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https://en.wikipedia.org/wiki/Bertrand%20Halperin
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Bertrand I. Halperin (born December 6, 1941) is an American physicist, former holder of the Hollis Chair of Mathematicks and Natural Philosophy at the physics department of Harvard University.
Biography
Halperin was born in Brooklyn, New York, where he grew up in the Crown Heights neighborhood and attended public schools. His mother was Eva Teplitzky Halperin and his father Morris Halperin. His mother was a college administrator and his father a customs inspector. Both his parents were born in USSR. His paternal grandmother's family the Maximovs claimed descent from Rabbi Israel Baal Shem Tov, the BESHT.
He attended Harvard University (class of 1961), and did his graduate work at the University of California, Berkeley, with John J. Hopfield (PhD 1965). After working at Bell Laboratories for 10 years (1966–1976), Murray Hill, New Jersey he was appointed professor of physics at Harvard University.
In the 1970s, he, together with David R. Nelson, worked out a theory of two-dimensional melting, predicting the hexatic phase before it was experimentally observed by Pindak et al. In the 1980s, he made contributions to the theory of the Quantum Hall Effect and of the Fractional Quantum Hall Effect. His recent interests lie in the area of strongly interacting low-dimensional electron systems.<ref name="
Halperin was elected a Fellow of the American Physical Society in 1972, a member of the American Academy of Arts and Sciences in 1981, a member of the National Academy of Sciences
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https://en.wikipedia.org/wiki/Woodie%20Flowers
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Woodie Claude Flowers (November 18, 1943 – October 11, 2019) was a professor of mechanical engineering at the Massachusetts Institute of Technology. His specialty areas were engineering design and product development; he held the Pappalardo Professorship and was a MacVicar Faculty Fellow.
Flowers was known for co-creating FIRST, a youth organization known primarily for operating FIRST Robotics Competition and other student engineering competitions. Working with inventor Dean Kamen, Flowers helped design the organization's competition structure based loosely around his 2.70 class at MIT.
Early life
Flowers was born in Jena, Louisiana on November 18, 1943, and named after his grandfathers Woodie and Claude. His father, Abe Flowers, was a welder and inventor; his mother, Bertie Graham, was an elementary-school and special education teacher. Flowers had a sister, Kay. As a boy, he showed mechanical aptitude like his father, Abe, and he earned the rank of Eagle Scout. When he was seventeen, he and four friends were driving on Louisiana Highway 127 when they were hit head-on by another vehicle that was traveling at about . The collision killed two people in Flowers' vehicle and one in the other. The event ingrained his self-described "genetic opposition to violence" and his "fierce, vocal loathing of any spectacle that involves crashing pieces of machinery into each other with deliberate force."
Career
1961–1973: Education
Flowers initially expected not to attend college, but a
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https://en.wikipedia.org/wiki/Alain%20Aspect
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Alain Aspect (; born 15 June 1947) is a French physicist noted for his experimental work on quantum entanglement.
Aspect was awarded the 2022 Nobel Prize in Physics, jointly with John Clauser and Anton Zeilinger, "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science".
Education
Aspect is a graduate of the École Normale Supérieure de Cachan (ENS Cachan, today part of Paris-Saclay University). He passed the agrégation in physics in 1969 and received his PhD degree in 1971 from the École supérieure d'optique (later known as Institut d'Optique Graduate School) of Université d'Orsay (later known as Université Paris-Sud). He then taught for three years in Cameroon as a replacement for then compulsory military service.
In the early 1980s, while working on his doctorat d'État (habilitation thesis), he performed the Bell test experiments that showed that Albert Einstein, Boris Podolsky and Nathan Rosen's putative reductio ad absurdum of quantum mechanics, namely that it implied 'ghostly action at a distance', did in fact appear to be realized when two particles were separated by an arbitrarily large distance (see EPR paradox and Aspect's experiment). A correlation between the particles' wave functions remains, as long as they were once part of the same undisturbed wave function before one of the child particles was measured. He defended his doctorat d'État in 1983 at Université Paris-Sud (today part of P
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https://en.wikipedia.org/wiki/Chemically%20peculiar%20star
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In astrophysics, chemically peculiar stars (CP stars) are stars with distinctly unusual metal abundances, at least in their surface layers.
Classification
Chemically peculiar stars are common among hot main-sequence (hydrogen-burning) stars. These hot peculiar stars have been divided into 4 main classes on the basis of their spectra, although two classification systems are sometimes used:
non-magnetic metallic-lined (Am, CP1)
magnetic (Ap, CP2)
non-magnetic mercury-manganese (HgMn, CP3)
helium-weak (He-weak, CP4).
The class names provide a good idea of the peculiarities that set them apart from other stars on or near the main sequence.
The Am stars (CP1 stars) show weak lines of singly ionized Ca and/or Sc, but show enhanced abundances of heavy metals. They also tend to be slow rotators and have an effective temperature between 7000 and .
The Ap stars (CP2 stars) are characterized by strong magnetic fields, enhanced abundances of elements such as Si, Cr, Sr and Eu, and are also generally slow rotators. The effective temperature of these stars is stated to be between 8000 and , but the issue of calculating effective temperatures in such peculiar stars is complicated by atmospheric structure.
The HgMn stars (CP3 stars) are also classically placed within the Ap category, but they do not show the strong magnetic fields associated with classical Ap stars. As the name implies, these stars show increased abundances of singly ionized Hg and Mn. These stars are also very
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https://en.wikipedia.org/wiki/Jozef%20Len%C3%A1rt
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Jozef Lenárt (3 April 1923 – 11 February 2004) was a Slovak politician who was the prime minister of Czechoslovakia from 1963 to 1968.
Life and career
Born in Liptovská Porúbka, Slovakia, he graduated from a chemistry high school and worked for the Baťa company. He became a member of the Communist Party of Czechoslovakia (KSČ) and of the Communist Party of Slovakia (KSS).
Lenart was a member of the federal parliament (whose name changed several times) from 1960 to 1990, and was Speaker of the Slovak National Council from 1962 to 1963. He was also a member from 1971 to (?)1990. He served as Prime Minister of Czechoslovakia between 1963 and 1968.
Although ethnically Slovak, he became a Czech citizen after the country split in 1993.
On the basis of insufficient evidence, on 23 September 2002 Lenárt was acquitted of treason charges (along with his co-defendant Miloš Jakeš), related to his handling (or lack thereof) of the Prague Spring events in 1968. He was accused of attending a meeting at the Soviet embassy in Prague on the day after the 1968 Warsaw Pact invasion, planning to establish a new "workers and farmers'" government.
Jozef Lenárt was one of the most resilient figures in Czechoslovakia's communist hierarchy, occupying one post or another in the leadership for no less than a quarter of the century. That achievement was all the more remarkable because his career at the top straddled a succession of regimes and several abrupt changes in policy.
He died in Prague in
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https://en.wikipedia.org/wiki/Bootstrap%20aggregating
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Bootstrap aggregating, also called bagging (from bootstrap aggregating), is a machine learning ensemble meta-algorithm designed to improve the stability and accuracy of machine learning algorithms used in statistical classification and regression. It also reduces variance and helps to avoid overfitting. Although it is usually applied to decision tree methods, it can be used with any type of method. Bagging is a special case of the model averaging approach.
Description of the technique
Given a standard training set of size n, bagging generates m new training sets , each of size n′, by sampling from D uniformly and with replacement. By sampling with replacement, some observations may be repeated in each . If n′=n, then for large n the set is expected to have the fraction (1 - 1/e) (≈63.2%) of the unique examples of D, the rest being duplicates. This kind of sample is known as a bootstrap sample. Sampling with replacement ensures each bootstrap is independent from its peers, as it does not depend on previous chosen samples when sampling. Then, m models are fitted using the above m bootstrap samples and combined by averaging the output (for regression) or voting (for classification).
Bagging leads to "improvements for unstable procedures", which include, for example, artificial neural networks, classification and regression trees, and subset selection in linear regression. Bagging was shown to improve preimage learning. On the other hand, it can mildly degrade the performa
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https://en.wikipedia.org/wiki/Mixing%20%28mathematics%29
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In mathematics, mixing is an abstract concept originating from physics: the attempt to describe the irreversible thermodynamic process of mixing in the everyday world: e.g. mixing paint, mixing drinks, industrial mixing.
The concept appears in ergodic theory—the study of stochastic processes and measure-preserving dynamical systems. Several different definitions for mixing exist, including strong mixing, weak mixing and topological mixing, with the last not requiring a measure to be defined. Some of the different definitions of mixing can be arranged in a hierarchical order; thus, strong mixing implies weak mixing. Furthermore, weak mixing (and thus also strong mixing) implies ergodicity: that is, every system that is weakly mixing is also ergodic (and so one says that mixing is a "stronger" condition than ergodicity).
Informal explanation
The mathematical definition of mixing aims to capture the ordinary every-day process of mixing, such as mixing paints, drinks, cooking ingredients, industrial process mixing, smoke in a smoke-filled room, and so on. To provide the mathematical rigor, such descriptions begin with the definition of a measure-preserving dynamical system, written as .
The set is understood to be the total space to be filled: the mixing bowl, the smoke-filled room, etc. The measure is understood to define the natural volume of the space and of its subspaces. The collection of subspaces is denoted by , and the size of any given subset is ; the size is it
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https://en.wikipedia.org/wiki/P%20system
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For the computer p-System, see UCSD p-System.
A P system is a computational model in the field of computer science that performs calculations using a biologically inspired process. They are based upon the structure of biological cells, abstracting from the way in which chemicals interact and cross cell membranes. The concept was first introduced in a 1998 report by the computer scientist Gheorghe Păun, whose last name is the origin of the letter P in 'P Systems'. Variations on the P system model led to the formation of a branch of research known as 'membrane computing.'
Although inspired by biology, the primary research interest in P systems is concerned with their use as a computational model, rather than for biological modeling, although this is also being investigated.
Informal description
A P system is defined as a series of membranes containing chemicals (in finite quantities), catalysts and rules which determine possible ways in which chemicals may react with one another to form products. Rules may also cause chemicals to pass through membranes or even cause membranes to dissolve.
Just as in a biological cell, where a chemical reaction may only take place upon the chance event that the required chemical molecules collide and interact (possibly also with a catalyst), the rules in a P system are applied at random. This causes the computation to proceed in a non-deterministic manner, often resulting in multiple solutions being encountered if the computation is repeated
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https://en.wikipedia.org/wiki/Edward%20Tsang
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Edward Tsang is a Computer Science professor at the University of Essex. He holds a first degree in Business Administration (major in Finance) from the Chinese University of Hong Kong (1977), and an MSc and PhD in Computer Science from the University of Essex (1983 and 1987). Prior to his PhD studies, he served for five
years in various positions in the commercial sector in Hong Kong.
Edward Tsang is the Director (and co-founder) of Centre for Computational Finance and Economic Agents (CCFEA) at University of Essex.
CCFEA is an interdisciplinary
research centre, which applies artificial intelligence methods to problems in finance and economics.
Edward Tsang is the author of Foundations of Constraint Satisfaction, the first book to define the scope of the field. He is also the co-author of Vehicle Scheduling in Port Automation (with Hassan Rashidi) and Evolutionary Applications for Financial Prediction: Classification Methods to Gather Patterns Using Genetic Programming (with Alma Garcia Almanza).
Edward Tsang founded the Computation Finance and Economics Technical Committee in IEEE’s Computational Intelligence Society in 2004, and chaired it until the end of 2005.
Edward Tsang specializes in business application of artificial intelligence. His research interests include artificial intelligence applications, computational finance, constraint satisfaction, evolutionary computation, and heuristic search.
He has given consultation to GEC Marconi, British Telecom, the Comm
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https://en.wikipedia.org/wiki/Imputation
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Imputation can refer to:
Imputation (law), the concept that ignorance of the law does not excuse
Imputation (statistics), substitution of some value for missing data
Imputation (genetics), estimation of unmeasured genotypes
Theory of imputation, the theory that factor prices are determined by output prices
Imputation (game theory), a distribution that benefits each player who cooperates in a game
Imputed righteousness, a concept in Christian theology
Double imputation, a concept in Christian theology
Imputation of sin, a theory for the transmission of original sin from Adam to his progeny
See also
Geo-imputation, a method in geographical information systems
Dividend imputation, a method of attributing a company's income tax to its shareholders
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https://en.wikipedia.org/wiki/Acetabularia
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Acetabularia is a genus of green algae in the family Polyphysaceae. Typically found in subtropical waters, Acetabularia is a single-celled organism, but gigantic in size and complex in form, making it an excellent model organism for studying cell biology. In form, the mature Acetabularia resembles the round leaves of a nasturtium, is tall and has three anatomical parts: a bottom rhizoid that resembles a set of short roots; a long stalk in the middle; and a top umbrella of branches that may fuse into a cap. Unlike other giant unicellular organisms, which are multinucleate, members of this genus a single nucleus located in the rhizoid and allows the cell to regenerate completely if its cap is removed. The caps of two Acetabularia may also be exchanged, even from two different species. In addition, if a piece of the stem is removed, with no access to the nucleus in the rhizoid, this isolated stem piece will also grow a new cap.
In the 1930s–1950s Joachim Hämmerling conducted experiments in which he demonstrated Acetabularias genetic information is contained in the nucleus. This was the first demonstration that genes are encoded by DNA in eukaryotes; earlier studies by Oswald Avery and others had shown that this was true for prokaryote
Etymology
The name, Acetabularia, derives from the Latin word acetabulum, a broad, shallow cup used for dipping bread; the upturned cap of Acetabularia resembles such a cup. For this reason, it is also sometimes called mermaid's wineglass.
In t
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https://en.wikipedia.org/wiki/Ivar%20Asbj%C3%B8rn%20F%C3%B8lling
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Ivar Asbjørn Følling (23 August 1888 – 24 January 1973) was a Norwegian physician and biochemist. He first described the disease commonly known as Følling's disease or phenylketonuria (PKU).
Career
He was born at Kvam, Steinkjer in Trøndelag, Norway. Følling studied chemistry at the Norwegian Institute of Technology in Trondheim and graduated in 1916. He then went to the University of Kristiania (now University of Oslo), graduating in medicine in 1922.
He received his cand.med. in 1929 after doing postgraduate work in Norway and abroad in Denmark, England, Vienna and the U.S. Starting in 1932, Følling occupied a series of medical posts in Oslo, culminating in his being Professor of Biochemistry and Physician-in-Chief at the central laboratory at the Norwegian national research hospital Oslo University Hospital. Følling was a professor of biochemistry at the University of Oslo for more than 30 years. He retired in 1958.
Discovery
In 1934 at Oslo University Hospital, Følling saw a young woman named Borgny Egeland. She had two children, Liv and Dag, who had been normal at birth but subsequently developed mental retardation. When Dag was about a year old, the mother noticed a strong smell to his urine. Følling obtained urine samples from the children and, after many tests, he found that the substance causing the odor in the urine was phenylpyruvic acid. The children, he concluded, had excess phenylpyruvic acid in the urine, the condition which came to be called phenylketonu
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https://en.wikipedia.org/wiki/Osgood
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Osgood may refer to:
Places in the United States
Osgood, Idaho
Osgood, Indiana
Osgood, Iowa
Osgood, Missouri
Osgood, North Dakota
Osgood, Ohio
Osgood, West Virginia
Other uses
Osgood (surname)
Osgood curve, in mathematics
See also
Osgood–Schlatter disease
Osgoode (disambiguation)
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https://en.wikipedia.org/wiki/Jean-Marie%20Lehn
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Jean-Marie Lehn (born 30 September 1939) is a French chemist. He received the Nobel Prize in Chemistry together with Donald Cram and Charles Pedersen in 1987 for his synthesis of cryptands. Lehn was an early innovator in the field of supramolecular chemistry, i.e., the chemistry of host–guest molecular assemblies created by intermolecular interactions, and continues to innovate in this field. He described the process by which molecules recognize each other. Drugs, for example, "know" which cell to destroy and which to let live. his group has published 790 peer-reviewed articles in chemistry literature.
Biography
Early years
Lehn was born in Rosheim, Alsace, France to Pierre and Marie Lehn. He is of Alsatian German descent. His father was a baker, but because of his interest in music, he later became the city organist. Lehn also studied music, saying that it became his major interest after science. He has continued to play the organ throughout his professional career as a scientist. His high school studies in Obernai, from 1950 to 1957, included Latin, Greek, German, and English languages, French literature, and he later became very keen of both philosophy and science, particularly chemistry. In July 1957, he obtained the baccalauréat in philosophy, and in September of the same year, the baccalauréat in Natural Sciences.
At the University of Strasbourg, although he considered studying philosophy, he ended up taking courses in physical, chemical and natural sciences, attend
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https://en.wikipedia.org/wiki/Thomas%20Cech
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Thomas Robert Cech (born December 8, 1947) is an American chemist who shared the 1989 Nobel Prize in Chemistry with Sidney Altman, for their discovery of the catalytic properties of RNA. Cech discovered that RNA could itself cut strands of RNA, suggesting that life might have started as RNA. He found that RNA can not only transmit instructions, but also that it can speed up the necessary reactions. He also studied telomeres, and his lab discovered an enzyme, TERT (telomerase reverse transcriptase), which is part of the process of restoring telomeres after they are shortened during cell division. As president of Howard Hughes Medical Institute, he promoted science education, and he teaches an undergraduate chemistry course at the University of Colorado.
Early life and career
Cech was born to parents of Czech origin (his grandfather was Czech, his other grandparents were first-generation Americans) in Chicago. He grew up in Iowa City, Iowa. In junior high school, he knocked on the doors of geology professors at the University of Iowa, and asked them to discuss crystal structures, meteorites and fossils.
A National Merit Scholar, Cech entered Grinnell College in 1966. There he studied Homer's Odyssey, Dante's Inferno, constitutional history and chemistry. He married his organic chemistry lab partner, Carol Lynn Martinson, and graduated with a B.A. in 1970.
In 1975, Cech completed his PhD in chemistry at the University of California, Berkeley and in the same year, he entered t
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https://en.wikipedia.org/wiki/Advanced%20z-transform
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In mathematics and signal processing, the advanced z-transform is an extension of the z-transform, to incorporate ideal delays that are not multiples of the sampling time. It takes the form
where
T is the sampling period
m (the "delay parameter") is a fraction of the sampling period
It is also known as the modified z-transform.
The advanced z-transform is widely applied, for example to accurately model processing delays in digital control.
Properties
If the delay parameter, m, is considered fixed then all the properties of the z-transform hold for the advanced z-transform.
Linearity
Time shift
Damping
Time multiplication
Final value theorem
Example
Consider the following example where :
If then reduces to the transform
which is clearly just the z-transform of .
References
Transforms
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https://en.wikipedia.org/wiki/UNIVAC%20EXEC%20II
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EXEC II is a discontinued operating system developed for the UNIVAC 1107 by Computer Sciences Corporation (CSC) while under contract to UNIVAC to develop the machine's COBOL compiler. They developed EXEC II because Univac's EXEC I operating system development was late. Because of this the COBOL compiler was actually designed to run under EXEC II, not EXEC I as specified in the original contract.
EXEC II is a batch processing operating system that supports a single job stream with concurrent spooling.
See also
List of UNIVAC products
History of computing hardware
References
External links
EXEC 2
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https://en.wikipedia.org/wiki/Origin%20%28mathematics%29
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In mathematics, the origin of a Euclidean space is a special point, usually denoted by the letter O, used as a fixed point of reference for the geometry of the surrounding space.
In physical problems, the choice of origin is often arbitrary, meaning any choice of origin will ultimately give the same answer. This allows one to pick an origin point that makes the mathematics as simple as possible, often by taking advantage of some kind of geometric symmetry.
Cartesian coordinates
In a Cartesian coordinate system, the origin is the point where the axes of the system intersect. The origin divides each of these axes into two halves, a positive and a negative semiaxis. Points can then be located with reference to the origin by giving their numerical coordinates—that is, the positions of their projections along each axis, either in the positive or negative direction. The coordinates of the origin are always all zero, for example (0,0) in two dimensions and (0,0,0) in three.
Other coordinate systems
In a polar coordinate system, the origin may also be called the pole. It does not itself have well-defined polar coordinates, because the polar coordinates of a point include the angle made by the positive x-axis and the ray from the origin to the point, and this ray is not well-defined for the origin itself.
In Euclidean geometry, the origin may be chosen freely as any convenient point of reference.
The origin of the complex plane can be referred as the point where real axis and ima
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https://en.wikipedia.org/wiki/Selection%20rule
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In physics and chemistry, a selection rule, or transition rule, formally constrains the possible transitions of a system from one quantum state to another. Selection rules have been derived for electromagnetic transitions in molecules, in atoms, in atomic nuclei, and so on. The selection rules may differ according to the technique used to observe the transition. The selection rule also plays a role in chemical reactions, where some are formally spin-forbidden reactions, that is, reactions where the spin state changes at least once from reactants to products.
In the following, mainly atomic and molecular transitions are considered.
Overview
In quantum mechanics the basis for a spectroscopic selection rule is the value of the transition moment integral
where and are the wave functions of the two states, "state 1" and "state 2", involved in the transition, and is the transition moment operator. This integral represents the propagator (and thus the probability) of the transition between states 1 and 2; if the value of this integral is zero then the transition is "forbidden".
In practice, to determine a selection rule the integral itself does not need to be calculated: It is sufficient to determine the symmetry of the transition moment function
If the transition moment function is symmetric over all of the totally symmetric representation of the point group to which the atom or molecule belongs, then the integral's value is (in general) not zero and the transition is al
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https://en.wikipedia.org/wiki/Dirac%20comb
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In mathematics, a Dirac comb (also known as sha function, impulse train or sampling function) is a periodic function with the formula
for some given period . Here t is a real variable and the sum extends over all integers k. The Dirac delta function and the Dirac comb are tempered distributions. The graph of the function resembles a comb (with the s as the comb's teeth), hence its name and the use of the comb-like Cyrillic letter sha (Ш) to denote the function.
The symbol , where the period is omitted, represents a Dirac comb of unit period. This implies
Because the Dirac comb function is periodic, it can be represented as a Fourier series based on the Dirichlet kernel:
The Dirac comb function allows one to represent both continuous and discrete phenomena, such as sampling and aliasing, in a single framework of continuous Fourier analysis on tempered distributions, without any reference to Fourier series. The Fourier transform of a Dirac comb is another Dirac comb. Owing to the Convolution Theorem on tempered distributions which turns out to be the Poisson summation formula, in signal processing, the Dirac comb allows modelling sampling by multiplication with it, but it also allows modelling periodization by convolution with it.
Dirac-comb identity
The Dirac comb can be constructed in two ways, either by using the comb operator (performing sampling) applied to the function that is constantly , or, alternatively, by using the rep operator (performing periodization) ap
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https://en.wikipedia.org/wiki/NPN
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NPN may refer to:
Science and technology
Next Protocol Negotiation, in computer networking
Non-protein nitrogen, an animal feed component
NPN transistor
Normal Polish notation, in mathematics
Organisations
National Party of Nigeria, a former political party
New Politics Network, a UK think tank
Other uses
Natural Health Product Number, required by the Canadian Natural Health Products Directorate
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https://en.wikipedia.org/wiki/Downsampling%20%28signal%20processing%29
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In digital signal processing, downsampling, compression, and decimation are terms associated with the process of resampling in a multi-rate digital signal processing system. Both downsampling and decimation can be synonymous with compression, or they can describe an entire process of bandwidth reduction (filtering) and sample-rate reduction. When the process is performed on a sequence of samples of a signal or a continuous function, it produces an approximation of the sequence that would have been obtained by sampling the signal at a lower rate (or density, as in the case of a photograph).
Decimation is a term that historically means the removal of every tenth one. But in signal processing, decimation by a factor of 10 actually means keeping only every tenth sample. This factor multiplies the sampling interval or, equivalently, divides the sampling rate. For example, if compact disc audio at 44,100 samples/second is decimated by a factor of 5/4, the resulting sample rate is 35,280. A system component that performs decimation is called a decimator. Decimation by an integer factor is also called compression.
Downsampling by an integer factor
Rate reduction by an integer factor M can be explained as a two-step process, with an equivalent implementation that is more efficient:
Reduce high-frequency signal components with a digital lowpass filter.
Decimate the filtered signal by M; that is, keep only every Mth sample.
Step 2 alone creates undesirable aliasing (i.e. high-frequ
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https://en.wikipedia.org/wiki/Tunica
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Tunica may refer to:
The Latin word for tunic, a type of clothing typical in the ancient world
Biology
Tunica (biology), a layer, sheath or similar covering
"Tunica", an anatomical term for a membranous structure lining a cavity, or covering an organ such as a gland or a blood vessel
Tunica albuginea (disambiguation), three different layers of connective tissue
Tunica vasculosa (disambiguation), two different vascular layers
Tunica externa, outermost tunica (layer) of a blood vessel, surrounding the tunica media
Tunica intima, for short, is the innermost tunica (layer) of an artery or vein
Other
Tunica, a flowering plant genus now included in Petrorhagia
Tunica people, a Native American group in the central Mississippi River Valley
Tunica language, an isolate of the associated Tunica historic peoples in the central Mississippi River Valley
Tunica-Biloxi, a federally recognized tribe Native American tribe in Louisiana
Tunica, Louisiana
Tunica, Mississippi
Tunica County, Mississippi
Tunica Lake, Lee County, Arkansas and Tunica County, Mississippi
Tunica Academy, a non-denominational Christian private school
Tunica Resorts, Mississippi
See also
Language and nationality disambiguation pages
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https://en.wikipedia.org/wiki/E7
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E7, E07, E-7 or E7 may refer to:
Science and engineering
E7 liquid crystal mixture
E7, the Lie group in mathematics
E7 polytope, in geometry
E7 papillomavirus protein
E7 European long distance path
Transport
EMD E7, a diesel locomotive
European route E07, an international road
Peugeot E7, a hackney cab
PRR E7, a steam locomotive
Carbon Motors E7,a police car
E7 series, a Japanese high-speed train
Nihonkai-Tōhoku Expressway and Akita Expressway (between Kawabe JCT and Kosaka JCT), route E7 in Japan
Cheras–Kajang Expressway, route E7 in Malaysia
Other uses
Boeing E-7, either:
Boeing E-7 ARIA, the original designation assigned by the United States Air Force under the Mission Designation System to the EC-18B Advanced Range Instrumentation Aircraft.
Boeing E-7 Wedgetail, the designation assigned by the Royal Australian Air Force to the Boeing 737 AEW&C (airborne early warning and control) aircraft.
Economy 7, an electricity tariff
E-7 enlisted rank in the military of the United States
E7 (countries)
E7, a musical note in the seventh octave
E-7, the original designation for the EC-18 ARIA electronic warfare aircraft
E7, a postcode district in the E postcode area for east London
European Aviation Air Charter, by IATA airline designator
Nokia E7, a smart phone
Samsung Galaxy E7, a smart phone
E07, a number station allegedly used by Russia, and nicknamed "The English Man"
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https://en.wikipedia.org/wiki/Upsampling
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In digital signal processing, upsampling, expansion, and interpolation are terms associated with the process of resampling in a multi-rate digital signal processing system. Upsampling can be synonymous with expansion, or it can describe an entire process of expansion and filtering (interpolation). When upsampling is performed on a sequence of samples of a signal or other continuous function, it produces an approximation of the sequence that would have been obtained by sampling the signal at a higher rate (or density, as in the case of a photograph). For example, if compact disc audio at 44,100 samples/second is upsampled by a factor of 5/4, the resulting sample-rate is 55,125.
Upsampling by an integer factor
Rate increase by an integer factor L can be explained as a 2-step process, with an equivalent implementation that is more efficient:
Expansion: Create a sequence, comprising the original samples, separated by L − 1 zeros. A notation for this operation is:
Interpolation: Smooth out the discontinuities with a lowpass filter, which replaces the zeros.
In this application, the filter is called an interpolation filter, and its design is discussed below. When the interpolation filter is an FIR type, its efficiency can be improved, because the zeros contribute nothing to its dot product calculations. It is an easy matter to omit them from both the data stream and the calculations. The calculation performed by a multirate interpolating FIR filter for each output sample is
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https://en.wikipedia.org/wiki/152%20%28number%29
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152 (one hundred [and] fifty-two) is the natural number following 151 and preceding 153.
In mathematics
152 is the sum of four consecutive primes (31 + 37 + 41 + 43). It is a nontotient since there is no integer with 152 coprimes below it.
152 is a refactorable number since it is divisible by the total number of divisors it has, and in base 10 it is divisible by the sum of its digits, making it a Harshad number.
Recently, the smallest repunit probable prime in base 152 was found, it has 589570 digits.
The number of surface points on a 6*6*6 cube is 152.
In the military
Focke-Wulf Ta 152 was a Luftwaffe high-altitude interceptor fighter aircraft during World War II
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy supply ship during World War II
was a United States Navy during World War II
was a United States Navy ship during World War II
was a United States Navy during World War II
was a United States Navy during World War II
152.3 (5.9"), common medium artillery (and historically heavy tank destroyer) caliber utilized by Russia, China and former members of the Soviet Union, akin to the 155 mm standard caliber of NATO nations.
In transportation
The Baade 152, the first German jet passenger airliner in 1958
The Cessna 152 airplane
Garuda Indonesia Flight 152 was an Indonesian flight from Jakarta to Medan that crashed on September 26, 1997
London Buses route 152
In TV, radio, game
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https://en.wikipedia.org/wiki/Secant
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Secant is a term in mathematics derived from the Latin secare ("to cut"). It may refer to:
a secant line, in geometry
the secant variety, in algebraic geometry
secant (trigonometry) (Latin: secans), the multiplicative inverse (or reciprocal) trigonometric function of the cosine
the secant method, a root-finding algorithm in numerical analysis, based on secant lines to graphs of functions
a secant ogive in nose cone designsr:Секанс
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https://en.wikipedia.org/wiki/ZGB
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ZGB may refer to:
Swiss Civil Code
Zabergäu-Gymnasium Brackenheim, school in Germany
The Ziff–Gulari–Barshad model in chemical physics for the catalytic oxidation of carbon monoxide
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https://en.wikipedia.org/wiki/Khieu%20Rada
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Khieu Rada (born April 15, 1949 in Battambang) is a Cambodian politician. He is the son of Khieu In and Sing Tep.
Education
C final exam (1969), M.G.P. (Physical General mathematics - 1970)
S.P.C.N. (Sciences, Physical, Natural Chemistry), Master es Sciences (1973)
C.N.A.M. (General mathematics - 1982) in France
AFPA of analysis Programming and Teleprocessing (1982) in France
Engineer Conceptor (Cap Gemini)
Politics
President of the UPAKAF (Union of Patriots of the Kampuchea in France) in 1979
Founding member of the Confederation of the Khmers Nationalists with Norodom Sihanouk in 1979
Founding member of the FUNCINPEC in 1981 with Norodom Sihanouk
President Director of the FUNCINPEC Television (Channel 9) in 1992
Vice Minister of Relations with the Parliament of the G.N.P. in 1993
Advisor of the Prime Minister the Prince Norodom Ranariddh from 1993 to 1994
Honorary member of the Royal Cabinet with rank of Minister since the 28 January 1994
Under Secretary of State of the Trade Ministry of Cambodia from 1994 to 1995
Delegation Chief of Cambodia at United Nation Conference about Trade and Development
Secretary General of the Khmer National Party (renamed to Sam Rainsy Party) Cambodia from 1995 to 1997
President of the Khmer Unity Party (KUP) from 23 October 1997 to June 2006
Vice Deleguate General of the Sangkum Jatiniyum Front Party of Prince Sisowath Thomico from July 2006 to September 2007
President Adviser of Sam Rainsy Party from October 2007 to Janua
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https://en.wikipedia.org/wiki/Robot%20kinematics
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In robotics, robot kinematics applies geometry to the study of the movement of multi-degree of freedom kinematic chains that form the structure of robotic systems. The emphasis on geometry means that the links of the robot are modeled as rigid bodies and its joints are assumed to provide pure rotation or translation.
Robot kinematics studies the relationship between the dimensions and connectivity of kinematic chains and the position, velocity and acceleration of each of the links in the robotic system, in order to plan and control movement and to compute actuator forces and torques. The relationship between mass and inertia properties, motion, and the associated forces and torques is studied as part of robot dynamics.
Kinematic equations
A fundamental tool in robot kinematics is the kinematics equations of the kinematic chains that form the robot. These non-linear equations are used to map the joint parameters to the configuration of the robot system. Kinematics equations are also used in biomechanics of the skeleton and computer animation of articulated characters.
Forward kinematics uses the kinematic equations of a robot to compute the position of the end-effector from specified values for the joint parameters. The reverse process that computes the joint parameters that achieve a specified position of the end-effector is known as inverse kinematics. The dimensions of the robot and its kinematics equations define the volume of space reachable by the robot, known as
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https://en.wikipedia.org/wiki/Signalling%20theory
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Within evolutionary biology, signalling theory is a body of theoretical work examining communication between individuals, both within species and across species. The central question is when organisms with conflicting interests, such as in sexual selection, should be expected to provide honest signals (no presumption being made of conscious intention) rather than cheating. Mathematical models describe how signalling can contribute to an evolutionarily stable strategy.
Signals are given in contexts such as mate selection by females, which subjects the advertising males' signals to selective pressure. Signals thus evolve because they modify the behaviour of the receiver to benefit the signaller. Signals may be honest, conveying information which usefully increases the fitness of the receiver, or dishonest. An individual can cheat by giving a dishonest signal, which might briefly benefit that signaller, at the risk of undermining the signalling system for the whole population.
The question of whether the selection of signals works at the level of the individual organism or gene, or at the level of the group, has been debated by biologists such as Richard Dawkins, arguing that individuals evolve to signal and to receive signals better, including resisting manipulation. Amotz Zahavi suggested that cheating could be controlled by the handicap principle, where the best horse in a handicap race is the one carrying the largest handicap weight. According to Zahavi's theory, signaller
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https://en.wikipedia.org/wiki/172%20%28number%29
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172 (one hundred [and] seventy-two) is the natural number following 171 and preceding 173.
In mathematics
172 is a part of a near-miss for being a counterexample to Fermat's last theorem, as 1353 + 1383 = 1723 − 1. This is only the third near-miss of this form, two cubes adding to one less than a third cube. It is also a "thickened cube number", half an odd cube (73 = 343) rounded up to the next integer.
See also
172 (disambiguation)
References
Integers
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https://en.wikipedia.org/wiki/MSSM
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MSSM may refer to:
Maine School of Science and Mathematics
Minimal Supersymmetric Standard Model
Mount Sinai School of Medicine
Master of Science degree in Systems Management
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https://en.wikipedia.org/wiki/Stau
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Stau may refer to one of the following:
In particle physics, stau is a slepton which is the hypothetical superpartner of a tau lepton
An obsolete letter Stigma in the Greek alphabet
In German, stau is a word meaning 'traffic jam'
One common abbreviation of St. Augustine High School (disambiguation)
In the fictional Vulcan language, stau is the verb 'to kill'
An alternate name for the Horpa language
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https://en.wikipedia.org/wiki/Robert%20Bosch%20Jr.
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Robert Bosch Jr. (29 January 1928 in Stuttgart – 2 August 2004 in Gerlingen) was the son of Robert Bosch and owned together with his sister, Eva Madelung, 8% of Robert Bosch GmbH.
He studied electrical engineering in Stuttgart. He was married to Irmgard von Graevenitz. From 1971 to 1978 he was a member of the supervisory board.
External links
Forbes.com: Forbes World's Richest People Dead Link
Robert Bosch der Jüngere gestorben
Biography in Muzinger
German industrialists
German billionaires
1928 births
2004 deaths
Businesspeople from Stuttgart
20th-century German businesspeople
21st-century German businesspeople
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https://en.wikipedia.org/wiki/Missense%20mutation
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In genetics, a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. It is a type of nonsynonymous substitution.
Substitution of protein from DNA mutations
Missense mutation refers to a change in one amino acid in a protein, arising from a point mutation in a single nucleotide. Missense mutation is a type of nonsynonymous substitution in a DNA sequence. Two other types of nonsynonymous substitution are the nonsense mutations, in which a codon is changed to a premature stop codon that results in truncation of the resulting protein, and the nonstop mutations, in which a stop codon erasement results in a longer, nonfunctional protein.
Missense mutations can render the resulting protein nonfunctional, and such mutations are responsible for human diseases such as Epidermolysis bullosa, sickle-cell disease, SOD1 mediated ALS, and a substantial number of cancers.
In the most common variant of sickle-cell disease, the 20th nucleotide of the gene for the beta chain of hemoglobin is altered from the codon GAG to GTG. Thus, the 6th amino acid glutamic acid is substituted by valine—notated as an "E6V" mutation—and the protein is sufficiently altered to cause the sickle-cell disease.
Not all missense mutations lead to appreciable protein changes. An amino acid may be replaced by an amino acid of very similar chemical properties, in which case, the protein may still function normally; this is termed a neutra
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https://en.wikipedia.org/wiki/Homotopical%20algebra
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In mathematics, homotopical algebra is a collection of concepts comprising the nonabelian aspects of homological algebra, and possibly the abelian aspects as special cases. The homotopical nomenclature stems from the fact that a common approach to such generalizations is via abstract homotopy theory, as in nonabelian algebraic topology, and in particular the theory of closed model categories.
This subject has received much attention in recent years due to new foundational work of Vladimir Voevodsky, Eric Friedlander, Andrei Suslin, and others resulting in the A1 homotopy theory for quasiprojective varieties over a field. Voevodsky has used this new algebraic homotopy theory to prove the Milnor conjecture (for which he was awarded the Fields Medal) and later, in collaboration with Markus Rost, the full Bloch–Kato conjecture.
References
See also
Derived algebraic geometry
Derivator
Cotangent complex - one of the first objects discovered using homotopical algebra
L∞ Algebra
A∞ Algebra
Categorical algebra
Nonabelian homological algebra
External links
An abstract for a talk on the proof of the full Bloch–Kato conjecture
Algebraic topology
Topological methods of algebraic geometry
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https://en.wikipedia.org/wiki/Bartholomew%20Price
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Reverend Bartholomew Price (181829 December 1898) was an English mathematician, clergyman and educator.
Life
He was born at Coln St Denis, Gloucestershire, in 1818. He was educated at Pembroke College, Oxford, of which college (after taking a first class in mathematics in 1840 and gaining the university mathematical scholarship in 1842) he became fellow in 1844 and tutor and mathematical lecturer in 1845. He at once took a leading position in the mathematical teaching of the university, and published treatises on the Differential calculus (in 1848) and the Infinitesimal calculus (4 vols., 1852–1860), which for long were the recognized textbooks there. This latter work included the differential and integral calculus, the calculus of variations, the theory of attractions, and analytical mechanics.
In 1853, he was appointed Sedleian professor of natural philosophy, resigning it in June 1898. His chief public activity at Oxford was in connection with the Hebdomadal Council, and with the Clarendon Press, of which he was for many years secretary. He was also a curator of the Bodleian Library, an honorary fellow of the Queen's College, a governor of Winchester College and a visitor of Greenwich Observatory.
In 1891, he was elected Master of Pembroke College, which dignity carried with it a canonry of Gloucester Cathedral.
He also seems to have donated an interesting astronomical clock to Gloucester cathedral.
In 1889 he was one of the shareholders in Silver's factory in Silverto
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https://en.wikipedia.org/wiki/Quasi-projective%20variety
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In mathematics, a quasi-projective variety in algebraic geometry is a locally closed subset of a projective variety, i.e., the intersection inside some projective space of a Zariski-open and a Zariski-closed subset. A similar definition is used in scheme theory, where a quasi-projective scheme is a locally closed subscheme of some projective space.
Relationship to affine varieties
An affine space is a Zariski-open subset of a projective space, and since any closed affine subset can be expressed as an intersection of the projective completion and the affine space embedded in the projective space, this implies that any affine variety is quasiprojective. There are locally closed subsets of projective space that are not affine, so that quasi-projective is more general than affine. Taking the complement of a single point in projective space of dimension at least 2 gives a non-affine quasi-projective variety. This is also an example of a quasi-projective variety that is neither affine nor projective.
Examples
Since quasi-projective varieties generalize both affine and projective varieties, they are sometimes referred to simply as varieties. Varieties isomorphic to affine algebraic varieties as quasi-projective varieties are called affine varieties; similarly for projective varieties. For example, the complement of a point in the affine line, i.e., , is isomorphic to the zero set of the polynomial in the affine plane. As an affine set is not closed since any polynomial zero
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https://en.wikipedia.org/wiki/Integral%20curve
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In mathematics, an integral curve is a parametric curve that represents a specific solution to an ordinary differential equation or system of equations.
Name
Integral curves are known by various other names, depending on the nature and interpretation of the differential equation or vector field. In physics, integral curves for an electric field or magnetic field are known as field lines, and integral curves for the velocity field of a fluid are known as streamlines. In dynamical systems, the integral curves for a differential equation that governs a system are referred to as trajectories or orbits.
Definition
Suppose that F is a static vector field, that is, a vector-valued function with Cartesian coordinates (F1,F2,...,Fn), and that x(t) is a parametric curve with Cartesian coordinates (x1(t),x2(t),...,xn(t)). Then x(t) is an integral curve of F if it is a solution of the autonomous system of ordinary differential equations,
Such a system may be written as a single vector equation,
This equation says that the vector tangent to the curve at any point x(t) along the curve is precisely the vector F(x(t)), and so the curve x(t) is tangent at each point to the vector field F.
If a given vector field is Lipschitz continuous, then the Picard–Lindelöf theorem implies that there exists a unique flow for small time.
Examples
If the differential equation is represented as a vector field or slope field, then the corresponding integral curves are tangent to the field at each point
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https://en.wikipedia.org/wiki/Hartmut%20Michel
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Hartmut Michel (; born 18 July 1948) is a German biochemist, who received the 1988 Nobel Prize in Chemistry for determination of the first crystal structure of an integral membrane protein, a membrane-bound complex of proteins and co-factors that is essential to photosynthesis.
Education and early life
He was born on 18 July 1948 in Ludwigsburg. After compulsory military service, he studied biochemistry at the University of Tübingen, working for his final year at Dieter Oesterhelt's laboratory on ATPase activity of halobacteria.
Career and research
Hartmut later worked on the crystallisation of membrane proteins – essential for their structure elucidation by X-ray crystallography. He received the Nobel Prize jointly with Johann Deisenhofer and Robert Huber in 1988. Together with Michel and Huber, Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple type of photosynthesis. Between 1982 and 1985, the three scientists used X-ray crystallography to determine the exact arrangement of the more than 10,000 atoms that make up the protein complex. Their research increased the general understanding of the mechanisms of photosynthesis, revealed similarities between the photosynthetic processes of plants and bacteria and established a methodology for crystallising membrane proteins.
Since 1987 h
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https://en.wikipedia.org/wiki/Chloralose
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Chloralose (also known as α-chloralose) is an avicide, and a rodenticide used to kill mice in temperatures below 15 °C. It is also widely used in neuroscience and veterinary medicine as an anesthetic and sedative. Either alone or in combination, such as with urethane, it is used for long-lasting, but light anesthesia.
Chemically, it is a chlorinated acetal derivative of glucose.
It is listed in Annex I of Directive 67/548/EEC with the classification Harmful (Xn)
Chloralose exerts barbiturate-like actions on synaptic transmission in the brain, including potent effects at inhibitory γ-aminobutyric acid type A receptors (GABAAR). A structural isomer of chloralose, β-chloralose (also called parachloralose in older literature), is inactive as a GABAAR modulator and also as a general anesthetic.
Chloralose is often abused for its avicide properties. In the United Kingdom, protected birds of prey have been killed using the chemical.
Legal use for bird control also often causes raptor mortalities from secondary poisoning, as well as primary poisoning of non-target species from eating bait, for example, kererū pigeon in New Zealand.
References
Acetals
Polyols
Monosaccharide derivatives
Rodenticides
Avicides
GABAA receptor positive allosteric modulators
Sedatives
General anesthetics
Trichloromethyl compounds
Heterocyclic compounds with 2 rings
Oxygen heterocycles
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https://en.wikipedia.org/wiki/David%20Singmaster
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David Breyer Singmaster (14 December 1938 – 13 February 2023) was an American-British mathematician who was emeritus professor of mathematics at London South Bank University, England. He had a huge personal collection of mechanical puzzles and books of brain teasers. He was most famous for being an early adopter and enthusiastic promoter of the Rubik's Cube. His Notes on Rubik's "Magic Cube" which he began compiling in 1979 provided the first mathematical analysis of the Cube as well as providing one of the first published solutions. The book contained his cube notation which allowed the recording of Rubik's Cube moves, and which quickly became the standard.
Singmaster was both a puzzle historian and a composer of puzzles, and many of his puzzles were published in newspapers and magazines. In combinatorial number theory, Singmaster's conjecture states that there is an upper bound on the number of times a number other than 1 can appear in Pascal's triangle.
Career
David Singmaster was a student at the California Institute of Technology in the late 1950s. His intention was to become a civil engineer, but he became interested in chemistry and then physics. However he was thrown out of college in his third year for "lack of academic ability". After a year working, he switched to the University of California, Berkeley. He only became really interested in mathematics in his final year when he took some courses in algebra and number theory. In the autumn semester, his number theor
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https://en.wikipedia.org/wiki/Rapid%20amplification%20of%20cDNA%20ends
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Rapid amplification of cDNA ends (RACE) is a technique used in molecular biology to obtain the full length sequence of an RNA transcript found within a cell. RACE results in the production of a cDNA copy of the RNA sequence of interest, produced through reverse transcription, followed by PCR amplification of the cDNA copies (see RT-PCR). The amplified cDNA copies are then sequenced and, if long enough, should map to a unique genomic region. RACE is commonly followed up by cloning before sequencing of what was originally individual RNA molecules. A more high-throughput alternative which is useful for identification of novel transcript structures, is to sequence the RACE-products by next generation sequencing technologies.
Process
RACE can provide the sequence of an RNA transcript from a small known sequence within the transcript to the 5' end (5' RACE-PCR) or 3' end (3' RACE-PCR) of the RNA. This technique is sometimes called one-sided PCR or anchored PCR.
The first step in RACE is to use reverse transcription to produce a cDNA copy of a region of the RNA transcript. In this process, an unknown end portion of a transcript is copied using a known sequence from the center of the transcript. The copied region is bounded by the known sequence, at either the 5' or 3' end.
The protocols for 5' or 3' RACES differ slightly. 5' RACE-PCR begins using mRNA as a template for a first round of cDNA synthesis (or reverse transcription) reaction using an anti-sense (reverse) oligonucleo
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https://en.wikipedia.org/wiki/Richard%20C.%20Tolman
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Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an American mathematical physicist and physical chemist who made many contributions to statistical mechanics. He also made important contributions to theoretical cosmology in the years soon after Einstein's discovery of general relativity. He was a professor of physical chemistry and mathematical physics at the California Institute of Technology (Caltech).
Biography
Tolman was born in West Newton, Massachusetts and studied chemical engineering at the Massachusetts Institute of Technology, receiving his bachelor's degree in 1903 and PhD in 1910 under A. A. Noyes.
He married Ruth Sherman Tolman in 1924.
In 1912, he conceived of the concept of relativistic mass, writing that "the expression is best suited for the mass of a moving body."
In a 1916 experiment with Thomas Dale Stewart, Tolman demonstrated that electricity consists of electrons flowing through a metallic conductor. A by-product of this experiment was a measured value of the mass of the electron. Overall, however, he was primarily known as a theorist.
Tolman was a member of the Technical Alliance in 1919, a forerunner of the Technocracy movement where he helped conduct an energy survey analyzing the possibility of applying science to social and industrial affairs.
Tolman was elected a Fellow of the American Academy of Arts and Sciences in 1922. The same year, he joined the faculty of the California Institute of Technology, where he became professor
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https://en.wikipedia.org/wiki/Markov%20random%20field
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In the domain of physics and probability, a Markov random field (MRF), Markov network or undirected graphical model is a set of random variables having a Markov property described by an undirected graph. In other words, a random field is said to be a Markov random field if it satisfies Markov properties. The concept originates from the Sherrington–Kirkpatrick model.
A Markov network or MRF is similar to a Bayesian network in its representation of dependencies; the differences being that Bayesian networks are directed and acyclic, whereas Markov networks are undirected and may be cyclic. Thus, a Markov network can represent certain dependencies that a Bayesian network cannot (such as cyclic dependencies ); on the other hand, it can't represent certain dependencies that a Bayesian network can (such as induced dependencies ). The underlying graph of a Markov random field may be finite or infinite.
When the joint probability density of the random variables is strictly positive, it is also referred to as a Gibbs random field, because, according to the Hammersley–Clifford theorem, it can then be represented by a Gibbs measure for an appropriate (locally defined) energy function. The prototypical Markov random field is the Ising model; indeed, the Markov random field was introduced as the general setting for the Ising model. In the domain of artificial intelligence, a Markov random field is used to model various low- to mid-level tasks in image processing and computer vision.
Def
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https://en.wikipedia.org/wiki/Yukawa%20interaction
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In particle physics, Yukawa's interaction or Yukawa coupling, named after Hideki Yukawa, is an interaction between particles according to the Yukawa potential. Specifically, it is a scalar field (or pseudoscalar field) and a Dirac field of the type
The Yukawa interaction was developed to model the strong force between hadrons. A Yukawa interaction is thus used to describe the nuclear force between nucleons mediated by pions (which are pseudoscalar mesons).
A Yukawa interaction is also used in the Standard Model to describe the coupling between the Higgs field and massless quark and lepton fields (i.e., the fundamental fermion particles). Through spontaneous symmetry breaking, these fermions acquire a mass proportional to the vacuum expectation value of the Higgs field. This Higgs-fermion coupling was first described by Steven Weinberg in 1967 to model lepton masses.
Classical potential
If two fermions interact through a Yukawa interaction mediated by a Yukawa particle of mass , the potential between the two particles, known as the Yukawa potential, will be:
which is the same as a Coulomb potential except for the sign and the exponential factor. The sign will make the interaction attractive between all particles (the electromagnetic interaction is repulsive for same electrical charge sign particles). This is explained by the fact that the Yukawa particle has spin zero and even spin always results in an attractive potential. (It is a non-trivial result of quantum field t
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https://en.wikipedia.org/wiki/Klaus%20Tschira
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Klaus Tschira (7 December 1940 – 31 March 2015) was a German billionaire entrepreneur and the co-founder of the German software company SAP AG.
Life
After gaining his Diplom in physics and working at IBM, Tschira co-founded the German software giant SAP AG in 1972 in Mannheim, Germany together with Hans-Werner Hector, Dietmar Hopp, Hasso Plattner and Claus Wellenreuther. From 1998 to 2007, he was a board member at SAP. He was married to Gerda Tschira and had two sons, Harald and Udo.
He died on 31 March 2015 in Heidelberg.
Klaus Tschira Foundation
The Klaus Tschira Foundation (KTF) was established by Tschira in 1995 as a non-profit organization. Its primary objective is to support projects in natural and computer sciences as well as mathematics. The KTF places strong emphasis on public understanding in these fields. Tschira's commitment to this objective was honored in 1999 with the "Deutscher Stifterpreis" by the German National Academic Foundation (German: Studienstiftung). The KTF is located at the Villa Bosch in Heidelberg, Germany, the former residence of Nobel Prize laureate for chemistry Carl Bosch (1874–1940).
Gerda and Klaus Tschira Foundation
In 2008, Tschira and his wife Gerda founded the Gerda and Klaus Tschira Foundation.
Honors
1995: Honorary doctorate of the University of Klagenfurt
1997: Honorary senator of the University of Heidelberg
1999: Order of Merit of the Federal Republic of Germany (Verdienstkreuz am Bande)
1999: Honorary senator of the
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https://en.wikipedia.org/wiki/Message%20passing
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In computer science, message passing is a technique for invoking behavior (i.e., running a program) on a computer. The invoking program sends a message to a process (which may be an actor or object) and relies on that process and its supporting infrastructure to then select and run some appropriate code. Message passing differs from conventional programming where a process, subroutine, or function is directly invoked by name. Message passing is key to some models of concurrency and object-oriented programming.
Message passing is ubiquitous in modern computer software. It is used as a way for the objects that make up a program to work with each other and as a means for objects and systems running on different computers (e.g., the Internet) to interact. Message passing may be implemented by various mechanisms, including channels.
Overview
Message passing is a technique for invoking behavior (i.e., running a program) on a computer. In contrast to the traditional technique of calling a program by name, message passing uses an object model to distinguish the general function from the specific implementations. The invoking program sends a message and relies on the object to select and execute the appropriate code. The justifications for using an intermediate layer essentially falls into two categories: encapsulation and distribution.
Encapsulation is the idea that software objects should be able to invoke services on other objects without knowing or caring about how those servic
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https://en.wikipedia.org/wiki/Korea%20Polytechnic%20III%20Chuncheon
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Chuncheon Polytechnic College is a vocational training institution located in Chuncheon City, the capital of Gangwon province, South Korea. The current president is Yeom Si Hwan.
Academics
Chuncheon Polytechnic offers technical training courses through its departments of Materials Science, Computer-aided Mechanics, Electricity, Electronics, Industrial Design, and Multimedia.
History
The school was founded in 1973 as Chuncheon Vocational Training Institute, operated by the South Korean Ministry of Labor. It was reorganized as a polytechnic college offering the bachelor's degree in 1996.
See also
Education in South Korea
List of colleges and universities in South Korea
External links
Official school website, in Korean
Vocational education in South Korea
Universities and colleges in Gangwon Province, South Korea
Korea Polytechnics
Chuncheon
Educational institutions established in 1973
1973 establishments in South Korea
ko:한국폴리텍3대학
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https://en.wikipedia.org/wiki/Samuel%20Menashe
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Samuel Menashe (September 16, 1925 – August 22, 2011) was an American poet.
Biography
Born in New York City as Samuel Menashe Weisberg, the son of Russian-Jewish immigrant parents, Menashe grew up in Elmhurst, Queens, and graduated from Townsend Harris High School and Queens College where he majored in biochemistry. During World War II he served in the US Army infantry, and in 1944 fought in the Battle of the Bulge. After the war, he used his GI Bill money to study at the Sorbonne where he received a Ph.D. for the thesis Un essai sur l'expérience poétique (étude introspective) in 1950.
In the 1950s, Menashe returned to New York where, except for frequent sojourns in England and Ireland, he lived most of his life. In 1961, he garnered the blessing of the British poet Kathleen Raine who arranged for his first book, The Many Named Beloved, to be published by Victor Gollancz in London. Menashe's short, intense, spiritual poems, which canvass existential dilemmas and use implication and wordplay as a way of deepening the linguistic force of his words, gained wide renown in Britain from reviewers such as Donald Davie, who became one of Menashe's most committed backers. He was later included in the Penguin Modern Poets series.
In 2004 he became the first poet honored with the "Neglected Masters Award" given by Poetry magazine and the Poetry Foundation. The award was also to include a book to be published by the Library of America, which turned out to be a "Selected Poems" edited
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https://en.wikipedia.org/wiki/Marcel%20Otte
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Marcel Otte (born 5 October 1948) is a professor of Prehistory at the Université de Liège, Belgium. He is a specialist in Religion, Arts, Sociobiology, and the Upper Palaeolithic times of Europe and Central Asia. In the book Speaking Australopithecus (written together with the philologist Francesco Benozzo) he argues from the archaeological point of view Benozzo's hypothesis that human language appeared with Australopithecus, between 4 and 3 million years ago.
Otte is one of the only advocates of the Paleolithic continuity theory, which states that Indo-European languages originated in Europe and have existed there since Paleolithic times. He first advocated that theory in work published in 1995.
Written works
He has published a number of works, including:
Étude Archéologique et Historique sur le Château Médièval de Saive Centre belge d'histoire rurale Liege 1973
Les Pointes à Retouches Plates du Paléolithique Supérieur Initial de Belgique Centre Interdisciplinaire de Recherches Archéologiques Liege 1974
La préhistoire à Travers les Collections du Musée Curtius de Liège Wahle Liege 1978
Le Paléolithique Supérieur Ancien en Belgique Musées Royaux d'art et d'histoire Brussels 1979
Le Gravettien en Europe Centrale De Tempel Brugge 1981
Sondages à Marche-les-Dames : Grotte de la Princesse, 1976 with J.M. Degbomont, University of Liege 1981
Les Fouilles de la place Saint-Lambert à Liège Le Centre Liège 1983
Préhistoire des Religions Masson Paris 1993 2-225-84068-7
Le P
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https://en.wikipedia.org/wiki/Mohr%27s%20circle
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Mohr's circle is a two-dimensional graphical representation of the transformation law for the Cauchy stress tensor.
Mohr's circle is often used in calculations relating to mechanical engineering for materials' strength, geotechnical engineering for strength of soils, and structural engineering for strength of built structures. It is also used for calculating stresses in many planes by reducing them to vertical and horizontal components. These are called principal planes in which principal stresses are calculated; Mohr's circle can also be used to find the principal planes and the principal stresses in a graphical representation, and is one of the easiest ways to do so.
After performing a stress analysis on a material body assumed as a continuum, the components of the Cauchy stress tensor at a particular material point are known with respect to a coordinate system. The Mohr circle is then used to determine graphically the stress components acting on a rotated coordinate system, i.e., acting on a differently oriented plane passing through that point.
The abscissa and ordinate (,) of each point on the circle are the magnitudes of the normal stress and shear stress components, respectively, acting on the rotated coordinate system. In other words, the circle is the locus of points that represent the state of stress on individual planes at all their orientations, where the axes represent the principal axes of the stress element.
19th-century German engineer Karl Culmann was t
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https://en.wikipedia.org/wiki/Array%20processing
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Array processing is a wide area of research in the field of signal processing that extends from the simplest form of 1 dimensional line arrays to 2 and 3 dimensional array geometries. Array structure can be defined as a set of sensors that are spatially separated, e.g. radio antenna and seismic arrays. The sensors used for a specific problem may vary widely, for example microphones, accelerometers and telescopes. However, many similarities exist, the most fundamental of which may be an assumption of wave propagation. Wave propagation means there is a systemic relationship between the signal received on spatially separated sensors. By creating a physical model of the wave propagation, or in machine learning applications a training data set, the relationships between the signals received on spatially separated sensors can be leveraged for many applications.
Some common problem that are solved with array processing techniques are:
determine number and locations of energy-radiating sources
enhance the signal to noise ratio SNR "signal-to-interference-plus-noise ratio (SINR)"
track moving sources
Array processing metrics are often assessed noisy environments. The model for noise may be either one of spatially incoherent noise, or one with interfering signals following the same propagation physics. Estimation theory is an important and basic part of signal processing field, which used to deal with estimation problem in which the values of several parameters of the system sho
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https://en.wikipedia.org/wiki/Beamforming
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Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity. The improvement compared with omnidirectional reception/transmission is known as the directivity of the array.
Beamforming can be used for radio or sound waves. It has found numerous applications in radar, sonar, seismology, wireless communications, radio astronomy, acoustics and biomedicine. Adaptive beamforming is used to detect and estimate the signal of interest at the output of a sensor array by means of optimal (e.g. least-squares) spatial filtering and interference rejection.
Techniques
To change the directionality of the array when transmitting, a beamformer controls the phase and relative amplitude of the signal at each transmitter, in order to create a pattern of constructive and destructive interference in the wavefront. When receiving, information from different sensors is combined in a way where the expected pattern of radiation is preferentially observed.
For example, in sonar, to send a sharp pulse of underwater sound towards a ship in the distance, simply simultaneously transmitting that sharp pulse from every sonar projecto
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https://en.wikipedia.org/wiki/Quantum%20wire
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In mesoscopic physics, a quantum wire is an electrically conducting wire in which quantum effects influence the transport properties. Usually such effects appear in the dimension of nanometers, so they are also referred to as nanowires.
Quantum effects
If the diameter of a wire is sufficiently small, electrons will experience quantum confinement in the transverse direction. As a result, their transverse energy will be limited to a series of discrete values. One consequence of this quantization is that the classical formula for calculating the electrical resistance of a wire,
is not valid for quantum wires (where is the material's resistivity, is the length, and is the cross-sectional area of the wire).
Instead, an exact calculation of the transverse energies of the confined electrons has to be performed to calculate a wire's resistance. Following from the quantization of electron energy, the electrical conductance (the inverse of the resistance) is found to be quantized in multiples of , where is the electron charge and is the Planck constant. The factor of two arises from spin degeneracy. A single ballistic quantum channel (i.e. with no internal scattering) has a conductance equal to this quantum of conductance. The conductance is lower than this value in the presence of internal scattering.
The importance of the quantization is inversely proportional to the diameter of the nanowire for a given material. From material to material, it is dependent on the electronic
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https://en.wikipedia.org/wiki/Rindler%20coordinates
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Rindler coordinates are a coordinate system used in the context of special relativity to describe the hyperbolic acceleration of a uniformly accelerating reference frame in flat spacetime. In relativistic physics the coordinates of a hyperbolically accelerated reference frame constitute an important and useful coordinate chart representing part of flat Minkowski spacetime. In special relativity, a uniformly accelerating particle undergoes hyperbolic motion, for which a uniformly accelerating frame of reference in which it is at rest can be chosen as its proper reference frame. The phenomena in this hyperbolically accelerated frame can be compared to effects arising in a homogeneous gravitational field. For general overview of accelerations in flat spacetime, see Acceleration (special relativity) and Proper reference frame (flat spacetime).
In this article, the speed of light is defined by , the inertial coordinates are , and the hyperbolic coordinates are . These hyperbolic coordinates can be separated into two main variants depending on the accelerated observer's position: If the observer is located at time at position (with as the constant proper acceleration measured by a comoving accelerometer), then the hyperbolic coordinates are often called Rindler coordinates with the corresponding Rindler metric. If the observer is located at time at position , then the hyperbolic coordinates are sometimes called Møller coordinates or Kottler–Møller coordinates with the corresp
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https://en.wikipedia.org/wiki/Yves%20Balasko
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Yves Balasko is a French economist working in England. He was born in Paris on 9 August 1945 to a Hungarian father and a French mother. After studying mathematics at the École Normale Supérieure in Paris he became interested in economics. He subsequently spent six years at Électricité de France where he was involved in the application of the theory of marginal cost pricing to electricity pricing. While at Électricité de France, he proved his first results on the structure of the equilibrium manifold in the theory of general equilibrium. After completing his dissertation on "L'équilibre économique du point de vue differentiel" (English: "The Economic equilibrium from the differential point of view"), he had positions at the Universities of Paris XII, Paris I, Geneva and York. In 2013, he held a visiting scholar position at Pontifical Catholic University of Rio de Janeiro, in Brazil. Since 2014, he has returned to York University.
He is a Fellow of the Econometric Society since 1980. He is also a Vice President of the Society for Economic Measurement (SEM).
In mathematical economics, Balasko has worked on general equilibrium theory, the overlapping generations model and the theory of incomplete asset markets. In his research, Balasko uses topology.
Books
Foundations of the Theory of General Equilibrium, 1988, .
The Equilibrium Manifold: Postmodern Developments in the Theory of General Economic Equilibrium, 2009,
General Equilibrium Theory of Value, 2011,
External links
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https://en.wikipedia.org/wiki/Hugo%20Dingler
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Hugo Albert Emil Hermann Dingler (July 7, 1881, Munich – June 29, 1954, Munich) was a German scientist and philosopher.
Life
Hugo Dingler studied mathematics, philosophy, and physics with Felix Klein, Hermann Minkowski, David Hilbert, Edmund Husserl, Woldemar Voigt, and Wilhem Roentgen at the universities of Göttingen and Munich. He graduated from the University of Munich with a thesis under Aurel Voss. Dingler earned his Ph.D. in mathematics, physics and astronomy in 1906. His doctoral advisor was Ferdinand von Lindemann. In 1910 Dingler's first attempt to earn a Habilitation failed. His second try in 1912 was successful. Dingler then taught as a Privatdozent and hold lectures on mathematics, philosophy and the history of science. He became a professor at the University of Munich in 1920. Dingler got a position as Professor ordinarius in Darmstadt in 1932.
In 1934, one year after the Nazis took power Dingler was dismissed from his teaching position for still unclear reasons. Dingler himself told several interviewers that this was because of his favorable writings concerning Jews. In fact both philo-semitic as well as anti-semitic statements by Dingler had been noted.
From 1934 to 1936 he again held a teaching position.
In 1940 Dingler joined the Nazi Party and was again given a teaching position. Of Dingler's 1944 book Aufbau der exakten Fundamentalwissenschaft only thirty copies survived wartime bombing.
Thought
Dingler's position is usually characterized as "conventio
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https://en.wikipedia.org/wiki/Jean%20Charles%20Athanase%20Peltier
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Jean Charles Athanase Peltier (; ; 22 February 1785 – 27 October 1845) was a French physicist. He was originally a watch dealer, but at the age of 30 began experiments and observations in physics.
Peltier was the author of numerous papers in different departments of physics. His name is specially associated with the thermal effects at junctions in a voltaic circuit, the Peltier effect. Peltier introduced the concept of electrostatic induction (1840), based on the modification of the distribution of electric charge in a material under the influence of a second object closest to it and its own electrical charge.
Biography
Peltier trained as a watchmaker; until his 30s was a watch dealer. Peltier worked with Abraham Louis Breguet in Paris. Later, he worked with various experiments on electrodynamics and noticed that in an electronic element when current flows through, a temperature gradient or temperature difference is generated at a current flow. In 1836 he published his work and in 1838 his findings were confirmed by Emil Lenz. Peltier dealt with topics from the atmospheric electricity and meteorology. In 1840, he published a work on the causes of hurricanes.
Peltier's numerous papers are devoted in great part to atmospheric electricity, waterspouts, cyanometry and polarization of sky-light, the temperature of water in the spheroidal state, and the boiling-point at high elevations. There are also a few devoted to curious points of natural history. His name will always be a
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https://en.wikipedia.org/wiki/Chiral%20model
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In nuclear physics, the chiral model, introduced by Feza Gürsey in 1960, is a phenomenological model describing effective interactions of mesons in the chiral limit (where the masses of the quarks go to zero), but without necessarily mentioning quarks at all. It is a nonlinear sigma model with the principal homogeneous space of a Lie group as its target manifold. When the model was originally introduced, this Lie group was the SU(N) , where N is the number of quark flavors. The Riemannian metric of the target manifold is given by a positive constant multiplied by the Killing form acting upon the Maurer–Cartan form of SU(N).
The internal global symmetry of this model is , the left and right copies, respectively; where the left copy acts as the left action upon the target space, and the right copy acts as the right action. Phenomenologically, the left copy represents flavor rotations among the left-handed quarks, while the right copy describes rotations among the right-handed quarks, while these, L and R, are completely independent of each other. The axial pieces of these symmetries are spontaneously broken so that the corresponding scalar fields are the requisite Nambu−Goldstone bosons.
The model was later studied in the two-dimensional case as an integrable system, in particular an integrable field theory. Its integrability was shown by Faddeev and Reshetikhin in 1982 through the quantum inverse scattering method. The two-dimensional principal chiral model exhibits signat
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https://en.wikipedia.org/wiki/Friedrich%20Sert%C3%BCrner
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Friedrich Wilhelm Adam Sertürner (19 June 1783 – 20 February 1841) was a German pharmacist and a pioneer of alkaloid chemistry. He is best known for his discovery of morphine in 1804.
Biography
Friedrich Wilhelm Adam Sertürner was born to Joseph Simon Serdinner and Marie Therese Brockmann on 19 June 1783, in Neuhaus, North Rhine-Westphalia (now part of Paderborn). After his parents died, he became a pharmacist's apprentice in Paderborn.
Sertürner was the first to isolate morphine from opium. He called the isolated alkaloid "morphium" after the Greek god of dreams, Morpheus. He published a comprehensive paper on its isolation, crystallization, crystal structure, and pharmacological properties, which he studied first in stray dogs and then in self-experiments. Morphine was not only the first alkaloid to be extracted from opium, but the first ever alkaloid to be isolated from any plant. Thus Sertürner became the first person to isolate the active ingredient associated with a medicinal plant or herb.
The branch of science that he originated has since become known as alkaloid chemistry.
In 1806 Sertürner moved to Einbeck, working as a pharmacists' assistant. In 1809, Sertürner opened the first pharmacy he owned, in Einbeck. He continued to investigate the effects of morphine. After the publication of his paper "Ueber das Morphium als Hauptbestandteil des Opiums" in 1817, his work on morphine became more widely known and morphine became more widely used.
In 1822, Sertürner
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https://en.wikipedia.org/wiki/Tobias%20Mayer
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Tobias Mayer (17 February 172320 February 1762) was a German astronomer famous for his studies of the Moon.
He was born at Marbach, in Württemberg, and brought up at Esslingen in poor circumstances. A self-taught mathematician, he earned a living by teaching mathematics while still a youth. He had already published two original geometrical works when, in 1746, he entered J. B. Homann's cartographic establishment at Nuremberg. Here he introduced many improvements in mapmaking, and gained a scientific reputation which led (in 1751) to his election to the chair of economy and mathematics at the University of Göttingen. In 1754 he became superintendent of the observatory, where he worked until his death in 1762.
Career
Mayer's first important astronomical work was a careful investigation of the libration of the Moon (Kosmographische Nachrichten, Nuremberg, 1750), and his chart of the full moon (published in 1775) was unsurpassed for half a century. But his fame rests chiefly on his lunar tables, communicated in 1752, with new solar tables to the Königliche Gesellschaft der Wissenschaften zu Göttingen (Royal Society of Sciences at Göttingen), and published in their transactions. In 1755 he submitted to the British government an amended body of manuscript tables, which James Bradley compared with the Greenwich observations. He found these to be sufficiently accurate to determine the Moon's position to 75", and consequently the longitude at sea to about half a degree. An improved
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https://en.wikipedia.org/wiki/Johann%20Tobias%20Mayer
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Johann Tobias Mayer (5 May 1752 – 30 November 1830) was a German physicist.
Personal and professional life
Mayer, born in Göttingen, was the first child of the astronomer Tobias Mayer and his wife Maria. The elder Mayer, a well-known Göttingen professor of geography, physics, and astronomy, died in 1762, when Johann was only ten.
Johann Tobias Mayer studied theology and philosophy since 1769 at the Georg-August University of Göttingen (founded 1737) under Abraham Gotthelf Kästner and later also with Georg Christoph Lichtenberg. After graduating in 1773, Mayer worked as a lecturer in mathematics and as an astronomer. On 17 November 1779, he was called to the University of Altdorf, where he worked from 1780 to 1786. He later taught mathematics and physics at Friedrich-Alexander-University, Erlangen-Nuremberg, and in 1799, he succeeded Lichtenberg at Göttingen. The mathematician Enno Dirksen was one of his doctoral students.
Mayer was well known for his mathematics and natural science textbooks. The textbook Anfangsgründe der Naturlehre zum Behuf der Vorlesungen über die Experimental-Physik from 1801 was the most influential of its time in the German-speaking countries. Mayer's research in experimental physics and astronomy was published in Annalen der Physik.
Mayer and his wife Johanna had five children. Mayer died in Göttingen.
The Leonardo da Vinci Proof of the Pythagorean Theorem
A proof of the Pythagorean theorem ascribed to Leonardo da Vinci is now claimed to
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https://en.wikipedia.org/wiki/Keith%20Geddes
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Keith Oliver Geddes (born 1947) is a professor emeritus in the David R. Cheriton School of Computer Science within the Faculty of Mathematics at the University of Waterloo in Waterloo, Ontario. He is a former director of the Symbolic Computation Group in the School of Computer Science. He received a BA in Mathematics at the University of Saskatchewan in 1968; he completed both his MSc and PhD in Computer Science at the University of Toronto.
Geddes is probably best known for co-founding the Maple computer algebra system, now in widespread academic use around the world. He is also the Scientific Director at the Ontario Research Centre for Computer Algebra, and is a member of the Association for Computing Machinery, as well as the American and Canadian Mathematical Societies.
Research
Geddes' primary research interest is to develop algorithms for the mechanization of mathematics. More specifically, he is interested in the computational aspects of algebra and analysis. Currently, he is focusing on designing hybrid symbolic-numeric algorithms to perform definite integration and solve ordinary and partial differential equations.
Much of his work currently revolves around Maple.
Teaching
Geddes retired from teaching in December 2008.
Geddes taught a mixture of both senior-level symbolic computation courses, at both the undergraduate and graduate level, as well as introductory courses on the principles of computer science.
See also
Maple computer algebra system
Waterl
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https://en.wikipedia.org/wiki/Francis%20Barrett%20%28occultist%29
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Francis Barrett (born probably in London around 1770–1780, died after 1802) was an English occultist.
Background
Barrett, an Englishman, claimed himself to be a student of chemistry, metaphysics and natural occult philosophy. He was known to be an extreme eccentric who gave lessons in the magical arts in his apartment and fastidiously translated Kabbalistic and other ancient texts into English, such as von Welling's work, Philosophy of The Universe circa 1735, from German (1801). According to his biographer Francis X. King, Barrett's parents were humble folk married in the parish of St. Martin's in the Fields on 29 September 1772.
The Magus
Barrett was enthusiastic about reviving interest in the occult arts, and published a magical textbook called The Magus. It was a compilation, almost entirely consisting of selections from Cornelius Agrippa's Three Books of Occult Philosophy, the Fourth Book of Occult Philosophy attributed to Agrippa, and Robert Turner's 1655 translation of the Heptameron of Peter of Abano. Barrett made modifications and modernized spelling and syntax.
The Magus dealt with the natural magic of herbs and stones, magnetism, talismanic magic, alchemy, numerology, the elements, and biographies of famous adepts from history.
The Magus also served as an advertising tool. In it Barrett sought interested people wanting to help form his magic circle. An advertisement in The Magus (Vol. 2, p. 140) refers to an otherwise unknown school founded by Barrett.
Accord
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https://en.wikipedia.org/wiki/Effector
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Effector may refer to:
Effector (biology), a molecule that binds to a protein and thereby alters the activity of that protein
Effector (album), a music album by the Experimental Techno group Download
EFFector, a publication of the Electronic Frontier Foundation
See also
Effexor, a brand name for the antidepressant venlafaxine
Bacterial effector protein, proteins secreted by bacterial pathogens into the cells of their host
Effector cell
End effector, the device at the end of a robotic arm
Affect (disambiguation)
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https://en.wikipedia.org/wiki/Document%20classification
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Document classification or document categorization is a problem in library science, information science and computer science. The task is to assign a document to one or more classes or categories. This may be done "manually" (or "intellectually") or algorithmically. The intellectual classification of documents has mostly been the province of library science, while the algorithmic classification of documents is mainly in information science and computer science. The problems are overlapping, however, and there is therefore interdisciplinary research on document classification.
The documents to be classified may be texts, images, music, etc. Each kind of document possesses its special classification problems. When not otherwise specified, text classification is implied.
Documents may be classified according to their subjects or according to other attributes (such as document type, author, printing year etc.). In the rest of this article only subject classification is considered. There are two main philosophies of subject classification of documents: the content-based approach and the request-based approach.
"Content-based" versus "request-based" classification
Content-based classification is classification in which the weight given to particular subjects in a document determines the class to which the document is assigned. It is, for example, a common rule for classification in libraries, that at least 20% of the content of a book should be about the class to which the book
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https://en.wikipedia.org/wiki/B%20%E2%88%92%20L
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In particle physics, B − L (pronounced "bee minus ell") is a quantum number which is the difference between the baryon number () and the lepton number () of a quantum system.
Details
This quantum number is the charge of a global/gauge U(1) symmetry in some Grand Unified Theory models, called . Unlike baryon number alone or lepton number alone, this hypothetical symmetry would not be broken by chiral anomalies or gravitational anomalies, as long as this symmetry is global, which is why this symmetry is often invoked.
If exists as a symmetry, then for the seesaw mechanism to work has to be spontaneously broken to give the neutrinos a nonzero mass.
The anomalies that would break baryon number conservation and lepton number conservation individually cancel in such a way that is always conserved. One hypothetical example is proton decay where a proton () would decay into a pion () and positron ().
The weak hypercharge is related to via
where X charge (not to be confused with the X boson) is the conserved quantum number associated with the global U(1) symmetry Grand Unified Theory.
See also
Baryogenesis
Leptogenesis
Majoron
Proton decay
X and Y bosons
X (charge)
Leptoquark
References
Conservation laws
Flavour (particle physics)
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https://en.wikipedia.org/wiki/Lepton%20number
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In particle physics, lepton number (historically also called lepton charge)
is a conserved quantum number representing the difference between the number of leptons and the number of antileptons in an elementary particle reaction.
Lepton number is an additive quantum number, so its sum is preserved in interactions (as opposed to multiplicative quantum numbers such as parity, where the product is preserved instead). The lepton number is defined by
where
is the number of leptons and
is the number of antileptons.
Lepton number was introduced in 1953 to explain the absence of reactions such as
in the Cowan–Reines neutrino experiment, which instead observed
.
This process, inverse beta decay, conserves lepton number, as the incoming antineutrino has lepton number −1, while the outgoing positron (antielectron) also has lepton number −1.
Lepton flavor conservation
In addition to lepton number, lepton family numbers are defined as
the electron number, for the electron and the electron neutrino;
the muon number, for the muon and the muon neutrino; and
the tau number, for the tauon and the tau neutrino.
Prominent examples of lepton flavor conservation are the muon decays
and
.
In these decay reactions, the creation of an electron is accompanied by the creation of an electron antineutrino, and the creation of a positron is accompanied by the creation of an electron neutrino. Likewise, a decaying negative muon results in the creation of a muon neutrino, while a decay
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https://en.wikipedia.org/wiki/Vassilis%20Papazachos
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Vassilis Papazachos (; 30 September 1929 – 10 November 2022) was a Greek seismologist and author of Earthquakes of Greece.
Born on 30 September 1929 in the village of Smokovo in Karditsa regional unit, Vassilis Papazachos studied physics in the University of Athens, Greece. He received a M.Sc. in geophysics from Saint Louis University (1963) and a doctorate in Seismology from the University of Athens (1961). He first became involved in geophysics as an assistant of professor Angelos Galanopoulos (1955–1956) and then moved to the Geodynamic Institute of the National Observatory of Athens (1956–1977). Later in his career he became Professor of Seismology in the Aristotle University (1977–1998), where he was still active as an emeritus professor.
Papazachos always attracted publicity in his country Greece, which is highly seismogenic and has been tormented by many earthquakes both in historic and prehistoric times. He was an ardent opposer of Panayotis Varotsos and the VAN method for earthquake prediction, which he called "the greatest science joke of the century".
Vassilis Papazachos was also involved in Greek politics for long time. A supporter of the left, he was asked by the Communist Party of Greece to lead their ticket and run for mayor of Thessaloniki, but he refused, saying that such active involvement would distract him from his scientific work. However, he eventually ran for mayor in his birthplace with the support of the Synaspismos party of the radical left. He wa
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https://en.wikipedia.org/wiki/Betsy%20Devine
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Betsy Devine (born 1946) is an American author, journalist, and blogger, with published works including Longing for the Harmonies (1988), an appreciation of modern physics with Nobel laureate Frank Wilczek, and of Absolute Zero Gravity (1993), a collection of light-hearted material about science, with biologist Joel E. Cohen. She is a Wikipedian and spoke at Wikimania in 2006.
Biography
Devine earned a master's degree in engineering from Princeton University.
Devine has had, according to her self-description, "many years of immersion in geek sociology, including both Slashdot and Wikipedia flame wars". She is co-author, with husband Frank Wilczek, of Longing for the Harmonies, an appreciation of modern physics; and also, with biologist Joel E. Cohen, of Absolute Zero Gravity, a collection of science jokes, poems, and stories. About 75 pages taken from her blog were included as "a contribution" to a collection of essays written by Frank Wilczek on various aspects of physics, Fantastic Realities.
Devine spoke at Wikimania in 2006.
Selected works
References
External links
Now with Even More Funny Ha-Ha and Peculiar—Betsy's blog
2003 interview with Frank Paynter
2004 interview with Steve Rubel about her work for Feedster
"Blogging in Boston" podcast with Tony Kahn, from "Morning Stories" show aired in 2004 (Link is to mp3 file)
2005 Podcast conversation with Dave Winer (Link is to mp3 file of 40-minute conversation)
1946 births
Living people
American bloggers
20th-ce
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https://en.wikipedia.org/wiki/Panayiotis%20Varotsos
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Panayiotis Varotsos (; born November 28, 1947 in Patras) is a Greek physicist and former professor in the Department of Physics of the University of Athens, notable for his VAN method to predict earthquakes.
His group claims the ability to identify electromagnetic signals that are precursors to earthquakes. They suggest the precursors are generated by electricity from piezo-stimulated effects in rocks being stressed just prior to the earthquake rupture. Onassis Foundation Laureate for the Environment (1995). Also awarded by the Academy of Athens (1978) and Empeirikion Foundation (1986). In 2016 the Union of Greek Physicists honoured him for his work with a prize delivered by the President of Greece.
Works
References
Further reading
Physics Web, Maxwell Equations and Earthquakes, News from VAN Research Group, May 2004 (in Greek). Retrieved on 07-08-2016 from Physics4u.
New Scientist Environment, Heartbeats warn of sudden death risk, March 31, 2004. Retrieved on 07-08-2016 from New Scientist.
S.N. Kodellas, Research University Institutes, July 1, 2005 (in Greek). 2007-06-02.
Panayiotis Varotsos, Curriculum Vitae and Publication List, 19-02-2015 (in Greek). Retrieved on 07-08-2016.
Greek seismologists
21st-century Greek physicists
Academic staff of the National and Kapodistrian University of Athens
1947 births
Living people
20th-century Greek physicists
People from Patras
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https://en.wikipedia.org/wiki/T-tree
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In computer science a T-tree is a type of binary tree data structure that is used by main-memory databases, such as Datablitz, eXtremeDB, MySQL Cluster, Oracle TimesTen and MobileLite.
A T-tree is a balanced index tree data structure optimized for cases
where both the index and the actual data are fully kept in memory, just as a B-tree is an index structure optimized for storage on block oriented secondary storage devices like hard disks. T-trees seek to gain the performance benefits of in-memory tree structures such as AVL trees while avoiding the large storage space overhead which is common to them.
T-trees do not keep copies of the indexed data fields within the index tree nodes themselves. Instead, they take advantage of the fact that the actual data is always in main memory together with the index so that they just contain pointers to the actual data fields.
The 'T' in T-tree refers to the shape of the node data structures in the original paper which first described this type of index.
Node structures
A T-tree node usually consists of pointers to the parent node, the left and right child node, an ordered array of data pointers and some extra control data. Nodes with two subtrees are called internal nodes, nodes without subtrees are called leaf nodes and nodes with only one subtree are named half-leaf nodes. A node is called the bounding node for a value if the value is between the node's current minimum and maximum value, inclusively.
For each internal node, leaf o
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https://en.wikipedia.org/wiki/Open%20problem
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In science and mathematics, an open problem or an open question is a known problem which can be accurately stated, and which is assumed to have an objective and verifiable solution, but which has not yet been solved (i.e., no solution for it is known).
In the history of science, some of these supposed open problems were "solved" by means of showing that they were not well-defined.
In mathematics, many open problems are concerned with the question of whether a certain definition is or is not consistent.
Two notable examples in mathematics that have been solved and closed by researchers in the late twentieth century are Fermat's Last Theorem and the four-color theorem. An important open mathematics problem solved in the early 21st century is the Poincaré conjecture.
Open problems exist in all scientific fields.
For example, one of the most important open problems in biochemistry is the protein structure prediction problem – how to predict a protein's structure from its sequence.
See also
Lists of unsolved problems (by major field)
Hilbert's problems
Millennium Prize Problems
References
External links
Open Problem Garden The collection of open problems in mathematics build on the principle of user editable ("wiki") site
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https://en.wikipedia.org/wiki/Teas
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Teas or TEAS can mean:
Tea, a traditional beverage made from steeping the processed leaves, buds, or twigs of the tea bush (Camellia sinensis) in water.
Test of Essential Academic Skills, a standardized aptitude test used for entrance to nursing schools
Thermal energy atom scattering, a physics technique, see Helium atom scattering
Trademark Electronic Application System at United States Patent and Trademark Office
The Eric Andre Show, an Adult Swim television series
The European Azerbaijan Society
Trans European Asia System, a planned submarine communications cable
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https://en.wikipedia.org/wiki/Scientific%20Computing%20%26%20Instrumentation
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Scientific Computing (SC) (formerly Scientific Computing & Instrumentation - SC&I) is a trade publication of Advantage Business Media. It focuses on the scientific applications of computers for automating laboratory and instrument operations. While all aspects of scientific automation are covered, special emphasis is given to the areas of laboratory information management systems (LIMS), laboratory information systems (LIS), chromatography data systems (CDS), and Scientific data management systems (SDMS). It is published monthly, and currently has a global circulation of ~70k, mostly scientific and technical professionals. Subscriptions are free to qualified recipients (those working in the field).
The feature making this publication most useful to those working in the field is its annual supplements, many of which contain detailed vendor responses regarding their systems design. All of these questionnaires are posted on the publication's Web site, along with all articles, focus columns, and vendor submissions. It also provides a focus for vendor advertising, so that those looking to acquire one of these systems will have a starting point for research.
SC has recently started hosting online technical seminars, Web conferences, and expositions.
References
External links
Official website
WorldCat record
Computer science journals
Publications with year of establishment missing
Laboratory information management system
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https://en.wikipedia.org/wiki/Tiedemann%20Giese
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Tiedemann Giese (1 June 1480 – 23 October 1550), was Bishop of Kulm (Chełmno) first canon, later Prince-Bishop of Warmia (Ermland)wwhose hose interest in mathematics, astronomy, and theology led him to mentor a number of important young scholars, including Copernicus. He was a prolific writer and correspondent, publishing a number of works on the reformation of the church. Tiedemann was a member of the patrician Giese family of Danzig (Gdańsk) in Poland. The Giese family ancestors originated from Unna in Westphalia, near Dortmund. His father was Albrecht Giese and his younger brother, the Hanseatic League merchant Georg Giese.
Life and career
Giese was the fifth child of Albrecht Giese and his wife, Elisabeth Langenbeck, both members of wealthy merchant families. His paternal family had emigrated from Cologne to Danzig in the 1430s. His father was the Mayor of Danzig, and his mother's uncle, Johann Ferber, had been Mayor of Danzig.
At the age of 12 years, Tiedemann, along with his cousin, Johann Ferber, entered the University of Leipzig, and subsequently studied at Basel and in Italy. He earned a Master of Theology degree. Giese was one of the best educated scholars in Prussia, well versed in both theology and the sciences. At age 24, he and Mauritius Ferber (possibly a cousin) became priests at the Catholic Church of St. Peter and St. Paul.
He was secretary to the King of Poland, and later appointed canon of Frauenburg (Frombork), where he remained for 30 years. His resi
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https://en.wikipedia.org/wiki/Wei%20Yen
|
Wei Yen () is a Taiwanese-American technologist and serial entrepreneur. He has been involved with several companies, including most recently as Chairman and Founder of AiLive.
Yen received his Ph.D. in Electrical Engineering in Operating Systems and Artificial Intelligence from Purdue University. Yen and his brother David Yen along with King-sun Fu published the paper "Data Coherence Problem in a Multicache System" that describes a practical cache coherence protocol.
Career
Yen served as the Director of Software Engineering for Cydrome, where he worked with his brother David, who served as the Director of Hardware Engineering. They were the major contributors to the Cydra-5 mini-supercomputer. The system was a combination of a VLIW ECL-based processor used for scientific applications and a multi-processor system designed for a bus architecture based on their Cache Coherence protocol.
Yen served as Senior Vice President of Silicon Graphics from 1988 to 1996, where he led development on OpenGL and also served as President of subsidiary MIPS Technologies. In 1996, he left SGI and founded TVsoft, a maker of interactive software for television setup devices. The company was renamed Navio and later merged with Oracle's Network Computer. Subsequently, the company went public as Liberate Technologies in July 1999. Its public offering reached a $12 billion valuation in early 2000 with a revenue run rate of $25 million.
In parallel, Yen founded a company called ArtX, employed with
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https://en.wikipedia.org/wiki/Cartan%20subalgebra
|
In mathematics, a Cartan subalgebra, often abbreviated as CSA, is a nilpotent subalgebra of a Lie algebra that is self-normalising (if for all , then ). They were introduced by Élie Cartan in his doctoral thesis. It controls the representation theory of a semi-simple Lie algebra over a field of characteristic .
In a finite-dimensional semisimple Lie algebra over an algebraically closed field of characteristic zero (e.g., a Cartan subalgebra is the same thing as a maximal abelian subalgebra consisting of elements x such that the adjoint endomorphism is semisimple (i.e., diagonalizable). Sometimes this characterization is simply taken as the definition of a Cartan subalgebra.pg 231
In general, a subalgebra is called toral if it consists of semisimple elements. Over an algebraically closed field, a toral subalgebra is automatically abelian. Thus, over an algebraically closed field of characteristic zero, a Cartan subalgebra can also be defined as a maximal toral subalgebra.
Kac–Moody algebras and generalized Kac–Moody algebras also have subalgebras that play the same role as the Cartan subalgebras of semisimple Lie algebras (over a field of characteristic zero).
Existence and uniqueness
Cartan subalgebras exist for finite-dimensional Lie algebras whenever the base field is infinite. One way to construct a Cartan subalgebra is by means of a regular element. Over a finite field, the question of the existence is still open.
For a finite-dimensional semisimple Lie alge
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https://en.wikipedia.org/wiki/Loop%20algebra
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In mathematics, loop algebras are certain types of Lie algebras, of particular interest in theoretical physics.
Definition
For a Lie algebra over a field , if is the space of Laurent polynomials, then
with the inherited bracket
Geometric definition
If is a Lie algebra, the tensor product of with , the algebra of (complex) smooth functions over the circle manifold (equivalently, smooth complex-valued periodic functions of a given period),
is an infinite-dimensional Lie algebra with the Lie bracket given by
Here and are elements of and and are elements of .
This isn't precisely what would correspond to the direct product of infinitely many copies of , one for each point in , because of the smoothness restriction. Instead, it can be thought of in terms of smooth map from to ; a smooth parametrized loop in , in other words. This is why it is called the loop algebra.
Gradation
Defining to be the linear subspace the bracket restricts to a product
hence giving the loop algebra a -graded Lie algebra structure.
In particular, the bracket restricts to the 'zero-mode' subalgebra .
Derivation
There is a natural derivation on the loop algebra, conventionally denoted acting as
and so can be thought of formally as .
It is required to define affine Lie algebras, which are used in physics, particularly conformal field theory.
Loop group
Similarly, a set of all smooth maps from to a Lie group forms an infinite-dimensional Lie group (Lie group in the sense we c
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https://en.wikipedia.org/wiki/Ernst%20Mohr
|
Ernst Mohr was a professor of mechanical engineering at the University of Wuppertal. He developed the meteorological Mohr Rocket, on behalf of the German Rocket Society. The rocket was first launched successfully on September 14, 1958 near Cuxhaven.
At the first successful test the rocket reached heights of 50 kilometers and could send out its payload at speeds of 1.2 km per second.
External links
Encyclopedia Astronautica
German mechanical engineers
Academic staff of the University of Wuppertal
Engineers from North Rhine-Westphalia
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https://en.wikipedia.org/wiki/Hatch
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Hatch or The Hatch may refer to:
Common meanings
Biology
Hatch, to emerge from an egg
Hatch(ing), the process of egg incubation
Portals
Hatch, a sealed or secure door of a ship, submarine, aircraft, spacecraft, or automobile
Hatch, a sluice gate
Hatch, a trapdoor, a door on a floor or ceiling
Places
Antarctica
Hatch Islands, Wilkes Land, Antarctica
Hatch Plain, Coats Land, Antarctica
Australia
The Hatch, New South Wales, a suburb within Port Macquarie-Hastings Council
England
Hatch, Bedfordshire, a hamlet
Hatch Beauchamp, Somerset
Hatch Park, a Site of Special Scientific Interest in Kent
East Hatch and West Hatch, hamlets within the parish of West Tisbury, Wiltshire
West Hatch, hamlet and civil parish in Somerset
United States
Hatch, Idaho, an unincorporated community
Hatch, Missouri, an unincorporated community
Hatch, New Mexico, a village
Hatch, Utah, a town
Hatch Airport, an airport in Stayton, Oregon
People with the name
Hatch (surname)
Harrison Hatch Rosdahl (1941–2004), American football player
Arts, entertainment, and media
Hatch, a bug-like villain from the TV show Hot Wheels Battle Force 5
The Hatch, the third DHARMA Initiative station in the television show Lost
Other uses
Hatch chile, sub-cultivars of the New Mexico chile pepper cultivar group grown near Hatch, New Mexico
Hatch (e-commerce company), an ecommerce platform based in Amsterdam
Hatch Ltd, an engineering and development consulting company based in Canada
Hatch-class lifeboat, formerly operated
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https://en.wikipedia.org/wiki/Topological%20property
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In topology and related areas of mathematics, a topological property or topological invariant is a property of a topological space that is invariant under homeomorphisms. Alternatively, a topological property is a proper class of topological spaces which is closed under homeomorphisms. That is, a property of spaces is a topological property if whenever a space X possesses that property every space homeomorphic to X possesses that property. Informally, a topological property is a property of the space that can be expressed using open sets.
A common problem in topology is to decide whether two topological spaces are homeomorphic or not. To prove that two spaces are not homeomorphic, it is sufficient to find a topological property which is not shared by them.
Properties of topological properties
A property is:
Hereditary, if for every topological space and subset the subspace has property
Weakly hereditary, if for every topological space and closed subset the subspace has property
Common topological properties
Cardinal functions
The cardinality of the space .
The cardinality of the topology (the set of open subsets) of the space .
Weight , the least cardinality of a basis of the topology of the space .
Density , the least cardinality of a subset of whose closure is .
Separation
Note that some of these terms are defined differently in older mathematical literature; see history of the separation axioms.
T0 or Kolmogorov. A space is Kolmogorov if for e
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https://en.wikipedia.org/wiki/Cross%20section
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Cross section may refer to:
Cross section (geometry)
Cross-sectional views in architecture & engineering 3D
Cross section (geology)
Cross section (electronics)
Radar cross section, measure of detectability
Cross section (physics)
Absorption cross section
Nuclear cross section
Neutron cross section
Photoionisation cross section
Gamma ray cross section
Cross Section (album), 1956 musical album by Billy Taylor
See also
Cross section (fiber), microscopic view of textile fibers.
Section (fiber bundle), in differential and algebraic geometry and topology, a section of a fiber bundle or sheaf
Cross-sectional data, in statistics, econometrics, and medical research, a data set drawn from a single point in time
Cross-sectional study, a scientific investigation utilizing cross-sectional data
Cross-sectional regression, a particular statistical technique for carrying out a cross-sectional study
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https://en.wikipedia.org/wiki/PLATO%20%28computational%20chemistry%29
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PLATO (Package for Linear-combination of ATomic Orbitals) is a suite of programs for electronic structure calculations. It receives its name from the choice of basis set (numeric atomic orbitals) used to expand the electronic wavefunctions.
PLATO is a code, written in C, for the efficient modelling of materials. It is a tight binding code (both orthogonal and non-orthogonal), allowing for multipole charges and electron spin. It also contains Density Functional Theory programs: these were restored to enable clear benchmarking to tight binding simulations, but can be used in their own right. The Density Functional Tight Binding program can be applied to systems with periodic boundary conditions in three dimension (crystals), as well as clusters and molecules.
How PLATO works
How PLATO performs Density Functional Theory is summarized in several papers:
. The way it performs tight binding is summarized in the following papers
Applications of PLATO
Some examples of its use are listed below.
Metals
Point defects in transition metals: Density functional theory calculations have been performed to study the systematic trends of point defect behaviours in bee transition metals.
Surfaces
Interaction of C60 molecules on Si(100):The interactions between pairs of C60 molecules adsorbed upon the Si(100) surface have been studied via a series of DFT calculations.
Molecules
Efficient local-orbitals based method for ultrafast dynamics: The evolution of electrons in molecules und
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https://en.wikipedia.org/wiki/Semisimple%20Lie%20algebra
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In mathematics, a Lie algebra is semisimple if it is a direct sum of simple Lie algebras. (A simple Lie algebra is a non-abelian Lie algebra without any non-zero proper ideals).
Throughout the article, unless otherwise stated, a Lie algebra is a finite-dimensional Lie algebra over a field of characteristic 0. For such a Lie algebra , if nonzero, the following conditions are equivalent:
is semisimple;
the Killing form, κ(x,y) = tr(ad(x)ad(y)), is non-degenerate;
has no non-zero abelian ideals;
has no non-zero solvable ideals;
the radical (maximal solvable ideal) of is zero.
Significance
The significance of semisimplicity comes firstly from the Levi decomposition, which states that every finite dimensional Lie algebra is the semidirect product of a solvable ideal (its radical) and a semisimple algebra. In particular, there is no nonzero Lie algebra that is both solvable and semisimple.
Semisimple Lie algebras have a very elegant classification, in stark contrast to solvable Lie algebras. Semisimple Lie algebras over an algebraically closed field of characteristic zero are completely classified by their root system, which are in turn classified by Dynkin diagrams. Semisimple algebras over non-algebraically closed fields can be understood in terms of those over the algebraic closure, though the classification is somewhat more intricate; see real form for the case of real semisimple Lie algebras, which were classified by Élie Cartan.
Further, the representation theory o
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https://en.wikipedia.org/wiki/Trough
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Trough may refer to:
In science
Trough (geology), a long depression less steep than a trench
Trough (meteorology), an elongated region of low atmospheric pressure
Trough (physics), the lowest point on a wave
Trough level (medicine), the lowest concentration of a medicine is present in the body over time
Langmuir-Blodgett trough, a laboratory instrument
In politics
Trough (economics), the lowest turning point of a business cycle
as metaphor for political corruption, in the contexts of crony capitalism, nepotism, and public economics
Other uses
Bread trough or dough trough, rectangular receptacle with a shallow basin, used in breadmaking
Trough (barony), a historical barony in County Monaghan, Ireland
Trough (food) or manger, a container for animal feed
Watering trough, a receptacle of drinking water for domestic and non-domestic livestock
Water trough, a trough used to supply water to steam locomotives.
Battle of the Trough, a 1756 skirmish of the French and Indian War in West Virginia
Sleightholme Beck Gorge - The Troughs, a Site of Special Scientific Interest in the Teesdale district of south-west County Durham, England
The Trough, a gorge carved by the South Branch Potomac River in West Virginia
"Down the trough", as used by Donegal Gaelic football club Cill Chartha
Trough, an old word for an inkwell
See also
Trow, a type of cargo boat
Troff, a document processing system developed by AT&T for the Unix operating system
"Tropho-", a Greek root meanin
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https://en.wikipedia.org/wiki/Andrew%20Appel
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Andrew Wilson Appel (born 1960) is the Eugene Higgins Professor of computer science at Princeton University. He is especially well-known because of his compiler books, the Modern Compiler Implementation in ML () series, as well as Compiling With Continuations (). He is also a major contributor to the Standard ML of New Jersey compiler, along with David MacQueen, John H. Reppy, Matthias Blume and others and one of the authors of Rog-O-Matic.
Biography
Andrew Appel is the son of mathematician Kenneth Appel, who proved the Four-Color Theorem in 1976. Appel graduated summa cum laude with an A.B. in physics from Princeton University in 1981 after completing a senior thesis, titled "Investigation of galaxy clustering using an asymptotically fast N-body algorithm", under the supervision of Nobel laureate James Peebles. He later received a Ph.D. (computer science) at Carnegie Mellon University, in 1985. He became an ACM Fellow in 1998, due to his research of programming languages and compilers.
In 1981, Appel developed a better approach to the -body problem in linearithmic instead of quadratic time.
From July 2005 to July 2006, he was a visiting researcher at the Institut national de recherche en informatique et en automatique (INRIA), Rocquencourt, France, on sabbatical from Princeton University.
Andrew Appel campaigns on issues related to the interaction of law and computer technology. He testified in the penalty phase of the Microsoft antitrust case in 2002. He is opposed to
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https://en.wikipedia.org/wiki/Corecursion
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In computer science, corecursion is a type of operation that is dual to recursion. Whereas recursion works analytically, starting on data further from a base case and breaking it down into smaller data and repeating until one reaches a base case, corecursion works synthetically, starting from a base case and building it up, iteratively producing data further removed from a base case. Put simply, corecursive algorithms use the data that they themselves produce, bit by bit, as they become available, and needed, to produce further bits of data. A similar but distinct concept is generative recursion which may lack a definite "direction" inherent in corecursion and recursion.
Where recursion allows programs to operate on arbitrarily complex data, so long as they can be reduced to simple data (base cases), corecursion allows programs to produce arbitrarily complex and potentially infinite data structures, such as streams, so long as it can be produced from simple data (base cases) in a sequence of finite steps. Where recursion may not terminate, never reaching a base state, corecursion starts from a base state, and thus produces subsequent steps deterministically, though it may proceed indefinitely (and thus not terminate under strict evaluation), or it may consume more than it produces and thus become non-productive. Many functions that are traditionally analyzed as recursive can alternatively, and arguably more naturally, be interpreted as corecursive functions that are terminat
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https://en.wikipedia.org/wiki/Infinite-dimensional%20holomorphy
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In mathematics, infinite-dimensional holomorphy is a branch of functional analysis. It is concerned with generalizations of the concept of holomorphic function to functions defined and taking values in complex Banach spaces (or Fréchet spaces more generally), typically of infinite dimension. It is one aspect of nonlinear functional analysis.
Vector-valued holomorphic functions defined in the complex plane
A first step in extending the theory of holomorphic functions beyond one complex dimension is considering so-called vector-valued holomorphic functions, which are still defined in the complex plane C, but take values in a Banach space. Such functions are important, for example, in constructing the holomorphic functional calculus for bounded linear operators.
Definition. A function f : U → X, where U ⊂ C is an open subset and X is a complex Banach space is called holomorphic if it is complex-differentiable; that is, for each point z ∈ U the following limit exists:
One may define the line integral of a vector-valued holomorphic function f : U → X along a rectifiable curve γ : [a, b] → U in the same way as for complex-valued holomorphic functions, as the limit of sums of the form
where a = t0 < t1 < ... < tn = b is a subdivision of the interval [a, b], as the lengths of the subdivision intervals approach zero.
It is a quick check that the Cauchy integral theorem also holds for vector-valued holomorphic functions. Indeed, if f : U → X is such a function and T : X → C a bo
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https://en.wikipedia.org/wiki/Oversampling
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In signal processing, oversampling is the process of sampling a signal at a sampling frequency significantly higher than the Nyquist rate. Theoretically, a bandwidth-limited signal can be perfectly reconstructed if sampled at the Nyquist rate or above it. The Nyquist rate is defined as twice the bandwidth of the signal. Oversampling is capable of improving resolution and signal-to-noise ratio, and can be helpful in avoiding aliasing and phase distortion by relaxing anti-aliasing filter performance requirements.
A signal is said to be oversampled by a factor of N if it is sampled at N times the Nyquist rate.
Motivation
There are three main reasons for performing oversampling: to improve anti-aliasing performance, to increase resolution and to reduce noise.
Anti-aliasing
Oversampling can make it easier to realize analog anti-aliasing filters. Without oversampling, it is very difficult to implement filters with the sharp cutoff necessary to maximize use of the available bandwidth without exceeding the Nyquist limit. By increasing the bandwidth of the sampling system, design constraints for the anti-aliasing filter may be relaxed. Once sampled, the signal can be digitally filtered and downsampled to the desired sampling frequency. In modern integrated circuit technology, the digital filter associated with this downsampling is easier to implement than a comparable analog filter required by a non-oversampled system.
Resolution
In practice, oversampling is implemented in order t
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https://en.wikipedia.org/wiki/Peter%20Borwein
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Peter Benjamin Borwein (born St. Andrews, Scotland, May 10, 1953 – 23 August 2020) was a Canadian mathematician
and a professor at Simon Fraser University. He is known as a co-author of the paper which presented the Bailey–Borwein–Plouffe algorithm (discovered by Simon Plouffe) for computing π.
First interest in mathematics
Borwein was born into a Jewish family. He became interested in number theory and classical analysis during his second year of university. He had not previously been interested in math, although his father was the head of the University of Western Ontario's mathematics department and his mother is associate dean of medicine there. Borwein and his two siblings majored in mathematics.
Academic career
After completing a Bachelor of Science in Honours Math at the University of Western Ontario in 1974, he went on to complete an MSc and Ph.D. at the University of British Columbia. He joined the Department of Mathematics at Dalhousie University. While he was there, he, his brother Jonathan Borwein and David H. Bailey of NASA wrote the 1989 paper that outlined and popularized a proof for computing one billion digits of π. The authors won the 1993 Chauvenet Prize and Merten M. Hasse Prize for this paper.
In 1993, he moved to Simon Fraser University, joining his brother Jonathan in establishing the Centre for Experimental and Constructive Mathematics (CECM) where he developed the Inverse Symbolic Calculator.
Research
In 1995, the Borweins collaborated with
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https://en.wikipedia.org/wiki/Dietmar%20Saupe
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Dietmar Saupe (born 1954) is a fractal researcher and professor of computer science, Department of Computer and Information Science, University of Konstanz, Germany.
Saupe's book, Chaos and Fractals, won the Association of American Publishers award for Best Mathematics Book of the Year in 1992. His current research interests include computer graphics, scientific visualization, and image processing.
External links
University of Konstanz bio
German computer scientists
1954 births
Living people
Date of birth missing (living people)
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https://en.wikipedia.org/wiki/Portable%20hole
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In various works of speculative fiction, a portable hole is a two-dimensional device that can be used to contravene the laws of physics by creating a passage through a solid surface, through which characters can move.
Notable uses
The 1955 Looney Tunes cartoon, The Hole Idea, presents a fictional account in which Calvin Q. Calculus invents the device. Another early Looney Tunes example, Beep Prepared from 1961, developed the trope further and features the Road Runner lifting a (previously ordinary) hole off the ground, carrying it, then laying it down for the Coyote to fall through; the hole in this case is mundane until the start of the gag, as opposed to an intentional scientific creation as in The Hole Idea. The concept was shown in The Beatles' 1968 movie, Yellow Submarine, where Ringo picks up a hole from the Sea of Holes, stores it in his pocket, and uses it later to release Sgt. Pepper's Band from captivity. In 1988, Who Framed Roger Rabbit again used a portable hole as a plot device. Detective Eddie Valiant is able to escape being crushed by a steamroller by using one, echoing the 1955 Looney Tunes gag. The 1988 cartoon series The New Adventures of Winnie the Pooh features a portable hole with similar properties in the episode "Bubble Trouble."
In the Dungeons & Dragons fantasy role-playing game, a portable hole is a circle of cloth made from phase spider webs, strands of ether and beams of starlight. When deployed, it creates an extradimensional space six feet
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https://en.wikipedia.org/wiki/G%20factor
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g factor may refer to:
g factor (psychometrics), a model used to describe the commonality between cognitive ability test results
g-factor (physics), a quantity related to the magnetic moment of an electron, nucleus, or other particle
The g Factor: The Science of Mental Ability, a book by Arthur R. Jensen about the psychometric concept
The g Factor: General Intelligence and Its Implications, a book by Chris Brand about the psychometric concept
See also
g-force
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https://en.wikipedia.org/wiki/Engel%27s%20theorem
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In representation theory, a branch of mathematics, Engel's theorem states that a finite-dimensional Lie algebra is a nilpotent Lie algebra if and only if for each , the adjoint map
given by , is a nilpotent endomorphism on ; i.e., for some k. It is a consequence of the theorem, also called Engel's theorem, which says that if a Lie algebra of matrices consists of nilpotent matrices, then the matrices can all be simultaneously brought to a strictly upper triangular form. Note that if we merely have a Lie algebra of matrices which is nilpotent as a Lie algebra, then this conclusion does not follow (i.e. the naïve replacement in Lie's theorem of "solvable" with "nilpotent", and "upper triangular" with "strictly upper triangular", is false; this already fails for the one-dimensional Lie subalgebra of scalar matrices).
The theorem is named after the mathematician Friedrich Engel, who sketched a proof of it in a letter to Wilhelm Killing dated 20 July 1890 . Engel's student K.A. Umlauf gave a complete proof in his 1891 dissertation, reprinted as .
Statements
Let be the Lie algebra of the endomorphisms of a finite-dimensional vector space V and a subalgebra. Then Engel's theorem states the following are equivalent:
Each is a nilpotent endomorphism on V.
There exists a flag such that ; i.e., the elements of are simultaneously strictly upper-triangulizable.
Note that no assumption on the underlying base field is required.
We note that Statement 2. for various and V is
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https://en.wikipedia.org/wiki/Artin%E2%80%93Mazur%20zeta%20function
|
In mathematics, the Artin–Mazur zeta function, named after Michael Artin and Barry Mazur, is a function that is used for studying the iterated functions that occur in dynamical systems and fractals.
It is defined from a given function as the formal power series
where is the set of fixed points of the th iterate of the function , and is the number of fixed points (i.e. the cardinality of that set).
Note that the zeta function is defined only if the set of fixed points is finite for each . This definition is formal in that the series does not always have a positive radius of convergence.
The Artin–Mazur zeta function is invariant under topological conjugation.
The Milnor–Thurston theorem states that the Artin–Mazur zeta function of an interval map is the inverse of the kneading determinant of .
Analogues
The Artin–Mazur zeta function is formally similar to the local zeta function, when a diffeomorphism on a compact manifold replaces the Frobenius mapping for an algebraic variety over a finite field.
The Ihara zeta function of a graph can be interpreted as an example of the Artin–Mazur zeta function.
See also
Lefschetz number
Lefschetz zeta-function
References
Zeta and L-functions
Dynamical systems
Fixed points (mathematics)
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https://en.wikipedia.org/wiki/Ihara%20zeta%20function
|
In mathematics, the Ihara zeta function is a zeta function associated with a finite graph. It closely resembles the Selberg zeta function, and is used to relate closed walks to the spectrum of the adjacency matrix. The Ihara zeta function was first defined by Yasutaka Ihara in the 1960s in the context of discrete subgroups of the two-by-two p-adic special linear group. Jean-Pierre Serre suggested in his book Trees that Ihara's original definition can be reinterpreted graph-theoretically. It was Toshikazu Sunada who put this suggestion into practice in 1985. As observed by Sunada, a regular graph is a Ramanujan graph if and only if its Ihara zeta function satisfies an analogue of the Riemann hypothesis.
Definition
The Ihara zeta function is defined as the analytic continuation of the infinite product
where L(p) is the length of .
The product in the definition is taken over all prime closed geodesics of the graph , where geodesics which differ by a cyclic rotation are considered equal. A closed geodesic on (known in graph theory as a "reduced closed walk"; it is not a graph geodesic) is a finite sequence of vertices such that
The integer is the length . The closed geodesic is prime if it cannot be obtained by repeating a closed geodesic times, for an integer .
This graph-theoretic formulation is due to Sunada.
Ihara's formula
Ihara (and Sunada in the graph-theoretic setting) showed that for regular graphs the zeta function is a rational function.
If is a -regul
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https://en.wikipedia.org/wiki/Lerch%20zeta%20function
|
In mathematics, the Lerch zeta function, sometimes called the Hurwitz–Lerch zeta function, is a special function that generalizes the Hurwitz zeta function and the polylogarithm. It is named after Czech mathematician Mathias Lerch, who published a paper about the function in 1887.
Definition
The Lerch zeta function is given by
A related function, the Lerch transcendent, is given by
.
The transcendent only converges for any real number , where:
, or
, and .
The two are related, as
Integral representations
The Lerch transcendent has an integral representation:
The proof is based on using the integral definition of the Gamma function to write
and then interchanging the sum and integral. The resulting integral representation converges for Re(s) > 0, and Re(a) > 0. This analytically continues to z outside the unit disk. The integral formula also holds if z = 1, Re(s) > 1, and Re(a) > 0; see Hurwitz zeta function.
A contour integral representation is given by
where C is a Hankel contour counterclockwise around the positive real axis, not enclosing any of the points (for integer k) which are poles of the integrand. The integral assumes Re(a) > 0.
Other integral representations
A Hermite-like integral representation is given by
for
and
for
Similar representations include
and
holding for positive z (and more generally wherever the integrals converge). Furthermore,
The last formula is also known as Lipschitz formula.
Special cases
The Lerch zeta function and
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