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LipidFrom Wikipedia, the free encyclopedia Jump to: navigation, search A polyunsaturated triglyceride. Left: glycerol, right, from top to bottom: palmitic acid, oleic acid, alpha-linolenic acid, chemical formula: C55H98O6Lipids are an amphiphilic class of hydrocarbon-containing organic compounds. Lipids are categorized by the fact that they have complicated solvation properties, giving rise to lipid polymorphism. Lipid molecules have these properties because they consist largely of long hydrocarbon tails which are lipophilic in nature as well as polar headgroups (e.g. phosphate-based functionality, and/or inositol based functionality). In living organisms, lipids are used for energy storage, serve as the structural components of cell membranes, and constitute important signalling molecules. Although the term lipid is often used as a synonym for fat, the latter is in fact a subgroup of lipids called triglycerides.

Contents [hide] 1 Structure 1.1 Fatty acids and glycerides 2 Nutrition and health 3 References 4 See also 5 External links

[edit] Structure

[edit] Fatty acids and glycerides Main article: fatty acid

Chemically, fatty acids can be described as long-chain monocarboxylic acids and have a general structure of CH3(CH2)nCOOH. The length of the chain usually ranges from 12 to 24, always with an even number of carbons. When the carbon chain contains no double bonds, it is a saturated chain. If it contains one or more such bonds, it is unsaturated. The presence of double bonds generally reduces the melting point of fatty acids. Furthermore, unsaturated fatty acids can occur either in cis or trans geometric isomers. In naturally occurring fatty acids, the double bonds are in the cis-configuration.

Glycerides are lipids possessing a glycerol (propan-1, 2, 3-triol) core structure with one or more fatty acyl groups, which are fatty acid-derived chains attached to the glycerol backbone by ester linkages. Glycerides with three acyl groups (triglycerides or neutral fats) are the main storage form of fat in animals and plants.

An important type of glyceride-based molecule found in biological membranes, such as the cell's plasma membrane and the intracellular membranes of organelles, are the phosphoglycerides or glycerophospholipids. These are phospholipids that contain a glycerol core linked to two fatty acid-derived "tails" by ester or, more rarely, ether linkages and to one "head" group by a phosphate ester linkage. The head groups of the phospholipids found in biological membranes are phosphatidylcholine (also known as PC, and lecithin), phosphatidylethanolamine (PE), phosphatidylserine and phosphatidylinositol (PI). These phospholipids are subject to a variety of functions in the cell: for instance, the lipophilic and polar ends can be released from specific phospholipids through enzyme-catalysed hydrolysis to generate secondary messengers involved in signal transduction. In the case of phosphatidylinositol, the head group can be enzymatically modified by the addition of one, two or three phosphate groups, this constituting another mechanism of cell signalling. While phospholipids are the major component of biological membranes, other non-glyceride lipid components like sphingolipids and sterols (such as cholesterol in animal cell membranes) are also found in biological membranes.

A biological membrane is a form of lipid bilayer, as is a liposome. Formation of lipid bilayers is an energetically-favoured process when the glycerophospholipids described above are in an aqueous environment. In an aqueous system, the polar heads of lipids orientate towards the polar, aqueous environment, while the hydrophobic tails minimise their contact with water. The lipophilic tails of lipids (U) tend to cluster together, forming a lipid bilayer (1) or a micelle (2). Other aggregations are also observed and form part of the polymorphism of amphiphile (lipid) behaviour. The polar heads (P) face the aqueous environment, curving away from the water. Phase behaviour is a complicated area within biophysics and is the subject of current academic research.

Micelles and bilayers form in the polar medium by a process known as the lipophilic effect. When dissolving a lipophilic or amphiphilic substance in a polar environment, the polar molecules (i.e. water in an aqueous solution) become more ordered around the dissolved lipophilic substance, since the polar molecules cannot form hydrogen bonds to the lipophilic areas of the amphiphile. So, in an aqueous environment the water molecules form an ordered "clathrate" cage around the dissolved lipophilic molecule.

Figure 2: Self-organization of phospholipids. A lipid bilayer is shown on the left and a micelle on the right.The self-organisation depends on the concentration of the lipid present in solution. Below the critical micelle concentration, the lipids form a single layer on the liquid surface and are (sparingly) dispersed in the solution. At the first critical micelle concentration (CMC-I), the lipids organise in spherical micelles, at given points above this concentration, other phases are observed (see lipid polymorphism).

[edit] Nutrition and health Lipids play diverse and important roles in nutrition and health. Many lipids are absolutely essential for life, however, there is also considerable awareness that abnormal levels of certain lipids, particularly cholesterol (in hypercholesterolemia) and, more recently, trans fatty acids, are risk factors for heart disease and other diseases. We need fats in our bodies and in our diet. Animals in general use fat for energy storage because fat stores 9 KCal/g of energy. Plants, which don’t move around, can afford to store food for energy in a less compact but more easily accessible form, so they use starch (a carbohydrate, NOT A LIPID) for energy storage. Carbohydrates and proteins store only 4 KCal/g of energy, so fat stores over twice as much energy/gram as other sources of energy. Citation needed

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area51Area 51 From Wikipedia, the free encyclopedia Jump to: navigation, search Editing of this article by unregistered or newly registered users is currently disabled. If you are prevented from editing this article, and you wish to make a change, please discuss changes on the talk page, request unprotection, log in, or create an account.

This article is about the U.S. Air Force installation in Nevada. For other uses, see Area 51 (disambiguation). Landsat pseudocolor satellite photo of Groom Lake, taken around 2000Area 51 (officially known as Air Force Flight Test Center, Detachment 3 and also known as Dreamland, Watertown Strip, Paradise Ranch, The Box, Groom Lake, Neverland, and other names) is a remote tract of land in the southwestern portion of Lincoln County in southern Nevada, located at 37°14′20″N 115°48′58″W﻿ / ﻿37.239, -115.816, at the southern edge of a large dry salt flat called Groom Lake. It lies within the Nevada Test and Training Range and is owned by the United States Department of Defense and the United States Air Force. Area 51 contains an airfield whose primary purpose is believed to be the operation and analysis of enemy aircraft and weapons systems, and secret development and testing of new military aircraft.[citation needed] Area 51 is the frequent subject of UFO conspiracy theories.

Contents [hide] 1 Runways 2 Geography 3 Operations at Groom Lake 3.1 Senior Year/U-2 program 3.2 Blackbird programs 3.3 Have Blue/Senior Trend/F-117 program 4 Area 51 commuters 5 The government's position on Area 51 5.1 Environmental lawsuit 5.2 1974 Skylab photography 6 UFO and other conspiracy theories concerning Area 51 7 Area 51 in popular culture 7.1 Television series 7.2 Movies 7.3 Books 7.4 Computer and video games 7.5 Music 7.6 Role-playing games 7.7 Other 8 See also 9 References 9.1 General references 9.2 Specific references 10 External links

Runways Paved

14L-32R 14R 32L 03R-21L 03L-21R Sand

9L-27R 9R-27L The sand runways are only used in the event of very high crosswinds or an emergency.

Geography Map showing Area 51, NAFR, and the NTSArea 51 shares a border with the Yucca Flats region of the Nevada Test Site (NTS), the location of many of the US Department of Energy's nuclear weapons tests. The Yucca Mountain nuclear storage facility is approximately 40 miles (64km) southwest of Groom Lake.

The designation "Area 51" is somewhat contentious, appearing on older maps of the NTS but not newer ones, but the same naming scheme is used for other parts of the Nevada Test Site.

The area is connected to the internal NTS road network, with paved roads leading both to Mercury, to the northwest, and west to Yucca Flats. Leading northeast from the lake, the wide and well-maintained Groom Lake Road runs through a pass in the Jumbled Hills. The road formerly led to mines in the Groom basin, but has been improved since their closure. Its winding course runs past a security checkpoint, but the restricted area around the base extends further east. (Unauthorized visitors who travel west on Groom Lake Road are usually observed first by guards located on the hills surrounding the pass, still several miles from the checkpoint). After leaving the restricted area (marked by numerous warning signs stating that "photography is prohibited" and that "use of deadly force is authorized" under the terms of the 1950 McCarran Internal Security Act) Groom Lake Road descends eastward to the floor of the Tikaboo Valley, passing the dirt-road entrances to several small ranches, before converging with Nevada State Route 375, the "Extraterrestrial Highway", south of Rachel.

Operations at Groom Lake Satellite view of Area 51 from 1968.Groom Lake is not a conventional airbase, as frontline units are not normally deployed there. It instead appears to be used during the development, testing, and training phases for new aircraft. Once these aircraft have been approved by the United States Air Force, operation of that aircraft is generally conducted as that of a normal air force base. Groom is reported, however, to be the permanent home for a small number of Soviet-designed aircraft (obtained by various means), which are reportedly analyzed and used for training purposes.

Soviet spy satellites obtained photographs of the Groom Lake area during the height of the Cold War, but these support only modest conclusions about the base. The photos depict a nondescript base, airstrip, hangars and the like, but nothing that supports some of the wilder claims about underground facilities. Commercial satellite images show that the base has since grown but remained ostensibly unexceptional.

Senior Year/U-2 program Groom Lake was used for bombing and artillery practice during World War II, but was then abandoned until 1955, when it was selected by Lockheed's Skunk Works team as the ideal location to test the forthcoming U-2 spy plane. The lakebed made an ideal strip from which they could operate the troublesome test aircraft, and the Emigrant Valley's mountain ranges and the NTS perimeter protected the secret plane from curious eyes.

Lockheed constructed a makeshift base at Groom, consisting of little more than a few shelters, workshops and trailer homes in which to billet its small team. The first U-2 flew at Groom in August 1955, and U-2s under the control of the CIA began overflights of Soviet territory by mid-1956.

During this period, the NTS continued to perform a series of atmospheric nuclear explosions. U-2 operations throughout 1957 were frequently disrupted by the Plumbbob series of atomic tests, which detonated over two dozen devices at the NTS. The Plumbbob-Hood explosion on July 5 scattered fallout across Groom and forced a temporary evacuation.

As the U-2's primary mission was to fly over the Soviet Union, it operated largely from airbases near the Soviet border, including Incirlik in Turkey and Peshawar in Pakistan, and in Bodø, Norway.

Blackbird programs Even before U-2 development was complete, Lockheed began work on its successor, the CIA's OXCART project, a Mach-3 high altitude reconnaissance aircraft, a later variant of that which became the famed USAF SR-71 Blackbird. The Blackbird's flight characteristics and maintenance requirements forced a massive expansion of facilities and runways at Groom Lake. By the time the first A-12 Blackbird prototype flew at Groom in 1962, the main runway had been lengthened to 8500ft. (2600m), and the base boasted a complement of over 1000 personnel. It had fueling tanks, a control tower and baseball diamond. Security was greatly enhanced, the small civilian mine in the Groom basin was closed, and the area surrounding the valley was made an exclusive military preserve (where interlopers could be subject to "lethal force"). Groom saw the first flight of all major Blackbird variants: A-12, SR-71, its abortive YF-12 interceptor variant, and the D-21 Blackbird-based drone project.

Have Blue/Senior Trend/F-117 program The first Have Blue prototype stealth fighter (a smaller cousin of the F-117 Nighthawk commonly seen and reported as a "UFO") first flew at Groom in late 1977. Testing of a series of ultra-secret prototypes continued there until mid-1981, when testing transitioned to the initial production of F-117 stealth fighters. In addition to flight testing, Groom performed radar profiling, F-117 weapons testing, and was the location for training of the first group of frontline USAF F-117 pilots. Subsequently, the still highly classified active-service F-117 operations moved to the nearby Tonopah Test Range, and finally to Holloman Air Force Base.

Area 51 commuters Defense contractor EG&G maintains a private terminal at McCarran International Airport in Las Vegas. A number of unmarked aircraft operate daily shuttle services from McCarran to sites operated by EG&G in the extensive federally controlled lands in southern Nevada. These aircraft reportedly use JANET radio call signs (e.g., "JANET 6"), said to be an acronym for "Joint Air Network for Employee Transportation" or (perhaps jokingly) "Just Another Non-Existent Terminal". EG&G advertises in the Las Vegas press for experienced airline pilots, requiring applicants to be eligible for government security clearance and that successful applicants can expect to always stay overnight at Las Vegas. These aircraft, painted white with red trim (the livery of now defunct Western Airlines), include six Boeing 737/T-43As and several smaller turboprops. Their tail numbers are registered to the U.S. Air Force. They are reported to shuttle to Groom, Tonopah Test Range, to other locations in the NAFR and NTS, and reportedly to Naval Air Weapons Station China Lake. Observers tracking the number of departures and cars in the private EG&G parking lot at McCarran estimate several thousand JANET commuters each day. These shuttle flights were previously operated by Key Air, which had flown 22,000 passenger trips on 300 flights from Nellis Air Force Base to Tonopah Test Range per month from 1982 until early 1991.

A bus runs a commuter service along Groom Lake Road, catering to a small number of employees living in several small desert communities beyond the NTS boundary (although it is not clear whether these workers are employed at Groom or at other facilities in the NTS). The bus drives down Groom Lake Road and stops at Crystal Springs, Ash Springs, and Alamo, and parks in front of the Alamo court house overnight.

The government's position on Area 51 A letter from the USAF replying to a query about Area 51In 1997 the U.S. Government declassified the existence of Area 51. Unlike much of the Nellis range, the area surrounding the lake is permanently off-limits both to civilians and normal military air traffic. The area is protected by radar stations, and unauthorized personnel are quickly expelled. Even military pilots training in the NAFR are reportedly interrogated extensively by military intelligence agents when they accidentally stray into the exclusionary "box" surrounding Groom's airspace.[citation needed]

A montage of available USGS satellite photography showing southern Nevada. The NTS and the surrounding lands are visible; the NAFR and neighboring land has been removedPerimeter security is provided by uniformed private security guards working for EG&G's security subcontractor Wackenhut,[1] who patrol in desert camouflage Jeep Cherokee and Hum-Vee vehicles, and more recently, champagne-colored Ford F-150 pickups and gray Chevy 2500 4X4 pickups. Although the guards are armed with M16s, no violent encounters with Area 51 observers have been reported; instead, the guards generally follow visitors near the perimeter and radio for the Lincoln County sheriff. Deadly force is authorized if violators who attempt to breach the secured area fail to heed warnings to halt. Fines of around $600 seem to be the normal course of action, although some visitors and journalists report receiving follow-up visits from FBI agents. Some observers have been detained on public land for pointing camera equipment at the base. Surveillance is supplemented using buried motion sensors and by HH-60 Pave Hawk helicopters.

Partial view of the Groom Lake lakebed and the Air Force Flight Test Center, Detachment 3 facilities as seen on Google Maps.The base does not appear on public U.S. government maps; the USGS topological map for the area only shows the long-disused Groom Mine[citation needed], and the civil aviation chart for Nevada shows a large restricted area, but defines it as part of the Nellis restricted airspace. Similarly the National Atlas page showing federal lands in Nevada[2] does not distinguish between the Groom block and other parts of the Nellis range. Although officially declassified, the original film taken by U.S. Corona spy satellite in the 1960s has been altered prior to declassification; in answer to freedom of information queries, the government responds that these exposures (which map to Groom and the entire NAFR) appear to have been destroyed.[3] Terra satellite images (which were publicly available) were removed from webservers (including Microsoft's "Terraserver") in 2004,[4] and from the monochrome 1 m resolution USGS datadump made publicly available. NASA Landsat 7 images are still available (these are used in the NASA World Wind). Non-U.S. images, including high-resolution photographs from Russian satellites and the commercial IKONOS system, are also easily available (and abound on the Internet). Perhaps the best, most detailed images widely available to the public exist on Google Earth, which shows in considerable detail the runway marking, base facilities, planes, and vehicles.

Extraterrestrial Highway signNevada's state government, recognizing the folklore surrounding the base might afford the otherwise neglected area some tourism potential, officially renamed the section of Nevada State Route 375 near Rachel "The Extraterrestrial Highway", and posted fancifully illustrated signs along its length.

Although federal property within the base is exempt from state and local taxes, facilities owned by private contractors are not. One researcher has reported that the base only declares a taxable value of $2 million to the Lincoln County tax assessor, who is unable to enter the area to perform an assessment.

Environmental lawsuit In 1994, five unnamed civilian contractors and the widows of contractors Walter Kasza and Robert Frost sued the USAF and the Environmental Protection Agency. Their suit, in which they were represented by George Washington University law professor Jonathan Turley, alleged they had been present when large quantities of unknown chemicals had been burned in open pits and trenches at Groom. Biopsies taken from the complainants were analyzed by Rutgers University biochemists, who found high levels of dioxin, dibenzofuran, and trichloroethylene in their body fat. The complainants alleged they had sustained skin, liver, and respiratory injuries due to their work at Groom, and that this had contributed to the deaths of Frost and Kasza. The suit sought compensation for the injuries they had sustained, claiming the USAF had illegally handled toxic materials, and that the EPA had failed in its duty to enforce the Resource Conservation and Recovery Act (which governs handling of dangerous materials). They also sought detailed information about the chemicals to which they were allegedly exposed, hoping this would facilitate the medical treatment of survivors. Congressman Lee H. Hamilton, former chairman of the House Intelligence Committee, told 60 Minutes reporter Leslie Stahl "The Air Force is classifying all information about Area 51 in order to protect themselves from a lawsuit."[5]

Citing the State Secrets Privilege, the government petitioned trial judge U.S. District Judge Philip Pro (of the United States District Court for the District of Nevada in Las Vegas) to disallow disclosure of classified documents or examination of secret witnesses, alleging this would expose classified information and threaten national security. When Judge Pro rejected the government's argument, President Bill Clinton issued a Presidential Determination, exempting what it called, "The Air Force's Operating Location Near Groom Lake, Nevada" from environmental disclosure laws. Consequently, Pro dismissed the suit due to lack of evidence. Turley appealed to the U.S. Court of Appeals for the Ninth Circuit, on the grounds that the government was abusing its power to classify material. Secretary of the Air Force Sheila E. Widnall filed a brief which stated that disclosures of the materials present in the air and water near Groom, "Can reveal military operational capabilities or the nature and scope of classified operations." The Ninth Circuit rejected Turley's appeal,[6] and the U.S. Supreme Court refused to hear it, putting an end to the complainants' case.

The President continues to annually issue a determination continuing the Groom exception.[7][8][9] This, and similarly tacit wording used in other government communications, is the only formal recognition the U.S. Government has ever given that Groom Lake is more than simply another part of the Nellis complex.

1974 Skylab photography In January of 2006, aviation journalist Dwayne Day published an article in online aerospace magazine The Space Review titled "Astronauts and Area 51: the Skylab Incident." The article was based around a recently declassified memo written in 1974 to CIA director William Colby by an unknown CIA official. The memo reported that astronauts on board Skylab 4 had, as part of a larger program, inadvertently photographed a location of which the memo said "There were specific instructions not to do this. was the only location which had such an instruction." Although the name of the location was obscured, the context led Day to believe that the subject was Groom Lake.[10][11]

The memo details debate between federal agencies regarding whether the images should be classified, with Department of Defense agencies arguing that it should, and NASA and the State Department arguing against classification. The memo itself questions the legality of unclassified images to be retroactively classified.

Remarks on the memo,[12] handwritten apparently by DCI (Director of Central Intelligence) Colby himself, read:

He did raise it - said State Dept. people felt strongly. But he inclined leave decision to me (DCI) - I confessed some question over need to protect since: USSR has it from own sats What really does it reveal? If exposed, don't we just say classified USAF work is done there? The declassified documents do not disclose the outcome of discussions regarding the Skylab imagery, but were not placed in the federal government's archive of satellite imagery along with the remaining Skylab 4 photographs.

UFO and other conspiracy theories concerning Area 51 Its secretive nature and undoubted connection to classified aircraft research, together with reports of unusual phenomena, have led Area 51 to become a focus of modern UFO and conspiracy theory. Some of the unconventional activities claimed to be underway at Area 51 include:

The storage, examination, and reverse engineering of crashed alien spacecraft (including material supposedly recovered at Roswell), the study of their occupants (living and dead), and the manufacture of aircraft based on alien technology. Meetings or joint undertakings with extraterrestrials. The development of exotic energy weapons (for SDI applications or otherwise) or means of weather control. The development of time travel technology. Activities related to a supposed shadowy one world government. Many of the hypotheses concern underground facilities at Groom or at nearby Papoose Lake, and include claims of a transcontinental underground railroad system, a disappearing airstrip (nicknamed the "Cheshire Airstrip", after Lewis Carroll's Cheshire cat) which briefly appears when water is sprayed onto its camouflaged asphalt,[13] and engineering based on alien technology. In 1989, Bob Lazar claimed that he had worked at a facility at Papoose Lake (which he called S-4) on such a U.S. Government flying saucer. One major hypothesis is that Area 51 is a place which simulates the environment of the moon. In 2000-2001, Fox Television broadcast a show about Apollo moon landing hoax accusations, in which it was suggested that the whole moon landing in 1969 was a hoax and was filmed in parts of Area 51.

A screenshot of Victor's alien interrogation video.Others, however, claim that during the mid 1990s, the most secret work previously done at Groom was quietly moved to other facilities, including Dugway Proving Ground in Utah, and that the continued secrecy around Groom is largely a successful attempt at misdirection.[14]

In July 1996, a man named Victor came forward and said on Art Bell's Coast to Coast AM radio show that he had a videotape of an alien interrogation. He said that he copied the tape and smuggled the copy out of Area 51. The video showed the head of an alien in a dark room, possibly using telepathy to communicate with military personnel and scientists[15] and was eventually included in a documentary entitled Area 51: The Alien Interview.

Area 51 in popular culture

Television series The Groom Lake base is featured in episodes of the following television series:

American Dad, Codename: Kids Next Door where there is an operative known as Numbuh 51, CSI: Crime Scene Investigation, Family Guy, Futurama, Jimmy Neutron Boy Genius as Area 86, Kim Possible, Megas XLR as Area 50, NewsRadio as Area 52, Seven Days as Never Never Land, The Simpsons as Area 51A, Sonic X as Area 99, Stargate Atlantis, Stargate SG-1, Star Trek: Deep Space Nine, Taken, Teenage Mutant Ninja Turtles, Tracker, The X-Files.