Introduction. Beta-blockers, also known as beta-adrenoceptor blocking agents, are medications used to treat conditions such as angina, heart failure and high blood pressure. They decrease the activity of the heart by blocking the action of hormones like adrenaline.
1 The concept of âdemographic changeâ describes a populationâs age structure adjusting to. changes in living conditions. Consequently, changes in thcomposition of a societyâe s age. structure are the result of social shifts. (. 2  cf. . 3  theory of first and second demographic transition.
US Population to Hit 324 Million in 2016, 400 Million in 2050. The U.S. population is aging, and is moving away from one which is largely descended from people who came from Europe and more toward people from Central America, Mexico, and Asia. And, the rate at which the U.S population is growing has stagnated. There will be 323,996,000 Americans in 2016, barely up from 321,369,000 last year and slightly less than 326,626,000 in 2017. The U.S. population will not reach over 400,000,000 until 2051, when the Census forecasts it will reach 400,124,000.