FeedbackFeedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to feed back into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems: Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument.
Action potentialAn action potential occurs when the membrane potential of a specific cell rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and in some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells.
European Economic AreaThe European Economic Area (EEA) was established via the Agreement on the European Economic Area, an international agreement which enables the extension of the European Union's single market to member states of the European Free Trade Association. The EEA links the EU member states and three EFTA states (Iceland, Liechtenstein, and Norway) into an internal market governed by the same basic rules. These rules aim to enable free movement of persons, goods, services, and capital within the European single market, including the freedom to choose residence in any country within this area.
European Economic CommunityThe European Economic Community (EEC) was a regional organisation created by the Treaty of Rome of 1957, aiming to foster economic integration among its member states. It was subsequently renamed the European Community (EC) upon becoming integrated into the first pillar of the newly formed European Union in 1993. In the popular language, however, the singular European Community was sometimes inaccurately used in the wider sense of the plural European Communities, in spite of the latter designation covering all the three constituent entities of the first pillar.
Greek War of IndependenceThe Greek War of Independence, also known as the Greek Revolution or the Greek Revolution of 1821, was a successful war of independence by Greek revolutionaries against the Ottoman Empire between 1821 and 1829. In 1826, the Greeks were assisted by the British Empire, Kingdom of France, and the Russian Empire, while the Ottomans were aided by their North African vassals, particularly the eyalet of Egypt. The war led to the formation of modern Greece, which would be expanded to its modern size in later years.
