Summary

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.

Expand All
Entries
Topic Review
D-10 Tank Gun
The D-10 is a Soviet 100 mm tank gun developed in late World War II. It originally equipped the SU-100 tank destroyers and was later selected for the T-55 tank, equipping these as late as 1979. On the T-55 the D-10 continues to be in active service in many countries.
  • 6.0K
  • 19 Oct 2022
Topic Review
Evolution of Domestic Goats
Goat evolution is the process by which domestic goats came to exist through evolution by natural selection. Wild goats — medium-sized mammals which are found in noticeably harsh environments, particularly forests and mountains, in the Middle East and Central Asia — were one of the first species domesticated by modern humans, with the date of domestication generally considered to be 8,000 BCE. Goats are part of the family Bovidae, a broad and populous group which includes a variety of ruminants such as bison, cows and sheep. Bovids all share many traits, such as hooves and a herbivorous diet and all males, along with many females, have horns. Bovids began to diverge from deer and giraffids during the early Miocene epoch. The subfamily Caprinae, which includes goats, ibex and sheep, are considered to have diverged from the rest of Bovidae as early as the late Miocene, with the group reaching its greatest diversity in the ice ages. The tribe Caprini would subsequently develop from Caprids who arrived in the mountainous areas of Eurasia and split into goats and sheep in response to a further geographic separation. The ancestors of sheep remained in the foothills and the ancestors of goats went to higher altitudes. This divergence resulted in the adaption of the ancestors of goats to a mountainous environment, producing many of the traits considered peculiar to the species. During the ice ages a genus called Capri evolved which would then diverge into the modern goat species, along with several species of ibex. It is commonly held that the earliest domestication was of the bezoar ibex in the Zagros Mountains. These earliest domesticated goats were used to produce meat and milk for Neolithic farmers, along with providing many of the materials required to built residences and tools. Following the domestication of goats over 300 breeds have been established for a variety of purposes, including for the maximation of milk production and for meat. Domestication and the selective breeding which resulted had a significant effect on the direction of goat evolution, with goats developing behaviour which is considered to have been influenced by consistent proximity to humans. Selective breeding also significantly increased the physical diversity of modern goats, producing characteristics not seen in wild goats.
  • 3.4K
  • 08 Oct 2023
Topic Review
(486958) 2014 MU69
(486958) 2014 MU69, previously designated PT1 and 1110113Y, and nicknamed Ultima Thule by the New Horizons team, is a trans-Neptunian object from the Kuiper belt located in the outermost regions of the Solar System. It was discovered by astronomers using the Hubble Space Telescope on 26 June 2014. The irregular shaped classical Kuiper belt object is a suspected contact binary or close binary system and measures approximately 30 kilometers (19 miles) in diameter. In August 2015, this object was selected as the next target for the New Horizons probe shortly after it had visited Pluto. The flyby will occur on 1 January 2019, which will make it the farthest object in the Solar System ever to be visited by a spacecraft. After four course changes in October and November 2015, New Horizons is on course toward 2014 MU69. On 13 March 2018, NASA announced that (486958) 2014 MU69 would receive the nickname Ultima Thule. The decision was based on the results of a public voting campaign. Ultima Thule /ˈθuːliː/, or Ultima for short, serves as an unofficial name for the object until the IAU decides on an official name at some point after the flyby.
  • 1.0K
  • 19 Oct 2022
Topic Review
Mortal Kombat
Mortal Kombat is an American media franchise centered on a series of video games, originally developed by Midway Games in 1992. The development of the first game was originally based on an idea that Ed Boon and John Tobias had of making a video game starring Jean-Claude Van Damme, but as that idea fell through, a fantasy-themed fighting game was created instead, nonetheless paying homage to him with nut-cracking movie star character Johnny Cage, whose initials and personal style echo Van Damme's. Mortal Kombat was the first ever fighting game to introduce a secret fighter, reached if the player fulfilled a set of requirements. The original game has spawned many sequels and spin-offs consisting of several action-adventure games, as well as a comic book series and a card game. Film producer Lawrence Kasanoff licensed the rights to the game in the early 1990s and produced the first hit movie ever made from a video game. Lawrence also produced the second movie, animated TV series, live-action TV series films, the first one million platinum-selling album and a live-action tour. Mortal Kombat has become the most successful fighting franchise in the history of video games and one of the highest-grossing media franchises of all time. The series has a reputation for high levels of graphic violence, including, most notably, its Fatalities (finishing moves allowing the player to finish off their defeated opponent). Controversies surrounding Mortal Kombat, in part, led to the creation of the ESRB video game rating system. Early games in this series were also noted for their realistic digitized sprites and an extensive use of palette swapping to create new characters. Following Midway's bankruptcy, the Mortal Kombat development team was acquired by Warner Bros. Entertainment and turned into NetherRealm Studios.
  • 5.7K
  • 19 Oct 2022
Topic Review
Danaus (Genus)
Danaus, commonly called tigers, milkweeds, monarchs, wanderers, and queens, is a genus of butterflies in the tiger butterfly tribe. They are found worldwide, including North America, South America, Africa, Asia, Indonesia and Australia . For other tigers see the genus, Parantica.
  • 985
  • 19 Oct 2022
Topic Review
Cladistics
Cladistics (/kləˈdɪstɪks/; from grc κλάδος (kládos) 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics (synapomorphies) that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms worms or fishes were used within a strict cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. Radiation results in the generation of new subclades by bifurcation, but in practice sexual hybridization may blur very closely related groupings. As a hypothesis, a clade can only be rejected if some groupings were explicitly excluded. It may then be found that the excluded group did actually descend from the last common ancestor of the group, and thus emerged within the group. ("Evolved from" is misleading, because in cladistics all descendants stay in the ancestral group). Upon finding that the group is paraphyletic this way, either such excluded groups should be granted to the clade, or the group should be abolished. Testifying to human focus, bias and perhaps exceptionalism, humans have never been placed in a paraphyletic group, whereas most other organisms have been. Branches down to the divergence to the next significant (e.g. extant) sister are considered stem-groupings of the clade, but in principle each level stands on its own, to be assigned a unique name. For a fully bifurcated tree, adding a group to a tree also adds an additional (named) clade, and potentially a new level. Specifically, also extinct groups are always put on a side-branch, not distinguishing whether an actual ancestor of other groupings was found. The techniques and nomenclature of cladistics have been applied to disciplines other than biology. (See phylogenetic nomenclature.) Cladistics findings are posing a difficulty for taxonomy, where the rank and (genus-)naming of established groupings may turn out to be inconsistent. Cladistics is now the most commonly used method to classify organisms.
  • 3.2K
  • 19 Oct 2022
Topic Review
Schlüsselgerät 39
The Schlüsselgerät 39 (SG-39) was an electrically operated rotor cipher machine, invented by the German Fritz Menzer during World War II. The device was the evolution of the Enigma rotors coupled with three Hagelin pin wheels to provide variable stepping of the rotors. All three wheels stepped once with each encipherment. Rotors stepped according to normal Enigma rules, except that an active pin at the reading station for a pin wheel prevented the coupled rotor from stepping. The cycle for a normal Enigma was 17,576 characters. When the Schlüsselgerät 39 was correctly configured, its cycle length was [math]\displaystyle{ 2.7 x 10^8 }[/math] characters, which was more than 15,000 times longer than a standard Enigma. The Schlüsselgerät 39 was fully automatic, in that when a key was pressed, the plain and cipher letters were printed on separate paper tapes, divided into five-digit groups. The Schlüsselgerät 39 was abandoned by German forces in favour of the Schlüsselgerät 41.
  • 531
  • 19 Oct 2022
Topic Review
Outrigger Canoe
The outrigger canoe is a type of canoe featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull. Smaller canoes often employ a single outrigger on the port side, while larger canoes may employ a single-outrigger, double-outrigger, or double-hull configuration (see also catamaran). The sailing canoes are an important part of the Austronesian heritage. They are also very popular in Puerto Rico. Unlike a single-hulled canoe, an outrigger or double-hull canoe generates stability as a result of the distance between its hulls rather than due to the shape of each individual hull. As such, the hulls of outrigger or double-hull canoes are typically longer, narrower and more hydrodynamically efficient than those of single-hull canoes. Compared to other types of canoes, outrigger canoes can be quite fast, yet are also capable of being paddled and sailed in rougher water. This paddling technique, however, differs greatly from kayaking or rowing. The paddle, or blade, used by the paddler is single sided, with either a straight or a double-bend shaft.
  • 8.8K
  • 19 Oct 2022
Topic Review
Noocracy
Noocracy (/noʊˈɒkrəsi, ˈnoʊ.əkrəsi/), or "aristocracy of the wise", as originally defined by Plato, is a system of governance where decision making is in the hands of philosophers, similar to his idea of philosopher kings. The idea was further expanded upon by geologist Vladimir Vernadsky, and philosophers (who attended Vernadsky's lectures) Pierre Teilhard de Chardin and Édouard Le Roy, and their concept of the noosphere.
  • 1.8K
  • 19 Oct 2022
Topic Review
Factitious Disorder
A factitious disorder is a condition in which a person, without a malingering motive, acts as if they have an illness by deliberately producing, feigning, or exaggerating symptoms, purely to attain (for themselves or for another) a patient's role. People with a factitious disorder may produce symptoms by contaminating urine samples, taking hallucinogens, injecting fecal material to produce abscesses, and similar behaviour. Factitious disorder imposed on self (also called Munchausen syndrome) was for some time the umbrella term for all such disorders. Factitious disorder imposed on another (also called Munchausen syndrome by proxy, Munchausen by proxy, or factitious disorder by proxy) is a condition in which a person deliberately produces, feigns, or exaggerates the symptoms of someone in their care. In either case, the perpetrator's motive is to perpetrate factitious disorders, either as a patient or by proxy as a caregiver, in order to attain (for themselves or for another) a patient's role. Malingering differs fundamentally from factitious disorders in that the malingerer simulates illness intending to obtain a material benefit or avoid an obligation or responsibility. Somatic symptom disorders, though also diagnoses of exclusion, are characterized by physical complaints that are not produced intentionally.
  • 966
  • 19 Oct 2022
  • Page
  • of
  • 863

Other Entry Collections

>>