L-value (other)

	L-value (other) L-value, L value or lvalue may refer to: * In astronomy, a measure of brightness of a lunar eclipse on the Danjon scale * L-value (computer science), denoting an object to which values can be assigned * In number theory, the value of an L-function * In space physics, the value assigned to an L-shell The L-shell, L-value, or McIlwain L-parameter (after Carl E. McIlwain) is a parameter describing a particular set of planetary magnetic field lines. Colloquially, L-value often describes the set of magnetic field lines which cross the Eart ..., a particular set of planetary magnetic field lines See also * R-value (other) {{Disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Danjon Scale The Danjon scale is a five-point scale useful for measuring the appearance and luminosity of the Moon during a total lunar eclipse. It was proposed by André-Louis Danjon in 1921, when postulating that the brightness of a lunar eclipse was related to the solar cycle. An eclipse's rating on the scale is traditionally denoted by the letter ''L''. The scale The Danjon scale is described in the following table: Determining the value of L Determination of the value of L for an eclipse is best done near mid-totality with the naked eye. The scale is subjective, and different observers may determine different values. In addition, different parts of the Moon may have different L values, depending on their distance from the center of the Earth's umbra. Factors affecting the value of L Many factors can affect the appearance of the Moon during a lunar eclipse. The Moon's path through the Earth's umbra is important, but so too are the current conditions of the Earth's atmosphere. Wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	L-value (computer Science) In computer science and software programming, a value is the representation of some entity that can be manipulated by a program. The members of a type are the values of that type. The "value of a variable" is given by the corresponding mapping in the environment. In languages with assignable variables, it becomes necessary to distinguish between the ''r-value'' (or contents) and the ''l-value'' (or location) of a variable. In declarative (high-level) languages, values have to be referentially transparent. This means that the resulting value is independent of the location of the expression needed to compute the value. Only the contents of the location (the bits, whether they are 1 or 0) and their interpretation are significant. Value category Despite its name, in the C++ language standards this terminology is used to categorize expressions, not values. Assignment: l-values and r-values Some languages use the idea of l-values and r-values, deriving from the typical mode of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Special Values Of L-functions In mathematics, the study of special values of L-functions is a subfield of number theory devoted to generalising formulae such as the Leibniz formula for pi, namely :1 \,-\, \frac \,+\, \frac \,-\, \frac \,+\, \frac \,-\, \cdots \;=\; \frac,\! by the recognition that expression on the left-hand side is also ''L''(1) where ''L''(''s'') is the Dirichlet L-function for the Gaussian field. This formula is a special case of the analytic class number formula, and in those terms reads that the Gaussian field has class number 1, and also contains four roots of unity, so accounting for the factor ¼. Conjectures There are two families of conjectures, formulated for general classes of ''L''-functions (the very general setting being for ''L''-functions ''L''(''s'') associated to Chow motives over number fields), the division into two reflecting the questions of: how to replace π in the Leibniz formula by some other "transcendental" number (whether or not it is yet possible fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	L-shell The L-shell, L-value, or McIlwain L-parameter (after Carl E. McIlwain) is a parameter describing a particular set of planetary magnetic field lines. Colloquially, L-value often describes the set of magnetic field lines which cross the Earth's magnetic equator at a number of Earth-radii equal to the L-value. For example, "L=2" describes the set of the Earth's magnetic field lines which cross the Earth's magnetic equator two earth radii from the center of the Earth. L-shell parameters can also describe the magnetic fields of other planets. In such cases, the parameter is renormalized for that planet's radius and magnetic field model.Galileo - Glossary of Selected Terms'' NASA Jet Propulsion Laboratory, (2003). Although L-value is formally defined in terms of the Earth's true instantaneous magnetic field (or a high-order model like IGRF), it is often used to give a general picture of magnetic phenomena near the Earth, in which case it can be approximated using the dip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]