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Antarctic Circumpolar Current
Dynamics
Dynamics The circumpolar current is driven by the strong westerly winds in the latitudes of the Southern Ocean. thumb|link=|The ACC (red circle near the middle of the image) in relation to the global thermohaline circulation [ (animation)] In latitudes where there are continents, winds blowing on light surface water can simply pile up light water against these continents. But in the Southern Ocean, the momentum imparted to the surface waters cannot be offset in this way. There are different theories on how the Circumpolar Current balances the momentum imparted by the winds. The increasing eastward momentum imparted by the winds causes water parcels to drift outward from the axis of the Earth's rotation (in other words, northward) as a result of the Coriolis force. This northward Ekman transport is balanced by a southward, pressure-driven flow below the depths of the major ridge systems. Some theories connect these flows directly, implying that there is significant upwelling of dense deep waters within the Southern Ocean, transformation of these waters into light surface waters, and a transformation of waters in the opposite direction to the north. Such theories link the magnitude of the Circumpolar Current with the global thermohaline circulation, particularly the properties of the North Atlantic. Alternatively, ocean eddies, the oceanic equivalent of atmospheric storms, or the large-scale meanders of the Circumpolar Current may directly transport momentum downward in the water column. This is because such flows can produce a net southward flow in the troughs and a net northward flow over the ridges without requiring any transformation of density. In practice both the thermohaline and the eddy/meander mechanisms are likely to be important. The current flows at a rate of about over the Macquarie Ridge south of New Zealand. The ACC varies with time. Evidence of this is the Antarctic Circumpolar Wave, a periodic oscillation that affects the climate of much of the southern hemisphere. There is also the Antarctic oscillation, which involves changes in the location and strength of Antarctic winds. Trends in the Antarctic Oscillation have been hypothesized to account for an increase in the transport of the Circumpolar Current over the past two decades.
Antarctic Circumpolar Current
Formation
Formation Published estimates of the onset of the Antarctic Circumpolar Current vary, but it is commonly considered to have started at the Eocene/Oligocene boundary. The isolation of Antarctica and formation of the ACC occurred with the openings of the Tasmanian Passage and the Drake Passage, following the fragmentation of the Antarctic land bridge. The Tasmanian Seaway separates East Antarctica and Australia, and is reported to have opened to water circulation 33.5 million years ago (Ma). The timing of the opening of the Drake Passage, between South America and the Antarctic Peninsula, is more disputed. Tectonic and sediment evidence show that it could have been open as early as pre-34 Ma; estimates of the opening of the Drake passage are between 20 and 40 Ma. The isolation of Antarctica by the current is credited by many researchers with causing the glaciation of Antarctica and global cooling in the Eocene epoch. Oceanic models have shown that the opening of these two passages limited polar heat convergence and caused a cooling of sea surface temperatures by several degrees; other models have shown that CO2 levels also played a significant role in the glaciation of Antarctica.
Antarctic Circumpolar Current
Phytoplankton
Phytoplankton thumb|The Falkland Current transports nutrient-rich cold waters from the ACC north toward the Brazil–Malvinas Confluence. Phytoplankton chlorophyll concentration are shown in blue (lower concentrations) and yellow (higher concentrations). Antarctic sea ice cycles seasonally, in February–March the amount of sea ice is lowest, and in August–September the sea ice is at its greatest extent. Ice levels have been monitored by satellite since 1973. Upwelling of deep water under the sea ice brings substantial amounts of nutrients. As the ice melts, the melt water provides stability and the critical depth is well below the mixing depth, which allows for a positive net primary production. As the sea ice recedes epontic algae dominate the first phase of the bloom, and a strong bloom dominate by diatoms follows the ice melt south. Another phytoplankton bloom occurs more to the north near the Antarctic Convergence, here nutrients are present from thermohaline circulation. Phytoplankton blooms are dominated by diatoms and grazed by copepods in the open ocean, and by krill closer to the continent. Diatom production continues through the summer, and populations of krill are sustained, bringing large numbers of cetaceans, cephalopods, seals, birds, and fish to the area. Phytoplankton blooms are believed to be limited by irradiance in the austral (southern hemisphere) spring, and by biologically available iron in the summer. Much of the biology in the area occurs along the major fronts of the current, the Subtropical, Subantarctic, and the Antarctic Polar fronts, these are areas associated with well defined temperature changes. Size and distribution of phytoplankton are also related to fronts. Microphytoplankton (>20 μm) are found at fronts and at sea ice boundaries, while nanophytoplankton (<20 μm) are found between fronts. Studies of phytoplankton stocks in the southern sea have shown that the Antarctic Circumpolar Current is dominated by diatoms, while the Weddell Sea has abundant coccolithophorids and silicoflagellates. Surveys of the SW Indian Ocean have shown phytoplankton group variation based on their location relative to the Polar Front, with diatoms dominating South of the front, and dinoflagellates and flagellates in higher populations North of the front. Some research has been conducted on Antarctic phytoplankton as a carbon sink. Areas of open water left from ice melt are good areas for phytoplankton blooms. The phytoplankton takes carbon from the atmosphere during photosynthesis. As the blooms die and sink, the carbon can be stored in sediments for thousands of years. This natural carbon sink is estimated to remove 3.5 million tonnes from the ocean each year. 3.5 million tonnes of carbon taken from the ocean and atmosphere is equivalent to 12.8 million tonnes of carbon dioxide.
Antarctic Circumpolar Current
Studies
Studies An expedition in May 2008 by 19 scientists studied the geology and biology of eight Macquarie Ridge sea mounts, as well as the Antarctic Circumpolar Current to investigate the effects of climate change of the Southern Ocean. The circumpolar current merges the waters of the Atlantic, Indian, and Pacific Oceans and carries up to 150 times the volume of water flowing in all of the world's rivers. The study found that any damage on the cold-water corals nourished by the current will have a long-lasting effect. After studying the circumpolar current it is clear that it strongly influences regional and global climate as well as underwater biodiversity. The subject has been characterized recently as "the spectral peak of the global extra-tropical circulation at ≈ 10^4 kilometers".Storer, B.A., Buzzicotti, M., Khatri, H. et al. Global energy spectrum of the general oceanic circulation. Nat Commun 13, 5314 (2022). https://doi.org/10.1038/s41467-022-33031-3. Retrieved 17 September 2022. The current helps preserve wooden shipwrecks by preventing wood-boring "ship worms" from reaching targets such as Ernest Shackleton's ship, the Endurance. The "State of the Cryosphere" report found, that the Antarctic Circumpolar Current became weaker. By 2050 it expected to lose 20% of its strength with "widespread impacts on ocean circulation and climate." The Weddell Sea Bottom Water has lost 30% of its volume in the latest 32 years, and the Antarctic Bottom Water is expected to shrink. This will impact ocean circulation, nutrients, heat content and carbon sequestration. UNESCO mentions that the report in the first time "notes a growing scientific consensus that melting Greenland and Antarctic ice sheets, among other factors, may be slowing important ocean currents at both poles, with potentially dire consequences for a much colder northern Europe and greater sea-level rise along the U.S. East Coast." The findings were bolstered by a 2025 study published in Environmental Research Letters.
Antarctic Circumpolar Current
References
References
Antarctic Circumpolar Current
Notes
Notes
Antarctic Circumpolar Current
Sources
Sources Category:Currents of the Southern Ocean Category:Geography of the Southern Ocean Category:Climate of Chile Category:Subantarctic
Antarctic Circumpolar Current
Table of Content
short description, Structure, Fronts, Dynamics, Formation, Phytoplankton, Studies, References, Notes, Sources
Arbor Day
short description
Arbor Day (or Arbour Day in some countries) is a secular day of observance in which individuals and groups are encouraged to plant trees. Today, many countries observe such a holiday. Though usually observed in the spring, the date varies, depending on climate and suitable planting season.
Arbor Day
Origins and history
Origins and history thumb|The naturalist Miguel Herrero Uceda at the monument to the first Arbor Day in the world, Villanueva de la Sierra (Spain), 1805
Arbor Day
First Arbor Day
First Arbor Day The Spanish village of Mondoñedo held the first documented arbor plantation festival in the world organized by its mayor in 1594. The place remains as Alameda de los Remedios and it is still planted with lime and horse-chestnut trees. A humble granite marker and a bronze plate recall the event. Additionally, the small Spanish village of Villanueva de la Sierra held the first modern Arbor Day, an initiative launched in 1805 by the local priest with the enthusiastic support of the entire population.
Arbor Day
First American Arbor Day
First American Arbor Day thumb|Birdsey Northrop The first American Arbor Day was originated by J. Sterling Morton of Nebraska City, Nebraska, at an annual meeting of the Nebraska State board of agriculture held in Lincoln. On April 10, 1872, an estimated one million trees were planted in Nebraska. In 1883, the American Forestry Association made Birdsey Northrop of Connecticut the chairman of the committee to campaign for Arbor Day nationwide; Northrop further globalized the idea when he visited Japan in 1895 and delivered his Arbor Day and Village Improvement message. He also brought his enthusiasm for Arbor Day to Australia, Canada, and other countries in Europe.
Arbor Day
McCreight and Theodore Roosevelt
McCreight and Theodore Roosevelt Beginning in 1906, Pennsylvania conservationist Major Israel McCreight of DuBois, Pennsylvania, argued that President Theodore Roosevelt's conservation speeches were limited to businessmen in the lumber industry and recommended a campaign of youth education and a national policy on conservation education.M.I. McCreight, Theodore Roosevelt and Conservation Why: A Thirty-Four Year Moratorium on Unpublished Records (1940), Historical Society of Western Pennsylvania, at p.12, Hereinafter cited "Theodore Roosevelt and Conservation Why". McCreight urged Roosevelt to make a public statement to school children about trees and the destruction of American forests. Conservationist Gifford Pinchot, Chief of the United States Forest Service, embraced McCreight's recommendations and asked the President to speak to the public school children of the United States about conservation. On April 15, 1907, Roosevelt issued an "Arbor Day Proclamation to the School Children of the United States" about the importance of trees and that forestry deserves to be taught in U.S. schools. Pinchot wrote McCreight, "we shall all be indebted to you for having made the suggestion.""Theodore Roosevelt and Conservation Why"
Arbor Day
Around the world
Around the world thumb|right|Arbor Day in Algeria
Arbor Day
Australia
Australia Arbor Day has been observed in Australia since the first event took place in Adelaide, South Australia on the 20th June 1889. National Schools Tree Day is held on the last Friday of July for schools and National Tree Day the last Sunday in July throughout Australia. Many states have Arbour Day, although Victoria has an Arbour Week, which was suggested by Premier Rupert (Dick) Hamer in the 1980s.
Arbor Day
Belgium
Belgium International Day of Treeplanting is celebrated in Flanders on or around 21 March as a theme-day/educational-day/observance, not as a public holiday. Tree planting is sometimes combined with awareness campaigns of the fight against cancer: Kom Op Tegen Kanker.
Arbor Day
Brazil
Brazil The Arbor Day (Dia da Árvore) is celebrated on September 21. It is not a national holiday. However, schools nationwide celebrate this day with environment-related activities, namely tree planting.
Arbor Day
British Virgin Islands
British Virgin Islands Arbour Day is celebrated on November 22. It is sponsored by the National Parks Trust of the Virgin Islands. Activities include an annual national Arbour Day Poetry Competition and tree planting ceremonies throughout the territory.
Arbor Day
Cambodia
Cambodia Cambodia celebrates Arbor Day on July 9 with a tree planting ceremony attended by the king.
Arbor Day
Canada
Canada The day was founded by Sir George William Ross, later the premier of Ontario, when he was minister of education in Ontario (1883–1899). According to the Ontario Teachers' Manuals "History of Education" (1915), Ross established both Arbour Day and Empire Day—"the former to give the school children an interest in making and keeping the school grounds attractive, and the latter to inspire the children with a spirit of patriotism" (p. 222). This predates the claimed founding of the day by Don Clark of Schomberg, Ontario for his wife Margret Clark in 1906. In Canada, National Forest Week is the last full week of September, and National Tree Day (Maple Leaf Day) falls on the Wednesday of that week. Ontario celebrates Arbour Week from the last Friday in April to the first Sunday in May. Prince Edward Island celebrates Arbour Day on the third Friday in May during Arbour Week. Arbour Day is the longest running civic greening project in Calgary and is celebrated on the first Thursday in May. On this day, each grade 1 student in Calgary's schools receives a tree seedling to be taken home to be planted on private property.
Arbor Day
Central African Republic
Central African Republic National Tree Planting Day is on July 22.
Arbor Day
Chile
Chile "Dia del Arbol" was celebrated on June 28, 2022, as defined by Chile's Environment Ministry
Arbor Day
Greater China
Greater China
Arbor Day
Republic of China (Taiwan)
Republic of China (Taiwan) Arbor Day (植樹節) was founded by the forester Ling Daoyang in 1915 and has been a traditional holiday in the Republic of China since 1916. The Beiyang government's Ministry of Agriculture and Commerce first commemorated Arbor Day in 1915 at the suggestion of forester Ling Daoyang. In 1916, the government announced that all provinces of the Republic of China would celebrate the on the same day as the Qingming Festival, April 5, despite the differences in climate across China, which is on the first day of the fifth solar term of the traditional Chinese lunisolar calendar. From 1929, by decree of the Nationalist government, Arbor Day was , to commemorate the death of Sun Yat-sen, who had been a major advocate of afforestation in his life. Following the retreat of the government of the Republic of China to Taiwan in 1949, the celebration of Arbor Day on March 12 was retained.
Arbor Day
People's Republic of China
People's Republic of China In People's Republic of China, during the fourth session of the Fifth National People's Congress of the People's Republic of China in 1979 adopted the Resolution on the Unfolding of a Nationwide Voluntary Tree-planting Campaign. This resolution established the Arbor Day (植树节), also March 12, and stipulated that every able-bodied citizen between the ages of 11 and 60 should plant three to five trees per year or do the equivalent amount of work in seedling, cultivation, tree tending, or other services. Supporting documentation instructs all units to report population statistics to the local afforestation committees for workload allocation. Many couples choose to marry the day before the annual celebration, and they plant the tree to mark beginning of their life together and the new life of the tree.
Arbor Day
Republic of Congo
Republic of Congo National Tree Planting Day is on November 6.
Arbor Day
Costa Rica
Costa Rica "Día del Árbol" is on June 15.
Arbor Day
Colombia
Colombia "Día de los Árboles" (Day of Trees) is on April 29.
Arbor Day
Cuba
Cuba "Dia del Árbol" (Day of the Tree) was first observed on October 10, 1904, and today is officially observed on June 21 of each year.
Arbor Day
Czech Republic
Czech Republic Arbor Day in the Czech Republic is celebrated on October 20.
Arbor Day
Egypt
Egypt Arbor Day is on January 15.
Arbor Day
Germany
Germany Arbor Day ("Tag des Baumes") is on April 25. Its first celebration was in 1952.
Arbor Day
India
India Van Mahotsav is an annual pan-Indian tree planting festival, occupying a week in the month of July. During this event millions of trees are planted. It was initiated in 1950 by K. M. Munshi, the then Union Minister for Agriculture and Food, to create an enthusiasm in the mind of the populace for the conservation of forests and planting of trees. The name Van Mahotsava (the festival of trees) originated in July 1947 after a successful tree-planting drive was undertaken in Delhi, in which national leaders like Jawaharlal Nehru, Dr Rajendra Prasad and Abul Kalam Azad participated. Paryawaran Sachetak Samiti, a leading environmental organization conducts mass events and activities on this special day celebration each year. The week was simultaneously celebrated in a number of states in the country.
Arbor Day
Iran
Iran alt=Tree planting ceremony in Persia, Tehran|thumb|Tree planting ceremony in Persia, Tehran In Iran, it is known as "National Tree Planting Day". By the Solar Hijri calendar, it is on the fifteenth day of the month Esfand, which usually corresponds with March 5. This day is the first day of the "Natural Recyclable Resources Week" (March 5 to 12). This is the time when the saplings of the all kinds in terms of different climates of different parts of Iran are shared among the people. They are also taught how to plant trees.
Arbor Day
Israel
Israel thumb|right|Tu Bishvat, Israel The Jewish holiday Tu Bishvat, the new year for trees, is on the 15th day of the month of Shvat, which usually falls in January or February. Originally based on the date used to calculate the age of fruit trees for tithing as mandated in Leviticus 19:23–25, the holiday now is most often observed by planting trees or raising money to plant trees,Judaism 101: Tu B'Shevat. Accessed August 20, 2007. and by eating dried fruits, specifically Raisins, figs, dates and nuts. Tu Bishvat is a semi-official holiday in Israel; schools are open but Hebrew-speaking schools often go on tree-planting excursions.
Arbor Day
Japan
Japan Japan celebrates a similarly themed Greenery Day, held on May 4.
Arbor Day
Kenya
Kenya Historically, Kenya celebrated National Tree Planting Day on April 21. Often people plant palm trees and coconut trees along the Indian Ocean that borders the east coast of Kenya. They plant trees to remember Prof. Wangari Maathai, who won a Nobel Peace Prize for planting of trees and caring for them all over Kenya. With the Kenyan government launching a campaign to plant 15 billion trees by 2032, they launched National Tree Growing Day with very aggressive targets for the number of trees to be planted. The first national public holiday was November 13, 2023. The second was May 10, 2024, with a goal to plant one billion trees in a single day.
Arbor Day
Korea
Korea North Korea marks "Tree Planting Day" on March 2, when people across the country plant trees. This day is considered to combine traditional Asian cultural values with the country's dominant Communist ideology.Tree-planting Day Marked in DPRK In South Korea, April 5, Singmogil or Sikmogil (식목일), the Arbor Day, was a public holiday until 2005. Even though Singmogil is no longer an official holiday, the day is still celebrated, with the South Korean public continuing to take part in tree-planting activities.
Arbor Day
Lesotho
Lesotho National Tree Planting Day is usually on March 21 depending on the lunar cycle.
Arbor Day
Luxembourg
Luxembourg National Tree Planting Day is on the second Saturday in November.
Arbor Day
Malawi
Malawi National Tree Planting Day is on the 2nd Monday of December.
Arbor Day
Mexico
Mexico thumbnail|President Enrique Peña Nieto plants a tree in Balleza, Chihuahua to commemorate the Día del Árbol 2013. The Día del Árbol was established in Mexico in 1959 with President Adolfo López Mateos issuing a decree that it should be observed on the 2nd Thursday of July.
Arbor Day
Mongolia
Mongolia National Tree Planting Day is on the 2nd Saturday of May and October. The first National Tree Planting Day was celebrated May 8, 2010.
Arbor Day
Namibia
Namibia Namibia's first Arbor Day was celebrated on October 8, 2004. It takes place annually on the second Friday of October.
Arbor Day
Netherlands
Netherlands Since conference and of the Food and Agriculture Organization's publication World Festival of Trees, and a resolution of the United Nations in 1954: "The Conference, recognising the need of arousing mass consciousness of the aesthetic, physical and economic value of trees, recommends a World Festival of Trees to be celebrated annually in each member country on a date suited to local conditions"; it has been adopted by the Netherlands. In 1957, the National Committee Day of Planting Trees/Foundation of National Festival of Trees (Nationale Boomplantdag/Nationale Boomfeestdag) was created. On the third Wednesday in March each year (near the spring equinox), three quarters of Dutch schoolchildren aged 10/11 and Dutch celebrities plant trees. Stichting Nationale Boomfeestdag organizes all the activities in the Netherlands for this day. Some municipalities however plant the trees around 21 September because of the planting season.Boomfeestdag http://www.boomfeestdag.nl/ the organisations address is Spoorlaan 444 5038 CH TILBURG In 2007, the 50th anniversary was celebrated with special golden jubilee activities.
Arbor Day
New Zealand
New Zealand New Zealand's first Arbor Day planting was on 3 July 1890 at Greytown, in the Wairarapa. The first official celebration was scheduled to take place in Wellington in August 1892, with the planting of pōhutukawa and Norfolk pines along Thorndon Esplanade. Prominent New Zealand botanist Dr Leonard Cockayne worked extensively on native plants throughout New Zealand and wrote many notable botanical texts. As early as the 1920s he held a vision for school students of New Zealand to be involved in planting native trees and plants in their school grounds. This vision bore fruit and schools in New Zealand have long planted native trees on Arbor Day. Since 1977, New Zealand has celebrated Arbor Day on 5 June, which is also World Environment Day. Prior to then, Arbor Day was celebrated on 4 August, which is rather late in the year for tree planting in New Zealand, hence the date change. Many of the Department of Conservation's Arbor Day activities focus on ecological restoration projects using native plants to restore habitats that have been damaged or destroyed by humans or invasive pests and weeds. There are great restoration projects underway around New Zealand and many organisations including community groups, landowners, conservation organisations, iwi, volunteers, schools, local businesses, nurseries and councils are involved in them. These projects are part of a vision to protect and restore the indigenous biodiversity.
Arbor Day
Niger
Niger Since 1975, Niger has celebrated Arbor Day as part of its Independence Day: 3 August. On this day, aiding the fight against desertification, each Nigerien plants a tree.
Arbor Day
North Macedonia
North Macedonia Having in mind the bad condition of the forest fund, and in particular the catastrophic wildfires which occurred in the summer of 2007, a citizens' initiative for afforestation was started in North Macedonia. The campaign by the name 'Tree Day-Plant Your Future' was first organized on 12 March 2008, when an official non-working day was declared and more than 150,000 Macedonians planted 2 million trees in one day (symbolically, one for each citizen). Six million more were planted in November the same year, and another 12,5 million trees in 2009. This has been established as a tradition and takes place every year.
Arbor Day
Pakistan
Pakistan National tree plantation day of Pakistan (قومی شجر کاری دن) is celebrated on 18 August.
Arbor Day
Philippines
Philippines Since 1947, Arbor Day in the Philippines has been institutionalized to be observed throughout the nation by planting trees and ornamental plants and other forms of relevant activities. Its practice was instituted through Proclamation No. 30. It was subsequently revised by Proclamation No. 41, issued in the same year. In 1955, the commemoration was extended from a day to a week and moved to the last full week of July. Over two decades later, its commemoration was moved to the second week of June. In 2003, the commemorations were reduced from a week to a day and was moved to June 25 per Proclamation No. 396. The same proclamation directed "the active participation of all government agencies, including government-owned and controlled corporations, private sector, schools, civil society groups and the citizenry in tree planting activity". It was subsequently revised by Proclamation 643 in the succeeding year. In 2012, Republic Act 10176 was passed, which revived tree planting events "as [a] yearly event for local government units" and mandated the planting of at least one tree per year for able-bodied Filipino citizens aged 12 years old and above. Since 2012, many local arbor day celebrations have been commemorated, as in the cases of Natividad and Tayug in Pangasinan and Santa Rita in Pampanga.
Arbor Day
Poland
Poland In Poland, Arbor Day has been celebrated since 2002. Each October 10, many Polish people plant trees as well as participate in events organized by ecological foundations. Moreover, Polish Forest Inspectorates and schools give special lectures and lead ecological awareness campaigns.
Arbor Day
Portugal
Portugal Arbor Day is celebrated on March 21. It is not a national holiday but instead schools nationwide celebrate this day with environment-related activities, namely tree planting.
Arbor Day
Russia
Russia All-Russian day of forest plantation was celebrated for the first time on 14 May 2011. Now it is held in April–May (it depends on the weather in different regions).
Arbor Day
Samoa
Samoa Arbor Day in Samoa is celebrated on the first Friday in November.
Arbor Day
Saudi Arabia
Saudi Arabia Arbor Day in Saudi Arabia is celebrated on April 29.
Arbor Day
Singapore
Singapore In 1971 a 'Tree Planting Day' was established which in 1990 was replaced by 'Clean and Green Week'.
Arbor Day
South Africa
South Africa Arbor Day was celebrated from 1945 until 2000 in South Africa. After that, the national government extended it to National Arbor Week, which lasts annually from 1–7 September. Two trees, one common and one rare, are highlighted to increase public awareness of indigenous trees, while various "greening" activities are undertaken by schools, businesses and other organizations. For example, the social enterprise Greenpop, which focusses on sustainable urban greening, forest restoration and environmental awareness in Sub-Saharan Africa,Greenpop. "It's a TREEvolution. Retrieved on 25 March 2020. leverages Arbor Day each year to call for tree planting action. During Arbor Month 2019, responding to recent studies that underscore the importance of tree restoration, they launched their new goal of planting 500,000 by 2025.The Ecologist. "Arbor month in South Africa., 2 September 2019. Retrieved on 25 March 2020.Greenpop. "Plant trees, save the world!, 22 August 2019. Retrieved on 25 March 2020.
Arbor Day
Spain
Spain thumb|Planting holm oaks in Pescueza In 1896 Mariano Belmás Estrada promoted the first "Festival of Trees" in Madrid. In Spain there was an International Forest Day on 21 March, but a decree in 1915 also brought in an Arbor Day throughout Spain. Each municipality or collective decides the date for its Arbor Day, usually between February and May. In Villanueva de la Sierra (Extremadura), where the first Arbor Day in the world was held in 1805, it is celebrated, as on that occasion, on Tuesday Carnaval. It is a great day in the local festive calendar.The oldest environmentalist festival in the world was celebrated in Villanueva. Sierra de Gata News. February 26, 2014 As an example of commitment to nature, the small town of Pescueza, with only 180 inhabitants, organizes every spring a large plantation of holm oaks, which is called the "Festivalino", promoted by city council, several foundations, and citizen participation.Herrero Uceda, Miguel y Elisa: Mi Extremadura. 2011, pages 147-148
Arbor Day
Sri Lanka
Sri Lanka National Tree Planting Day is on November 15.
Arbor Day
Tanzania
Tanzania National Tree Planting Day is on April 1.
Arbor Day
Turkey
Turkey National Tree Planting Day is on November 11.
Arbor Day
Uganda
Uganda National Tree Planting Day is on March 24.
Arbor Day
United Kingdom
United Kingdom First mounted in 1975, National Tree Week is a celebration of the start of the winter tree planting season, usually at the end of November. Around a million trees are planted each year by schools, community organizations and local authorities. On 6 February 2020, Myerscough College in Lancashire, England, supported by the Arbor Day Foundation, celebrated the UK's first Arbor Day. thumb|Arbor Day community festival in Rochester, Minnesota
Arbor Day
United States
United States Arbor Day was founded in 1872 by J. Sterling Morton in Nebraska City, Nebraska. By the 1920s, each state in the United States had passed public laws that stipulated a certain day to be Arbor Day or Arbor and Bird Day observance. National Arbor Day is celebrated every year on the last Friday in April; it is a civic holiday in Nebraska. Other states have selected their own dates for Arbor Day. The customary observance is to plant a tree. On the first Arbor Day, April 10, 1872, an estimated one million trees were planted."The History of Arbor Day" at the Arbor Day Foundation. Accessed on April 26, 2013.
Arbor Day
Venezuela
Venezuela Venezuela recognizes Día del Arbol (Day of the Tree) on the last Sunday of May.
Arbor Day
See also
See also Arbor Day Foundation (US) Earth Day Greenery Day (Japan) International Day of Forests National Public Lands Day (US) Timeline of environmental events Tu BiShvat (Jewish holiday) World Water Day
Arbor Day
References
References
Arbor Day
External links
External links International Arbor Days Arbor Day lesson plans for the classroom National Arbor Day Foundation State Arbor Days and state trees History of Arbor Day Category:Environmental awareness days Category:Trees in culture Category:1872 establishments in Nebraska Category:Recurring events established in 1872 Category:Urban forestry Category:Reforestation Category:Types of secular holidays Category:Forestry events Category:Holidays and observances by scheduling (nth weekday of the month) Category:Forestry-related lists
Arbor Day
Table of Content
short description, Origins and history, First Arbor Day, First American Arbor Day, McCreight and Theodore Roosevelt, Around the world, Australia, Belgium, Brazil, British Virgin Islands, Cambodia, Canada, Central African Republic, Chile, Greater China, Republic of China (Taiwan), People's Republic of China, Republic of Congo, Costa Rica, Colombia, Cuba, Czech Republic, Egypt, Germany, India, Iran, Israel, Japan, Kenya, Korea, Lesotho, Luxembourg, Malawi, Mexico, Mongolia, Namibia, Netherlands, New Zealand, Niger, North Macedonia, Pakistan, Philippines, Poland, Portugal, Russia, Samoa, Saudi Arabia, Singapore, South Africa, Spain, Sri Lanka, Tanzania, Turkey, Uganda, United Kingdom, United States, Venezuela, See also, References, External links
A. J. Ayer
short description
Sir Alfred Jules "Freddie" Ayer ( ;"Ayer". Random House Webster's Unabridged Dictionary. 29 October 1910 – 27 June 1989) was an English philosopher known for his promotion of logical positivism, particularly in his books Language, Truth, and Logic (1936) and The Problem of Knowledge (1956). Ayer was educated at Eton College and the University of Oxford, after which he studied the philosophy of logical positivism at the University of Vienna. From 1933 to 1940 he lectured on philosophy at Christ Church, Oxford. During the Second World War Ayer was a Special Operations Executive and MI6 agent. Ayer was Grote Professor of the Philosophy of Mind and Logic at University College London from 1946 until 1959, after which he returned to Oxford to become Wykeham Professor of Logic at New College. He was president of the Aristotelian Society from 1951 to 1952 and knighted in 1970. He was known for his advocacy of humanism, and was the second president of the British Humanist Association (now known as Humanists UK). Ayer was president of the Homosexual Law Reform Society for a time; he remarked, "as a notorious heterosexual I could never be accused of feathering my own nest."
A. J. Ayer
Life
Life Ayer was born in St John's Wood, in north west London, to Jules Louis Cyprien Ayer and Reine (née Citroen), wealthy parents from continental Europe. His mother was from the Dutch-Jewish family that founded the Citroën car company in France; his father was a Swiss Calvinist financier who worked for the Rothschild family, including for their bank and as secretary to Alfred Rothschild.Anthony Quinton, Alfred Jules Ayer. Proceedings of the British Academy, 94 (1996), pp. 255–282. Ayer was educated at Ascham St Vincent's School, a former boarding preparatory school for boys in the seaside town of Eastbourne in Sussex, where he started boarding at the relatively early age of seven for reasons to do with the First World War, and at Eton College, where he was a King's Scholar. At Eton Ayer first became known for his characteristic bravado and precocity. Though primarily interested in his intellectual pursuits, he was very keen on sports, particularly rugby, and reputedly played the Eton Wall Game very well. In the final examinations at Eton, Ayer came second in his year, and first in classics. In his final year, as a member of Eton's senior council, he unsuccessfully campaigned for the abolition of corporal punishment at the school. He won a classics scholarship to Christ Church, Oxford. He graduated with a BA with first-class honours. After graduating from Oxford, Ayer spent a year in Vienna, returned to England and published his first book, Language, Truth and Logic, in 1936. This first exposition in English of logical positivism as newly developed by the Vienna Circle, made Ayer at age 26 the enfant terrible of British philosophy. As a newly famous intellectual, he played a prominent role in the Oxford by-election campaign of 1938. Ayer campaigned first for the Labour candidate Patrick Gordon Walker, and then for the joint Labour-Liberal "Independent Progressive" candidate Sandie Lindsay, who ran on an anti-appeasement platform against the Conservative candidate, Quintin Hogg, who ran as the appeasement candidate. The by-election, held on 27 October 1938, was quite close, with Hogg winning narrowly. In the Second World War, Ayer served as an officer in the Welsh Guards, chiefly in intelligence (Special Operations Executive (SOE) and MI6). He was commissioned as a second lieutenant into the Welsh Guards from the Officer Cadet Training Unit on 21 September 1940. After the war, Ayer briefly returned to the University of Oxford where he became a fellow and Dean of Wadham College. He then taught philosophy at University College London from 1946 until 1959, during which time he started to appear on radio and television. He was an extrovert and social mixer who liked dancing and attending clubs in London and New York. He was also obsessed with sport: he had played rugby for Eton, and was a noted cricketer and a keen supporter of Tottenham Hotspur football team, where he was for many years a season ticket holder.Radio Times article by Tim Heald, 20–26 August 1977 For an academic, Ayer was an unusually well-connected figure in his time, with close links to 'high society' and the establishment. Presiding over Oxford high-tables, he is often described as charming, but could also be intimidating. Ayer was married four times to three women. His first marriage was from 1932 to 1941, to (Grace Isabel) Renée, with whom he had a sonallegedly the son of Ayer's friend and colleague Stuart Hampshireand a daughter. Renée subsequently married Hampshire. In 1960, Ayer married Alberta Constance (Dee) Wells, with whom he had one son. That marriage was dissolved in 1983, and the same year, Ayer married Vanessa Salmon, the former wife of politician Nigel Lawson. She died in 1985, and in 1989 Ayer remarried Wells, who survived him. He also had a daughter with Hollywood columnist Sheilah Graham Westbrook. In 1950, Ayer attended the founding meeting of the Congress for Cultural Freedom in West Berlin, though he later said he went only because of the offer of a "free trip". He gave a speech on why John Stuart Mill's conceptions of liberty and freedom were still valid in the 20th century. Together with the historian Hugh Trevor-Roper, Ayer fought against Arthur Koestler and Franz Borkenau, arguing that they were far too dogmatic and extreme in their anti-communism, in fact proposing illiberal measures in the defence of liberty. Adding to the tension was the location of the congress in West Berlin, together with the fact that the Korean War began on 25 June 1950, the fourth day of the congress, giving a feeling that the world was on the brink of war. From 1959 to his retirement in 1978, Ayer held the Wykeham Chair, Professor of Logic at Oxford. He was knighted in 1970. After his retirement, Ayer taught or lectured several times in the United States, including as a visiting professor at Bard College in 1987. At a party that same year held by fashion designer Fernando Sanchez, Ayer confronted Mike Tyson, who was forcing himself upon the then little-known model Naomi Campbell. When Ayer demanded that Tyson stop, Tyson reportedly asked, "Do you know who the fuck I am? I'm the heavyweight champion of the world", to which Ayer replied, "And I am the former Wykeham Professor of Logic. We are both pre-eminent in our field. I suggest that we talk about this like rational men". Ayer and Tyson then began to talk, allowing Campbell to slip out.Rogers (1999), p. 344. Gully Wells, Ayer's stepdaughter via Dee Wells, records the same event with some slight variation of detail. Ayer was also involved in politics, including anti-Vietnam War activism, supporting the Labour Party (and later the Social Democratic Party), chairing the Campaign Against Racial Discrimination in Sport, and serving as president of the Homosexual Law Reform Society. In 1988, a year before his death, Ayer wrote an article titled "What I saw when I was dead", describing an unusual near-death experience after his heart stopped for four minutes as he choked on smoked salmon.Ayer, A. J. (28 August 1988). "What I Saw When I Was Dead". The Sunday Telegraph. Reprinted as "The Undiscovered Country" in The Meaning Of Life (1990) and The Philosophy of A. J. Ayer (1992) Of the experience, he first said that it "slightly weakened my conviction that my genuine death ... will be the end of me, though I continue to hope that it will be." A few weeks later, he revised this, saying, "what I should have said is that my experiences have weakened, not my belief that there is no life after death, but my inflexible attitude towards that belief".Ayer, A. J. (15 October 1988). "Postscript to a Postmortem". The Spectator. Archived from the original on 12 March 2018. Reprinted in The Meaning Of Life (1990) and The Philosophy of A. J. Ayer (1992) Ayer died on 27 June 1989. From 1980 to 1989 he lived at 51 York Street, Marylebone, where a memorial plaque was unveiled on 19 November 1995.
A. J. Ayer
Philosophical ideas
Philosophical ideas In Language, Truth and Logic (1936), Ayer presents the verification principle as the only valid basis for philosophy. Unless logical or empirical verification is possible, statements like "God exists" or "charity is good" are not true or untrue but meaningless, and may thus be excluded or ignored. Religious language in particular is unverifiable and as such literally nonsense. He also criticises C. A. Mace's opinion"Representation and Expression," Analysis, Vol. 1, No. 3; "Metaphysics and Emotive Language," Analysis Vol. II, nos. 1 and 2, that metaphysics is a form of intellectual poetry.Ayer A.J. Language, Truth and Logic 1946/1952, New York/Dover The stance that a belief in God denotes no verifiable hypothesis is sometimes referred to as igtheism (for example, by Paul Kurtz). In later years, Ayer reiterated that he did not believe in God"I do not believe in God. It seems to me that theists of all kinds have very largely failed to make their concept of a deity intelligible; and to the extent that they have made it intelligible, they have given us no reason to think that anything answers to it." Ayer, A.J. (1966). "What I Believe," Humanist, Vol. 81 (8) August, p. 226. and began to call himself an atheist."I trust that my remaining an atheist will allay the anxieties of my fellow supporters of the British Humanist Association, the Rationalist Press Association and the South Place Ethical Society." (Ayer 1989, p. 12) He followed in the footsteps of Bertrand Russell by debating religion with the Jesuit scholar Frederick Copleston. Ayer's version of emotivism divides "the ordinary system of ethics" into four classes: "Propositions that express definitions of ethical terms, or judgements about the legitimacy or possibility of certain definitions" "Propositions describing the phenomena of moral experience, and their causes" "Exhortations to moral virtue" "Actual ethical judgements" He focuses on propositions of the first classmoral judgementssaying that those of the second class belong to science, those of the third are mere commands, and those of the fourth (which are considered normative ethics as opposed to meta-ethics) are too concrete for ethical philosophy. Ayer argues that moral judgements cannot be translated into non-ethical, empirical terms and thus cannot be verified; in this he agrees with ethical intuitionists. But he differs from intuitionists by discarding appeals to intuition of non-empirical moral truths as "worthless" since the intuition of one person often contradicts that of another. Instead, Ayer concludes that ethical concepts are "mere pseudo-concepts": Between 1945 and 1947, together with Russell and George Orwell, Ayer contributed a series of articles to Polemic, a short-lived British Magazine of Philosophy, Psychology, and Aesthetics edited by the ex-Communist Humphrey Slater. Ayer was closely associated with the British humanist movement. He was an Honorary Associate of the Rationalist Press Association from 1947 until his death. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1963. In 1965, he became the first president of the Agnostics' Adoption Society and in the same year succeeded Julian Huxley as president of the British Humanist Association, a post he held until 1970. In 1968 he edited The Humanist Outlook, a collection of essays on the meaning of humanism. He was one of the signers of the Humanist Manifesto.
A. J. Ayer
Works
Works Ayer is best known for popularising the verification principle, in particular through his presentation of it in Language, Truth, and Logic. The principle was at the time at the heart of the debates of the so-called Vienna Circle, which Ayer had visited as a young guest. Others, including the circle's leading light, Moritz Schlick, were already writing papers on the issue. Ayer's formulation was that a sentence can be meaningful only if it has verifiable empirical import; otherwise, it is either "analytical" if tautologous or "metaphysical" (i.e. meaningless, or "literally senseless"). He started to work on the book at the age of 23Language, Truth and Logic, Penguin, 2001, p. ix and it was published when he was 26. Ayer's philosophical ideas were deeply influenced by those of the Vienna Circle and David Hume. His clear, vibrant and polemical exposition of them makes Language, Truth and Logic essential reading on the tenets of logical empiricism; the book is regarded as a classic of 20th-century analytic philosophy and is widely read in philosophy courses around the world. In it, Ayer also proposes that the distinction between a conscious man and an unconscious machine resolves itself into a distinction between "different types of perceptible behaviour",Language, Truth and Logic, Penguin, 2001, p. 140 an argument that anticipates the Turing test published in 1950 to test a machine's capability to demonstrate intelligence. Ayer wrote two books on the philosopher Bertrand Russell, Russell and Moore: The Analytic Heritage (1971) and Russell (1972). He also wrote an introductory book on the philosophy of David Hume and a short biography of Voltaire. Ayer was a strong critic of the German philosopher Martin Heidegger. As a logical positivist, Ayer was in conflict with Heidegger's vast, overarching theories of existence. Ayer considered them completely unverifiable through empirical demonstration and logical analysis, and this sort of philosophy an unfortunate strain in modern thought. He considered Heidegger the worst example of such philosophy, which Ayer believed entirely useless. In Philosophy in the Twentieth Century, Ayer accuses Heidegger of "surprising ignorance" or "unscrupulous distortion" and "what can fairly be described as charlatanism." In 1972–73, Ayer gave the Gifford Lectures at the University of St Andrews, later published as The Central Questions of Philosophy. In the book's preface, he defends his selection to hold the lectureship on the basis that Lord Gifford wished to promote "natural theology, in the widest sense of that term", and that non-believers are allowed to give the lectures if they are "able reverent men, true thinkers, sincere lovers of and earnest inquirers after truth". He still believed in the viewpoint he shared with the logical positivists: that large parts of what was traditionally called philosophyincluding metaphysics, theology and aestheticswere not matters that could be judged true or false, and that it was thus meaningless to discuss them. In The Concept of a Person and Other Essays (1963), Ayer heavily criticised Wittgenstein's private language argument. Ayer's sense-data theory in Foundations of Empirical Knowledge was famously criticised by fellow Oxonian J. L. Austin in Sense and Sensibilia, a landmark 1950s work of ordinary language philosophy. Ayer responded in the essay "Has Austin Refuted the Sense-datum Theory?", which can be found in his Metaphysics and Common Sense (1969).
A. J. Ayer
Awards
Awards Ayer was awarded a knighthood as Knight Bachelor in the London Gazette on 1 January 1970.
A. J. Ayer
Collections
Collections Ayer's biographer, Ben Rogers, deposited 7 boxes of research material accumulated through the writing process at University College London in 2007. The material was donated in collaboration with Ayer's family.
A. J. Ayer
Selected publications
Selected publications 1936, Language, Truth, and Logic, London: Gollancz., 2nd ed., with new introduction (1946) 1936, "Causation and free will",listed in some bibliographies as (The) "Freedom of the Will" (1936) The Aryan Path. 1940, The Foundations of Empirical Knowledge, London: Macmillan. 1954, Philosophical Essays, London: Macmillan. (Essays on freedom, phenomenalism, basic propositions, utilitarianism, other minds, the past, ontology.) 1957, "The conception of probability as a logical relation", in S. Korner, ed., Observation and Interpretation in the Philosophy of Physics, New York: Dover Publications. 1956, The Problem of Knowledge, London: Macmillan. 1957, "Logical Positivism - A Debate" (with F. C. Copleston) in: Edwards, Paul, Pap, Arthur (eds.), A Modern Introduction to Philosophy; readings from classical and contemporary sourcesreprinted in Ayer, A. J., (1990) The Meaning of Life and Other Essays, the same being reviewed (with attention given to the Ayer/Copleston debate) in: McGinn, Colin (30 August 1990). "Old Scores". London Review of Books. 12 (16). 1963, The Concept of a Person and Other Essays, London: Macmillan. (Essays on truth, privacy and private languages, laws of nature, the concept of a person, probability.) 1967, "Has Austin Refuted the Sense-Datum Theory?"listed (and reprinted) as "Has Austin Refuted Sense-data?" in Fann. K.T. (ed.), Symposium on J.L. Austin (1969) Synthese vol. XVIII, pp. 117–140. (Reprinted in Ayer 1969). 1968, The Origins of Pragmatism, London: Macmillan. 1969, Metaphysics and Common Sense, London: Macmillan. (Essays on knowledge, man as a subject for science, chance, philosophy and politics, existentialism, metaphysics, and a reply to Austin on sense-data theory [Ayer 1967].) 1971, Russell and Moore: The Analytical Heritage, London: Macmillan. 1972, Probability and Evidence, London: Macmillan. 1972, Russell, London: Fontana Modern Masters. 1973, The Central Questions of Philosophy, London: Weidenfeld. 1977, Part of My Life, London: Collins. 1979, "Replies", in G. F. Macdonald, ed., Perception and Identity: Essays Presented to A. J. Ayer, With His Replies, London: Macmillan; Ithaca, N.Y.: Cornell University Press.McDonald (1979) also includes a detailed listing of Ayer's philosophical works 1980, Hume, Oxford: Oxford University Press 1982, Philosophy in the Twentieth Century, London: Weidenfeld. 1984, Freedom and Morality and Other Essays, Oxford: Clarendon Press. 1984, More of My Life, London: Collins. 1986, Ludwig Wittgenstein, London: Penguin. 1986, Voltaire, New York: Random House. 1988, Thomas Paine, London: Secker & Warburg. 1990, The Meaning of Life and Other Essays, Weidenfeld & Nicolson.Reviewed in: McGinn, Colin (30 August 1990). "Old Scores". London Review of Books. 12 (16). 1991, "A Defense of Empiricism" in: Griffiths, A. Phillips (ed.), A. J. Ayer: Memorial Essays (Royal Institute of Philosophy Supplements). Cambridge University Press.Phillips (1991) also includes a 1989 interview with Ayer conducted by Ted Hondereich 1992, "Intellectual Autobiography" and Replies in: Lewis Edwin Hahn (ed.), The Philosophy of A.J. Ayer (The Library of Living Philosophers Volume XXI), Open Court Publishing Co.Hahn (1992) also includes a comprehensive 27-page bibliography of Ayer's writings compiled by Guida Crowley. *For more complete publication details see "The Philosophical Works of A. J. Ayer" (1979) and "Bibliography of the writings of A.J. Ayer" (1992).
A. J. Ayer
See also
See also A priori knowledge List of British philosophers
A. J. Ayer
References
References
A. J. Ayer
Footnotes
Footnotes
A. J. Ayer
Works cited
Works cited Ayer, A.J. (1989). "That undiscovered country", New Humanist, Vol. 104 (1), May, pp. 10–13. Rogers, Ben (1999). A.J. Ayer: A Life. New York: Grove Press. . (Chapter one and a review by Hilary Spurling, The New York Times, 24 December 2000.)
A. J. Ayer
Further reading
Further reading Jim Holt, "Positive Thinking" (review of Karl Sigmund, Exact Thinking in Demented Times: The Vienna Circle and the Epic Quest for the Foundations of Science, Basic Books, 449 pp.), The New York Review of Books, vol. LXIV, no. 20 (21 December 2017), pp. 74–76. Ted Honderich, Ayer's Philosophy and its Greatness. Anthony Quinton, Alfred Jules Ayer. Proceedings of the British Academy, 94 (1996), pp. 255–282. Graham Macdonald, Alfred Jules Ayer, Stanford Encyclopedia of Philosophy, 7 May 2005.
A. J. Ayer
External links
External links "Logical Positivism" (video) Men of Ideas interview with Bryan Magee (1978) "Frege, Russell, and Modern Logic" (video) The Great Philosophers interview with Bryan Magee (1987) Ayer's Elizabeth Rathbone Lecture on Philosophy & Politics Ayer entry in the Stanford Encyclopedia of Philosophy A.J. Ayer: Out of time by Alex Callinicos Appearance on Desert Island Discs – 3 August 1984 Ayer (Rogers) Papers at University College London Category:1910 births Category:1989 deaths Category:20th-century atheists Category:20th-century English non-fiction writers Category:Academics of University College London Category:Alumni of Christ Church, Oxford Category:Analytic philosophers Category:Aristotelian philosophers Category:Atheism in the United Kingdom Category:Atheist philosophers Category:Bard College faculty Category:British Army personnel of World War II Category:British people of Dutch-Jewish descent Category:British people of Swiss descent Category:British critics of religions Category:British Special Operations Executive personnel Category:Empiricists Category:English atheists Category:English humanists Category:English logicians Category:English people of Dutch-Jewish descent Category:English people of Swiss descent Category:20th-century English philosophers Category:British epistemologists Category:Fellows of Christ Church, Oxford Category:Fellows of the American Academy of Arts and Sciences Category:Fellows of the British Academy Category:Jewish atheists Category:Jewish humanists Category:Jewish philosophers Category:Knights Bachelor Category:Linguistic turn Category:Logical positivism Category:Logicians Category:Ontologists Category:People educated at Eton College Category:People from St John's Wood Category:British philosophers of culture Category:British philosophers of education Category:Philosophers of history Category:English philosophers of language Category:British philosophers of logic Category:British philosophers of mind Category:English philosophers of religion Category:English philosophers of science Category:Philosophers of technology Category:British philosophy writers Category:English political philosophers Category:Presidents of the Aristotelian Society Category:Presidents of Humanists UK Category:Vienna Circle Category:Welsh Guards officers Category:Wykeham Professors of Logic Category:English LGBTQ rights activists
A. J. Ayer
Table of Content
short description, Life, Philosophical ideas, Works, Awards, Collections, Selected publications, See also, References, Footnotes, Works cited, Further reading, External links
André Weil
Short description
André Weil (; ; 6 May 1906 – 6 August 1998) was a French mathematician, known for his foundational work in number theory and algebraic geometry. He was one of the most influential mathematicians of the twentieth century. His influence is due both to his original contributions to a remarkably broad spectrum of mathematical theories, and to the mark he left on mathematical practice and style, through some of his own works as well as through the Bourbaki group, of which he was one of the principal founders.
André Weil
Life
Life André Weil was born in Paris to agnostic Alsatian Jewish parents who fled the annexation of Alsace-Lorraine by the German Empire after the Franco-Prussian War in 1870–71. Simone Weil, who would later become a famous philosopher, was Weil's younger sister and only sibling. He studied in Paris, Rome and Göttingen and received his doctorate in 1928. While in Germany, Weil befriended Carl Ludwig Siegel. Starting in 1930, he spent two academic years at Aligarh Muslim University in India. Aside from mathematics, Weil held lifelong interests in classical Greek and Latin literature, Hinduism and Sanskrit literature: he had taught himself Sanskrit in 1920 at age 14.Amir D. Aczel,The Artist and the Mathematician, Basic Books, 2009 pp. 17ff., p. 25. After teaching for one year at Aix-Marseille University, he taught for six years at University of Strasbourg. He married Éveline de Possel (née Éveline Gillet) in 1937. Weil was in Finland when World War II broke out; he had been traveling in Scandinavia since April 1939. His wife Éveline returned to France without him. Weil was arrested in Finland at the outbreak of the Winter War on suspicion of spying; however, accounts of his life having been in danger were shown to be exaggerated.Osmo Pekonen: L'affaire Weil à Helsinki en 1939, Gazette des mathématiciens 52 (avril 1992), pp. 13–20. With an afterword by André Weil. Weil returned to France via Sweden and the United Kingdom, and was detained at Le Havre in January 1940. He was charged with failure to report for duty, and was imprisoned in Le Havre and then Rouen. It was in the military prison in Bonne-Nouvelle, a district of Rouen, from February to May, that Weil completed the work that made his reputation. He was tried on 3 May 1940. Sentenced to five years, he requested to be attached to a military unit instead, and was given the chance to join a regiment in Cherbourg. After the fall of France in June 1940, he met up with his family in Marseille, where he arrived by sea. He then went to Clermont-Ferrand, where he managed to join his wife, Éveline, who had been living in German-occupied France. In January 1941, Weil and his family sailed from Marseille to New York. He spent the remainder of the war in the United States, where he was supported by the Rockefeller Foundation and the Guggenheim Foundation. For two years, he taught undergraduate mathematics at Lehigh University, where he was unappreciated, overworked and poorly paid, although he did not have to worry about being drafted, unlike his American students. He quit the job at Lehigh and moved to Brazil, where he taught at the Universidade de São Paulo from 1945 to 1947, working with Oscar Zariski. Weil and his wife had two daughters, Sylvie (born in 1942) and Nicolette (born in 1946). He then returned to the United States and taught at the University of Chicago from 1947 to 1958, before moving to the Institute for Advanced Study, where he would spend the remainder of his career. He was a Plenary Speaker at the ICM in 1950 in Cambridge, Massachusetts,Weil, André. "Number theory and algebraic geometry." In Proc. Intern. Math. Congres., Cambridge, Mass., vol. 2, pp. 90–100. 1950. in 1954 in Amsterdam, and in 1978 in Helsinki. Weil was elected Foreign Member of the Royal Society in 1966. In 1979, he shared the second Wolf Prize in Mathematics with Jean Leray.
André Weil
Work
Work Weil made substantial contributions in a number of areas, the most important being his discovery of profound connections between algebraic geometry and number theory. This began in his doctoral work leading to the Mordell–Weil theorem (1928, and shortly applied in Siegel's theorem on integral points).A. Weil, L'arithmétique sur les courbes algébriques, Acta Math 52, (1929) p. 281–315, reprinted in vol 1 of his collected papers . Mordell's theorem had an ad hoc proof; Weil began the separation of the infinite descent argument into two types of structural approach, by means of height functions for sizing rational points, and by means of Galois cohomology, which would not be categorized as such for another two decades. Both aspects of Weil's work have steadily developed into substantial theories. Among his major accomplishments were the 1940s proof of the Riemann hypothesis for zeta-functions of curves over finite fields, Reprinted in Oeuvres Scientifiques/Collected Papers by André Weil and his subsequent laying of proper foundations for algebraic geometry to support that result (from 1942 to 1946, most intensively). The so-called Weil conjectures were hugely influential from around 1950; these statements were later proved by Bernard Dwork, Alexander Grothendieck, Michael Artin, and finally by Pierre Deligne, who completed the most difficult step in 1973. Weil introduced the adele ringA. Weil, Adeles and algebraic groups, Birkhauser, Boston, 1982 in the late 1930s, following Claude Chevalley's lead with the ideles, and gave a proof of the Riemann–Roch theorem with them (a version appeared in his Basic Number Theory in 1967). His 'matrix divisor' (vector bundle avant la lettre) Riemann–Roch theorem from 1938 was a very early anticipation of later ideas such as moduli spaces of bundles. The Weil conjecture on Tamagawa numbers proved resistant for many years. Eventually the adelic approach became basic in automorphic representation theory. He picked up another credited Weil conjecture, around 1967, which later under pressure from Serge Lang (resp. of Jean-Pierre Serre) became known as the Taniyama–Shimura conjecture (resp. Taniyama–Weil conjecture) based on a roughly formulated question of Taniyama at the 1955 Nikkō conference. His attitude towards conjectures was that one should not dignify a guess as a conjecture lightly, and in the Taniyama case, the evidence was only there after extensive computational work carried out from the late 1960s.Lang, S. "Some History of the Shimura-Taniyama Conjecture." Not. Amer. Math. Soc. 42, 1301–1307, 1995 Other significant results were on Pontryagin duality and differential geometry. He introduced the concept of a uniform space in general topology, as a by-product of his collaboration with Nicolas Bourbaki (of which he was a Founding Father). His work on sheaf theory hardly appears in his published papers, but correspondence with Henri Cartan in the late 1940s, and reprinted in his collected papers, proved most influential. He also chose the symbol ∅, derived from the letter Ø in the Norwegian alphabet (which he alone among the Bourbaki group was familiar with), to represent the empty set. Weil also made a well-known contribution in Riemannian geometry in his very first paper in 1926, when he showed that the classical isoperimetric inequality holds on non-positively curved surfaces. This established the 2-dimensional case of what later became known as the Cartan–Hadamard conjecture. He discovered that the so-called Weil representation, previously introduced in quantum mechanics by Irving Segal and David Shale, gave a contemporary framework for understanding the classical theory of quadratic forms. This was also a beginning of a substantial development by others, connecting representation theory and theta functions. Weil was a member of both the National Academy of Sciences and the American Philosophical Society.
André Weil
As expositor
As expositor Weil's ideas made an important contribution to the writings and seminars of Bourbaki, before and after World War II. He also wrote several books on the history of number theory.
André Weil
Beliefs
Beliefs Hindu thought had great influence on Weil.Borel, Armand. (see also) He was an agnostic, and he respected religions.
André Weil
Legacy
Legacy Asteroid 289085 Andreweil, discovered by astronomers at the Saint-Sulpice Observatory in 2004, was named in his memory. The official was published by the Minor Planet Center on 14 February 2014 ().
André Weil
Books
Books Mathematical works: Arithmétique et géométrie sur les variétés algébriques (1935) Sur les espaces à structure uniforme et sur la topologie générale (1937) L'intégration dans les groupes topologiques et ses applications (1940) Sur les courbes algébriques et les variétés qui s'en déduisent (1948) Variétés abéliennes et courbes algébriques (1948) Introduction à l'étude des variétés kählériennes (1958) Discontinuous subgroups of classical groups (1958) Chicago lecture notes Dirichlet Series and Automorphic Forms, Lezioni Fermiane (1971) Lecture Notes in Mathematics, vol. 189 Essais historiques sur la théorie des nombres (1975) Elliptic Functions According to Eisenstein and Kronecker (1976) Number Theory for Beginners (1979) with Maxwell Rosenlicht Adeles and Algebraic Groups (1982) Number Theory: An Approach Through History From Hammurapi to Legendre (1984) Collected papers: Œuvres Scientifiques, Collected Works, three volumes (1979) Autobiography: French: Souvenirs d'Apprentissage (1991) . Review in English by J. E. Cremona. English translation: The Apprenticeship of a Mathematician (1992), Review by Veeravalli S. Varadarajan; Review by Saunders Mac Lane Memoir by his daughter: At Home with André and Simone Weil by Sylvie Weil, translated by Benjamin Ivry; , Northwestern University Press, 2010.
André Weil
See also
See also List of things named after André Weil
André Weil
References
References
André Weil
External links
External links André Weil, by A. Borel, Bull. AMS 46 (2009), 661–666. André Weil: memorial articles in the Notices of the AMS by Armand Borel, Pierre Cartier, Komaravolu Chandrasekharan, Shiing-Shen Chern, and Shokichi Iyanaga Image of Weil A 1940 Letter of André Weil on Analogy in Mathematics Artless innocents and ivory-tower sophisticates: Some personalities on the Indian mathematical scene – M. S. Raghunathan La vie et l'oeuvre d'André Weil, by J-P. Serre, L'Ens. Math. 45 (1999),5–16. Correspondance entre Henri Cartan et André Weil (1928–1991), par Michèle Audin, Doc. Math. 6, Soc. Math. France, 2011. Category:1906 births Category:1998 deaths Category:20th-century French mathematicians Category:Jewish French scientists Category:French historians of mathematics Category:Jewish agnostics Category:French agnostics Category:French people of Jewish descent Category:Institute for Advanced Study faculty Category:Academic staff of Aligarh Muslim University Category:Arithmetic geometers Category:École Normale Supérieure alumni Category:Nicolas Bourbaki Category:Members of the French Academy of Sciences Category:Kyoto laureates in Basic Sciences Category:Wolf Prize in Mathematics laureates Category:Aligarh Muslim University alumni Category:Academic staff of the University of São Paulo Category:Foreign members of the Royal Society Category:Foreign associates of the National Academy of Sciences Category:Scientists from Paris Category:Lycée Saint-Louis alumni Category:20th-century French historians Category:Members of the American Philosophical Society Category:French expatriates in Brazil Category:French expatriates in the United States
André Weil
Table of Content
Short description, Life, Work, As expositor, Beliefs, Legacy, Books, See also, References, External links
Achaeans (Homer)
Short description
The Achaeans or Akhaians (; , "the Achaeans" or "of Achaea") is one of the names in Homer which is used to refer to the Greeks collectively. The term "Achaean" is believed to be related to the Hittite term Ahhiyawa and the Egyptian term Ekwesh which appear in texts from the Late Bronze Age and are believed to refer to the Mycenaean civilization or some part of it. In the historical period, the term fell into disuse as a general term for Greek people, and was generally reserved for inhabitants of the region of Achaea, a region in the north-central part of the Peloponnese. The city-states of this region later formed a confederation known as the Achaean League, which was influential during the 3rd and 2nd centuries BC.
Achaeans (Homer)
Etymology
Etymology According to Margalit FinkelbergMargalit Finkelberg, "From Ahhiyawa to Ἀχαιοί", Glotta 66 (1988): 127–134. the name Ἀχαιοί (earlier Ἀχαιϝοί) is possibly derived, via an intermediate form *Ἀχαϝyοί, from a hypothetical older GreekAccording to Finkelberg, this derivation does not necessitate an ultimate Greek and Indo-european origin of the word: "Obviously, this deduction cannot supply conclusive proof that Ahhiyawa presents a Greek word, the more so as neither the etymology of this word nor its cognates are known to us". form reflected in the Hittite form Aḫḫiyawā; the latter is attested in the Hittite archives, e.g. in the Tawagalawa letter. However, Robert S. P. Beekes doubted its validity and suggested a Pre-Greek *Akaywa-.R. S. P. Beekes, Etymological Dictionary of Greek, Brill, 2009, p. 181.
Achaeans (Homer)
Homeric versus later use
Homeric versus later use In Homer, the term Achaeans is one of the primary terms used to refer to the Greeks as a whole. It is used 598 times in the Iliad, often accompanied by the epithet "long-haired". Other common names used in Homer are Danaans (; Danaoi; used 138 times in the Iliad) and Argives (; ; used 182 times in the Iliad) while Panhellenes ( Panhellenes, "All of the Greeks") and Hellenes (;"Hellene" entry in Collins English Dictionary. Hellenes) both appear only once;See Iliad, II.2.530 for "Panhellenes" and Iliad II.2.653 for "Hellenes". All of the aforementioned terms were used synonymously to denote a common Greek identity. In some English translations of the Iliad, the Achaeans are simply called the Greeks throughout. Later, by the Archaic and Classical periods, the term "Achaeans" referred to inhabitants of the much smaller region of Achaea. Herodotus identified the Achaeans of the northern Peloponnese as descendants of the earlier, Homeric Achaeans. According to Pausanias, writing in the 2nd century AD, the term "Achaean" was originally given to those Greeks inhabiting the Argolis and Laconia.Pausanias. Description of Greece, VII.1. Pausanias and Herodotus both recount the legend that the Achaeans were forced from their homelands by the Dorians, during the legendary Dorian invasion of the Peloponnese. They then moved into the region later called Achaea. A scholarly consensus has not yet been reached on the origin of the historic Achaeans relative to the Homeric Achaeans and is still hotly debated. Former emphasis on presumed race, such as John A. Scott's article about the blond locks of the Achaeans as compared to the dark locks of "Mediterranean" Poseidon,. on the basis of hints in Homer, has been rejected by some. The contrasting belief that "Achaeans", as understood through Homer, is "a name without a country", an ethnos created in the Epic tradition,As William K. Prentice expressed this long-standing skepticism of a genuine Achaean ethnicity in the distant past, at the outset of his article "The Achaeans" (see ). has modern supporters among those who conclude that "Achaeans" were redefined in the 5th century BC, as contemporary speakers of Aeolic Greek. Karl Beloch suggested there was no Dorian invasion, but rather that the Peloponnesian Dorians were the Achaeans.. Eduard Meyer, disagreeing with Beloch, instead put forth the suggestion that the real-life Achaeans were mainland pre-Dorian Greeks.. His conclusion is based on his research on the similarity between the languages of the Achaeans and pre-historic Arcadians. William Prentice disagreed with both, noting archeological evidence suggests the Achaeans instead migrated from "southern Asia Minor to Greece, probably settling first in lower Thessaly" probably prior to 2000 BC..
Achaeans (Homer)
Hittite documents
Hittite documents thumb|175px|left|Map showing the Hittite Empire, Ahhiyawa (Achaeans) and Wilusa (Troy) in . Some Hittite texts mention a nation to the west called Ahhiyawa ( Aḫḫiyawa).; ; . In the earliest reference to this land, a letter outlining the treaty violations of the Hittite vassal Madduwatta,Translation of the Sins of Madduwatta it is called Ahhiya. Another important example is the Tawagalawa Letter written by an unnamed Hittite king (most probably Hattusili III) of the empire period (14th–13th century BC) to the king of Ahhiyawa, treating him as an equal and implying Miletus (Millawanda) was under his control.Translation of the Tawagalawa Letter It also refers to an earlier "Wilusa episode" involving hostility on the part of Ahhiyawa. Ahhiya(wa) has been identified with the Achaeans of the Trojan War and the city of Wilusa with the legendary city of Troy (note the similarity with early Greek Wilion, later Ilion, the name of the acropolis of Troy). Emil Forrer, a Swiss Hittitologist who worked on the Boghazköy tablets in Berlin, said the Achaeans of pre-Homeric Greece were directly associated with the term "Land of Ahhiyawa" mentioned in the Hittite texts.. His conclusions at the time were challenged by other Hittitologists (i.e. Johannes Friedrich in 1927 and Albrecht Götze in 1930), as well as by Ferdinand Sommer, who published his (The Ahhiyawa Documents) in 1932. The exact relationship of the term Ahhiyawa to the Achaeans beyond a similarity in pronunciation was hotly debated by scholars, even following the discovery that Mycenaean Linear B is an early form of Greek; the earlier debate was summed up in 1984 by Hans G. Güterbock of the Oriental Institute.. More recent research based on new readings and interpretations of the Hittite texts, as well as of the material evidence for Mycenaean contacts with the Anatolian mainland, came to the conclusion that Ahhiyawa referred to the Mycenaean world, or at least to a part of it.; . Scholarship up to 2011 was reviewed by Gary M. Beckman et al. In this review, the increasing acceptance of the Ahhiyawa-Mycenaeans hypothesis was noted. As to the exact location of Ahhiyawa:The Ahhiyawa Texts. Editors: Gary M. Beckman, Trevor Bryce, Eric H. Cline; Society of Biblical Literature, 2011; ISBN 158983268X In fact, the authors state that "there is now little doubt that Ahhiyawa was a reference by the Hittites to some or all of the Bronze Age Mycenaean world", and that Forrer was "largely correct after all".
Achaeans (Homer)
Egyptian sources
Egyptian sources thumb|175px|right|Map of Mycenaean cultural areas, 1400–1100 BC (unearthed sites in red dots). It has been proposed that Ekwesh of the Egyptian records may relate to Achaea (compared to Hittite Ahhiyawa), whereas Denyen and Tanaju may relate to Classical Greek Danaoi.. The earliest textual reference to the Mycenaean world is in the Annals of Thutmosis III (–1425 BC), which refers to messengers from the king of the Tanaju, , offering greeting gifts to the Egyptian king, in order to initiate diplomatic relations, when the latter campaigned in Syria. Tanaju is also listed in an inscription at the Mortuary Temple of Amenhotep III. The latter ruled Egypt in –1344 BC. Moreover, a list of the cities and regions of the Tanaju is also mentioned in this inscription; among the cities listed are Mycenae, Nauplion, Kythera, Messenia and the Thebaid (region of Thebes). During the 5th year of Pharaoh Merneptah, a confederation of Libyan and northern peoples is supposed to have attacked the western delta. Included amongst the ethnic names of the repulsed invaders is the Ekwesh or Eqwesh, whom some have seen as Achaeans, although Egyptian texts specifically mention these Ekwesh to be circumcised. Homer mentions an Achaean attack upon the delta, and Menelaus speaks of the same in Book IV of the Odyssey to Telemachus when he recounts his own return home from the Trojan War. Some ancient Greek authors also say that Helen had spent the time of the Trojan War in Egypt, and not at Troy, and that after Troy the Greeks went there to recover her.For example, in Euripides, Stesichorus, and Herodotus; HELEN wsu.edu
Achaeans (Homer)
Greek mythology
Greek mythology In Greek mythology, the perceived cultural divisions among the Hellenes were represented as legendary lines of descent that identified kinship groups, with each line being derived from an eponymous ancestor. Each of the Greek ethne were said to be named in honor of their respective ancestors: Achaeus of the Achaeans, Danaus of the Danaans, Cadmus of the Cadmeans (the Thebans), Hellen of the Hellenes (not to be confused with Helen of Troy), Aeolus of the Aeolians, Ion of the Ionians, and Dorus of the Dorians. Cadmus from Phoenicia, Danaus from Egypt, and Pelops from Anatolia each gained a foothold in mainland Greece and were assimilated and Hellenized. Hellen, Graikos, Magnes, and Macedon were sons of Deucalion and Pyrrha, the only people who survived the Great Flood;Hesiod. Catalogue of Women, Fragments. the ethne were said to have originally been named Graikoi after the elder son but later renamed Hellenes after Hellen who was proved to be the strongest.Aristotle. Meteorologica, I.14. Sons of Hellen and the nymph Orseis were Dorus, Xuthos, and Aeolus.Pseudo-Apollodorus. Bibliotheca, I.7.3. Sons of Xuthos and Kreousa, daughter of Erechthea, were Ion and Achaeus. According to Hyginus, 22 Achaeans killed 362 Trojans during their ten years at Troy.Hyginus. Fabulae, 114.In particular: Achilles 72, Antilochus 2, Protesilaus 4, Peneleos 2, Eurypylus 1, Ajax 14, Thoas 2, Leitus 20, Thrasymedes 2, Agamemnon 16, Diomedes 18, Menelaus 8, Philoctetes 3, Meriones 7, Odysseus 12, Idomeneus 13, Leonteus 5, Ajax 28, Patroclus 54, Polypoetes 1, Teucer 30, Neoptolemus 6; a total of 362 Trojans.