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.
As the White House and Congress grapple over immigration legislation, the term chain migration has quickly become part of the D.C. lexicon. President Trump has blasted the practice as a massive immigration loophole that terrorists and truly evil people can exploit to infiltrate the U.S. Democrats have defended it as a cornerstone of America's immigration history.