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🔗 Biography 🔗 Russia 🔗 Mathematics 🔗 Biography/science and academia 🔗 Russia/science and education in Russia

Grigori Yakovlevich Perelman (Russian: Григорий Яковлевич Перельман, IPA: [ɡrʲɪˈɡorʲɪj ˈjakəvlʲɪvʲɪtɕ pʲɪrʲɪlʲˈman] (listen); born 13 June 1966) is a Russian mathematician who is known for his contributions to the fields of geometric analysis, Riemannian geometry, and geometric topology.

In the 1990s, partly in collaboration with Yuri Burago, Mikhael Gromov, and Anton Petrunin, he made influential contributions to the study of Alexandrov spaces. In 1994, he proved the soul conjecture in Riemannian geometry, which had been an open problem for the previous 20 years. In 2002 and 2003, he developed new techniques in the analysis of Ricci flow, thereby providing a detailed sketch of a proof of the Poincaré conjecture and Thurston's geometrization conjecture, the former of which had been a famous open problem in mathematics for the past century. The full details of Perelman's work were filled in and explained by various authors over the following several years.

In August 2006, Perelman was offered the Fields Medal for "his contributions to geometry and his revolutionary insights into the analytical and geometric structure of the Ricci flow", but he declined the award, stating: "I'm not interested in money or fame; I don't want to be on display like an animal in a zoo." On 22 December 2006, the scientific journal Science recognized Perelman's proof of the Poincaré conjecture as the scientific "Breakthrough of the Year", the first such recognition in the area of mathematics.

On 18 March 2010, it was announced that he had met the criteria to receive the first Clay Millennium Prize for resolution of the Poincaré conjecture. On 1 July 2010, he rejected the prize of one million dollars, saying that he considered the decision of the board of the Clay Institute to be unfair, in that his contribution to solving the Poincaré conjecture was no greater than that of Richard S. Hamilton, the mathematician who pioneered the Ricci flow partly with the aim of attacking the conjecture. He had previously rejected the prestigious prize of the European Mathematical Society, in 1996.

🔗 Literature 🔗 Poetry 🔗 Judaism 🔗 Christianity 🔗 Latter Day Saint movement 🔗 Christianity/Bible

Chiastic structure, or chiastic pattern, is a literary technique in narrative motifs and other textual passages. An example of chiastic structure would be two ideas, A and B, together with variants A' and B', being presented as A,B,B',A'. Chiastic structures that involve more components are sometimes called "ring structures", "ring compositions", or, in cases of very ambitious chiasmus, "onion-ring compositions". These may be regarded as chiasmus scaled up from words and clauses to larger segments of text.

These often symmetrical patterns are commonly found in ancient literature such as the epic poetry of the Iliad and the Odyssey. Classicist Bruno Gentili describes this technique as "the cyclical, circular, or 'ring' pattern (ring composition). Here the idea that introduced a compositional section is repeated at its conclusion, so that the whole passage is framed by material of identical content". Meanwhile, in classical prose, scholars often find chiastic narrative techniques in the Histories of Herodotus:

"Herodotus frequently uses ring composition or 'epic regression' as a way of supplying background information for something discussed in the narrative. First an event is mentioned briefly, then its precedents are reviewed in reverse chronological order as far back as necessary; at that point the narrative reverses itself and moves forward in chronological order until the event in the main narrative line is reached again."

Various chiastic structures are also seen in the Hebrew Bible, the New Testament, the Book of Mormon, and the Quran.

🔗 Computing 🔗 Caribbean 🔗 Caribbean/Aruba 🔗 Caribbean/Curaçao 🔗 Caribbean/Caribbean Netherlands

.an was the Internet country code top-level domain (ccTLD) for the former Netherlands Antilles. It was administered by the University of the Netherlands Antilles. The domain was phased out after the Netherlands Antilles were dissolved in 2010. As of November 2010 the .an domain remained live with over 800 domains registered under .an, including secondary levels. On 31 July 2015, use of the domain was discontinued.

🔗 France 🔗 Environment 🔗 Military history 🔗 Military history/World War I 🔗 Military history/French military history 🔗 Military history/European military history

The Zone Rouge (English: Red Zone) is a chain of non-contiguous areas throughout northeastern France that the French government isolated after the First World War. The land, which originally covered more than 1,200 square kilometres (460 sq mi), was deemed too physically and environmentally damaged by conflict for human habitation. Rather than attempt to immediately clean up the former battlefields, the land was allowed to return to nature. Restrictions within the Zone Rouge still exist today, although the control areas have been greatly reduced.

The Zone Rouge was defined just after the war as "Completely devastated. Damage to properties: 100%. Damage to Agriculture: 100%. Impossible to clean. Human life impossible".

Under French law, activities such as housing, farming, or forestry were temporarily or permanently forbidden in the Zone Rouge, because of the vast amounts of human and animal remains, and millions of items of unexploded ordnance contaminating the land. Some towns and villages were never permitted to be rebuilt after the war.

🔗 Companies 🔗 Finance & Investment

Renaissance Technologies LLC is an American hedge fund firm based in East Setauket, New York, on Long Island, which specializes in systematic trading using quantitative models derived from mathematical and statistical analyses. The firm is regarded as one of the "most secretive and successful" hedge funds in the world. Their signature Medallion fund is famed for the best record in investing history. Renaissance was founded in 1982 by James Simons, an award-winning mathematician and former Cold War code breaker.

In 1988, the firm established its most profitable portfolio, the Medallion Fund, which used an improved and expanded form of Leonard Baum's mathematical models, improved by algebraist James Ax, to explore correlations from which they could profit. Jim Berlekamp was instrumental in evolving trading to shorter-dated, pure systems driven decision-making. The hedge fund was named Medallion in honor of the math awards that Simons and Ax had won.

Renaissance's flagship Medallion fund, which is run mostly for fund employees, is famed for the best track record on Wall Street, returning more than 66 percent annualized before fees and 39 percent after fees over a 30-year span from 1988 to 2018. Renaissance offers two portfolios to outside investors—Renaissance Institutional Equities Fund (RIEF) and Renaissance Institutional Diversified Alpha (RIDA).

Simons ran Renaissance until his retirement in late 2009. The company is now run by Peter Brown (after Robert Mercer resigned). Both of them were computer scientists specializing in computational linguistics who joined Renaissance in 1993 from IBM Research. Simons continues to play a role at the firm as non-executive chairman and remains invested in its funds, particularly the secretive and consistently profitable black-box strategy known as Medallion. Because of the success of Renaissance in general and Medallion in particular, Simons has been described as the best money manager on earth.

🔗 Iceland 🔗 Lighthouses

Þrídrangaviti Lighthouse (transliterated as Thridrangaviti) is an active lighthouse 7.2 kilometres (4.5 miles) off the southwest coast of Iceland, in the archipelago of Vestmannaeyjar. It is often described as one of the most isolated lighthouses in the world. Þrídrangar means "three rock pillars", referring to the three named sea stacks at that location: Stóridrangur (on which the lighthouse stands), Þúfudrangur, and Klofadrangur. The lighthouse was commissioned on 5 July 1942.

🔗 Human rights 🔗 Medicine 🔗 Religion 🔗 Death 🔗 China 🔗 Religion/New religious movements 🔗 Religion/Falun Gong

Reports of forced organ harvesting from Falun Gong practitioners and other political prisoners in China have raised increasing concern within the international community. According to a report by former lawmaker David Kilgour, human rights campaigner David Matas and Victims of Communism Memorial Foundation researcher Ethan Gutmann, political prisoners, mainly Falun Gong practitioners, may be executed "on demand" in order to provide organs for transplant to recipients.

Reports on systematic organ harvesting from Falun Gong prisoners first emerged in 2006, though the practice is thought by some to have started six years earlier. Several researchers—most notably Matas, Kilgour and Gutmann—estimate that tens of thousands of Falun Gong prisoners of conscience have been killed to supply a lucrative trade in human organs and cadavers and that these abuses may be ongoing. These conclusions are based on a combination of statistical analysis; interviews with former prisoners, medical authorities and public security agents; and circumstantial evidence, such as the large number of Falun Gong practitioners detained extrajudicially in China and the profits to be made from selling organs.

The Chinese government long denied all accusations of organ harvesting. However, the failure of Chinese authorities to effectively address or refute the charges has drawn attention and public condemnation from some governments, international organizations and medical societies. The parliaments of Canada and the European Union, as well as the U.S. Senate and House of Representatives, have adopted resolutions condemning the forced organ harvesting from Falun Gong prisoners of conscience. United Nations Special Rapporteurs have called on the Chinese government to account for the sources of organs used in transplant practices, and the World Medical Association, the American Society of Transplantation and the Transplantation Society have called for sanctions on Chinese medical authorities. Several countries have also taken or considered measures to deter their citizens from travelling to China for the purpose of obtaining organs. A documentary on organ harvesting from Falun Gong practitioners, Human Harvest, received a 2014 Peabody Award recognizing excellence in broadcast journalism. China eventually admitted that it had engaged in systematic organ harvesting from death row prisoners, though it denies that such an organ harvesting program is ongoing.

🔗 Climate change 🔗 Environment 🔗 Antarctica 🔗 Glaciers

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.

🔗 Video games 🔗 Visual arts

The Atari Video Music (Model C240) is the earliest commercial electronic music visualizer released. It was manufactured by Atari, Inc., and released in 1977 for $169.95. The system creates an animated visual display that responds to musical input from a Hi-Fi stereo system for the visual entertainment of consumers.

🔗 Physics 🔗 Weather 🔗 Weather/Meteorological instruments and data

The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked cloth (a wet-bulb thermometer) over which air is passed. At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.

The wet-bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat supplied by the parcel. A wet-bulb thermometer indicates a temperature close to the true (thermodynamic) wet-bulb temperature. The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only.

Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C (90 °F), equivalent to a heat index of 55 °C (130 °F). The theoretical limit to human survival for more than a few hours in the shade, even with unlimited water, is a wet-bulb temperature of 35 °C (95 °F) – theoretically equivalent to a heat index of 70 °C (160 °F), though the heat index does not go that high.