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Eta
Eta (Η, η) is the seventh letter of the Greek alphabet Eta or ETA may also refer to: People * Eta (given name) * Eta, a derogatory term for the Burakumin in the Japanese feudal era * ETA, an Elvis Tribute Artist Aircraft * Eta (glider), a German glider * CNA Eta, an Italian aircraft Brands and enterprises * Eta, a snack food brand owned by Griffin's Foods * Empresa de Transporte Aéreo, a defunct Brazilian Airline * Environmental Transport Association, a British roadside assistance company * ETA SA, a Swiss watchmaking company * ETA Star Group, a Dubai-based investment company * ETA Systems, a defunct American computer manufacturer * ETA a.s., a Czech electrical appliances manufacturer Education * Engineering & Technologies Academy, in San Antonio, Texas, United States * Ethiopian Teachers' Association, a trade union * Evangelical Theological Academy, in Zwijndrecht, Netherlands * Evangelical Theological Association, a former teaching institute in Melbourne, Australia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
't Hooft Symbol
The t Hooft symbol is a collection of numbers which allows one to express the generators of the SU(2) Lie algebra in terms of the generators of Lorentz algebra. The symbol is a blend between the Kronecker delta and the Levi-Civita symbol. It was introduced by Gerard 't Hooft. It is used in the construction of the BPST instanton. η''a''μν is the 't Hooft symbol: :\eta^a_ = \begin \epsilon^ & \mu,\nu=1,2,3 \\ -\delta^ & \mu=4 \\ \delta^ & \nu=4 \\ 0 & \mu=\nu=4 \end . In other words, they are defined by ( a=1,2,3 ;~ \mu,\nu=1,2,3,4 ;~ \epsilon_=+1) : \eta_ = \epsilon_ + \delta_ \delta_ - \delta_ \delta_ : \bar \eta_ = \epsilon_ - \delta_ \delta_ + \delta_ \delta_ where the latter are the anti-self-dual 't Hooft symbols. More explicitly, these symbols are : \eta_ = \begin 0 & 0 & 0 & 1 \\ 0 & 0 & 1 & 0 \\ 0 & -1 & 0 & 0 \\ -1 & 0 & 0 & 0 \end, \quad \eta_ = \begin 0 & 0 & -1 & 0 \\ 0 & 0 & 0 & 1 \\ 1 & 0 & 0 & 0 \\ 0 & -1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta Meson
The eta () and eta prime meson () are isosinglet mesons made of a mixture of up, down and strange quarks and their antiquarks. The charmed eta meson () and bottom eta meson () are similar forms of quarkonium; they have the same spin and parity as the (light) defined, but are made of charm quarks and bottom quarks respectively. The top quark is too heavy to form a similar meson, due to its very fast decay. General The eta was discovered in pion–nucleon collisions at the Bevatron in 1961 by A. Pevsner ''et al''. at a time when the proposal of the Eightfold Way was leading to predictions and discoveries of new particles from symmetry considerations. The difference between the mass of the and that of the is larger than the quark model can naturally explain. This “ η–η′ puzzle ” can be resolved by the 't Hooft instanton mechanism, whose realization is also known as the Witten–Veneziano mechanism. Specifically, in QCD, the higher mass of the is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirichlet Eta Function
In mathematics, in the area of analytic number theory, the Dirichlet eta function is defined by the following Dirichlet series, which converges for any complex number having real part > 0: \eta(s) = \sum_^ = \frac - \frac + \frac - \frac + \cdots\approx \prod_^ \infty . This Dirichlet series is the alternating sum corresponding to the Dirichlet series expansion of the Riemann zeta function, ''ζ''(''s'') — and for this reason the Dirichlet eta function is also known as the alternating zeta function, also denoted ''ζ''*(''s''). The following relation holds: \eta(s) = \left(1-2^\right) \zeta(s) Both Dirichlet eta function and Riemann zeta function are special cases of Polylogarithm. While the Dirichlet series expansion for the eta function is convergent only for any complex number ''s'' with real part > 0, it is Abel summable for any complex number. This serves to define the eta function as an entire function. (The above relation and the facts that the eta function is ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ETA (separatist Group)
ETA, an acronym for Euskadi Ta Askatasuna ("Basque Homeland and Liberty"ETA BASQUE ORGANIZATION Encyclopaedia Britannica 20 October 2011 or "Basque Country and Freedom"), was an armed and far left separatist organization in the Basque Country (in northern Spain and southwestern France). The group was founded in 1959 and lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weierstrass Eta Function
In mathematics, the Weierstrass functions are special functions of a complex variable that are auxiliary to the Weierstrass elliptic function. They are named for Karl Weierstrass. The relation between the sigma, zeta, and \wp functions is analogous to that between the sine, cotangent, and squared cosecant functions: the logarithmic derivative of the sine is the cotangent, whose derivative is negative the squared cosecant. Weierstrass sigma function The Weierstrass sigma function associated to a two-dimensional lattice (group), lattice \Lambda\subset\Complex is defined to be the product : \begin \operatorname&=z\prod_ \left(1-\frac\right) e^ \\ &=z\prod_^\infty \left(1-\frac\right) e^ \end where \Lambda^ denotes \Lambda-\ or \ are a ''fundamental pair of periods''. Through careful manipulation of the Weierstrass factorization theorem as it relates also to the sine function, another potentially more manageable infinite product definition is : \operatorname=\frace^\sin\prod_^\infty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Travel Authorization
An electronic visa, electronic entry visa or electronic travel authorisation/electronic travel authority (ETA) is a travel permit in an electronic form. It is often required in addition to a valid passport for access into a particular jurisdiction. Background Beginning in the 2000s many countries introduced e-visas and electronic travel authorisations (ETAs) as an alternative to traditional visas. An ETA is a kind of pre-arrival registration, which may or may not be officially classified as a visa depending on the issuing jurisdiction, required for foreign travellers who are exempted from obtaining a full visa. In contrast to the procedures that typically apply in regard to proper visas, per which the traveller normally has no recourse if rejected, if an ETA is rejected the traveller can choose to apply for a visa instead. In contrast, an e-visa is simply a visa that travellers can apply for and receive online without visiting the issuing state's consular mission or visa agency. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exfoliatin
Exfoliatin is a '' Staphylococcus aureus'' exotoxin that causes a blistering of the skin known as staphylococcal scalded skin syndrome, usually in infants. Exfoliatins are glutamate-specific serine proteases highly specific to desmoglein I, a cadherin (adhesion protein) in the desmosomes of the stratum granulosum that facilitates intercellular adhesion between keratinocytes. The resulting vesicle is an intraepidermal cleft located above the basal cells (suprabasal), between the stratum corneum and stratum spinosum. A very similar non-infectious condition is seen in the autoimmune skin disorder pemphigus vulgaris in which there is an IgG antibody against the cadherin desmoglein 3 Desmoglein-3 is a protein that in humans is encoded by the ''DSG3'' gene. In the skin epidermis Desmoglein-3 is expressed in the basal lower layers of the epidermis, and dominates in terms of expression on mucosal surfaces compared to Desmoglein-1. .... See also * Exfoliation (other) * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Tree Analysis
Event tree analysis (ETA) is a forward, top-down, logical modeling technique for both success and failure that explores responses through a single initiating event and lays a path for assessing probabilities of the outcomes and overall system analysis. This analysis technique is used to analyze the effects of functioning or failed systems given that an event has occurred.Wang, John '' et al.'' (2000). ETA is a powerful tool that will identify all consequences of a system that have a probability of occurring after an initiating event that can be applied to a wide range of systems including: nuclear power plants, spacecraft, and chemical plants. This technique may be applied to a system early in the design process to identify potential issues that may arise, rather than correcting the issues after they occur. With this forward logic process, use of ETA as a tool in risk assessment can help to prevent negative outcomes from occurring, by providing a risk assessor with the probabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanolamine
Ethanolamine (2-aminoethanol, monoethanolamine, ETA, or MEA) is an organic chemical compound with the formula or . The molecule is bifunctional, containing both a primary amine and a primary alcohol. Ethanolamine is a colorless, viscous liquid with an odor reminiscent of ammonia.. ETA molecules are a component in the formation of cellular membranes and are thus a molecular building block for life. It was thought to exist only on Earth and on certain asteroids, but in 2021 evidence was found that ETA molecules exist in interstellar space. Derivatives of ethanolamine are widespread in nature; e.g., lipids, as precursor of a variety of ''N''-acylethanolamines (NAEs), that modulate several animal and plant physiological processes such as seed germination, plant–pathogen interactions, chloroplast development and flowering, as well as precursor, combined with arachidonic acid 20: 4, ω-6), to form the endocannabinoid anandamide (AEA: ; 20:4, ω-6). The ethanolamines comprise a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eicosatetraenoic Acid
Eicosatetraenoic acid (ETA) designates any straight chain 20:4 fatty acid. Eicosatetraenoic acid belongs to the family of eicosanoids, molecules synthesized from oxidized polyunsaturated fatty acids (PUFAs) to mediate cell-cell communication. The eicosanoids, working in tandem, contribute to a lipid signaling complex widely responsible for inducing an inflammatory immune response. Common signs of inflammation are both internal and external, with effects like visible redness, pain in the surrounding area, swelling, and the sensation of heat—many of these an effect of varying eicosanoid species. These effects are associated with and have been observed in patients with cancers and various neurological/metabolic disorders. :''See Essential Fatty Acid for nomenclature.'' Two isomers, both of them essential fatty acids, are of particular interest: * ''all-cis''-5,8,11,14-eicosatetraenoic acid is an ω-6 fatty acid with the trivial name arachidonic acid. It is formed by a desaturation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta Invariant
In mathematics, the eta invariant of a self-adjoint elliptic differential operator on a compact manifold is formally the number of positive eigenvalues minus the number of negative eigenvalues. In practice both numbers are often infinite so are defined using zeta function regularization. It was introduced by who used it to extend the Hirzebruch signature theorem to manifolds with boundary. The name comes from the fact that it is a generalization of the Dirichlet eta function. They also later used the eta invariant of a self-adjoint operator to define the eta invariant of a compact odd-dimensional smooth manifold. defined the signature defect of the boundary of a manifold as the eta invariant, and used this to show that Hirzebruch's signature defect of a cusp of a Hilbert modular surface can be expressed in terms of the value at ''s''=0 or 1 of a Shimizu L-function. Definition The eta invariant of self-adjoint operator ''A'' is given by ''η''''A''(0), where ''η'' is the an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta Conversion
Lambda calculus (also written as ''λ''-calculus) is a formal system in mathematical logic for expressing computability, computation based on function Abstraction (computer science), abstraction and function application, application using variable Name binding, binding and Substitution (algebra), substitution. It is a universal model of computation that can be used to simulate any Turing machine. It was introduced by the mathematician Alonzo Church in the 1930s as part of his research into the foundations of mathematics. Lambda calculus consists of constructing #Lambda terms, § lambda terms and performing #Reduction, § reduction operations on them. In the simplest form of lambda calculus, terms are built using only the following rules: * x – variable, a character or string representing a parameter or mathematical/logical value. * (\lambda x.M) – abstraction, function definition (M is a lambda term). The variable x becomes Free variables and bound variables, bound in the expre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
