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C.H. Todd
CH, Ch, cH, or ch may refer to: Arts and entertainment * Television channel (sometimes abbreviated as "ch." for television and cable stations) * '' Chaos;Head'', a video game * '' Clone Hero'', a clone game version of popular rhythm game series '' Guitar Hero''. * CollegeHumor, a comedy website * E!, a defunct Canadian television system that went by the name CH from 2001 to 2007 Businesses * Bemidji Airlines (IATA code CH) * Carolina Herrera, a fashion designer based in New York * Columbia Helicopters, an aircraft manufacturing and operator company based in Aurora, Oregon, United States In language * Ch (digraph), considered a single letter in several Latin-alphabet languages * Chamorro language: ISO 639 alpha-2 language code (ch) Science and technology Chemistry * The methylidyne radical (a carbyne); CH• (or •CH), CH3• (or ⫶CH) * The methylidyne group ≡CH * The methine group (methanylylidene, methylylidene) =CH− Mathematics and computing * Chomsky hier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Channel
A television channel is a terrestrial frequency or virtual number over which a television station or television network is distributed. For example, in North America, "channel 2" refers to the terrestrial or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio ( FM), or 55.31 MHz for digital ATSC (8VSB). Channels may be shared by many different television stations or cable-distributed channels depending on the location and service provider Depending on the multinational bandplan for a given regional n, analog television channels are typically 6, 7, or 8 MHz in bandwidth, and therefore television channel frequencies vary as well. Channel numbering is also different. Digital terrestrial television channels are the same as their analog predecessors for legacy reasons, however through multiplexing, each physical radio frequency (RF) channel can carry several digital subchannels. On sat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curry–Howard Correspondence
In programming language theory and proof theory, the Curry–Howard correspondence (also known as the Curry–Howard isomorphism or equivalence, or the proofs-as-programs and propositions- or formulae-as-types interpretation) is the direct relationship between computer programs and mathematical proofs. It is a generalization of a syntactic analogy between systems of formal logic and computational calculi that was first discovered by the American mathematician Haskell Curry and the logician William Alvin Howard. It is the link between logic and computation that is usually attributed to Curry and Howard, although the idea is related to the operational interpretation of intuitionistic logic given in various formulations by L. E. J. Brouwer, Arend Heyting and Andrey Kolmogorov (see Brouwer–Heyting–Kolmogorov interpretation) and Stephen Kleene (see Realizability). The relationship has been extended to include category theory as the three-way Curry–Howard–Lambek correspondence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heavy Cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 inches) in caliber, whose design parameters were dictated by the Washington Naval Treaty of 1922 and the London Naval Treaty of 1930. The heavy cruiser is part of a lineage of ship design from 1915 through the early 1950s, although the term "heavy cruiser" only came into formal use in 1930. The heavy cruiser's immediate precursors were the light cruiser designs of the 1900s and 1910s, rather than the armored cruisers of the years before 1905. When the armored cruiser was supplanted by the battlecruiser, an intermediate ship type between this and the light cruiser was found to be needed—one larger and more powerful than the light cruisers of a potential enemy but not as large and expensive as the battlecruiser so as to be built in sufficient numbers to protect merchant ships and serve in a number of combat theaters. Wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Home
Chain Home, or CH for short, was the codename for the ring of coastal Early Warning radar stations built by the Royal Air Force (RAF) before and during the Second World War to detect and track aircraft. Initially known as RDF, and given the official name Air Ministry Experimental Station Type 1 (AMES Type 1) in 1940, the radar units themselves were also known as Chain Home for most of their life. Chain Home was the first early warning radar network in the world, and the first military radar system to reach operational status. Its effect on the outcome of the war made it one of the most powerful weapons of what is today known as the "Wizard War". In late 1934, the Tizard Committee asked radio expert Robert Watson-Watt to comment on the repeated claims of radio death rays and reports suggesting Germany had built some sort of radio weapon. His assistant, Arnold Wilkins, demonstrated that a death ray was impossible but suggested radio could be used for long-range detection. In Febr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cargo Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of STOL (Short TakeOff and Landing) or STOVL (Short TakeOff and Vertical Landing) aircraft cannot perform without a runway. In 1942, the Sikorsky R-4 became the first helicopter to reach full-scale production.Munson 1968.Hirschberg, Michael J. and David K. Dailey"Sikorsky". ''US and Russian Helicopter Development in the 20th Century'', American Helicopter Society, International. 7 July 2000. Although most earlier designs used more than one main rotor, the configuration of a single main rotor accompanied by a vertical anti-torque tail rotor (i.e. unicopter, not to be confused with the single-blade monocopter) has become the most common he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Catheter Scale
The French scale, French gauge or Charrière system is commonly used to measure the size of a catheter. It is most often abbreviated as Fr, but can often be seen abbreviated as Fg, FR or F. It may also be abbreviated as CH or Ch (for Charrière, its inventor). However, simply ''gauge'', ''G'' or ''GA'' generally refers to Birmingham gauge. The Charrière is measured by the ''outer'' diameter, and is defined as 1 Fr = 1/3 mm, and thus 1 mm = 3 Fr; therefore the diameter of a round catheter in millimetres can be determined by dividing the French size by 3., For example, if the French size is 9, the diameter is 9/3 = 3.0; mm. It is seen that the French unit is fully redundant with the metric system but introduces potential for rounding errors. This metrication problem is further complicated by the mixed use of metric and imperial units in medical professions using catheters. An increasing French size corresponds to a larger external diameter. This is contrary to Birmingham gauge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebellar Hypoplasia (non-human)
Cerebellar hypoplasia (CH) is a neurological condition in which the cerebellum is smaller than usual or not completely developed. It has been reported in many animal species. Function and development of the cerebellum The cerebellum is the brain's main control center for planning, adjusting, and executing movements of the body, the limbs and the eyes. It plays a major role in several forms of motor learning, including balance and posture. In the past, the evidence for a role for the cerebellum in cognitive functions was rather weak. However, investigations into the cognitive neuroscience of the cerebellum are rapidly advancing, extending far beyond the traditional view. For humans, current theories support that what the cerebellum does to sensorimotor and vestibular control, it also does to cognition, emotion, and autonomic function. How it functions in cognition, emotion, or autonomic function in animals is still largely unknown. In 2012, a study in mice provided dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebellar Hypoplasia
Cerebellar hypoplasia is characterized by reduced cerebellar volume, even though cerebellar shape is (near) normal. It consists of a heterogeneous group of disorders of cerebellar maldevelopment presenting as early-onset non–progressive congenital ataxia, hypotonia and motor learning disability. Various causes have been incriminated, including hereditary, metabolic, toxic and viral agents. It was first reported by French neurologist Octave Crouzon in 1929. In 1940, an unclaimed body came for dissection in London Hospital and was discovered to have no cerebellum. This unique case was appropriately named "human brain without a cerebellum" and was used every year in the Department of Anatomy at Cambridge University in a neuroscience course for medical students. Cerebellar hypoplasia can sometimes present alongside hypoplasia of the corpus callosum or pons. It can also be associated with hydrocephalus or an enlarged fourth ventricle; this is called Dandy–Walker malformation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Hypothyroidism
Congenital hypothyroidism (CH) is thyroid hormone deficiency present at birth. If untreated for several months after birth, severe congenital hypothyroidism can lead to growth failure and permanent intellectual disability. Infants born with congenital hypothyroidism may show no effects, or may display mild effects that often go unrecognized as a problem. Significant deficiency may cause excessive sleeping, reduced interest in nursing, poor muscle tone, low or hoarse cry, infrequent bowel movements, significant jaundice, and low body temperature. Causes of congenital hypothyroidism include iodine deficiency and a developmental defect in the thyroid gland, either due to a genetic defect or of unknown cause. Treatment consists of a daily dose of thyroid hormone (thyroxine) by mouth. Because the treatment is simple, effective, and inexpensive, most of the developed world utilizes newborn screening with blood thyroid stimulating hormone (TSH) levels to detect congenital hypothyr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesterol
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes. When chemically isolated, it is a yellowish crystalline solid. Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Cholesterol is the principal sterol synthesized by all animals. In vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as '' Mycoplasma'', which require cholesterol for growth. François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769. However, it was not until 1815 that chemist Michel Eugène Chevreul named the compound "cholesterine". Etymology The word "cholesterol" comes from the Ancient Greek ''chole-'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cluster Headache
Cluster headache (CH) is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye(s). There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affected side. These symptoms typically last 15 minutes to 3 hours. Attacks often occur in clusters which typically last for weeks or months and occasionally more than a year. The cause is unknown. Risk factors include a history of exposure to tobacco smoke and a family history of the condition. Exposures which may trigger attacks include alcohol, nitroglycerin, and histamine. They are a primary headache disorder of the trigeminal autonomic cephalalgias type. Diagnosis is based on symptoms. Recommended management includes lifestyle adaptations such as avoiding potential triggers. Treatments for acute attacks include oxygen or a fast-acting triptan. Measures recommended to decrease the frequency of attacks include steroid injections, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
