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  2. R-factor (crystallography) - Wikipedia

    en.wikipedia.org/wiki/R-factor_(crystallography)

    Small molecules (up to ca. 1000 atoms) usually form better-ordered crystals than large molecules, and thus it is possible to attain lower R-factors. In the Cambridge Structural Database of small-molecule structures, more than 95% of the 500,000+ crystals have an R-factor lower than 0.15, and 9.5% have an R-factor lower than 0.03.

  3. Plasmid-mediated resistance - Wikipedia

    en.wikipedia.org/wiki/Plasmid-mediated_resistance

    R-factors are also called a resistance factors or resistance plasmid. They are tiny, circular DNA elements that are self-replicating, that contain antibiotic resistance genes. [ citation needed ] They were first found in Japan in 1959 when it was discovered that some Shigella strains had developed resistance to a number of antibiotics used to ...

  4. Coefficient of determination - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_determination

    Ordinary least squares regression of Okun's law.Since the regression line does not miss any of the points by very much, the R 2 of the regression is relatively high.. In statistics, the coefficient of determination, denoted R 2 or r 2 and pronounced "R squared", is the proportion of the variation in the dependent variable that is predictable from the independent variable(s).

  5. Unique factorization domain - Wikipedia

    en.wikipedia.org/wiki/Unique_factorization_domain

    For example, if R is the localization of k[x, y, z]/(x 2 + y 3 + z 7) at the prime ideal (x, y, z) then R is a local ring that is a UFD, but the formal power series ring R[[X]] over R is not a UFD. The Auslander–Buchsbaum theorem states that every regular local ring is a UFD.

  6. R-value (insulation) - Wikipedia

    en.wikipedia.org/wiki/R-value_(insulation)

    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 (in W/(m 2 ⋅K)) is the overall heat transfer coefficient and can be found by taking the inverse of the R-value. It is a property that ...

  7. Basic reproduction number - Wikipedia

    en.wikipedia.org/wiki/Basic_reproduction_number

    is the average number of people infected from one other person. For example, Ebola has an of two, so on average, a person who has Ebola will pass it on to two other people.. In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted (pronounced R nought or R zero), [1] of an infection is the ...

  8. Factor analysis - Wikipedia

    en.wikipedia.org/wiki/Factor_analysis

    For example, a sulfide mine is likely to be associated with high levels of acidity, dissolved sulfates and transition metals. These signatures can be identified as factors through R-mode factor analysis, and the location of possible sources can be suggested by contouring the factor scores. [54]

  9. r/K selection theory - Wikipedia

    en.wikipedia.org/wiki/R/K_selection_theory

    r-selected species are those that emphasize high growth rates, typically exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood (i.e., high r, low K). [10] A typical r species is the dandelion (genus Taraxacum).