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.
Demographic transition model. a model of population change from equilibrium with high birth/death states through a high growth transition period in which death rates decline sooner than birth rates to a new equilibrium w/low birth and death rates.emographic transition model. a model of population change from equilibrium with high birth/death states through a high growth transition period in which death rates decline sooner than birth rates to a new equilibrium w/low birth and death rates.