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 world population has grown tremendously over the past two thousand years. In 1999, the world population passed the six billion mark. The latest official current world population estimate, for mid-year 2013, is estimated at 7,095,217,980. The chart below shows past world population data back to the year one and future world population projections through the year 2083. World Population Growth