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Violent incidents
27 June 1976: Air France Flight 139, originating in Tel Aviv, Israel and carrying 248 passengers and a crew of 12 took off from Athens, Greece, headed for Paris, France. The flight was hijacked by terrorists, and was eventually flown to Entebbe Airport in Uganda. At the airport, Israeli commandos r... | Airbus A300 | Wikipedia | 464 | 2524 | https://en.wikipedia.org/wiki/Airbus%20A300 | Technology | Specific aircraft_2 | null |
22 November 2003: European Air Transport OO-DLL, operating on behalf of DHL Aviation, was hit by an SA-14 'Gremlin' missile after takeoff from Baghdad International Airport. The aeroplane lost hydraulic pressure and thus the controls. After extending the landing gear to create more drag, the crew piloted the plane usin... | Airbus A300 | Wikipedia | 162 | 2524 | https://en.wikipedia.org/wiki/Airbus%20A300 | Technology | Specific aircraft_2 | null |
Aircraft on display
Fifteen A300s are currently preserved:
F-BUAD Airbus A300 ZERO-G, since August 2015 preserved at Cologne Bonn Airport, Germany.
F-WUAB The first prototype of the Airbus A300 is Partially preserved with a fuselage section, the right-hand wing, and an engine on display at the Deutsches Museum
ex-HL7... | Airbus A300 | Wikipedia | 434 | 2524 | https://en.wikipedia.org/wiki/Airbus%20A300 | Technology | Specific aircraft_2 | null |
Agent Orange is a chemical herbicide and defoliant, one of the tactical use Rainbow Herbicides. It was used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. The U.S. was strongly influenced by the British who used Agent Orange during the Mal... | Agent Orange | Wikipedia | 489 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
The use of Agent Orange in Vietnam resulted in numerous legal actions. The United Nations ratified United Nations General Assembly Resolution 31/72 and the Environmental Modification Convention. Lawsuits filed on behalf of both U.S. and Vietnamese veterans sought compensation for damages.
Agent Orange was first used b... | Agent Orange | Wikipedia | 413 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Development
Several herbicides were developed as part of efforts by the United States and the United Kingdom to create herbicidal weapons for use during World War II. These included 2,4-D, 2,4,5-T, MCPA (2-methyl-4-chlorophenoxyacetic acid, 1414B and 1414A, recoded LN-8 and LN-32), and isopropyl phenylcarbamate (1313, ... | Agent Orange | Wikipedia | 377 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In the years after the war, the U.S. tested 1,100 compounds, and field trials of the more promising ones were done at British stations in India and Australia, in order to establish their effects in tropical conditions, as well as at the U.S. testing ground in Florida. Between 1950 and 1952, trials were conducted in Tan... | Agent Orange | Wikipedia | 511 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
During the Vietnam War, between 1962 and 1971, the United States military sprayed nearly of various chemicals – the "rainbow herbicides" and defoliants – in Vietnam, eastern Laos, and parts of Cambodia as part of Operation Ranch Hand, reaching its peak from 1967 to 1969. For comparison purposes, an olympic size pool h... | Agent Orange | Wikipedia | 449 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
The U.S. military began targeting food crops in October 1962, primarily using Agent Blue; the American public was not made aware of the crop destruction programs until 1965 (and it was then believed that crop spraying had begun that spring). In 1965, 42% of all herbicide spraying was dedicated to food crops. In 1965, m... | Agent Orange | Wikipedia | 284 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Many experts at the time, including plant physiologist and bioethicist Arthur Galston, opposed herbicidal warfare because of concerns about the side effects to humans and the environment by indiscriminately spraying the chemical over a wide area. As early as 1966, resolutions were introduced to the United Nations charg... | Agent Orange | Wikipedia | 479 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Health effects
There are various types of cancer associated with Agent Orange, including chronic B-cell leukemia, Hodgkin's lymphoma, multiple myeloma, non-Hodgkin's lymphoma, prostate cancer, respiratory cancer, lung cancer, and soft tissue sarcomas. However, these associations are spurious, and a review of the litera... | Agent Orange | Wikipedia | 485 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Twenty-eight of the former U.S. military bases in Vietnam where the herbicides were stored and loaded onto airplanes may still have high levels of dioxins in the soil, posing a health threat to the surrounding communities. Extensive testing for dioxin contamination has been conducted at the former U.S. airbases in Da N... | Agent Orange | Wikipedia | 449 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In a November 2004 Zogby International poll of 987 people, 79% of respondents thought the U.S. chemical companies which produced Agent Orange defoliant should compensate U.S. soldiers who were affected by the toxic chemical used during the war in Vietnam and 51% said they supported compensation for Vietnamese Agent Ora... | Agent Orange | Wikipedia | 400 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In 2006 progress was made in the form of a Memorandum of Understanding signed between the New Zealand government, representatives of New Zealand Vietnam veterans, and the Royal New Zealand Returned and Services' Association (RSA) for monetary compensation for New Zealand Vietnam veterans who have conditions as evidence... | Agent Orange | Wikipedia | 472 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
U.S. Public Health Service
Publications by the United States Public Health Service have shown that Vietnam veterans, overall, have increased rates of cancer, and nerve, digestive, skin, and respiratory disorders. The Centers for Disease Control and Prevention notes that in particular, there are higher rates of acute/ch... | Agent Orange | Wikipedia | 451 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
One noteworthy exception, according to the U.S. Department of Labor, is a claim filed with the CIA by an employee of "a self-insured contractor to the CIA that was no longer in business." The CIA advised the Department of Labor that it "had no objections" to paying the claim and Labor accepted the claim for payment:
E... | Agent Orange | Wikipedia | 434 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
International
The extensive environmental damage that resulted from usage of the herbicide prompted the United Nations to pass Resolution 31/72 and ratify the Environmental Modification Convention. Many states do not regard this as a complete ban on the use of herbicides and defoliants in warfare, but it does require c... | Agent Orange | Wikipedia | 425 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In 1980, Mayerson, with Sgt. Charles E. Hartz as their principal client, filed the first U.S. Agent Orange class-action lawsuit in Pennsylvania, for the injuries military personnel in Vietnam suffered through exposure to toxic dioxins in the defoliant. Attorney Mayerson co-wrote the brief that certified the Agent Orang... | Agent Orange | Wikipedia | 247 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
The chemical companies involved denied that there was a link between Agent Orange and the veterans' medical problems. However, on May 7, 1984, seven chemical companies settled the class-action suit out of court just hours before jury selection was to begin. The companies agreed to pay $180 million as compensation if th... | Agent Orange | Wikipedia | 460 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
New Jersey Agent Orange Commission
In 1980, New Jersey created the New Jersey Agent Orange Commission, the first state commission created to study its effects. The commission's research project in association with Rutgers University was called "The Pointman Project". It was disbanded by Governor Christine Todd Whitman ... | Agent Orange | Wikipedia | 190 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
U.S. Congress
In 1991, Congress enacted the Agent Orange Act, giving the Department of Veterans Affairs the authority to declare certain conditions "presumptive" to exposure to Agent Orange/dioxin, making these veterans who served in Vietnam eligible to receive treatment and compensation for these conditions. The same ... | Agent Orange | Wikipedia | 510 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
U.S.–Vietnamese government negotiations
In 2002, Vietnam and the U.S. held a joint conference on Human Health and Environmental Impacts of Agent Orange. Following the conference, the U.S. National Institute of Environmental Health Sciences (NIEHS) began scientific exchanges between the U.S. and Vietnam, and began discu... | Agent Orange | Wikipedia | 473 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Secretary of State Hillary Clinton stated during a visit to Hanoi in October 2010 that the U.S. government would begin work on the clean-up of dioxin contamination at the Da Nang Airbase. In June 2011, a ceremony was held at Da Nang airport to mark the start of U.S.-funded decontamination of dioxin hotspots in Vietnam.... | Agent Orange | Wikipedia | 466 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Author and activist George Jackson had written previously that:If the Americans were guilty of war crimes for using Agent Orange in Vietnam, then the British would be also guilty of war crimes as well since they were the first nation to deploy the use of herbicides and defoliants in warfare and used them on a large sca... | Agent Orange | Wikipedia | 454 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
The center provides medical care, rehabilitation and vocational training for children and veterans from Vietnam who have been affected by Agent Orange. In 1998, The Vietnam Red Cross established the Vietnam Agent Orange Victims Fund to provide direct assistance to families throughout Vietnam that have been affected. In... | Agent Orange | Wikipedia | 446 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
On June 16, 2010, members of the U.S.-Vietnam Dialogue Group on Agent Orange/Dioxin unveiled a comprehensive 10-year Declaration and Plan of Action to address the toxic legacy of Agent Orange and other herbicides in Vietnam. The Plan of Action was released as an Aspen Institute publication and calls upon the U.S. and V... | Agent Orange | Wikipedia | 339 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Canada
The U.S. military, with the permission of the Canadian government, tested herbicides, including Agent Orange, in the forests near Canadian Forces Base Gagetown in New Brunswick. In 2007, the government of Canada offered a one-time ex gratia payment of $20,000 as compensation for Agent Orange exposure at CFB Gage... | Agent Orange | Wikipedia | 481 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
South Korea
Agent Orange was used in South Korea in the late 1960s and in 1999, about 20,000 South Koreans filed two separated lawsuits against U.S. companies, seeking more than $5 billion in damages. After losing a decision in 2002, they filed an appeal. In January 2006, the South Korean Appeals Court ordered Dow Chem... | Agent Orange | Wikipedia | 332 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
The use of Agent Orange has been controversial in New Zealand, because of the exposure of New Zealand troops in Vietnam and because of the production of herbicide used in Agent Orange which has been alleged at various times to have been exported for use in the Vietnam War and to other users by the Ivon Watkins-Dow chem... | Agent Orange | Wikipedia | 467 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
From July to September 1977 during Operation Pacer HO, the entire stock of Agent Orange from both Herbicide Orange storage sites at Gulfport and Johnston Atoll was subsequently incinerated in four separate burns in the vicinity of Johnston Island aboard the Dutch-owned waste incineration ship .
As of 2004, some records... | Agent Orange | Wikipedia | 467 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Thailand
Agent Orange was tested by the United States in Thailand during the Vietnam War. In 1999, buried drums were uncovered and confirmed to be Agent Orange. Workers who uncovered the drums fell ill while upgrading the airport near Hua Hin District, 100 km south of Bangkok. Vietnam-era veterans whose service involve... | Agent Orange | Wikipedia | 443 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In 1978, the EPA suspended spraying of Agent Orange in national forests.
Agent Orange was sprayed on thousands of acres of brush in the Tennessee Valley for 15 years before scientists discovered the herbicide was dangerous. Monroe County, Tennessee, is one of the locations known to have been sprayed according to the Te... | Agent Orange | Wikipedia | 509 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
In 2016, the EPA laid out its plan for cleaning up an stretch of the Passaic River in New Jersey, with an estimated cost of $1.4 billion. The contaminants reached to Newark Bay and other waterways, according to the EPA, which has designated the area a Superfund site. Since destruction of the dioxin requires high tempe... | Agent Orange | Wikipedia | 83 | 2547 | https://en.wikipedia.org/wiki/Agent%20Orange | Technology | Pest and disease control | null |
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0; the years before that are designated with negative numbers and the years after that are designated with positive numbers. Astronomers use the Julian calendar for years before ... | Astronomical year numbering | Wikipedia | 349 | 2551 | https://en.wikipedia.org/wiki/Astronomical%20year%20numbering | Technology | Timekeeping | null |
In his Rudolphine Tables (1627), Johannes Kepler used a prototype of year zero which he labeled Christi (Christ's) between years labeled Ante Christum (Before Christ) and Post Christum (After Christ) on the mean motion tables for the Sun, Moon, Saturn, Jupiter, Mars, Venus and Mercury. In 1702, the French astronomer Ph... | Astronomical year numbering | Wikipedia | 480 | 2551 | https://en.wikipedia.org/wiki/Astronomical%20year%20numbering | Technology | Timekeeping | null |
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate... | Ant | Wikipedia | 467 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Etymology
The word ant and the archaic word emmet are derived from , of Middle English, which come from of Old English; these are all related to Low Saxon , and varieties (Old Saxon ) and to German (Old High German ). All of these words come from West Germanic *, and the original meaning of the word was "the biter"... | Ant | Wikipedia | 397 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant (Sphecomyrma) that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has features found in some wasps, but not found in modern ants. The oldest fossils of ants date to the mid-Cretac... | Ant | Wikipedia | 489 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ants have a cosmopolitan distribution. They are found on all continents except Antarctica, and only a few large islands, such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species. Ants occupy a wide range of ecological niches and exploit many different food resources as direct or i... | Ant | Wikipedia | 454 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ants are distinct in their morphology from other insects in having geniculate (elbowed) antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma, and metasoma are the three distinct body segments (formally tagmata). The petiole forms a narrow... | Ant | Wikipedia | 407 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ant eyes are good for acute movement detection, but do not offer a high resolution image. They also have three small ocelli (simple eyes) on the top of the head that detect light leve... | Ant | Wikipedia | 443 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor (micrergates), median, and major ergates (macrergates). Often, the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. Although formally known as dinergates, such individu... | Ant | Wikipedia | 496 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Genome size
Genome size is a fundamental characteristic of an organism. Ants have been found to have tiny genomes, with the evolution of genome size suggested to occur through loss and accumulation of non-coding regions, mainly transposable elements, and occasionally by whole genome duplication. This may be related to ... | Ant | Wikipedia | 407 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
A new ergate spends the first few days of its adult life caring for the queen and young. She then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. Such age-based task-specialization or polyethis... | Ant | Wikipedia | 458 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Drones can also mate with existing queens by entering a foreign colony, such as in army ants. When the drone is initially attacked by the workers, it releases a mating pheromone. If recognized as a mate, it will be carried to the queen to mate. Males may also patrol the nest and fight others by grabbing them with their... | Ant | Wikipedia | 402 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Mated females then seek a suitable place to begin a colony. There, they break off their wings using their tibial spurs and begin to lay and care for eggs. The females can selectively fertilise future eggs with the sperm stored to produce diploid workers or lay unfertilized haploid eggs to produce drones. The first work... | Ant | Wikipedia | 395 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ants communicate with each other using pheromones, sounds, and touch. Since most ants live on the ground, they use the soil surface to leave pheromone trails that may be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followe... | Ant | Wikipedia | 495 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
The sting of jack jumper ants can be lethal for humans, and an antivenom has been developed for it. Fire ants, Solenopsis spp., are unique in having a venom sac containing piperidine alkaloids. Their stings are painful and can be dangerous to hypersensitive people. Formicine ants secrete a poison from their glands, mad... | Ant | Wikipedia | 414 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
In addition to defence against predators, ants need to protect their colonies from pathogens. Secretions from the metapleural gland, unique to the ants, produce a complex range of chemicals including several with antibiotic properties. Some worker ants maintain the hygiene of the colony and their activities include und... | Ant | Wikipedia | 424 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made... | Ant | Wikipedia | 481 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Most ants are generalist predators, scavengers, and indirect herbivores, but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes to upgrade the nutritional value of the food they collect ... | Ant | Wikipedia | 252 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Foraging ants travel distances of up to from their nest and scent trails allow them to find their way back even in the dark. In hot and arid regions, day-foraging ants face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants of the genus Cataglyphis s... | Ant | Wikipedia | 511 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Cooperation and competition
Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes ins... | Ant | Wikipedia | 489 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They also are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae, and eggs, consuming the food s... | Ant | Wikipedia | 312 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Myrmecophilous (ant-loving) caterpillars of the butterfly family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. The chemicals in t... | Ant | Wikipedia | 456 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more nesting sites inside the stems of the Duroia trees. Although some ants obtain nectar from flowers, pollination by ant... | Ant | Wikipedia | 412 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Many plant species have seeds that are adapted for dispersal by ants. Seed dispersal by ants or myrmecochory is widespread, and new estimates suggest that nearly 9% of all plant species may have such ant associations. Often, seed-dispersing ants perform directed dispersal, depositing the seeds in locations that increas... | Ant | Wikipedia | 459 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants react to their infection by climbing up plants and sinking their mandibles into plant tissue. The fungus kills the ants, grows on their remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse it... | Ant | Wikipedia | 337 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Army ants forage in a wide roving column, attacking any animals in that path that are unable to escape. In Central and South America, Eciton burchellii is the swarming ant most commonly attended by "ant-following" birds such as antbirds and woodcreepers. This behaviour was once considered mutualistic, but later studies... | Ant | Wikipedia | 476 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Some ants have toxic venom and are of medical importance. The species include Paraponera clavata (tocandira) and Dinoponera spp. (false tocandiras) of South America and the Myrmecia ants of Australia.
In South Africa, ants are used to help harvest the seeds of rooibos (Aspalathus linearis), a plant used to make a herb... | Ant | Wikipedia | 209 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are used in Mexican escamoles. They are considered a form of insect caviar and can sell for as much as US$50 per kg going up to US$200 per kg (as of 2006) because they are seasonal and hard to find. In the Colombian departm... | Ant | Wikipedia | 397 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Some ant species are considered as pests, primarily those that occur in human habitations, where their presence is often problematic. For example, the presence of ants would be undesirable in sterile places such as hospitals or kitchens. Some species or genera commonly categorized as pests include the Argentine ant, im... | Ant | Wikipedia | 481 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Some later commercial versions use transparent gel instead of soil, allowing greater visibility at the cost of stressing the ants with unnatural light.
In culture
Anthropomorphised ants have often been... | Ant | Wikipedia | 256 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his 1880 book A Tramp Abroad. Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "... | Ant | Wikipedia | 452 | 2594 | https://en.wikipedia.org/wiki/Ant | Biology and health sciences | Hymenoptera | null |
Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative measurement of chemical elements. AAS is based on the absorption of light by free metallic ions that have been atomized from a sample. An alternative technique is atomic emission spectroscopy (AES).
In analytical chemistry the... | Atomic absorption spectroscopy | Wikipedia | 485 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
The prepared solution is nebulized into a fine mist and introduced into a high-temperature flame (air-acetylene or nitrous oxide-acetylene mix).
The intense heat in the flame excites the electrons in the analyte atoms, promoting them to higher energy levels.
Step 3: Absorption:**
Simultaneously, a hollow cathode lam... | Atomic absorption spectroscopy | Wikipedia | 448 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
In order to analyze a sample for its atomic constituents, it has to be atomized. The atomizers most commonly used nowadays are flames and electrothermal (graphite tube) atomizers. The atoms should then be irradiated by optical radiation, and the radiation source could be an element-specific line radiation source or a ... | Atomic absorption spectroscopy | Wikipedia | 442 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
The processes in a flame include the stages of desolvation (drying) in which the solvent is evaporated and the dry sample nano-particles remain, vaporization (transfer to the gaseous phase) in which the solid particles are converted into gaseous molecule, atomization in which the molecules are dissociated into free ato... | Atomic absorption spectroscopy | Wikipedia | 449 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
The graphite tubes are heated via their ohmic resistance using a low-voltage high-current power supply; the temperature in the individual stages can be controlled very closely, and temperature ramps between the individual stages facilitate separation of sample components. Tubes may be heated transversely or longitudina... | Atomic absorption spectroscopy | Wikipedia | 413 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Glow-discharge atomization
A glow-discharge device (GD) serves as a versatile source, as it can simultaneously introduce and atomize the sample. The glow discharge occurs in a low-pressure argon gas atmosphere between 1 and 10 torr. In this atmosphere lies a pair of electrodes applying a DC voltage of 250 to 1000 V to ... | Atomic absorption spectroscopy | Wikipedia | 421 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Cold-vapor atomization
The cold-vapor technique is an atomization method limited only for the determination of mercury, due to it being the only metallic element to have a large vapor pressure at ambient temperature. Because of this, it has an important use in determining organic mercury compounds in samples and their ... | Atomic absorption spectroscopy | Wikipedia | 367 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Hollow cathode lamps
Hollow cathode lamps (HCL) are the most common radiation source in LS AAS. Inside the sealed lamp, filled with argon or neon gas at low pressure, is a cylindrical metal cathode containing the element of interest and an anode. A high voltage is applied across the anode and cathode, resulting in an ... | Atomic absorption spectroscopy | Wikipedia | 454 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Continuum sources
When a continuum radiation source is used for AAS, it is necessary to use a high-resolution monochromator, as will be discussed later. In addition, it is necessary that the lamp emits radiation of intensity at least an order of magnitude above that of a typical HCL over the entire wavelength range fr... | Atomic absorption spectroscopy | Wikipedia | 390 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Spectrometers for CS AAS
When a continuum radiation source is used for AAS measurement it is indispensable to work with a high-resolution monochromator. The resolution has to be equal to or better than the half-width of an atomic absorption line (about 2 pm) in order to avoid losses of sensitivity and linearity of the... | Atomic absorption spectroscopy | Wikipedia | 356 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Background absorption and background correction
The relatively small number of atomic absorption lines (compared to atomic emission lines) and their narrow width (a few pm) make spectral overlap rare; there are only few examples known that an absorption line from one element will overlap with another. Molecular absorp... | Atomic absorption spectroscopy | Wikipedia | 416 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Deuterium background correction
This is the oldest and still most commonly used technique, particularly for flame AAS. In this case, a separate source (a deuterium lamp) with broad emission is used to measure the background absorption over the entire width of the exit slit of the spectrometer. The use of a separate la... | Atomic absorption spectroscopy | Wikipedia | 336 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
An alternating magnetic field is applied at the atomizer (graphite furnace) to split the absorption line into three components, the π component, which remains at the same position as the original absorption line, and two σ components, which are moved to higher and lower wavelengths, respectively. Total absorption is me... | Atomic absorption spectroscopy | Wikipedia | 457 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
Background correction using a least-squares algorithm
The above technique can obviously not correct for a background with fine structure, as in this case the absorbance will be different at each of the correction pixels. In this case HR-CS AAS is offering the possibility to measure correction spectra of the molecule(s... | Atomic absorption spectroscopy | Wikipedia | 205 | 2637 | https://en.wikipedia.org/wiki/Atomic%20absorption%20spectroscopy | Physical sciences | Spectroscopy | Chemistry |
In optics, aberration is a property of optical systems, such as lenses, that causes light to be spread out over some region of space rather than focused to a point. Aberrations cause the image formed by a lens to be blurred or distorted, with the nature of the distortion depending on the type of aberration. Aberration ... | Optical aberration | Wikipedia | 511 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
Although defocus is technically the lowest-order of the optical aberrations, it is usually not considered as a lens aberration, since it can be corrected by moving the lens (or the image plane) to bring the image plane to the optical focus of the lens.
In addition to these aberrations, piston and tilt are effects whic... | Optical aberration | Wikipedia | 352 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
The investigations of James Clerk Maxwell and Ernst Abbe showed that the properties of these reproductions, i.e., the relative position and magnitude of the images, are not special properties of optical systems, but necessary consequences of the supposition (per Abbe) of the reproduction of all points of a space in ima... | Optical aberration | Wikipedia | 466 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
The largest opening of the pencils, which take part in the reproduction of O, i.e., the angle u, is generally determined by the margin of one of the lenses or by a hole in a thin plate placed between, before, or behind the lenses of the system. This hole is termed the stop or diaphragm; Abbe used the term aperture sto... | Optical aberration | Wikipedia | 341 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
Aberration of elements, i.e. smallest objects at right angles to the axis
If rays issuing from O (fig. 1) are concurrent, it does not follow that points in a portion of a plane perpendicular at O to the axis will be also concurrent, even if the part of the plane be very small. As the diameter of the lens increases (i.... | Optical aberration | Wikipedia | 363 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
A point O (fig. 2) at a finite distance from the axis (or with an infinitely distant object, a point which subtends a finite angle at the system) is, in general, even then not sharply reproduced if the pencil of rays issuing from it and traversing the system is made infinitely narrow by reducing the aperture stop; such... | Optical aberration | Wikipedia | 442 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
Sir Isaac Newton was probably the discoverer of astigmation; the position of the astigmatic image lines was determined by Thomas Young; and the theory was developed by Allvar Gullstrand. A bibliography by P. Culmann is given in Moritz von Rohr's Die Bilderzeugung in optischen Instrumenten.
Aberration of lateral objec... | Optical aberration | Wikipedia | 330 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
Even if the image is sharp, it may be distorted compared to ideal pinhole projection. In pinhole projection, the magnification of an object is inversely proportional to its distance to the camera along the optical axis so that a camera pointing directly at a flat surface reproduces that flat surface. Distortion can be... | Optical aberration | Wikipedia | 219 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
This aberration is quite distinct from that of the sharpness of reproduction; in unsharp, reproduction, the question of distortion arises if only parts of the object can be recognized in the figure. If, in an unsharp image, a patch of light corresponds to an object point, the center of gravity of the patch may be regar... | Optical aberration | Wikipedia | 475 | 2704 | https://en.wikipedia.org/wiki/Optical%20aberration | Physical sciences | Optics | Physics |
Autocorrelation, sometimes known as serial correlation in the discrete time case, is the correlation of a signal with a delayed copy of itself as a function of delay. Informally, it is the similarity between observations of a random variable as a function of the time lag between them. The analysis of autocorrelation is... | Autocorrelation | Wikipedia | 422 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
Definition for wide-sense stationary stochastic process
If is a wide-sense stationary process then the mean and the variance are time-independent, and further the autocovariance function depends only on the lag between and : the autocovariance depends only on the time-distance between the pair of values but not on... | Autocorrelation | Wikipedia | 512 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
The (potentially time-dependent) autocorrelation matrix (also called second moment) of a (potentially time-dependent) random vector is an matrix containing as elements the autocorrelations of all pairs of elements of the random vector . The autocorrelation matrix is used in various digital signal processing algorithm... | Autocorrelation | Wikipedia | 510 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
For processes that are also ergodic, the expectation can be replaced by the limit of a time average. The autocorrelation of an ergodic process is sometimes defined as or equated to
These definitions have the advantage that they give sensible well-defined single-parameter results for periodic functions, even when those... | Autocorrelation | Wikipedia | 490 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
Efficient computation
For data expressed as a discrete sequence, it is frequently necessary to compute the autocorrelation with high computational efficiency. A brute force method based on the signal processing definition can be used when the signal size is small. For example, to calculate the autocorrelation of the r... | Autocorrelation | Wikipedia | 418 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
for any positive integer . When the true mean and variance are known, this estimate is unbiased. If the true mean and variance of the process are not known there are several possibilities:
If and are replaced by the standard formulae for sample mean and sample variance, then this is a biased estimate.
A periodogr... | Autocorrelation | Wikipedia | 320 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
In ordinary least squares (OLS), the adequacy of a model specification can be checked in part by establishing whether there is autocorrelation of the regression residuals. Problematic autocorrelation of the errors, which themselves are unobserved, can generally be detected because it produces autocorrelation in the obs... | Autocorrelation | Wikipedia | 510 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
Applications
Autocorrelation's ability to find repeating patterns in data yields many applications, including:
Autocorrelation analysis is used heavily in fluorescence correlation spectroscopy to provide quantitative insight into molecular-level diffusion and chemical reactions.
Another application of autocorrelation... | Autocorrelation | Wikipedia | 492 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
Autocorrelation in space rather than time, via the Patterson function, is used by X-ray diffractionists to help recover the "Fourier phase information" on atom positions not available through diffraction alone.
In statistics, spatial autocorrelation between sample locations also helps one estimate mean value uncertain... | Autocorrelation | Wikipedia | 303 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
Serial dependence
Serial dependence is closely linked to the notion of autocorrelation, but represents a distinct concept (see Correlation and dependence). In particular, it is possible to have serial dependence but no (linear) correlation. In some fields however, the two terms are used as synonyms.
A time series of... | Autocorrelation | Wikipedia | 135 | 2724 | https://en.wikipedia.org/wiki/Autocorrelation | Mathematics | Statistics | null |
AutoCAD is a 2D and
3D computer-aided design (CAD) software application developed by Autodesk. It was first released in December 1982 for the CP/M and IBM PC platforms as a desktop app running on microcomputers with internal graphics controllers. Initially a DOS application, subsequent versions were later released for... | AutoCAD | Wikipedia | 420 | 2753 | https://en.wikipedia.org/wiki/AutoCAD | Technology | Science and Engineering | null |
Compatibility with other software
Many software applications such as Autodesk Civil 3D and ESRI ArcMap 10 permits export as AutoCAD drawing files. Third-party file converters exist for specific formats such as Bentley MX GENIO Extension, PISTE Extension (France), ISYBAU (Germany), OKSTRA and Microdrainage (UK); also, ... | AutoCAD | Wikipedia | 506 | 2753 | https://en.wikipedia.org/wiki/AutoCAD | Technology | Science and Engineering | null |
Additional tools generate standard 2D drawings, such as elevations and sections, from a 3D architectural model. Similarly, Civil Design, Civil Design 3D, and Civil Design Professional support data-specific objects facilitating easy standard civil engineering calculations and representations.
Softdesk Civil was develop... | AutoCAD | Wikipedia | 411 | 2753 | https://en.wikipedia.org/wiki/AutoCAD | Technology | Science and Engineering | null |
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