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Topic Review
Soufrière Hills Volcano
User:RMCD bot/subject notice The Soufrière Hills volcano is an active, complex stratovolcano with many lava domes forming its summit on the Caribbean island of Montserrat. Many volcanoes in the Caribbean are named Soufrière (French: "sulfur outlet"). These include La Soufrière or Soufrière Saint Vincent on the island of Saint Vincent, and La Grande Soufrière on Guadeloupe. After a long period of dormancy, the Soufrière Hills volcano became active in 1995 and has continued to erupt ever since. Its eruptions have rendered more than half of Montserrat uninhabitable, destroying the capital city, Plymouth, and causing widespread evacuations: about two thirds of the population have left the island. It is andesitic in nature, and the current pattern of activity includes periods of lava dome growth, punctuated by brief episodes of dome collapse which result in pyroclastic flows, ash venting, and explosive eruption. The volcano is monitored by the Montserrat Volcano Observatory. Volcanic gas emissions from this volcano are measured by a Multi-Component Gas Analyzer System, which detects pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.
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Topic Review
Silicate Minerals
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of the Earth's crust. In mineralogy, silica (silicon dioxide) SiO2 is usually considered a silicate mineral. Silica is found in nature as the mineral quartz, and its polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this geologic cycle. For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seawater. The frustules of dead diatoms are a major constituent of deep ocean sediment, and of diatomaceous earth.
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  • 25 Oct 2022
Topic Review
Counterculture of the 1960s
The counterculture of the 1960s refers to an anti-establishment cultural phenomenon that developed first in the United Kingdom (UK) and the United States (US) and then spread throughout much of the Western world between the mid-1960s and the mid-1970s, with London, New York City, and San Francisco being hotbeds of early countercultural activity. The aggregate movement gained momentum as the Civil Rights Movement continued to grow, and would later become revolutionary with the expansion of the U.S. government's extensive military intervention in Vietnam. As the 1960s progressed, widespread social tensions also developed concerning other issues, and tended to flow along generational lines regarding human sexuality, women's rights, traditional modes of authority, experimentation with psychoactive drugs, and differing interpretations of the American Dream. Many key movements related to these issues were born or advanced within the counterculture of the 1960s. As the era unfolded, new cultural forms and a dynamic subculture which celebrated experimentation, modern incarnations of Bohemianism, and the rise of the hippie and other alternative lifestyles, emerged. This embracing of creativity is particularly notable in the works of British Invasion bands such as The Beatles, and filmmakers whose works became far less restricted by censorship. In addition to the trendsetting Beatles, many other creative artists, authors, and thinkers, within and across many disciplines, helped define the counterculture movement. Several factors distinguished the counterculture of the 1960s from the anti-authoritarian movements of previous eras. The post-World War II "baby boom" generated an unprecedented number of potentially disaffected young people as prospective participants in a rethinking of the direction of American and other democratic societies. Post-war affluence allowed many of the counterculture generation to move beyond a focus on the provision of the material necessities of life that had preoccupied their Depression-era parents. The era was also notable in that a significant portion of the array of behaviors and "causes" within the larger movement were quickly assimilated within mainstream society, particularly in the US, even though counterculture participants numbered in the clear minority within their respective national populations. The counterculture era essentially commenced in earnest with the assassination of John F. Kennedy in November 1963. It became absorbed into the popular culture with the termination of US combat military involvement in Southeast Asia and the end of the draft in 1973, and ultimately with the resignation of President Richard Nixon in August 1974.
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Topic Review
Wolf Distribution
Wolf distribution is the species distribution of the wolf (Canis lupus). Originally, wolves occurred in Eurasia above the 12th parallel north and in North America above the 15th parallel north. However, deliberate human persecution has reduced the species' range to about one-third, because of livestock predation and fear of wolf attacks on humans. The species is now extirpated (made locally extinct) in much of Western Europe, Mexico, and the contiguous United States , and completely from the British Isles and the Japanese archipelago. In modern history, the gray wolf occurs mostly in wilderness and remote areas, particularly in Canada , Alaska, the Northern United States, Europe and Asia from about the 75th parallel north to the 12th parallel north. Wolf population declines have been arrested since the 1970s, and have fostered recolonization and reintroduction in parts of its former range, due to legal protection, changes in land-use and rural human population shifts to cities. Competition with humans for livestock and game species, concerns over the danger posed by wolves to people, and habitat fragmentation pose a continued threat to the species. Despite these threats, because of the gray wolf's relatively widespread range and stable population, it is classified as Least Concern on the IUCN Red List. In Africa the population of wolves is limited to the northern regions with the African golden wolf (Canis lupaster) north of the Sahara and the Ethiopian wolf (Canis simensis) in Ethiopia.
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Topic Review
Mobilization of Arsenic
One of the most significant elements in the environment is arsenic (As). It is a hazardous metalloid that causes contamination of soil and water supplies as a result of numerous anthropogenic and natural sources.
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Topic Review
Earth Strike
Earth Strike is an international grassroots movement that called for a global general strike for climate action. Their aim was a global general strike lasting from 20 until 27 September 2019. The movement has had public support from organizations including Extinction Rebellion and Fridays for Future, as well as public figures including Noam Chomsky. The Earth Strikes were part of the worldwide September 2019 climate strikes, which gathered millions of protesters. An estimated 6 million people participated in strikes worldwide from 20–27 September. Youth environmental activist Greta Thunberg spoke in New York on the 20 September strike and Montreal on the 27 September strike.
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Topic Review
Bio-energy with Carbon Capture and Storage
Bio-energy with carbon capture and storage (BECCS) is a potential greenhouse gas mitigation technology which produces negative carbon dioxide emissions by combining bioenergy (energy from biomass) use with geologic carbon capture and storage. The concept of BECCS is drawn from the integration of trees and crops, which extract carbon dioxide (CO2) from the atmosphere as they grow, the use of this biomass in processing industries or power plants, and the application of carbon capture and storage via CO2 injection into geological formations. There are other non-BECCS forms of carbon dioxide removal and storage that include technologies such as biochar, carbon dioxide air capture and biomass burial and enhanced weathering. According to a recent Biorecro report, there is 550 000 tonnes CO2/year in total BECCS capacity currently operating, divided between three different facilities (as of January 2012). In the IPCC Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), BECCS was indicated as a key technology for reaching low carbon dioxide atmospheric concentration targets. The negative emissions that can be produced by BECCS has been estimated by the Royal Society to be equivalent to a 50 to 150 ppm decrease in global atmospheric carbon dioxide concentrations and according to the International Energy Agency, the BLUE map climate change mitigation scenario calls for more than 2 gigatonnes of negative CO2 emissions per year with BECCS in 2050. According to Stanford University, 10 gigatonnes is achievable by this date. The Imperial College London, the UK Met Office Hadley Centre for Climate Prediction and Research, the Tyndall Centre for Climate Change Research, the Walker Institute for Climate System Research, and the Grantham Institute for Climate Change issued a joint report on carbon dioxide removal technologies as part of the AVOID: Avoiding dangerous climate change research program, stating that "Overall, of the technologies studied in this report, BECCS has the greatest maturity and there are no major practical barriers to its introduction into today’s energy system. The presence of a primary product will support early deployment." According to the OECD, "Achieving lower concentration targets (450 ppm) depends significantly on the use of BECCS".
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Topic Review
Geography of Middle-Earth
The geography of Middle-earth encompasses the physical, political, and moral geography of J. R. R. Tolkien's fictional world of Middle-earth, strictly a continent on the planet of Arda but widely taken to mean the physical world, and Eä, all of creation, as well as all of his writings about it. Arda was created as a flat world, incorporating a Western continent, Aman, which became the home of the godlike Valar, as well as Middle-earth. At the end of the First Age, the Western part of Middle-earth, Beleriand, was drowned in the War of Wrath. In the Second Age, a large island, Númenor, was created in the Great Sea, Belegaer, between Aman and Middle-earth; it was destroyed in a cataclysm at the end of the Second Age, in which Arda was remade as a spherical world, and Aman was removed so that Men could not reach it. In The Lord of the Rings, Middle-earth at the end of the Third Age is described as having free peoples, namely Men, Hobbits, Elves, and Dwarves in the West, opposed to peoples under the control of the Dark Lord Sauron in the East. Some commentators have seen this as implying a moral geography of Middle-earth.
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Topic Review
True Range Multilateration
True range multilateration is a method to determine the location of a movable vehicle or stationary point in space using multiple ranges (distances) between the vehicle/point and multiple spatially-separated known locations (often termed 'stations'). True range multilateration is both a mathematical topic and an applied technique used in several fields. A practical application involving a fixed location is the trilateration method of surveying. Applications involving vehicle location are termed navigation when on-board persons/equipment are informed of its location, and are termed surveillance when off-vehicle entities are informed of the vehicle's location. Two slant-ranges from two known locations can be used to locate a third point in a two-dimensional Cartesian space (plane), which is a frequently applied technique (e.g., in surveying). Similarly, two spherical ranges can be used to locate a point on a sphere, which is a fundamental concept of the ancient discipline of celestial navigation — termed the altitude intercept problem. Moreover, if more than the minimum number of ranges are available, it is good practice to utilize those as well. This article addresses the general issue of position determination using multiple ranges. In two-dimensional geometry, it is known that if a point lies on two circles, then the circle centers and the two radii provide sufficient information to narrow the possible locations down to two – one of which is the desired solution and the other is an ambiguous solution. Additional information often narrow the possibilities down to a unique location. In three-dimensional geometry, when it is known that a point lies on the surfaces of three spheres, then the centers of the three spheres along with their radii also provide sufficient information to narrow the possible locations down to no more than two (unless the centers lie on a straight line). True range multilateration can be contrasted to the more frequently encountered (pseudorange) multilateration, which employs range differences to locate a (typically, movable) point. Pseudo range multilateration is almost always implemented by measuring times-of-arrival (TOAs) of energy waves. True range multilateration can also be contrasted to triangulation, which involves the measurement of angles. Multiple, sometimes overlapping and conflicting terms are employed for similar concepts – e.g., multilateration without modification has been used for aviation systems employing both true ranges and pseudo ranges. Moreover, different fields of endeavor may employ different terms. In geometry, trilateration is defined as the process of determining absolute or relative locations of points by measurement of distances, using the geometry of circles, spheres or triangles. In surveying, trilateration is a specific technique. The term true range multilateration is accurate, general and unambiguous. Authors have also used the terms range-range and rho-rho multilateration for this concept.
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Topic Review
Bryce Canyon National Park
Bryce Canyon National Park (/braɪs/) is an American national park located in southwestern Utah. The major feature of the park is Bryce Canyon, which despite its name, is not a canyon, but a collection of giant natural amphitheaters along the eastern side of the Paunsaugunt Plateau. Bryce is distinctive due to geological structures called hoodoos, formed by frost weathering and stream erosion of the river and lake bed sedimentary rocks. The red, orange, and white colors of the rocks provide spectacular views for park visitors. Bryce Canyon National Park is much smaller, and sits at a much higher elevation than nearby Zion National Park. The rim at Bryce varies from 8,000 to 9,000 feet (2,400 to 2,700 m). The Bryce Canyon area was settled by Mormon pioneers in the 1850s and was named after Ebenezer Bryce, who homesteaded in the area in 1874. The area around Bryce Canyon was originally designated as a national monument by President Warren G. Harding in 1923 and was redesignated as a national park by Congress in 1928. The park covers 35,835 acres (55.992 sq mi; 14,502 ha; 145.02 km2) and receives substantially fewer visitors than Zion National Park (nearly 4.3 million in 2016) or Grand Canyon National Park (nearly 6 million in 2016), largely due to Bryce's more remote location. In 2016, Bryce Canyon received 2,365,110 recreational visitors, representing an increase of 35% from the prior year.
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