Wave amplitude formula_4 described by the equation: where The units of the amplitude depend on the type of wave. Transverse mechanical waves (e.g., a wave on a string) have an amplitude expressed as a distance (e.g., meters), longitudinal mechanical waves (e.g., sound waves) use units of pressure (e.g., pascals), and electromagnetic waves (a form of transverse vacuum wave) express the amplitude in terms of its electric field (e.g., volts/meter). The wavelength formula_30 is the distance between two sequential crests or troughs (or other equivalent points), generally is measured in meters. A wavenumber formula_17, the spatial frequency of the wave in radians
Genetic distance and Reynolds, Weir and Cockerham's genetic distance, listed below. In all the formulae in this section, formula_1 and formula_2 represent two different populations for which formula_3 loci have been studied. Let formula_4 represent the formula_5 allele at the formula_6 locus. In 1972, Masatoshi Nei published what came to be known as Nei's standard genetic distance. This distance has the nice property that if the rate of genetic change (amino acid substitution) is constant per year or generation then Nei's standard genetic distance ("D") increases in proportion to divergence time. This measure assumes that genetic differences are caused by mutation and