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🔗 Chess

Kriegspiel is a chess variant invented by Henry Michael Temple in 1899 and based upon the original Kriegsspiel (German for war game) developed by Georg von Reiswitz in 1812. In this game each player can see their own pieces, but not those of their opponent. For this reason, it is necessary to have a third person (or computer) act as an umpire, with full information about the progress of the game. When it is a player's turn he or she will attempt a move, which the umpire will declare to be 'legal' or 'illegal'. If the move is illegal, the player tries again; if it is legal, that move stands. Each player is given information about checks and captures. They may also ask the umpire if there are any legal captures with a pawn. Since the position of the opponent's pieces is unknown, Kriegspiel is a game of imperfect information. The game is sometimes referred to as blind chess.

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/World War II 🔗 Austria 🔗 Military history/German military history 🔗 Military history/French military history 🔗 Military history/European military history

The Battle for Castle Itter was fought in the Austrian North Tyrol village of Itter on 5 May 1945, in the last days of the European Theater of World War II.

Troops of the 23rd Tank Battalion of the 12th Armored Division of the US XXI Corps led by Captain John C. "Jack" Lee, Jr., a number of Wehrmacht soldiers led by Major Josef "Sepp" Gangl, SS-Hauptsturmführer Kurt-Siegfried Schrader, and recently freed French prisoners of war defended Castle Itter against an attacking force from the 17th SS Panzergrenadier Division until relief from the American 142nd Infantry Regiment of the 36th Division of XXI Corps arrived.

The French prisoners included former prime ministers, generals and a tennis star. It is the only known time during the war in which Americans and Germans fought side-by-side. Popular accounts of the battle have called it the strangest battle of World War II.

🔗 Computing 🔗 Classical Greece and Rome 🔗 Greece 🔗 Astronomy 🔗 History of Science 🔗 Alternative Views 🔗 Time

The Antikythera mechanism (, ) is an ancient hand powered Greek analogue computer which has also been described as the first example of such device used to predict astronomical positions and eclipses for calendar and astrological purposes decades in advance. It could also be used to track the four-year cycle of athletic games which was similar to an Olympiad, the cycle of the ancient Olympic Games.

This artefact was retrieved from the sea in 1901, and identified on 17 May 1902 as containing a gear by archaeologist Valerios Stais, among wreckage retrieved from a shipwreck off the coast of the Greek island Antikythera. The instrument is believed to have been designed and constructed by Greek scientists and has been variously dated to about 87 BC, or between 150 and 100 BC, or to 205 BC, or to within a generation before the shipwreck, which has been dated to approximately 70–60 BC.

The device, housed in the remains of a 34 cm × 18 cm × 9 cm (13.4 in × 7.1 in × 3.5 in) wooden box, was found as one lump, later separated into three main fragments which are now divided into 82 separate fragments after conservation efforts. Four of these fragments contain gears, while inscriptions are found on many others. The largest gear is approximately 14 centimetres (5.5 in) in diameter and originally had 223 teeth.

It is a complex clockwork mechanism composed of at least 30 meshing bronze gears. A team led by Mike Edmunds and Tony Freeth at Cardiff University used modern computer x-ray tomography and high resolution surface scanning to image inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine.

Detailed imaging of the mechanism suggests that it had 37 gear wheels enabling it to follow the movements of the Moon and the Sun through the zodiac, to predict eclipses and even to model the irregular orbit of the Moon, where the Moon's velocity is higher in its perigee than in its apogee. This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine's construction.

The knowledge of this technology was lost at some point in antiquity. Similar technological works later appeared in the medieval Byzantine and Islamic worlds, but works with similar complexity did not appear again until the development of mechanical astronomical clocks in Europe in the fourteenth century. All known fragments of the Antikythera mechanism are now kept at the National Archaeological Museum in Athens, along with a number of artistic reconstructions and replicas of the mechanism to demonstrate how it may have looked and worked.

🔗 Spaceflight 🔗 Physics

A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetic field. Earth has two such belts and sometimes others may be temporarily created. The discovery of the belts is credited to James Van Allen, and as a result, Earth's belts are known as the Van Allen belts. Earth's two main belts extend from an altitude of about 640 to 58,000 km (400 to 36,040 mi) above the surface in which region radiation levels vary. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays. By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction.

The belts are located in the inner region of Earth's magnetosphere. The belts trap energetic electrons and protons. Other nuclei, such as alpha particles, are less prevalent. The belts endanger satellites, which must have their sensitive components protected with adequate shielding if they spend significant time near that zone. In 2013, NASA reported that the Van Allen Probes had discovered a transient, third radiation belt, which was observed for four weeks until it was destroyed by a powerful, interplanetary shock wave from the Sun.

🔗 Medicine 🔗 Psychology 🔗 Linguistics 🔗 Linguistics/Applied Linguistics 🔗 Education

Spaced repetition is an evidence-based learning technique that is usually performed with flashcards. Newly introduced and more difficult flashcards are shown more frequently while older and less difficult flashcards are shown less frequently in order to exploit the psychological spacing effect. The use of spaced repetition has been shown to increase rate of learning.

Although the principle is useful in many contexts, spaced repetition is commonly applied in contexts in which a learner must acquire many items and retain them indefinitely in memory. It is, therefore, well suited for the problem of vocabulary acquisition in the course of second-language learning. A number of spaced repetition software programs have been developed to aid the learning process. Alternative names for spaced repetition include spaced rehearsal, expanding rehearsal, graduated intervals, repetition spacing, repetition scheduling, spaced retrieval and expanded retrieval.

Vital articles are lists of subjects for which the English Wikipedia should have corresponding featured-class articles. They serve as centralized watchlists to track the status of Wikipedia's most important articles. The very most important articles are in Level 1.

This page constitutes Level 3 of the vital articles list and includes approximately 1,000 articles. All articles from higher levels are also included in lower levels. For example, all 100 subjects on the Level 2 list (shown on this page in bold font) are included here in Level 3. And the Level 2 list also includes the 10 subjects on Level 1 (shown on this page in bold italics). A larger Level 4 list of 10,000 articles also exists, and a Level 5 list of 50,000 articles is in the process of being created.

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This list is tailored to the English-language Wikipedia. There is also a list of one thousand articles considered vital to Wikipedias of all languages, as well as Vital Article lists tailored to different Wikipedia languages accessible via the languages sidebar.

Articles should not be added or removed from this list without a consensus on the talk page. For more information on this list and the process for adding or removing articles, please see the Frequently Asked Questions (FAQ) page.

🔗 Insects 🔗 Diptera

Toxorhynchites, also called elephant mosquito or mosquito eater, is a genus of diurnal and often relatively colorful mosquitoes, found worldwide between about 35° north and 35° south. It includes the largest known species of mosquito, at up to 18 mm (0.71 in) in length and 24 mm (0.94 in) in wingspan. It is among the many kinds of mosquito that do not consume blood. The adults subsist on carbohydrate-rich materials, such as honeydew, or saps and juices from damaged plants, refuse, fruit, and nectar.

Their larvae prey on the larvae of other mosquitoes and similar nektonic prey, making Toxorhynchites beneficial to humans. In this respect, they contrast with blood-sucking species of mosquitoes. Toxorhynchites larvae live on a protein- and fat-rich diet of aquatic animals such as mosquito larvae. They have no need to risk their lives sucking blood in adulthood, having already accumulated the necessary materials for oogenesis and vitellogenesis.

Most species occur in forests. The larvae of one jungle variety, Toxorhynchites splendens, consume larvae of other mosquito species occurring in tree crevices, particularly Aedes aegypti.

Unlike Toxorhynchites mosquitoes, detritus feeder mosquito female larvae rely on blood meals to produce eggs more plentifully than a diet of nectar would permit. And even though blood sucking is a risky strategy that entails more casualties, and they could in principle subsist on nectar and the like as their males generally do, the risk is outweighed on average by the increase in the number and size of yolk-rich eggs that such protein-rich food permit.

Environmental scientists have suggested that Toxorhynchites mosquitoes be introduced to areas outside their natural range in order to fight dengue fever. This has been practiced historically, but errors have been made. For example, when intending to introduce T. splendens to new areas, scientists actually introduced T. amboinensis. An extinct species is known from Miocene aged Mexican Amber

🔗 Germany 🔗 Law Enforcement 🔗 Typography

The FE-Schrift or Fälschungserschwerende Schrift (forgery-impeding typeface) is a sans serif typeface introduced for use on licence plates. Its monospaced letters and numbers are slightly disproportionate to prevent easy modification and to improve machine readability. It has been developed in Germany where it has been mandatory since November 2000.

The abbreviation "FE" is derived from the compound German adjective "fälschungserschwerend" combining the noun "Fälschung" (falsification) and the verb "erschweren" (to hinder). "Schrift" means font in German. Other countries have later introduced the same or a derived typeface for license plates taking advantage of the proven design for the FE-Schrift.

🔗 Environment 🔗 Disaster management 🔗 London 🔗 Ecology 🔗 River Thames

The Great Stink was an event in central London in July and August 1858 during which the hot weather exacerbated the smell of untreated human waste and industrial effluent that was present on the banks of the River Thames. The problem had been mounting for some years, with an ageing and inadequate sewer system that emptied directly into the Thames. The miasma from the effluent was thought to transmit contagious diseases, and three outbreaks of cholera before the Great Stink were blamed on the ongoing problems with the river.

The smell, and fears of its possible effects, prompted action from the local and national administrators who had been considering possible solutions for the problem. The authorities accepted a proposal from the civil engineer Joseph Bazalgette to move the effluent eastwards along a series of interconnecting sewers that sloped towards outfalls beyond the metropolitan area. Work on high-, mid- and low-level systems for the new Northern and Southern Outfall Sewers started at the beginning of 1859 and lasted until 1875. To aid the drainage, pumping stations were placed to lift the sewage from lower levels into higher pipes. Two of the more ornate stations, Abbey Mills in Stratford and Crossness on the Erith Marshes, are listed for protection by English Heritage. Bazalgette's plan introduced the three embankments to London in which the sewers ran—the Victoria, Chelsea and Albert Embankments.

Bazalgette's work ensured that sewage was no longer dumped onto the shores of the Thames and brought an end to the cholera outbreaks; his actions are thought to have saved more lives than the efforts of any other Victorian official. His sewer system operates into the 21st century, servicing a city that has grown to a population of over eight million. The historian Peter Ackroyd argues that Bazalgette should be considered a hero of London.

🔗 Chemicals 🔗 Palaeontology 🔗 Geology 🔗 Evolutionary biology 🔗 Limnology and Oceanography 🔗 Project-independent assessment

The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust, or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era. Geological, isotopic, and chemical evidence suggests that biologically induced molecular oxygen (dioxygen, O₂) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere, causing almost all life on Earth to go extinct. The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.