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R-value (plasticity) , a plasmid that cod ...
R-value or rvalue may refer to: * R-value (insulation) in building engineering, the efficiency of insulation of a house * R-value (soils) in geotechnical engineering, the stability of soils and aggregates for pavement construction * R-factor (crystallography), a measure of the agreement between the crystallographic model and the diffraction data * ''R''0 or ''R'' number, the basic reproduction number in epidemiology * In computer science, a pure value which cannot be assigned to * In statistics, the Pearson product-moment correlation coefficient, or simply ''correlation coefficient'' * In solid mechanics, the Lankford coefficient See also * L-value (other) * R rating (other) * R-factor Plasmid-mediated resistance is the transfer of antibiotic resistance genes which are carried on plasmids. Plasmids possess mechanisms that ensure their independent replication as well as those that regulate their replication number and guarantee st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R-value (insulation)
In the context of construction, the R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The ''R-value'' is the building industry term for thermal resistance "per unit area." It is sometimes denoted RSI-value if the SI units are used. An R-value can be given for a material (e.g. for polyethylene foam), or for an assembly of materials (e.g. a wall or a window). In the case of materials, it is often expressed in terms of R-value per metre. R-values are additive for layers of materials, and the higher the R-value the better the performance. The U-factor or U-value is the overall heat transfer coefficient and can be found by taking the inverse of the R-value. It is a property ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R-factor (crystallography)
In crystallography, the R-factor (sometimes called residual factor or reliability factor or the R-value or RWork) is a measure of the agreement between the crystallographic model and the experimental X-ray diffraction data. In other words, it is a measure of how well the refined structure predicts the observed data. The value is also sometimes called the discrepancy index, as it mathematically describes the difference between the experimental observations and the ideal calculated values. It is defined by the following equation: :R = \frac, where ''F'' is the so-called structure factor and the sum extends over all the reflections of X-rays measured and their calculated counterparts respectively. The structure factor is closely related to the intensity of the reflection it describes: :I_ \propto , F(hkl), ^2. The minimum possible value is zero, indicating perfect agreement between experimental observations and the structure factors predicted from the model. There is no theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Reproduction Number
In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted R_0 (pronounced ''R nought'' or ''R zero''), of an infection is the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection. The definition assumes that no other individuals are infected or immunized (naturally or through vaccination). Some definitions, such as that of the Australian Department of Health, add the absence of "any deliberate intervention in disease transmission". The basic reproduction number is not necessarily the same as the effective reproduction number R (usually written R_t 't'' for time sometimes R_e), which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. R_0 is a dimensionless number (persons infected per person infecting) and not a time rate, which would have units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Product-moment Correlation Coefficient
In statistics, the Pearson correlation coefficient (PCC, pronounced ) ― also known as Pearson's ''r'', the Pearson product-moment correlation coefficient (PPMCC), the bivariate correlation, or colloquially simply as the correlation coefficient ― is a measure of linear correlation between two sets of data. It is the ratio between the covariance of two variables and the product of their standard deviations; thus, it is essentially a normalized measurement of the covariance, such that the result always has a value between −1 and 1. As with covariance itself, the measure can only reflect a linear correlation of variables, and ignores many other types of relationships or correlations. As a simple example, one would expect the age and height of a sample of teenagers from a high school to have a Pearson correlation coefficient significantly greater than 0, but less than 1 (as 1 would represent an unrealistically perfect correlation). Naming and history It was developed by Karl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lankford Coefficient
The Lankford coefficient (also called Lankford value, R-value, or plastic strain ratio) is a measure of the plastic anisotropy of a rolled sheet metal. This scalar quantity is used extensively as an indicator of the formability of recrystallized low-carbon steel sheets.Ken-ichiro Mori, ''Simulation of Materials Processing: Theory, Methods and Applications'', (), p. 436 Definition If x and y are the coordinate directions in the plane of rolling and z is the thickness direction, then the R-value is given by : R = \cfrac where \epsilon^p_ is the in-plane plastic strain, transverse to the loading direction, and \epsilon^p_ is the plastic strain through-the-thickness. ISO 10113:202/ref> More recent studies have shown that the R-value of a material can depend strongly on the strain even at small strains . In practice, the R value is usually measured at 20% elongation in a tensile test. For sheet metals, the R values are usually determined for three different directions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
R Rating (other)
R rating may refer to: * R rating, a rating of the Canadian Home Video Rating System * R rating, a rating of the Korea Media Rating Board * R rating (Motion Picture Association), a rating of the Motion Picture Association film rating system * Restricted ratings of the Movie and Television Review and Classification Board in the Philippines * Restricted ratings of the Office of Film and Literature Classification in New Zealand * R18 (British Board of Film Classification), a rating by the British Board of Film Classification usually signifying hardcore pornography * R18+, a rating of the Australian Classification Board * R18 rating, a rating of Eirin in Japan See also *18 rating * M for Mature * Mature content *R. Rated * R-value (other) *R18 (other) R18, or R-18, may refer to: Media content ratings * R18 (British Board of Film Classification) * R18+ issued by the Australian Classification Board * R18 issued by the New Zealand Classification Office * R18+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
