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De Havilland
The de Havilland Aircraft Company Limited () was a British aviation manufacturer established in late 1920 by Geoffrey de Havilland at Stag Lane Aerodrome Edgware on the outskirts of north London. Operations were later moved to Hatfield in Hertfordshire. Known for its innovation, de Havilland was responsible for a number of important aircraft, including the Moth biplane which revolutionised aviation in the 1920s; the 1930s Fox Moth, a commercial light passenger aircraft; the wooden World War II Mosquito multirole aircraft; and the pioneering passenger jet airliner Comet. The de Havilland company became a member of the Hawker Siddeley group in 1960, but lost its separate identity in 1963. Later, Hawker Siddeley merged into what is eventually known today as BAE Systems, the British aerospace and defence business. The de Havilland name lives on in De Havilland Canada, which owns the rights to the name and the aircraft produced by de Havilland's former Canadian subsidiary, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Designated Hitter
The designated hitter (DH) is a baseball player who bats in place of another position player, most commonly the pitcher. The position is authorized by Major League Baseball Rule 5.11. It was adopted by the American League in 1973 and later by the National League in 2022, making it universal in MLB. Within that time frame, nearly all amateur, collegiate, and professional leagues worldwide have adopted the designated hitter or some variant, with the notable exception of Nippon Professional Baseball's Central League. Major League Baseball rule In Major League Baseball, the designated hitter is a player who does not play a position in the field, but instead replaces the pitcher in the batting order. The DH may only be used for the pitcher (and not any other position player), as stated in Rule 5.11. Use of the DH is optional, but must be determined before the start of the game. Prior to 2022, if a team did not begin a game with a DH, the pitcher (or a pinch hitter) had to bat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doubled Haploidy
A doubled haploid (DH) is a genotype formed when haploid cells undergo chromosome doubling. Artificial production of doubled haploids is important in plant breeding. Haploid cells are produced from pollen or egg cells or from other cells of the gametophyte, then by induced or spontaneous chromosome doubling, a doubled haploid cell is produced, which can be grown into a doubled haploid plant. If the original plant was diploid, the haploid cells are monoploid, and the term doubled monoploid may be used for the doubled haploids. Haploid organisms derived from tetraploids or hexaploids are sometimes called dihaploids (and the doubled dihaploids are, respectively, tetraploid or hexaploid). Conventional inbreeding procedures take six generations to achieve approximately complete homozygosity, whereas doubled haploidy achieves it in one generation. Dihaploid plants derived from tetraploid crop plants may be important for breeding programs that involve diploid wild relatives of the cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Department Of Health (United Kingdom)
The Department of Health and Social Care (DHSC) is a department of His Majesty's Government responsible for government policy on health and adult social care matters in England, along with a few elements of the same matters which are not otherwise devolved to the Scottish Government, Welsh Government or Northern Ireland Executive. It oversees the English National Health Service (NHS). The department is led by the secretary of state for health and social care with three ministers of state and three parliamentary under-secretaries of state. The department develops policies and guidelines to improve the quality of care and to meet patient expectations. It carries out some of its work through arms-length bodies (ALBs), including executive non-departmental public bodies such as NHS England and the NHS Digital, and executive agencies such as the UK Health Security Agency and the Medicines and Healthcare products Regulatory Agency (MHRA). The DHSC also manages the work of the Nation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
District Heating
District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or biomass, but heat-only boiler stations, geothermal heating, heat pumps and central solar heating are also used, as well as heat waste from factories and nuclear power electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH) is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants. Fifth-generation district heat networks do not use combustion on-site and have zero emissions of CO and NO on-site; they employ heat t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermatitis Herpetiformis
Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a cutaneous manifestation of coeliac disease, although the exact causal mechanism is not known. DH is neither related to nor caused by herpes virus; the name means that it is a skin inflammation having an appearance (Latin: '' -formis'') similar to herpes. The age of onset is usually about 15–40, but DH also may affect children and the elderly. Men are slightly more affected than women. Estimates of DH prevalence vary from 1 in 400 to 1 in 10,000. It is most common in patients of northern European and northern Indian ancestry, and is associated with the human leukocyte antigen (HLA) haplotype HLA-DQ2 or HLA-DQ8 along with coeliac disease and gluten sensitivity. Dermatitis herpetiformis was first described by Louis Adolphus Duhring in 1884. A connection between DH and coeliac disease was recognized in 1967. Signs and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denavit–Hartenberg Parameters
In mechanical engineering, the Denavit–Hartenberg parameters (also called DH parameters) are the four parameters associated with a particular convention for attaching reference frames to the links of a spatial kinematic chain, or robot manipulator. Jacques Denavit and Richard Hartenberg introduced this convention in 1955 in order to standardize the coordinate frames for spatial linkages. Richard Paul demonstrated its value for the kinematic analysis of robotic systems in 1981. While many conventions for attaching reference frames have been developed, the Denavit–Hartenberg convention remains a popular approach. Denavit–Hartenberg convention A commonly used convention for selecting frames of reference in robotics applications is the Denavit and Hartenberg (D–H) convention which was introduced by Jacques Denavit and Richard S. Hartenberg. In this convention, coordinate frames are attached to the joints between two links such that one transformation is associated wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Humanities
Digital humanities (DH) is an area of scholarly activity at the intersection of computing or digital technologies and the disciplines of the humanities. It includes the systematic use of digital resources in the humanities, as well as the analysis of their application. DH can be defined as new ways of doing scholarship that involve collaborative, transdisciplinary, and computationally engaged research, teaching, and publishing. It brings digital tools and methods to the study of the humanities with the recognition that the printed word is no longer the main medium for knowledge production and distribution. By producing and using new applications and techniques, DH makes new kinds of teaching possible, while at the same time studying and critiquing how these impact cultural heritage and digital culture. DH is also applied in research. Thus, a distinctive feature of DH is its cultivation of a two-way relationship between the humanities and the digital: the field both employs tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DH Postcode Area
The DH postcode area, also known as the Durham postcode area,Royal Mail, ''Address Management Guide'', (2004) is a group of eight postcode districts in north-east England, which are subdivisions of five post towns. These districts cover northern County Durham (including Durham, Chester-le-Street, Consett and Stanley) and south-west Tyne and Wear (including Houghton-le-Spring), plus a very small part of Northumberland. __TOC__ Coverage The approximate coverage of the postcode districts: , - ! DH1 , DURHAM , Durham , County Durham , - ! DH2 , CHESTER LE STREET , Chester-Le-Street (west of East Coast Main Line), Ouston, Pelton, Birtley (west of East Coast Main Line) , County Durham, Gateshead , - ! DH3 , CHESTER LE STREET , Chester-le-Street (east of East Coast Main Line), Great Lumley, Birtley (east of East Coast Main Line) , County Durham, Gateshead , - ! DH4 , HOUGHTON LE SPRING , Houghton-le-Spring (West of A690), Penshaw, Shiney Row , County Durham, Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downhill Mountain Biking
Downhill mountain biking (DH) is a style of mountain biking practiced on steep, rough terrain that often features jumps, drops, rock gardens and other obstacles. Jumps can be up to and including , and drops can be greater than . The rider commonly travels to the point of descent a ski lift or automobile, since the weight of the downhill mountain bike often precludes any serious climbing. In this context, the use of a motorized vehicle or device does not make DH a motorized sport. Riders must possess a unique combination of total body strength, aerobic and anaerobic fitness, and the acceptance of a relatively high risk of incurring serious permanent injuries. Downhill bikes are heavier and stronger than other mountain bikes and feature front and rear suspension with over 8 inches (20 cm) of travel, to glide quickly over rocks and tree roots. In competitive races, a continuous course is defined on each side by a strip of tape. Depending on the format, riders h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decision Height
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landing, or to a point from which a landing may be made visually. These approaches are approved in the European Union by EASA and the respective country authorities and in the United States by the FAA or the United States Department of Defense for the military. The ICAO defines an instrument approach as, "a series of predetermined maneuvers by reference to flight instruments with specific protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if landing is not completed, to a position at which holding or enroute obstacle clearance criteria apply." There are three categories of instrument approach procedures: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delaware And Hudson Railway
The Delaware and Hudson Railway (D&H) is a railroad that operates in the Northeastern United States. In 1991, after more than 150 years as an independent railroad, the D&H was purchased by the Canadian Pacific Railway (CP). CP operates D&H under its subsidiary Soo Line Corporation which also operates Soo Line Railroad. D&H's name originates from the 1823 New York state corporation charter listing "The President, Managers and Company of the Delaware & Hudson Canal Co." authorizing an establishment of "water communication" between the Delaware River and the Hudson River. Nicknamed "The Bridge Line to New England and Canada," D&H connected New York with Montreal, Quebec and New England. D&H has also been known as "North America's oldest continually operated transportation company." On September 19, 2015, the Norfolk Southern Railway completed acquisition of the D&H South Line from CP. The D&H South Line is 282 miles (454 kilometers) long and connects Schenectady, New Yo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
