|
Ar Es Salaam
AR, Ar, or A&R may refer to: Arts, entertainment, and media Music * Artists and repertoire Periodicals * ''Absolute Return + Alpha'', a hedge fund publication *''The Adelaide Review'', an Australian arts magazine * ''American Renaissance'' (magazine), a white nationalist magazine and website * ''Architectural Review'', a British architectural journal * '' Armeerundschau'', a magazine of the East German army Other media * Ar, city on the fictional planet Gor * ''a.r.'' group of Polish artists and poets, including Katarzyna Kobro * Alternate reality (other), various fictional concepts Business * Accounts receivable, abbreviated as AR or A/R * Acoustic Research, an American audio electronics manufacturer * Aerojet Rocketdyne, an American aerospace and defense manufacturer * Aerolíneas Argentinas (IATA airline code AR) * Some Alfa Romeo car models, e.g. AR51 * Toyota AR engine Language * ''Ar'', the Latin letter R when spelled out * Ar (cuneiform), a cuneiform combin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artists And Repertoire
Artists and repertoire (colloquially abbreviated to A&R) is the division of a record label or music publishing company that is responsible for talent scouting and overseeing the artistic development of recording artists (singers, instrumentalists, bands, and so on) and songwriters. It also acts as a liaison between artists and the record label or publishing company; every activity involving artists to the point of album release is generally considered under the purview, and responsibility, of A&R. Responsibilities Finding talent The A&R division of a record label is responsible for finding new recording artists and bringing those artists to the record company. A&R staff may go to hear emerging bands play at nightclubs and festivals to scout for talent. Personnel in the A&R division are expected to understand the current tastes of the market and to be able to find artists that will be commercially successful. For this reason, A&R people are often young and many are musicians, mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerated Reader
Accelerated Reader (AR) is a website used to assist students with reading skills. Components ATOS ATOS is a readability formula designed by Renaissance Learning. Books with quizzes in Accelerated Reader are assigned an ATOS readability level. Quiz Accelerated (going up to 7th grade) Reader (AR) quizzes are available on fiction and non-fiction books, textbooks, supplemental materials, and magazines. Most are in the form of reading practice quizzes, although some are curriculum-based with multiple subjects. Many of the company's quizzes are available in an optional recorded voice format for primary-level books, in which the quiz questions and answers are read to the student taking the quiz. These quizzes are designed to help emerging English and some Spanish readers take the quizzes without additional assistance. The Renaissance Place version of Accelerated Reader also includes quizzes designed to practice vocabulary. The quizzes use words from books, and are taken after the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspect Ratio (aeronautics)
In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.Kermode, A.C. (1972), ''Mechanics of Flight'', Chapter 3, (p.103, eighth edition), Pitman Publishing Limited, London Aspect ratio and other features of the planform are often used to predict the aerodynamic efficiency of a wing because the lift-to-drag ratio increases with aspect ratio, improving the fuel economy in powered airplanes and the gliding angle of sailplanes. Definition The aspect ratio \text is the ratio of the square of the wingspan b to the projected wing area S, which is equal to the ratio of the wingspan b to the standard mean chord \text: \text \equiv \frac = \frac Mechanism As a useful simplification, an airplane in flight can be imagined to affect a circular cylinder of air with a diameter equal to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-reflective
An antireflective, antiglare or anti-reflection (AR) coating is a type of optical coating applied to the surface of lenses, other optical elements, and photovoltaic cells to reduce reflection. In typical imaging systems, this improves the efficiency since less light is lost due to reflection. In complex systems such as cameras, binoculars, telescopes, and microscopes the reduction in reflections also improves the contrast of the image by elimination of stray light. This is especially important in planetary astronomy. In other applications, the primary benefit is the elimination of the reflection itself, such as a coating on eyeglass lenses that makes the eyes of the wearer more visible to others, or a coating to reduce the glint from a covert viewer's binoculars or telescopic sight. Many coatings consist of transparent thin film structures with alternating layers of contrasting refractive index. Layer thicknesses are chosen to produce destructive interference in the beams ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Atomic Mass
Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a given sample to the atomic mass constant. The atomic mass constant (symbol: ''m'') is defined as being of the mass of a carbon-12 atom. Since both quantities in the ratio are masses, the resulting value is dimensionless; hence the value is said to be ''relative''. For a single given sample, the relative atomic mass of a given element is the weighted arithmetic mean of the masses of the individual atoms (including their isotopes) that are present in the sample. This quantity can vary substantially between samples because the sample's origin (and therefore its radioactive history or diffusion history) may have produced unique combinations of isotopic abundances. For example, due to a different mixture of stable carbon-12 and carbon-13 isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aryl
In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the aryl group in chemical structure diagrams, analogous to “R” used for any organic substituent. “Ar” is not to be confused with the elemental symbol for argon. A simple aryl group is phenyl (), a group derived from benzene. Examples of other aryl groups consist of: * The tolyl group () which is derived from toluene (methylbenzene) * The xylyl group (), which is derived from xylene (dimethylbenzene) * The naphthyl group (), which is derived from naphthalene Arylation is the process in which an aryl group is attached to a substituent. It is typically achieved by cross-coupling reactions. Nomenclature The most basic aryl group is phenyl, which is made up of a benzene ring with one hydrogen atom substituted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon
Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust. Nearly all of the argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas. The name "argon" is derived from the Greek word , neuter singular form of meaning 'lazy' or 'inactive', as a reference to the fact that the element undergoes almost no chemical reactions. The complete octe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archimedes Number
In viscous fluid dynamics, the Archimedes number (Ar), is a dimensionless number used to determine the motion of fluids due to density differences, named after the ancient Greek scientist and mathematician Archimedes. It is the ratio of gravitational forces to viscous forces and has the form: :\begin\mathrm & = \frac \\ & = \frac \\ \end where: * g is the local external field (for example gravitational acceleration), , * L is the characteristic length of body, . * \frac is the submerged specific gravity, * \rho_\ell is the density of the fluid, , * \rho is the density of the body, , * \nu = \frac is the kinematic viscosity, , * \mu is the dynamic viscosity, , Uses The Archimedes number is generally used in design of tubular chemical process reactors. The following are non-exhaustive examples of using the Archimedes number in reactor design. Packed-bed fluidization design The Archimedes number is applied often in the engineering of packed beds, which are very common in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoregressive Model
In statistics, econometrics and signal processing, an autoregressive (AR) model is a representation of a type of random process; as such, it is used to describe certain time-varying processes in nature, economics, etc. The autoregressive model specifies that the output variable depends linearly on its own previous values and on a stochastic term (an imperfectly predictable term); thus the model is in the form of a stochastic difference equation (or recurrence relation which should not be confused with differential equation). Together with the moving-average (MA) model, it is a special case and key component of the more general autoregressive–moving-average (ARMA) and autoregressive integrated moving average (ARIMA) models of time series, which have a more complicated stochastic structure; it is also a special case of the vector autoregressive model (VAR), which consists of a system of more than one interlocking stochastic difference equation in more than one evolving random vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverse Hyperbolic Functions
In mathematics, the inverse hyperbolic functions are the inverse functions of the hyperbolic functions. For a given value of a hyperbolic function, the corresponding inverse hyperbolic function provides the corresponding hyperbolic angle. The size of the hyperbolic angle is equal to the area of the corresponding hyperbolic sector of the hyperbola , or twice the area of the corresponding sector of the unit hyperbola , just as a circular angle is twice the area of the circular sector of the unit circle. Some authors have called inverse hyperbolic functions "area functions" to realize the hyperbolic angles. Hyperbolic functions occur in the calculations of angles and distances in hyperbolic geometry. It also occurs in the solutions of many linear differential equations (such as the equation defining a catenary), cubic equations, and Laplace's equation in Cartesian coordinates. Laplace's equations are important in many areas of physics, including electromagnetic theory, heat tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive Inheritance
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomplete d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
