Wikipedia:Main Page history/2012 October 21

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Today's featured article
A virus is a biological agent that reproduces inside the cells of living hosts. When infected, a host cell is forced to produce many thousands of identical copies of the original virus, at an extraordinary rate. Unlike most living things, viruses do not have cells that divide; new viruses are assembled in the infected host cell. Over 2,000 species of viruses have been discovered. A virus consists of two or three parts: genes, made from either DNA or RNA, long molecules that carry the genetic information; a protein coat that protects the genes; and in some, an envelope of fat that surrounds and protects them when they are not contained within a host cell. Viruses vary in shape from the simple helical and icosahedral to more complex structures. They spread in many different ways. Whereas viruses such as influenza are spread through the air by people when they cough or sneeze, others such as norovirus, which are transmitted by the faecal–oral route, contaminate hands, food and water. Rotavirus is often spread by direct contact with infected children. The human immunodeficiency virus, HIV, is one of several major viruses that are transmitted during sex. Viral infections often cause disease in humans and animals; however, they are usually eliminated by the immune system, conferring lifetime immunity to the host for that virus. (more...) Recently featured: Andjar Asmara – United States v. Wong Kim Ark – Sarah Churchill, Duchess of Marlborough Archive – By email – More featured articles...
Did you know...
From Wikipedia's newest content: ... that Karl-Friedrich Beringer conducted the Windsbacher Knabenchor (pictured), winner of the 2007 Rheingau Musikpreis, in Bach's St John Passion in Eberbach Abbey? ... that the Battle of Trafalgar is commemorated today in Gibraltar's Trafalgar Cemetery, where some of the casualties are buried? ... that Robert John Sholl, the only Resident Magistrate in north-west Western Australia between 1865 and 1883, had so much power that he was described as "virtually a Lieutenant Governor"? ... that the pharmocological products derived from the Spanish foxglove are up to three times more potent than those obtained from the common foxglove? ... that the Irish horror film Stitches marks the movie debut of English stand-up comedian Ross Noble as a homicidal undead clown? ... that the 2013 Manila mayoral election includes police officer Dirty Harry, gang leader Asiong Salonga, a fortune teller, a driver, and an engineer? Archive – Start a new article – Nominate an article

In the news
Guillaume, Hereditary Grand Duke of Luxembourg, marries Countess Stéphanie de Lannoy. Lebanese intelligence chief Wissam al-Hassan is assassinated in a car bomb attack in Beirut that kills four people and injures 110 others. The discovery of an Earth-sized planet (artist's impression pictured) in Alpha Centauri, the star system closest to Earth, is announced. Hilary Mantel wins the Man Booker Prize for the second time in four years for her novel Bring Up the Bodies. Pakistani child activist Malala Yousafzai, shot by a Taliban gunman last week, is sent to the United Kingdom for treatment. Syrian civil war – Wikinews – Recent deaths – More current events...
On this day...
October 21: Trafalgar Day in various Commonwealth countries 1520 – The islands of Saint Pierre and Miquelon (modern city of Saint-Pierre pictured) were discovered by Portuguese explorer João Álvares Fagundes near Canada, who named them "Islands of the 11,000 Virgins". 1854 – Florence Nightingale and a staff of 38 nurses were sent to Turkey to help treat wounded British soldiers fighting in the Crimean War. 1867 – The first of the Medicine Lodge Treaties was signed between the United States and several Native American tribes in the Great Plains, requiring them to relocate to areas in present-day western Oklahoma. 1950 – Korean War: British and Australian troops of the 27th British Commonwealth Brigade engaged in heavy fighting with North Korean forces in the Battle of Yongju. 1987 – Sri Lankan Civil War: Indian Army soldiers, belonging to the Indian Peace Keeping Force, entered the Jaffna Teaching Hospital in Jaffna, Sri Lanka, and began killing about 68–70 patients, nurses, doctors and other staff members. More anniversaries: October 20 – October 21 – October 22 Archive – By email – List of historical anniversaries It is now October 21, 2012 (UTC) – Refresh this page

Today's featured picture

The red rock crab (Grapsus grapsus) is one of the most common crabs along the western coast of the Americas. Adults are quite variable in color, including brownish-red, mottled or spotted brown, pink, yellow, bright orange and red. It feeds on algae primarily, sometimes sampling other plant matter and dead animals.

Photo: Lt. Elizabeth Crapo, NOAA Corps

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