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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Pre-Existence
Pre-existence, preexistence, beforelife, or premortal existence refers to the belief that each individual human soul existed before mortal conception, and at some point before birth enters or is placed into the body. Concepts of pre-existence can encompass either the belief that the soul came into existence at some time prior to conception or the belief that the soul is eternal. Alternative positions are traducianism and creationism, which both hold that the individual human soul does not come into existence until conception. It is to be distinguished from preformation, which is about physical existence and applies to all living things. Ancient Greek thought and Islam affirm pre-existence, but it is generally denied in Christianity.
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  • 08 Nov 2022
Topic Review
Zagros Fold and Thrust Belt
The Zagros fold and thrust belt (Zagros FTB) is an approximately 1,800-kilometre (1,100 mi) long zone of deformed crustal rocks, formed in the foreland of the collision between the Arabian Plate and the Eurasian Plate. It is host to one of the world's largest petroleum provinces, containing about 49% of the established hydrocarbon reserves in fold and thrust belts and about 7% of all reserves globally.
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  • 08 Nov 2022
Topic Review
List of Polychaete Worms of South Africa
The list of polychaete worms of South Africa is a list of species that form a part of the class Polychaeta (Phylum Annelida) fauna of South Africa. The list follows the SANBI listing. 
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  • 08 Nov 2022
Topic Review
Spawn
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mosquitoes and corals, which are actually small aquatic animals—not plants. Fungi, such as mushrooms, are also said to "spawn" a white, fibrous matter that forms the matrix from which they grow. There are many variations in the way spawning occurs, depending on sexual differences in anatomy, how the sexes relate to each other, where and how the spawn is released and whether or how the spawn is subsequently guarded.
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  • 08 Nov 2022
Topic Review
Oregon Badlands Wilderness
The Oregon Badlands Wilderness is a 29,301-acre (11,858 ha) wilderness area located east of Bend in Deschutes and Crook counties in the U.S. state of Oregon. The wilderness is managed by the Bureau of Land Management as part of the National Landscape Conservation System and was created by the Omnibus Public Land Management Act of 2009, which was signed into law by President Barack Obama on 30 March 2009. The area is known for igneous castle-like rock formations, harsh terrain, ancient Juniper trees, sagebrush, and extensive arid land. Desert wildflowers, dry river canyons, and Native American pictographs can be found. The blind iditarod racer Rachel Scdoris trained in the area, and the wilderness is home to the western terminus of the Oregon Desert Trail.
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  • 08 Nov 2022
Topic Review
PledgeMusic
PledgeMusic is an online direct-to-fan music platform, launched in August 2009, that facilitates musicians reaching out to their fanbase (termed Pledgers) to pre-sell, market, and distribute music projects including recordings, music videos, and concerts. Broadly speaking it bears some similarities to such platforms as ArtistShare, Kickstarter, Indiegogo, Patreon, RocketHub and Sellaband.
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  • 08 Nov 2022
Topic Review
Containment Building
A containment building, in its most common usage, is a reinforced steel, concrete or lead structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of 275 to 550 kPa (40 to 80 psi) . The containment is the fourth and final barrier to radioactive release (part of a nuclear reactor's defence in depth strategy), the first being the fuel ceramic itself, the second being the metal fuel cladding tubes, the third being the reactor vessel and coolant system. Each nuclear plant in the US is designed to withstand certain conditions which are spelled out as "Design Basis Accidents" in the Final Safety Analysis Report (FSAR). The FSAR is available for public viewing, usually at a public library near the nuclear plant. The containment building itself is typically an airtight steel structure enclosing the reactor normally sealed off from the outside atmosphere. The steel is either free-standing or attached to the concrete missile shield. In the United States , the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture. While the containment plays a critical role in the most severe nuclear reactor accidents, it is only designed to contain or condense steam in the short term (for large break accidents) and long term heat removal still must be provided by other systems. In the Three Mile Island accident the containment pressure boundary was maintained, but due to insufficient cooling, some time after the accident, radioactive gas was intentionally let from containment by operators to prevent over pressurization. This, combined with further failures, caused the release of up to 13 million curies of radioactive gas to atmosphere during the accident. While the Fukushima Daiichi plant had operated safely since 1971, an earthquake and tsunami well beyond the design basis resulted in failure of AC power, backup generators and batteries which defeated all safety systems. These systems were necessary to keep the fuel cool after the reactor had been shut down. This resulted in partial or complete meltdown of fuel rods, damage to fuel storage pools and buildings, release of radioactive debris to surrounding area, air and sea, and resorting to the expedient use of fire engines and concrete pumps to deliver cooling water to spent fuel pools and containment. During the incident, pressure within the containments of reactors 1-3 rose to exceed design limits, which despite attempts to reduce pressure by venting radioactive gases, resulted in breach of containment. Hydrogen leaking from the containment mixed with air into an explosive mixture which resulted in explosions in Unit 1, 3 and 4, complicating attempts to stabilize the reactors.
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  • 08 Nov 2022
Topic Review
Rikhter R-23
The Rikhter R-23 is an aircraft autocannon developed for the Soviet Air Force starting in the late 1950s. It was designed to be as short as possible to avoid problems found on high-speed aircraft when the guns were pointed into the airstream. The R-23 was a gas operated revolver cannon that used gas bled from holes in the barrel to provide the motive force. Firing up to 2,600 rpm, the R-23 was the fastest firing single-barrel cannon ever introduced into service. The R-23 took some time to develop, and was not used operationally until 1964. It was used only in the tail turret of the Tu-22, and experimentally on the Salyut 3 space station. Its role was taken over by the twin-barrel Gryazev-Shipunov GSh-23. A modified version of the weapon was the only cannon to have been fired in space.
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  • 08 Nov 2022
Topic Review
Enzymatical Processes
Enzymatical processes topic wants to enhance the central role of enzymes, the real workers from whose silent and tireless work depends the well-being of all cells in fact, intra-cellular reactions that take place in the cells are facilitated and therefore accelerated by enzymes.
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Topic Review
Virus Information Table
Viruses are extremely diverse in nature. Even their method of storing genetic information differs tremendously, from double-stranded DNA to negative sense RNA, as denoted in the Baltimore Classification System. Other features, such as entry and release details, or capsid structure may be important in classifying and understanding viruses.
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