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.
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by availability of food.