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.
There are four factors that affect population change in a country: 1) Birth Rate-the number of live births per 1000 in a year. Birth rates are affected by such factors as nutrition, fertility, attitudes about abortion, labour value of children, government policies, social value, the availability of contraception and culture. 2) Death Rate-the number of deaths per 1000 in a year.