Pulse wave velocity (PWV) is a measure of arterial stiffness.he study of the basic scientific principles of the velocity of the pulse wave through the arterial tree dates back to 1808 with the work of Thomas Young.
Put simply, chain migration is a derogatory term used to describe the ability of U.S. citizens and green card holders to bring their extended family into the country. A majority of the roughly one million foreigners who are allowed to enter the U.S. to become permanent residents each year are approved because they're related to Americans.
Gene flow is the movement of alleles between populations, which may make their gene pools more common. For example, if two areas trade birds by migration, gene flow is the switch of allele frequencies in each population, so each bird population loses a few alleles but gains a few alleles.enetic drift is the random change in the frequency of alleles within a population's gene pool. It can cause the genetic composition of a population to change in one direction â¦ or another.