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https://en.wikipedia.org/wiki/Von%20Neumann%20entropy
In physics, the von Neumann entropy, named after John von Neumann, is an extension of the concept of Gibbs entropy from classical statistical mechanics to quantum statistical mechanics. For a quantum-mechanical system described by a density matrix , the von Neumann entropy is where denotes the trace and ln denotes the (natural) matrix logarithm. If the density matrix is written in a basis of its eigenvectors as then the von Neumann entropy is merely In this form, S can be seen as the information theoretic Shannon entropy. The von Neumann entropy is also used in different forms (conditional entropies, relative entropies, etc.) in the framework of quantum information theory to characterize the entropy of entanglement. Background John von Neumann established a rigorous mathematical framework for quantum mechanics in his 1932 work Mathematical Foundations of Quantum Mechanics. In it, he provided a theory of measurement, where the usual notion of wave-function collapse is described as an irreversible process (the so-called von Neumann or projective measurement). The density matrix was introduced, with different motivations, by von Neumann and by Lev Landau. The motivation that inspired Landau was the impossibility of describing a subsystem of a composite quantum system by a state vector. On the other hand, von Neumann introduced the density matrix in order to develop both quantum statistical mechanics and a theory of quantum measurements. The density matrix formalism,
https://en.wikipedia.org/wiki/Copper%28I%29%20thiophene-2-carboxylate
Copper(I) thiophene-2-carboxylate or CuTC is a coordination complex derived from copper and thiophene-2-carboxylic acid. It is used as a reagent to promote the Ullmann reaction between aryl halides. References Thiophenes Copper(I) compounds Reagents for organic chemistry
https://en.wikipedia.org/wiki/Structural%20stability
In mathematics, structural stability is a fundamental property of a dynamical system which means that the qualitative behavior of the trajectories is unaffected by small perturbations (to be exact C1-small perturbations). Examples of such qualitative properties are numbers of fixed points and periodic orbits (but not their periods). Unlike Lyapunov stability, which considers perturbations of initial conditions for a fixed system, structural stability deals with perturbations of the system itself. Variants of this notion apply to systems of ordinary differential equations, vector fields on smooth manifolds and flows generated by them, and diffeomorphisms. Structurally stable systems were introduced by Aleksandr Andronov and Lev Pontryagin in 1937 under the name "systèmes grossiers", or rough systems. They announced a characterization of rough systems in the plane, the Andronov–Pontryagin criterion. In this case, structurally stable systems are typical, they form an open dense set in the space of all systems endowed with appropriate topology. In higher dimensions, this is no longer true, indicating that typical dynamics can be very complex (cf. strange attractor). An important class of structurally stable systems in arbitrary dimensions is given by Anosov diffeomorphisms and flows. During the late 1950s and the early 1960s, Maurício Peixoto and Marília Chaves Peixoto, motivated by the work of Andronov and Pontryagin, developed and proved Peixoto's theorem, the first global ch
https://en.wikipedia.org/wiki/Generation%20of%20primes
In computational number theory, a variety of algorithms make it possible to generate prime numbers efficiently. These are used in various applications, for example hashing, public-key cryptography, and search of prime factors in large numbers. For relatively small numbers, it is possible to just apply trial division to each successive odd number. Prime sieves are almost always faster. Prime sieving is the fastest known way to deterministically enumerate the primes. There are some known formulas that can calculate the next prime but there is no known way to express the next prime in terms of the previous primes. Also, there is no effective known general manipulation and/or extension of some mathematical expression (even such including later primes) that deterministically calculates the next prime. Prime sieves A prime sieve or prime number sieve is a fast type of algorithm for finding primes. There are many prime sieves. The simple sieve of Eratosthenes (250s BCE), the sieve of Sundaram (1934), the still faster but more complicated sieve of Atkin (2003), and various wheel sieves are most common. A prime sieve works by creating a list of all integers up to a desired limit and progressively removing composite numbers (which it directly generates) until only primes are left. This is the most efficient way to obtain a large range of primes; however, to find individual primes, direct primality tests are more efficient. Furthermore, based on the sieve formalisms, some integer s
https://en.wikipedia.org/wiki/Subbundle
In mathematics, a subbundle of a vector bundle on a topological space is a collection of linear subspaces of the fibers of at in that make up a vector bundle in their own right. In connection with foliation theory, a subbundle of the tangent bundle of a smooth manifold may be called a distribution (of tangent vectors). If a set of vector fields span the vector space and all Lie commutators are linear combinations of the then one says that is an involutive distribution. See also Fiber bundles
https://en.wikipedia.org/wiki/Emerson%20C.%20Itschner
Emerson Charles Itschner (July 1, 1903 – March 15, 1995) was an American military engineer. Biography Emerson C. Itschner was born in Chicago on July 1, 1903. He graduated from the United States Military Academy in 1924 and was commissioned in the Corps of Engineers. He obtained a degree in civil engineering from Cornell University in 1926. Itschner served with the Alaska Road Commission in 1927–1929. He taught at the Missouri School of Mines and served as assistant to the Upper Mississippi Valley Division Engineer and the St. Louis District Engineer. He commanded a topographic survey company in 1940–1941. In 1942–1943 Itschner headed the office in Corps headquarters that supervised Army airfield construction in the 48 states. In 1944–1945 he oversaw the reconstruction of ports and the development of supply routes to U.S. forces in Europe as Engineer, ADSEC (Advance Section, Communications Zone). Itschner headed the division in Corps headquarters responsible for military construction operations from 1946 to 1949. After a year as Seattle District Engineer, he went to Korea as Engineer of I Corps and oversaw engineer troop operations in western Korea. He was North Pacific Division Engineer in 1952–1953. From 1953 until being appointed Chief of Engineers, he served as Assistant Chief of Engineers for Civil Works. General Itschner retired in 1961. He died in Portland, Oregon, on March 15, 1995. The Itschner Award is given each year by the Society of American Military Enginee
https://en.wikipedia.org/wiki/Glauber
Glauber is a scientific discovery method written in the context of computational philosophy of science. It is related to machine learning in artificial intelligence. Glauber was written, among other programs, by Pat Langley, Herbert A. Simon, G. Bradshaw and J. Zytkow to demonstrate how scientific discovery may be obtained by problem solving methods, in their book Scientific Discovery, Computational Explorations on the Creative Mind. Their programs simulate historical scientific discoveries based on the empirical evidence known at the time of discovery. Glauber was named after Johann Rudolph Glauber, a 17th-century alchemist whose work helped to develop acid-base theory. Glauber (the method) rediscovers the law of acid-alkali reactions producing salts, given the qualities of substances and observed facts, the result of mixing substances. From that knowledge Glauber discovers that substances that taste bitter react with substances tasting sour, producing substances tasting salty. In few words, the law: Acid + Alkali --> Salt Glauber was designed by Pat Langley as part of his work on discovery heuristics in an attempt to have a computer automatically review a host of values and characteristics and make independent analyses from them. In the case of Glauber, the goal was to have an autonomous application that could estimate, even perfectly describe, the nature of a given chemical compound by comparing it to related substances. Langley formalized and compiled Glauber in 1
https://en.wikipedia.org/wiki/Virtutech
Virtutech was a company founded in 1998 as a spin-off from the Swedish Institute of Computer Science (SICS), to commercially develop its Simics computer architecture simulator software. In 2004, Virtutech accepted investment and moved headquarters to San Jose, California, USA. In 2010, Virtutech was wholly acquired by Intel and became part of Intel's Wind River subsidiary. In 2018, Wind River was sold to TPG Capital, which continues to sell Simics under the Wind River brand. The Intel Stockholm site remains the center of Simics core R&D. Simics software is used by teams of software developers to simulate computer systems. This facilitates the development, testing, and debugging of embedded software that runs devices such as high-end servers, network hardware, aerospace/military vehicles, and automobiles. Simics allows embedded software developers to create virtual models of hardware using an ordinary desktop computer, run specified sets of tests, and walk the programs through each step of execution, both forwards and backwards. History In 2001, AMD and Virtutech began working collaboratively on simulation for AMD's Hammer chips. In July 2005, IBM selected Virtutech Simics for development of its POWER6 platform. In 2007, Virtutech and Freescale announced a collaboration program around multicore processors. Virtutech thus appears to have a customer base that is partly in the embedded software world, and partly in the general computing and server world. Virtutech was a memb
https://en.wikipedia.org/wiki/Electromagnetic%20electron%20wave
In plasma physics, an electromagnetic electron wave is a wave in a plasma which has a magnetic field component and in which primarily the electrons oscillate. In an unmagnetized plasma, an electromagnetic electron wave is simply a light wave modified by the plasma. In a magnetized plasma, there are two modes perpendicular to the field, the O and X modes, and two modes parallel to the field, the R and L waves. Waves in an unmagnetized plasma Langmuir Wave The Langmuir wave is a purely longitudinal wave, that is, the wave vector is in the same direction as the E-field. It is an electrostatic wave; as such, it doesn't have an oscillating magnetic field. A plasma consists of charged particles which react to electric fields, in contrast with dielectric matter. When electrons in a uniform, homogeneous plasma are perturbed from their equilibrium position, a charge separation occurs creating an electric field which acts as restoring force on the electrons. Since electrons have inertia the system behaves as a harmonic oscillator, where the electrons oscillate at a frequency ωpe, called electron plasma frequency. These oscillations do not propagate -- the group velocity is 0. When the thermal motion of the electrons is taken into account a shift in frequency from the electron plasma frequency ωpe occurs. Now the electron pressure gradient acts as the restoring force, creating a propagating wave analogous to a sound wave in non-ionized gases. Combining these two restoring forces
https://en.wikipedia.org/wiki/Heawood%20number
In mathematics, the Heawood number of a surface is an upper bound for the number of colors that suffice to color any graph embedded in the surface. In 1890 Heawood proved for all surfaces except the sphere that no more than colors are needed to color any graph embedded in a surface of Euler characteristic , or genus for an orientable surface. The number became known as Heawood number in 1976. Franklin proved that the chromatic number of a graph embedded in the Klein bottle can be as large as , but never exceeds . Later it was proved in the works of Gerhard Ringel, J. W. T. Youngs, and other contributors that the complete graph with vertices can be embedded in the surface unless is the Klein bottle. This established that Heawood's bound could not be improved. For example, the complete graph on vertices can be embedded in the torus as follows: The case of the sphere is the four-color conjecture, which was settled by Kenneth Appel and Wolfgang Haken in 1976. Notes Béla Bollobás, Graph Theory: An Introductory Course, Graduate Texts in Mathematics, volume 63, Springer-Verlag, 1979. . Thomas L. Saaty and Paul Chester Kainen; The Four-Color Problem: Assaults and Conquest, Dover, 1986. . References Topological graph theory Graph coloring
https://en.wikipedia.org/wiki/Star%20product
In mathematics, the star product is a method of combining graded posets with unique minimal and maximal elements, preserving the property that the posets are Eulerian. Definition The star product of two graded posets and , where has a unique maximal element and has a unique minimal element , is a poset on the set . We define the partial order by if and only if: 1. , and ; 2. , and ; or 3. and . In other words, we pluck out the top of and the bottom of , and require that everything in be smaller than everything in . Example For example, suppose and are the Boolean algebra on two elements. Then is the poset with the Hasse diagram below. Properties The star product of Eulerian posets is Eulerian. See also Product order, a different way of combining posets References Stanley, R., Flag -vectors and the -index, Math. Z. 216 (1994), 483-499. Combinatorics
https://en.wikipedia.org/wiki/Pluriharmonic%20function
In mathematics, precisely in the theory of functions of several complex variables, a pluriharmonic function is a real valued function which is locally the real part of a holomorphic function of several complex variables. Sometimes such a function is referred to as n-harmonic function, where n ≥ 2 is the dimension of the complex domain where the function is defined. However, in modern expositions of the theory of functions of several complex variables it is preferred to give an equivalent formulation of the concept, by defining pluriharmonic function a complex valued function whose restriction to every complex line is a harmonic function with respect to the real and imaginary part of the complex line parameter. Formal definition . Let be a complex domain and be a (twice continuously differentiable) function. The function is called pluriharmonic if, for every complex line formed by using every couple of complex tuples , the function is a harmonic function on the set . Let be a complex manifold and be a function. The function is called pluriharmonic if Basic properties Every pluriharmonic function is a harmonic function, but not the other way around. Further, it can be shown that for holomorphic functions of several complex variables the real (and the imaginary) parts are locally pluriharmonic functions. However a function being harmonic in each variable separately does not imply that it is pluriharmonic. See also Plurisubharmonic function Wirtinger derivatives N
https://en.wikipedia.org/wiki/Pluripolar%20set
In mathematics, in the area of potential theory, a pluripolar set is the analog of a polar set for plurisubharmonic functions. Definition Let and let be a plurisubharmonic function which is not identically . The set is called a complete pluripolar set. A pluripolar set is any subset of a complete pluripolar set. Pluripolar sets are of Hausdorff dimension at most and have zero Lebesgue measure. If is a holomorphic function then is a plurisubharmonic function. The zero set of is then a pluripolar set. See also Skoda-El Mir theorem References Steven G. Krantz. Function Theory of Several Complex Variables, AMS Chelsea Publishing, Providence, Rhode Island, 1992. Potential theory
https://en.wikipedia.org/wiki/Tim%20Jarvis
Tim Jarvis AM (born May 1966) is a British-Australian environmental explorer, adventurer, climber, author and documentary filmmaker, with Masters qualifications in environmental science and environmental law. Due to his 2013 expedition recreating the voyage and mountain crossing of Sir Ernest Shackleton, Jarvis is considered an authority on Shackleton and the leadership style he espoused. Tim Jarvis is well-known public speaker who presents regularly around the world. He formerly worked as a Senior Associate – Sustainability to engineering firm Arup, and has also advised the World Bank, AusAID, and the Asian Development Bank on multilateral aid projects. His environmental work is mainly focused on climate change, sustainable aid provision in developing countries, and improving corporate environmental sustainability, as well as 'significant project' management through his project 25zero, which uses equatorial glacial melt as an indicator of global climate change, and the ForkTree Project, which aims to rewild an area of degraded farmland. Since 2019, Jarvis has lobbied to establish an East Antarctic Marine Protected Area together with Save Our Marine Life (an alliance of leading conservation organisations) and the Pew Charitable Trust. Jarvis authored the forward to the report The East Antarctic Marine Park: Maintaining Australia's Legacy, produced in 2019. Jarvis says he is "committed to finding pragmatic solutions to global environmental sustainability issues", and as a
https://en.wikipedia.org/wiki/Plurisubharmonic%20function
In mathematics, plurisubharmonic functions (sometimes abbreviated as psh, plsh, or plush functions) form an important class of functions used in complex analysis. On a Kähler manifold, plurisubharmonic functions form a subset of the subharmonic functions. However, unlike subharmonic functions (which are defined on a Riemannian manifold) plurisubharmonic functions can be defined in full generality on complex analytic spaces. Formal definition A function with domain is called plurisubharmonic if it is upper semi-continuous, and for every complex line with the function is a subharmonic function on the set In full generality, the notion can be defined on an arbitrary complex manifold or even a complex analytic space as follows. An upper semi-continuous function is said to be plurisubharmonic if and only if for any holomorphic map the function is subharmonic, where denotes the unit disk. Differentiable plurisubharmonic functions If is of (differentiability) class , then is plurisubharmonic if and only if the hermitian matrix , called Levi matrix, with entries is positive semidefinite. Equivalently, a -function f is plurisubharmonic if and only if is a positive (1,1)-form. Examples Relation to Kähler manifold: On n-dimensional complex Euclidean space , is plurisubharmonic. In fact, is equal to the standard Kähler form on up to constant multiples. More generally, if satisfies for some Kähler form , then is plurisubharmonic, which is called Kähl
https://en.wikipedia.org/wiki/AS%201100
AS 1100 is an Australian Standard for technical drawing including both mechanical and architectural designs. AS 1100 standard drawings contain attributes that are universal around Australia. The standard is published by Standards Australia. The standard consists of five parts, Part 101: General principles (1992) Part 201: Mechanical engineering drawing (1992) Part 301: Architectural drawing (2008) Part 401: Engineering survey and engineering survey design drawing (1984) Part 501: Structural engineering drawing (2002) References Building engineering Architectural communication Standards of Australia
https://en.wikipedia.org/wiki/384%20%28number%29
384 (three hundred [and] eighty-four) is the natural number following 383 and preceding 385. It is an even composite positive integer. In mathematics 384 is: the sum of a twin prime pair (191 + 193). the sum of six consecutive primes (53 + 59 + 61 + 67 + 71 + 73). the order of the hyperoctahedral group for n = 4 the double factorial of 8. an abundant number. the third 129-gonal number after 1, 129 and before 766 and 1275. a Harshad number in bases 2, 3, 4, 5, 7, 8, 9, 13, 17, and 62 other bases. a refactorable number. Computing Being a low multiple of a power of two, 384 occurs often in the field of computing. For example, the digest length of the secure hash function SHA-384, the screen resolution of Virtual Boy is 384x224, MP3 Audio layer 1 encoding is 384 kibps, in 3G phones the WAN implementation of CDMA is up to 384 kbit/s. References External links Integers
https://en.wikipedia.org/wiki/Heredity%20%28disambiguation%29
Heredity may refer to: Heredity: the transfer of characteristics from parent to offspring Inheritance: the hereditary transfer of titles, property, or assets from parent to offspring (or other beneficiary) A synonym for bloodline; for other uses of the term, see Bloodline (disambiguation) Hereditary property, in mathematics, a property of objects inherited by all their subobjects Heredity (journal), a scientific journal "Heredity" (short story), a science fiction story by Isaac Asimov Heredity (film), a 1912 film starring Harry Carey Hereditary (film), a 2018 film starring Toni Collette Heredity (album), a 1985 album by Rational Youth
https://en.wikipedia.org/wiki/Angewandte%20Chemie
Angewandte Chemie (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the Journal Citation Reports, the journal had a 2021 impact factor of 16.823. Editions The journal appears in two editions with separate volume and page numbering: a German edition, Angewandte Chemie ( (print), (online)), and a fully English-language edition, Angewandte Chemie International Edition ( (print), (online)). The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Business model Angewandte Chemie is available online and in print. It is a hybrid open access journal and authors may choose to pay a fee to make articles available free of charge. Angewandte Chemie provides free access to supporting information. Publication history In 1887, Ferdinand Fischer founded the Zeitschrift für die Chemische Industrie (Journal for the Chemical Industry). In 1888, the title was changed to Zeitschrift für Angewandte Chemie (Journal of Applied Chemistry), and volume numbering started over. This title was kept
https://en.wikipedia.org/wiki/Ramon%20Margalef
Ramon Margalef i López (Barcelona 16 May 1919 - 23 May 2004) was a Spanish biologist and ecologist. He was Emeritus Professor of Ecology at the Faculty of Biology of the University of Barcelona. Margalef, one of the most prominent scientists that Spain has produced, worked at the Institute of Applied Biology (1946–1951), and at the Fisheries Research Institute, which he directed during 1966–1967. He created the Department of Ecology of the University of Barcelona, from where he trained a huge number of ecologists, limnologists and oceanographers. In 1967 he became Spain's first professor of ecology. Career summary From 1954 to 1974 Margalef contributed to the New York-based magazine Iberica. In 1957, with the translation into English of his inaugural lecture as a member of the Barcelona Royal Academy of Arts and Sciences, "Information Theory in Ecology", he gained a worldwide audience. Another groundbreaking article, "On certain unifying principles in ecology", published in American Naturalist in 1963, and his book "Perspectives in Ecological Theory" (1968), based on his guest lectures at the University of Chicago, consolidated him as one of the leading thinkers of modern ecology. In the summer of 1958 he was professor of Marine ecology at the Institute of Marine Biology (currently Department of Marine Sciences) of the University of Puerto Rico at Mayagüez and produced the work ("Natural Communities"). Some of his most important work includes the application of informatio
https://en.wikipedia.org/wiki/Holger%20Bech%20Nielsen
Holger Bech Nielsen (born 25 August 1941) is a Danish theoretical physicist and professor emeritus at the Niels Bohr Institute, at the University of Copenhagen, where he started studying physics in 1961. Work Nielsen has made original contributions to theoretical particle physics, specifically in the field of string theory. Independently of Nambu and Susskind, he was the first to propose that the Veneziano model was actually a theory of strings, leading him to be considered among the fathers of string theory. He was awarded the Humboldt Prize in 2001 for his research. Several physics concepts are named after him, e.g. Nielsen–Olesen vortex and the Nielsen-Ninomiya no-go theorem for representing chiral fermions on the lattice. In the original Dual-Models, which later would be recognized as the origins of string theory, the Koba-Nielsen variables are also named after him and his collaborator Ziro Koba. Nielsen is known in Denmark for his enthusiastic public lectures on physics and string theory, and he is often interviewed in daily news, especially on matters regarding particle physics. In a series of papers uploaded to arXiv.org in 2009, Nielsen and fellow physicist Masao Ninomiya proposed a radical theory to explain the seemingly improbable series of failures preventing the Large Hadron Collider (LHC) from becoming operational. The collider was intended to be used to find evidence of the hypothetical Higgs boson particle. They suggested that the particle might be so abhorr
https://en.wikipedia.org/wiki/Michael%20D.%20Gershon
Dr. Michael D. Gershon is the author of The Second Brain and the chairman of the department of anatomy and cell biology at Columbia University. See also Ulcerative colitis Enteric nervous system Myenteric plexus External links Research summary page of Columbia University The Other Brain Also Deals With Many Woes, New York Times, 23 August 2005 Living people 1938 births Place of birth missing (living people) Columbia University faculty
https://en.wikipedia.org/wiki/Environmental%20medicine
Environmental medicine is a multidisciplinary field involving medicine, environmental science, chemistry and others, overlapping with environmental pathology. It can be viewed as the medical branch of the broader field of environmental health. The scope of this field involves studying the interactions between environment and human health, and the role of the environment in causing or mediating disease. This specialist field of study developed after the realisation that health is more widely and dramatically affected by environmental factors than previously recognized. Environmental factors in the causation of environmental diseases can be classified into: Physical Chemical Biological Social (including Psychological and Culture variables) Ergonomic Safety Any combination of the above In the United States, the American College of Occupational and Environmental Medicine (OCOEM) oversees board certification of physicians in environmental (and occupational) medicine. This board certification isn't recognized by the American Board of Medical Specialties. Current focuses of environmental medicine While environmental medicine is a broad field, some of the currently prominent issues include: The effects of ozone depletion and the resulting increase in UV radiation on humans with regards to skin cancer. The effects of nuclear accidents or the effects of a terrorist dirty bomb attack and the resulting effects of radioactive material and radiation on humans. The effects of
https://en.wikipedia.org/wiki/Dichlorocarbene
Dichlorocarbene is the reactive intermediate with chemical formula CCl2. Although this chemical species has not been isolated, it is a common intermediate in organic chemistry, being generated from chloroform. This bent diamagnetic molecule rapidly inserts into other bonds. Preparation Dichlorocarbene is most commonly generated by reaction of chloroform and a base such as potassium tert-butoxide or aqueous sodium hydroxide. A phase transfer catalyst, for instance benzyltriethylammonium bromide, facilitates the migration of the hydroxide in the organic phase. HCCl3 + NaOH → CCl2 + NaCl + H2O Other reagents and routes Another precursor to dichlorocarbene is ethyl trichloroacetate. Upon treatment with sodium methoxide it releases CCl2. Phenyl(trichloromethyl)mercury decomposes thermally to release CCl2. PhHgCCl3 → CCl2 + PhHgCl Dichlorodiazirine, which is stable in the dark, decomposes into dichlorocarbene and nitrogen via photolysis. Dichlorocarbene can also be obtained by dechlorination of carbon tetrachloride with magnesium with ultrasound chemistry. This method is tolerant to esters and carbonyl compounds because it does not involve strong base. Reactions With alkenes Dichlorocarbene reacts with alkenes in a formal [1+2]cycloaddition to form geminal dichlorocyclopropanes. These can be reduced to cyclopropanes or hydrolysed to give cyclopropanones by a geminal halide hydrolysis. Dichlorocyclopropanes may also be converted to allenes in the Skattebøl rearrangement. Wit
https://en.wikipedia.org/wiki/Rudolf%20Zahradn%C3%ADk
Rudolf Zahradník (20 October 192831 October 2020) was a Czech chemist in the field of quantum chemistry and molecular spectroscopy. He held research positions at the Institute of Occupational Medicine and went on to serve as the first director of the J Heyrovsky Institute of Physical Chemistry, president of the Czech Academy of Sciences and chairman of the Learned Society of the Czech Republic, after the Velvet Revolution. During the 1980s, he taught future German leader Angela Merkel, who was then on an internship in Czechoslovakia. He held a doctorate from the University of Chemistry and Technology, Prague. Early life and career Zahradník was born in Bratislava (then in Czechoslovakia, now in Slovakia) on 20 October 1928. He was a member of the Junák scout movement and decided to study chemistry when he read an article on invisible ink at grammar school. He graduated from the University of Chemistry and Technology, Prague in 1952, one of his teachers there was Jaroslav Koutecký. Four years later he obtained a Ph.D. in chemistry from the same university. Having previously been considered a bad influence on his students, Zahradník was able to obtain a research position after the Khrushchev Thaw relaxed Soviet restrictions on Czechoslovakia. He studied the relations between chemical structure and biological activity at the Institute of Occupational Medicine and theory of chemical reactivity and molecular spectroscopy at the Institute of Physical Chemistry of the Czechoslova
https://en.wikipedia.org/wiki/Chow%20variety
In mathematics, particularly in the field of algebraic geometry, a Chow variety is an algebraic variety whose points correspond to effective algebraic cycles of fixed dimension and degree on a given projective space. More precisely, the Chow variety is the fine moduli variety parametrizing all effective algebraic cycles of dimension and degree in . The Chow variety may be constructed via a Chow embedding into a sufficiently large projective space. This is a direct generalization of the construction of a Grassmannian variety via the Plücker embedding, as Grassmannians are the case of Chow varieties. Chow varieties are distinct from Chow groups, which are the abelian group of all algebraic cycles on a variety (not necessarily projective space) up to rational equivalence. Both are named for Wei-Liang Chow(周煒良), a pioneer in the study of algebraic cycles. Background on algebraic cycles If X is a closed subvariety of of dimension , the degree of X is the number of intersection points between X and a generic -dimensional projective subspace of . Degree is constant in families of subvarieties, except in certain degenerate limits. To see this, consider the following family parametrized by t. . Whenever , is a conic (an irreducible subvariety of degree 2), but degenerates to the line (which has degree 1). There are several approaches to reconciling this issue, but the simplest is to declare to be a line of multiplicity 2 (and more generally to attach multiplicities to s
https://en.wikipedia.org/wiki/Horn%20function
In the theory of special functions in mathematics, the Horn functions (named for Jakob Horn) are the 34 distinct convergent hypergeometric series of order two (i.e. having two independent variables), enumerated by (corrected by ). They are listed in . B. C. Carlson revealed a problem with the Horn function classification scheme. The total 34 Horn functions can be further categorised into 14 complete hypergeometric functions and 20 confluent hypergeometric functions. The complete functions, with their domain of convergence, are: while the confluent functions include: Notice that some of the complete and confluent functions share the same notation. References J. Horn Math. Ann. 111, 637 (1933) Hypergeometric functions
https://en.wikipedia.org/wiki/Mol%C4%97tai%20Astronomical%20Observatory
The Molėtai Astronomical Observatory (MAO; Molėtų astronomijos observatorija in Lithuanian) is an astronomical observatory owned and operated by Vilnius University Institute of Theoretical Physics and Astronomy. It is located on the Kaldiniai Hill next to Kulionys, Lithuania, 10 km from the town of Molėtai. History The old astronomical observatory of Vilnius University, opened in 1753, and the new University observatory near Vingis Park, built in 1921, gradually appeared inside the city of Vilnius where conditions turned out to be unsatisfactory for astronomical observations. In 1969, a new observatory was started in the Molėtai district, about 70 km north of Vilnius. It is built on the Kaldiniai Hill just near the small village of Kulionys, about 10 km from the town of Molėtai. In the fall of 1969, the first 25 cm diameter telescope of the Molėtai Astronomical Observatory (MAO) was mounted. Later on, it was placed to the 35/51 cm Maksutov telescope. In 1974 and 1991, the reflecting telescopes of 63 cm and 165 cm diameters were put into operation. Equipment MAO currently has three research telescopes: 35 cm Maksutov telescope (f/3.5), which replaced MAO's first 25 cm telescope in 1975, 63 cm Cassegrain telescope, 165 cm Ritchey–Chrétien telescope, which MAO claims is the largest in Northern Europe (excluding Britain). See also Lithuanian Museum of Ethnocosmology List of largest optical reflecting telescopes References External links Molėtai Observatory Astron
https://en.wikipedia.org/wiki/Nepa%20cinerea
Nepa cinerea is a species of water scorpion (Nepidae), found in most of Europe, including the British Isles, as well as North Africa and southern and northern Asia. Habitat and Biology It lives in ponds, small rivers, and stagnant water, and feeds upon aquatic animals, especially insects. Respiration in the adult is effected by means of the caudal process, which consists of a pair of half-tubes capable of being locked together to form a siphon by means of which air is conducted to the tracheae at the apex of the abdomen when the tip of the tube is thrust above the surface of the water. In immature forms, the siphon is undeveloped and breathing takes place through six pairs of abdominal spiracles. The eggs, laid in the stems of plants, are supplied with seven filamentous processes which float freely in the water. References External links Hemiptera of Europe Insects described in 1758 Articles containing video clips Taxa named by Carl Linnaeus Nepidae
https://en.wikipedia.org/wiki/Hubert%20Lyman%20Clark
Hubert Lyman Clark (January 9, 1870 – July 31, 1947) was an American zoologist. The son of Professor William Smith Clark, he was born at Amherst, Massachusetts, and educated at Amherst College and Johns Hopkins University. From 1899 to 1905 he was professor of biology at Olivet College. Beginning in 1905, Clark worked as assistant in invertebrate zoology at the Museum of Comparative Zoology at Harvard University. He was curator of echinoderms from 1910 to 1927, and curator of marine invertebrates and associate professor of zoology beginning 1927. He was awarded the Clarke Medal by the Royal Society of New South Wales in 1947. Work He carried on scientific investigations in Jamaica, Bermuda and Australia, where he collected in 1913, 1929 and 1932, and published many papers dealing with birds, snakes, echinoderms and flowers. His publications include: The Birds of Amherst and Vicinity (1887) The Echinoderms of Porto Rico (1901) A New Ophiuran from the West Indies (1910) North Pacific Ophiurans in the Collection of the United States National Museum (1911) The echinoderm fauna of Australia (1946) (recording all known species including fossils) He contributed to the New International Encyclopaedia and the Dictionary of American Biography. References External links 1870 births 1947 deaths Amherst College American zoologists Amherst College alumni Johns Hopkins University alumni Harvard University staff Harvard University faculty People from Amherst, Massachusetts Writers
https://en.wikipedia.org/wiki/Ida%20Noddack
Ida Noddack (25 February 1896 – 24 September 1978), née Tacke, was a German chemist and physicist. In 1934 she was the first to mention the idea later named nuclear fission. With her husband Walter Noddack, and Otto Berg, she discovered element 75, rhenium. She was nominated three times for the Nobel Prize in Chemistry. Background Ida Tacke was born in Lackhausen (nowadays a part of the city of Wesel) in the northern Rhine region in 1896. She described how she picked her path of study by stating, "since I did not want to be a teacher at all, and research and industry employed proportionally fewer physicists at that time, I decided to become a chemist– a decision that was welcomed by my father who owned a small varnish factory in the Lower Rhine region." She chose to attend the Technical University of Berlin because she was drawn to its long and demanding programs. She entered the school in 1915, six years after women were allowed to study in all of Berlin's universities. Nine out of the eighty-five members of her class studied chemistry. In 1918, she graduated from the University with a degree in chemical and metallurgical engineering, specifically on higher aliphatic fatty acid anhydrides. She was one of the first women in Germany to study chemistry, and she was a part of one of the first generations of female students in Germany. In addition, the percent of women studying chemistry increased from 3% before World War I to 35% during the war. After graduating, she worked in
https://en.wikipedia.org/wiki/Ohio%20Graduation%20Test
The Ohio Graduation Test (OGT) is the high school graduation examination given to sophomores in the U.S. state of Ohio. Students must pass all five sections (reading, writing, mathematics, science and social studies) in order to graduate. Students have multiple chances to pass these sections and can still graduate without passing each using the alternative pathway. In 2009, the Ohio legislature passed an education reform bill eliminating the OGT in favor of a new assessment system. The development and transition of replacement began in 2014 and will end in 2022. Test History and Development History Prior to the OGT, passing the ninth grade proficiency test was required for graduation beginning with the class of 1994. It had the same five subjects, apart from the social studies test was referred to as the citizenship test. In 2001, the Ohio legislature directed the Ohio Department of Education (ODE) to develop the OGT based on the soon-to-be-adopted academic content standards. The first official OGT was given in March 2005. It replaced the ninth grade proficiency test as a graduation requirement for the class of 2007. The last administration of the ninth grade proficiency test was in 2005. Development Questions are developed by ODE staff, sent through committees, and placed on exams before official inclusion on the OGT. First, the Content Advisory Committee runs the ODE developed question past parents and educators to see if it addresses the content. Second, the Fairness
https://en.wikipedia.org/wiki/Hubert%20Gautier
Henri Gautier, sometimes called Hubert Gautier (21 August 1660 – 27 September 1737) was a French engineer. He was born in Nîmes, France. Career Gautier initially trained as a medical doctor, turning to mathematics and finally engineering. He served as an engineer for 28 years in the province of Languedoc. He was appointed Inspecteur général des ponts et chaussées in 1713, and moved to Paris where he continued working until his retirement in 1731. In 1716, he wrote the first book on building bridges, Traité des ponts. He died in Paris, France at the age of 77. Publications Gautier wrote several published works on engineering, civil engineering and geology. La bibliotheque des philosophes, volumes I-II References French civil engineers Corps des ponts French bridge engineers 1660 births 1737 deaths People from Nîmes
https://en.wikipedia.org/wiki/Marker%20gene
In biology, a marker gene may have several meanings. In nuclear biology and molecular biology, a marker gene is a gene used to determine if a nucleic acid sequence has been successfully inserted into an organism's DNA. In particular, there are two sub-types of these marker genes: a selectable marker and a marker for screening. In metagenomics and phylogenetics, a marker gene is an orthologous gene group which can be used to delineate between taxonomic lineages. Selectable marker A selectable marker protects the organism from a selective agent that would normally kill it or prevent its growth. In a transformation reaction, depending on the transformation efficiency, only one in several million to billion cells may take up DNA. Rather than checking every single cell, scientists use a selective agent to kill all cells that do not contain the foreign DNA, leaving only the desired ones. Antibiotics are the most common selective agents. In bacteria, antibiotics are used almost exclusively. In plants, antibiotics that kill the chloroplast are often used as well, although tolerance to salts and growth-inhibiting hormones is becoming more popular. In mammals, resistance to antibiotics that would kill the mitochondria is used as a selectable marker. Screenable marker A screenable marker will make cells containing the gene look different. There are three types of screening commonly used: Green fluorescent protein makes cells glow green under UV light. A specialized microscope is
https://en.wikipedia.org/wiki/Zeitgeber
A zeitgeber () is any external or environmental cue that entrains or synchronizes an organism's biological rhythms, usually naturally occurring and serving to entrain to the Earth's 24-hour light/dark and 12-month cycles. History The term (; ) was first used by Jürgen Aschoff, one of the founders of the field of chronobiology. His work demonstrated the existence of endogenous (internal) biological clocks, which synchronize biological rhythms. In addition, he found that certain exogenous (external) cues, which he called zeitgeber, influence the timing of these internal clocks. Photic and nonphotic zeitgebers Light (light is a more important zeitgeber than social interactions). Atmospheric conditions Medication Temperature Social interactions Exercise Eating/drinking patterns Circadian rhythms Any biological process in the body that repeats itself over a period of approximately 24 hours and maintains this rhythm in the absence of external stimuli is considered a circadian rhythm. It is believed that the brain's suprachiasmatic nucleus (SCN), or internal pacemaker, is responsible for regulating the body's biological rhythms, influenced by a combination of internal and external cues. To maintain clock-environment synchrony, zeitgebers induce changes in the concentrations of the molecular components of the clock to levels consistent with the appropriate stage in the 24-hour cycle, a process termed entrainment. Early research into circadian rhythms suggested that most p
https://en.wikipedia.org/wiki/Biomedical%20technology
Biomedical technology is the application of engineering and technology principles to the domain of living or biological systems, with an emphasis on human health and diseases. Biomedical engineering and Biotechnology alike are often loosely called Biomedical Technology or Bioengineering. The Biomedical technology field is currently growing at a rapid pace. Biomedical news has often been reported on various platforms, including the MediUnite Journal; and required jobs for the industry expect to grow 23% by 2024, and with the pay averaging over $86,000. Biomedical technology involves: Biomedical science Biomedical informatics Biomedical research Biomedical engineering Bioengineering Biotechnology Biomedical technologies: Cloning Therapeutic cloning References Biological engineering
https://en.wikipedia.org/wiki/Volatility%20%28chemistry%29
In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than highly volatile ones. Differences in volatility can be observed by comparing how fast substances within a group evaporate (or sublimate in the case of solids) when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol (isopropyl alcohol) will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed. In general, solids are much less volatile than liquids, but there are some exceptions. Solids that sublimate (change directly from solid to vapor) such as dry ice (solid carbon dioxide) or iodine can vaporize at a similar rate as some liquids under standard conditions. Description Volatility itself has no defined numerical value, but it is often described using vapor pressures or boiling points (for liquids). High vapor pressures indicate a high volatility, while high boiling points indicate low volatility. Vapor pressures and boiling points are often presented in tables and charts that can be used to compare chemicals of interest. Volatility data is typically found through expe
https://en.wikipedia.org/wiki/Species%20complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), which may be a complex ranking but it is not a species complex. In most cases, a species complex is a monophyletic group of species with a common ancestor, but there are exceptions. It may represent an early stage after speciation in which the species were separated for a long time period without evolving morphological differences. Hybrid speciation can be a component in the evolution of a species complex. Species complexes exist in all groups of organisms and are identified by the rigorous study of differences between individual species that uses minute morphological details, test
https://en.wikipedia.org/wiki/Ernst%20Emil%20Alexander%20Back
Ernst Emil Alexander Back (October 21, 1881 – June 20, 1959) was a German physicist, born in Freiburg. He attended school in Strasbourg until 1900, and from 1902 until 1906 studied law in Strasbourg, Munich, and Berlin. He then worked in the legal profession in Alsace-Lorraine until 1909, afterwards taking leave to study physics in Tübingen. He retired from the legal profession in 1912, and earned his Ph.D. in 1913. His thesis, titled Zur Prestonschen Regel, was on the subject of what would later be called the Paschen-Back effect, and was named after Back and Friedrich Paschen. Between 1914 and 1918 he served with the German Army during World War I. Following this conflict he became head of a Veifa-Werke laboratory in Frankfurt am Main, a company that produced electrical and X-ray equipment. In 1920 he left to become an assistant at the Physics Institute in Tübingen. He was promoted to professor in 1926 at Hohenheim University, and became a full professor in 1929. He remained at this post until 1936 when he returned to become a professor at Tübingen. From 1926 to 1927 Samuel Abraham Goudsmit worked with Back to make the first measurement of nuclear spin and its Zeeman effect. Back retired in 1948, and died in Munich over a decade later. The crater Back on the Moon is named in his memory. External links Biography Further reading 1881 births 1959 deaths 20th-century German physicists
https://en.wikipedia.org/wiki/Abscission
Abscission () is the shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed. In zoology, abscission is the intentional shedding of a body part, such as the shedding of a claw, husk, or the autotomy of a tail to evade a predator. In mycology, it is the liberation of a fungal spore. In cell biology, abscission refers to the separation of two daughter cells at the completion of cytokinesis. In plants Function A plant will abscise a part either to discard a member that is no longer necessary, such as a leaf during autumn, or a flower following fertilisation, or for the purposes of reproduction. Most deciduous plants drop their leaves by abscission before winter, whereas evergreen plants continuously abscise their leaves. Another form of abscission is fruit drop, when a plant abscises fruit while still immature in order to conserve resources needed to bring the remaining fruit to maturity. If a leaf is damaged, a plant may also abscise it to conserve water or photosynthetic efficiency, depending on the 'costs' to the plant as a whole. The abscission layer is a greenish-greyish color. Abscission can also occur in premature leaves as a means of plant defense. Premature leaf abscission has been shown to occur in response to infestation by gall aphids. By abscising leaves that have been made host to aphid galls, plants have been shown to massively diminish the pest population, as 98% of aphids in abscised galls died. The abscission is se
https://en.wikipedia.org/wiki/Azo%20coupling
In organic chemistry, an azo coupling is an organic reaction between a diazonium compound () and another aromatic compound that produces an azo compound (). In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile and the activated carbon (usually from an arene which is called coupling agent) act as a nucleophile. In most cases, including the examples below, the diazonium compound is also aromatic. Diazotization The process of conversion of primary aromatic amines into its diazonium salt is called diazotization. Diazonium salts are important synthetic intermediates that can undergo coupling reactions to form azo dyes and electrophilic substitution reactions to introduce functional groups. Uses of the reaction Aromatic azo compounds tend to be brightly colored due to the extended conjugated systems. Many are used as dyes (see azo dye). Important azo dyes include methyl red and pigment red 170. Azo printing exploits this reaction as well. In this case, the diazonium ion is degraded by light, leaving a latent image in undegraded diazonium salt which is made to react with a phenol, producing a colored image: the blueprint. Prontosil, a first sulfa drug, was once produced by azo coupling. The azo compound is a prodrug that is activated in-vivo to produce the sufanilamide, which is active. The reaction is also used in the Pauly reaction test to detect tyrosine or histidine residues in proteins. Examples of azo C-coupling rea
https://en.wikipedia.org/wiki/David%20P.%20Anderson
David Pope Anderson (born 1955) is an American research scientist at the Space Sciences Laboratory, at the University of California, Berkeley, and an adjunct professor of computer science at the University of Houston. Anderson leads the SETI@home, BOINC, Bossa, and Bolt software projects. Education Anderson received a BA in mathematics from Wesleyan University, and MS and PhD degrees in mathematics and computer science from the University of Wisconsin–Madison. While in graduate school he published four research papers in computer graphics. His PhD research involved using enhanced attribute grammars to specify and implement communication protocols. Career From 1985 to 1992 he was an assistant professor in the UC Berkeley Computer Science Department, where he received the NSF Presidential Young Investigator and IBM Faculty Development awards. During this period he conducted several research projects: FORMULA (Forth Music Language), a parallel programming language and runtime system for computer music based on Forth. MOOD (Musical Object-Oriented Dialect), a parallel programming language and runtime system for computer music based on C++. A port for MS-DOS also exists. DASH, a distributed operating system with support for digital audio and video. Continuous Media File System (CMFS), a file system for digital audio and video Comet, an I/O server for digital audio and video. From 1992 to 1994 he worked at Sonic Solutions, where he developed Sonic System, the first dis
https://en.wikipedia.org/wiki/Christophe%20Bassons
Christophe Bassons (born 10 June 1974) is a French former professional road racing cyclist. His career ended when he spoke out about doping in the Tour de France. Origins Christophe Bassons was born in Mazamet, France, in the Tarn department. He studied and qualified in civil engineering. He began cycle-racing in 1991 in mountain biking. He started racing on the road in 1992 and won the Tour du Tarn et Garonne in 1995. That same year he won the world military time-trial championship and became national time-trial champion. He turned professional in 1996 for Force Sud and then, when the team failed, for Festina, a watch and clock maker. 1998 and Festina Bassons became known during the 1998 Festina doping scandal, when the discovery of a carload of drugs being driven to the team's riders in the Tour de France led to evidence that doping was widespread in the team. In September 1998, the newspaper France Soir published statements made to the police. Two convicted riders, Armin Meier and Christophe Moreau, said that Bassons was the only rider on the team not taking drugs. Jean-Luc Gatellier said in L'Équipe: It's true he's not one of them and he hasn't come out of the same mould. It's true that he refused to 'load the cannon' (the pretty expression used by those who take EPO) these past years, it's true that Christophe Bassons doesn't belong to the family of cheats and the corrupted. Moreau's and Meier's court statement brought attention to a rider who had never acquired it
https://en.wikipedia.org/wiki/Padovan%20polynomials
In mathematics, Padovan polynomials are a generalization of Padovan sequence numbers. These polynomials are defined by: The first few Padovan polynomials are: The Padovan numbers are recovered by evaluating the polynomials Pn−3(x) at x = 1. Evaluating Pn−3(x) at x = 2 gives the nth Fibonacci number plus (−1)n. The ordinary generating function for the sequence is See also Polynomial sequences Polynomials
https://en.wikipedia.org/wiki/Germar%20Rudolf
Germar Rudolf (born 29 October 1964), also known as Germar Scheerer, is a German chemist and a convicted Holocaust denier. Background Rudolf was born in Limburg an der Lahn, Hesse. In 1983 he took his Abitur in Remscheid, then studied chemistry in Bonn, graduating in 1989 with a master's degree. As a student, he joined the A.V. Tuisconia Königsberg zu Bonn and the K.D.St.V. Nordgau Prag zu Stuttgart, Catholic fraternities belonging to the Cartellverband. According to the website “Informationsdienst gegen Rechtsextremismus” (Information service against right-wing extremism), Rudolf was in 1985, a member of Schlesische Jugend (Silesian Youth), the youth section of the association The Landsmannschaft Schlesien - Nieder- und Oberschlesien e.V. ("Territorial Association of Silesia - Lower and Upper Silesia"). Still according to the site Informationsdienst gegen Rechtsextremismus, Rudolf participated the year after, at the Reichsgründungskommers (Reich Foundation Parties) of the ultra-nationalist student association Verein deutscher Studenten (VDSt, German Student League). In 1989, he also took on editorial responsibilities in the German newspaper of New Right Junge Freiheit, and was an author in the far-right journals: Staatsbriefe, Sleipnir, Deutschland in Geschichte und Gegenwart. After supporting the CSU/CDU, he became a member of the Republicans. After his military service with the German Air Force, in October 1990 he joined the Max Planck Institute for Solid State Research a
https://en.wikipedia.org/wiki/Algebra%20Project
The Algebra Project is a national U.S. mathematics literacy program aimed at helping low-income students and students of color achieve the mathematical skills in high school that are a prerequisite for a college preparatory mathematics sequence. Founded by Civil Rights activist and Math educator Bob Moses in the 1980s, the Algebra Project provides curricular materials, teacher training, and professional development support and community involvement activities for schools to improve mathematics education. By 2001, the Algebra Project had trained approximately 300 teachers and was reaching 10,000 students in 28 locations in 10 states. History The Algebra Project was founded in 1982 by Bob Moses in Cambridge, Massachusetts. Moses worked with his daughter's eighth-grade teacher, Mary Lou Mehrling, to provide extra tutoring for several students in her class in algebra. Moses, who had taught secondary school mathematics in New York City and Tanzania, wanted to ensure that those students had sufficient algebra skills to qualify for honors math and science courses in high school. Through his tutorage, students from the Open Program of the Martin Luther King School passed the citywide algebra examination and qualified for ninth grade honors geometry, the first students from the program to do so. The Algebra Project grew out of attempts to recreate this on a wider community level, to provide similar students with a higher level of mathematical literacy. The Algebra Project now focus
https://en.wikipedia.org/wiki/Hydrodynamic%20focusing
In microbiology, hydrodynamic focusing is a technique used to provide more accurate results when using flow cytometers or Coulter counters for determining the size of bacteria or cells. Technique Measuring particles Cells are counted as they are forced to pass through a small channel (often referred to as a flow cell), causing disruptions in a laser light beam or electricity flow. These disruptions are analyzed by the instruments. It is difficult to create tunnels narrow enough for this purpose using ordinary manufacturing processes, as the diameter must be in the magnitude of micrometers, and the length of the tunnel should exceed several millimeters. The standard channel size used in most production flow cytometers is 250 by 250 micrometers. Focusing with a fluid Hydrodynamic focusing solves this problem by building up the walls of the tunnel from fluid, using the effects of fluid dynamics. A wide (hundreds of micrometers in diameter) tube made of glass or plastic is used, through which a "wall" of fluid called the sheath flow is pumped. The sample is injected into the middle of the sheath flow. If the two fluids differ enough in their velocity or density, they do not mix: they form a two-layer stable flow. Sources References Microbiology techniques
https://en.wikipedia.org/wiki/Cauchy%20surface
In the mathematical field of Lorentzian geometry, a Cauchy surface is a certain kind of submanifold of a Lorentzian manifold. In the application of Lorentzian geometry to the physics of general relativity, a Cauchy surface is usually interpreted as defining an "instant of time"; in the mathematics of general relativity, Cauchy surfaces are important in the formulation of the Einstein equations as an evolutionary problem. They are named for French mathematician Augustin-Louis Cauchy (1789-1857) due to their relevance for the Cauchy problem of general relativity. Informal introduction Although it is usually phrased in terms of general relativity, the formal notion of a Cauchy surface can be understood in familiar terms. Suppose that humans can travel at a maximum speed of 20 miles per hour. This places constraints, for any given person, upon where they can reach by a certain time. For instance, it is impossible for a person who is in Mexico at 3 o'clock to arrive in Libya by 4 o'clock; however it is possible for a person who is in Manhattan at 1 o'clock to reach Brooklyn by 2 o'clock, since the locations are ten miles apart. So as to speak semi-formally, ignore time zones and travel difficulties, and suppose that travelers are immortal beings who have lived forever. The system of all possible ways to fill in the four blanks in defines the notion of a causal structure. A Cauchy surface for this causal structure is a collection of pairs of locations and times such that, for
https://en.wikipedia.org/wiki/Ice%20giant
An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur. There are two ice giants in the Solar System: Uranus and Neptune. In astrophysics and planetary science the term "ice" refers to volatile chemical compounds with freezing points above about 100 K, such as water, ammonia, or methane, with freezing points of 273 K (0°C), 195 K (−78°C), and 91 K (−182°C), respectively (see Volatiles). In the 1990s, it was determined that Uranus and Neptune were a distinct class of giant planet, separate from the other giant planets, Jupiter and Saturn, which are gas giants predominantly composed of hydrogen and helium. As such, Neptune and Uranus are now referred to as ice giants. Lacking well-defined solid surfaces, they are primarily composed of gases and liquids. Their constituent compounds were solids when they were primarily incorporated into the planets during their formation, either directly in the form of ice or trapped in water ice. Today, very little of the water in Uranus and Neptune remains in the form of ice. Instead, water primarily exists as supercritical fluid at the temperatures and pressures within them. Uranus and Neptune consist of only about 20% hydrogen and helium by mass, compared to the Solar System's gas giants, Jupiter and Saturn, which are more than 90% hydrogen and helium by mass. Terminology In 1952, science fiction writer James Blish coined the term gas giant and it was used
https://en.wikipedia.org/wiki/%C3%89tienne%20Bobillier
Étienne Bobillier (17 April 1798 – 22 March 1840) was a French mathematician. He was born in Lons-le-Saunier, France. At the age of 19 he was accepted into the École Polytechnique and studied there for a year. However, due to a shortage of money, in 1818 he became an instructor in mathematics at the École des Arts et Métiers in Châlons-sur-Marne. In 1829, he was sent to Angers to be director of studies. The following year he served in the national guard during the 1830 revolution. In 1832 he returned to Châlons after his post was abolished, and was promoted to professor. In 1836 he began suffering from health problems, but continued teaching; declining to take a leave to recuperate. As a result, he died in Châlons at the relatively early age of 41. He is noted for his work on geometry, particularly the algebraic treatment of geometric surfaces and the polars of curves. He also worked on statics and the catenary. The crater Bobillier on the Moon is named after him. Works Cours de géométrie, 1849 Principes d'algèbre, 1865 External links 1798 births 1840 deaths People from Lons-le-Saunier École Polytechnique alumni 19th-century French mathematicians
https://en.wikipedia.org/wiki/Biologist
A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in a particular branch (e.g., molecular biology, zoology, and evolutionary biology) of biology and have a specific research focus (e.g., studying malaria or cancer). Biologists who are involved in basic research have the aim of advancing knowledge about the natural world. They conduct their research using the scientific method, which is an empirical method for testing hypotheses. Their discoveries may have applications for some specific purpose such as in biotechnology, which has the goal of developing medically useful products for humans. In modern times, most biologists have one or more academic degrees such as a bachelor's degree plus an advanced degree like a master's degree or a doctorate. Like other scientists, biologists can be found working in different sectors of the economy such as in academia, nonprofits, private industry, or government. History Francesco Redi, the founder of biology, is recognized to be one of the greatest biologists of all time. Robert Hooke, an English natural philosopher, coined the term cell, suggesting plant structure's resemblance to honeycomb cells. Charles Darwin and Alfred Wallace independently formulated the theory of evolution by natural selection, which was described in detail in Darwin's book
https://en.wikipedia.org/wiki/Ideal%20chain
In polymer chemistry, an ideal chain (or freely-jointed chain) is the simplest model to describe polymers, such as nucleic acids and proteins. It assumes that the monomers in a polymer are located at the steps of a hypothetical random walker that does not remember its previous steps. By neglecting interactions among monomers, this model assumes that two (or more) monomers can occupy the same location. Although it is simple, its generality gives insight about the physics of polymers. In this model, monomers are rigid rods of a fixed length , and their orientation is completely independent of the orientations and positions of neighbouring monomers. In some cases, the monomer has a physical interpretation, such as an amino acid in a polypeptide. In other cases, a monomer is simply a segment of the polymer that can be modeled as behaving as a discrete, freely jointed unit. If so, is the Kuhn length. For example, chromatin is modeled as a polymer in which each monomer is a segment approximately 14-46 kbp in length. The model N mers form the polymer, whose total unfolded length is: where N is the number of mers. In this very simple approach where no interactions between mers are considered, the energy of the polymer is taken to be independent of its shape, which means that at thermodynamic equilibrium, all of its shape configurations are equally likely to occur as the polymer fluctuates in time, according to the Maxwell–Boltzmann distribution. Let us call the total end t
https://en.wikipedia.org/wiki/Oseledets%20theorem
In mathematics, the multiplicative ergodic theorem, or Oseledets theorem provides the theoretical background for computation of Lyapunov exponents of a nonlinear dynamical system. It was proved by Valery Oseledets (also spelled "Oseledec") in 1965 and reported at the International Mathematical Congress in Moscow in 1966. A conceptually different proof of the multiplicative ergodic theorem was found by M. S. Raghunathan. The theorem has been extended to semisimple Lie groups by V. A. Kaimanovich and further generalized in the works of David Ruelle, Grigory Margulis, Anders Karlsson, and François Ledrappier. Cocycles The multiplicative ergodic theorem is stated in terms of matrix cocycles of a dynamical system. The theorem states conditions for the existence of the defining limits and describes the Lyapunov exponents. It does not address the rate of convergence. A cocycle of an autonomous dynamical system X is a map C : X×T → Rn×n satisfying where X and T (with T = Z⁺ or T = R⁺) are the phase space and the time range, respectively, of the dynamical system, and In is the n-dimensional unit matrix. The dimension n of the matrices C is not related to the phase space X. Examples A prominent example of a cocycle is given by the matrix Jt in the theory of Lyapunov exponents. In this special case, the dimension n of the matrices is the same as the dimension of the manifold X. For any cocycle C, the determinant det C(x, t) is a one-dimensional cocycle. Statement of the the
https://en.wikipedia.org/wiki/225%20%28number%29
225 (two hundred [and] twenty-five) is the natural number following 224 and preceding 226. In mathematics 225 is the smallest number that is a polygonal number in five different ways. It is a square number , an octagonal number, and a squared triangular number . As the square of a double factorial, counts the number of permutations of six items in which all cycles have even length, or the number of permutations in which all cycles have odd length. And as one of the Stirling numbers of the first kind, it counts the number of permutations of six items with exactly three cycles. 225 is a highly composite odd number, meaning that it has more divisors than any smaller odd numbers. After 1 and 9, 225 is the third smallest number n for which , where σ is the sum of divisors function and φ is Euler's totient function. 225 is a refactorable number. 225 is the smallest square number to have one of every digit in some number base (225 is 3201 in base 4) 225 is the first odd number with exactly 9 divisors. References Integers
https://en.wikipedia.org/wiki/Antoine%20%C3%89mile%20Henry%20Labeyrie
Antoine Émile Henry Labeyrie (born 12 May 1943) is a French astronomer, who held the Observational astrophysics chair at the Collège de France between 1991 and 2014, where he is currently professor emeritus. He is working with the Hypertelescope Lise association, which aims to develop an extremely large astronomical interferometer with spherical geometry that might theoretically show features on Earth-like worlds around other suns, as its president. He is a member of the French Academy of Sciences in the Sciences of the Universe (sciences de l'univers) section. Between 1995 and 1999 he was director of the Haute-Provence Observatory. Labeyrie graduated from the "grande école" SupOptique (École supérieure d'optique). He invented speckle interferometry, and works with astronomical interferometers. Labeyrie concentrated particularly on the use of "diluted optics" beam combination or "densified pupils" of a similar type but larger scale than those Michelson used for measuring the diameters of stars in the 1920s, in contrast to other astronomical interferometer researchers who generally switched to pupil-plane beam combination in the 1980s and 1990s. The main-belt asteroid 8788 Labeyrie (1978 VP2) is named in honor of Antoine Émile Henry Labeyrie and Catherine Labeyrie. In 2000, he was awarded The Benjamin Franklin Medal. Hypertelescope Labeyrie has proposed the idea of an astronomical interferometer where the individual telescopes are positioned in a spherical arrangement (req
https://en.wikipedia.org/wiki/Timothy%20M.%20Chan
Timothy Moon-Yew Chan is a Founder Professor in the Department of Computer Science at the University of Illinois at Urbana–Champaign. He was formerly Professor and University Research Chair in the David R. Cheriton School of Computer Science, University of Waterloo, Canada. He graduated with BA (summa cum laude) from Rice University in 1992, and completed his Ph.D. in Computer Science at UBC in 1995 at the age of 19. His late mother, Miu Yung Chan, was a molecular physicist with a Ph.D. from Ohio State University. He is currently an associate editor for SIAM Journal on Computing and the International Journal of Computational Geometry and Applications. He is also a member of the editorial board of Algorithmica, Discrete & Computational Geometry, and Computational Geometry: Theory and Applications. Chan has published extensively. His research covers data structures, algorithms, and computational geometry. Recognition He was awarded the Governor General's Gold Medal (as Head of Graduating Class in the Faculty of Graduate Studies at the University of British Columbia during convocation), the NSERC doctoral prize, and the Premier's Research Excellence Award (PREA) of Ontario, Canada. He was elected as an ACM Fellow in 2019 "for contributions to computational geometry, algorithms, and data structures". See also Chan's algorithm, an output-sensitive algorithm for planar convex hulls References External links Chan's web site at University of Illinois at Urbana-Champaign Liv
https://en.wikipedia.org/wiki/Autolysis%20%28biology%29
In biology, autolysis, more commonly known as self-digestion, refers to the destruction of a cell through the action of its own enzymes. It may also refer to the digestion of an enzyme by another molecule of the same enzyme. The term derives from the Greek αὐτο- 'self' and λύσις 'splitting'. Biochemical mechanisms of cell destruction Autolysis is uncommon in living adult organisms and usually occurs in necrotic tissue as enzymes act on components of the cell that would not normally serve as substrates. These enzymes are released due to the cessation of active processes in the cell that provide substrates in healthy, living tissue; autolysis in itself is not an active process. In other words, though autolysis resembles the active process of digestion of nutrients by live cells, the dead cells are not actively digesting themselves as is often claimed, and as the synonym self-digestion suggests. Failure of respiration and subsequent failure of oxidative phosphorylation is the trigger of the autolytic process. The reduced availability and subsequent absence of high-energy molecules that are required to maintain the integrity of the cell and maintain homeostasis causes significant changes in the biochemical operation of the cell. Molecular oxygen serves as the terminal electron acceptor in the series of biochemical reactions known as oxidative phosphorylation that are ultimately responsible for the synthesis of adenosine triphosphate, the main source of energy for otherwise t
https://en.wikipedia.org/wiki/Environmental%20education
Environmental education (EE) refers to organized efforts to teach how natural environments function, and particularly, how human beings can manage behavior and ecosystems to live sustainably. It is a multi-disciplinary field integrating disciplines such as biology, chemistry, physics, ecology, earth science, atmospheric science, mathematics, and geography. The United Nations Educational, Scientific and Cultural Organization (UNESCO) states that EE is vital in imparting an inherent respect for nature among society and in enhancing public environmental awareness. UNESCO emphasises the role of EE in safeguarding future global developments of societal quality of life (QOL), through the protection of the environment, eradication of poverty, minimization of inequalities and insurance of sustainable development. The term often implies education within the school system, from primary to post-secondary. However, it sometimes includes all efforts to educate the public and other audiences, including print materials, websites, media campaigns, etc.. There are also ways that environmental education is taught outside the traditional classroom. Aquariums, zoos, parks, and nature centers all have ways of teaching the public about the environment. UNESCO and environmental awareness and education UNESCO's involvement in environmental awareness and education goes back to the very beginnings of the Organization, with the creation in 1948 of the IUCN (International Union for the Conservation
https://en.wikipedia.org/wiki/Orange%20%28software%29
Orange is an open-source data visualization, machine learning and data mining toolkit. It features a visual programming front-end for explorative qualitative data analysis and interactive data visualization. Description Orange is a component-based visual programming software package for data visualization, machine learning, data mining, and data analysis. Orange components are called widgets. They range from simple data visualization, subset selection, and preprocessing to empirical evaluation of learning algorithms and predictive modeling. Visual programming is implemented through an interface in which workflows are created by linking predefined or user-designed widgets, while advanced users can use Orange as a Python library for data manipulation and widget alteration. Software Orange is an open-source software package released under GPL and hosted on GitHub. Versions up to 3.0 include core components in C++ with wrappers in Python. From version 3.0 onwards, Orange uses common Python open-source libraries for scientific computing, such as numpy, scipy and scikit-learn, while its graphical user interface operates within the cross-platform Qt framework. The default installation includes a number of machine learning, preprocessing and data visualization algorithms in 6 widget sets (data, transform, visualize, model, evaluate and unsupervised). Additional functionalities are available as add-ons (text-mining, image analytics, bioinformatics, etc.). Orange is supported
https://en.wikipedia.org/wiki/Optical%20theorem
In physics, the optical theorem is a general law of wave scattering theory, which relates the zero-angle scattering amplitude to the total cross section of the scatterer. It is usually written in the form where (0) is the scattering amplitude with an angle of zero, that is the amplitude of the wave scattered to the center of a distant screen and is the wave vector in the incident direction. Because the optical theorem is derived using only conservation of energy, or in quantum mechanics from conservation of probability, the optical theorem is widely applicable and, in quantum mechanics, includes both elastic and inelastic scattering. The generalized optical theorem, first derived by Werner Heisenberg, follows from the unitary condition and is given by where is the scattering amplitude that depends on the direction of the incident wave and the direction of scattering and is the differential solid angle. When , the above relation yields the optical theorem since the left-hand side is just twice the imaginary part of and since . For scattering in a centrally symmetric field, depends only on the angle between and , in which case, the above relation reduces to where and are the angles between and and some direction . History The optical theorem was originally developed independently by Wolfgang Sellmeier and Lord Rayleigh in 1871. Lord Rayleigh recognized the zero-angle scattering amplitude in terms of the index of refraction as (where is the number density
https://en.wikipedia.org/wiki/Klotho%20%28biology%29
Klotho is an enzyme that in humans is encoded by the KL gene. The three subfamilies of klotho are α-klotho, β-klotho, and γ-klotho. α-klotho activates FGF23, and β-klotho activates FGF19 and FGF21. When the subfamily is not specified, the word "klotho" typically refers to the α-klotho subfamily, because α-klotho was discovered before the other members. α-klotho is highly expressed in the brain, liver and kidney. β-klotho is predominantly expressed in the liver. γ-klotho is expressed in the skin. Klotho can exist in a membrane-bound form or a (hormonal) soluble, circulating form. Proteases can convert the membrane-bound form into the circulating form. The KL gene encodes a type-I single-pass transmembrane protein that is related to β-glucuronidases. Reduced production of this protein has been observed in patients with chronic kidney failure (CKF), and this may be one of the factors underlying degenerative processes (e.g., arteriosclerosis, osteoporosis, and skin atrophy) seen in CKF. Mutations within the family have been associated with ageing, bone loss and alcohol consumption. Transgenic mice that overexpress Klotho live longer than wild-type mice. Structure The α-klotho gene is located on chromosome 13, and is translated into a single-pass integral membrane protein. The intracellular portion of the α-klotho protein is short (11 amino acids), whereas the extracellular portion is long (980 amino acids). The transmembrane portion is also comparatively short (21 amino acid
https://en.wikipedia.org/wiki/Fereydoon%20Family
Fereydoon Family (born September 18, 1945) is a leading Persian physicist in the field of nanotechnology and solid-state physics. He is currently Samuel Candler Dobbs Professor of Physics and a member of the Emerson Center for Scientific Computation at Emory University in Atlanta, Georgia. He is an elected fellow of the American Physical Society, and a recipient of the Southeastern Section of the American Physical Society's highest honor, the J.W. Beams Award. Biography Family received his B.S. degree in physics from Worcester Polytechnic Institute in 1968 and his Ph.D in physics at Clark University in 1974. He has been a visiting scientist at the Institute for Theoretical Physics at the University of California at Santa Barbara and a visiting associate professor of chemistry at Massachusetts Institute of Technology. Publications Journal articles He has published 161 scientific papers, almost all of them in high-ranking peer-reviewed journals. The most heavily cited was cited as many as 547 times. The ten most frequently cited are: Family F, Vicsek T, Scaling of the Active Zone in the Eden Process on Percolation Networks and the Ballistic Deposition Model Journal of Physics A-Mathematical and General 18 (2): L75-L81 1985' (times cited: 547) Vicsek T, Family F, Dynamic Scaling for Aggregation of Clusters Physical Review Letters 52 (19): 1669-1672 1984 (times cited: 289) Family F, Dynamic Scaling and Phase-Transitions in Interface Growth Physica A 168 (1): 561-580 Sep 1
https://en.wikipedia.org/wiki/Dog%20health
The health of dogs is a well studied area in veterinary medicine. Dog health is viewed holistically; it encompasses many different aspects, including disease processes, genetics, and nutritional health, for example. Infectious diseases that affect dogs are important not only from a veterinary standpoint, but also because of the risk to public health; an example of this is rabies. Genetic disorders also affect dogs, often due to selective breeding to produce individual dog breeds. Due to the popularity of both commercial and homemade dog foods, nutrition is also a heavily studied subject. Diseases Some diseases and other health problems are common to both humans and dogs; others are unique to dogs and other animals. Dogs are susceptible to various diseases; similarly to humans, they can have diabetes, epilepsy, cancer, or arthritis. Timely vaccination can reduce the risk and severity of an infection. The most commonly recommended viruses to vaccinate dogs against are: Rabies CDV (canine distemper) CAV-2 (canine hepatitis virus or adenovirus-2) Canine herpesvirus Canine influenza CPV-2 (canine parvovirus) Kennel cough Leptospirosis Lyme disease Infectious diseases An infectious disease is caused by the presence of organisms such as viruses, bacteria, fungi, or parasites (either animalian or protozoan). Most of these diseases are spread directly from dog to dog, while others require a vector such as a tick or mosquito. Certain infectious diseases are a concern f
https://en.wikipedia.org/wiki/Alpha%20Magnetic%20Spectrometer
The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment module that is mounted on the International Space Station (ISS). The experiment is a recognized CERN experiment (RE1). The module is a detector that measures antimatter in cosmic rays; this information is needed to understand the formation of the Universe and search for evidence of dark matter. The principal investigator is Nobel laureate particle physicist Samuel Ting. The launch of flight STS-134 carrying AMS-02 took place on May 16, 2011, and the spectrometer was installed on May 19, 2011. By April 15, 2015, AMS-02 had recorded over 60 billion cosmic ray events and 90 billion after five years of operation since its installation in May 2011. In March 2013, Professor Ting reported initial results, saying that AMS had observed over 400,000 positrons, with the positron to electron fraction increasing from 10 GeV to 250 GeV. (Later results have shown a decrease in positron fraction at energies over about 275 GeV). There was "no significant variation over time, or any preferred incoming direction. These results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations." The results have been published in Physical Review Letters. Additional data are still being collected. History The alpha magnetic spectrometer was proposed in 1995 by the Antimatter Study Group, led by MIT particle physicist
https://en.wikipedia.org/wiki/S.T.%20Hindu%20College
South Travancore Hindu College, is a general degree college located in Nagercoil, Kanyakumari district, Tamil Nadu. It was established in the year 1952. The college is affiliated with Manonmaniam Sundaranar University. This college offers different courses in arts, commerce and science. Departments Science Physics Chemistry Mathematics Botany Zoology Computer Application Electronics Arts and Commerce Tamil Malayalam English Sociology Economics History and tourism Commerce Business Administration Accreditation The college is recognized by the University Grants Commission (UGC). References Educational institutions established in 1952 1952 establishments in Madras State Colleges affiliated to Manonmaniam Sundaranar University Universities and colleges in Kanyakumari district Academic institutions formerly affiliated with the University of Madras Hindu universities and colleges
https://en.wikipedia.org/wiki/Equidistribution%20theorem
In mathematics, the equidistribution theorem is the statement that the sequence a, 2a, 3a, ... mod 1 is uniformly distributed on the circle , when a is an irrational number. It is a special case of the ergodic theorem where one takes the normalized angle measure . History While this theorem was proved in 1909 and 1910 separately by Hermann Weyl, Wacław Sierpiński and Piers Bohl, variants of this theorem continue to be studied to this day. In 1916, Weyl proved that the sequence a, 22a, 32a, ... mod 1 is uniformly distributed on the unit interval. In 1937, Ivan Vinogradov proved that the sequence pn a mod 1 is uniformly distributed, where pn is the nth prime. Vinogradov's proof was a byproduct of the odd Goldbach conjecture, that every sufficiently large odd number is the sum of three primes. George Birkhoff, in 1931, and Aleksandr Khinchin, in 1933, proved that the generalization x + na, for almost all x, is equidistributed on any Lebesgue measurable subset of the unit interval. The corresponding generalizations for the Weyl and Vinogradov results were proven by Jean Bourgain in 1988. Specifically, Khinchin showed that the identity holds for almost all x and any Lebesgue integrable function ƒ. In modern formulations, it is asked under what conditions the identity might hold, given some general sequence bk. One noteworthy result is that the sequence 2ka mod 1 is uniformly distributed for almost all, but not all, irrational a. Similarly, for the sequence bk = 2ka
https://en.wikipedia.org/wiki/Johann%20Gottlieb%20Friedrich%20von%20Bohnenberger
Johann Gottlieb Friedrich von Bohnenberger (5 June 1765 – 19 April 1831) was a German astronomer born at Simmozheim, Württemberg. He studied at the University of Tübingen. In 1798, he was appointed professor of mathematics and astronomy at the University. He published: Anleitung zur geographischen Ortsbestimmung (Guide to geographic locations), 1795 Astronomie (Astronomy), 1811 Anfangsgründe der höhern Analysis (Initial reasons of higher analysis), 1812. In 1817, he systematically explained the design and use of a gyroscope apparatus which he called simply a “Machine.” Several examples of the 'Machine' were constructed by Johann Wilhelm Gottlob Buzengeiger of Tübingen. Johann Friedrich Benzenberg had already mentioned Bohnenberger's invention (describing it at length) in several letters beginning in 1810. Bohnenberger died at Tübingen. The lunar crater Bohnenberger is named after him. See also Bohnenberger electrometer Kater's pendulum References External links Bohnenberger's apparatus (gyroscope) 18th-century German mathematicians 19th-century German mathematicians 18th-century German astronomers 19th-century German inventors 1765 births 1831 deaths 19th-century German astronomers Members of the Göttingen Academy of Sciences and Humanities People from the Kingdom of Württemberg Mathematicians from the Holy Roman Empire
https://en.wikipedia.org/wiki/Host%20signal%20processing
Host signal processing (HSP) is a term used in computing to describe hardware such as a modem or printer which is emulated (to various degrees) in software. Intel refers to the technology as native signal processing (NSP). HSP replaces dedicated DSP or ASIC hardware by using the general purpose CPU of the host computer. Modems using HSP are known as winmodems (a term trademarked by 3COM / USRobotics, but genericized) or softmodems. Printers using HSP are known as GDI printers (after the MS Windows GDI software interface), winprinters (named after winmodems) or softprinters. The Apple II Disk II floppy drive used the host CPU to process drive control signals, instead of a microcontroller. This instance of HSP predates the usage of the terms HSP and NSP. In the mid- to late-1990s, Intel pursued native signal processing technology to improve multimedia handling. According to testimony by Intel, Microsoft opposed development of NSP because the technology could reduce the necessity of the Microsoft Windows operating system. Intel claims to have terminated development of NSP because of threats from Microsoft. References Computing terminology Digital signal processing
https://en.wikipedia.org/wiki/John%20E.%20Baldwin
John Evan Baldwin FRS (6 December 1931 – 7 December 2010) was a British astronomer who worked at the Cavendish Astrophysics Group (formerly Mullard Radio Astronomy Observatory) from 1954. He played a role in the development of interferometry in Radio Astronomy, and later astronomical optical interferometry and lucky imaging. He made the first maps of the radio emission from the Andromeda Galaxy and the Perseus Cluster, and measured the properties of many active galaxies. In 1985 he performed the first Aperture Masking Interferometry observations, and then led the construction and operation of the Cambridge Optical Aperture Synthesis Telescope, and helped develop the lucky imaging method. In 2001 he was awarded the Jackson-Gwilt Medal for his technical contributions to the fields of interferometry and aperture synthesis. He matriculated as a member of Queens' College, Cambridge in 1949 and was a Life Fellow of the College from 1999 to his death in 2010. References External links - John Baldwin's page at the MRAO - Photo of John Baldwin with Jan Hendrik Oort, Bob Rubin and Vera Rubin 1931 births 2010 deaths 20th-century British astronomers Alumni of Queens' College, Cambridge Fellows of Queens' College, Cambridge Fellows of the Royal Society
https://en.wikipedia.org/wiki/Coherent%20control
Coherent control is a quantum mechanics-based method for controlling dynamic processes by light. The basic principle is to control quantum interference phenomena, typically by shaping the phase of laser pulses. The basic ideas have proliferated, finding vast application in spectroscopy mass spectra, quantum information processing, laser cooling, ultracold physics and more. Brief History The initial idea was to control the outcome of chemical reactions. Two approaches were pursued: in the time domain, a "pump-dump" scheme where the control is the time delay between pulses in the frequency domain, interfering pathways controlled by one and three photons. The two basic methods eventually merged with the introduction of optimal control theory. Experimental realizations soon followed in the time domain and in the frequency domain. Two interlinked developments accelerated the field of coherent control: experimentally, it was the development of pulse shaping by a spatial light modulator and its employment in coherent control. The second development was the idea of automatic feedback control and its experimental realization. Controllability Coherent control aims to steer a quantum system from an initial state to a target state via an external field. For given initial and final (target) states, the coherent control is termed state-to-state control. A generalization is steering simultaneously an arbitrary set of initial pure states to an arbitrary set of final states i.e. con
https://en.wikipedia.org/wiki/Robinson%20arithmetic
In mathematics, Robinson arithmetic is a finitely axiomatized fragment of first-order Peano arithmetic (PA), first set out by Raphael M. Robinson in 1950. It is usually denoted Q. Q is almost PA without the axiom schema of mathematical induction. Q is weaker than PA but it has the same language, and both theories are incomplete. Q is important and interesting because it is a finitely axiomatized fragment of PA that is recursively incompletable and essentially undecidable. Axioms The background logic of Q is first-order logic with identity, denoted by infix '='. The individuals, called natural numbers, are members of a set called N with a distinguished member 0, called zero. There are three operations over N: A unary operation called successor and denoted by prefix S; Two binary operations, addition and multiplication, denoted by infix + and ·, respectively. The following axioms for Q are Q1–Q7 in (cf. also the axioms of first-order arithmetic). Variables not bound by an existential quantifier are bound by an implicit universal quantifier. Sx ≠ 0 0 is not the successor of any number. (Sx = Sy) → x = y If the successor of x is identical to the successor of y, then x and y are identical. (1) and (2) yield the minimum of facts about N (it is an infinite set bounded by 0) and S (it is an injective function whose domain is N) needed for non-triviality. The converse of (2) follows from the properties of identity. y=0 ∨ ∃x (Sx = y) Every number is either 0 or the successo
https://en.wikipedia.org/wiki/Doug%20Logan
Douglas George Logan y Gonzales de Mendoza (born 1943) is an American sports executive. He was the inaugural commissioner of Major League Soccer, and later served as the CEO of USA Track & Field. Early life Logan was born in New Jersey to an American father and Cuban mother. He was studying civil engineering at Manhattan College when he was drafted into the military in 1964. He served with the 101st Airborne Division in Vietnam and was decorated with two Bronze Stars. He later studied at the University of Baltimore Law School, graduating in 1972. Career Early career From 1986 to 1993, Logan was a senior vice president of Ogden Entertainment Services. He later became president and chief executive officer of Mexican entertainment company OCESA. Under his management, the Mexico Aztecas of the Continental Basketball Association became the first American professional sports franchise based in Mexico. The Aztecas relocated to San Diego and became the Wildcards for the 1996 season before folding. MLS Commissioner In 1995, Logan was named the first commissioner of Major League Soccer, serving in that capacity through 1999. Sports Business Daily named Logan and the MLS staff Sports Industrialists of the Year for 1996. During Logan's last year at MLS, the league lost $34 million. MLS was reported to have lost $250 million in its first five years under Logan. Later career In 1999, Logan formed the sports consulting firm Empresario. In 2001, he was hired as a consultant in the cre
https://en.wikipedia.org/wiki/Systolic%20geometry
In mathematics, systolic geometry is the study of systolic invariants of manifolds and polyhedra, as initially conceived by Charles Loewner and developed by Mikhail Gromov, Michael Freedman, Peter Sarnak, Mikhail Katz, Larry Guth, and others, in its arithmetical, ergodic, and topological manifestations. See also a slower-paced Introduction to systolic geometry. The notion of systole The systole of a compact metric space X is a metric invariant of X, defined to be the least length of a noncontractible loop in X (i.e. a loop that cannot be contracted to a point in the ambient space X). In more technical language, we minimize length over free loops representing nontrivial conjugacy classes in the fundamental group of X. When X is a graph, the invariant is usually referred to as the girth, ever since the 1947 article on girth by W. T. Tutte. Possibly inspired by Tutte's article, Loewner started thinking about systolic questions on surfaces in the late 1940s, resulting in a 1950 thesis by his student Pao Ming Pu. The actual term "systole" itself was not coined until a quarter century later, by Marcel Berger. This line of research was, apparently, given further impetus by a remark of René Thom, in a conversation with Berger in the library of Strasbourg University during the 1961–62 academic year, shortly after the publication of the papers of R. Accola and C. Blatter. Referring to these systolic inequalities, Thom reportedly exclaimed: Mais c'est fondamental! [These results ar
https://en.wikipedia.org/wiki/English%20in%20computing
The English language is sometimes described as the lingua franca of computing. In comparison to other sciences, where Latin and Greek are often the principal sources of vocabulary, computer science borrows more extensively from English. In the past, due to the technical limitations of early computers, and the lack of international standardization on the Internet, computer users were limited to using English and the Latin alphabet. However, this historical limitation is less present today, due to innovations in internet infrastructure and increases in computer speed. Most software products are localized in numerous languages and the invention of the Unicode character encoding has resolved problems with non-Latin alphabets. Some limitations have only been changed recently, such as with domain names, which previously allowed only ASCII characters. English is seen as having this role due to the prominence of the United States and the United Kingdom, both English-speaking countries, in the development and popularization of computer systems, computer networks, software and information technology. History Computer Science has an ultimately mathematical foundation which was laid by non-English speaking cultures. The first mathematically literate societies in the Ancient Near East recorded methods for solving mathematical problems in steps, The word 'algorithm' comes from the name of a famous medieval Arabic mathematician who contributed to the spread of Hindu-Arabic numerals, al-Kh
https://en.wikipedia.org/wiki/Enstrophy
In fluid dynamics, the enstrophy can be interpreted as another type of potential density; or, more concretely, the quantity directly related to the kinetic energy in the flow model that corresponds to dissipation effects in the fluid. It is particularly useful in the study of turbulent flows, and is often identified in the study of thrusters as well as in combustion theory and meteorology. Given a domain and a once-weakly differentiable vector field which represents a fluid flow, such as a solution to the Navier-Stokes equations, its enstrophy is given by:where . This quantity is the same as the squared seminorm of the solution in the Sobolev space . Incompressible flow In the case that the flow is incompressible, or equivalently that , the enstrophy can be described as the integral of the square of the vorticity : or, in terms of the flow velocity: In the context of the incompressible Navier-Stokes equations, enstrophy appears in the following useful result: The quantity in parentheses on the left is the kinetic energy in the flow, so the result says that energy declines proportional to the kinematic viscosity times the enstrophy. See also Atmospheric circulation Turbulence References Further reading Continuum mechanics Fluid dynamics Turbulence
https://en.wikipedia.org/wiki/Jon%20E.%20Ahlquist
Jon Edward Ahlquist (27 July 1944 –7 May 2020) was an American molecular biologist and ornithologist who has specialized in molecular phylogenetics. He has collaborated extensively with Charles Sibley, primarily at Yale University. By 1987, both Ahlquist and Sibley had left Yale. In 1988, Ahlquist and Sibley were awarded the Daniel Giraud Elliot Medal by the National Academy of Sciences. In January 1991 (often listed as 1990), Charles Sibley and Ahlquist published Phylogeny and Classification of Birds, which presented a new phylogeny for birds based on DNA-DNA hybridisation techniques, known as the Sibley-Ahlquist taxonomy. At that time, he was an associate professor of zoology at Ohio University. In 1999, Ahlquist was retired. See also Sibley–Ahlquist taxonomy References American ornithologists Living people Ohio University faculty 1944 births
https://en.wikipedia.org/wiki/David%20Sahadi
David Sahadi (born October 24, 1961, in Brooklyn, New York) is an American multimedia producer, currently working for the professional wrestling promotion Impact Wrestling. He is also known for his time with the World Wrestling Federation. Biography Sahadi attended college and earned a degree in mathematics, but had grown disenchanted with mathematics by the time he graduated. He spent the summer following his graduation painting houses before his father obtained him a Sunday job working for NBC Sports as a "logger", a job which required him to watch football games broadcast on NBC and take a detailed record of the events of the game in order to help with the production of highlight reels. After the football season ended, Sahadi began working in the sports promotions department as a production assistant. Two years later, he was made Highlight Supervisor, producing packages which would be sent to Bob Costas, who would add a voiceover. Sahadi was eventually promoted to the position of Manager of On-Air Promotions for NBC Sports, and produced advertising campaigns for the NFL, NBA and the 1992 Summer Olympics. It was then that Sahadi began to come into conflict with his employees, as, while he wanted to create fast-paced video packages, NBC favored a more sedate editing style. When he was approached by the World Wrestling Federation (a national professional wrestling promotion) before the 1992 Olympics, Sahadi accepted their job offer. World Wrestling Federation / Entertainme
https://en.wikipedia.org/wiki/Miguel%20A.%20Catal%C3%A1n
Miguel Antonio Catalán y Sañudo (1894–1957) was a Spanish spectroscopist. Biography Miguel Antonio Catalán y Sañudo was born in Zaragoza, he obtained his degree in chemistry from the University of Zaragoza and received his doctorate in Madrid in 1917 for his thesis about spectrochemistry. In 1920, he began work as a researcher at Imperial College London. Examining the spectrum of the arc of manganese, he determined that the optical spectra of complex atoms consisted of groups of lines –which he called "multipletes"- between which existed certain characteristic regularities. Catalán demonstrated that study of the multipletes led to further understanding of the states of energy of atomic electrons. On the invitation of Arnold Sommerfeld, he worked at the University of Munich, and on the creation by the Rockefeller Foundation of the Institute of Physics and Chemistry (Madrid), in 1930 he was named head of the Spectroscopy Section. He was invited numerous times to work in the laboratories of the National Bureau of Standards (Washington, D.C.), Princeton University, and MIT. He published more than 70 scientific articles in specialized journals. In 1926, he received a prize from the Real Academia de Ciencias (Spain) and in 1930, the international Pelfort prize. He married Jimena Menéndez-Pidal, the daughter of Royal Spanish Academy director Ramón Menéndez Pidal and María Goyri. Because of the military coup by General Francisco Franco in July 1936, he and his father in law were
https://en.wikipedia.org/wiki/Light%20intensity
Several measures of light are commonly known as intensity: Radiant intensity, a radiometric quantity measured in watts per steradian (W/sr) Luminous intensity, a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd) Irradiance, a radiometric quantity, measured in watts per square meter (W/m2) Intensity (physics), the name for irradiance used in other branches of physics (W/m2) Radiance, commonly called "intensity" in astronomy and astrophysics (W·sr−1·m−2) See also Brightness, the subjective perception elicited by the luminance of a source Luminance, the photometric equivalent of radiance (lm·sr−1·m−2) Photometry (optics), measurement of light, in terms of its perceived brightness to the human eye Radiometry, measurement of light, in absolute power units Luminosity
https://en.wikipedia.org/wiki/Provable%20prime
In number theory, a provable prime is an integer that has been calculated to be prime using a primality-proving algorithm. Boot-strapping techniques using Pocklington primality test are the most common ways to generate provable primes for cryptography. Contrast with probable prime, which is likely (but not certain) to be prime, based on the output of a probabilistic primality test. In principle, every prime number can be proved to be prime in polynomial time by using the AKS primality test. Other methods which guarantee that their result is prime, but which do not work for all primes, are useful for the random generation of provable primes. Provable primes have also been generated on embedded devices. See also Probable prime Primality test References Primality tests Prime numbers
https://en.wikipedia.org/wiki/Finite%20character
In mathematics, a family of sets is of finite character if for each , belongs to if and only if every finite subset of belongs to . That is, For each , every finite subset of belongs to . If every finite subset of a given set belongs to , then belongs to . Properties A family of sets of finite character enjoys the following properties: For each , every (finite or infinite) subset of belongs to . Every nonempty family of finite character has a maximal element with respect to inclusion (Tukey's lemma): In , partially ordered by inclusion, the union of every chain of elements of also belongs to , therefore, by Zorn's lemma, contains at least one maximal element. Example Let be a vector space, and let be the family of linearly independent subsets of . Then is a family of finite character (because a subset is linearly dependent if and only if has a finite subset which is linearly dependent). Therefore, in every vector space, there exists a maximal family of linearly independent elements. As a maximal family is a vector basis, every vector space has a (possibly infinite) vector basis. See also Hereditarily finite set References Families of sets
https://en.wikipedia.org/wiki/Reaction%20norm
In ecology and genetics, a reaction norm, also called a norm of reaction, describes the pattern of phenotypic expression of a single genotype across a range of environments. One use of reaction norms is in describing how different species—especially related species—respond to varying environments. But differing genotypes within a single species may also show differing reaction norms relative to a particular phenotypic trait and environment variable. For every genotype, phenotypic trait, and environmental variable, a different reaction norm can exist; in other words, an enormous complexity can exist in the interrelationships between genetic and environmental factors in determining traits. The concept was introduced by Richard Woltereck in 1909. A monoclonal example Scientifically analyzing norms of reaction in natural populations can be very difficult, simply because natural populations of sexually reproductive organisms usually do not have cleanly separated or superficially identifiable genetic distinctions. However, seed crops produced by humans are often engineered to contain specific genes, and in some cases seed stocks consist of clones. Accordingly, distinct seed lines present ideal examples of differentiated norms of reaction. In fact, agricultural companies market seeds for use in particular environments based on exactly this. Suppose the seed line A contains an allele a, and a seed line B of the same crop species contains an allele b, for the same gene. Wit
https://en.wikipedia.org/wiki/Abdal%20%28disambiguation%29
Abdal is a rank of forty Sufi saints in Islamic metaphysics and mysticism. Abdal may also refer to: Places Abdal, Azerbaijan, a village in the Agdam District of Azerbaijan Abdal, Punjab, a village in Amritsar Dist. of Indian state of Punjab Abdal, Gurdaspur, Punjab, a village in Gurdaspur Dist. of Indian state of Punjab Abdal, Iran, a village in Zanjan Province, Iran Abdal, Nebraska, a ghost town in the United States Other uses Abdal (caste), a Muslim community found in North India Abdals (ethnic group in West Asia), an ethnic group in Turkey, Syria, and the Balkans Qara Shemsi Abdal (1828–1886), a 19th-century Ottoman poet Äynu people of Xinjiang region, China Äynu language, the language of the Äynu Hephthalites were sometimes referred to as Abdals See also Dervish, a Sufi ascetic Abdul, component of many names from Arabic Abdali (disambiguation)
https://en.wikipedia.org/wiki/Michael%20Martin%20Hammer
Michael Martin Hammer (April 13, 1948 – Sept 3, 2008) was a Jewish-American engineer, management author, and a former professor of computer science at the Massachusetts Institute of Technology (MIT), known as one of the founders of the management theory of Business process reengineering (BPR). Biography Early life and education Hammer, the child of Holocaust survivors, grew up in Annapolis, Maryland. He earned BS, MS, and Ph.D. degrees in EECS from the Massachusetts Institute of Technology in 1968, 1970, and 1973 respectively. Career An engineer by training, Hammer was the proponent of a process-oriented view of business management. He was a professor at the Massachusetts Institute of Technology in the department of Computer Science and a lecturer in the MIT Sloan School of Management. Articles written by Hammer have been published in business periodicals, such as the Harvard Business Review and The Economist. TIME named him as one of America's 25 most influential individuals, in its first such list. Forbes magazine ranked Hammer's book, Reengineering the Corporation, among the "three most important business books of the past 20 years". Personal life He and his wife, Phyllis Thurm Hammer, lived in Newton, Massachusetts with their four children, Jessica, Allison, Dana, and David. Death Hammer died suddenly from complications of a brain hemorrhage he suffered while on vacation, and he is buried in the Baker Street Jewish Cemeteries in Boston. Publications Reengineering
https://en.wikipedia.org/wiki/End
End, END, Ending, or ENDS may refer to: End Mathematics End (category theory) End (topology) End (graph theory) End (group theory) (a subcase of the previous) End (endomorphism) Sports and games End (gridiron football) End, a division of play in the sports of curling, target archery and pétanque End (dominoes), one of the halves of the face of a domino tile Entertainment End (band) an American hardcore punk supergroup formed in 2017 End key on a modern computer keyboard End Records, a record label "End", a song by The Cure from Wish "Ends" (song) a 1998 song by Everlast, off the album Whitey Ford Sings the Blues End (album), by Explosions in the Sky Other uses End, in weaving, a single thread of the warp Ends (short story collection) (1988 book) anthology of Gordon R. Dickson stories END European Nuclear Disarmament Endoglin, a glycoprotein Equivalent narcotic depth, a concept used in underwater diving Environmental noise directive Ending Ending (linguistics), a linguistic morpheme Alternate ending End of a part of a baseball game Chess endgame Ending credits Post-credits scene False ending Happy ending Multiple endings Twist ending Endings (film), a 2012 film The Ending (Song), a 2012 song by Ellie Goulding off the album Halcyon This Ending (band) Swedish extreme metal band A repeat sign, in music theory "Endings", a Series E episode of the television series QI (2007) ENDS ENDS, electronic nicotine delivery system See also The End (disambiguation)
https://en.wikipedia.org/wiki/Rare%20Symmetry%20Violating%20Processes
The Rare Symmetry Violating Processes (RSVP) was a physics project terminated by the National Science Foundation, in August, 2005, originally meant for construction in the same year, at Brookhaven National Laboratory on Long Island. The Experiments The project's two experiments were to investigate the relation between the electron and its heavier cousin the muon, and to examine differences in the behavior of matter and antimatter, which were to utilize the existing Brookhaven particle accelerator called the Alternating Gradient Synchrotron (AGS). The project had been budgeted at approximately $145 million for construction, between fiscal year 2005 and 2010. Particle experiments
https://en.wikipedia.org/wiki/Event%20%28particle%20physics%29
In particle physics, an event refers to the results just after a fundamental interaction takes place between subatomic particles, occurring in a very short time span, at a well-localized region of space. Because of the uncertainty principle, an event in particle physics does not have quite the same meaning as it does in the theory of relativity, in which an "event" is a point in spacetime which can be known exactly, i.e., a spacetime coordinate. Overview In a typical particle physics event, the incoming particles are scattered or destroyed, and up to hundreds of particles can be produced, although few are likely to be new particles not discovered before. In the old bubble chambers and cloud chambers, "events" could be seen by observing charged particle tracks emerging from the region of the event before they curl due to the magnetic field through the chamber acting on the particles. At modern particle accelerators, events are the result of the interactions which occur from a beam crossing inside a particle detector. Physical quantities used to analyze events include the differential cross section, the flux of the beams (which in turn depends on the number density of the particles in the beam and their average velocity), and the rate and luminosity of the experiment. Individual particle physics events are modeled by scattering theory based on an underlying quantum field theory of the particles and their interactions. The S-matrix is used to characterize the probability of
https://en.wikipedia.org/wiki/Lund%20string%20model
In particle physics, the Lund string model is a phenomenological model of hadronization. It treats all but the highest-energy gluons as field lines, which are attracted to each other due to the gluon self-interaction and so form a narrow tube (or string) of strong color field. Compared to electric or magnetic field lines, which are spread out because the carrier of the electromagnetic force, the photon, does not interact with itself. String fragmentation is one of the parton fragmentation models used in the PYTHIA/Jetset and UCLA event generators, and explains many features of hadronization quite well. In particular, the model predicts that in addition to the particle jets formed along the original paths of two separating quarks, there will be a spray of hadrons produced between the jets by the string itself—which is precisely what is observed. This use of "string" is not the same as in string theory, in which strings are the fundamental objects of nature rather than collections of field lines. See also QCD string References Quantum chromodynamics Experimental particle physics
https://en.wikipedia.org/wiki/Erwin%20Kreyszig
Erwin Otto Kreyszig (January 6, 1922 in Pirna, Germany – December 12, 2008) was a German Canadian applied mathematician and the Professor of Mathematics at Carleton University in Ottawa, Ontario, Canada. He was a pioneer in the field of applied mathematics: non-wave replicating linear systems. He was also a distinguished author, having written the textbook Advanced Engineering Mathematics, the leading textbook for civil, mechanical, electrical, and chemical engineering undergraduate engineering mathematics. Kreyszig received his PhD degree in 1949 at the University of Darmstadt under the supervision of Alwin Walther. He then continued his research activities at the universities of Tübingen and Münster. Prior to joining Carleton University in 1984, he held positions at Stanford University (1954/55), the University of Ottawa (1955/56), Ohio State University (1956–60, professor 1957) and he completed his habilitation at the University of Mainz. In 1960 he became professor at the Technical University of Graz and organized the Graz 1964 Mathematical Congress. He worked at the University of Düsseldorf (1967–71) and at the University of Karlsruhe (1971–73). From 1973 through 1984 he worked at the University of Windsor and since 1984 he had been at Carleton University. He was awarded the title of Distinguished Research Professor in 1991 in recognition of a research career during which he published 176 papers in refereed journals, and 37 in refereed conference proceedings. Kreyszig
https://en.wikipedia.org/wiki/G-loading
G-loading may refer to: The act of applying g-force to an object in physics. General intelligence factor
https://en.wikipedia.org/wiki/Overhead%20%28computing%29
In computer science, overhead is any combination of excess or indirect computation time, memory, bandwidth, or other resources that are required to perform a specific task. It is a special case of engineering overhead. Overhead can be a deciding factor in software design, with regard to structure, error correction, and feature inclusion. Examples of computing overhead may be found in Object Oriented Programming (OOP), functional programming, data transfer, and data structures. Software design Choice of implementation A programmer/software engineer may have a choice of several algorithms, encodings, data types or data structures, each of which have known characteristics. When choosing among them, their respective overhead should also be considered. Tradeoffs In software engineering, overhead can influence the decision whether or not to include features in new products, or indeed whether to fix bugs. A feature that has a high overhead may not be included – or needs a big financial incentive to do so. Often, even though software providers are well aware of bugs in their products, the payoff of fixing them is not worth the reward, because of the overhead. For example, an implicit data structure or succinct data structure may provide low space overhead, but at the cost of slow performance (space/time tradeoff). Run-time complexity of software Algorithmic complexity is generally specified using Big O notation. This makes no comment on how long something takes to run or how muc
https://en.wikipedia.org/wiki/Overhead%20%28engineering%29
In engineering, some methods or components make special demands on the system. The extra design features necessary to meet these demands are called overhead. For instance, in electrical engineering, a particular integrated circuit might draw large current, requiring a robust power delivery circuit and a heat-dissipation mechanism. Example An example from software engineering is the encoding of information and data. The date and time "2011-07-12 07:18:47" can be expressed as Unix time with the 32-bit signed integer 1310447927, consuming only 4 bytes. Represented as ISO 8601 formatted UTF-8 encoded string 2011-07-12 07:18:47 the date would consume 19 bytes, a size overhead of 375% over the binary integer representation. As XML this date can be written as follows with an overhead of 218 characters, while adding the semantic context that it is a CHANGEDATE with index 1. <?xml version="1.0" encoding="UTF-8"?> <DATETIME qualifier="CHANGEDATE" index="1"> <YEAR>2011</YEAR> <MONTH>07</MONTH> <DAY>12</DAY> <HOUR>07</HOUR> <MINUTE>18</MINUTE> <SECOND>47</SECOND> </DATETIME> The 349 bytes resulting from the UTF-8 encoded XML correspond to a size overhead of 8725% over the original integer representation. See also Overhead (business) Engineering concepts
https://en.wikipedia.org/wiki/Perylene
Perylene or perilene is a polycyclic aromatic hydrocarbon with the chemical formula C20H12, occurring as a brown solid. It or its derivatives may be carcinogenic, and it is considered to be a hazardous pollutant. In cell membrane cytochemistry, perylene is used as a fluorescent lipid probe. It is the parent compound of a class of rylene dyes. Reactions Like other polycyclic aromatic compounds, perylene is reduced by alkali metals to give a deeply colored radical anion and a dianion. The diglyme solvates of these salts have been characterized by X-ray crystallography. Emission Perylene displays blue fluorescence. It is used as a blue-emitting dopant material in OLEDs, either pure or substituted. Perylene can be also used as an organic photoconductor. It has an absorption maximum at 434 nm, and as with all polycyclic aromatic compounds, low water solubility (1.2 x 10−5 mmol/L). Perylene has a molar absorptivity of 38,500 M−1cm−1 at 435.7 nm. Structure The perylene molecule consists of two naphthalene molecules connected by a carbon-carbon bond at the 1 and 8 positions on both molecules. All of the carbon atoms in perylene are sp2 hybridized. The structure of perylene has been extensively studied by X-ray crystallography. Biology Naturally occurring perylene quinones have been identified in lichens Laurera sanguinaria Malme and Graphis haematites Fée. References IARC Group 3 carcinogens Membrane biology Polycyclic aromatic hydrocarbons Organic semiconductors Fluorescen
https://en.wikipedia.org/wiki/Crypto%20API%20%28Linux%29
Crypto API is a cryptography framework in the Linux kernel, for various parts of the kernel that deal with cryptography, such as IPsec and dm-crypt. It was introduced in kernel version 2.5.45 and has since expanded to include essentially all popular block ciphers and hash functions. Userspace interfaces Many platforms that provide hardware acceleration of AES encryption expose this to programs through an extension of the instruction set architecture (ISA) of the various chipsets (e.g. AES instruction set for x86). With this sort of implementation any program (kernel-mode or user-space) may utilize these features directly. Some platforms, such as the ARM Kirkwood SheevaPlug and AMD Geode processors, however, are not implemented as ISA extensions, and are only accessible through kernel-mode drivers. In order for user-mode applications that utilize encryption, such as wolfSSL, OpenSSL or GnuTLS, to take advantage of such acceleration, they must interface with the kernel. AF_ALG A netlink-based interface that adds an AF_ALG address family; it was merged into version 2.6.38 of the Linux kernel mainline. There was once a plugin to OpenSSL to support AF_ALG, which has been submitted for merging. In version 1.1.0, OpenSSL landed another patch for AF_ALG contributed by Intel. wolfSSL can make use of AF_ALG and cryptodev The OpenBSD Cryptographic Framework /dev/crypto interface of OpenBSD was ported to Linux, but never merged. See also Microsoft CryptoAPI References A
https://en.wikipedia.org/wiki/Paul%20Bernays
Paul Isaac Bernays (17 October 1888 – 18 September 1977) was a Swiss mathematician who made significant contributions to mathematical logic, axiomatic set theory, and the philosophy of mathematics. He was an assistant and close collaborator of David Hilbert. Biography Bernays was born into a distinguished German-Jewish family of scholars and businessmen. His great-grandfather, Isaac ben Jacob Bernays, served as chief rabbi of Hamburg from 1821 to 1849. Bernays spent his childhood in Berlin, and attended the Köllner Gymnasium, 1895–1907. At the University of Berlin, he studied mathematics under Issai Schur, Edmund Landau, Ferdinand Georg Frobenius, and Friedrich Schottky; philosophy under Alois Riehl, Carl Stumpf and Ernst Cassirer; and physics under Max Planck. At the University of Göttingen, he studied mathematics under David Hilbert, Edmund Landau, Hermann Weyl, and Felix Klein; physics under Voigt and Max Born; and philosophy under Leonard Nelson. In 1912, the University of Berlin awarded him a Ph.D. in mathematics for a thesis, supervised by Landau, on the analytic number theory of binary quadratic forms. That same year, the University of Zurich awarded him habilitation for a thesis on complex analysis and Picard's theorem. The examiner was Ernst Zermelo. Bernays was Privatdozent at the University of Zurich, 1912–17, where he came to know George Pólya. His collected communications with Kurt Gödel span many decades. Starting in 1917, David Hilbert employed Bernays to a
https://en.wikipedia.org/wiki/Schur%27s%20Inequality
In mathematics, Schur's inequality, named after Issai Schur, establishes that for all non-negative real numbers x, y, z, and t>0, with equality if and only if x = y = z or two of them are equal and the other is zero. When t is an even positive integer, the inequality holds for all real numbers x, y and z. When , the following well-known special case can be derived: Proof Since the inequality is symmetric in we may assume without loss of generality that . Then the inequality clearly holds, since every term on the left-hand side of the inequality is non-negative. This rearranges to Schur's inequality. Extensions A generalization of Schur's inequality is the following: Suppose a,b,c are positive real numbers. If the triples (a,b,c) and (x,y,z) are similarly sorted, then the following inequality holds: In 2007, Romanian mathematician Valentin Vornicu showed that a yet further generalized form of Schur's inequality holds: Consider , where , and either or . Let , and let be either convex or monotonic. Then, The standard form of Schur's is the case of this inequality where x = a, y = b, z = c, k = 1, ƒ(m) = mr. Another possible extension states that if the non-negative real numbers with and the positive real number t are such that x + v ≥ y + z then Notes Inequalities Articles containing proofs
https://en.wikipedia.org/wiki/Sherman%E2%80%93Morrison%20formula
In mathematics, in particular linear algebra, the Sherman–Morrison formula, named after Jack Sherman and Winifred J. Morrison, computes the inverse of the sum of an invertible matrix and the outer product, , of vectors and . The Sherman–Morrison formula is a special case of the Woodbury formula. Though named after Sherman and Morrison, it appeared already in earlier publications. Statement Suppose is an invertible square matrix and are column vectors. Then is invertible iff . In this case, Here, is the outer product of two vectors and . The general form shown here is the one published by Bartlett. Proof () To prove that the backward direction is invertible with inverse given as above) is true, we verify the properties of the inverse. A matrix (in this case the right-hand side of the Sherman–Morrison formula) is the inverse of a matrix (in this case ) if and only if . We first verify that the right hand side () satisfies . To end the proof of this direction, we need to show that in a similar way as above: (In fact, the last step can be avoided since for square matrices and , is equivalent to .) () Reciprocally, if , then via the matrix determinant lemma, , so is not invertible. Application If the inverse of is already known, the formula provides a numerically cheap way to compute the inverse of corrected by the matrix (depending on the point of view, the correction may be seen as a perturbation or as a rank-1 update). The computation is relative
https://en.wikipedia.org/wiki/Lionel%20Tarassenko
Lionel Tarassenko, (born 17 April 1957) is a British engineer and academic, who is a leading expert in the application of signal processing and machine learning to healthcare. Tarassenko is President of Reuben College, Oxford. He was previously Head of Department of Engineering Science (Dean of Engineering) at the University of Oxford, succeeded by Ronald A. Roy. Towards the end of his time as Dean, the Department rose to number 1 in the Times Higher Education World University Rankings. Tarassenko was elected Professor of Electrical Engineering at the University of Oxford in 1997 and was a Professorial Fellow of St John's College, Oxford, from 1997 to 2019. In 2019 he was invited by the Vice-Chancellor Louise Richardson to oversee the development of Reuben College, the University's 39th college. He is also a Pro-Vice Chancellor and the Chair of the Management Committee of the Maison Française d’Oxford. Tarassenko is the author of over 280 journal papers, 200 conference papers, 3 books and over 30 granted patents. He has supervised 65 doctoral students. He has been a founder director of four University spin-out companies, the latest being Oxehealth in September 2012. He was the R&D Director and Chair of the Strategic Advisory Board of Sensyne Health, an AIM-listed company from 2018 to 2022. He is a director of the University’s wholly owned Technology Transfer company, Oxford University Innovation. He was the editor-in-chief of the 2018 Topol Review of NHS Technology and i
https://en.wikipedia.org/wiki/Ira%20Glasser
Ira Saul Glasser (born April 18, 1938) served as the fifth executive director of the American Civil Liberties Union (ACLU) from 1978 to 2001. His life was the subject of the 2020 documentary Mighty Ira. Early years Ira Glasser was born on April 18, 1938, at Brooklyn Jewish Hospital in Brooklyn, New York. He earned a graduate degree in mathematics from Ohio State University. Early career In the early 1960s, Glasser taught mathematics at Queens College (CUNY) and Sarah Lawrence College. From 1963 to 1967, he was the editor of Current magazine. In 1967, Glasser joined the New York Civil Liberties Union as associate director. In 1970 he became the NYCLU's executive director, in which capacity he served until he became the executive director of the American Civil Liberties Union in 1978. Executive director The ACLU website credits Glasser with transforming the American Civil Liberties Union "from a 'mom and pop'-style operation concentrated mainly in a few large cities to a nationwide civil liberties powerhouse." At the end of Glasser's directorship the ACLU maintained staffed offices in all fifty states, the District of Columbia, and Puerto Rico; when he became director in 1978, only about half of the states had staffed offices. Glasser raised the ACLU's annual income from $4 million in 1978 to $45 million in 1999. Although the ACLU had protected civil liberties generally through litigation, Glasser expanded the focus of the ACLU's activities through lobbying and public ed
https://en.wikipedia.org/wiki/DNIC
DNIC can stand for: Dirección Nacional de Inteligencia Criminal Data Network Identification Code Diffuse noxious inhibitory controls In Christianity, Dominus Noster Iesus Christus (and other grammatical variants; "Our Lord Jesus Christ") In biochemistry, dinitrosyl iron complex Direcção nacional de investigação criminal (Angola) DoD Network Information Center pt:Polícia Nacional (Angola)#Órgãos centrais