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Saab JAS 39 Gripen

The Saab JAS 39 Gripen is a light single-engine multirole fighter aircraft manufactured by the Swedish aerospace company Saab. It was designed to replace 37 Viggen in the Swedish Air Force; the Gripen has a delta wing and canard configuration with relaxed stability design and fly-by-wire flight controls. It is powered by the Volvo RM12, has a top speed of Mach 2. Aircraft are modified for NATO interoperability standards and to undertake air to air refuelling. In 1979, the Swedish government began development studies for an aircraft capable of fighter and reconnaissance missions to replace the Saab 35 Draken and 37 Viggen. A new design from Saab was selected and developed as the JAS 39, first flying in 1988. Following two crashes during flight development and subsequent alterations to the aircraft's flight control software, the Gripen entered service with the Swedish Air Force in 1996. Upgraded variants, featuring more advanced avionics and adaptations for longer mission times, began entering service in 2003.

To market the aircraft internationally, Saab formed partnerships and collaborative efforts with overseas aerospace companies. One example of such efforts was Gripen International, a joint partnership between Saab and BAE Systems formed in 2001. Gripen International was responsible for marketing the aircraft, was involved in the successful export of the type to South Africa. On the export market, the Gripen has achieved moderate success in sales to nations in Central Europe, South Africa and Southeast Asia. A further version, designated Gripen JAS 39E/F, is beginning deliveries to the Swedish and Brazilian air forces as of 2019; the changes include the adoption of a new powerplant, the General Electric F414G, an active electronically scanned array radar, increased internal fuel capacity. Saab has proposed other derivatives, including a navalised Gripen Maritime for carrier operations and an optionally manned aircraft for unmanned operations. Sweden and Brazil have ordered the Gripen E/F and Switzerland selected it for procurement.

As of January 2020, 306 Gripens have been built. In the late 1970s, Sweden sought to replace Saab 37 Viggen; the Swedish Air Force required an affordable Mach 2 aircraft with good short-field performance for a defensive dispersed basing plan in the event of invasion. One goal was for the aircraft to be smaller than the Viggen while equalling or improving on its payload-range characteristics. Early proposals included the Saab 38 called B3LA, intended as an attack aircraft and trainer, the A 20, a development of the Viggen that would have capabilities as a fighter and sea reconnaissance aircraft. Several foreign designs were studied, including the General Dynamics F-16 Fighting Falcon, the McDonnell Douglas F/A-18 Hornet, the Northrop F-20 Tigershark and the Dassault Mirage 2000; the Swedish government opted for a new fighter to be developed by Saab. In 1979, the government began a study calling for a versatile platform capable of "JAS", standing for Jakt and Spaning, indicating a multirole, or swingrole, fighter aircraft that can fulfill multiple roles during the same mission.

Several Saab designs were reviewed, the most promising being "Project 2105", recommended to the government by the Defence Materiel Administration. In 1980, Industrigruppen JAS was established as a joint venture by Saab-Scania, LM Ericsson, Svenska Radioaktiebolaget, Volvo Flygmotor and Försvarets Fabriksverk, the industrial arm of the Swedish armed forces; the preferred aircraft was a single-engine, lightweight single-seater, embracing fly-by-wire technology, an aerodynamically unstable design. The powerplant selected was the Volvo-Flygmotor RM12, a licence-built derivative of the General Electric F404−400. On 30 June 1982, with approval from the Riksdag, the FMV issued contracts worth SEK 25.7 billion to Saab, covering five prototypes and an initial batch of 30 production aircraft. By January 1983, a Viggen was converted to a flying test aircraft for the JAS 39's intended avionics, such as the fly-by-wire controls; the JAS 39 received the name Gripen via a public competition, the heraldry on Saab's logo.

Saab rolled out the first Gripen on 26 April 1987. Planned to fly in 1987, the first flight was delayed by 18 months due to issues with the flight control system. On 9 December 1988, the first prototype took its 51-minute maiden flight with pilot Stig Holmström at the controls. During the test programme, concern surfaced about the aircraft's avionics the fly-by-wire flight control system, the relaxed stability design. On 2 February 1989, this issue led to the crash of the prototype during an attempted landing at Linköping; the cause of the crash was identified as pilot-induced oscillation, caused by problems with the FCS's pitch-control routine. In response to the crash Saab and US firm Calspan introduced software modificatio

Nucleic acid quaternary structure

Nucleic acid quaternary structure refers to the interactions between separate nucleic acid molecules, or between nucleic acid molecules and proteins. The concept is analogous to protein quaternary structure, but as the analogy is not perfect, the term is used to refer to a number of different concepts in nucleic acids and is less encountered. Other biomolecules such as proteins, nucleic acids have four levels of structural arrangement: primary, secondary and quaternary structure. Primary structure is the linear sequence of nucleotides, secondary structure involves small local folding motifs, tertiary structure is the 3D folded shape of nucleic acid molecule. In general, quaternary structure refers to 3D interactions between multiple subunits. In the case of nucleic acids, quaternary structure refers to interactions between multiple nucleic acid molecules or between nucleic acids and proteins. Nucleic acid quaternary structure is important for understanding DNA, RNA, gene expression because quaternary structure can impact function.

For example, when DNA is packed into chromatin, therefore exhibiting a type of quaternary structure, gene transcription will be inhibited. DNA quaternary structure is used to refer to the binding of DNA to histones to form nucleosomes, their organisation into higher-order chromatin fibres; the quaternary structure of DNA affects how accessible the DNA sequence is to the transcription machinery for expression of genes. DNA quaternary structure varies over time, as regions of DNA are condensed or exposed for transcription; the term has been used to describe the hierarchical assembly of artificial nucleic acid building blocks used in DNA nanotechnology. The quaternary structure of DNA refers to the formation of chromatin; because the human genome is so large, DNA must be condensed into chromatin, which consists of repeating units known as nucleosomes. Nucleosomes contain; the nucleosome core contains around 146 DNA base pairs wrapped around a histone octamer. The histone octamer is made of eight total histone proteins, two of each of the following proteins: H2A, H2B, H3, H4.

Histones are responsible for shaping the nucleosomes, therefore drastically contributing to chromatin structure. Histone proteins are positively-charged and therefore can interact with the negatively-charged phosphate backbone of DNA. One portion of core histone proteins, known as histone tail domains, are important for keeping the nucleosome wrapped and giving the nucleosome secondary and tertiary structure; this is. The linker histone, or H1 protein, is involved maintaining nucleosome structure; the H1 protein has the special role of ensuring that DNA stays wound. Modifications to histone proteins and their DNA are classified as quaternary structure. Condensed chromatin, prevents transcription of genes. In other words, transcription factors cannot access wound DNA- This is in contrast to euchromatin, decondensed, therefore accessible to the transcriptional machinery. DNA methylation to nucleotides influences chromatin quaternary structure. Methylated DNA nucleotides are more found within heterochromatin whereas unmethylated DNA nucleotides are common in euchromatin.

Furthermore, post-translational modifications can be made to the core histone tail domains, which lead to changes in DNA quaternary structure and therefore gene expression. Enzymes, known as epigenetic writers and epigenetic erasers, catalyze either the addition or removal of several modifications to the histone tail domains. For instance, an enzyme writer can methylate Lysine-9 of the H3 core protein, found in the H3 histone tail domain; this can lead to gene repression as the chromatin resembles heterochromatin. However, dozens of modifications can be made to histone tail domains. Therefore, it is the sum of all those modifications that determine whether chromatin will resemble heterochromatin or euchromatin. RNA is subdivided into many categories, including messenger RNA, ribosomal RNA, transfer RNA, long non-coding RNA, several other small functional RNAs. Whereas many proteins have quaternary structure, the majority of RNA molecules have only primary through tertiary structure but function as individual molecules rather than as multi-subunit structures.

Some types of RNA show clear quaternary structure, essential for function, whereas other types of RNA function as single molecules and do not associate with other molecules to form quaternary structures. Symmetrical complexes of RNA molecules are uncommon compared to protein oligomers. One example of an RNA homodimer is the VS ribozyme from Neurospora, with its two active sites consisting of nucleotides from both monomers; the best known example of RNA forming quaternary structures with proteins is the ribosome, which consists of multiple rRNAs, supported by rProteins. Similar RNA-Protein complexes are found in the spliceosome. Riboswitches are a type of mRNA structure that help regulate gene expression and bind a diverse set of ligands. Riboswitches determine how gene expression responds to varying concentrations of small molecules in the cell This motif has been observed in flavin mononucleotide, cyclic di-AMP, glycine. Riboswitches are said to show pseudoquaternary structure. Several structurally similar regions of a single RNA molecule fold together symmetrically.

Because this structure arises from a single molecule and not from multiple separate molecules, it cannot be referred to as true quaternary structure. Depending on where a riboswitch binds and how it is arranged, it can suppr

Sia (title)

Sia was a hereditary title of Chinese origin, used in colonial Indonesia. It was borne by the descendants of Chinese officers, who were high-ranking, Chinese civil bureaucrats in the Dutch colonial government, bearing the ranks of Majoor, Kapitein or Luitenant der Chinezen; as with other Chinese honorifics, the title'Sia' came at the end of the title holder's name: for example, as in Oey Tamba Sia. The title was used not with its holder's surname, but with his given name, so Tamba Sia instead of Oey Sia. In everyday speech, use of the title was combined with other honorifics, such as Ako Sia or Baba Sia; the honorific was used in Imperial China to address certain senior mandarins, the relatives of a mandarin or descendants of the House of Koxinga the ruling dynasty of the Kingdom of Tungning. In colonial Indonesia, the honorific came to be used as a hereditary title for the descendants of Chinese officers, who were seen as the colonial Indonesian equivalent of the Chinese mandarinate and scholar-gentry.

These title holders and their families constituted the so-called Cabang Atas, the traditional Chinese establishment or gentry of colonial Indonesia. As a class, they dominated the administrative posts of Majoor and Luitenant der Chinezen, or the Chinese officership on a near-hereditary basis. To a significant extent, they monopolised the colonial government's lucrative revenue farms, which formed the economic backbone of their political influence. To preserve and consolidate their power, families of the Cabang Atas contracted extensive, strategic intermarriages within their social group. In the colonial period, it became fashionable among western-educated title holders to refrain from using the title'Sia', seen as an old-fashioned anachronism; this mirrored the decline in the importance of the Chinese officership as a government institution in the early twentieth century, which presaged its eventual abolition in most of the Dutch East Indies with the exception of the colonial capital, Batavia.

Indeed, as pointed out by Monique Erkelens, the prestige of the traditional elite declined in the early twentieth century due to changing political and ideological circumstances in late colonial Indonesia and early twentieth-century Asia. As part of the Cabang Atas, Sias played an important role in the history of Indonesia in relation to the country's ethnic Chinese community. Prominent Sias include: Han Chan Piet, Majoor der Chinezen: government official and landlord Han Kik Ko, Majoor der Chinezen, Regent of Probolinggo: government official and landlord Lim Ke Tjang, Kapitein der Chinezen of Tegal: official and sugar magnate Tan Eng Goan, 1st Majoor der Chinezen of Batavia Oey Tamba Sia: notorious Batavia playboy Lie Tjoe Hong, 3rd Majoor der Chinezen of Batavia Phoa Keng Hek Sia: social reformer and philanthropist O. G. Khouw: philanthropist Khouw Kim An, last Majoor der Chinezen of Batavia: government bureaucrat H. H. Kan: politician, parliamentarian Loa Sek Hie: politician, social worker Phoa Liong Gie: newspaper publisher, parliamentarian Kapitan Cina Cabang Atas Scholar-gentry and landed gentry in China Chinese honorifics The House of Koxinga

Stamford, Lincolnshire

Stamford is a town on the River Welland in Lincolnshire, England, 92 miles north of London on the A1. The population at the 2011 census was 19,701; the town has 17th and 18th-century stone buildings, older timber-framed buildings and five medieval parish churches. Stamford is a frequent filming location. In 2013 it was rated the best place to live in a survey by The Sunday Times; the Romans built Ermine Street across what is now Burghley Park and forded the river Welland to the west of Stamford reaching Lincoln. In AD 61 Boudica followed the Roman legion Legio IX Hispana across the river; the Anglo-Saxons chose Stamford as their main town, being on a more important river than the Gwash. The place-name Stamford is first attested in the Anglo-Saxon Chronicle, where it appears as Steanford in 922 and Stanford in 942, it appears as Stanford in the Domesday Book of 1086. The name means "stony ford". In 972 King Edgar made Stamford a borough; the Anglo-Saxons and Danes faced each other across the river.

The town had grown as a Danish settlement at the lowest point that the Welland could be crossed by ford or bridge. Stamford was the only one of the Five Boroughs of the Danelaw not to become a county town. A pottery centre making Stamford Ware, by the Middle Ages it had gained fame for its production of wool and the woollen cloth known as Stamford cloth or haberget – which "In Henry III's reign... was well known in Venice."Stamford was a walled town, but only a small portion of the walls remains. Stamford became an inland port on the Great North Road, the latter superseding Ermine Street in importance. Notable buildings in the town include the medieval Browne's Hospital, several churches and the buildings of Stamford School, a public school founded in 1532. A Norman castle was built about 1075 and demolished in 1484; the site stood derelict until the late 20th century, when it was built over and now includes a bus station and a modern housing development. A small part of the curtain wall survives at the junction of Bath Row.

Stamford has been hosting an annual fair since the Middle Ages. Stamford fair is mentioned in Shakespeare's Henry IV, Part 2; the mid-Lent fair is the largest street fair in one of the largest in the country. On 7 March 1190, crusaders at the fair led a pogrom. For over 600 years Stamford was the site of the Stamford Bull Run, a festival held annually on 13 November, St Brice's day, until 1839. According to local tradition, this was started by William de Warenne, 5th Earl of Surrey, after seeing two bulls fighting in the meadow beneath his castle; some butchers came to part the combatants and one of the bulls ran into the town. The earl rode after the animal; the East Coast Main Line was planned to go through Stamford, as an important postal town at the time, but resistance there led to routing it instead through Peterborough, whose importance and size increased at Stamford's expense. Stamford Museum occupied a Victorian building in Broad Street from 1980 to 2011. In June 2011 it was closed by Lincolnshire County Council budget cuts.

Some exhibits have been relocated to the Discover Stamford area at the town's library and to the Town Hall. Stamford belongs to the Parliamentary constituency of Stamford; the incumbent Member is Gareth Davies of the Conservative Party, who won the seat at the 2019 General Election. His predecessor, Nick Boles, had since March 2019 been an Independent, though stating he was still conservative in outlook and calling himself an "Independent Progressive Conservative". In local government, Stamford since April 1974 has been in the areas of Lincolnshire County and South Kesteven District Council, it belonged to Kesteven County Council. Stamford's town council has arms: Per pale dexter side Gules three Lions passant guardant in pale Or and the sinister side chequy Or and Azure; the three lions are the English royal arms, granted to the town by Edward IV for its part in the "Lincolnshire Uprising". The blue and gold chequers are the arms of the De Warenne family, which held the Manor in the 13th century.

Stamford, as a town and civil parish in the South Kesteven district of Lincolnshire, on the River Welland, forms a south-westerly protrusion of Lincolnshire between Rutland to the north and west, Peterborough to the south, Northamptonshire to the south-west. There have been mistaken claims of a quadripoint where four ceremonial counties, Lincolnshire and Northamptonshire would meet at a point, but the location has two tripoints some 66 ft apart. In 1991, the boundary between Lincolnshire and Rutland in the Stamford area was redrawn, it now follows the A1 to the railway line. The conjoined parish of Wothorpe is in the city of Peterborough. Barnack Road is the Lincolnshire/Peterborough boundary; the river downstream of the town bridge and some of the meadows fall within the drainage area of the Welland and Deepings Internal Drainage Board. Much of Stamford is built with mudstones and sandstones. In 1968, a specimen of the sauropod dinosaur Cetiosaurus oxoniensis was found in the Williamson Cliffe Quarry, close to Great Casterton in adjacent Rutland.

Some 15 metres long, it is about 170 million years old, from the Aalenian or Bajocian era of the Jurassic period, It is of the most complete dinosaur skeletons found i

Irina Gordeeva

Irina Andreyevna Gordeeva is a Russian high jumper. She finished seventh at the 2003 World Youth Championships, ninth at the 2004 World Junior Championships, fifth at the 2009 European Indoor Championships and fifth at the 2009 World Athletics Final, she competed at the 2010 World Indoor Championships without reaching the final. Her personal best is 2,04 metres, achieved in August 2012 in Eberstadt, it is 5th result among Russian high jumpers after Anna Chicherova, Mariya Lasitskene, Elena Slesarenko and Tamara Bykova. Gordeeva won a bronze medal at the 2012 European Athletics Championships in Helsinki on 28 June

Clarence Clark (golfer)

Clarence E. Clark was an American professional golfer. Clark worked as a golf pro at McFarlin Golf Club, Forest Hill Field Club, Carey Park Golf Course, O'Brien's Golf Center, Newton Country Club, Dyess Air Force Base Golf Course and Lazee Tee Golf Center, he played on the PGA Tour, winning seven times in the 1930s, including the Texas Open and Houston Open on consecutive weeks in 1932. In 1936, he was tied for the lead in the U. S. finished the tournament tied for third. Clark died in Abilene, Texas in 1974. 1931 Central Florida Open, New Jersey PGA Championship 1932 Texas Open, Houston Open 1933 New Jersey Open 1934 Hazard Kentucky Open 1936 Lake Placid Open 1930 Oklahoma Open Note: Clark never played in The Open Championship. NYF = tournament not yet founded CUT = missed the half-way cut "T" indicates a tie for a place R64, R32, R16, QF, SF = round in which player lost in PGA Championship match play List of golfers with most PGA Tour wins