avoid medical care—many adherents use dentists, optometrists, obstetricians, physicians for broken bones, and vaccination when required by law—but maintains that Christian Science prayer is most effective when not combined with medicine. The reliance on prayer and avoidance of medical treatment has been blamed for the deaths of adherents and their children. Between the 1880s and 1990s, several parents and others were prosecuted for, and in a few cases convicted of, manslaughter or neglect. == Overview == === Metaphysical family === Several periods of Protestant Christian revival nurtured a proliferation of new religious movements in the United States. In the latter half of the 19th century, these included what came to be known as the metaphysical family: groups such as Christian Science, Divine Science, the Unity School of Christianity, and (later) the United Church of Religious Science. From the 1890s, the liberal section of the movement became known as New Thought, in part to distinguish it from the more authoritarian Christian Science. The term metaphysical referred to the movement's philosophical idealism, a belief in the primacy of the mental world. Adherents believed that material phenomena were the result of mental states, a view expressed as "life is consciousness" and "God is mind." The supreme cause was referred to as Divine Mind, Truth, God, Love, Life, Spirit, Principle or Father–Mother, reflecting elements of Plato, Hinduism, Berkeley, Hegel, Swedenborg, and transcendentalism. The metaphysical groups became known as the mind-cure movement because of their strong focus on healing. Medical practice was in its infancy, and patients regularly fared better without it. This provided fertile soil for the mind-cure groups, who argued that sickness was an absence of "right thinking" or failure to connect to Divine Mind. The movement traced its roots in the United States to Phineas Parkhurst Quimby (1802–1866), a New England clockmaker turned mental healer. His advertising flyer, "To the Sick" included this explanation of his clairvoyant methodology: "he gives no medicines and makes no outward applications, but simply sits down by the patients, tells them their feelings and what they think is their disease. If the patients admit that he tells them their feelings, &c., then his explanation is the cure; and, if he succeeds in correcting their error, he changes the fluids of the system and establishes the truth, or health. The Truth is the Cure. This mode of practise applies to all cases. If no explanation is given, no charge is made, for no effect is produced." Mary Baker Eddy had been a patient of his (1862–1865), leading to debate about how much of Christian Science was based on his ideas. New Thought and Christian Science differed in that Eddy saw her views as a unique and final revelation. Eddy's idea of malicious animal magnetism (that people can be harmed by the bad thoughts of others) marked another distinction, introducing an element of fear that was absent from the New Thought literature. Most significantly, she dismissed the material world as an illusion, rather than as merely subordinate to Mind, leading her to reject the use of medicine, or materia medica, and making Christian Science the most controversial of the metaphysical groups. Reality for Eddy was purely spiritual. === Christian Science theology === Christian Science leaders place their religion within mainstream Christian teaching, according to J. Gordon Melton, and reject any identification with the New Thought movement. Eddy was strongly influenced by her Congregationalist upbringing. According to the church's tenets, adherents accept "the inspired Word of the Bible as [their] sufficient guide to eternal Life ... acknowledge and adore one supreme and infinite God ... [and] acknowledge His Son, one Christ; the Holy Ghost or divine Comforter; and man in God's image and likeness." When founding the Church of Christ, Scientist, in April 1879, Eddy wrote that she wanted to "reinstate primitive Christianity and its lost element of healing". Later she suggested that Christian Science was a kind of second coming and that Science and Health was an inspired text. In 1895, in the Manual of the Mother Church, she ordained the Bible and Science and Health as "Pastor over the Mother Church". Christian Science theology differs in several respects from that of traditional Christianity. Eddy's Science and Health reinterprets key Christian concepts, including the Trinity, divinity of Jesus, atonement, and resurrection; beginning with the 1883 edition, she added "with a Key to the Scriptures" to the title and included a glossary that redefined the Christian vocabulary. At the core of Eddy's theology is the view that the spiritual world is the only reality and is entirely good, and that the material world, with its evil, sickness and death, is an illusion. Eddy saw humanity as an "idea of Mind" that is "perfect, eternal, unlimited, and reflects the divine", according to Bryan Wilson; what she called "mortal man" is simply humanity's distorted view of itself. Despite her view of the non-existence of evil, an important element of Christian Science theology is that evil thought, in the form of malicious animal magnetism, can cause harm, even if the harm is only apparent. Eddy viewed God not as a person but as "All-in-all". Although she often described God in the language of personhood—she used the term "Father–Mother God" (as did Ann Lee, the founder of Shakerism), and, in the third edition of Science and Health, she referred to God as "she"—God is mostly represented in Christian Science by the synonyms "Mind, Spirit, Soul, Principle, Life, Truth, Love". The Holy Ghost is Christian Science, and heaven and hell are states of mind. There is no supplication in Christian Science prayer. The process involves the Scientist engaging in a silent argument to affirm to herself the unreality of matter, something Christian Science practitioners will do for a fee, including in absentia, to address ill health or other problems. Wilson writes that Christian Science healing is "not curative ... on its own premises, but rather preventative of ill health, accident and misfortune, since it claims to lead to a state of consciousness where these things do not exist. What heals is the realization that there is nothing really to heal." It is a closed system of thought, viewed as infallible if performed correctly; healing confirms the power of Truth, but its absence derives from the failure, specifically the bad thoughts, of individuals. Eddy accepted as true the creation narrative in the Book of Genesis up to chapter 2, verse 6—that God created man in his image and likeness—but she rejected the rest "as the story of the false and the material", according to Wilson. Her theology is nontrinitarian: she viewed the Trinity as suggestive of polytheism. She saw Jesus as a Christian Scientist, a "Way-shower" between humanity and God, and she distinguished between Jesus the man and the concept of Christ, the latter a synonym for Truth and Jesus the first person fully to manifest it. The crucifixion was not a divine sacrifice for the sins of humanity, the atonement (the forgiveness of sin through Jesus's suffering) "not the bribing of God by offerings", writes Wilson, but an "at-one-ment" with God. Her views on life after death were vague and, according to Wilson, "there is no doctrine of the soul" in Christian Science: "[A]fter death, the individual continues his probationary state until he has worked out his own salvation by proving the truths of Christian Science." Eddy did not believe that the dead and living could communicate. To the more conservative of the Protestant clergy, Eddy's view of Science and Health as divinely inspired was a challenge to the Bible's authority. "Eddyism" was viewed as a cult; one of the first uses of the modern sense of the word was in A. H. Barrington's Anti-Christian Cults (1898), a book about Spiritualism, Theosophy and Christian Science. In a few cases Christian Scientists were expelled from Christian congregations, but ministers also worried that their parishioners were choosing to leave. In May 1885 the London Times' Boston correspondent wrote about the "Boston mind-cure craze": "Scores of the most valued Church members are joining the Christian Scientist branch of the metaphysical organization, and it has thus far been impossible to check the defection." In 1907 Mark Twain described the appeal of the new religion to its adherents: [Mrs. Eddy] has delivered to them a religion which has revolutionized their lives, banished the glooms that shadowed them, and filled them and flooded them with sunshine and gladness and peace; a religion which has no hell; a religion whose heaven is not put off to another time, with a break and a gulf between, but begins here and now, and melts into eternity as fancies of the waking day melt into the dreams of sleep. They believe it is a Christianity that is in the New Testament; that it has always been there, that in the drift of ages it was lost through disuse and neglect, and that this benefactor has found it and given it back to men, turning the night of life into day, its terrors into myths, its lamentations into songs of emancipation and rejoicing. There we have Mrs. Eddy as her followers see her. ... They sincerely believe that Mrs. Eddy's character is pure and perfect and beautiful, and her history without stain or blot or blemish. But that does not settle it. == History == === Mary Baker Eddy and the early Christian Science movement === Mary Baker Eddy was born Mary Morse Baker on a farm in Bow, New Hampshire, the youngest of six children in a religious family of Protestant Congregationalists. In common with most women at the time, Eddy was given little formal education, but read widely at home and was privately tutored. From childhood, she lived with protracted ill health. Eddy's first husband died six months after their marriage and three months before their son was born, leaving her penniless; and as a result of her poor health she lost custody of the boy when he was four. She married again, and her new husband promised to become the child's legal guardian, but after their marriage he refused to sign the needed papers and the boy was taken to Minnesota and told his mother had died. Eddy, then known as Mary Patterson, and her husband moved to rural New Hampshire, where Eddy continued to suffer from health problems which often kept her bedridden. Eddy tried various cures for her health problems, including conventional medicine as well as many forms of alternative medicine such as Grahamism, electrotherapy, homeopathy, hydropathy, and finally mesmerism under Phineas Quimby. She was later accused by critics, beginning with Julius Dresser, of borrowing ideas from Quimby in what biographer Gillian Gill would call the "single most controversial issue" of her life. In February 1866, Eddy fell on the ice in Lynn, Massachusetts. Evidence suggests she had severe injuries, but a few days later she apparently asked for her Bible, opened it to an account of one of Jesus' miracles, and left her bed telling her friends that she was healed through prayer alone. The moment has since been controversial, but she considered this moment one of the "falling apples" that helped her to understand Christian Science, although she said she did not fully understand it at the time. In 1866, after her fall on the ice, Eddy began teaching her first student and began writing her ideas which she eventually published in Science and Health with Key to the Scriptures, considered her most important work. Her students voted to form a church called the Church of Christ (Scientist) in 1879, later reorganized as The First Church of Christ, Scientist, also known as The Mother Church, in 1892. She founded the Massachusetts Metaphysical College in 1881 to continue teaching students, Eddy started a number of periodicals: The Christian Science Journal in 1883, the Christian Science Sentinel in 1898, The Herald of Christian Science in 1903, and The Christian Science Monitor in 1908, the latter being a secular newspaper. The Monitor has gone on to win seven Pulitzer prizes as of 2011. She also wrote numerous books and articles in addition to Science and Health, including the Manual of The Mother Church which contained by-laws for church government and member activity, and founded the Christian Science Publishing Society in 1898 in order to distribute Christian Science literature. Although the movement started in Boston, the first purpose-built Christian Science church building was erected in 1886 in Oconto, Wisconsin. During Eddy's lifetime, Christian Science spread throughout the United States and to other parts of the world including Canada, Great Britain, Germany, South Africa, Hong Kong, the Philippines, Australia, and elsewhere. Eddy encountered significant opposition after she began teaching and writing on Christian Science, which only increased towards the end of her life. One of the most prominent examples was Mark Twain, who wrote a number of articles on Eddy and Christian Science which were first published in Cosmopolitan magazine in 1899 and were later published as a book. Another extended criticism, which again was first serialized in a magazine and then published in book form, was Georgine Milmine and Willa Cather's The Life of Mary Baker G. Eddy and the History of Christian Science which first appeared in McClure's magazine in January 1907. Also in 1907, several of Eddy's relatives filed an unsuccessful lawsuit instigated by the New York World, known in the press as the "Next Friends Suit", against members of Eddy's household, alleging that she was mentally unable to manage her own affairs. The suit fell apart after Eddy was interviewed in her home in August 1907 by the judge and two court-appointed masters (one a psychiatrist) who concluded that she was mentally competent. Separately, she was seen by two psychiatrists, including Allan McLane Hamilton, who came to the same conclusion. The McClure's and New York World stories are considered to at least partially be the reason Eddy asked the church in July 1908 to found the Christian Science Monitor as a platform for responsible journalism. Eddy died two years later, on the evening of Saturday, December 3, 1910, aged 89. The Mother Church announced at the end of the Sunday morning service that Eddy had "passed from our sight". The church stated that "the time will come when there will be no more death," but that Christian Scientists "do not look for [Eddy's] return in this world." Her estate was valued at $1.5 million, most of which she left to the church. === The Christian Science movement after 1910 === In the aftermath of Eddy's death, some newspapers speculated that the church would fall apart, while others expected it to continue just as it had before. As it was, the movement continued to grow in the first few decades after 1910. The Manual of the Mother Church prohibits the church from publishing membership figures, and it is not clear exactly when the height of the movement was. A 1936 census counted c. 268,915 Christian Scientists in the United States (2,098 per million), and Rodney Stark believes this to be close to the height. However, the number of Christian Science churches continued to increase until around 1960, at which point there was a reversal and, since then, many churches have closed their doors. The number of Christian Science practitioners in the United States began to decline in the 1940s according to Stark. According to J. Gordon Melton, in 1972 there were 3,237 congregations worldwide, of which roughly 2,400 were in the United States; and, in the following ten years, about 200 congregations were closed. During the years after Eddy's death, the church has gone through a number of hardships and controversies. This included attempts to make practicing Christian Science illegal in the United States and elsewhere; a period known as the Great Litigation which involved two intertwined lawsuits regarding church governance; persecution under the Nazi and Communist regimes in Germany and the Imperial regime in Japan; a series of lawsuits involving the deaths of members of the church, most notably some children; and a controversial decision to publish a book by Bliss Knapp. In conjunction with the Knapp book controversy, there was controversy within the church involving The Monitor Channel, part of The Christian Science Monitor which had been losing money, and which eventually led to the channel shutting down. Acknowledging their earlier mistake, of accepting a multi-million dollar publishing incentive to offset broadcasting losses, The Christian Science Board Of Directors, with the concurrence of the Trustees Of The Christian Science Publishing Society, withdrew Destiny Of The Mother Church from publication in September 2023. In addition, it has since its beginning been branded as a cult by more fundamentalist strains of Christianity, and attracted significant opposition as a result. A number of independent teachers and alternative movements of Christian Science have emerged since its founding, but none of these individuals or groups have achieved the prominence of the Christian Science church. Despite the hardships and controversies, many Christian Science churches and Reading Rooms remain in existence around the world, and, in recent years, there have been reports of the religion growing in Africa, though it remains significantly behind other evangelical groups. The Christian Science Monitor also remains a well-respected non-religious paper which is especially noted for its international reporting and lack of partisanship. == Healing practices == === Christian Science prayer === [A]ll healing is a metaphysical process. That means that there is no person to be healed, no material body, no patient, no matter, no illness, no one to heal, no substance, no person, no thing and no place that needs to be influenced. This is what the practitioner must first be clear about. Christian Scientists avoid almost all medical treatment, relying instead on Christian Science prayer. This consists of silently arguing with oneself; there are no appeals to a personal god, and no set words. Caroline Fraser wrote in 1999 that the practitioner might repeat: "the allness of God using Eddy's seven synonyms—Life, Truth, Love, Spirit, Soul, Principle and Mind," then that "Spirit, Substance, is the only Mind, and man is its image and likeness; that Mind is intelligence; that Spirit is substance; that Love is wholeness; that Life, Truth, and Love are the only reality." She might deny other religions, the existence of evil, mesmerism, astrology, numerology, and the symptoms of whatever the illness is. She concludes, Fraser writes, by asserting that disease is a lie, that this is the word of God, and that it has the power to heal. Christian Science practitioners are certified by the Church of Christ, Scientist, to charge a fee for Christian Science prayer. There were 1,249 practitioners worldwide in 2015; in the United States in 2010 they charged $25–$50 for an e-mail, telephone or face-to-face consultation. Their training is a two-week, 12-lesson course called "primary class", based on the Recapitulation chapter of Science and Health. Practitioners wanting to teach primary class take a six-day "normal class", held in Boston once every three years, and become Christian Science teachers. There are also Christian Science nursing homes. They offer no medical services; the nurses are Christian Scientists who have completed a course of religious study and training in basic skills, such as feeding and bathing. The Christian Science Journal and Christian Science Sentinel publish anecdotal healing testimonials (they published 53,900 between 1900 and April 1989), which must be accompanied by statements from three verifiers: "people who know [the testifier] well and have either witnessed the healing or can vouch for [the testifier's] integrity in sharing it". Philosopher Margaret P. Battin wrote in 1999 that the seriousness with which these testimonials are treated by Christian Scientists ignores factors such as false positives caused by self-limiting conditions. Because no negative accounts are published, the testimonials strengthen people's tendency to rely on anecdotes. A church study published in 1989 examined 10,000 published testimonials, 2,337 of which the church said involved conditions that had been medically diagnosed, and 623 of which were "medically confirmed by follow-up examinations". The report offered no evidence of the medical follow-up. The Massachusetts Committee for Children and Youth listed among the report's flaws that it had failed to compare the rates of successful and unsuccessful Christian Science treatment. Nathan Talbot, a church spokesperson, told the New England Journal of Medicine in 1983 that church members were free to choose medical care, but according to former Christian Scientists those who do may be ostracized. In 2010 the New York Times reported church leaders as saying that, for over a year, they had been "encouraging members to see a physician if they feel it is necessary", and that they were repositioning Christian Science prayer as a supplement to medical care, rather than a substitute. The church has lobbied to have the work of Christian Science practitioners covered by insurance. As of 2015, it was reported that Christian Scientists in Australia were not advising anyone against vaccines, and the religious exception was deemed "no longer current or necessary". In 2021, a church Committee on Publication reiterated that although vaccination was an individual choice, that the church did not dictate against it, and those who were not vaccinated did not do so because of any "church dogma". == Church of Christ, Scientist == === Governance === In the hierarchy of the Church of Christ, Scientist, only the Mother Church in Boston, The First Church of Christ, Scientist, uses the definite article in its name. Otherwise the first Christian Science church in any city is called First Church of Christ, Scientist, then Second Church of Christ, Scientist, and so on, followed by the name of the city (for example, Third Church of Christ, Scientist, London). When a church closes, the others in that city are not renamed. Founded in April 1879, the Church of Christ, Scientist is led by a president and five-person board of directors. There is a public-relations department, known as the Committee on Publication, with representatives around the world; this was set up by Eddy in 1898 to protect her own and the church's reputation. The church was accused in the 1990s of silencing internal criticism by firing staff, delisting practitioners and excommunicating members. The church's administration is headquartered on Christian Science Center on the corner of Massachusetts Avenue and Huntington Avenue, located on several acres in the Back Bay section of Boston. The 14.5-acre site includes the Mother Church (1894), Mother Church Extension (1906), the Christian Science Publishing Society building (1934)—which houses the Mary Baker Eddy Library and the church's administrative staff—the Sunday School building (1971), and the Church Colonnade building (1972). It also includes the 26-story Administration Building (1972), designed by Araldo Cossutta of I. M. Pei & Associates, which until 2008 housed the administrative staff from the church's 15 departments. There is also a children's fountain and a 690 ft × 100 ft (210 m × 30 m) reflecting pool. === Manual of The Mother Church === Eddy's Manual of The Mother Church (first published 1895) lists the church's by-laws. Requirements for members include daily prayer and daily study of the Bible and Science and Health. Members must subscribe to church periodicals if they can afford to, and pay an annual tax to the church of not less than one dollar. Prohibitions include engaging in mental malpractice; visiting a store that sells "obnoxious" books; joining other churches; publishing articles that are uncharitable toward religion, medicine, the courts or the law; and publishing the number of church members. The manual also prohibits engaging in public debate about Christian Science without board approval, and learning hypnotism. It includes "The Golden Rule": "A member of The Mother Church shall not haunt Mrs. Eddy's drive when she goes out, continually stroll by her house, or make a summer resort near her for such a purpose." === Services === The Church of Christ, Scientist is a lay church which has no ordained clergy or rituals, and performs no baptisms; with clergy of other faiths often performing marriage or funeral services since they have no clergy of their own. Its main religious texts are the Bible and Science and Health. Each church has two Readers, who read aloud a "Bible lesson" or "lesson sermon" made up of selections from those texts during the Sunday service, and a shorter set of readings to open Wednesday evening testimony meetings. In addition to readings, members offer testimonials during the main portion of the Wednesday meetings, including recovery from ill health attributed to prayer. There are also hymns, time for silent prayer, and repeating together the Lord's Prayer at each service. === Notable members === Notable adherents of Christian Science have included Directors of Central Intelligence William H. Webster and Admiral Stansfield M. Turner; and Richard Nixon's chief of staff H. R. Haldeman and Chief Domestic Advisor John Ehrlichman. The viscounts Waldorf and Nancy Astor, the latter of whom was the first female member of British Parliament, were both Christian Scientists; as were two other early women in Parliament, Thelma Cazalet-Keir and Margaret Wintringham. Thelma's brother Victor Cazalet was also a member of the church. Another was naval officer Charles Lightoller, who survived the sinking of the Titanic in 1912. Other adherents in the United States government also include Senator Jocelyn Burdick, Governor Scott McCallum, and Treasury Secretary Henry Paulson. A number of suffragists were Christian Scientists including Vida Goldstein, Muriel Matters, and Nettie Rogers Shuler. Businesswomen Martha Matilda Harper and Bette Nesmith Graham were both Christian Scientists. As was the founder of the Braille Institute of America, J. Robert Atkinson. In sports, Harry Porter, Harold Bradley Jr., and George Sisler were all adherents. Christian Scientists within the film industry, include Carol Channing and Jean Stapleton; Colleen Dewhurst; Joan Crawford, Doris Day, George Hamilton, Mary Pickford, Ginger Rogers, Mickey Rooney; Horton Foote; King Vidor; Robert Duvall, and Val Kilmer. Those raised by Christian Scientists include jurist Helmuth James Graf von Moltke, military analyst Daniel Ellsberg; Ellen DeGeneres, Henry Fonda, Audrey Hepburn; James Hetfield, Marilyn Monroe, Robin Williams, Elizabeth Taylor, and Anne Archer. Four prominent African American entertainers who have been associated with Christian Science are Pearl Bailey, Lionel Hampton, Everett Lee, and Alfre Woodard. === Christian Science Publishing Society === The Christian Science Publishing Society publishes several periodicals, including the Christian Science Monitor, winner of seven Pulitzer Prizes between 1950 and 2002. This had a daily circulation in 1970 of 220,000, which by 2008 had contracted to 52,000. In 2009 it moved to a largely online presence with a weekly print run. In the 1980s the church produced its own television programs, and in 1991 it founded a 24-hour news channel, which closed with heavy losses after 13 months. The church also publishes the weekly Christian Science Sentinel, the monthly Christian Science Journal, and the Herald of Christian Science, a non-English publication. In April 2012 JSH-Online made back issues of the Journal, Sentinel and Herald available online to subscribers. === Works by Mary Baker Eddy === == See also == Affirmative prayer – form of prayer that focuses on a positive outcomePages displaying wikidata descriptions as a fallback Faith healing – Prayer and gestures perceived to bring divine intervention in physical healing New religious movement – Religious community or spiritual group of modern origin New Thought – 19th-century American spiritual movement Principia College – Private liberal arts college in Elsah, Illinois, U.S. Therapeutic nihilism – View that medical treatment is futile Third Great Awakening – Period of religious activism in American history == Citations == === Notes === === References === === Sources === Bates, Ernest S.; Dittemore, John V. (1932). Mary Baker Eddy: The Truth and the Tradition. New York: A. A. Knopf. Beasley, Norman (1956). The Continuing Spirit. New York: Duell, Sloan & Pearce. Fraser, Caroline (1999). God's Perfect Child. New York: Henry Holt & Co. Fuller, Linda K. (2011). The Christian Science Monitor: An Evolving Experiment in Journalism. ABC-CLIO. ISBN 978-0-31337994-9. Archived from the original on 2022-11-01. Gardner, Martin (August 22, 1999). "Mind Over Matter". Los Angeles Times. Gill, Gillian (1998). Mary Baker Eddy. Reading, MA: Perseus Books. ISBN 978-0-73820042-2. Gottschalk, Stephen (2006). Rolling Away the Stone: Mary Baker Eddy's Challenge to Materialism. Bloomington, IN: Indiana University Press. Knee, Stuart E. (1994). Christian Science in the Age of Mary Baker Eddy. Westport, CT: Greenwood Publishing Co. ISBN 978-0-31328360-4. Koestler-Grack, Rachel A. (2004). Mary Baker Eddy. Philadelphia: Chelsea House Publishers. ISBN 978-0-79107866-2. Margolick, David (August 6, 1990). "In Child Deaths, a Test for Christian Science". The New York Times. Melton, J. Gordon (1992). Encyclopedic Handbook of Cults in America. New York: Garland Pub. Milmine, Georgine; Cather, Willa (1909). The Life of Mary Baker G. Eddy and the History of Christian Science. New York: Doubleday. Peel, Robert (1971). Mary Baker Eddy: The Years of Trial. New York: Holt, Rinehart and Winston. ISBN 9780030867002. Voorhees, Amy B. (2021). A New Christian Identity: Christian Science Origins and Experience in American Culture. Chapel Hill, NC: University of North Carolina Press. == Further reading == Church histories (chronological) Books by former Christian Scientists == External links == Plainfield Christian Science Church, Independent—A part of the Christian Science movement, independent from the Mother Church in Boston
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Maxar Technologies Inc. is an American space technology company headquartered in Westminster, Colorado, United States, specializing in geospatial intelligence, Earth observation, and on-orbit servicing satellites, satellite products, and related services. DigitalGlobe and MDA Holdings Company merged to become Maxar Technologies on October 5, 2017. Maxar Technologies is the parent holding company of Maxar Space Systems, headquartered in Palo Alto, California, US; and Maxar Intelligence, headquartered in Westminster, Colorado, US. From 2017 to 2023, it was dual-listed on the Toronto Stock Exchange and New York Stock Exchange as MAXR. In May 2023, Maxar was acquired by private equity firm Advent International, in an all-cash transaction worth $6.4 billion. Maxar's satellite data was used by Ukraine as part of its defense against Russia's invasion of its territory. In March 2025, Maxar worked with the Donald Trump administration to shut down Ukraine's access to the data. == History == Maxar Technologies was created in 2017 from the purchase of DigitalGlobe by MacDonald, Dettwiler and Associates (MDA), who renamed the company Maxar. The headquarters of the combined entity was then established in Westminster, Colorado. The company was dual-listed on the TSX and NYSE. In Q3 2018 Maxar's revenue and adjusted profit missed estimates due to a decline in its satellite manufacturing segment oriented towards geosynchronous Earth orbit communications, which led to a plunge in the stock price. The situation was compounded in January 2019 with the loss of their relatively new WorldView-4 satellite, and the market capitalization fell from $3 to $0.3 billion in half a year, and with an insurance payment only covering a fifth of WV-4 total launch cost the company had to restructure its debts in April 2019. In May 2019, the company was selected as the provider of the power and propulsion element for the Lunar Gateway developed by NASA. On December 30, 2019, the company announced that it had entered into a definitive agreement to sell MDA's assets to a consortium of financial sponsors led by Northern Private Capital for CA$1 billion (US$765 million). The sale includes all of MDA's Canadian businesses, encompassing ground stations, radar satellite products, robotics, defense, and satellite components, representing approximately 1,900 employees. On April 8, 2020, the sale of MDA to NPC officially closed. The divesting of its Canadian MDA portion returned MDA to a separate operating company. The newly formed privately held Canadian company was named MDA Ltd., which later listed on the Toronto Stock Exchange. In 2022, Maxar published several satellite images that showed a Russian military convoy during its invasion of Ukraine. In September 2023, Maxar was broken into two business units, Maxar Space Systems (based in California, led by CEO Chris Johnson) and Maxar Intelligence (based in Colorado, led by CEO Dan Smoot). In early March 2025, Maxar Technologies suspended Ukraine's access to its satellite imagery, stating that the request came from the Trump administration. Maxar had been a leading provider of satellite data to Ukraine, which the country used as part of its efforts to defend itself against the Russian invasion. The data was used to track the movement of Russian troops and assess damage to Ukrainian infrastructure. === Controversy over BSI Partnership and Pahalgam Imagery Orders (2025) === In May 2025, Maxar Technologies faced scrutiny following reports that it had received an unusual spike in orders for high-resolution satellite images of Pahalgam, a region in Jammu and Kashmir, India. Between February 2 and 22, 2025, at least 12 such orders were placed, which was double the usual number. This surge occurred shortly after Maxar partnered with Business Systems International Pvt Ltd (BSI), a Pakistani geospatial firm. BSI is owned by Obaidullah Syed, a Pakistani-American businessman who was convicted in 2021 for illegally exporting high-performance computing equipment and software to Pakistan's nuclear research agency. Despite this conviction, BSI was listed as a Maxar partner in 2023. Following the revelations about the satellite imagery orders, Maxar removed BSI from its list of partners on its website. Maxar stated that BSI had not placed any orders for imagery of Pahalgam or its surrounding areas in 2025 and had not accessed any such imagery from its archives. However, the timing of the imagery orders and BSI's partnership raised concerns among defense analysts and experts. In May 2025, it was further reported that the U.S. Department of Homeland Security had earlier complained that BSI had sold satellite imagery to an arm of the Pakistani government. This raised additional concerns about the firm’s access to sensitive geospatial data and its ties to Maxar Technologies. === Timeline === 1969: John MacDonald and Vern Dettwiler founded MacDonald, Dettwiler and Associates. 1993: MDA sells its Electro-Optical Division (EOP) based in Richmond Canada to a Swiss Private Equity firm which merges with Cymbolic Sciences based in California. 1995: MDA was acquired by Orbital Sciences for $67 million in stock 1996: acquired Iotek, a supplier of signal processing and sonar technology for military customers, for undisclosed sum 2000: entered joint venture with LandAmerica Financial Group to create LandMDA, a provider of property reports to lenders 2000/01: Orbital Sciences divested its MDA shares through an initial public offering; trades as TSX: MDA 2002: acquired Automated Mining Systems of Aurora, Ontario for $225,000 2002: acquired Dynacs for $3.1 million, with an additional $6.8 million contingent on performance (now "MDA US Systems, LLC", located in Houston, Texas) 2003: acquired Millar & Bryce, a commercial provider of land information in Scotland, for $21.32 million, with $1.76 million contingent on performance. 2004: acquired Marshall & Swift / Boeckh for $337.8 million, with $104.9 million contingent on performance. 2005: acquired business of EMS Technologies Canada (previously RCA Canada, which then became the Montreal division of SPAR Aerospace), a major supplier and subcontractor, for $8.9 million 2006: expanded into financial services with acquisition of Mindbox, a supplier of advanced decision systems for mortgage lending, for US$12.6 million, with up to $10.75 million contingent on performance 2006: acquired xit2 Ltd. (Nr Charlbury, Oxfordshire, UK), information exchange solutions for lenders and home surveyors and other outsourced service providers 2006: acquired Lyttle & Co. (Belfast, Northern Ireland), property and related search information 2007: acquired Alliance Spacesystems, Inc. (now "Maxar Space Robotics LLC", located in Pasadena, CA, US) 2008: MDA announced the sale of its Information Systems and Geospatial Services operations to Alliant Techsystems of Edina, Minnesota for $1.325 billion. However, amongst much media coverage, the sale was rejected by the federal government of Canada under the Investment Canada Act. 2008: Canadian government officially blocked the sale of MDA to ATK on May 8, 2008 2012: acquired Space Systems/Loral for US$875 million, making MDA one of the world's leading communication satellite companies. 2014: acquired the Advanced Systems business line (formerly ERIM International) of General Dynamics Advanced Information Systems division. 2017: Completed its acquisition of DigitalGlobe, MDA now will be named Maxar Technologies, dual-listed on NYSE and TSX. MDA will then be a subsidiary of US-based Maxar by 2019. 2018: Announced acquisition of Neptec for $32 million. 2019: Completed U.S. domestication, changing the parent company's incorporation from Canada to Delaware, USA. 2020: MDA is sold to a consortium of Canadian investors led by Northern Private Capital. This sale includes the Houston-based MDA US Systems, LLC. 2020: Completed its acquisition of Vricon, Inc for $140 million. Vricon is a global leader in satellite-derived 3D data for defense and intelligence markets 2022: Maxar to be taken private through an acquisition led by Advent International, in a cash deal worth $6.4 billion. The acquisition completed in May 2023. 2024: Maxar Intelligence launches WorldView Legion a fleet of six high-performing satellites that dramatically expanded the ability to revisit the most rapidly changing areas on Earth, enabling more near-time insights. 2025: Maxar shuts down access to satellite images in Ukraine following request from the Trump administration. 2025: Came under scrutiny for Pahalgam imagery orders and prior partnership with BSI, a Pakistani firm flagged by U.S. Homeland Security for selling satellite data to Pakistan’s government. == See also == Bombardier Aerospace COM DEV International CMC Electronics Héroux-Devtek MDA Space Missions Spar Aerospace Viking Air == References == == External links == Official website
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N.Technology is an Italian motor racing team, founded by Mauro Sipsz and Monica Bregoli. == Team history == N.Technology (originally named Nordauto Squadra Corse or Team Nordauto) were set up to manage the worldwide sporting activities of the Fiat Group. In 1994 the name was changed to Nordauto Engineering and in 2001 to N.Technology. === Touring cars === This included designing, building and running the Alfa Romeo 156 for use in touring cars. N.Technology won seven European and five Italian Championships with Alfa Romeo, winning three consecutive European Touring Car Championship drivers' titles, with Fabrizio Giovanardi in 2001 and 2002 and with Gabriele Tarquini in 2003. The team continued to run in the World Touring Car Championship, with Fabrizio Giovanardi finishing third in 2005. In 2006 they went it alone without support from Alfa Romeo, running Augusto Farfus to third in the standings. James Thompson also finished third for the team in 2007. The team ran a Honda Accord Euro R for Thompson in 2008, but with less success. === Rallying === N.Technology ran Fiat's entry in the inaugural season of the Intercontinental Rally Challenge, with driver Giandomenico Basso winning the championship with a Fiat Punto Abarth S2000 in 2006. === Formula Master === N.Technology created the International Formula Master series, which began in 2007. === Superstars === In 2010, N. Technology built and ran a Porsche Panamera for touring car specialist, Fabrizio Giovanardi. === Formula One application === In 2009, N.Technology's parent company, MSC Organization Ltd, submitted an application under the N.Technology banner to join the 2010 Formula One World Championship. The team stated that it had deals in place with potential partners should its application be successful. The list of entrants for the 2010 Formula One World Championship season did not include N.Technology when it was posted on 12 June. On 19 June it was revealed that N.Technology had withdrawn its application to enter F1 because it did not want to be involved without major manufacturers, following FOTA's proposals to form a breakaway series. == References ==
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https://en.wikipedia.org/wiki/N.Technology
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Qatar Science & Technology Park (QSTP) is a home for international technology companies in Qatar, and an incubator of start-up technology businesses. Inaugurated in March 2009 as a part of Qatar Foundation, the purpose of the science park is to spur development of Qatar's knowledge economy. At an investment of more than $800 million by Qatar Foundation, the QSTP also became Qatar's first free-trade zone. == Facilities and Functions == The QSTP complex was designed by Australian architects Woods Bagot, who won the Australian Institute of Architects National Award for their design. QSTP functions by providing office and lab space to tenant companies, in a complex of multi-user and single-user buildings, and by providing professional services and support programs to those companies, such as the flagship QSTP XLR8, a tech business accelerator program. In September 2005 the Government of Qatar passed a law making the science park a "free zone", allowing foreign companies to set up a 100 percent owned entity free from tax and duties. === Management and Operations === QSTP has a staff of 1000 which includes all individuals that work at the science park for the QSTP entities, as well QSTP management. == Collaboration and Ecosystem == A feature of QSTP is that it is co-located at Qatar Foundation's Education City alongside international universities. These include Carnegie Mellon, Cornell, Georgetown, Northwestern, Texas A&M and Virginia Commonwealth. The science park helps its tenant companies to collaborate with the universities, and acts as an incubator for spin-out ventures from the universities (and other sources). === Tenant Companies and Requirements === Tenants of QSTP are required to make technology development their main activity but can also trade commercially. The first companies to join QSTP were EADS, ExxonMobil, GE, Microsoft, Rolls-Royce, Shell, Total and iHorizons. == Goals and Objectives == QSTP aims to grow Qatar's knowledge economy by encouraging companies and institutes from around the world to develop and commercialise their technology in these sectors in Qatar. In addition, to have a big responsibility and commitment to develop the role of Qataris themselves in the R&D technology sector and this includes providing high tech training, supporting new business startups and enhancing technology management skills. The move towards a knowledge based society requires focus and this is how it is structured for the coming years ahead. The second stage of development began in 2013, with one new facility being completed in 2014, and another in 2016. === International Recognition and Impact === QSTP is a member of the International Association of Science Parks and Areas of Innovation, an NGO in special consultative status with the UN, and in 2014 was the first Arab country to host the association's 31st World Conference. == References == == External links == Official website
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https://en.wikipedia.org/wiki/Qatar_Science_&_Technology_Park
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Property technology (also known as by the portmanteaus proptech, PropTech, prop-tech and also known as real estate technology) is used to refer to the application of information technology and platform economics to the real estate industry. Property technology overlaps with financial technology, including uses like online payment and booking systems. == Overview == Property technology encompasses any application of digital technology or platform economics in the real estate industry. Some examples of property technology include property management using digital dashboards, smart home technology, research and analytics, listing services/tech-enabled brokerages, mobile applications, residential and commercial lending, 3D-modeling for online portals, automation, crowdfunding real estate projects, shared spaces management, as well as organizing, analyzing, and extracting key data from lengthy rental documents. According to economist Richard Reed, the real estate industry has historically been conservative in its approach to technology, and is slower to adopt new technologies than other industries. Advances in the residential side of real estate technology encompass some target areas, but generally aim to reduce friction in the purchase, sale, or rental of a property. Areas of focus include finding a home, selling a home, financing a purchase, closing on a property (including valuation, title & escrow, and title insurance), managing a property, managing loans, and mortgage lending software. Many proptech companies have seen a spike in demand for these solutions as the COVID-19 pandemic has jolted management companies from their "business as usual" routine. == History of real estate technology == The history of property technology is often divided into three stages of development. These stages broadly correspond to the period from 1980 to 2000, from 2000 to 2008, and from 2008 to the present. Digital technology began to be adopted by the real estate industry during the 1980s, when personal computing became more common. Spreadsheet and accounting software like Microsoft Excel began to be used by real estate companies when they were first introduced. Advancements in the area of investment analysis also allowed real estate investors to more accurately assess the value of commercial real estate using larger databases of information. The second stage began as real estate technology first targeted consumers during the dot-com bubble. At a time when most sales and residential listings were on print media and real estate offices, companies began to focus on moving listings onto the digital media. From 2008 onwards, the widespread availability of high speed internet meant that real estate companies could move more of their data and services online. Real estate databases such as Zillow are an example of information such as geographic data, property valuation and real estate advice being moved online. This has been successful, with companies like Zillow (US), Rightmove (UK),PriceHubble (CH) and Aurum PropTech (India) being in the top listed companies in their respective markets. The rise of digital technology during the 21st century has led to the development of a sharing economy, where applications such as ridesharing platforms became common. This also extended to real estate, as websites such as Airbnb and WeWork made it possible for property owners to rent out their property for part of the year. The COVID-19 accelerated the adoption of information technology in the real estate industry. The pandemic helped to drive e-commerce and resulted in the closure of many traditional retail stores, which has impacted the commercial real estate industry. Blockchain technology has also been used to track property for the purposes of land registration and resolve potential ownership disputes. Post pandemic, proptech is increasingly influenced by wider societal concerns, such as town planning, and public sector applications. An example of this can be seen in the UK, where the government started a 'proptech innovation fund'. Under the banner of 'proptech' this saw initially investment in citizen involvement solutions. More recent developments see applications in land assessment. == Investment in real estate technology == During the 2010s, numerous property technology startups were created, dealing with aspects of real estate such as design and construction, listings, and transactions. These startups have been supported by seed funding and investment from a range of sources, particularly venture capital funds. In 2015, investment into property technology grew, with more than $1.7 billion in funding being invested across over 190 deals. This represented a 50% increase year-over-year and a 821% increase in funding compared to 2011. Deal activity also increased, growing 378% with respect to 2011's total, and 12% year-over-year. This investment appeared to increase further in 2017 to £8.5 billion. In the first six months of 2019, $12.9 billion of venture capital funding was invested into real-estate technology startups, which surpassed the $12.7 billion of investments in 2017. == References ==
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A white paper is a report or guide that informs readers concisely about a complex issue and presents the issuing body's philosophy on the matter. It is meant to help readers understand an issue, solve a problem, or make a decision. Since the 1990s, this type of document has proliferated in business. Today, a business-to-business (B2B) white paper falls under grey literature, more akin to a marketing presentation meant to persuade customers and partners, and promote a certain product or viewpoint. The term originated in the 1920s to mean a type of position paper or industry report published by a department of the UK government. == In government == The term white paper originated with the British government, with the Churchill White Paper of 1922 being an early example. In the British government, a white paper is usually the less extensive version of the so-called blue book, both terms being derived from the colour of the document's cover. White papers are a "tool of participatory democracy ... not [an] unalterable policy commitment". "White papers have tried to perform the dual role of presenting firm government policies while at the same time inviting opinions upon them." In Canada, a white paper is "a policy document, approved by Cabinet, tabled in the House of Commons and made available to the general public". The "provision of policy information through the use of white and green papers can help to create an awareness of policy issues among parliamentarians and the public and to encourage an exchange of information and analysis. They can also serve as educational techniques." White papers are a way the government can present policy preferences before it introduces legislation. Publishing a white paper tests public opinion on controversial policy issues and helps the government gauge its probable impact. By contrast, green papers, which are issued much more frequently, are more open-ended. Also known as consultation documents, green papers may merely propose a strategy to implement in the details of other legislation, or they may set out proposals on which the government wishes to obtain public views and opinion. Examples of governmental white papers include, in Australia, Full Employment in Australia and, in the United Kingdom, the White Paper of 1939 and the 1966 Defence White Paper. In Israeli history, the British White Paper of 1939 – marking a sharp turn against Zionism in British policy and at the time greeted with great anger by the Jewish Yishuv community in Mandatory Palestine – is remembered as "The White Paper" (in Hebrew Ha'Sefer Ha'Lavan הספר הלבן – literally "The White Book"). == In business-to-business marketing == Since the early 1990s, the terms "white paper" or "whitepaper" have been applied to documents used as marketing or sales tools in business. These white papers are long-form content designed to promote the products or services from a specific company. As a marketing tool, these papers use selected facts and logical arguments to build a case favorable to the company sponsoring the document. B2B (business-to-business) white papers are often used to generate sales leads, establish thought leadership, make a business case, grow email lists, grow audiences, increase sales, or inform and persuade readers. The audiences for a B2B white paper can include prospective customers, channel partners, journalists, analysts, investors, or any other stakeholders. White papers are considered to be a form of content marketing or inbound marketing; in other words, sponsored content available on the web with or without registration, intended to raise the visibility of the sponsor in search engine results and build web traffic. Many B2B white papers argue that one particular technology, product, ideology, or methodology is superior to all others for solving a specific business problem. They may also present research findings, list a set of questions or tips about a certain business issue, or highlight a particular product or service from a vendor. There are, essentially, three main types of commercial white papers: Backgrounder: Describes the technical or business benefits of a certain vendor's offering; either a product, service, or methodology. This type of white paper is best used to supplement a product launch, argue a business case, or support a technical evaluation at the bottom of the sales funnel or the end of the customer journey. This is the least challenging type to produce, since much of the content is readily available in-house at the sponsor. Numbered list: Presents a set of tips, questions, or points about a certain business issue. This type is best used to get attention with new or provocative views, or cast aspersions on competitors. Also called a listicle this is the fastest type to create; a numbered list can often be devised from a single brainstorming session, and each item can be presented as an isolated point, not part of any step-by-step logical argument. Problem/solution: Recommends a new, improved solution to a nagging business problem. This type is best used to generate leads at the top of the sales funnel or the start of the customer journey, build mind share, or inform and persuade stakeholders, building trust and credibility in the subject. This is the most challenging type to produce, since it requires research gathered from third-party sources and used as proof points in building a logical argument. While a numbered list may be combined with either other type, it is not workable to combine a backgrounder with a problem/solution white paper. While a backgrounder looks inward at the details of one particular product or service, a problem/solution looks outward at an industry-wide problem. This is rather like the difference between looking through a microscope and looking through a telescope. == Variants == Several variations on the colour theme exist: The green paper is a proposal or consultative document rather than being authoritative or final. The Red Book, the UK Chancellors Budget will set out the highlights and reasoning behind the governments proposed taxation and spending policies in a White Paper called The Financial Statement and Budget Report (FSBR) while an accompanying document called the Red Book will contain the detailed financial costings of the policies, estimates of revenue and forecasts for public sector borrowing. Two others are much less well established: A blue paper sets out technical specifications of a technology or item of equipment. A yellow paper is a document containing research that has not yet been formally accepted or published in an academic journal. It is synonymous with the more widely used term preprint. == See also == Research paper Blue book (disambiguation) Case study Green paper Grey literature Persuasive writing E-publishing == References == == Further reading == Graham, Gordon (2013). White Papers For Dummies. New York: Wiley. p. 366. ISBN 978-1-118-49692-3. Stelzner, Michael (2006). Writing White Papers: How to capture readers and keep them engaged. Poway, California: WhitePaperSource Publishing. p. 214. ISBN 978-0-9777169-3-7. Bly, Robert W. (2006). The White Paper Marketing Handbook. Florence, Kentucky: South-Western Educational Publishing. p. 256. ISBN 978-0-324-30082-6. == External links == White paper – EU glossary
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Since the mid-20th century, electron-beam technology has provided the basis for a variety of novel and specialized applications in semiconductor manufacturing, microelectromechanical systems, nanoelectromechanical systems, and microscopy. == Mechanism == Free electrons in a vacuum can be manipulated by electric and magnetic fields to form a fine beam. Where the beam collides with solid-state matter, electrons are converted into heat or kinetic energy. This concentration of energy in a small volume of matter can be precisely controlled by the fields, which brings many advantages. == Applications == Electron beam techniques include electron probe microanalysis, transmission electron microscopy, auger spectroscopy, and scanning electron microscopy. The rapid increase of temperature at the location of impact can quickly melt a target material. In extreme working conditions, the rapid temperature increase can lead to evaporation, making an electron beam an excellent tool in heating applications, such as welding or electron beam evaporation. Electron beam technology is used in cable-isolation treatment, in electron lithography of sub-micrometer and nano-dimensional images, in microelectronics for electron-beam curing of color printing and for the fabrication and modification of polymers, including liquid-crystal films, among many other applications. === Furnaces === In a vacuum, the electron beam provides a source of heat that can melt or modify any material. This source of heat or phase transformation is absolutely sterile due to the vacuum and scull of solidified metal around the cold copper crucible walls. This ensures that the purest materials can be produced and refined in electron-beam vacuum furnaces. Rare and refractory metals can be produced or refined in small-volume vacuum furnaces. For mass production of steels, large furnaces with capacity measured in metric tons and electron-beam power in megawatts exist in industrialized countries. === Welding === Since the beginning of electron-beam welding on an industrial scale at the end of the 1950s, countless electron-beam welders have been designed and are being used worldwide. These welders feature working vacuum chambers ranging from a few liters up to hundreds of cubic meters, with electron guns carrying power of up to 100 kW. === Surface treatments === Modern electron-beam welders are usually designed with a computer-controlled deflection system that can traverse the beam rapidly and accurately over a selected area of the work piece. Thanks to the rapid heating, only a thin surface layer of the material is heated. Applications include hardening, annealing, tempering, texturing, and polishing (with argon gas present). If the electron beam is used to cut a shallow trough in the surface, repeatedly moving it horizontally along the trough at high speeds creates a small pile of ejected melted metal. With repetition, spike structures of up to a millimeter in height can be created. These structures can aid bonding between different materials and modify the surface roughness of the metal. === Additive manufacturing === Additive manufacturing is the process of joining materials to make objects from 3D model data, usually by melting powder material layer upon layer. Melting in a vacuum by using a computer-controlled scanning electron beam is highly precise. Electron-beam direct manufacturing (DM) is the first commercially available, large-scale, fully programmable means of achieving near net shape parts. === Metal powder production === The source billet metal is melted by an electron beam while being spun vigorously. Powder is produced as the metal cools when flying off the metal bar. === Machining === Electron-beam machining is a process in which high-velocity electrons are concentrated into a narrow beam with a very high planar power density. The beam cross-section is then focused and directed toward the work piece, creating heat and vaporizing the material. Electron-beam machining can be used to accurately cut or bore a wide variety of metals. The resulting surface finish is better and kerf width is narrower than what can be produced by other thermal cutting processes. However, due to high equipment costs, the use of this technology is limited to high-value products. === Lithography === An electron lithograph is produced by a very finely focused electron beam, which creates micro-structures in the resist that can subsequently be transferred to the substrate material, often by etching. It was originally developed for manufacturing integrated circuits and is also used for creating nanotechnology architectures. Electron lithographs uses electron beams with diameters ranging from two nanometers up to hundreds of nanometers. The electron lithograph is also used to produce computer-generated holograms (CGH). Maskless electron lithography has found wide usage in photomask making for photolithography, low-volume production of semiconductor components, and research and development activities. === Physical-vapor-deposition solar-cell production === Physical vapor deposition takes place in a vacuum and produces a thin film of solar cells by depositing thin layers of metals onto a backing structure. Electron-beam evaporation uses thermionics emission to create a stream of electrons that are accelerated by a high-voltage cathode and anode arrangement. Electrostatic and magnetic fields focus and direct the electrons to strike a target. The kinetic energy is transformed into thermal energy at or near the surface of the material. The resulting heating causes the material to melt and then evaporate. Temperatures in excess of 3500 degrees Celsius can be reached. The vapor from the source condenses onto a substrate, creating a thin film of high-purity material. Film thicknesses from a single atomic layer to many micrometers can be achieved. This technique is used in microelectronics, optics, and material research, and to produce solar cells and many other products. === Curing and sterilization === Electron-beam curing is a method of curing paints and inks without the need for traditional solvent. Electron-beam curing produces a finish similar to that of traditional solvent-evaporation processes, but achieves that finish through a polymerization process. E-beam processing is also used to cross-link polymers to make them more resistant to thermal, mechanical or chemical stresses. E-beam processing has been used for the sterilization of medical products and aseptic packaging materials for foods, as well as disinfestation, the elimination of live insects from grain, tobacco, and other unprocessed bulk crops. === Electron microscopes === An electron microscope uses a controlled beam of electrons to illuminate a specimen and produce a magnified image. Two common types are the scanning electron microscope (SEM) and the transmission electron microscope (TEM). === Medical radiation therapy === Electron beams impinging on metal produce X-rays. The X-rays may be diagnostic, e.g., dental or limb images. Often in these X-ray tubes the metal is a spinning disk so that it doesn't melt; the disk is spun in vacuum via a magnetic motor. The X-rays may also be used to kill cancerous tissue. The Therac-25 machine is an infamous example of this. == History == Electron beam technology ultimately derives from work that lead to the discovery of the electron at a time when electron beams were called cathode rays. Key advances in technology to control electron beams lead resulted in the first useful scanning electron microscope in 1952 by McMullan in Charles Oatley's lab at Cambridge University. A series of PhD students in that lab continued to improved the technique. Thomas Eugene Everhart, working mostly on semiconductor surfaces, developed the voltage contrast technique and the Everhart-Thornley detector. == References == == Bibliography == Schultz, H.: Electron beam welding, Abington Publishing Von Dobeneck, D.: Electron Beam Welding – Examples of 30 Years of Job-Shop Experience elfik.isibrno.cz/en : Electron beam welding (in Czech and/or English) Visser, A.: Werkstoffabtrag durch Elektronen-und Photonenstrahlen; Verlag <Technische Rundschau>, Blaue Reihe, Heft 104 Klein, J., Ed., Welding: Processes, Quality and Applications, Nova Science Publishers, Inc., N.Y., Chapters 1 and 2, pp. 1–166 Nemtanu, M. R., Brasoveanu, M., Ed., Practical Aspects and applications of Electron Beam Irradiation, Transworld Research Network, 37/661(2), Fort P.O., Trivandrum-695 023, Kerala, India
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Membrane technology encompasses the scientific processes used in the construction and application of membranes. Membranes are used to facilitate the transport or rejection of substances between mediums, and the mechanical separation of gas and liquid streams. In the simplest case, filtration is achieved when the pores of the membrane are smaller than the diameter of the undesired substance, such as a harmful microorganism. Membrane technology is commonly used in industries such as water treatment, chemical and metal processing, pharmaceuticals, biotechnology, the food industry, as well as the removal of environmental pollutants. After membrane construction, there is a need to characterize the prepared membrane to know more about its parameters, like pore size, function group, material properties, etc., which are difficult to determine in advance. In this process, instruments such as the Scanning Electron Microscope, the Transmission electron Microscope, the Fourier Transform Infrared Spectroscopy, X-ray Diffraction, and Liquid–Liquid Displacement Porosimetry are utilized. == Introduction == Membrane technology covers all engineering approaches for the transport of substances between two fractions with the help of semi-permeable membranes. In general, mechanical separation processes for separating gaseous or liquid streams use membrane technology. In recent years, different methods have been used to remove environmental pollutants, like adsorption, oxidation, and membrane separation. Different pollution occurs in the environment like air pollution, waste water pollution etc. As per industry requirement to prevent industrial pollution because more than 70% of environmental pollution occurs due to industries. It is their responsibility to follow government rules of the Air Pollution Control & Prevention Act 1981 to maintain and prevent the harmful chemical release into the environment. Make sure to do prevention & safety processes after that industries are able to release their waste in the environment. Biomass-based Membrane technology is one of the most promising technologies for use as a pollutants removal weapon because it has low cost, more efficiency, & lack of secondary pollutants. Typically polysulfone, polyvinylidene fluoride, and polypropylene are used in the membrane preparation process. These membrane materials are non-renewable and non-biodegradable which create harmful environmental pollution. Researchers are trying to find a solution to synthesize an eco-friendly membrane which avoids environmental pollution. Synthesis of biodegradable material with the help of naturally available material such as biomass-based membrane synthesis can be used to remove pollutants. === Membrane Overview === Membrane separation processes operate without heating and therefore use less energy than conventional thermal separation processes such as distillation, sublimation or crystallization. The separation process is purely physical and both fractions (permeate and retentate) can be obtained as useful products. Cold separation using membrane technology is widely used in the food technology, biotechnology and pharmaceutical industries. Furthermore, using membranes enables separations to take place that would be impossible using thermal separation methods. For example, it is impossible to separate the constituents of azeotropic liquids or solutes which form isomorphic crystals by distillation or recrystallization but such separations can be achieved using membrane technology. Depending on the type of membrane, the selective separation of certain individual substances or substance mixtures is possible. Important technical applications include the production of drinking water by reverse osmosis. In waste water treatment, membrane technology is becoming increasingly important. Ultra/microfiltration can be very effective in removing colloids and macromolecules from wastewater. This is needed if wastewater is discharged into sensitive waters especially those designated for contact water sports and recreation. About half of the market is in medical applications such as artificial kidneys to remove toxic substances by hemodialysis and as artificial lung for bubble-free supply of oxygen in the blood. The importance of membrane technology is growing in the field of environmental protection (Nano-Mem-Pro IPPC Database). Even in modern energy recovery techniques, membranes are increasingly used, for example in fuel cells and in osmotic power plants. == Mass transfer == Two basic models can be distinguished for mass transfer through the membrane: the solution-diffusion model and the hydrodynamic model. In real membranes, these two transport mechanisms certainly occur side by side, especially during ultra-filtration. === Solution-diffusion model === In the solution-diffusion model, transport occurs only by diffusion. The component that needs to be transported must first be dissolved in the membrane. The general approach of the solution-diffusion model is to assume that the chemical potential of the feed and permeate fluids are in equilibrium with the adjacent membrane surfaces such that appropriate expressions for the chemical potential in the fluid and membrane phases can be equated at the solution-membrane interface. This principle is more important for dense membranes without natural pores such as those used for reverse osmosis and in fuel cells. During the filtration process a boundary layer forms on the membrane. This concentration gradient is created by molecules which cannot pass through the membrane. The effect is referred to as concentration polarization and, occurring during the filtration, leads to a reduced trans-membrane flow (flux). Concentration polarization is, in principle, reversible by cleaning the membrane which results in the initial flux being almost totally restored. Using a tangential flow to the membrane (cross-flow filtration) can also minimize concentration polarization. === Hydrodynamic model === Transport through pores – in the simplest case – is done convectively. This requires the size of the pores to be smaller than the diameter of the two separate components. Membranes that function according to this principle are used mainly in micro- and ultrafiltration. They are used to separate macromolecules from solutions, colloids from a dispersion or remove bacteria. During this process, the retained particles or molecules form a pulpy mass (filter cake) on the membrane, and this blockage of the membrane hampers the filtration. This blockage can be reduced by the use of the cross-flow method (cross-flow filtration). Here, the liquid to be filtered flows along the front of the membrane and is separated by the pressure difference between the front and back of the membrane into retentate (the flowing concentrate) on the front and permeate (filtrate) on the back. The tangential flow on the front creates a shear stress that cracks the filter cake and reduces the fouling. == Membrane operations == According to the driving force of the operation, it is possible to distinguish: Pressure-driven operations microfiltration ultrafiltration nanofiltration reverse osmosis gas separation Concentration driven operations dialysis pervaporation forward osmosis artificial lung Operations in an electric potential gradient electrodialysis membrane electrolysis e.g. chloralkaline process electrode ionization electro filtration fuel cell Operations in a temperature gradient membrane distillation == Membrane shapes and flow geometries == There are two main flow configurations of membrane processes: cross-flow (or tangential flow) and dead-end filtrations. In cross-flow filtration the feed flow is tangential to the surface of the membrane, retentate is removed from the same side further downstream, whereas the permeate flow is tracked on the other side. In dead-end filtration, the direction of the fluid flow is normal to the membrane surface. Both flow geometries offer some advantages and disadvantages. Generally, dead-end filtration is used for feasibility studies on a laboratory scale. The dead-end membranes are relatively easy to fabricate which reduces the cost of the separation process. The dead-end membrane separation process is easy to implement and the process is usually cheaper than cross-flow membrane filtration. The dead-end filtration process is usually a batch-type process, where the filtering solution is loaded (or slowly fed) into the membrane device, which then allows passage of some particles subject to the driving force. The main disadvantage of dead-end filtration is the extensive membrane fouling and concentration polarization. The fouling is usually induced faster at higher driving forces. Membrane fouling and particle retention in a feed solution also builds up a concentration gradients and particle backflow (concentration polarization). The tangential flow devices are more cost and labor-intensive, but they are less susceptible to fouling due to the sweeping effects and high shear rates of the passing flow. The most commonly used synthetic membrane devices (modules) are flat sheets/plates, spiral wounds, and hollow fibers. Flat membranes used in filtration and separation processes can be enhanced with surface patterning, where microscopic structures are introduced to improve performance. These patterns increase surface area, optimize water flow, and reduce fouling, leading to higher permeability and longer membrane lifespan. Research has shown that such modifications can significantly enhance efficiency in water purification, energy applications, and industrial separations. Flat plates are usually constructed as circular thin flat membrane surfaces to be used in dead-end geometry modules. Spiral wounds are constructed from similar flat membranes but in the form of a "pocket" containing two membrane sheets separated by a highly porous support plate. Several such pockets are then wound around a tube to create a tangential flow geometry and to reduce membrane fouling. Hollow fiber modules consist of an assembly of self-supporting fibers with dense skin separation layers, and a more open matrix helping to withstand pressure gradients and maintain structural integrity. The hollow fiber modules can contain up to 10,000 fibers ranging from 200 to 2500 μm in diameter; The main advantage of hollow fiber modules is the very large surface area within an enclosed volume, increasing the efficiency of the separation process. The Disc tube module uses a cross-flow geometry and consists of a pressure tube and hydraulic discs, which are held by a central tension rod, and membrane cushions that lie between two discs. == Membrane performance and governing equations == The selection of synthetic membranes for a targeted separation process is usually based on few requirements. Membranes have to provide enough mass transfer area to process large amounts of feed stream. The selected membrane has to have high selectivity (rejection) properties for certain particles; it has to resist fouling and to have high mechanical stability. It also needs to be reproducible and to have low manufacturing costs. The main modeling equation for the dead-end filtration at constant pressure drop is represented by Darcy's law: d V p d t = Q = Δ p μ A ( 1 R m + R ) {\displaystyle {\frac {dV_{p}}{dt}}=Q={\frac {\Delta p}{\mu }}\ A\left({\frac {1}{R_{m}+R}}\right)} where Vp and Q are the volume of the permeate and its volumetric flow rate respectively (proportional to same characteristics of the feed flow), μ is dynamic viscosity of permeating fluid, A is membrane area, Rm and R are the respective resistances of membrane and growing deposit of the foulants. Rm can be interpreted as a membrane resistance to the solvent (water) permeation. This resistance is a membrane intrinsic property and is expected to be fairly constant and independent of the driving force, Δp. R is related to the type of membrane foulant, its concentration in the filtering solution, and the nature of foulant-membrane interactions. Darcy's law allows for calculation of the membrane area for a targeted separation at given conditions. The solute sieving coefficient is defined by the equation: S = C p C f {\displaystyle S={\frac {C_{p}}{C_{f}}}} where Cf and Cp are the solute concentrations in feed and permeate respectively. Hydraulic permeability is defined as the inverse of resistance and is represented by the equation: L p = J Δ p {\displaystyle L_{p}={\frac {J}{\Delta p}}} where J is the permeate flux which is the volumetric flow rate per unit of membrane area. The solute sieving coefficient and hydraulic permeability allow the quick assessment of the synthetic membrane performance. == Membrane separation processes == Membrane separation processes have a very important role in the separation industry. Nevertheless, they were not considered technically important until the mid-1970s. Membrane separation processes differ based on separation mechanisms and size of the separated particles. The widely used membrane processes include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrolysis, dialysis, electrodialysis, gas separation, vapor permeation, pervaporation, membrane distillation, and membrane contactors. All processes except for pervaporation involve no phase change. All processes except electrodialysis are pressure driven. Microfiltration and ultrafiltration is widely used in food and beverage processing (beer microfiltration, apple juice ultrafiltration), biotechnological applications and pharmaceutical industry (antibiotic production, protein purification), water purification and wastewater treatment, the microelectronics industry, and others. Nanofiltration and reverse osmosis membranes are mainly used for water purification purposes. Dense membranes are utilized for gas separations (removal of CO2 from natural gas, separating N2 from air, organic vapor removal from air or a nitrogen stream) and sometimes in membrane distillation. The later process helps in the separation of azeotropic compositions reducing the costs of distillation processes. == Pore size and selectivity == The pore sizes of technical membranes are specified differently depending on the manufacturer. One common distinction is by nominal pore size. It describes the maximum pore size distribution and gives only vague information about the retention capacity of a membrane. The exclusion limit or "cut-off" of the membrane is usually specified in the form of NMWC (nominal molecular weight cut-off, or MWCO, molecular weight cut off, with units in Dalton). It is defined as the minimum molecular weight of a globular molecule that is retained to 90% by the membrane. The cut-off, depending on the method, can by converted to so-called D90, which is then expressed in a metric unit. In practice the MWCO of the membrane should be at least 20% lower than the molecular weight of the molecule that is to be separated. Using track etched mica membranes Beck and Schultz demonstrated that hindered diffusion of molecules in pores can be described by the Rankin equation. Filter membranes are divided into four classes according to pore size: The form and shape of the membrane pores are highly dependent on the manufacturing process and are often difficult to specify. Therefore, for characterization, test filtrations are carried out and the pore diameter refers to the diameter of the smallest particles which could not pass through the membrane. The rejection can be determined in various ways and provides an indirect measurement of the pore size. One possibility is the filtration of macromolecules (often dextran, polyethylene glycol or albumin), another is measurement of the cut-off by gel permeation chromatography. These methods are used mainly to measure membranes for ultrafiltration applications. Another testing method is the filtration of particles with defined size and their measurement with a particle sizer or by laser induced breakdown spectroscopy (LIBS). A vivid characterization is to measure the rejection of dextran blue or other colored molecules. The retention of bacteriophage and bacteria, the so-called "bacteria challenge test", can also provide information about the pore size. To determine the pore diameter, physical methods such as porosimeter (mercury, liquid-liquid porosimeter and Bubble Point Test) are also used, but a certain form of the pores (such as cylindrical or concatenated spherical holes) is assumed. Such methods are used for membranes whose pore geometry does not match the ideal, and we get "nominal" pore diameter, which characterizes the membrane, but does not necessarily reflect its actual filtration behavior and selectivity. The selectivity is highly dependent on the separation process, the composition of the membrane and its electrochemical properties in addition to the pore size. With high selectivity, isotopes can be enriched (uranium enrichment) in nuclear engineering or industrial gases like nitrogen can be recovered (gas separation). Ideally, even racemics can be enriched with a suitable membrane. When choosing membranes selectivity has priority over a high permeability, as low flows can easily be offset by increasing the filter surface with a modular structure. In gas phase filtration different deposition mechanisms are operative, so that particles having sizes below the pore size of the membrane can be retained as well. == Membrane Classification == Bio-Membrane is classified in two categories, synthetic membrane and natural membrane. synthetic membranes further classified in organic and inorganic membranes. Organic membrane sub classified polymeric membranes and inorganic membrane sub classified ceramic polymers. == Synthesis of Biomass Membrane == === The composite biomass membrane === Green membrane or Bio-membrane synthesis is the solution to protected environments which have largely comprehensive performance. Biomass is used in the form of activated carbon nanoparticles, like using cellulose based biomass coconut shell, hazelnut shell, walnut shell, agricultural wastes of corn stalks etc. which improve surface hydrophilicity, larger pore size, more and lower surface roughness therefore, the separation and anti-fouling performance of membranes are also improved simultaneously. === Fabrication of pure biomass based membrane === A biomass-based membrane is a membrane made from organic materials such as plant fibers. These membranes are often used in water filtration and wastewater treatment applications. The fabrication of a pure biomass-based membrane is a complex process that involves a number of steps. The first step is to create a slurry of the organic materials. This slurry is then cast onto a substrate, such as a glass or metal plate. The cast is then dried, and the resulting membrane is then subjected to a number of treatments, such as chemical or heat treatments, to improve its properties. One of the challenges in the fabrication of biomass-based membranes is to create a membrane with the desired properties. == Equipment and instruments used in the process == List of instruments used in membrane synthesis procedures: Centrifuge Casting Machine Plane casting glass Magnetic Stirrer Glass ware: Beakers, measuring cylinders, flask etc. Oven Mortar and pestle == Membrane Characterization == After casting and synthesis of membrane there is need to characterize the prepared membrane to know more details about membrane parameters, like pore size, functional groups, wettability, surface charge, etc. It is important to know membrane properties so we are able to remove and treat a particulate pollutant, which causes pollution in the environment. For characterization following different instruments are used: Scanning Electron Microscope (SEM) Transmission electron Microscope (TEM) Fourier Transform Infrared Spectroscopy (FTIR) Atomic force microscopy Contact angle meter Zeta potential (streaming potential) X-ray Diffraction (XRD) Liquid–Liquid Displacement Porosimetry (LLDP) == Biomass Membrane Applications == === Water treatment === Water treatment is any process that improves the quality of water to make it more acceptable for a specific end-use. Membranes can be used to remove particulates from water by either size exclusion or charge separation. In size exclusion, the pores in the membrane are sized such that only particles smaller than the pores can pass through. The pores in the membrane are sized such that only water molecules can pass through, leaving dissolved contaminants behind. === Gas separation === Utilization of membranes in gas separation, like carbon dioxide (CO2), Nitrogen oxides (NOx), Sulphur oxides (SOx), harmful gasses can be removed to protect the environment. Biomass Membrane gas separation more effective than commercial membrane. === Hemodialysis === Membrane application in hemodialysis is a process of using a semipermeable membrane to remove waste products and excess fluids from the blood. == See also == Particle deposition Synthetic membrane == Notes == == References == Osada, Y., Nakagawa, T., Membrane Science and Technology, New York: Marcel Dekker, Inc,1992. Zeman, Leos J., Zydney, Andrew L., Microfiltration and Ultrafitration, Principles and Applications., New York: Marcel Dekker, Inc,1996. Mulder M., Basic Principles of Membrane Technology, Kluwer Academic Publishers, Netherlands, 1996. Jornitz, Maik W., Sterile Filtration, Springer, Germany, 2006 Van Reis R., Zydney A. Bioprocess membrane technology. J Mem Sci. 297(2007): 16-50. Templin T., Johnston D., Singh V., Tumbleson M.E., Belyea R.L. Rausch K.D. Membrane separation of solids from corn processing streams. Biores Tech. 97(2006): 1536-1545. Ripperger S., Schulz G. Microporous membranes in biotechnical applications. Bioprocess Eng. 1(1986): 43-49. Thomas Melin, Robert Rautenbach, Membranverfahren, Springer, Germany, 2007, ISBN 3-540-00071-2. Munir Cheryan, Handbuch Ultrafiltration, Behr, 1990, ISBN 3-925673-87-3. Eberhard Staude, Membranen und Membranprozesse, VCH, 1992, ISBN 3-527-28041-3.
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Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures. The term covers a range of methods used to make personnel, aircraft, ships, submarines, missiles, satellites, and ground vehicles less visible (ideally invisible) to radar, infrared, sonar and other detection methods. It corresponds to military camouflage for these parts of the electromagnetic spectrum (i.e., multi-spectral camouflage). Development of modern stealth technologies in the United States began in 1958, where earlier attempts to prevent radar tracking of its U-2 spy planes during the Cold War by the Soviet Union had been unsuccessful. Designers turned to developing a specific shape for planes that tended to reduce detection by redirecting electromagnetic radiation waves from radars. Radiation-absorbent material was also tested and made to reduce or block radar signals that reflect off the surfaces of aircraft. Such changes to shape and surface composition comprise stealth technology as currently used on the Northrop Grumman B-2 Spirit "Stealth Bomber". The concept of stealth is to operate or hide while giving enemy forces no indication as to the presence of friendly forces. This concept was first explored through camouflage to make an object's appearance blend into the visual background. As the potency of detection and interception technologies (radar, infrared search and tracking, surface-to-air missiles, etc.) have increased, so too has the extent to which the design and operation of military personnel and vehicles have been affected in response. Some military uniforms are treated with chemicals to reduce their infrared signature. A modern stealth vehicle is designed from the outset to have a chosen spectral signature. The degree of stealth embodied in a given design is chosen according to the projected threats of detection. == History == Camouflage to aid or avoid predation predates humanity, and hunters have been using vegetation to conceal themselves, perhaps as long as people have been hunting. The earliest application of camouflage in warfare is impossible to ascertain. Methods for visual concealment in war were documented by Sun Tzu in his book The Art of War in the 5th century BC, and by Frontinus in his work Strategemata in the 1st century AD. In England, irregular units of gamekeepers in the 17th century were the first to adopt drab colours (common in 16th century Irish units) as a form of camouflage, following examples from the continent. During World War I, the Germans experimented with the use of Cellon (Cellulose acetate), a transparent covering material, in an attempt to reduce the visibility of military aircraft. Single examples of the Fokker E.III Eindecker fighter monoplane, the Albatros C.I two-seat observation biplane, and the Linke-Hofmann R.I prototype heavy bomber were covered with Cellon. However, sunlight glinting from the material made the aircraft even more visible. Cellon was also found to degrade quickly from both sunlight and in-flight temperature changes, so the effort to make transparent aircraft ceased. In 1916, the British modified a small SS class airship for the purpose of night-time reconnaissance over German lines on the Western Front. Fitted with a silenced engine and a black gas bag, the craft was both invisible and inaudible from the ground but several night-time flights over German-held territory produced little useful intelligence and the idea was dropped. Diffused lighting camouflage, a shipborne form of counter-illumination camouflage, was trialled by the Royal Canadian Navy from 1941 to 1943. The concept was followed up for aircraft by the Americans and the British: in 1945, a Grumman Avenger aircraft with Yehudi lights reached 3,000 yards (2,700 m) from a ship before being sighted. This ability was rendered obsolete by radar. Chaff was invented in Britain and Germany early in World War II as a means to hide aircraft from radar. In effect, chaff acted upon radio waves much as a smoke screen acted upon visible light. The German U-boat U-480 may have been the first stealth submarine. It featured an anechoic tile rubber coating, one layer of which contained circular air pockets to defeat ASDIC sonar. Radar-absorbent paints and materials of rubber and semiconductor composites (codenames: Sumpf, Schornsteinfeger) were used by the Kriegsmarine on submarines in World War II. Tests showed they were effective in reducing radar signatures at both short (centimetres) and long (1.5 metre) wavelengths. In 1956, the U.S. Central Intelligence Agency (CIA) began attempts to reduce the radar cross-section (RCS) of the U-2 spy plane. Three systems were developed, Trapeze, a series of wires and ferrite beads around the planform of the aircraft, a covering material with PCB circuitry embedded in it, and radar-absorbent paint. These were deployed in the field on the so-called dirty birds but results were disappointing, the weight and drag increases were not worth any reduction in detection rates. More successful was applying camouflage paint to the originally bare metal aircraft; a deep blue was found to be most effective. The weight of this cost 250 ft (76 m) in maximum altitude, but made the aircraft harder for interceptors to see. In 1958, the CIA requested funding for a reconnaissance aircraft to replace the existing U-2 spy planes, and Lockheed secured contractual rights to produce it. "Kelly" Johnson and his team at Lockheed's Skunk Works were assigned to produce the A-12 (or OXCART), which operated at high altitude of 70,000 to 80,000 ft (21,000 to 24,000 m) and speed of Mach 3.2 (2,400 mph; 3,800 km/h) to avoid radar detection. Various plane shapes designed to reduce radar detection were developed in earlier prototypes, named A-1 to A-11. The A-12 included a number of stealthy features including special fuel to reduce the signature of the exhaust plume, canted vertical stabilizers, the use of composite materials in key locations, and the overall finish in radar-absorbent paint. In 1960, the United States Air Force (USAF) reduced the radar cross-section of a Ryan Q-2C Firebee drone. This was achieved through specially designed screens over the air intake, and radiation-absorbent material on the fuselage, and radar-absorbent paint. The United States Army issued a specification in 1968 which called for an observation aircraft that would be acoustically undetectable from the ground when flying at an altitude of 1,500 ft (460 m) at night. This resulted in the Lockheed YO-3A Quiet Star, which operated in South Vietnam from late June 1970 to September 1971. During the 1970s, the U.S. Department of Defense launched project Lockheed Have Blue, with the aim of developing a stealth fighter. There was fierce bidding between Lockheed and Northrop to secure the multibillion-dollar contract. Lockheed incorporated into its bid a text written by the Soviet-Russian physicist Pyotr Ufimtsev from 1962, titled Method of Edge Waves in the Physical Theory of Diffraction, Soviet Radio, Moscow, 1962. In 1971, this book was translated into English with the same title by the USAF, Foreign Technology Division. The theory played a critical role in the design of American Lockheed F-117 Nighthawk and Northrop B-2 Spirit stealth aircraft. Equations outlined in the paper quantified how a plane's shape would affect its detectability by radar, the RCS. At the time, the Soviet Union did not have supercomputer capacity to solve these equations for actual designs. This was applied by Lockheed in computer simulation to design a novel shape they called the "Hopeless Diamond", a wordplay on the Hope Diamond, securing contractual rights to produce the F-117 Nighthawk starting in 1975. In 1977, Lockheed produced two 60% scale models under the Have Blue contract. The Have Blue program was a stealth technology demonstrator that lasted from 1976 to 1979. The Northrop Grumman Tacit Blue also played a part in the development of composite material and curvilinear surfaces, low observables, fly-by-wire, and other stealth technology innovations. The success of Have Blue led the USAF to create the Senior Trend program which developed the F-117. In the early 21st century, the proliferation of stealth technology began outside of the United States. Both Russia and China tested their stealth aircraft in 2010. Russia manufactured ten flyable prototypes of the Sukhoi Su-57, while China produced two stealth aircraft, Chengdu J-20 and Shenyang FC-31. In 2017, China became the second country in the world to field an operational stealth aircraft, challenging the United States and its Asian allies. == Principles == Stealth technology (or LO for low observability) is not one technology. It is a set of technologies, used in combinations, that can greatly reduce the distances at which a person or vehicle can be detected; more so radar cross-section reductions, but also acoustic, thermal, and other aspects. == Radar cross-section (RCS) reductions == Almost since the invention of radar, various methods have been tried to minimize detection. Rapid development of radar during World War II led to equally rapid development of numerous counter radar measures during the period; a notable example of this was the use of chaff. Modern methods include radar jamming and deception. The term stealth in reference to reduced radar signature aircraft became popular during the late 1980s when the Lockheed Martin F-117 stealth fighter became widely known. The first large scale (and public) use of the F-117 was during the Gulf War in 1991. However, F-117A stealth fighters were used for the first time in combat during Operation Just Cause, the United States invasion of Panama in 1989. Stealth aircraft are often designed to have radar cross sections that are orders of magnitude smaller than conventional aircraft. The radar range equation meant that all else being equal, detection range is proportional to the fourth root of RCS; thus, reducing detection range by a factor of 10 requires a reduction of RCS by a factor of 10,000. === Vehicle shape === ==== Aircraft ==== The possibility of designing aircraft in such a manner as to reduce their radar cross-section was recognized in the late 1930s, when the first radar tracking systems were employed, and it has been known since at least the 1960s that aircraft shape makes a significant difference in detectability. The Avro Vulcan, a British bomber of the 1960s, had a remarkably small appearance on radar despite its large size, and occasionally disappeared from radar screens entirely. It is now known that it had a fortuitously stealthy shape apart from the vertical element of the tail. Despite being designed before a low RCS and other stealth factors were ever a consideration, a Royal Aircraft Establishment technical note of 1957 stated that of all the aircraft so far studied, the Vulcan appeared by far the simplest radar echoing object, due to its shape: only one or two components contributing significantly to the echo at any aspect (one of them being the vertical stabilizer, which is especially relevant for side aspect RCS), compared with three or more on most other types. While writing about radar systems, authors Simon Kingsley and Shaun Quegan singled out the Vulcan's shape as acting to reduce the RCS. In contrast, the Tupolev Tu-95 Russian long-range bomber (NATO reporting name 'Bear') was conspicuous on radar. It is now known that propellers and jet turbine blades produce a bright radar image; the Bear has four pairs of large 18-foot (5.6 m) diameter contra-rotating propellers. Another important factor is internal construction. Some stealth aircraft have skin that is radar transparent or absorbing, behind which are structures termed reentrant triangles. Radar waves penetrating the skin get trapped in these structures, reflecting off the internal faces and losing energy. This method was first used on the Blackbird series: A-12, YF-12A, Lockheed SR-71 Blackbird. The most efficient way to reflect radar waves back to the emitting radar is with orthogonal metal plates, forming a corner reflector consisting of either a dihedral (two plates) or a trihedral (three orthogonal plates). This configuration occurs in the tail of a conventional aircraft, where the vertical and horizontal components of the tail are set at right angles. Stealth aircraft such as the F-117 use a different arrangement, tilting the tail surfaces to reduce corner reflections formed between them. A more radical method is to omit the tail, as in the B-2 Spirit. The B-2's clean, low-drag flying wing configuration gives it exceptional range and reduces its radar profile. The flying wing design most closely resembles a so-called infinite flat plate (as vertical control surfaces dramatically increase RCS), the perfect stealth shape, as it would have no angles to reflect back radar waves. In addition to altering the tail, stealth design must bury the engines within the wing or fuselage, or in some cases where stealth is applied to an extant aircraft, install baffles in the air intakes, so that the compressor blades are not visible to radar. A stealthy shape must be devoid of complex bumps or protrusions of any kind, meaning that weapons, fuel tanks, and other stores must not be carried externally. Any stealthy vehicle becomes un-stealthy when a door or hatch opens. Parallel alignment of edges or even surfaces is also often used in stealth designs. The technique involves using a small number of edge orientations in the shape of the structure. For example, on the F-22A Raptor, the leading edges of the wing and the tail planes are set at the same angle. Other smaller structures, such as the air intake bypass doors and the air refueling aperture, also use the same angles. The effect of this is to return a narrow radar signal in a very specific direction away from the radar emitter rather than returning a diffuse signal detectable at many angles. The effect is sometimes called "glitter" after the very brief signal seen when the reflected beam passes across a detector. It can be difficult for the radar operator to distinguish between a glitter event and a digital glitch in the processing system. Stealth airframes sometimes display distinctive serrations on some exposed edges, such as the engine ports. The YF-23 has such serrations on the exhaust ports. This is another example in the parallel alignment of features, this time on the external airframe. The shaping requirements detracted greatly from the F-117's aerodynamic properties. It is inherently unstable, and cannot be flown without a fly-by-wire control system. Similarly, coating the cockpit canopy with a thin film transparent conductor (vapor-deposited gold or indium tin oxide) helps to reduce the aircraft's radar profile, because radar waves would normally enter the cockpit, reflect off objects (the inside of a cockpit has a complex shape, with a pilot helmet alone forming a sizeable return), and possibly return to the radar, but the conductive coating creates a controlled shape that deflects the incoming radar waves away from the radar. The coating is thin enough that it has no adverse effect on pilot vision. ==== Ships ==== Ships have also adopted similar methods. Though the earlier American Arleigh Burke-class destroyers incorporated some signature-reduction features. the Norwegian Skjold-class corvettes was the first coastal defence and the French La Fayette-class frigates the first ocean-going stealth ships to enter service. Other examples are the Dutch De Zeven Provinciën-class frigates, the Taiwanese Tuo Chiang-class corvettes, German Sachsen-class frigates, the Swedish Visby-class corvette, the American San Antonio-class amphibious transport docks, and most modern warship designs. === Materials === ==== Non-metallic airframe ==== Dielectric composite materials are more transparent to radar, whereas electrically conductive materials such as metals and carbon fibers reflect electromagnetic energy incident on the material's surface. Composites may also contain ferrites to optimize the dielectric and magnetic properties of a material for its application. ==== Radar-absorbent material ==== Radiation-absorbent material (RAM), often as paints, are used especially on the edges of metal surfaces. While the material and thickness of RAM coatings can vary, the way they work is the same: absorb radiated energy from a ground- or air-based radar station into the coating and convert it to heat rather than reflect it back. Current technologies include dielectric composites and metal fibers containing ferrite isotopes. Ceramic composite coating is a new type of material systems which can sustain at higher temperatures with better sand erosion resistance and thermal resistance. Paint comprises depositing pyramid-like colonies on the reflecting superficies with the gaps filled with ferrite-based RAM. The pyramidal structure deflects the incident radar energy in the maze of RAM. One commonly used material is called iron ball paint. It contains microscopic iron spheres that resonate in tune with incoming radio waves and dissipate most of their energy as heat, leaving little to reflect back to detectors. FSS are planar periodic structures that behave like filters to electromagnetic energy. The considered frequency-selective surfaces are composed of conducting patch elements pasted on the ferrite layer. FSS are used for filtration and microwave absorption. === Radar stealth countermeasures and limits === ==== Low-frequency radar ==== Shaping offers far fewer stealth advantages against low-frequency radar. If the radar wavelength is roughly twice the size of the target, a half-wave resonance effect can still generate a significant return. However, low-frequency radar is limited by lack of available frequencies (many are heavily used by other systems), by lack of accuracy of the diffraction-limited systems given their long wavelengths, and by the radar's size, making it difficult to transport. A long-wave radar may detect a target and roughly locate it, but not provide enough information to identify it, target it with weapons, or even to guide a fighter to it. ==== Multiple emitters ==== Stealth aircraft attempt to minimize all radar reflections, but are specifically designed to avoid reflecting radar waves back in the direction they came from (since in most cases a radar emitter and receiver are in the same location). They are less able to minimize radar reflections in other directions. Thus, detection can be better achieved if emitters are in different locations from receivers. One emitter separate from one receiver is termed bistatic radar; one or more emitters separate from more than one receiver is termed multistatic radar. Proposals exist to use reflections from emitters such as civilian radio transmitters, including cellular telephone radio towers. ==== Moore's law ==== By Moore's law the processing power behind radar systems is rising over time. This will eventually erode the ability of physical stealth to hide vehicles. ==== Ship wakes and spray ==== Synthetic aperture sidescan radars can be used to detect the location and heading of ships from their wake patterns. These are detectable from orbit. When a ship moves through a seaway it throws up a cloud of spray which can be detected by radar. == Acoustics == Acoustic stealth plays a primary role for submarines and ground vehicles. Submarines use extensive rubber mountings to isolate, damp, and avoid mechanical noises that can reveal locations to underwater passive sonar arrays. Early stealth observation aircraft used slow-turning propellers to avoid being heard by enemy troops below. Stealth aircraft that stay subsonic can avoid being tracked by sonic boom. The presence of supersonic and jet-powered stealth aircraft such as the SR-71 Blackbird indicates that acoustic signature is not always a major driver in aircraft design, as the Blackbird relied more on its very high speed and altitude. One method to reduce helicopter rotor noise is modulated blade spacing. Standard rotor blades are evenly spaced, and produce greater noise at a given frequency and its harmonics. Using varied spacing between the blades spreads the noise or acoustic signature of the rotor over a greater range of frequencies. == Visibility == The simplest technology is visual camouflage; the use of paint or other materials to color and break up the lines of a vehicle or person. Most stealth aircraft use matte paint and dark colors, and operate only at night. Lately, interest in daylight Stealth (especially by the USAF) has emphasized the use of gray paint in disruptive schemes, and it is assumed that Yehudi lights could be used in the future to hide the airframe (against the background of the sky, including at night, aircraft of any colour appear dark) or as a sort of active camouflage. The original B-2 design had wing tanks for a contrail-inhibiting chemical, alleged by some to be chlorofluorosulfonic acid, but this was replaced in the final design with a contrail sensor that alerts the pilot when he should change altitude and mission planning also considers altitudes where the probability of their formation is minimized. In space, mirrored surfaces can be employed to reflect views of empty space toward known or suspected observers; this approach is compatible with several radar stealth schemes. Careful control of the orientation of the satellite relative to the observers is essential, and mistakes can lead to detectability enhancement rather than the desired reduction. == Infrared == An exhaust plume contributes a significant infrared signature. One means to reduce IR signature is to have a non-circular tail pipe (a slit shape) to minimize the exhaust cross sectional area and maximize the mixing of hot exhaust with cool ambient air (see Lockheed F-117 Nighthawk, rectangular nozzles on the Lockheed Martin F-22 Raptor, and serrated nozzle flaps on the Lockheed Martin F-35 Lightning). Often, cool air is deliberately injected into the exhaust flow to boost this process (see Ryan AQM-91 Firefly and Northrop B-2 Spirit). The Stefan–Boltzmann law shows how this results in less energy (Thermal radiation in infrared spectrum) being released and thus reduces the heat signature. In some aircraft, the jet exhaust is vented above the wing surface to shield it from observers below, as in the Lockheed F-117 Nighthawk, and the unstealthy Fairchild Republic A-10 Thunderbolt II. To achieve infrared stealth, the exhaust gas is cooled to the temperatures where the brightest wavelengths it radiates are absorbed by atmospheric carbon dioxide and water vapor, greatly reducing the infrared visibility of the exhaust plume. Another way to reduce the exhaust temperature is to circulate coolant fluids such as fuel inside the exhaust pipe, where the fuel tanks serve as heat sinks cooled by the flow of air along the wings. Ground combat includes the use of both active and passive infrared sensors. Thus, the United States Marine Corps (USMC) ground combat uniform requirements document specifies infrared reflective quality standards. == Reducing radio frequency (RF) emissions == In addition to reducing infrared and acoustic emissions, a stealth vehicle must avoid radiating any other detectable energy, such as from onboard radars, communications systems, or RF leakage from electronics enclosures. The F-117 uses passive infrared and low light level television sensor systems to aim its weapons and the F-22 Raptor has an advanced LPI radar which can illuminate enemy aircraft without triggering a radar warning receiver response. == Measuring == The size of a target's image on radar is measured by the RCS, often represented by the symbol σ and expressed in square meters. This does not equal geometric area. A perfectly conducting sphere of projected cross sectional area 1 m2 (i.e. a diameter of 1.13 m) will have an RCS of 1 m2. Note that for radar wavelengths much less than the diameter of the sphere, RCS is independent of frequency. Conversely, a square flat plate of area 1 m2 will have an RCS of σ=4π A2 / λ2 (where A=area, λ=wavelength), or 13,982 m2 at 10 GHz if the radar is perpendicular to the flat surface. At off-normal incident angles, energy is reflected away from the receiver, reducing the RCS. Modern stealth aircraft are said to have an RCS comparable with small birds or large insects, though this varies widely depending on aircraft and radar. If the RCS was directly related to the target's cross-sectional area, the only way to reduce it would be to make the physical profile smaller. Rather, by reflecting much of the radiation away or by absorbing it, the target achieves a smaller radar cross section. == Tactics == Stealthy strike aircraft such as the Lockheed F-117 Nighthawk, are usually used against heavily defended enemy sites such as command and control centers or surface-to-air missile (SAM) batteries. Enemy radar will cover the airspace around these sites with overlapping coverage, making undetected entry by conventional aircraft nearly impossible. Stealthy aircraft can also be detected, but only at short ranges around the radars; for a stealthy aircraft there are substantial gaps in the radar coverage. Thus a stealthy aircraft flying an appropriate route can remain undetected by radar. Even if a stealth aircraft is detected, fire-control radars operating in C, X and Ku bands cannot paint (for missile guidance) low observable (LO) jets except at very close ranges. Many ground-based radars exploit Doppler filter to improve sensitivity to objects having a radial velocity component relative to the radar. Mission planners use their knowledge of enemy radar locations and the RCS pattern of the aircraft to design a flight path that minimizes radial speed while presenting the lowest-RCS aspects of the aircraft to the threat radar. To be able to fly these "safe" routes, it is necessary to understand an enemy's radar coverage (see electronic intelligence). Airborne or mobile radar systems such as airborne early warning and control (AEW&C, AWACS) can complicate tactical strategy for stealth operation. == Research == After the invention of electromagnetic metasurfaces, the conventional means to reduce RCS have been improved significantly. As mentioned earlier, the main objective in purpose shaping is to redirect scattered waves away from the backscattered direction, which is usually the source. However, this usually compromises aerodynamic performance. One feasible solution, which has extensively been explored in recent time, is to use metasurfaces which can redirect scattered waves without altering the geometry of a target. Such metasurfaces can primarily be classified in two categories: (i) checkerboard metasurfaces, (ii) gradient index metasurfaces. Similarly, negative index metamaterials are artificial structures for which refractive index has a negative value for some frequency range, such as in microwave, infrared, or possibly optical. These offer another way to reduce detectability, and may provide electromagnetic near-invisibility in designed wavelengths. Plasma stealth is a phenomenon proposed to use ionized gas, termed a plasma, to reduce RCS of vehicles. Interactions between electromagnetic radiation and ionized gas have been studied extensively for many purposes, including concealing vehicles from radar. Various methods might form a layer or cloud of plasma around a vehicle to deflect or absorb radar, from simpler electrostatic to radio frequency (RF) more complex laser discharges, but these may be difficult in practice. Several technology research and development efforts exist to integrate the functions of aircraft flight control systems such as ailerons, elevators, elevons, flaps, and flaperons into wings to perform the aerodynamic purpose with the advantages of lower RCS for stealth, via simpler geometries and lower complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and lower mass, cost (up to 50% less), drag (up to 15% less during use), and inertia (for faster, stronger control response to change vehicle orientation to reduce detection). Two promising approaches are flexible wings, and fluidics. In flexible wings, much or all of a wing surface can change shape in flight to deflect air flow. Adaptive compliant wings are a military and commercial effort. The X-53 Active Aeroelastic Wing was a US Air Force, Boeing, and NASA effort. In fluidics, fluid injection into airflows is being researched for use in aircraft to control direction, in two ways: circulation control and thrust vectoring. In both, larger more complex mechanical parts are replaced by smaller, simpler, lower mass fluidic systems, in which larger forces in fluids are diverted by smaller jets or flows of fluid intermittently, to change the direction of vehicles. Mechanical control surfaces that must move cause an important part of aircraft radar cross-section. Omitting mechanical control surfaces can reduce radar returns. As of 2023, at least two countries are known to be researching fluidic control. In Britain, BAE Systems has tested two fluidically controlled unmanned aircraft, one starting in 2010 named Demon, and another starting in 2017 named MAGMA, with the University of Manchester. In the United States, the Defense Advanced Research Projects Agency (DARPA) program named Control of Revolutionary Aircraft with Novel Effectors (CRANE) seeks "... to design, build, and flight test a novel X-plane that incorporates active flow control (AFC) as a primary design consideration. ... In 2023, the aircraft received its official designation as X-65." In January 2024, construction began, at Boeing subsidiary Aurora Flight Sciences. According to DARPA, the Aurora X-65 could be completed and unveiled as soon as early 2025, with the first flight occurring in summer 2025. In circulation control, near the trailing edges of wings, aircraft flight control systems are replaced by slots which emit fluid flows. == List of stealth aircraft == F-117 Nighthawk B-2 Spirit F-22 Raptor F-35 Lightning II J-20 Su-57 B-21 Raider FC-31 Su-75 Checkmate == List of stealth helicopters == Boeing–Sikorsky RAH-66 Comanche Hughes 500P == List of reduced-signature ships == Navy ships worldwide have incorporated signature-reduction features, mostly for the purpose of reducing anti-ship missile detection range and enhancing countermeasure effectiveness rather than actual detection avoidance. Such ships include: Bhumibol Adulyadej-class frigate Independence-class littoral combat ship Kamorta-class corvette Klewang-class fast attack craft Kolkata-class destroyer La Fayette-class frigate Nilgiri-class frigate Sachsen-class frigate Shahid Soleimani-class corvette Shivalik-class frigate Skjold-class corvette Talwar-class frigate Tuo Chiang-class corvette Type 055 destroyer Visakhapatnam-class destroyer Visby-class corvette Zumwalt-class destroyer == See also == Active camouflage Multi-spectral camouflage Cloaking device Penetration aid == References == === Bibliography === "How "stealth" is achieved on F-117A". aeronautics.ru. Archived from the original on 20 February 2002. Dawson, T. W. G.; Kitchen, G. F.; Glider, G. B. (September 1957). Measurements of the Radar Echoing Area of the Vulcan by the Optical Simulation Method. Farnborough, Hants, UK: Royal Aircraft Establishment. National Archive Catalogue file, AVIA 6/20895 Doucet, Arnaud; Freitas, Nando de; Gordon, Neil (2001) [2001]. Sequential Monte Carlo Methods in Practice. Statistics for Engineering and Information Science (1st ed.). Berlin: Springer-Verlag. ISBN 978-0-387-95146-1. Retrieved 11 March 2009. Gal-Or, Benjamin (1990). "Multiaxis Thrust Vectoring Flight Control vs Catastrophic Failure Prevention". Vectored Propulsion, Supermanoeuvreability, and Robot Aircraft. Reports to U.S. Dept. of Transportation/FAA, Technical Center, ACD-210, FAA X88/0/6FA/921000/4104/T1706D, FAA Res. Grant-Award No: 94-G-24, CFDA, No. 20.108, 26 December 1994. Springer Verlag. ISBN 0-387-97161-0. and 3-540-97161-0. Haffa, Robert P. Jr.; Patton, James H. Jr. (June 2002). "Analogues of Stealth" (PDF). Analysis Center Papers. Northrop Grumman. Archived from the original (PDF) on 12 August 2012. Suhler, Paul A. (2009). From Rainbow to Gusto: Stealth and the Design of the Lockheed Blackbird. American Institute of Aeronautics and Astronautics. ISBN 978-1-60086-712-5. Ufimtsev, Pyotr Ya. (1962). Method of edge waves in the physical theory of diffraction. Moscow, Russia: Izd-vo. Sov. Radio [Soviet Radio Publishing]. pp. 1–243. United States Patent No.6,297,762. 2 October 2001. Electronic countermeasures system (Apparatus for detecting the difference in phase between received signals at two spaced antennas and for then retransmitting equal amplitude antiphase signals from the two spaced antennas is disclosed.) Yue, Tao (30 November 2001). "Scouting For Surveillance: Detection of the B-2 Stealth Bomber And a Brief History on "Stealth"". The Tech. 121 (63). Archived from the original on 6 March 2009. == External links == Stealth design used for military aircraft? A Stealth Satellite Sourcebook Stealth in strike warfare Stealth technology The Paradigm Shift in Air Superiority (Stealth)
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Anna University is a public state university located in Chennai, Tamil Nadu, India. The main campus is in Guindy. It was originally established on 4 September 1978 and is named after C. N. Annadurai, former Chief Minister of Tamil Nadu. == History and structure == Anna University (Chennai) comprises four colleges - the principal seat College of Engineering, Guindy (CEG, Guindy Campus), Alagappa College of Technology (ACT, Guindy Campus), Madras Institute of Technology (MIT, Chromepet Campus) and School of Architecture and Planning (SAP, Guindy Campus). The first version of Anna University was formed in 1978 and various governments changed the varsity's structure and affiliation scope repeatedly. In 2001, under the Anna University Amendment Act of 2001, the erstwhile Anna University became an affiliating university, taking under its wings all the engineering colleges in Tamil Nadu. This included six government engineering colleges, three government-aided private institutions, and 426 self-financed colleges. On 1 February 2007, as a result of a Government of Tamil Nadu decision, the university was split into six constituent universities: Anna University, Chennai; Anna University of Technology, Chennai; Anna University of Technology, Tiruchirappalli; Anna University of Technology, Coimbatore; Anna University of Technology Tirunelveli and Anna University of Technology, Madurai. The institutes were formally created in 2010. On 14 September 2011 during period of Ex CM Jayalalithaa, a bill was passed to re-merge the universities. The merger was finalized in August 2012. In 2011 and 2012 the constituents colleges were merged back to a single affiliating university and the four regional universities continue to function as a regional campus of the university. === School of Architecture and Planning === The School of Architecture and Planning was established as a Department of Architecture of the University of Madras in 1957 and was located in the Alagappa College of Technology. The department was later renamed as the School of Architecture and Planning and shifted to its own independent campus in 1968. It became a constituent college of the University at its founding. It started to functions as two departments namely Department of Architecture and Department of Planning from 2005 till date. SAP has a Centre for Human Settlements (CHS) which is an autonomous Centre of the Anna University that was established in 1980. It is an interdisciplinary Centre offering Consultancy, Training, Research and Extension services in the areas related to Urban and Regional Planning, Development and Management. The Quality Improvement Program (QIP) Cell was established by the AICTE at SAP campus and has provided the research facilities for teachers of other architectural institutions besides providing admission to PG degree course. == Admissions == A common entrance test – the Tamil Nadu Professional Courses Entrance Examination (TNPCEE) – was used as a basis for admission to professional courses in the state until 2006. Starting in the academic year 2007–08, students were admitted to engineering colleges on the basis of their higher secondary marks. Post-graduate admission process is carried out through TANCET and GATE scores. == Academics == The university offers courses in engineering and technology through its affiliated colleges and follows a dual semester system. Every year the university conducts examinations for the even semester in May–June and for an odd semester in November–December. === Rankings === Internationally, Anna University was ranked under 1000 in the QS World University Rankings & Times Higher Education World University Rankings in 2023. In the 2024 National Institutional Ranking Framework, Anna University was ranked 20th overall and 13th among universities in India. Additionally, it secured the 14th position in the Engineering category and the 69th in the Management category. == Incidents == === Sexual assault incident === On December 25, 2024, a second-year female engineering student at Anna University was sexually assaulted by two men inside the campus. The incident took place in the early hours of the morning after the survivor and her male friend returned from a Christmas mass at a nearby church. The two students were sitting in a secluded area of the campus when the assailants attacked the male student and then proceeded to sexually assault the woman. The survivor immediately filed a police complaint, and a case was registered under Section 64 of the BNSS (rape). The perpetrator was arrested and detained under the Tamil Nadu Goondas act and was lodged into Puzhal prison. == Affiliated colleges == The university's campus is in Chennai. The university has satellite campuses in Coimbatore, Tiruchirappalli, Madurai and Tirunelveli. The university also runs engineering colleges at Villupuram, Tindivanam, Arani and Kanchipuram in Chennai region, Erode and Bargur in Coimbatore region, Panruti, Pattukkottai, Thirukkuvalai and Ariyalur in Tiruchirapalli region, Ramanathapuram and Dindigul in Madurai region, Nagercoil and Thoothukudi in Tirunelveli region. == Notable Alumni == A Lalitha, first female engineer from India A. C. Muthiah, Indian industrialist and former Board of Control for Cricket in India president Nagarjuna, Telugu film actor Anumolu Ramakrishna, deputy managing director of Larsen & Toubro Crazy Mohan, Tamil comedy actor, script writer and playwright Kavithalaya Krishnan Indian film and television actor Dhiraj Rajaram, founder & chairman of Mu Sigma Inc Gopalaswami Parthasarathy, former Indian High Commissioner to Pakistan, Australia and Myanmar and Chancellor, Central University of Jammu Kanuri Lakshmana Rao, architect of India's water management, Former Union Minister of Irrigation & Power and recipient of the Padma Bhushan Krishnakumar Natarajan, co-founder & former executive chairman of Mindtree Krishnamachari Srikkanth, former Indian cricket captain and former chairman, National Selection Committee of the Indian Cricket Team Kutraleeswaran, long-distance swimmer and Guinness Book of World Records holder Madhan Karky, Tamil film lyricist Mendu Rammohan Rao, former dean emeritus, Indian School of Business Munirathna Anandakrishnan, former chairman, Indian Institute of Technology, Kanpur and former vice-chancellor, Anna University N. Mahalingam, founder & former chairman, Sakthi Group and former chairman, Ethiraj College for Women P. S. Veeraraghavan, director of Vikram Sarabhai Space Centre R. K. Baliga, developer of the Electronics City in Bangalore, India P. V. Nandhidhaa, Indian chess player, India's 17th Woman Grandmaster. Ponnambalam "Poondi" Kumaraswamy, engineer, mathematician, and hydrologist Raj Reddy, Turing Award winner, professor at Carnegie-Mellon University and Padma Bhushan recipient Rajkumar Bharathi, classical singer and music composer Rangaswamy Narasimhan, cognitive scientist who developed TIFRAC, the first indigenous Indian computer, Padma Shri winner Ravi Ruia, vice chairperson & co-founder of Essar Group S. Somasegar, former senior vice president, Microsoft Srinivasaraghavan Venkataraghavan, former cricket captain and ICC Elite Umpires Panel member Upendra J. Chivukula, former New Jersey General Assembly member V. M. Muralidharan, chairman, Ethiraj College for Women J. Sai Deepak, lawyer in the Supreme Court of India V. S. Mahalingam, DRDO scientist and director of the Centre for Artificial Intelligence and Robotics Venu Srinivasan, chairman of Sundaram - Clayton Limited and TVS Motor Company Verghese Kurien, architect of Operation Flood and India's White Revolution and recipient of the Padma Vibhushan, Ramon Magsaysay Award and the World Food Prize M. Madan Babu , director at St. Jude Children's Research Hospital Sundaram Karivardhan, industrialist and motorsport pioneer A. G. Ramakrishnan, professor, Indian Institute of Science Mahesh Muthuswami, Cinema tog 2012 == See also == List of Colleges & Institutions affiliated to Anna University Excel Group Institutions == References == == External links == Official website Architecture
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https://en.wikipedia.org/wiki/Anna_University
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