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https://en.wikipedia.org/wiki/Gravitational%20anomaly
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In theoretical physics, a gravitational anomaly is an example of a gauge anomaly: it is an effect of quantum mechanics — usually a one-loop diagram—that invalidates the general covariance of a theory of general relativity combined with some other fields. The adjective "gravitational" is derived from the symmetry of a gravitational theory, namely from general covariance. A gravitational anomaly is generally synonymous with diffeomorphism anomaly, since general covariance is symmetry under coordinate reparametrization; i.e. diffeomorphism.
General covariance is the basis of general relativity, the classical theory of gravitation. Moreover, it is necessary for the consistency of any theory of quantum gravity, since it is required in order to cancel unphysical degrees of freedom with a negative norm, namely gravitons polarized along the time direction. Therefore, all gravitational anomalies must cancel out.
The anomaly usually appears as a Feynman diagram with a chiral fermion running in the loop (a polygon) with n external gravitons attached to the loop where where is the spacetime dimension.
Gravitational anomalies
Consider a classical gravitational field represented by the vielbein and a quantized Fermi field . The generating functional for this quantum field is
where is the quantum action and the factor before the Lagrangian is the vielbein determinant, the variation of the quantum action renders
in which we denote a mean value with respect to the path integral by
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https://en.wikipedia.org/wiki/Gauge%20anomaly
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In theoretical physics, a gauge anomaly is an example of an anomaly: it is a feature of quantum mechanics—usually a one-loop diagram—that invalidates the gauge symmetry of a quantum field theory; i.e. of a gauge theory.
All gauge anomalies must cancel out. Anomalies in gauge symmetries lead to an inconsistency, since a gauge symmetry is required in order to cancel degrees of freedom with a negative norm which are unphysical (such as a photon polarized in the time direction). Indeed, cancellation occurs in the Standard Model.
The term gauge anomaly is usually used for vector gauge anomalies. Another type of gauge anomaly is the gravitational anomaly, because coordinate reparametrization (called a diffeomorphism) is the gauge symmetry of gravitation.
Calculation of the anomaly
Anomalies occur only in even spacetime dimensions. For example, the anomalies in the usual 4 spacetime dimensions arise from triangle Feynman diagrams.
Vector gauge anomalies
In vector gauge anomalies (in gauge symmetries whose gauge boson is a vector), the anomaly is a chiral anomaly, and can be calculated exactly at one loop level, via a Feynman diagram with a chiral fermion running in the loop with n external gauge bosons attached to the loop where where is the spacetime dimension.
Let us look at the (semi)effective action we get after integrating over the chiral fermions. If there is a gauge anomaly, the resulting action will not be gauge invariant. If we denote by the operator correspondi
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https://en.wikipedia.org/wiki/Mixed%20anomaly
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In theoretical physics, a mixed anomaly is an example of an anomaly: it is an effect of quantum mechanics — usually a one-loop diagram — that implies that the classically valid general covariance and gauge symmetry of a theory of general relativity combined with gauge fields and fermionic fields cannot be preserved simultaneously in the quantum theory.
The adjective "mixed" usually refers to a mixture of a gravitational anomaly and gauge anomaly, but may also refer to a mixture of two different gauge groups tensored together, like the SU(2) and the U(1) of the Standard Model.
The anomaly usually appears as a Feynman diagram with a chiral fermion running in the loop (a polygon) with n−k external gravitons and k external gauge bosons attached to the loop where where is the spacetime dimension. Chiral fermions only occur in even spacetime dimensions. For example, the anomalies in the usual 4 spacetime dimensions arise from triangle Feynman diagrams.
General covariance and gauge symmetries are very important symmetries for the consistency of the whole theory, and therefore all gravitational, gauge, and mixed anomalies must cancel out.
References
See also
Gravitational anomaly
Green–Schwarz mechanism
Anomalies (physics)
Quantum gravity
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https://en.wikipedia.org/wiki/Henry%20Petroski
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Henry Petroski (February 6, 1942 – June 14, 2023) was an American engineer specializing in failure analysis. A professor both of civil engineering and history at Duke University, he was also a prolific author. Petroski has written over a dozen books – beginning with To Engineer is Human: The Role of Failure in Successful Design (1985) and including a number of titles detailing the industrial design history of common, everyday objects, such as pencils, paper clips, toothpicks, and silverware. His first book was made into the film When Engineering Fails. He was a frequent lecturer and a columnist for the magazines American Scientist and Prism.
Life and education
Petroski was born in Brooklyn, New York, and was raised in Park Slope and Cambria Heights, Queens. In 1963, he received his bachelor's degree from Manhattan College. He graduated with his PhD in Theoretical and Applied Mechanics from the University of Illinois at Urbana-Champaign in 1968.
Career
Before beginning his work at Duke in 1980, Petroski worked at the University of Texas at Austin from 1968–74 and for the Argonne National Laboratory from 1975–80. Petroski was the Aleksandar S. Vesic Professor of Civil Engineering and a professor of history at Duke University.
In 2004, Petroski was appointed to the United States Nuclear Waste Technical Review Board and was reappointed in 2008.
Petroski had received honorary degrees from Clarkson University, Trinity College, Valparaiso University and Manhattan College. He w
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https://en.wikipedia.org/wiki/Global%20anomaly
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In theoretical physics, a global anomaly is a type of anomaly: in this particular case, it is a quantum effect that invalidates a large gauge transformation that would otherwise be preserved in the classical theory. This leads to an inconsistency in the theory because the space of configurations which is being integrated over in the functional integral involves both a configuration and the same configuration after a large gauge transformation has acted upon it and the sum of all such contributions is zero and the space of configurations cannot be split into connected components for which the integral is nonzero.
Alternatively, the existence of a global anomaly implies that the measure of Feynman's functional integral cannot be defined globally.
The adjective "global" refers to the properties of a group that are detectable via large gauge or diffeomorphism transformations, but are not detectable locally via infinitesimal transformations. For example, all features of a discrete group (as opposed to a Lie group) are global in character.
A famous example is an SU(2) Yang–Mills theory in 4D with an odd number of chiral fermions in the fundamental representation 2 or the isospin 1/2 of SU(2), transforming as doublets under SU(2). This is known as the Witten SU(2) anomaly.
Another new but much more subtle example is found in 2018, also for the SU(2) gauge theory in 4D, with an odd number of chiral fermions in the representation 4 or the isospin 3/2 of SU(2). This is known as th
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https://en.wikipedia.org/wiki/Discrete%20symmetry
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In mathematics and geometry, a discrete symmetry is a symmetry that describes non-continuous changes in a system. For example, a square possesses discrete rotational symmetry, as only rotations by multiples of right angles will preserve the square's original appearance. Discrete symmetries sometimes involve some type of 'swapping', these swaps usually being called reflections or interchanges. In mathematics and theoretical physics, a discrete symmetry is a symmetry under the transformations of a discrete group—e.g. a topological group with a discrete topology whose elements form a finite or a countable set.
One of the most prominent discrete symmetries in physics is parity symmetry. It manifests itself in various elementary physical quantum systems, such as quantum harmonic oscillator, electron orbitals of Hydrogen-like atoms by forcing wavefunctions to be even or odd. This in turn gives rise to selection rules that determine which transition lines are visible in atomic absorption spectra.
References
Slavik V. Jablan, Symmetry, Ornament and Modularity, Volume 30 of K & E Series on Knots and Everything, World Scientific, 2002.
Group theory
Theoretical physics
Symmetry
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https://en.wikipedia.org/wiki/Modular%20invariance
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In theoretical physics, modular invariance is the invariance under the group such as SL(2,Z) of large diffeomorphisms of the torus. The name comes from the classical name modular group of this group, as in modular form theory.
In string theory, modular invariance is an additional requirement for one-loop diagrams. This helps in getting rid of some global anomalies such as the gravitational anomalies.
Equivalently, in two-dimensional conformal field theory the torus partition function must be invariant under the modular group SL(2,Z).
String theory
Symmetry
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https://en.wikipedia.org/wiki/Coleman%E2%80%93Mandula%20theorem
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In theoretical physics, the Coleman–Mandula theorem is a no-go theorem stating that spacetime and internal symmetries can only combine in a trivial way. This means that the charges associated with internal symmetries must always transform as Lorentz scalars. Some notable exceptions to the no-go theorem are conformal symmetry and supersymmetry. It is named after Sidney Coleman and Jeffrey Mandula who proved it in 1967 as the culmination of a series of increasingly generalized no-go theorems investigating how internal symmetries can be combined with spacetime symmetries. The supersymmetric generalization is known as the Haag–Łopuszański–Sohnius theorem.
History
In the early 1960s, the global symmetry associated with the eightfold way was shown to successfully describe the hadron spectrum for hadrons of the same spin. This led to efforts to expand the global symmetry to a larger symmetry mixing both flavour and spin, an idea similar to that previously considered in nuclear physics by Eugene Wigner in 1937 for an symmetry. This non-relativistic model united vector and pseudoscalar mesons of different spin into a 35-dimensional multiplet and it also united the two baryon decuplets into a 56-dimensional multiplet. While this was reasonably successful in describing various aspects of the hadron spectrum, from the perspective of quantum chromodynamics this success is merely a consequence of the flavour and spin independence of the force between quarks. There were many attempts
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https://en.wikipedia.org/wiki/No-go%20theorem
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In theoretical physics, a no-go theorem is a theorem that states that a particular situation is not physically possible. Specifically, the term describes results in quantum mechanics like Bell's theorem and the Kochen–Specker theorem that constrain the permissible types of hidden variable theories which try to explain the apparent randomness of quantum mechanics as a deterministic model featuring hidden states.
Instances of no-go theorems
Full descriptions of the no-go theorems named below are given in other articles linked to their names. A few of them are broad, general categories under which several theorems fall. Other names are broad and general-sounding but only refer to a single theorem.
Classical electrodynamics
Antidynamo theorems is a general category of theorems that restrict the type of magnetic fields that can be produced by dynamo action.
Earnshaw's theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges.
Non-relativistic quantum Mechanics and quantum information
Bell's theorem
Kochen–Specker theorem
PBR theorem
No-hiding theorem
No-cloning theorem
Quantum no-deleting theorem
No-teleportation theorem
No-broadcast theorem
The no-communication theorem in quantum information theory gives conditions under which instantaneous transfer of information between two observers is impossible.
No-programming theorem
Quantum field theory and
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https://en.wikipedia.org/wiki/Jeffrey%20Mandula
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Jeffrey Ellis Mandula (born 1941 in New York City) is a physicist well known for the Coleman–Mandula theorem from 1967. He got his Ph.D. 1966 under Sidney Coleman at Harvard University. Thereafter he was a professor of applied mathematics at MIT and then of physics at Washington University in St. Louis. Today, he is responsible for the funding of science in the U.S. Department of Energy.
References
A timeline of mathematics and theoretical physics 1967 at superstringtheory.com
Federal Grants Alert: August 30, 2000 (Department of Energy (DOE)) at U.S. House of Representatives, Washington, DC 20515
21st-century American physicists
Washington University in St. Louis faculty
Washington University physicists
Washington University in St. Louis mathematicians
Harvard University alumni
1941 births
Living people
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https://en.wikipedia.org/wiki/Mandelstam%20variables
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In theoretical physics, the Mandelstam variables are numerical quantities that encode the energy, momentum, and angles of particles in a scattering process in a Lorentz-invariant fashion. They are used for scattering processes of two particles to two particles. The Mandelstam variables were first introduced by physicist Stanley Mandelstam in 1958.
If the Minkowski metric is chosen to be , the Mandelstam variables are then defined by
,
where p1 and p2 are the four-momenta of the incoming particles and p3 and p4 are the four-momenta of the outgoing particles.
is also known as the square of the center-of-mass energy (invariant mass) and as the square of the four-momentum transfer.
Feynman diagrams
The letters s,t,u are also used in the terms s-channel (timelike channel), t-channel, and u-channel (both spacelike channels). These channels represent different Feynman diagrams or different possible scattering events where the interaction involves the exchange of an intermediate particle whose squared four-momentum equals s,t,u, respectively.
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|align="center"|s-channel
|align="center"|t-channel
|align="center"|u-channel
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For example, the s-channel corresponds to the particles 1,2 joining into an intermediate particle that eventually splits into 3,4: The t-channel represents the process in which the particle 1 emits the intermediate particle and becomes the final particle 3, while the particle 2 absorbs the intermediate particle and becomes 4. The
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https://en.wikipedia.org/wiki/Seesaw%20mechanism
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In the theory of grand unification of particle physics, and, in particular, in theories of neutrino masses and neutrino oscillation, the seesaw mechanism is a generic model used to understand the relative sizes of observed neutrino masses, of the order of eV, compared to those of quarks and charged leptons, which are millions of times heavier. The name of the seesaw mechanism was given by Tsutomu Yanagida in a Tokyo conference in 1981.
There are several types of models, each extending the Standard Model. The simplest version, "Type 1," extends the Standard Model by assuming two or more additional right-handed neutrino fields
inert under the electroweak interaction,
and the existence of a very large mass scale. This allows the mass scale to be identifiable with the postulated scale of grand unification.
Type 1 seesaw
This model produces a light neutrino, for each of the three known neutrino flavors, and a corresponding very heavy neutrino for each flavor, which has yet to be observed.
The simple mathematical principle behind the seesaw mechanism is the following property of any 2×2 matrix of the form
It has two eigenvalues:
and
The geometric mean of and equals , since the determinant .
Thus, if one of the eigenvalues goes up, the other goes down, and vice versa. This is the point of the name "seesaw" of the mechanism.
In applying this model to neutrinos, is taken to be much larger than
Then the larger eigenvalue, is approximately equal to while the smaller eig
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https://en.wikipedia.org/wiki/Soft%20SUSY%20breaking
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In theoretical physics, soft SUSY breaking is type of supersymmetry breaking that does not cause ultraviolet divergences to appear in scalar masses.
Overview
These terms are relevant operators—i.e. operators whose coefficients have a positive dimension of mass—though there are some exceptions.
A model with soft SUSY breaking was proposed in 1981 by Howard Georgi and Savas Dimopoulos. Before this, dynamical models of supersymmetry breaking were being used that suffered from giving rise to color and charge breaking vacua.
Soft SUSY breaking decouples the origin of supersymmetry breaking from its phenomenological consequences. In effect, soft SUSY breaking adds explicit symmetry breaking to the supersymmetric Standard Model Lagrangian. The source of SUSY breaking results from a different sector where supersymmetry is broken spontaneously. Divorcing the spontaneous supersymmetry breaking from the supersymmetric Standard Model leads to the notion of mediated supersymmetry breaking.
Example operators
Gaugino mass
Scalar masses
Scalar trilinear interactions ("A-terms")
Nonholomorphic soft supersymmetry breaking interactions
In low energy supersymmetry based models, the soft supersymmetry breaking interactions excepting the mass terms are usually considered to be holomorphic functions of fields. While a superpotential such as that of MSSM needs to be holomorphic, there is no reason why soft supersymmetry breaking interactions are required to be holomorphic functions of
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https://en.wikipedia.org/wiki/Rooted%20graph
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In mathematics, and, in particular, in graph theory, a rooted graph is a graph in which one vertex has been distinguished as the root. Both directed and undirected versions of rooted graphs have been studied, and there are also variant definitions that allow multiple roots.
Rooted graphs may also be known (depending on their application) as pointed graphs or flow graphs. In some of the applications of these graphs, there is an additional requirement that the whole graph be reachable from the root vertex.
Variations
In topological graph theory, the notion of a rooted graph may be extended to consider multiple vertices or multiple edges as roots. The former are sometimes called vertex-rooted graphs in order to distinguish them from edge-rooted graphs in this context. Graphs with multiple nodes designated as roots are also of some interest in combinatorics, in the area of random graphs. These graphs are also called multiply rooted graphs.
The terms rooted directed graph or rooted digraph also see variation in definitions. The obvious transplant is to consider a digraph rooted by identifying a particular node as root. However, in computer science, these terms commonly refer to a narrower notion; namely, a rooted directed graph is a digraph with a distinguished node r, such that there is a directed path from r to any node other than r. Authors who give the more general definition may refer to as connected rooted digraphs or accessible rooted graphs (see ).
The Art of Comput
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https://en.wikipedia.org/wiki/Hyundai
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Hyundai is a South Korean industrial conglomerate ("chaebol"), which was restructured into the following groups:
Hyundai Group, parts of the former conglomerate which have not been divested
Hyundai Asan, a real estate construction and civil engineering company
Hyundai Motor Group, the automotive part of the former conglomerate
Hyundai Motor Company, an automobile manufacturer
Hyundai N
Hyundai Motor India
Hyundai Mobis, Korean car parts company
Hyundai Motorsport, a racing team
Hyundai Rotem, a manufacturer of railway vehicles, defense systems, and factory equipment
Hyundai Engineering & Construction, a construction company
Hyundai Heavy Industries Group, the heavy industry part of the former conglomerate
Hyundai Heavy Industries, the primary company representing the group
Hyundai Mipo Dockyard, a shipbuilding company
Hyundai Samho Heavy Industries, a shipbuilding company
Hyundai Oilbank, a petroleum refinery company
Hyundai Department Store Group, the retail division of the former conglomerate
Hyundai Department Store, a department store chain
Hyundai Development Company, a construction and civil engineering company
Hyundai EP, a manufacturer of petrochemicals and plastics
Hyundai Fomex, a professional lighting manufacturer
Hyundai Marine & Fire Insurance, an insurance company
Hyundai Corporation, a trading and industrial investment company
Hyundai Electronics, a chip manufacturer, spun off as Hynix in 2001 and renamed SK Hynix in 2012
See also
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https://en.wikipedia.org/wiki/Index%20of%20molecular%20biology%20articles
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This is a list of topics in molecular biology. See also index of biochemistry articles.
#
2-amino-4-deoxychorismate dehydrogenase - 2-dehydropantolactone reductase (B-specific) - 2-methylacyl-CoA dehydrogenase - 2-nitropropane dioxygenase - 2-oxobutyrate synthase - (2,3-dihydroxybenzoyl)adenylate synthase - 2,4-Dihydroxy-1,4-benzoxazin-3-one-glucoside dioxygenase - 2010107G12Rik - 27-hydroxycholesterol 7alpha-monooxygenase - 3' end - 3' flanking region - 3-hydroxy-2-methylpyridinecarboxylate dioxygenase - 3-Ketosteroid 9alpha-monooxygenase - 3-oxoacyl-(acyl-carrier-protein) reductase (NADH) - (3,5-dihydroxyphenyl)acetyl-CoA 1,2-dioxygenase - 3(or 17)a-hydroxysteroid dehydrogenase - 3110001I22Rik - 3alpha-hydroxyglycyrrhetinate dehydrogenase - 4932414N04Rik - 3alpha-hydroxysteroid dehydrogenase (A-specific) - 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestanoyl-CoA 24-hydroxylase - 3alpha,7alpha,12alpha-trihydroxycholestan-26-al 26-oxidoreductase - 4-Cresol dehydrogenase (hydroxylating) - 4-Hydroxycyclohexanecarboxylate dehydrogenase - 4-hydroxyphenylacetaldehyde oxime monooxygenase - 4-hydroxyphenylpyruvate oxidase - 4-Nitrophenol 4-monooxygenase - 4933425L06Rik - 5' end - 5' flanking region - 5-pyridoxate dioxygenase - 6-endo-hydroxycineole dehydrogenase - 7-deoxyloganin 7-hydroxylase - 7beta-hydroxysteroid dehydrogenase (NADP+) - 8-oxocoformycin reductase - 12beta-hydroxysteroid dehydrogenase - 25-hydroxycholesterol 7α-hydroxylase -
A
abietadiene hydroxylase - acrylam
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https://en.wikipedia.org/wiki/Additive%20polynomial
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In mathematics, the additive polynomials are an important topic in classical algebraic number theory.
Definition
Let k be a field of prime characteristic p. A polynomial P(x) with coefficients in k is called an additive polynomial, or a Frobenius polynomial, if
as polynomials in a and b. It is equivalent to assume that this equality holds for all a and b in some infinite field containing k, such as its algebraic closure.
Occasionally absolutely additive is used for the condition above, and additive is used for the weaker condition that P(a + b) = P(a) + P(b) for all a and b in the field. For infinite fields the conditions are equivalent, but for finite fields they are not, and the weaker condition is the "wrong" as it does not behave well. For example, over a field of order q any multiple P of xq − x will satisfy P(a + b) = P(a) + P(b) for all a and b in the field, but will usually not be (absolutely) additive.
Examples
The polynomial xp is additive. Indeed, for any a and b in the algebraic closure of k one has by the binomial theorem
Since p is prime, for all n = 1, ..., p−1 the binomial coefficient is divisible by p, which implies that
as polynomials in a and b.
Similarly all the polynomials of the form
are additive, where n is a non-negative integer.
The definition makes sense even if k is a field of characteristic zero, but in this case the only additive polynomials are those of the form ax for some a in k.
The ring of additive polynomials
It is qu
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https://en.wikipedia.org/wiki/Doublet%E2%80%93triplet%20splitting%20problem
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In particle physics, the doublet–triplet (splitting) problem is a problem of some Grand Unified Theories, such as SU(5), SO(10), and . Grand unified theories predict Higgs bosons (doublets of ) arise from representations of the unified group that contain other states, in particular, states that are triplets of color. The primary problem with these color triplet Higgs is that they can mediate proton decay in supersymmetric theories that are only suppressed by two powers of GUT scale (i.e. they are dimension 5 supersymmetric operators). In addition to mediating proton decay, they alter gauge coupling unification. The doublet–triplet problem is the question 'what keeps the doublets light while the triplets are heavy?'
Doublet–triplet splitting and the μ-problem
In 'minimal' SU(5), the way one accomplishes doublet–triplet splitting is through a combination of interactions
where is an adjoint of SU(5) and is traceless. When acquires a vacuum expectation value
that breaks SU(5) to the Standard Model gauge symmetry the Higgs doublets and triplets acquire a mass
Since is at the GUT scale ( GeV) and the Higgs doublets need to have a weak scale mass (100 GeV), this requires
.
So to solve this doublet–triplet splitting problem requires a tuning of the two terms to within one part in .
This is also why the mu problem of the MSSM (i.e. why are the Higgs doublets so light) and doublet–triplet splitting are so closely intertwined.
Solutions to the doublet-triplet splitting
The
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https://en.wikipedia.org/wiki/Functional%20%28mathematics%29
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In mathematics, a functional is a certain type of function. The exact definition of the term varies depending on the subfield (and sometimes even the author).
In linear algebra, it is synonymous with a linear form, which is a linear mapping from a vector space into its field of scalars (that is, it is an element of the dual space )
In functional analysis and related fields, it refers more generally to a mapping from a space into the field of real or complex numbers. In functional analysis, the term is a synonym of linear form; that is, it is a scalar-valued linear map. Depending on the author, such mappings may or may not be assumed to be linear, or to be defined on the whole space
In computer science, it is synonymous with a higher-order function, which is a function that takes one or more functions as arguments or returns them.
This article is mainly concerned with the second concept, which arose in the early 18th century as part of the calculus of variations. The first concept, which is more modern and abstract, is discussed in detail in a separate article, under the name linear form. The third concept is detailed in the computer science article on higher-order functions.
In the case where the space is a space of functions, the functional is a "function of a function", and some older authors actually define the term "functional" to mean "function of a function".
However, the fact that is a space of functions is not mathematically essential, so this older definit
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https://en.wikipedia.org/wiki/Andrew%20Lyne
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Andrew Geoffrey Lyne (born 13 July 1942) is a British physicist. Lyne is Langworthy Professor of Physics in the School of Physics and Astronomy, University of Manchester, as well as an ex-director of the Jodrell Bank Observatory. Despite retiring in 2007 he remains an active researcher within the Jodrell Bank Pulsar Group. Lyne was educated at The Portsmouth Grammar School, the Royal Naval School, Tal Handaq, Malta and at St. John's College at the University of Cambridge (natural sciences), continuing to the University of Manchester for a PhD in Radio Astronomy. Lyne writes that he is "mostly interested in finding and understanding radio pulsars in all their various forms and with their various companions. Presently, I am most occupied with the development of new multibeam search systems at Jodrell and Parkes, in order to probe deeper into the Galaxy, particularly for millisecond pulsars, young pulsars and any that might be in binary systems."
Claimed pulsar planet
In 1991, Andrew Lyne and Matthew Bailes reported that they had discovered a pulsar orbited by a planetary companion; this would have been the first planet detected around another star. However, after this was announced, the group went back and checked their work, and found that they had not properly removed the effects of the Earth's motion around the Sun from their analysis, and, when the calculations were redone correctly, the pulse variations that led to their conclusions disappeared, and that there was in
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https://en.wikipedia.org/wiki/Roger%20Mayne
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Roger Mayne (5 May 1929 – 7 June 2014) was an English photographer, best known for his documentation of the children of Southam Street, London.
Life and work
Born in Cambridge, Mayne studied Chemistry at Balliol College, Oxford University. Here he became interested in photographic processing, and met Hugo van Wadenoyen, a key figure in British photography's break with pictorialism. On graduating in 1951 Mayne contributed pictures to Picture Post, and was an occasional film stills photographer. In the early 1950s he made photographic portraits of many residents in the artist's-colony town of St. Ives, Cornwall. He operated very much in an aesthetic vacuum, struggling to find any coherent tradition of British photography to follow. In 1956 he had a one-man show of his portraits at the ICA (UK), and George Eastman House (US). By 1957 he was established as a freelance photographer for London magazines and book-jacket designers.
With some financial and limited curatorial security established, he began to look for a significant personal project. He found it in the street life of Southam Street in Notting Dale (now often considered part of Notting Hill), which he photographed between 1956 and 1961. The novelist Colin MacInnes asked Mayne to contribute the cover shot for Absolute Beginners (1959), which is set in the area around Southam Street. The Southam Street collection is of national importance, and is now held by the Victoria and Albert Museum, London.
Most of Southam Stre
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https://en.wikipedia.org/wiki/Landscape%20engineering
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Landscape engineering is the application of mathematics and science to shape land and waterscapes. It can also be described as green engineering, but the design professionals best known for landscape engineering are landscape architects. Landscape engineering is the interdisciplinary application of engineering and other applied sciences to the design and creation of anthropogenic landscapes. It differs from, but embraces traditional reclamation. It includes scientific disciplines: Agronomy, Botany, Ecology, Forestry, Geology, Geochemistry, Hydrogeology, and Wildlife Biology. It also draws upon applied sciences: Agricultural & Horticultural Sciences, Engineering Geomorphology, landscape architecture, and Mining, Geotechnical, and Civil, Agricultural & Irrigation Engineering.
Landscape engineering builds on the engineering strengths of declaring goals, determining initial conditions, iteratively designing, predicting performance based on knowledge of the design, monitoring performance, and adjusting designs to meet the declared goals. It builds on the strengths and history of reclamation practice. Its distinguishing feature is the marriage of landforms, substrates, and vegetation throughout all phases of design and construction, which previously have been kept as separate disciplines.
Though landscape engineering embodies all elements of traditional engineering (planning, investigation, design, construction, operation, assessment, research, management, and training), it is fo
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https://en.wikipedia.org/wiki/Institut%20national%20de%20physique%20nucl%C3%A9aire%20et%20de%20physique%20des%20particules
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The French National Institute of Nuclear and Particle Physics (French: Institut national de physique nucléaire et de physique des particules, IN2P3) is the coordinating body for nuclear and particle physics in France. It was established in 1971 as a division of the French National Centre for Scientific Research (CNRS). Its purpose is "to promote and unite research activities in the various fields of physics".
List of IN2P3 institutes
Strasbourg
The Hubert Curien Multi-disciplinary Institute (l'Institut Pluridisciplinaire Hubert Curien, IPHC)
Annecy
The Annecy Particle Physics Laboratory (le Laboratoire d'Annecy de physique des particules, LAPP) at the Université Savoie Mont Blanc
Lyon
The Institute of Nuclear Physics of Lyon (l'Institut de physique nucléaire de Lyon, IPNL) at Claude Bernard University Lyon 1
The IN2P3 Computing Centre (le Centre de calcul, CC-IN2P3)
The Advanced Materials Laboratory (le Laboratoire des matériaux avancés, LMA)
Modane
The Modane Underground Laboratory (le Laboratoire souterrain de Modane, LSM)
Grenoble
The Laboratory of Subatomic Physics and Cosmology (le Laboratoire de physique subatomique et de cosmologie de Grenoble, LPSC) at the Université Grenoble Alpes
Marseille
The Centre for Particle Physics of Marseille (le Centre de physique des particules de Marseille, CPPM) at Aix-Marseille University
Montpellier
(le Laboratoire Univers et Particules de Montpellier, LUPM) at the University of Montpellier
Clermont-Ferrand
T
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https://en.wikipedia.org/wiki/Stochastic%20vacuum%20model
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In physics, the stochastic vacuum model is a nonperturbative, phenomenological approach to derive cross section in quantum chromodynamics.
It is deemed impossible to calculate the vacuum averages of gauge-invariant quantities in QCD in a closed form, e.g. using the path integrals. But standard perturbation theory techniques don't work at distances, where the running coupling constant reaches 1.
The stochastic vacuum model is based on the approximation of nonperturbative QCD as a Gaussian process. It allows to calculate Wilson loops.
See also
Stochastic quantum mechanics
References
Field correlators in QCD A. Di Giacomo, H.G. Dosch, V.I. Shevchenko, Yu.A. Simonov, Phys. Repts. 372 319-368 (2002)
Pomeron Physics and QCD S. Donnachie, H.G. Dosch, P. Landshoff, O. Nachtmann C U P (2002)
Quantum chromodynamics
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https://en.wikipedia.org/wiki/Leverage%20%28finance%29
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In finance, leverage (or gearing in the United Kingdom and Australia) is any technique involving borrowing funds to buy an investment, estimating that future profits will be more than the cost of borrowing. This technique is named after a lever in physics, which amplifies a small input force into a greater output force, because successful leverage amplifies the smaller amounts of money needed for borrowing into large amounts of profit. However, the technique also involves the high risk of not being able to pay back a large loan. Normally, a lender will set a limit on how much risk it is prepared to take and will set a limit on how much leverage it will permit, and would require the acquired asset to be provided as collateral security for the loan.
Leveraging enables gains to be multiplied. On the other hand, losses are also multiplied, and there is a risk that leveraging will result in a loss if financing costs exceed the income from the asset, or the value of the asset falls.
Sources
Leverage can arise in a number of situations, such as:
securities like options and futures are effectively bets between parties where the principal is implicitly borrowed/lent at interest rates of very short treasury bills.
equity owners of businesses leverage their investment by having the business borrow a portion of its needed financing. The more it borrows, the less equity it needs, so any profits or losses are shared among a smaller base and are proportionately larger as a result.
bus
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https://en.wikipedia.org/wiki/Trimorphism
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In biology, trimorphism is the existence in certain plants and animals of three distinct forms, especially in connection with the reproductive organs.
In trimorphic plants there are three forms, differing in the lengths of their pistils and stamens, in size and color of their pollen grains, and in some other respects; and, as in each of the three forms there are two sets of stamens, the three forms possess altogether six sets of stamens and three kinds of pistils. These organs are so proportioned in length to each other that half the stamens in two of the forms stand on a level with the stigma of the third form. To obtain full fertility with these plants, it is necessary that the stigma of the one should be fertilized by pollen taken from the stamens of corresponding height in another form. Hence six unions are legitimate, that is, fully fertile, and 12 are illegitimate, or more or less unfertile. Wallace has shown that the females of certain butterflies from the Malay Archipelago appear in three conspicuously distinct forms without intermediate links.
In crystallography, trimorphism refers to the occurrence of certain forms in minerals which have the same chemical composition, but are referable to three systems of crystallization.
See also
Sexual dimorphism
Notes
Text from Collier's New Encyclopedia (1921).
Plant physiology
Pollination
Sex
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https://en.wikipedia.org/wiki/Scapegoat%20tree
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In computer science, a scapegoat tree is a self-balancing binary search tree, invented by Arne Andersson in 1989 and again by Igal Galperin and Ronald L. Rivest in 1993. It provides worst-case lookup time (with as the number of entries) and amortized insertion and deletion time.
Unlike most other self-balancing binary search trees which also provide worst case lookup time, scapegoat trees have no additional per-node memory overhead compared to a regular binary search tree: besides key and value, a node stores only two pointers to the child nodes. This makes scapegoat trees easier to implement and, due to data structure alignment, can reduce node overhead by up to one-third.
Instead of the small incremental rebalancing operations used by most balanced tree algorithms, scapegoat trees rarely but expensively choose a "scapegoat" and completely rebuild the subtree rooted at the scapegoat into a complete binary tree. Thus, scapegoat trees have worst-case update performance.
Theory
A binary search tree is said to be weight-balanced if half the nodes are on the left of the root, and half on the right.
An α-weight-balanced node is defined as meeting a relaxed weight balance criterion:
size(left) ≤ α*size(node)
size(right) ≤ α*size(node)
Where size can be defined recursively as:
function size(node) is
if node = nil then
return 0
else
return size(node->left) + size(node->right) + 1
end if
end function
Even a degenerate tree (linked list)
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https://en.wikipedia.org/wiki/Edouard%20Zeckendorf
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Edouard Zeckendorf (2 May 1901 – 16 May 1983) was a Belgian doctor, army officer and amateur mathematician. In mathematics, he is best known for his work on Fibonacci numbers and in particular for proving Zeckendorf's theorem, though he published over 20 papers, mostly in number theory.
Zeckendorf was born in Liège in 1901. He was the son of Abraham Zeckendorf, Dutch dentist and practicing Jew. In 1925, Zeckendorf graduated as a medical doctor from the University of Liège and joined the Belgian Army medical corps. When Germany invaded Belgium in 1940, Zeckendorf was taken prisoner and remained a prisoner of war until 1945. During this period, he provided medical care to other allied POWs.
Zeckendorf retired from the army in 1957 as a colonel.
References
20th-century Belgian mathematicians
1901 births
1983 deaths
University of Liège alumni
Physicians from Liège
Belgian military personnel of World War II
Belgian prisoners of war in World War II
Amateur mathematicians
Belgian people of Dutch descent
People of Dutch-Jewish descent
Jewish physicians
Belgian Army officers
World War II prisoners of war held by Germany
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https://en.wikipedia.org/wiki/Zeckendorf%27s%20theorem
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In mathematics, Zeckendorf's theorem, named after Belgian amateur mathematician Edouard Zeckendorf, is a theorem about the representation of integers as sums of Fibonacci numbers.
Zeckendorf's theorem states that every positive integer can be represented uniquely as the sum of one or more distinct Fibonacci numbers in such a way that the sum does not include any two consecutive Fibonacci numbers. More precisely, if is any positive integer, there exist positive integers , with , such that
where is the th Fibonacci number. Such a sum is called the Zeckendorf representation of . The Fibonacci coding of can be derived from its Zeckendorf representation.
For example, the Zeckendorf representation of 64 is
.
There are other ways of representing 64 as the sum of Fibonacci numbers
but these are not Zeckendorf representations because 34 and 21 are consecutive Fibonacci numbers, as are 5 and 3.
For any given positive integer, its Zeckendorf representation can be found by using a greedy algorithm, choosing the largest possible Fibonacci number at each stage.
History
While the theorem is named after the eponymous author who published his paper in 1972, the same result had been published 20 years earlier by Gerrit Lekkerkerker. As such, the theorem is an example of Stigler's Law of Eponymy.
Proof
Zeckendorf's theorem has two parts:
Existence: every positive integer has a Zeckendorf representation.
Uniqueness: no positive integer has two different Zeckendorf repres
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https://en.wikipedia.org/wiki/EBIT
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EBIT, Ebit or ebit may refer to:
EBIT, or Earnings before interest and taxes, in finance
EBIT, or Electron beam ion trap, in physics
An ebit (quantum state), a two-party quantum state with quantum entanglement and the fundamental unit of bipartite entanglement
Exabit, the symbol for the decimal unit of information storage
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https://en.wikipedia.org/wiki/Mesylate
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In organosulfur chemistry, a mesylate is any salt or ester of methanesulfonic acid (). In salts, the mesylate is present as the anion. When modifying the international nonproprietary name of a pharmaceutical substance containing the group or anion, the spelling used is sometimes mesilate (as in imatinib mesilate, the mesylate salt of imatinib).
Mesylate esters are a group of organic compounds that share a common functional group with the general structure , abbreviated , where R is an organic substituent. Mesylate is considered a leaving group in nucleophilic substitution reactions.
Preparation
Mesylates are generally prepared by treating an alcohol and methanesulfonyl chloride in the presence of a base, such as triethylamine.
Mesyl
Related to mesylate is the mesyl (Ms) or methanesulfonyl (CH3SO2) functional group. Methanesulfonyl chloride is often referred to as mesyl chloride. Whereas mesylates are often hydrolytically labile, mesyl groups, when attached to nitrogen, are resistant to hydrolysis. This functional group appears in a variety of medications, particularly cardiac (antiarrhythmic) drugs, as a sulfonamide moiety. Examples include sotalol, ibutilide, sematilide, dronedarone, dofetilide, E-4031, and bitopertin.
Natural occurrence
Ice core samples from a single spot in Antarctica were found to have tiny inclusions of magnesium methanesulfonate dodecahydrate. This natural phase is recognized as the mineral ernstburkeite. It is extremely rare.
See also
Tosylate
T
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https://en.wikipedia.org/wiki/Covering%20group
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In mathematics, a covering group of a topological group H is a covering space G of H such that G is a topological group and the covering map is a continuous group homomorphism. The map p is called the covering homomorphism. A frequently occurring case is a double covering group, a topological double cover in which H has index 2 in G; examples include the spin groups, pin groups, and metaplectic groups.
Roughly explained, saying that for example the metaplectic group Mp2n is a double cover of the symplectic group Sp2n means that there are always two elements in the metaplectic group representing one element in the symplectic group.
Properties
Let G be a covering group of H. The kernel K of the covering homomorphism is just the fiber over the identity in H and is a discrete normal subgroup of G. The kernel K is closed in G if and only if G is Hausdorff (and if and only if H is Hausdorff). Going in the other direction, if G is any topological group and K is a discrete normal subgroup of G then the quotient map p : G → G/K is a covering homomorphism.
If G is connected then K, being a discrete normal subgroup, necessarily lies in the center of G and is therefore abelian. In this case, the center of H = G/K is given by
As with all covering spaces, the fundamental group of G injects into the fundamental group of H. Since the fundamental group of a topological group is always abelian, every covering group is a normal covering space. In particular, if G is path-connected then th
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https://en.wikipedia.org/wiki/Efflorescence
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In chemistry, efflorescence (which means "to flower out" in French) is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or occasionally in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt.
In what has been described as "primary efflorescence", the water is the invader and the salt was already present internally, and a reverse process, where the salt is originally present externally and is then carried inside in solution, is referred to as "secondary efflorescence".
Efflorescences can occur in natural and built environments. On porous construction materials it may present a cosmetic outer problem only (primary efflorescence causing staining), but can sometimes indicate internal structural weakness (migration/degradation of component materials). Efflorescence may clog the pores of porous materials, resulting in the destruction of those materials by internal water pressure, as seen in the spalling of brick.
Examples
A 5 molar concentration aqueous droplet of NaCl will spontaneously crystallize at 45% relative humidity (298 K) to form an NaCl cube by the mechanism of homogeneous nucleation. The original water is released to the gas phase.
Gypsum (CaSO4.2H2O) is a hydrate solid that, in a sufficiently dry environment, will give up its water to the gas phase and form anhy
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https://en.wikipedia.org/wiki/Musical%20acoustics
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Musical acoustics or music acoustics is a multidisciplinary field that combines knowledge from physics, psychophysics, organology (classification of the instruments), physiology, music theory, ethnomusicology, signal processing and instrument building, among other disciplines. As a branch of acoustics, it is concerned with researching and describing the physics of music – how sounds are employed to make music. Examples of areas of study are the function of musical instruments, the human voice (the physics of speech and singing), computer analysis of melody, and in the clinical use of music in music therapy.
The pioneer of music acoustics was Hermann von Helmholtz, a German polymath of the 19th century who was an influential physician, physicist, physiologist, musician, mathematician and philosopher. His book On the Sensations of Tone as a Physiological Basis for the Theory of Music is a revolutionary compendium of several studies and approaches that provided a complete new perspective to music theory, musical performance, music psychology and the physical behaviour of musical instruments.
Methods and fields of study
The physics of musical instruments
Frequency range of music
Fourier analysis
Computer analysis of musical structure
Synthesis of musical sounds
Music cognition, based on physics (also known as psychoacoustics)
Physical aspects
Whenever two different pitches are played at the same time, their sound waves interact with each other – the highs and lows in the
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https://en.wikipedia.org/wiki/Tad%20Murty
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Tad S. Murty (or Murthy) is an Indian-Canadian oceanographer and expert on tsunamis. He is the former president of the Tsunami Society. He is an adjunct professor in the departments of Civil Engineering and Earth Sciences at the University of Ottawa. Murty has a PhD degree in oceanography and meteorology from the University of Chicago.
He is co-editor of the journal Natural Hazards with Tom Beer of CSIRO and Vladimir Schenk of the Czech Republic.
Climate change
He has taken part in a review of the 2007 Intergovernmental Panel on Climate Change.
Murty characterizes himself as a global warming skeptic. In an August 17, 2006 interview, he stated that "I started with a firm belief about global warming, until I started working on it myself...I switched to the other side in the early 1990s when Fisheries and Oceans Canada asked me to prepare a position paper and I started to look into the problem seriously.". Murty has also stated that global warming is "the biggest scientific hoax being perpetrated on humanity. There is no global warming due to human anthropogenic activities." Murty was among the sixty scientists from climate research and related disciplines who authored a 2006 open letter to Canadian Prime Minister Stephen Harper criticizing the Kyoto Protocol and the scientific basis of anthropogenic global warming.
References
External links
Indo-Canada Award
Canadian oceanographers
Indian oceanographers
Indian emigrants to Canada
University of Chicago alumni
Living pe
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https://en.wikipedia.org/wiki/Coal%20gasification
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In industrial chemistry, coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen (), carbon dioxide (), methane (), and water vapour ()—from coal and water, air and/or oxygen.
Historically, coal was gasified to produce coal gas, also known as "town gas". Coal gas is combustible and was used for heating and municipal lighting, before the advent of large-scale extraction of natural gas from oil wells.
In current practice, large-scale coal gasification installations are primarily for electricity generation (both in conventional thermal power stations and molten carbonate fuel cell power stations), or for production of chemical feedstocks. The hydrogen obtained from coal gasification can be used for various purposes such as making ammonia, powering a hydrogen economy, or upgrading fossil fuels.
Alternatively, coal-derived syngas can be converted into transportation fuels such as gasoline and diesel through additional treatment, or into methanol which itself can be used as transportation fuel or fuel additive, or which can be converted into gasoline.
Natural gas from coal gasification can be cooled until it liquifies for use as a fuel in the transport sector.
History
In the past, coal was converted to make coal gas, which was piped to customers to burn for illumination, heating, and cooking. High prices of oil and natural gas led to increased interest in "BTU Conversion" technologies such as gasification, methanat
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https://en.wikipedia.org/wiki/Cache%20coloring
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In computer science, cache coloring (also known as page coloring) is the process of attempting to allocate free pages that are contiguous from the CPU cache's point of view, in order to maximize the total number of pages cached by the processor. Cache coloring is typically employed by low-level dynamic memory allocation code in the operating system, when mapping virtual memory to physical memory. A virtual memory subsystem that lacks cache coloring is less deterministic with regards to cache performance, as differences in page allocation from one program run to the next can lead to large differences in program performance.
Details of operations
A physically indexed CPU cache is designed such that addresses in adjacent physical memory blocks take different positions ("cache lines") in the cache, but this is not the case when it comes to virtual memory; when virtually adjacent but not physically adjacent memory blocks are allocated, they could potentially both take the same position in the cache. Coloring is a technique implemented in memory management software, which solves this problem by selecting pages that do not contend with neighbor pages.
Physical memory pages are "colored" so that pages with different "colors" have different positions in CPU cache memory. When allocating sequential pages in virtual memory for processes, the kernel collects pages with different "colors" and maps them to the virtual memory. In this way, sequential pages in virtual memory do not conten
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https://en.wikipedia.org/wiki/Polyteichus
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Polyteichus is a genus of bryozoans of the order Trepostomata. They are spherical, semi-spherical or disc shaped, with 3 or 4 radiating lobes, being 2–5 cm in diameter. The zooecia are shaped as wide prisms.
Representatives of this genus have been found in the Upper Ordovician of the Czech Republic.
References
External links
Paleobiology database
Definition of zooecia
Trepostomata
Prehistoric bryozoan genera
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https://en.wikipedia.org/wiki/Time%20projection%20chamber
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In physics, a time projection chamber (TPC) is a type of particle detector that uses a combination of electric fields and magnetic fields together with a sensitive volume of gas or liquid to perform a three-dimensional reconstruction of a particle trajectory or interaction.
The original design
The original TPC was invented by David R. Nygren, an American physicist, at Lawrence Berkeley Laboratory in the late 1970s. Its first major application was in the PEP-4 detector, which studied 29 GeV electron–positron collisions at the PEP storage ring at SLAC.
A time projection chamber consists of a gas-filled detection volume in an electric field with a position-sensitive electron collection system. The original design (and the one most commonly used) is a cylindrical chamber with multi-wire proportional chambers (MWPC) as endplates. Along its length, the chamber is divided into halves by means of a central high-voltage electrode disc, which establishes an electric field between the center and the end plates. Furthermore, a magnetic field is often applied along the length of the cylinder, parallel to the electric field, in order to minimize the diffusion of the electrons coming from the ionization of the gas. On passing through the detector gas, a particle will produce primary ionization along its track. The z coordinate (along the cylinder axis) is determined by measuring the drift time from the ionization event to the MWPC at the end. This is done using the usual technique of a
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https://en.wikipedia.org/wiki/Susceptibility
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Susceptibility may refer to:
Physics and engineering
In physics the susceptibility is a quantification for the change of an extensive property under variation of an intensive property. The word may refer to:
In physics, the susceptibility of a material or substance describes its response to an applied field. For example:
Magnetic susceptibility
Electric susceptibility
The two types of susceptibility above are examples of a linear response function; sometimes the terms susceptibility and linear response function are used interchangeably.
In electromagnetic compatibility (EMC), susceptibility is the sensitivity of a device's function to incoming electromagnetic interference
Health and medicine
In epidemiology, a susceptible individual is a member of a population who is at risk of becoming infected by a disease
In microbiology, pharmacology, and medicine drug susceptibility is the ability of a microorganism to be inhibited or killed by the drug, as in antibiotic susceptibility, the susceptibility of microorganisms to antibiotics (often used synonymously with the lay term sensitivity)
Botany and environmental science
Susceptibility to pathogens is the extent to which a plant, vegetation complex, or ecological community would suffer from a pathogen if exposed, without regard to the likelihood of exposure the opposite of Plant disease resistance
It should not be confused with vulnerability, which by convention in this field takes into account both the effect of exposur
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https://en.wikipedia.org/wiki/Benjamin%20C.%20Pierce
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Benjamin Crawford Pierce is the Henry Salvatori Professor of computer science at the University of Pennsylvania. Pierce joined Penn in 1998 from Indiana University and held research positions at the University of Cambridge and the University of Edinburgh. He received his Ph.D. from Carnegie Mellon University in 1991. His research includes work on programming languages, static type systems, distributed programming, mobile agents, process calculi, and differential privacy.
As part of his research, Pierce has led development on several open-source software projects, including the Unison file synchronization utility.
In 2012 Pierce became an ACM Fellow for "contributions to the theory and practice of programming languages and their type systems". In 2015 Pierce and co-authors received the award for the most influential Principles of Programming Languages paper, which was described as "instrumental in bringing the view-update problem to the attention of the programming languages community and demonstrating the broad relevance of the problem beyond databases. [...] More broadly, the paper sparked a great deal of follow-on work in the area of BX (“bidirectional transformations”), leading to a fruitful collaboration between the worlds of databases, programming languages, and software engineering."
Books
He is the author of one book on type systems, Types and Programming Languages . He has also edited a collection of articles to create a second volume Advanced Topics in Types and
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https://en.wikipedia.org/wiki/Absorption%20%28chemistry%29
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In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, not by the surface (as in the case for adsorption).
A more common definition is that "Absorption is a chemical or physical phenomenon in which the molecules, atoms and ions of the substance getting absorbed enter into the bulk phase (gas, liquid or solid) of the material in which it is taken up."
A more general term is sorption, which covers absorption, adsorption, and ion exchange. Absorption is a condition in which something takes in another substance.
In many processes important in technology, the chemical absorption is used in place of the physical process, e.g., absorption of carbon dioxide by sodium hydroxide – such acid-base processes do not follow the Nernst partition law (see: solubility).
For some examples of this effect, see liquid-liquid extraction. It is possible to extract a solute from one liquid phase to another without a chemical reaction. Examples of such solutes are noble gases and osmium tetroxide.
The process of absorption means that a substance captures and transforms energy. The absorbent distributes the material it captures throughout whole and adsorbent only distributes it through the surface.
The process of gas or liquid which penetrate into the body of adsorbent is commonly kn
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https://en.wikipedia.org/wiki/Shin
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Shin may refer to:
Biology
The front part of the human leg below the knee
Shinbone, the tibia, the larger of the two bones in the leg below the knee in vertebrates
Names
Shin (given name) (Katakana: シン, Hiragana: しん), a Japanese given name
Shin (Korean surname) (Hangul: 신, Hanja: 申, 辛, 愼), a Korean family name
Shin (Chinese: 新, which means "new"), spelled in Pinyin as Xin
Fictional characters
Shin Akuma, a character in the Street Fighter series
Shin Asuka (disambiguation), multiple
Shin Malphur, a character in the video game Destiny 2: Forsaken
Kamen Rider Shin, a character in the Kamen Rider series
Seijuro Shin (進), a character in the manga and anime series Eyeshield 21
A character in the manga Dorohedoro
A character in the manga and anime Fist of the North Star
Shin Tsukimi from the video game Your Turn To Die
Music
Shin (band) ()
Shin (singer) (蘇見信), a Taiwanese singer and former lead singer of the band Shin
Shin, the drummer of the German visual kei group Cinema Bizarre
The Shin, a Georgian fusion jazz band
The Shins, an American indie band
Shin (シン), a Japanese rock singer and former vocalist of Vivid
Places
Shin, Iran, a village in Zanjan Province, Iran
Shin, Swat, an administrative unit in the Khyber Pakhtunkhwa province of Pakistan
Shin, Syria, a village in Syria
Loch Shin, a loch in the Scottish Highlands
River Shin, a river in the Scottish Highlands
Other uses
Shin (letter), the twenty-first letter in many Semitic alphabets, including He
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https://en.wikipedia.org/wiki/Absorption%20%28electromagnetic%20radiation%29
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In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy — and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy).
A notable effect of the absorption of electromagnetic radiation is attenuation of the radiation; attenuation is the gradual reduction of the intensity of light waves as they propagate through the medium.
Although the absorption of waves does not usually depend on their intensity (linear absorption), in certain conditions (optics) the medium's transparency changes by a factor that varies as a function of wave intensity, and saturable absorption (or nonlinear absorption) occurs.
Quantifying absorption
Many approaches can potentially quantify radiation absorption, with key examples following.
The absorption coefficient along with some closely related derived quantities
The attenuation coefficient (NB used infrequently with meaning synonymous with "absorption coefficient")
The Molar attenuation coefficient (also called "molar absorptivity"), which is the absorption coefficient divided by molarity (see also Beer–Lambert law)
The mass attenuation coefficient (also called "mass extinction coefficient"), which is the absorption coefficient divided by density
The absorption cross section and scattering cross-section, related closely to the absorption and attenuation coefficients, respectively
"Extinction" in astronomy, which is equivalen
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https://en.wikipedia.org/wiki/DTU%20Space
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The National Space Institute at the Technical University of Denmark, also known as DTU Space (), is a Danish sector research institute and a part of the Technical University of Denmark. It has a staff of 169, including researchers, engineers, and technicians.
The institute conducts research in astrophysics, Solar System physics, geodesy, and space technology. To conduct the research, the Institute collaborates with the Niels Bohr Institute for Astronomy, Geophysics and Physics.
It came about as a result of combining the Danish Space Research Institute with the geodesy part of the National Survey and Cadastre of Denmark on 1 January 2005 to form the Danish National Space Center (DNSC). In 2007, the DNSC merged with the Technical University of Denmark, and in 2008 changed its name to DTU Space.
The institute currently leads Swarm, a project to investigate the properties of the Earth's magnetic field.
See also
List of government space agencies
References
External links
Webpage (English version)
Research institutes in Denmark
National Space Center
Space agencies
Government agencies established in 2005
2005 establishments in Denmark
Geodesy organizations
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https://en.wikipedia.org/wiki/Character%20group
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In mathematics, a character group is the group of representations of a group by complex-valued functions. These functions can be thought of as one-dimensional matrix representations and so are special cases of the group characters that arise in the related context of character theory. Whenever a group is represented by matrices, the function defined by the trace of the matrices is called a character; however, these traces do not in general form a group. Some important properties of these one-dimensional characters apply to characters in general:
Characters are invariant on conjugacy classes.
The characters of irreducible representations are orthogonal.
The primary importance of the character group for finite abelian groups is in number theory, where it is used to construct Dirichlet characters. The character group of the cyclic group also appears in the theory of the discrete Fourier transform. For locally compact abelian groups, the character group (with an assumption of continuity) is central to Fourier analysis.
Preliminaries
Let be an abelian group. A function mapping the group to the non-zero complex numbers is called a character of if it is a group homomorphism from to —that is, if for all .
If is a character of a finite group , then each function value is a root of unity, since for each there exists such that , and hence .
Each character f is a constant on conjugacy classes of G, that is, f(hgh−1) = f(g). For this reason, a character is sometimes cal
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https://en.wikipedia.org/wiki/Michael%20S.%20Turner
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Michael S. Turner (born July 29, 1949) is an American theoretical cosmologist who coined the term dark energy in 1998.
He is the Rauner Distinguished Service Professor Emeritus of Physics at the University of Chicago, having previously served as the Bruce V. & Diana M. Rauner Distinguished Service Professor, and as the assistant director for Mathematical and Physical Sciences for the US National Science Foundation.
Turner's book The Early Universe, co-written with fellow Chicago cosmologist Edward Kolb, is a standard text on the subject.
The 2003 National Academy study, Connecting quarks with the cosmos: eleven science questions for the new century, which Turner chaired, identified opportunities at the intersection of astronomy and physics and has helped shape science investment in the US in this area.
In 2022, Turner was appointed as a co-leader, with Maria Spiropulu, of a National Academies of Science, Engineering and Medicine study, leading a committee of 17 physicists world-wide to consider the strategic vision of research in elementary particle physics.
Education
Turner received a B.S. in physics from the California Institute of Technology in 1971, and earned a PhD in physics from Stanford University in 1978.
Career
Turner became an instructor in physics at Stanford University in 1978, and was a fellow at the Enrico Fermi Institute from 1978 to 1980. He was a visiting professor at the Institute for Theoretical Physics at the University of California, Santa Barbara f
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https://en.wikipedia.org/wiki/Silvio%20Micali
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Silvio Micali (born October 13, 1954) is an Italian computer scientist, professor at the Massachusetts Institute of Technology and the founder of Algorand, a proof-of-stake blockchain cryptocurrency protocol. Micali's research at the MIT Computer Science and Artificial Intelligence Laboratory centers on cryptography and information security.
In 2012, he received the Turing Award for his work in cryptography.
Personal life
Micali graduated in mathematics at La Sapienza University of Rome in 1978 and earned a PhD degree in computer science from the University of California, Berkeley in 1982; for research supervised by Manuel Blum. Micali has been on the faculty at MIT, Electrical Engineering and Computer Science Department, since 1983. He's also served on the faculty of the University of Pennsylvania, University of Toronto, and Tsinghua University. His research interests are cryptography, zero knowledge, pseudorandom generation, secure protocols, and mechanism design.
Career
Micali is best known for some of his fundamental early work on public-key cryptosystems, pseudorandom functions, digital signatures, oblivious transfer, secure multiparty computation, and is one of the co-inventors of zero-knowledge proofs. His former doctoral students include Mihir Bellare, Bonnie Berger, Shai Halevi, Rafail Ostrovsky, Jing Chen, Rafael Pass, Chris Peikert, and Phillip Rogaway.
In 2001 Micali co-founded CoreStreet Ltd, a software company originally based in Cambridge, Massachusetts whi
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https://en.wikipedia.org/wiki/Rolf%20Landauer
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Rolf William Landauer (February 4, 1927 – April 27, 1999) was a German-American physicist who made important contributions in diverse areas of the thermodynamics of information processing, condensed matter physics, and the conductivity of disordered media. Born in Germany, he emigrated to the U.S. in 1938, obtained a Ph.D. in physics from Harvard in 1950, and then spent most of his career at IBM.
In 1961 he discovered Landauer's principle, that in any logically irreversible operation that manipulates information, such as erasing a bit of memory, entropy increases and an associated amount of energy is dissipated as heat. This principle is relevant to reversible computing, quantum information and quantum computing. He also is responsible for the Landauer formula relating the electrical resistance of a conductor to its scattering properties. He won the Stuart Ballantine Medal of the Franklin Institute, the Oliver Buckley Prize of the American Physical Society and the IEEE Edison Medal, among many other honors.
Biography
Landauer was born on February 4, 1927, in Stuttgart, Germany. He emigrated to the United States in 1938 to escape Nazi persecution of Jews, graduated in 1943 from Stuyvesant High School, one of New York City's mathematics and science magnet schools, and obtained his undergraduate degree from Harvard in 1945. Following service in the US Navy as an Electrician's Mate, he earned his Ph.D. from Harvard in 1950.
He first worked for two years at NASA, then known
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https://en.wikipedia.org/wiki/Dongyang%20Mirae%20University
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Dongyang Mirae University (formerly Dongyang Technical College) is an industrial technical university in Seoul, South Korea. Its campus is in the city's Guro-gu district. The current president is Han In-seung (한인승). More than 105 instructors are employed.
Academics
School of Mechanical Engineering
Department of Robotics and Automation Engineering
Department of Electrical and Electronic Communication Engineering
Department of Computer Science and Engineering
Department of Environmental Engineering
Faculty of Business Administration
You can visit the official link for more information https://www.dongyang.ac.kr/sites/dongyang/intro/index.html
History
The college opened in 1965 as Dongyang Advanced Industrial Technical School (Hangul: 동양공업고등전문학교).
See also
Education in South Korea
List of colleges and universities in South Korea
External links
Dongyang Mirae University Homepage, in English
Vocational education in South Korea
Universities and colleges in Seoul
Educational institutions established in 1965
1965 establishments in South Korea
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https://en.wikipedia.org/wiki/Max%20Planck%20Institute%20for%20Mathematics
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The Max Planck Institute for Mathematics (, MPIM) is a prestigious research institute located in Bonn, Germany. It is named in honor of the German physicist Max Planck
and forms part of the Max Planck Society (Max-Planck-Gesellschaft), an association of 84 institutes engaging in fundamental research in the arts and the sciences. The MPIM is the only Max Planck institute specializing in pure mathematics.
The Institute was founded by Friedrich Hirzebruch in 1980, having emerged from the collaborative research center "Theoretical Mathematics" (Sonderforschungsbereich "Theoretische Mathematik"). Hirzebruch shaped the institute as its director until his retirement in 1995. Currently, the institute is managed by a board of five directors consisting of Peter Teichner (managing director), Werner Ballmann, Gerd Faltings, Peter Scholze, and Don Zagier. Friedrich Hirzebruch and Yuri Manin were, and Günter Harder is, acting as emeriti.
Research
The Max Planck Institute for Mathematics offers mathematicians from around the world the opportunity to visit Bonn and engage in sabbatical work lasting from weeks to several months.
This guest program distinguishes the MPIM from other Max Planck institutes, and results in only a limit number of permanent positions and the absence of separate departments within the institute.
The research of the members and guests of the institute can be classified into the following areas:
Algebraic Geometry and Complex Geometry
Algebraic Groups
Algeb
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https://en.wikipedia.org/wiki/George%20Radda
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Sir George Charles Radda (; born 9 June 1936) is a Hungarian - British chemist. In 1957, he attended Merton College, Oxford, to study chemistry, having set aside an earlier interest in literary criticism. His early work was concerned with the development and use of fluorescent probes for the study of structure and function of membranes and enzymes. He became interested in using spectroscopic methods including nuclear magnetic resonance (NMR) to study complex biological material. In 1974, his research paper was the first to introduce the use of NMR to study tissue metabolites. In 1981, he and his colleagues published the first scientific report on the clinical application of his work. This resulted in the installation of a magnet large enough to accommodate the whole human body for NMR investigations in 1983 at the John Radcliffe Hospital in Oxford.
In 1982, Radda published about the relationship between deoxygenated haemoglobin and the NMR signal.
From 1996, until his retirement in 2004, Sir George was Chief Executive of the Medical Research Council in the UK.
Awards
He has received numerous prestigious awards and honours for his pioneering efforts in using spectroscopic techniques for metabolic studies, including a Buchanan Medal in 1987, an CBE in June 1993 and a knighthood in June 2000. He is a Fellow of Merton College, Oxford, a Fellow of the Royal Society and is a British Heart Foundation Professor of Molecular Cardiology. He has also been awarded many distinguishe
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https://en.wikipedia.org/wiki/Mark%20Welland
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Sir Mark Edward Welland, (born 18 October 1955) is a British physicist who is a professor of nanotechnology at the University of Cambridge and head of the Nanoscience Centre. He has been a fellow of St John's College, Cambridge, since 1986 and started his career in nanotechnology at IBM Research, where he was part of the team that developed one of the first scanning tunnelling microscopes. He was served as the Master of St Catharine's College, Cambridge and took up office from 2016 to 2023.
Early life and education
Welland was born on 18 October 1955. He completed a Bachelor of Science (BSc) degree in physics from the University of Leeds in 1979 and Master of Science and Doctor of Philosophy (PhD) degree in physics from the University of Bristol in 1984 for research on grain boundaries.
Career
Welland moved to Cambridge in 1987 and set up the first tunnelling microscopy group in the UK in collaboration with John Pethica. Currently at the Nanoscience Centre at the University of Cambridge researches into a number of aspects of nanotechnology ranging from sensors for medical applications to understanding and controlling the properties of nanoscale structures and devices.
In a recent award by the UK Research Councils, Welland has been made Director of an Interdisciplinary Research Collaboration in nanotechnology that, along with a purpose-built facility, represents an investment of $28 million for nanotechnology research at Cambridge. Until 2008, he was Editor-in-Chief of the
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https://en.wikipedia.org/wiki/Shake%20%28unit%29
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A shake is an informal metric unit of time equal to 10 nanoseconds, or 10−8 seconds. It was originally coined for use in nuclear physics, helping to conveniently express the timing of various events in a nuclear reaction, especially neutron reactions.
Etymology
Like many informal units having to do with nuclear physics, it arose from top secret operations of the Manhattan Project during World War II. The word "shake" was taken from the idiomatic expression "in two shakes of a lamb's tail", which indicates a very short time interval.
Lexicographers have discussed at length that the oldest documented usage of the phrase "two shakes of a lamb's tail" found first (so far) in the works of Richard Barham ; however, the phrase almost certainly was part of vernacular language long before then.
Nuclear physics
For nuclear-bomb designers, the term was a convenient name for the short interval, rounded to 10 nanoseconds, which was frequently seen in their measurements and calculations:
The typical time required for one step in a chain reaction (i.e. the typical time for each neutron to cause a fission event, which releases more neutrons) is of the order of 1 shake, and a chain reaction is typically complete by 50 to 100 shakes.
Integrated circuitry
Shakes are also applicable to circuits. Since signal progression in IC chips is very rapid, on the order of nanoseconds, a shake is good measure of how quickly a signal can progress through an integrated circuit (IC).
See also
‘Barn’ a
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https://en.wikipedia.org/wiki/Gaussian%20noise
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In signal processing theory, Gaussian noise, named after Carl Friedrich Gauss, is a kind of signal noise that has a probability density function (pdf) equal to that of the normal distribution (which is also known as the Gaussian distribution). In other words, the values that the noise can take are Gaussian-distributed.
The probability density function of a Gaussian random variable is given by:
where represents the grey level, the mean grey value and its standard deviation.
A special case is white Gaussian noise, in which the values at any pair of times are identically distributed and statistically independent (and hence uncorrelated). In communication channel testing and modelling, Gaussian noise is used as additive white noise to generate additive white Gaussian noise.
In telecommunications and computer networking, communication channels can be affected by wideband Gaussian noise coming from many natural sources, such as the thermal vibrations of atoms in conductors (referred to as thermal noise or Johnson–Nyquist noise), shot noise, black-body radiation from the earth and other warm objects, and from celestial sources such as the Sun.
Gaussian noise in digital images
Principal sources of Gaussian noise in digital images arise during acquisition e.g. sensor noise caused by poor illumination and/or high temperature, and/or transmission e.g. electronic circuit noise. In digital image processing Gaussian noise can be reduced using a spatial filter, though when
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https://en.wikipedia.org/wiki/System%20of%20imprimitivity
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The concept of system of imprimitivity is used in mathematics, particularly in algebra and analysis, both within the context of the theory of group representations. It was used by George Mackey as the basis for his theory of induced unitary representations of locally compact groups.
The simplest case, and the context in which the idea was first noticed, is that of finite groups (see primitive permutation group). Consider a group G and subgroups H and K, with K contained in H. Then the left cosets of H in G are each the union of left cosets of K. Not only that, but translation (on one side) by any element g of G respects this decomposition. The connection with induced representations is that the permutation representation on cosets is the special case of induced representation, in which a representation is induced from a trivial representation. The structure, combinatorial in this case, respected by translation shows that either K is a maximal subgroup of G, or there is a system of imprimitivity (roughly, a lack of full "mixing"). In order to generalise this to other cases, the concept is re-expressed: first in terms of functions on G constant on K-cosets, and then in terms of projection operators (for example the averaging over K-cosets of elements of the group algebra).
Mackey also used the idea for his explication of quantization theory based on preservation of relativity groups acting on configuration space. This generalized work of Eugene Wigner and others and is often
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https://en.wikipedia.org/wiki/Gilbert%20Walker%20%28physicist%29
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Sir Gilbert Thomas Walker (14 June 1868 – 4 November 1958) was an English physicist and statistician of the 20th century. Walker studied mathematics and applied it to a variety of fields including aerodynamics, electromagnetism and the analysis of time-series data before taking up a teaching position at the University of Cambridge. Although he had no experience in meteorology, he was recruited for a post in the Indian Meteorological Department where he worked on statistical approaches to predict the monsoons. He developed the methods in the analysis of time-series data that are now called the Yule-Walker equations. He is known for his groundbreaking description of the Southern Oscillation, a major phenomenon of global climate, and for discovering what is named after him as the Walker circulation, and for greatly advancing the study of climate in general. He was also instrumental in aiding the early career of the Indian mathematical prodigy, Srinivasa Ramanujan.
Early life and education
Walker was born in Rochdale, Lancashire on 14 June 1868, the fourth child and eldest son of Thomas Walker and Elizabeth Charlotte Haslehurst. Thomas was Borough Engineer of Croydon and had pioneered the use of concrete for town reservoirs. He attended Whitgift School where he showed an interest in mathematics and got a scholarship to study at St Paul's School. He attended Trinity College, Cambridge where he was Senior Wrangler in 1889. His hard studies led to ill-health and he spent several w
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https://en.wikipedia.org/wiki/Hybridization%20probe
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In molecular biology, a hybridization probe (HP) is a fragment of DNA or RNA of usually 15–10000 nucleotide long which can be radioactively or fluorescently labeled. HP can be used to detect the presence of nucleotide sequences in analyzed RNA or DNA that are complementary to the sequence in the probe. The labeled probe is first denatured (by heating or under alkaline conditions such as exposure to sodium hydroxide) into single stranded DNA (ssDNA) and then hybridized to the target ssDNA (Southern blotting) or RNA (northern blotting) immobilized on a membrane or in situ.
To detect hybridization of the probe to its target sequence, the probe is tagged (or "labeled") with a molecular marker of either radioactive or (more recently) fluorescent molecules. Commonly used markers are 32P (a radioactive isotope of phosphorus incorporated into the phosphodiester bond in the probe DNA), digoxigenin, a non-radioactive, antibody-based marker, biotin or fluorescein. DNA sequences or RNA transcripts that have moderate to high sequence similarity to the probe are then detected by visualizing the hybridized probe via autoradiography or other imaging techniques. Normally, either X-ray pictures are taken of the filter, or the filter is placed under UV light. Detection of sequences with moderate or high similarity depends on how stringent the hybridization conditions were applied—high stringency, such as high hybridization temperature and low salt in hybridization buffers, permits only hybri
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https://en.wikipedia.org/wiki/Solvent%20cabinet
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In a chemistry laboratory a solvent cabinet is a chemical storage cabinet or cupboard which is properly labeled and equipped, for the storage of solvents (especially those that are combustible). A solvent cabinet should be positioned separately from acid cabinet or base cabinet (used for storing acids and caustic bases respectively, as solvents are not compatible with these substances. (Some carts for transporting containers of chemicals come equipped with a built in solvent cabinet).
A solvent cabinet must incorporate a number of safety features. It should be adequately ventilated, preventing the release of excessive fumes (being either sealed or vented). It should be equipped to contain fires and isolate the contents from sources of ignition, be grounded (to prevent sparks and static discharge).
References
Laboratory equipment
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https://en.wikipedia.org/wiki/Watch%20glass
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A watch glass is a circular concave piece of glass used in chemistry as a surface to evaporate a liquid, to hold solids while being weighed, for heating a small amount of substance, and as a cover for a beaker. When used to cover beakers, the purpose is generally to prevent dust or other particles from entering the beaker; the watch glass does not completely seal the beaker, so gas exchanges still occur. When used as an evaporation surface, a watch glass allows closer observation of precipitates or crystallization. It can be placed on a surface of contrasting colors to improve the visibility overall. Watch glasses are also sometimes used to cover a glass of whisky, to concentrate the aromas in the glass, and to prevent spills when the whisky is swirled. Watch glasses are named so because they are similar to the glass used for the front of old-fashioned pocket watches. These large watch glasses are occasionally known as clock glasses.
Uses
One of the generic uses of a watch glass is as a lid for beakers. In this case, a watch glass is placed above the container, which makes it easier to control and alter vapor saturation conditions. Moreover, a watch glass is often used to house solids being weighed on the scale. Before weighing desired amount of solid, a watch glass is placed on the scale, followed by taring or zeroing the scale so that only the weight of the sample substance is obtained. A watch glass can also be used for observing precipitation and crystallization patte
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https://en.wikipedia.org/wiki/Cork%20borer
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A cork borer, often used in a chemistry or biology laboratory, is a metal tool for cutting a hole in a cork or rubber stopper to insert glass tubing. Cork borers usually come in a set of nested sizes along with a solid pin for pushing the removed cork (or rubber) out of the borer. The individual borer is a hollow tube, tapered at the edge, generally with some kind of handle at the other end.
A separate device is a cork borer sharpener used to hone the cutting edge to more easily slice the cork.
Cork borers are also used to take samples from living trees, for tree ring analysis (dendrochronology), and for taking samples for experiments when a constant diameter is required, e.g. When testing the water potential of a potato, a cork borer is used to maintain a constant surface area.
A cork borer is also used to punch holes on an agar plate and to perform well diffusion assays in microbiology to study bioactivity.
References
Laboratory equipment
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https://en.wikipedia.org/wiki/C.%20C.%20Li
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In this Chinese name, the family name is Li (李).
Ching Chun Li (; October 27, 1912 – October 20, 2003) was a Chinese-American population geneticist and human geneticist. He was known for his research and the book An Introduction to Population Genetics.
Biography
Ching Chun Li was born on October 27, 1912, in Taku (Chinese: 大沽口), Tianjin, China. He received his BS degree in agronomy from the University of Nanking in 1936 and a PhD in plant breeding and genetics from Cornell University in 1940. He worked as post-doctorate fellows at Columbia University and North Carolina State University from 1940 to 1941.
Li returned to China at the age of 30 and became the Professor of Genetics and Biometry at University of Nanking, his alma mater, in 1943. After World War II, he moved to Beijing for a Professorship and dean of Agronomy at Peking University in 1946, where he finished An Introduction to Population Genetics in 1948. The book was the first notable publication where a combination of the ideas of Ronald Fisher, Sewall Wright, and J. B. S. Haldane about population genetics was brought to and made understandable to the academia.
Li became persona non grata for publishing and teaching theory of genes following the 1949 establishment of a Communist government in Mainland China. The new government took the diplomatic policy of "Leaning to One Side" and adopted Soviet thought and action, including the genetic thought of the Soviet pseudoscientist Trofim Lysenko, who was standing ag
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https://en.wikipedia.org/wiki/Transactions%20of%20the%20American%20Mathematical%20Society
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The Transactions of the American Mathematical Society is a monthly peer-reviewed scientific journal of mathematics published by the American Mathematical Society. It was established in 1900. As a requirement, all articles must be more than 15 printed pages.
See also
Bulletin of the American Mathematical Society
Journal of the American Mathematical Society
Memoirs of the American Mathematical Society
Notices of the American Mathematical Society
Proceedings of the American Mathematical Society
External links
Transactions of the American Mathematical Society on JSTOR
American Mathematical Society academic journals
Mathematics journals
Publications established in 1900
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https://en.wikipedia.org/wiki/Gas%20in%20a%20box
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In quantum mechanics, the results of the quantum particle in a box can be used to look at the equilibrium situation for a quantum ideal gas in a box which is a box containing a large number of molecules which do not interact with each other except for instantaneous thermalizing collisions. This simple model can be used to describe the classical ideal gas as well as the various quantum ideal gases such as the ideal massive Fermi gas, the ideal massive Bose gas as well as black body radiation (photon gas) which may be treated as a massless Bose gas, in which thermalization is usually assumed to be facilitated by the interaction of the photons with an equilibrated mass.
Using the results from either Maxwell–Boltzmann statistics, Bose–Einstein statistics or Fermi–Dirac statistics, and considering the limit of a very large box, the Thomas–Fermi approximation (named after Enrico Fermi and Llewellyn Thomas) is used to express the degeneracy of the energy states as a differential, and summations over states as integrals. This enables thermodynamic properties of the gas to be calculated with the use of the partition function or the grand partition function. These results will be applied to both massive and massless particles. More complete calculations will be left to separate articles, but some simple examples will be given in this article.
Thomas–Fermi approximation for the degeneracy of states
For both massive and massless particles in a box, the states of a particle are
enumera
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https://en.wikipedia.org/wiki/Subdivision
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Subdivision may refer to:
Arts and entertainment
Subdivision (metre), in music
Subdivision (film), 2009
"Subdivision", an episode of Prison Break (season 2)
Subdivisions (EP), by Sinch, 2005
"Subdivisions" (song), by Rush, 1982
Science, technology and mathematics
Subdivision (rank), a taxonomic rank
Subdivision (botany), or subphylum, a taxonomic rank
Subdivision, resulting in Homeomorphism (graph theory)
Subdivision surface, in computer graphics
Other uses
Subdivision, an administrative division, a portion of a country
Subdivision (India), an administrative division in India
Subdivision (land), the act of dividing land into smaller pieces
See also
Division (disambiguation)
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https://en.wikipedia.org/wiki/Sternenbote
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The Sternenbote is a monthly scientific journal on astronomy published by the Astronomisches Büro (Vienna). It was established in 1958, and contents include ephemerides of comets and other Solar System objects and observation reports. It is abstracted and indexed in the Astrophysics Data System.
External links
Planetary science journals
German-language journals
Academic journals established in 1958
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https://en.wikipedia.org/wiki/Loop%20group
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In mathematics, a loop group is a group of loops in a topological group G with multiplication defined pointwise.
Definition
In its most general form a loop group is a group of continuous mappings from a manifold to a topological group .
More specifically, let , the circle in the complex plane, and let denote the space of continuous maps , i.e.
equipped with the compact-open topology. An element of is called a loop in .
Pointwise multiplication of such loops gives the structure of a topological group. Parametrize with ,
and define multiplication in by
Associativity follows from associativity in . The inverse is given by
and the identity by
The space is called the free loop group on . A loop group is any subgroup of the free loop group .
Examples
An important example of a loop group is the group
of based loops on . It is defined to be the kernel of the evaluation map
,
and hence is a closed normal subgroup of . (Here, is the map that sends a loop to its value at .) Note that we may embed into as the subgroup of constant loops. Consequently, we arrive at a split exact sequence
.
The space splits as a semi-direct product,
.
We may also think of as the loop space on . From this point of view, is an H-space with respect to concatenation of loops. On the face of it, this seems to provide with two very different product maps. However, it can be shown that concatenation and pointwise multiplication are homotopic. Thus, in terms of the homotopy theory
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https://en.wikipedia.org/wiki/Nanomotor
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A nanomotor is a molecular or nanoscale device capable of converting energy into movement. It can typically generate forces on the order of piconewtons.
While nanoparticles have been utilized by artists for centuries, such as in the famous Lycurgus cup, scientific research into nanotechnology did not come about until recently. In 1959, Richard Feynman gave a famous talk entitled "There's Plenty of Room at the Bottom" at the American Physical Society's conference hosted at Caltech. He went on to wage a scientific bet that no one person could design a motor smaller than 400 µm on any side. The purpose of the bet (as with most scientific bets) was to inspire scientists to develop new technologies, and anyone who could develop a nanomotor could claim the $1,000 USD prize. However, his purpose was thwarted by William McLellan, who fabricated a nanomotor without developing new methods. Nonetheless, Richard Feynman's speech inspired a new generation of scientists to pursue research into nanotechnology.
Nanomotors are the focus of research for their ability to overcome microfluidic dynamics present at low Reynold's numbers. Scallop Theory explains that nanomotors must break symmetry to produce motion at low Reynold's numbers. In addition, Brownian motion must be considered because particle-solvent interaction can dramatically impact the ability of a nanomotor to traverse through a liquid. This can pose a significant problem when designing new nanomotors. Current nanomotor research
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https://en.wikipedia.org/wiki/Martin%20Cline
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Martin J. Cline (born 1934) is an American geneticist who is the Professor Emeritus of Medicine at the University of California, Los Angeles (UCLA). He did postdoctoral training in hematology-oncology at the University of Utah and was at the University of California, San Francisco before going to UCLA. His research has been in cell biology, molecular biology, and genetics.
Accomplishments
Cline was the first to successfully transfer a functioning gene into a living mouse, creating the first transgenic organism. His research has also pertained to the molecular genetic alterations in cancer, especially in leukemia.
In 1980, Cline conducted a rDNA transfer into the bone marrow cells of two patients with hereditary blood disorders. He did so in direct opposition to National Institute of Health gene therapy guidelines and without the approval of the Institutional Review Board at the University of California Los Angeles (UCLA), where his research was conducted. The ethical concerns that were generated prompted a call for review by a number of organizations—including the National Council of Churches, Synagogue Council of America, and the United States Catholic Conference. Consequently, Cline was forced to resign his department chairmanship at UCLA and lost several research grants.
References
Further reading
American geneticists
1934 births
Living people
University of Utah alumni
University of California, San Francisco faculty
David Geffen School of Medicine at UCLA faculty
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https://en.wikipedia.org/wiki/Ian%20McDonald%20%28British%20author%29
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Ian McDonald (born 1960) is a British science fiction novelist, living in Belfast. His themes include nanotechnology, postcyberpunk settings, and the impact of rapid social and technological change on non-Western societies.
Early life
Ian McDonald was born in 1960, in Manchester, to a Scottish father and Irish mother. He moved to Belfast when he was five and has lived there ever since. He lived through the whole of the 'Troubles' (1968–1999), and his sensibility has been permanently shaped by coming to understand Northern Ireland as a post-colonial society imposed on an older culture.
Career
McDonald sold his first story to a local Belfast magazine when he was 22, and in 1987 became a full-time writer. He has also worked in TV consultancy within Northern Ireland, contributing scripts to the Northern Irish Sesame Workshop production of Sesame Tree.
McDonald's debut novel was Desolation Road (1988), which takes place on a far future Mars in a town that develops around an oasis in the terraformed Martian desert. He published a sequel, Ares Express, in 2001.
Published between 1995 and 2000, the novels Chaga (US title Evolution's Shore) and Kirinya, with the novella Tendeléo's Story, form the 'Chaga Saga', which chronicles the effects of an alien flora introduced to Earth, and also analyses the AIDS crisis in Africa. The protagonist is Ulster journalist Gaby McAslin, whose outsider's eye both observes the African landscape and sees what the "UN quarantine zone" is doing to Ken
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https://en.wikipedia.org/wiki/DSI
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DSI may refer to:
Abbreviations
DontStayIn, a social networking website
Airport
IATA airport code for Destin Executive Airport
Businesses
DSI is an initialism for the following companies:
Daiichi Sankyo, Incorporated
Data Sciences International, a company in Saint Paul, United States
Dave Smith Instruments, an American synthesizer company
Deep Space Industries, American-based asteroid mining startup
Deep Springs International
Delphi Schools, Inc.
Delphine Software International, a now bankrupt software company
Destination Software, Inc., a video game company
Distinctive Software Inc., a video game company
Diversified Specialty Institute Holdings, Inc., a US-based healthcare group
Drivetrain Systems International, an Australian automotive transmissions manufacturer
DYWIDAG Systems International, an international supplier of ground anchors and post-tensioning systems
State Hydraulic Works (Turkey) (Turkish: Devlet Su İşleri (DSİ)), a state agency in Turkey
Education
Decision Sciences Institute, a professional association focusing on the application of quantitative research and qualitative research to the decision problems of individuals, organizations, and society.
Deutsche Schule Istanbul, a private high school in Istanbul
Gaming
Dead Space Ignition, a video game in the Dead Space series
Nintendo DSi, Nintendo's third iteration of the Nintendo DS handheld game console
Music
Dope Stars Inc., an industrial metal band formed in 2002
Organization
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https://en.wikipedia.org/wiki/Tree%20breeding
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Tree breeding is the application of genetic, reproductive biology and economics principles to the genetic improvement and management of forest trees. In contrast to the selective breeding of livestock, arable crops, and horticultural flowers over the last few centuries, the breeding of trees, with the exception of fruit trees, is a relatively recent occurrence.
A typical forest tree breeding program starts with selection of superior phenotypes (plus trees) in a natural or planted forest, often based on growth rate, tree form and site adaptation traits. This application of mass selection improves the mean performance of the forest. Offspring is obtained from selected trees and grown in test plantations that act as genetic trials. Based on such tests the best genotypes among the parents can be selected. Selected trees are typically multiplied by either seeds or grafting and seed orchards are established when the preferred output is improved seed. Alternatively, the best genotypes can be directly propagated by cuttings or in-vitro methods and used directly in clonal plantations. The first system is frequently used in pines and other conifers, while the second is typical in some broadleaves (poplars, eucalypts and others). The objectives of a tree breeding program range from yield improvement and adaptation to particular conditions, to pest- and disease-resistance, wood properties, etc. Currently, tree breeding is starting to take advantage of the fast development in plant genet
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https://en.wikipedia.org/wiki/Reflection%20symmetry
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In mathematics, reflection symmetry, line symmetry, mirror symmetry, or mirror-image symmetry is symmetry with respect to a reflection. That is, a figure which does not change upon undergoing a reflection has reflectional symmetry.
In 2D there is a line/axis of symmetry, in 3D a plane of symmetry. An object or figure which is indistinguishable from its transformed image is called mirror symmetric. In conclusion, a line of symmetry splits the shape in half and those halves should be identical.
Symmetric function
In formal terms, a mathematical object is symmetric with respect to a given operation such as reflection, rotation or translation, if, when applied to the object, this operation preserves some property of the object. The set of operations that preserve a given property of the object form a group. Two objects are symmetric to each other with respect to a given group of operations if one is obtained from the other by some of the operations (and vice versa).
The symmetric function of a two-dimensional figure is a line such that, for each perpendicular constructed, if the perpendicular intersects the figure at a distance 'd' from the axis along the perpendicular, then there exists another intersection of the shape and the perpendicular, at the same distance 'd' from the axis, in the opposite direction along the perpendicular.
Another way to think about the symmetric function is that if the shape were to be folded in half over the axis, the two halves would be identic
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https://en.wikipedia.org/wiki/Single%20bond
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In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond. When shared, each of the two electrons involved is no longer in the sole possession of the orbital in which it originated. Rather, both of the two electrons spend time in either of the orbitals which overlap in the bonding process. As a Lewis structure, a single bond is denoted as AːA or A-A, for which A represents an element. In the first rendition, each dot represents a shared electron, and in the second rendition, the bar represents both of the electrons shared in the single bond.
A covalent bond can also be a double bond or a triple bond. A single bond is weaker than either a double bond or a triple bond. This difference in strength can be explained by examining the component bonds of which each of these types of covalent bonds consists (Moore, Stanitski, and Jurs 393).
Usually, a single bond is a sigma bond. An exception is the bond in diboron, which is a pi bond. In contrast, the double bond consists of one sigma bond and one pi bond, and a triple bond consists of one sigma bond and two pi bonds (Moore, Stanitski, and Jurs 396). The number of component bonds is what determines the strength disparity. It stands to reason that the single bond is the weakest of the three because it consists of only a sigma bond, and the double bond or triple bond consist
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https://en.wikipedia.org/wiki/List%20of%20unsolved%20problems%20in%20neuroscience
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There are yet unsolved problems in neuroscience, although some of these problems have evidence supporting a hypothesized solution, and the field is rapidly evolving. One major problem is even enumerating what would belong on a list such as this. However, these problems include:
Consciousness
Consciousness:
How can consciousness be defined?
What is the neural basis of subjective experience, cognition, wakefulness, alertness, arousal, and attention?
Quantum mind: Does quantum mechanical phenomena, such as entanglement and superposition, play an important part in the brain's function and can it explain critical aspects of consciousness?
Is there a "hard problem of consciousness"?
If so, how is it solved?
What, if any, is the function of consciousness?
What is the nature and mechanism behind near-death experiences?
How can death be defined? Can consciousness exist after death?
If consciousness is generated by brain activity, then how do some patients with physically deteriorated brains suddenly gain a brief moment of restored consciousness prior to death, a phenomenon known as terminal lucidity?
Problem of representation: How exactly does the mind function (or how does the brain interpret and represent information about the world)?
Bayesian mind: Does the mind make sense of the world by constantly trying to make predictions according to the rules of Bayesian probability?
Computational theory of mind: Is the mind a symbol manipulation system, operating on a model of comput
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https://en.wikipedia.org/wiki/Control%20theory%20%28sociology%29
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Control theory in sociology is the idea that two control systems—inner controls and outer controls—work against our tendencies to deviate. Control theory can either be classified as centralized or decentralized. Decentralized control is considered market control. Centralized control is considered bureaucratic control. Some types of control such as clan control are considered to be a mixture of both decentralized and centralized control.
Decentralized control or market control is typically maintained through factors such as price, competition, or market share. Centralized control such as bureaucratic control is typically maintained through administrative or hierarchical techniques such as creating standards or policies. An example of mixed control is clan control which has characteristics of both centralized and decentralized control. Mixed control or clan control is typically maintained by keeping a set of values and beliefs or norms and traditions.
Containment theory, as developed by Walter Reckless in 1973, states that behavior is caused not by outside stimuli, but by what a person wants most at any given time. According to the control theory, weaker containing social systems result in more deviant behavior.
Control theory stresses how weak bonds between the individuals and society free people to deviate or go against the norms, or the people who have weak ties would engage in crimes so they could benefit, or gain something that is to their own interest. This is whe
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https://en.wikipedia.org/wiki/Richard%20Friend
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Sir Richard Henry Friend (born 18 January 1953) is a British physicist who was the Cavendish Professor of Physics at the University of Cambridge from 1995 until 2020 and is Tan Chin Tuan Centennial Professor at the National University of Singapore. Friend's research concerns the physics and engineering of carbon-based semiconductors. He also serves as Chairman of the Scientific Advisory Board of the National Research Foundation (NRF) of Singapore.
Education
Friend was educated at Rugby School and Trinity College, Cambridge, gaining a PhD in 1979 under the supervision of Abe Yoffe.
Research
Friend's research has been applied to development of polymer field effect transistors, light-emitting diodes, photovoltaic diodes, optically pumped lasing and directly printed polymer transistors. He pioneered the study of organic polymers and the electronic properties of molecular semiconductors. He is one of the principal investigators in the new Cambridge-based Interdisciplinary Research Collaboration (IRC) on nanotechnology and co-founder of Cambridge Display Technology (CDT) and Plastic Logic. Friend has co-authored over 1,000 publications.
Awards and honours
In March 2003 Friend won the IEE's Faraday Medal. He was knighted for "services to physics" in the 2003 Birthday Honours.
Friend received an Honorary Doctorate from Heriot-Watt University in 2006
In 2009, Friend was awarded the Institute of Physics Katharine Burr Blodgett Medal and Prize with Dr David Ffye.
In 2010, Friend
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https://en.wikipedia.org/wiki/Nob%20Yoshigahara
|
Nobuyuki Yoshigahara ( Yoshigahara Nobuyuki, commonly known as "Nob"; May 27, 1936 – June 19, 2004) was perhaps Japan's most celebrated inventor, collector, solver, and communicator of puzzles.
Nob graduated from the Tokyo Institute of Technology in applied chemistry. After becoming disenchanted with his career in high-polymer engineering, Nob turned to high school teaching as an educator of chemistry and mathematics.
As a puzzle columnist, Nob was an active contributor to many journals and had monthly columns in various popular magazines, including Quark. He penned over 80 books on puzzles. Perhaps best known as a puzzle inventor, he commercially licensed his designs, such as the Rush Hour puzzle game, to companies including Binary Arts (now known as ThinkFun), Ishi Press, and Hanayama. He was also an avid computer programmer who used computers to help solve mathematical puzzles.
Nob was an active participant in the International Puzzle Party, traveling the world to attend the annual event. In 2005, the puzzle design competition of the International Puzzle Parties was renamed the Nob Yoshigahara Puzzle Design Competition.
In 2003, the Association of Game & Puzzle Collectors awarded Nob with the Sam Loyd Award, given to individuals who have made a significant contribution to the world of mechanical puzzles.
See also
Puzzle
Mechanical puzzle
Kagen Sound
Nob Yoshigahara Puzzle Design Competition
References
External links
Ed Pegg Jr. Nob Yoshigahara, June 28, 2004.
Exam
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https://en.wikipedia.org/wiki/Handedness%20%28disambiguation%29
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Handedness is a human attribute reflecting the unequal distribution of fine motor skill between the left and right hands.
Handedness may also refer to:
Chirality, Greek for handedness, used to describe similar concepts in other fields:
Chirality (chemistry), a property of molecules having a non-superimposable mirror image
Chirality (electromagnetism), an electromagnetic propagation in chiral media
Chirality (mathematics), the property of a figure not being identical to its mirror image
Chirality (physics), when a phenomenon is not identical to its mirror image
Sinistral and dextral, terms in biology and geology
Orientation (vector space), an asymmetry that makes a reflection impossible to replicate by means of a simple rotation
Handedness of a helix, a spiral structure
Handedness of screw threads, springs, or propellers, in mechanics and engineering
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https://en.wikipedia.org/wiki/Catagenesis
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Catagenesis may refer to:
Catagenesis (geology), the cracking process in which organic kerogens are broken down into hydrocarbons
Catagenesis (biology), archaic term from evolutionary biology meaning retrogressive evolution, as contrasted with anagenesis
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https://en.wikipedia.org/wiki/Catagenesis%20%28biology%29
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Catagenesis is a somewhat archaic term from evolutionary biology referring to evolutionary directions that were considered "retrogressive." It was a term used in contrast to anagenesis, which in present usage denotes the evolution of a single population into a new form without branching lines of descent.
See also
Evolutionary biology
References
Evolutionary biology
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https://en.wikipedia.org/wiki/Stiefel%20manifold
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In mathematics, the Stiefel manifold is the set of all orthonormal k-frames in That is, it is the set of ordered orthonormal k-tuples of vectors in It is named after Swiss mathematician Eduard Stiefel. Likewise one can define the complex Stiefel manifold of orthonormal k-frames in and the quaternionic Stiefel manifold of orthonormal k-frames in . More generally, the construction applies to any real, complex, or quaternionic inner product space.
In some contexts, a non-compact Stiefel manifold is defined as the set of all linearly independent k-frames in or this is homotopy equivalent, as the compact Stiefel manifold is a deformation retract of the non-compact one, by Gram–Schmidt. Statements about the non-compact form correspond to those for the compact form, replacing the orthogonal group (or unitary or symplectic group) with the general linear group.
Topology
Let stand for or The Stiefel manifold can be thought of as a set of n × k matrices by writing a k-frame as a matrix of k column vectors in The orthonormality condition is expressed by A*A = where A* denotes the conjugate transpose of A and denotes the k × k identity matrix. We then have
The topology on is the subspace topology inherited from With this topology is a compact manifold whose dimension is given by
As a homogeneous space
Each of the Stiefel manifolds can be viewed as a homogeneous space for the action of a classical group in a natural manner.
Every orthogonal transformation of a k-fra
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https://en.wikipedia.org/wiki/Mu%20Alpha%20Theta
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Mu Alpha Theta () is the United States mathematics honor society for high school and two-year college students. In June 2015, it served over 108,000 student members in over 2,200 chapters in the United States and in 20 foreign countries. Its main goals are to inspire keen interest in mathematics, develop strong scholarship in the subject, and promote the enjoyment of mathematics in high school and two year college students. The name is a rough transliteration of math into Greek (Mu Alpha Theta). Buchholz High School won first place in 2023 for the 15th time in the annually held national convention.
History
The Mu Alpha Theta National High School and Three-Year College Mathematics Honor Society was founded in by Dr. Richard V. Andree and his wife, Josephine Andree, at the University of Oklahoma. In Andree's words, Mu Alpha Theta is "an organization dedicated to promoting scholarship in mathematics and establishing math as an integral part of high school and junior college education". The name Mu Alpha Theta was constructed from the Greek lettering for the phonemes "m", "a", and "th".
Pi Mu Epsilon, the National Collegiate Honor Society of Mathematics, contributed funds for the organization's initial expenses; the University of Oklahoma provided space, clerical help and technical assistance. The Mathematical Association of America, a primary sponsor of the organization since , and the National Council of Teachers of Mathematics nominated the first officers and Board of Gover
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https://en.wikipedia.org/wiki/Solarization%20%28physics%29
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Solarization refers to a phenomenon in physics where a material undergoes a temporary change in color after being subjected to high-energy electromagnetic radiation, such as ultraviolet light or X-rays. Clear glass and many plastics will turn amber, green or other colors when subjected to X-radiation, and glass may turn blue after long-term solar exposure in the desert. It is believed that solarization is caused by the formation of internal defects, called color centers, which selectively absorb portions of the visible light spectrum. In glass, color center absorption can often be reversed by heating the glass to high temperatures (a process called thermal bleaching) to restore the glass to its initial transparent state. Solarization may also permanently degrade a material's physical or mechanical properties, and is one of the mechanisms involved in the breakdown of plastics within the environment.
Examples
In the field of clinical imaging, with sufficient exposure, solarization of certain screen-film systems can occur which obscures details within the X-ray image and degrades the accuracy of the diagnosis. Even though degradation can occur this was found to be a rare phenomenon.
See also
Photodegradation
Solarized architectural glass
Atomic, molecular, and optical physics
Chromism
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https://en.wikipedia.org/wiki/PGL2
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PGL2 may refer to
SDHAF2, a gene on chromosome 11 in humans
for the group in mathematics, see projective linear group and modular group
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https://en.wikipedia.org/wiki/Discrete%20Laplace%20operator
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In mathematics, the discrete Laplace operator is an analog of the continuous Laplace operator, defined so that it has meaning on a graph or a discrete grid. For the case of a finite-dimensional graph (having a finite number of edges and vertices), the discrete Laplace operator is more commonly called the Laplacian matrix.
The discrete Laplace operator occurs in physics problems such as the Ising model and loop quantum gravity, as well as in the study of discrete dynamical systems. It is also used in numerical analysis as a stand-in for the continuous Laplace operator. Common applications include image processing, where it is known as the Laplace filter, and in machine learning for clustering and semi-supervised learning on neighborhood graphs.
Definitions
Graph Laplacians
There are various definitions of the discrete Laplacian for graphs, differing by sign and scale factor (sometimes one averages over the neighboring vertices, other times one just sums; this makes no difference for a regular graph). The traditional definition of the graph Laplacian, given below, corresponds to the negative continuous Laplacian on a domain with a free boundary.
Let be a graph with vertices and edges . Let be a function of the vertices taking values in a ring. Then, the discrete Laplacian acting on is defined by
where is the graph distance between vertices w and v. Thus, this sum is over the nearest neighbors of the vertex v. For a graph with a finite number of edges and vertices, th
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https://en.wikipedia.org/wiki/NLB
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NLB may refer to:
Nanotechnology Law & Business, a journal devoted to the legal, business, and policy aspects of nanotechnology
National Labor Board (1933–1934), a former agency of the US government
National League B, former name of the Swiss League, the second highest ice hockey league in Switzerland
National Library Board of Singapore
National Library for the Blind of the United Kingdom
Nationalliga B, former name of the Swiss Challenge League, the second highest football league in Switzerland
Negro league baseball (1885—1960), American baseball leagues with African-American players
Network Load Balancing, a technique for dividing computer network traffic among multiple network connections
New Lantao Bus, a bus service operator on Lantau Island, Hong Kong
New Left Books, former name of Verso Books, the book publishing arm of the New Left Review
NLB League, former name (2006—2011) of the ABA League (Adriatic League), a basketball league of teams from Bosnia and Herzegovina, Croatia, Montenegro, Serbia, and Slovenia
Norbert Leo Butz (born 1967), American musical theater actor
Northern Lighthouse Board, organisation responsible for marine navigation aids in Scotland and the Isle of Man
Nova Ljubljanska banka, the largest bank in Slovenia
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https://en.wikipedia.org/wiki/Bicubic%20interpolation
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In mathematics, bicubic interpolation is an extension of cubic spline interpolation (a method of applying cubic interpolation to a data set) for interpolating data points on a two-dimensional regular grid. The interpolated surface (meaning the kernel shape, not the image) is smoother than corresponding surfaces obtained by bilinear interpolation or nearest-neighbor interpolation. Bicubic interpolation can be accomplished using either Lagrange polynomials, cubic splines, or cubic convolution algorithm.
In image processing, bicubic interpolation is often chosen over bilinear or nearest-neighbor interpolation in image resampling, when speed is not an issue. In contrast to bilinear interpolation, which only takes 4 pixels (2×2) into account, bicubic interpolation considers 16 pixels (4×4). Images resampled with bicubic interpolation can have different interpolation artifacts, depending on the b and c values chosen.
Computation
Suppose the function values and the derivatives , and are known at the four corners , , , and of the unit square. The interpolated surface can then be written as
The interpolation problem consists of determining the 16 coefficients .
Matching with the function values yields four equations:
Likewise, eight equations for the derivatives in the and the directions:
And four equations for the mixed partial derivative:
The expressions above have used the following identities:
This procedure yields a surface on the
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https://en.wikipedia.org/wiki/Timelike%20Infinity
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Timelike Infinity is a 1992 science fiction book by British author Stephen Baxter. The second book in the Xeelee Sequence, Timelike Infinity introduces a universe of powerful alien species and technologies that manages to maintain a realistic edge because of Baxter's physics background. It largely sets the stage for the magnum opus of the Xeelee Sequence, Ring (as opposed to Vacuum Diagrams, Flux, or Raft, which concern themselves with side stories).
Plot summary
Set thousands of years in the future (AD 5407), the human race has been conquered by the Qax, a truly alien turbulent-liquid form of life, who now rule over the few star systems of human space – adopting processes from human history to effectively oppress the resentful race. Humans have encountered a few other races, including the astoundingly advanced Xeelee, and been conquered once before – by the Squeem – but successfully recovered.
A human-built device, the Interface project, returns to the Solar System after 1,500 years. The project, towed by the spaceship Cauchy, returns a wormhole gate, appearing to offer time travel due to the time 'difference' between the exits of the wormhole (relativistic time dilation), with one end having remained in the Solar System and the other travelling at near lightspeed for a century. The Qax had destroyed the Solar System gate, but a lashed-up human ship (a great chunk of soil including Stonehenge, crewed by a group called the Friends of Wigner) passes through the returning gat
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https://en.wikipedia.org/wiki/Michael%20H%C3%A4upl
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Michael Häupl (born 14 September 1949) is an Austrian politician. A member of the Social Democratic Party of Austria, he served as mayor and governor of Vienna from 7 November 1994 until 24 May 2018.
Early life and education
Häupl was born in Altlengbach, Lower Austria. He studied Biology and Zoology at the University of Vienna and was an academic assistant at the Vienna Natural History Museum from 1975 to 1983.
Political career
He was the State Chairman of the Socialist Students of Austria, the student organisation of the SPÖ from 1975 to 1978, a member of the Viennese Municipal Council from 1983 to 1988, and from 1988 until 1994, Executive City Councillor for Environment and Sport. Häupl followed Helmut Zilk in 1993 as a state party chairman of the SPÖ in Vienna and on 7 November 1994, he became the mayor of Vienna.
Häupl has won three elections since his appointment as mayor; each of them has led to increased majorities for the SPÖ. In the 1996 City Council election, the SPÖ lost its overall control of the 100-seat chamber with 43 seats on 39.15% of the vote. 1996 also saw a strong FPÖ, which won 29 seats (up from 21 in 1991), beating the ÖVP into third place for the second time running. For the period 1996-2001 the SPÖ governed Vienna in a coalition with the ÖVP.
In 2001 the SPÖ regained overall control with 52 seats on 46.91% of the vote; it improved on this in October 2005 with 55 seats on 49.09%. However, Häupl has also presided over a period of increased voter apa
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https://en.wikipedia.org/wiki/Levi%20graph
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In combinatorial mathematics, a Levi graph or incidence graph is a bipartite graph associated with an incidence structure. From a collection of points and lines in an incidence geometry or a projective configuration, we form a graph with one vertex per point, one vertex per line, and an edge for every incidence between a point and a line. They are named for Friedrich Wilhelm Levi, who wrote about them in 1942.
The Levi graph of a system of points and lines usually has girth at least six: Any 4-cycles would correspond to two lines through the same two points. Conversely any bipartite graph with girth at least six can be viewed as the Levi graph of an abstract incidence structure. Levi graphs of configurations are biregular, and every biregular graph with girth at least six can be viewed as the Levi graph of an abstract configuration.
Levi graphs may also be defined for other types of incidence structure, such as the incidences between points and planes in Euclidean space. For every Levi graph, there is an equivalent hypergraph, and vice versa.
Examples
The Desargues graph is the Levi graph of the Desargues configuration, composed of 10 points and 10 lines. There are 3 points on each line, and 3 lines passing through each point. The Desargues graph can also be viewed as the generalized Petersen graph G(10,3) or the bipartite Kneser graph with parameters 5,2. It is 3-regular with 20 vertices.
The Heawood graph is the Levi graph of the Fano plane. It is also known as the
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https://en.wikipedia.org/wiki/Closed%20monoidal%20category
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In mathematics, especially in category theory, a closed monoidal category (or a monoidal closed category) is a category that is both a monoidal category and a closed category in such a way that the structures are compatible.
A classic example is the category of sets, Set, where the monoidal product of sets and is the usual cartesian product , and the internal Hom is the set of functions from to . A non-cartesian example is the category of vector spaces, K-Vect, over a field . Here the monoidal product is the usual tensor product of vector spaces, and the internal Hom is the vector space of linear maps from one vector space to another.
The internal language of closed symmetric monoidal categories is linear logic and the type system is the linear type system. Many examples of closed monoidal categories are symmetric. However, this need not always be the case, as non-symmetric monoidal categories can be encountered in category-theoretic formulations of linguistics; roughly speaking, this is because word-order in natural language matters.
Definition
A closed monoidal category is a monoidal category such that for every object the functor given by right tensoring with
has a right adjoint, written
This means that there exists a bijection, called 'currying', between the Hom-sets
that is natural in both A and C. In a different, but common notation, one would say that the functor
has a right adjoint
Equivalently, a closed monoidal category is a category equippe
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https://en.wikipedia.org/wiki/Ian%20Foster%20%28computer%20scientist%29
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Ian Tremere Foster (born 1 January 1959) is a New Zealand-American computer scientist. He is a distinguished fellow, senior scientist, and director of the Data Science and Learning division at Argonne National Laboratory, and a professor in the department of computer science at the University of Chicago.
Education and career
Foster was born in Wellington, New Zealand, in 1959. He was educated at Wellington College and the University of Canterbury, followed by the Department of Computing, Imperial College London.
From 2006 to 2016, he was director of the Computation Institute (CI), a joint project between the University of Chicago, and Argonne National Laboratory.
CI brings together computational scientists and discipline leaders to work on projects with computation as a key component.
He is currently Director of the Data Science and Learning Division at Argonne National Laboratory, a unit established to tackle advanced scientific problems where data analysis and artificial intelligence can provide critical insights and accelerate discovery.
Honors
Foster's honors include the Gordon Bell Prize for high-performance computing (2001), the Lovelace Medal of the British Computer Society (2002), an honorary Doctor of Science from the University of Canterbury in 2005, the IEEE Tsutomu Kanai Award (2011), the IEEE Computer Society Charles Babbage Award, (with Carl Kesselman) the IEEE Computer Society Harry H Goode Memorial Award (2020), the IEEE Internet Award (2023), and the ACM
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https://en.wikipedia.org/wiki/Particle%20filter
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Particle filters, or sequential Monte Carlo methods, are a set of Monte Carlo algorithms used to find approximate solutions for filtering problems for nonlinear state-space systems, such as signal processing and Bayesian statistical inference. The filtering problem consists of estimating the internal states in dynamical systems when partial observations are made and random perturbations are present in the sensors as well as in the dynamical system. The objective is to compute the posterior distributions of the states of a Markov process, given the noisy and partial observations. The term "particle filters" was first coined in 1996 by Pierre Del Moral about mean-field interacting particle methods used in fluid mechanics since the beginning of the 1960s. The term "Sequential Monte Carlo" was coined by Jun S. Liu and Rong Chen in 1998.
Particle filtering uses a set of particles (also called samples) to represent the posterior distribution of a stochastic process given the noisy and/or partial observations. The state-space model can be nonlinear and the initial state and noise distributions can take any form required. Particle filter techniques provide a well-established methodology for generating samples from the required distribution without requiring assumptions about the state-space model or the state distributions. However, these methods do not perform well when applied to very high-dimensional systems.
Particle filters update their prediction in an approximate (statistica
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https://en.wikipedia.org/wiki/Closed%20category
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In category theory, a branch of mathematics, a closed category is a special kind of category.
In a locally small category, the external hom (x, y) maps a pair of objects to a set of morphisms. So in the category of sets, this is an object of the category itself. In the same vein, in a closed category, the (object of) morphisms from one object to another can be seen as lying inside the category. This is the internal hom [x, y].
Every closed category has a forgetful functor to the category of sets, which in particular takes the internal hom to the external hom.
Definition
A closed category can be defined as a category with a so-called internal Hom functor
with left Yoneda arrows
natural in and and dinatural in , and a fixed object of with a natural isomorphism
and a dinatural transformation
,
all satisfying certain coherence conditions.
Examples
Cartesian closed categories are closed categories. In particular, any topos is closed. The canonical example is the category of sets.
Compact closed categories are closed categories. The canonical example is the category FdVect with finite-dimensional vector spaces as objects and linear maps as morphisms.
More generally, any monoidal closed category is a closed category. In this case, the object is the monoidal unit.
References
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https://en.wikipedia.org/wiki/Homoplasmy
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Homoplasmy is a term used in genetics to describe a eukaryotic cell whose copies of mitochondrial DNA are all identical. In normal and healthy tissues, all cells are homoplasmic. Homoplasmic mitochondrial DNA copies may be normal or mutated; however, most mutations are heteroplasmic (only occurring in some copies of mitochondrial DNA). It has been discovered, though, that homoplasmic mitochondrial DNA mutations may be found in human tumors.
The term may also refer to uniformity of plant plastid DNA, whether occurring naturally or otherwise.
Inheritance
In almost every species, mitochondrial DNA is maternally inherited. This means that all of the offspring of a female will have identical and homoplasmic mitochondrial DNA. It is very rare for females to pass on heteroplasmic or homoplasmic mutations because of the genetic bottleneck, where only a few out of many mitochondria actually are passed on to offspring.
The mussel Mytilus edulis is an anomaly in terms of mitochondrial DNA inheritance. Unlike almost all animals, this species has biparental inheritance for mitochondrial DNA, meaning that both the male and the female contribute mitochondria to the offspring. This was discovered when researchers realized that most individuals of a Mytilus edulis population were heteroplasmic. Researchers also believe that this could be a by-product of species hybridization.
Mutations
There is evidence of both homoplasmic and heteroplasmic inherited mutations that lead to disease, thou
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https://en.wikipedia.org/wiki/Jean-Pierre%20Lebreton
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Jean-Pierre Lebreton (born 21 August 1949, in Thimert-Gâtelles, France) is a French planetary scientist at ESA, specialized in plasma physics. He was the mission manager of the Huygens probe that landed on Saturn's moon Titan in 2005. Besides the Huygens mission, Lebreton is also working with the Rosetta comet probe and its Plasma Consortium Experiment, and the Venus Express space probe.
References
External links
Interview with Lebreton
1949 births
Living people
European Space Agency personnel
Planetary scientists
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https://en.wikipedia.org/wiki/Walther%20Meissner
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Fritz Walther Meißner (anglicized: Meissner) (16 December 1882 – 16 November 1974) was a German technical physicist.
Meißner was born in Berlin to Waldemar Meißner and Johanna Greger. He studied mechanical engineering and physics at the Technical University of Berlin, his doctoral supervisor being Max Planck. He then entered the Physikalisch-Technische Bundesanstalt in Berlin. From 1922 to 1925, he established the world's third largest helium-liquifier, and discovered in 1933 the Meissner effect, damping of the magnetic field in superconductors. One year later, he was called as chair in technical physics at the Technical University of Munich.
After World War II, he became the president of the Bavarian Academy of Sciences and Humanities. In 1946, he was appointed director of the academy's first low temperature research commission. Laboratories were located in Herrsching am Ammersee until 1965, when they were moved to Garching. Meißner lived alone with his two dogs for the last several years of his life. Meißner died in Munich in 1974.
References
External links
Engineers from Berlin
Commanders Crosses of the Order of Merit of the Federal Republic of Germany
Academic staff of the Technical University of Munich
1882 births
1974 deaths
Members of the Bavarian Academy of Sciences
20th-century German physicists
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https://en.wikipedia.org/wiki/Willy%20Kyrklund
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Paul Wilhelm “Willy” Kyrklund (27 February 1921 in Helsinki, Finland – 27 June 2009 in Uppsala) was a Finnish Swedish-speaking author who lived in Uppsala, Sweden.
He was the son of an engineer. During World War II, he served on the front. In 1944, he moved from Finland to Sweden, where he studied Chinese, Russian, Persian and mathematics. He also worked as a programmer.
Kyrklund's works of fiction are influenced by modernism; his early short stories resemble surrealism, in which the storyline is concealed by symbolism that contributes to conveying a mix of bitter irony, reconciliation and alienation. These characteristics of his writings, together with Kyrklund's own absurdities, to some extent resemble the work of Torgny Lindgren. However, in contrast to surrealism, Kyrklund's works are highly aware and well thought out.
Recurring themes are pointlessness and powerlessness, where good and bad meet in an ungraspable and sometimes deliberately incomprehensible greyscale. Man is not born to sin; there is no choice, and sin becomes unavoidable. Often sinful deeds loom, while the future sinner observes in confusion, uncomprehending and unable to change the course of events. However, Kyrklund succeeded in portraying his failing characters with great empathy and indulgence, yet with the distance of an observer. In his stories, he often applied classical motives from the Bible and the antique era – motives that are structurally eternal, patterns that can not be broken.
Kyrklund
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https://en.wikipedia.org/wiki/Quintessence
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Quintessence, or fifth essence, may refer to:
Cosmology
Aether (classical element), in medieval cosmology and science, the fifth element that fills the universe beyond the terrestrial sphere
Quintessence (physics), a hypothetical form of dark energy, postulated to explain the accelerating expansion of the universe
Literature
Quintessence: Basic Readings from the Philosophy of W. V. Quine, essays by Willard Van Orman Quine
Quintessence: The Quality of Having It, a 1983 book by Betty Cornfeld and Owen Edwards
Works by Lawrence M. Krauss:
The Fifth Essence, a 1989 book
Quintessence: The Search for Missing Mass in the Universe, a 2000 book
Quintessence, a 2013 science fiction book by David Walton
Media companies
Quintessence Films, a film production company
Quintessence International Publishing Group, a publishing company founded in Berlin, Germany
Music
Quintessence Records, a budget label
Bands
Quintessence (English band), 1970s progressive rock band specializing in Indian themes and sounds
Quintessence (French band), black metal band, founded in 2005
Albums
The Quintessence, by Quincy Jones and his orchestra, 1962
Quintessence (Quintessence album), 1970
Quintessence (Bill Evans album), 1976
Quintessence (Borknagar album), 2000
Quintessential, by Steam Powered Giraffe, 2016
Quintessence (Spontaneous Music Ensemble album)
Songs
"Quintessence", by Darkthrone, from album Panzerfaust
"Quintessence", by Rotting Christ, from album Genesis
"Quintes
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