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The scale factor is dimensionless, with counted from the birth of the universe and set to the present age of the universe: [4] giving the current value of as () or . The evolution of the scale factor is a dynamical question, determined by the equations of general relativity , which are presented in the case of a locally isotropic, locally ...
If a planet is detectable by both the radial-velocity and the transit methods, then both its true mass and its radius can be determined, as well as its density. Planets with low density are inferred to be composed mainly of hydrogen and helium, whereas planets of intermediate density are inferred to have water as a major constituent. A planet ...
In these equations, R(t) is the cosmological scale factor, is the Newtonian constant of gravitation, Λ is the cosmological constant with dimension length −2, ρ is the energy density and p is the isotropic pressure. k is constant throughout a particular solution, but may vary from one solution to another.
stands for muscle density; PCSA relates the force produced by the muscle to the summation of the forces produced along the force generating axis of each muscle fiber and is largely determined by the pennation angle. [3] [8] Fiber length is also a key variable in muscle anatomy.
The radial distribution function is an important measure because several key thermodynamic properties, such as potential energy and pressure can be calculated from it. For a 3-D system where particles interact via pairwise potentials, the potential energy of the system can be calculated as follows: [ 6 ]
Correlation functions are typically measured with scattering experiments. For example, x-ray scattering experiments directly measure electron-electron equal-time correlations. [7] From knowledge of elemental structure factors, one can also measure elemental pair correlation functions. See Radial distribution function for further
A wide variety of body composition measurement methods exist. The gold standard measurement technique for the 4-compartment model consists of a weight measurement, body density measurement using hydrostatic weighing or air displacement plethysmography, total body water calculation using isotope dilution analysis, and mineral content measurement by dual-energy X-ray absorptiometry (DEXA). [1]
In order to make the statistic a consistent estimator for the scale parameter, one must in general multiply the statistic by a constant scale factor. This scale factor is defined as the theoretical value of the value obtained by dividing the required scale parameter by the asymptotic value of the statistic. Note that the scale factor depends on ...