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.
The Changing Demographic Profile of the United States Congressional Research Service 1 he United States, the third-largest population globally, accounts for about 4.5% of the worldâs population. The U.S. populationâestimated in the 2010 Census at 308.7 million