In biology, homeostasis (British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium, and calcium ions, as well as the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in optimal conditions, and equilibrium is maintained by many regulatory mechanisms: it is thought to be the central motivation for all organic action. All homeostatic control...

An ostracon (Greek: ὄστρακον ostrakon, plural ὄστρακα ostraka) is a piece of pottery, usually broken off from a vase or other earthenware vessel. In an archaeological or epigraphical context, ostraca refer to sherds or even small pieces of stone that have writing scratched into them. Usually these are considered to have been broken off before the writing was added; ancient people used the cheap, plentiful and durable broken pieces of pottery around them as a convenient medium to write on for a wide variety of purposes, mostly very short inscriptions, but in some cases very long. Ostracism In Classical Athens, when the decision at hand was to banish or exile a certain member of society, citizen peers would cast their vote by writing the name of the person on the shard of pottery; the vote was counted and, if unfavorable, the person was exiled for a period of ten years from the city, thus giving rise to the term ostracism. Broken pottery...

Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are used to maintain quality standards, improve performance, and provide credibility. In academia, scholarly peer review is often used to determine an academic paper's suitability for publication. Peer review can be categorized by the type of activity and by the field or profession in which the activity occurs, e.g., medical peer review. It can also be used as a teaching tool to help students improve writing assignments. Henry Oldenburg (1619–1677) was a German-born British philosopher who is seen as the 'father' of modern scientific peer review. Professional Professional peer review focuses on the performance of professionals, with a view to improving quality, upholding standards, or providing certification. In academia, peer review is used to inform decisions...

John Gerard (also John Gerarde, c. 1545–1612) was an English herbalist with a large garden in Holborn, now part of London. His 1,484-page illustrated Herball, or Generall Historie of Plantes, first published in 1597, became a popular gardening and herbal book in English in the 17th century. Except for some added plants from his own garden and from North America, Gerard's Herbal is largely a plagiarized English translation of Rembert Dodoens's 1554 herbal, itself highly popular in Dutch, Latin, French and other English translations. Gerard's Herball drawings of plants and the printer's woodcuts are mainly derived from Continental European sources, but there is an original title page with a copperplate engraving by William Rogers. Two decades after Gerard's death, the book was corrected and expanded to about 1,700 pages. Life Early life and education Gerard was born at Nantwich, Cheshire, towards the end of 1545, receiving his only schooling at nearby Willaston, about two miles away. Nothing is known of his parentage, but the...

The Burgtheater (literally:"Castle Theater" but alternatively translated as "(Imperial) Court Theater"), originally known as K.K. Theater an der Burg, then until 1918 as the K.K. Hofburgtheater, is the national theater of Austria in Vienna. It is the most important German-language theater and one of the most important theatres in the world. The Burgtheater was opened in 1741 and has become known as "die Burg" by the Viennese population; its theater company has created a traditional style and speech typical of Burgtheater performances. History The original Burgtheater was set up in a tennis court (called a 'ball house' at the time) that the Roman-German king and later emperor Ferdinand I had built in 1540 in the lower pleasure garden of the Hofburg after the old ball house fell victim to a fire in 1525.The theater opened on 14 March 1741, the creation of the Habsburg Empress Maria Theresa of Austria, who wanted a theater next to her palace. Her son, Emperor Joseph II, called it the "German National Theater" in 1776. Three Mozart operas premiered there: Die Entführung...

The environmental movement (sometimes referred to as the ecology movement), also including conservation and green politics, is a diverse philosophical, social, and political movement for addressing environmental issues. Environmentalists advocate the just and sustainable management of resources and stewardship of the environment through changes in public policy and individual behaviour. In its recognition of humanity as a participant in (not enemy of) ecosystems, the movement is centered on ecology, health, and human rights. The environmental movement is an international movement, represented by a range of organizations, from enterprises to grassroots and varies from country to country. Due to its large membership, varying and strong beliefs, and occasionally speculative nature, the environmental movement is not always united in its goals. The movement also encompasses some other movements with a more specific focus, such as the climate movement. At its broadest, the movement includes private citizens, professionals, religious devotees, politicians, scientists, nonprofit organizations, and individual advocates. ...

The North Atlantic Treaty Organization (NATO, ; French: Organisation du traité de l'Atlantique nord, OTAN), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two North American. Established in the aftermath of World War II, the organization implemented the North Atlantic Treaty, signed in Washington, D.C., on 4 April 1949. NATO is a collective security system: its independent member states agree to defend each other against attacks by third parties. During the Cold War, NATO operated as a check on the perceived threat posed by the Soviet Union. The alliance remained in place after the dissolution of the Soviet Union and has been involved in military operations in the Balkans, the Middle East, South Asia, and Africa. The organization's motto is animus in consulendo liber (Latin for "a mind unfettered in deliberation"). NATO's main headquarters are located in Brussels, Belgium, while NATO's military headquarters are near Mons, Belgium. The alliance...

The pardessus de viole is the highest-pitched member of the viol family of instruments. It is a bowed string instrument with either five or six strings and a fretted neck. The pardessus first appeared in the early 18th century, and was commonly played by women, particularly in French-speaking countries. Description The pardessus de viole is the smallest of the viol family. Its size is similar to the violin's, and its range is correspondingly similar. The strings are made of gut (like on any bowed string instrument until the 1970s) and the top string was tuned to g'', a fourth higher than the top string of the treble viol. Like the treble viol, the pardessus de viole was almost never used to play accompaniment chords, but was always a melody instrument. When played, it is played upright on the lap with a bow.Unlike the treble viol and other viol instruments, the pardessus usually has only five strings. The five string pardessus is tuned in fifths and fourths (g, d', a', d'', g''), while six stringed pardessus are tuned like other viols in fourths with a third (g, c', e', a', d'', g'' or g, c', f', a', d'', g''). ...

In a religious context, sin is a transgression against divine law or a law of God. Each culture has its own interpretation of what it means to commit a sin. While sins are generally considered actions, any thought, word, or act considered immoral, selfish, shameful, harmful, or alienating might be termed "sinful". Etymology From Middle English sinne, synne, sunne, zen, from Old English synn (“sin”), from Proto-West Germanic *sunnju, from Proto-Germanic *sunjō (“truth, excuse”) and *sundī, *sundijō (“sin”), from Proto-Indo-European *h₁s-ónt-ih₂, from *h₁sónts ("being, true", implying a verdict of "truly guilty" against an accusation or charge), from *h₁es- (“to be”); compare Old English sōþ ("true"; see sooth). Doublet of suttee. Bahá'í Baháʼís consider humans to be naturally good, fundamentally spiritual beings. Human...

In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformation of at least one nuclide to another. If a nucleus interacts with another nucleus or particle and they then separate without changing the nature of any nuclide, the process is simply referred to as a type of nuclear scattering, rather than a nuclear reaction. In principle, a reaction can involve more than two particles colliding, but because the probability of three or more nuclei to meet at the same time at the same place is much less than for two nuclei, such an event is exceptionally rare (see triple alpha process for an example very close to a three-body nuclear reaction). The term "nuclear reaction" may refer either to a change in a nuclide induced by collision with another particle or to a spontaneous change of a nuclide without collision. Natural nuclear reactions occur in the interaction between cosmic rays and matter, and nuclear reactions can be employed artificially to obtain nuclear energy, at an adjustable...