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Production of antibiotics

Production of antibiotics is a naturally occurring event, that thanks to advances in science can now be replicated and improved upon in laboratory settings. Due to the discovery of penicillin by Alexander Fleming, and the efforts of Florey and Chain in 1938, large-scale, pharmaceutical production of antibiotics has been made possible. As with the initial discovery of penicillin, most antibiotics have been discovered as a result of happenstance. Antibiotic production can be grouped into three methods: natural fermentation, semi-synthetic, and synthetic. As more and more bacteria continue to develop resistance to currently produced antibiotics, research and development of new antibiotics continues to be important. In addition to research and development into the production of new antibiotics, repackaging delivery systems is important to improving efficacy of the antibiotics that are currently produced. Improvements to this field have seen the ability to add antibiotics directly into implanted devices, aerosolization of antibiotics for direct delivery, and combination of antibiotics with non antibiotics to improve outcomes. The increase of antibiotic resistant strains of pathogenic bacteria has led to an increased urgency for the funding of research and development of antibiotics and a desire for production of new and better acting antibiotics.

Identifying useful antibiotics
Despite the wide variety of known antibiotics, less than 1% of antimicrobial agents have medical or commercial value. For example, whereas penicillin has a high therapeutic index as it does not generally affect human cells, this is not so for many antibiotics. Other antibiotics simply lack advantage over those already in use, or have no other practical applications.

Useful antibiotics are often discovered using a screening process. To conduct such a screen, isolates of many different microorganisms are cultured and then tested for production of diffusible products that inhibit the growth of test organisms. Most antibiotics identified in such a screen are already known and must therefore be disregarded. The remainder must be tested for their selective toxicities and therapeutic activities, and the best candidates can be examined and possibly modified.

A more modern version of this approach is a rational design program. This involves screening directed towards finding new natural products that inhibit a specific target, such as an enzyme only found in the target pathogen, rather than tests to show general inhibition of a culture.

Research into antibiotic identification has shown the opportunity exists to move away from lawn spotting methodology, a methodology which increases the chances of cross contamination. This new methodology involves using Lactobacillus species and shows a clear zone of inhibition as well as allowing for a determination of minimum inhibitory concentration.

Fermentation
Industrial microbiology can be used to produce antibiotics via the process of fermentation, where the source microorganism is grown in large containers (100,000–150,000 liters or more) containing a liquid growth medium. Oxygen concentration, temperature, pH and nutrient are closely controlled. As antibiotics are secondary metabolites, the population size must be controlled very carefully to ensure that maximum yield is obtained before the cells die. Once the process is complete, the antibiotic must be extracted and purified to a crystalline product. This is easier to achieve if the antibiotic is soluble in organic solvent. Otherwise it must first be removed by ion exchange, adsorption or chemical precipitation.

Semi-synthetic
A common form of antibiotic production in modern times is semi-synthetic. Semi-synthetic production of antibiotics is a combination of natural fermentation and laboratory work to maximize the antibiotic. Maximization can occur through efficacy of the drug itself, amount of antibiotics produced, and potency of the antibiotic being produced. Depending on the drug being produced and the ultimate usage of said antibiotic determines what one is attempting to produce.

An example of semi-synthetic production involves the drug ampicillin. A beta lactam antibiotic just like penicillin, ampicillin was developed by adding an addition amino group (NH2) to the R group of penicillin. This additional amino group gives ampicillin a broader spectrum of use than penicillin. Methicillin is another derivative of penicillin and was discovered in the late 1950s, the key difference between penicillin and methicillin being the addition of two methoxy groups to the phenyl group. These methoxy groups allow methicillin to be used against penicillinase producing bacteria that would otherwise be resistant to penicillin.

Synthetic
Not all antibiotics are produced by bacteria; some are made completely synthetically in the lab. These include the quinolone class, of which nalidixic acid is often credited as the first to be discovered. Like other antibiotics before it the discovery of nalidixic acid has been chalked up to an accident, discovered when George Lesher was attempting to synthesize chloroquine. However a recent investigation into the origin of quinolones have discovered that a description for quinolones happened in 1949 and that patents were filed concerning quinolones some 5 years before Lesher's discovery.

Strains used for the production
In the earliest years of antibiotic discovery the antibiotics being discovered were naturally produced antibiotics and were either produced by fungi, such as the antibiotic penicillin, or by soil bacteria, which can produce antibiotics including streptomycin and tetracycline.

Microorganisms used in fermentation are rarely identical to the wild type. This is because species are often genetically modified to yield the maximum amounts of antibiotics. Mutation is often used, and is encouraged by introducing mutagens such as ultraviolet radiation, x-rays or certain chemicals. Selection and further reproduction of the higher yielding strains over many generations can raise yields by 20-fold or more. Another technique used to increase yields is gene amplification, where copies of genes coding for enzymes involved in the antibiotic production can be inserted back into a cell, via vectors such as plasmids. This process must be closely linked with retesting of antibiotic production.

Some antibiotics are produced naturally by fungi. These include the cephalosporin producing Acremonium chrysogenum.

Geldanamycin is produced by Streptomyces hygroscopicus.

Erythromycin is produced by what was called Streptomyces erythreus and is now known as Saccharopolyspora erythraea.

Streptomycin is produced by Streptomyces griseus.

Tetracycline is produced by Streptomyces aureofaciens

Vancomycin is produced by Streptomyces orientalis, now known as Amycolatopsis orientalis.

Advancements
Penicillin was the first of the antibiotics to be discovered. After the discovery there was the issue of taking the raw naturally produced penicillin and developing a method so that wide-scale production of a clinically significant antibiotic could occur. Over the course of many years a team led by Florey and Chain and based in Oxford was able to successfully purify, concentrate, and produce the antibiotic.

Advances in scientific technology have not always led to better conditions for the production of antibiotics. Since 1987 there have been no new classes of antibiotics discovered for industrial production and widespread usage. However new developments in genomic sequencing and technology have led to improvements and discovery in the field of antibiotic production. Genomic engineering of antibiotic gene clusters has already been shown to lead to an increase in production of different antibiotics.

Antibiotic production and delivery method
Antibiotics do not render themselves fully functional and deliverable simply by being produced. Often modifications must be made to the antibiotics so that maximum efficiency is attained. Post-production modifications include making antibiotics aerosolized so as to bypass doing unnecessary damage to bacteria located in other parts of the body and instead going directly to the lungs. Nosocomial infections can lead to serious complications during and in the recovery following surgery or a hospital stay in general. By merging surgical implants with antibiotics, healthcare providers are able to strike at a specific high risk area of infection without having to use a body wide size dosage of antibiotics.

Meropenem is an antibiotic that is delivered into the body via injection. When produced meropenem is a crystalline antibiotic, so it must be mixed in with solution before injection can occur. During this process meropenem is mixed with sodium carbonate, then diluted in water after which it can be injected.

Aerosolization of antibiotics is necessary because infections of the lung are especially troublesome, which is why direct targeting of the infection is needed. Broad spectrum antibiotics can have detrimental side effects when their action is also taken against necessary non-pathogenic bacteria residing in the human microbiome. Aerosolization is effective in bypassing the microbiome that exists in the gastrointestinal tract by directing the antibiotic directly to the lungs. This process is undertaken after the production of the antibiotic itself.

The rise of antibiotic-resistant bacteria has affected implantation of medical devices. In some cases it is no longer enough for devices to be sterile when they are implanted into an individual, now they must be proactive in fighting off bacterial infection. As such antibiotics are now being added into the surface of implanted devices as an added layer of defense against the threat of infection. One such infection is Osteomyelitis which can offer a unique challenges in treatment efforts, one novel approach has been the creation of antibiotic cement nails which can be inserted into the infected bone. First described by Paley and Herzenberg antibiotic cement nails have dual purpose, both of stabilization of the bone being treated, and prevention against post-procedure infection. Antibiotic cement nails are inserted during surgery, and are produced around the time of procedure using materials available in the operating room setting. Antibiotics are mixed in with cement filling then molded around a support anchor, often chest tubes are used to ensure proper molding. Chest tubes have the advantage of being cheap and ubiquitous and have been shown to have uniformity in the production of antibiotic cement nails. The antibiotics fill the voids within the cement matrix, and upon drying and setting can be inserted into the bone. The antibiotic has a direct contact with the area of infection and retains its properties in acting upon the infection. In addition to cement nails, antibiotic cement spacers have been used to treat and prevent osteomyelitis, and for a longer period of time. In producing the antibiotic cement material it is necessary to choose antibiotics that will be effective in this hybrid form, it has been found that antibiotics in powder form that are broad spectrum are of best use. There are recommendations for the amount of antibiotic that is used when mixing in with the cement, but industry wide guidelines have not been established.

Challenges
Development of antibiotics is difficult, whereas many drug discoveries have been a result of concerted effort and intensive research and development, antibiotics have seemingly been discovered by chance. Since 1987 there have been no discoveries or development of a new class of antibiotics. This is partly due to the finicky nature of antibiotics. As most are produced biosynthetically they require an organism to produce. Historically this has meant that different species are grown and observed for any antimicrobial activity. Not only does this require a culturable species to start off with, but the conditions the species are grown in must be adequate for production of antibiotics as well as having the number of antibiotics produced reach a density threshold so that their function can be observed.

Another reason behind the lack of new antibiotic production is the diminishing amount of return on investment for antibiotics and thus the lack resources put into research and development by private pharmaceutical companies. The World Health Organization has recognized the danger of antibiotic resistance bacteria and has created a list of "priority pathogens" that are of the utmost concern. In doing so the hope is to stimulate R&D that can create a new generation of antibiotics. In the United States, the Biomedical Advanced Research and Development Authority (BARDA) aims to support the work of the industry to produce new antibiotics.

The buildup of inorganic phosphate can limit the biosynthetic production of certain antibiotics, researchers found that by using an inorganic phosphate trapping agent, the phosphate would be sequestered away and antibiotic production would return to normal levels, thus allowing production to continue.

Meropenem is mixed with sodium carbonate post-production before being injected into the body, subsequent analysis of this mixture using Nuclear Magnetic Resonance has shown that a second form of Meropenem is produced. This second form has an additional carbon dioxide on it, and exists alongside the pure form. In order to ensure that Meropenem stays in the correct form a four-step process was developed wherein the crude form is mixed together with a base in water, a proper pH is established, the product is treated with alkanols, and then the pure form is isolated.

title: Production of antibiotics


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Japan New Party

The Japan New Party (日本新党) was a Japanese political party that existed briefly from 1992 to 1994.

The party, considered liberal, was founded by Morihiro Hosokawa, a former Diet member and Kumamoto Prefecture governor, who left the Liberal Democratic Party to protest corruption scandals. In 1992, the party elected four members to the House of Councillors, including Hosokawa. Although this was a disappointing result for them, in 1993 they were able to capitalize on voter dissatisfaction with the LDP, electing a total of 35 members (including 3 who joined after the election). Hosokawa became Prime Minister leading a broad coalition, but was soon forced to resign.

The party defended the political reformism, rights of consumers and supported decentralization.

By 1994, the Japan New Party dissolved, its members flowing into the New Frontier Party (新進党).

Several Diet members who've become prominent in other parties were first elected for the Japan New Party, including Yoshihiko Noda, Seiji Maehara, Yukio Edano, Toshimitsu Motegi and Yuriko Koike.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Japan New Party


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Martin von Wahrendorff

Martin von Wahrendorff (1789 – 1861) was a Swedish diplomat and inventor.

His father Anders von Wahrendorff was the owner of the gun foundry at Åker. Wahrendorff was Grand Master of Ceremonies at the Royal Court of Sweden from 1828 to 1831

In 1837 Wahrendorff applied for patent on a new breech mechanism, later known as the Wahrendorff breech. The first breech loaded Wahrendorff gun was manufactured at Åker in 1840. In the 1840s the Sardinian major Giovanni Cavalli was sent to the Åker foundry to inspect guns that the Sardinian government had ordered. The two then started experimenting with pointed elongated lead-coated projectiles fired from rifled, breech loading, guns of Wahrendorff's design. In 1854 the Swedish Army adopted three different types of smooth bored breech loaded Wahrendorff guns, in calibers from 155 to 226 mm.

Wahrendorff died in 1861.

title: Martin von Wahrendorff


text: User talk:212.24.94.3

title: User talk:212.24.94.3


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User:That One Girl

I just joined because I like to research things in my spare time and this site seemed like a good idea. I'm all for free Internet.

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User talk:Timothypdevine

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Southwell, Nottinghamshire

Southwell  is a minster and market town, and a civil parish, in the district of Newark and Sherwood in Nottinghamshire, England. It is home to the grade-I listed Southwell Minster, the cathedral of the Anglican Diocese of Southwell and Nottingham. The population of the town was recorded at 7,491 in the 2021 census.

Toponymy
The origin of the name is unclear. Several sites claim to be the original "well", notably at GR where a plaque has been placed; in the Admiral Rodney pub; on the south side of the Minster, known as Lady Well in the 19th century; and one by the cloisters called Holy Well. Norwell, 8 mi northwest, may support the idea of a pair of "south" and "north" wells, although no wells are known to exist. There was a complex relationship with the two, Norwell being owned by and contributing to the Prebends of Southwell, the place name possibly given to help distinguish this.

In most of Nottinghamshire, Southwell is pronounced SUH-thull, with a voiced "th" and a silent "w". Southwell's own residents tend to pronounce it as it is spelt.

Early history
The remains of an opulent Roman villa were excavated beneath the Minster and its churchyard in 1959. Part of a mural from the excavation is displayed in the Minster. It is one of three of its type found in the territories of the Corieltauvi (or Coritani) tribes – along with Scampton in Lincolnshire and Norfolk Street in Leicestershire. A stretch of the Fosse Way runs on the far bank of the River Trent, with evidence of Roman settlement at Ad Pontem ("to the bridge" or "at the bridge"), northwest of the village of East Stoke. There is no clear evidence of a road between Ad Pontem and Southwell. Other evidence of Roman settlement includes the use of Roman bricks in prebendary buildings around the Minster, remains of a ditch or fosse discovered at Burgage Hill in the 19th century, and possibly Roman remains beneath the Church Street site of the recently vacated Minster School.

The Venerable Bede records a multiple baptism in the "flood of the Trent" near "Tiovulginacester" by Paulinus in the presence of Edwin of Northumbria, whom he had converted to Christianity in 627. There is disagreement on the location of Tiovulginacester, but Paulinus certainly visited it and may have founded the first church in Southwell.

Remains of Eadburh, Abbess of Repton and daughter of Ealdwulf of East Anglia were buried in Southwell's Saxon church. Eadburh was appointed Abbess under the patronage of King Wulfhere of Mercia. She appears in the Life of Guthlac and is thought to have died about AD 700. Her remains were buried or translated to Southwell Minster, and revered there in the Middle Ages. The only reference is in a Pilgrims Guide to Shrines and Burial Places of the Saints of England supposedly written in 1000: "There resteth St. Eadburh in the Minster of Southwell near the water called the Trent."

Eadwy of England gave land in Southwell to Oskytel, Archbishop of York, in 956, this charter being the first dated reference to Southwell. In 1051 Archbishop Ælfric Puttoc died at Southwell, which indicates that the archiepiscopal residence and church might have been established by then. A tessellated floor and the 11th-century tympanum over a doorway in the north transept are evidence of construction of the Minster after this time. The Domesday Book (1086) gives detail of an archiepiscopal manor in Southwell.

A custom known as the "Gate to Southwell" originated after 1109, when the Archbishop of York, Thomas I, wrote to each Nottinghamshire parish for contributions to building of a new mother church. Annually at Whitsuntide, the resulting "Southwell Pence" were taken to the Minster in a procession from Nottingham, headed by the Mayor and followed by clergy and lay people bound for Southwell's Whitsun Fair. The Pence were paid at the Minster's north porch to the Chapter Clerk. The "gate" in the name of Southwell Gate means "street", as in many East Midland and North-Eastern street names. The custom in its original form persisted well into the 16th century. It was revived in 1981 by the Dolphin Morrismen, but imposition of traffic-management costs forced the organisers to abandon it in 2014. It is survived by the Gate to Southwell Festival, a broad musical event held annually since 2007 (except 2020) now in early July on a site near Southwell and at various venues in the town.

Geoffrey Plantagenet was ordained a priest at Southwell in 1189. On 4 April 1194, Richard I and the King of Scots, William I, were in Southwell, having spent Palm Sunday in Clipstone. King John visited Southwell between 1207 and 1213, ostensibly to hunt in Sherwood Forest, but also on the way to expedition to Wales in 1212.

1300–1800
The Saracen's Head was built in 1463 on land gifted in 1396 by Archbishop Thomas Arundel of York to John and Margaret Fysher. When built, the first floor overhung the roadway in the style of the time.

In 1530, Cardinal Thomas Wolsey stayed at the archbishop's palace in Southwell for a few months. The Cardinal had been arrested after failing to secure an annulment between King Henry VIII and Catherine of Aragon. The Cardinal was ordered to London by Henry Percy, 6th Earl of Northumberland for treason and became ill along the way.

In 1603, King James VI of Scotland passed through Southwell on his way to London to be crowned King James I of England.

In the English Civil War, King Charles I spent his last night as a free man in May 1646 in the Saracen's Head (then the King's Head), before surrendering to the Scottish Army stationed at nearby Kelham. The town, the Minster and the Archbishop's Palace suffered under Oliver Cromwell's troops, as they sequestered the palace to stable their horses, broke monuments, and ransacked graves for lead and other valuables. In 1793, there were still iron rings in the walls to secure the horses. By end of the war the Archbishop's Palace was in ruins apart from its Great Hall. It is reputed that Cromwell also stayed at the King's Head.

A bridewell built on the Burgage in 1656 was enlarged in 1787 to become a county prison. There is evidence that a house of correction was built in 1611, so that the bridewell may itself have been an enlargement.

Mary Ann Brailsford of apple fame (see below) was baptised at Southwell in May 1791, and Matthew Bramley in 1796 in Balderton.

19th century and later
By 1801 the population was 2,305.

In 1803, Lord Byron stayed with his mother in Burgage Manor during holidays from Harrow and Cambridge. His mother rented the house. By that time he had become 6th Baron Byron of Rochdale, but the family home, Newstead Abbey, still required repairs, which they could not afford.

The Bramley cooking apple was first seeded in Southwell, by Mary Ann Brailsford in 1809. Henry Merryweather, a local nurseryman then 17 years old, saw potential and cultivated it from cuttings. The apple is widely used and renowned for its acidic taste and for cooking into a smooth purée. One local football club, Southwell City, is nicknamed "The Bramleys" and the town's library is called the Bramley Centre. In March 2009, a stained-glass window was placed in Southwell Minister to mark the apple's bicentenary.

The town was late in getting a permanent theatre. This was in the yard of the former Cross Keys. In 1816 two large rooms on the first floor of premises of James Adams, a whitesmith, were converted for use as a theatre. The first company to use it was that of Joseph Smedley.

The Diocese of Southwell was established in 1884, with Southwell Minster becoming its cathedral church. As established, the diocese included both Nottinghamshire and Derbyshire, but a new Diocese of Derby was formed in 1927 to encompass the part of the Diocese of Southwell in Derbyshire. In 2005 the diocese was renamed the Diocese of Southwell and Nottingham.

Location
The town is on the River Greet and is located 9 mi west of Newark on Trent, 15 mi northeast of Nottingham, 13 mi southeast of Mansfield and 22 mi southeast of Worksop.

Town districts
The historic town centre is based around the cathedral area, but nearby outlying communities grew and eventually were subsumed into the town.

 * The Prebendage was the heart of Southwell centred on the Minster and the surrounding prebendary properties
 * Burgage was north of the cathedral, around Burgage Green, traditionally hosting burgage properties
 * Hightown was to the northwest along Westgate, along the main shopping street
 * East Thorpe and West Thorpe were hamlets on either side of these areas, St Catherine's Well, at the extremity of West Thorpe, was formerly noted for treating rheumatism.

Localities
Separated further afield from the core urban area, but within the civil parish are the following places:

 * Normanton, a hamlet on the east side of the River Greet positioned around Corkhill Lane, it hosts a sizeable garden centre business
 * Maythorne, a hamlet around a listed former silk mill north of the town, alongside the River Greet
 * Brackenhurst, an agricultural campus for Nottingham Trent University, is to the south
 * Brinkley is a hamlet to the southeast along Fiskerton Road.

Economy
The town is something of an oddity in North Nottinghamshire, being visibly affluent compared with neighbouring Newark-on-Trent and Mansfield. Agriculture and coal have seen the fortunes of the other two fluctuate over the years, while Southwell has remained a place where wealthier Nottinghamians like to reside. It appeared in the Sunday Times shortlist of Best Places to Live 2017 for the Midlands region.

Government
As the site of an Anglican cathedral, the town is sometimes mistakenly described as a city, and indeed was treated as such in the 1911 Encyclopædia Britannica. However in 1884, when the diocese was established, the procedure for acquiring city status for new diocesan seats involved the town in question's borough council petitioning the monarch, a petition that at that time was invariably granted. As Southwell was not an incorporated borough and had no borough council to raise the petition, it never gained city status.

Today, Southwell has an active town council, which forms the first tier of local government for the whole of the civil parish of Southwell. The town council, since the 2023 elections, consists of ten Liberal Democrat (LibDem) councillors, two Conservative (Con) councillors, one Labour and one independent. The council chair was held in 2019–2021 by Mrs Lyn Harris (LibDem) and since then by Sally Reynolds (independent) and since 2021 by Martin Stott (LibDem). The Chair of the Town Environment Committee is Lyn Harris, that of the Governance and Finance Committee Peter Harris and that of the Planning Committee Jeremy Berridge (all three LibDem).

The second and third tiers of local government in the civil parish are provided by Newark and Sherwood District Council and Nottinghamshire County Council respectively. It is represented as district councillors by Karen Roberts (LibDem), Peter Harris (LibDem) and Penny Rainbow (Con).

Southwark is in the Newark parliamentary constituency, currently represented by Robert Jenrick (Con).

Landmarks

The principal landmark in Southwell is the grade-I listed Southwell Minster, the cathedral of the Anglican Diocese of Southwell and Nottingham. Behind the Minster is a partly ruined palace, once a residence of the Archbishop of York. It includes the recently restored State Chamber, Cardinal Wolsey's former dining room, and gardens among the ruins.

The town has many other historical buildings including the prebendal houses in Church Street and Westgate and the Methodist church, which has a right of way beneath it, so that the upper floor seats more than the lower. The workhouse (1824) was a prototype for many others. Owned by the National Trust, it shows its appearance in the 19th century.

Media
The local community newspaper is The Bramley, of which some 11,200 copies a month are delivered free in and around Southwell.

Local news and television programmes are provided by BBC East Midlands and ITV Central. Television signals are received from the Waltham TV transmitter, BBC Yorkshire and Lincolnshire and ITV Yorkshire can also be also received from the Belmont TV transmitter.

Local radio stations are BBC Radio Nottingham on 103.8 FM, Capital East Midlands on 96.2 FM and Smooth East Midlands on 106.6 FM.

Festivals
The annual Southwell Music Festival is held every August in Southwell Minster and other nearby venues. The Gate to Southwell Festival of roots and acoustic music is held each year in early June.

Education
The town's two infant schools (aged 3–5) are Southwell Holy Trinity C of E and Lowes Wong. The latter also teaches children aged 7–11. The local secondary school is Southwell Minster School, which also educates the choristers of the Minster and gifted musicians in its Junior Department. It has particularly good GCSE and AS/A level results for Nottinghamshire.

Secondary education in the town is predominantly provided by The Minster School, which still educates choristers of Southwell Minster. The Minster School is a Specialist College for Humanities and Music and was rated outstanding by Ofsted in 2011/2012. Pupils may also choose to attend school at Newark-on-Trent, which is about a 20-minute drive east. The School of Animal, Rural and Environmental Sciences is part of Nottingham Trent University. and offers further and higher education courses in agricultural-related subjects at its Brackenhurst campus just outside Southwell.

Roads
The town is linked to Newark and Nottingham by a C road, which was formerly designated as the A612, and to north Nottingham and villages to the west by B6386.

The A617 primary route passes 2 mi north of the town in Hockerton. The A1 and A46 trunk routes are 7 mi away in Newark.

Buses
Southwell's bus routes are operated predominantly by Nottingham City Transport and Stagecoach East Midlands. Key routes include the no. 26 Lilac Line service to Nottingham and the 28/29 to Mansfield and Newark. There are other infrequent services to nearby villages.

Railway
The nearest National Rail station to the town is over 2 mi away at Fiskerton, which has gained a small car park in recent years to cater for Southwell commuters. Rolleston station is also nearby and lies adjacent to the racecourse. Both stations are on the Nottingham-Lincoln line. East Midlands Railway provides a two-hourly service between Crewe and Newark Castle; direct trains also call at Leicester, Lincoln and Nottingham.

The town was once served by Southwell railway station, which was a stop on the Rolleston Junction-Mansfield line branch line. It was opened in 1847, but closed to passengers in 1959 and to goods traffic in 1964. The station survives as a private residence. The trackbed towards Mansfield now forms the Southwell Trail, a shared-use path; the route to Rolleston Junction is now covered by housing within the town and goes on to form a private access road to Southwell Racecourse.

Sport
Southwell is home to the following sports clubs:

 * Southwell Rugby Club, known as the Redmen, was formed in 1922–1923. In the 2011–2012 season, it won a historic treble as RFU Midlands 4 (East) North League Champions, Nottinghamshire Junior Cup winners and Nottinghamshire/Lincolnshire/Derbyshire Plate winners.
 * Southwell City Football Club, an FA Charter Standard Community Club, involves over 400 local players in 35 teams aged five years to veteran.
 * Southwell Cricket Club play at Brackenhurst Cricket Ground

Southwell Racecourse, owned by the Arena Racing Company, is situated on the outskirts of the town near Fiskerton and has an all-weather track. It hosts jump and flat racing.

Southwell has a leisure centre run by a local trust, with trustees from the community; the district council also provides limited support.

Notable people
In order of birth:
 * St Edburga of Repton was translated from Repton Abbey to Southwell and died here about AD 700.
 * Ælfric Puttoc (died 1051), Archbishop of York, died here.
 * Geoffrey Plantagenet, natural son of King Henry II of England and Archbishop of York, was ordained priest here in 1181.
 * Matthew Sylvester (c. 1636–1708), Nonconformist minister and religious writer, was born here.
 * Thomas Spofforth (1743–1826), organist, died here.
 * John Spray (c. 1768–1827), tenor singer and vicar choral for the Dublin cathedrals, was born here and sang as a boy in the Minster Choir.
 * Reginald Spofforth (1769–1827), composer and organist, was baptised here.
 * Mary Ann Brailsford, who grew the first Bramley cooking apple tree from seed, was baptised here in May 1791.
 * Rev. John Thomas Becher (1770–1848), cleric, social reformer and friend of Lord Byron, was Vicar-General of Southwell Minster in 1818–1840.
 * Richard Ingleman (1777–1838), architect and surveyor, died here.
 * Henry Stenton (1815–1887) was a first-class cricketer and Southwell solicitor.
 * Francis Tinley (1819–1889), first-class cricketer with Nottinghamshire, was born here, as was his first-class cricketing brother Vincent Tinley (1828–1899).
 * Chappell Batchelor (1822–1884), organist and first-class cricketer, was born here and sang as a boy in the Minster Choir.
 * John Hatfield (1831–1889), first-class cricketer, was born here.
 * William Horsley (1835–1864), first-class cricketer, was born and died here.
 * Sebastian Smith (1869–1948), a stage and film actor, was born here.
 * Edmond Foljambe (1890–1960), first-class cricketer, was born here.
 * Ted Hufton (1892–1967), international footballer, was born here.
 * Sir Joseph Lockwood (1904–1991), whose company helped to finance The Beatles, was born here.
 * Lilian Greenwood (born 1966), Labour MP for Nottingham South, lived in Southwell 1999–2020.
 * Robert Edward Jenrick (born 1982), Conservative MP for Newark since 2014, rents a property here.
 * Scott Loach (born 1988), League footballer, attended Southwell Minster School and played for Southwell United as a youth.

Twin towns
The town is twinned with Sées in France, Sarzana in Italy,  and Český Brod in the Czech Republic.

title: Southwell, Nottinghamshire


text: User talk:69.205.14.66

title: User talk:69.205.14.66


text:
Southwell, Dorset

Southwell (pronounced south-well) is a small coastal village in Tophill on the Isle of Portland, Dorset. As Portland and Dorset's southernmost village, it lies between Portland Bill and the villages of Easton and Weston. Though close to the Bill, the village is sheltered by hills on three sides. It is the only village on Portland not to be designated a conservation area.

The Great Southwell Landslip, named after the village, remains Britain's second largest recorded historical landslide on the east side of Portland, occurring in 1734, between Durdle Pier and Freshwater Bay, at a distance of one and a half miles.

History
Southwell has medieval origins, and was established around a natural watercourse and various springs. It is likely that the Romans developed the village water sources. The various archaeological finds around the village include Iron Age earth defences and Roman stone sarcophagi. The village grew with agricultural industry, and was surrounded by strip fields, also known as lawnsheds. From the 1840s onwards Portland saw a large increase within its population, due to the construction of Portland Harbour's Breakwaters. The island's wells and ponds could not cope, and so in 1890 work began on the digging of a deep shaft at Southwell for a new water supply. The work continued until May 1895, however the shaft was dug too deep, the water turned brackish, and the scheme has to be abandoned. The shaft, 200 feet deep, still remains underground today.

Southwell retained its small community throughout the 19th century. In 1879, the Avalanche Memorial Church, also known as the Church of St Andrew, was built within the village. At the turn of the 20th-century, some of the village's surrounding fields would be destroyed by inland quarrying. Despite this there are remaining examples between the village, and Portland Bill. With the outbreak of World War II, a number of heavy anti-aircraft batteries were constructed to protect Portland's naval base, and Portland's HAA "C Battery" was built to the western outskirts of the village, at Barrow Hill. Following the war, the battery was retained as an Off-Site Nucleus Force Battery, though it was demolished a few years later.

At the beginning of the Cold War, the Admiralty selected Barrow Hill to build a new Admiralty Gunnery Establishment. In 1959 it became part of the Admiralty Underwater Weapons Establishment (AUWE). The establishment became infamous for the discovery of a Soviet spy ring that operated from the late 1950s until 1961 when the core of the network was arrested by the British security services. The establishment closed in the 1990s when the navy left Portland, and it became the Southwell Business Park in 1997. Throughout the 20th-century Southwell continued to remain a rural community, until the 1960s when major expansion saw many large housing and bungalow estates established. In the 1980s hundreds of starter homes were also built in the village. During 2002–03, both the Sweethill estate and the fields north of Southwell Business Park were developed.

Features
Like many of the other villages on Portland, Southwell has commercial businesses, namely within the Southwell Business Park. Aside from the park, the Eight Kings pub remains the only commercial business within the village. The village had one Primary School, Southwell County Primary School. In the south of the village remains the sewerage pumping station, which was originally built in the late 1980s.

The Southwell Business Park is located to the south-west of Southwell village. Once the AUWE site was closed in the 1990s, it then became the successful Southwell Business Park, used for commercial purposes. The park provided employment for almost 500 people and became home to over 100 businesses. In 2010, the park was under new ownership, where Compass Point Estates bought the park from KPMG after going into administrative receivership. In September 2016, part of the site will be home to the Isle of Portland Aldridge Community Academy's £14 million campus, after an appeal overturned the decision of Weymouth and Portland Borough Council's planning committee to refuse permission for the build at Maritime House. The park is also the site of the Ocean Hotel, once known as the Portland Hotel, the Venue Hotel and the Ocean Hotel and Spa.

Grade listed features
Southwell has a number of buildings which are Grade listed buildings. 23 Southwell Street, and the garden wall attached to the west of 47 Southwell Street are Grade II listed. The Avalanche Memorial Church has also Grade II Listed, along with its boundary wall, since September 1978. A small Methodist Chapel, named Southwell Methodist Chapel, dating from 1849, is also Grade II listed.

The surrounding fields between Portland Bill and Southwell are made up of an ancient strip field system. These particular fields remain untouched from housing or quarrying. Aside from the fields attached to the Culverwell Mesolithic Site near Portland Bill, two separate open fields have been also been scheduled under the Ancient Monuments and Archaeological Areas Act 1979. One of these is located just south of Southwell village.

title: Southwell, Dorset


text:
Von Neumann entropy

In physics, the von Neumann entropy, named after John von Neumann, is an extension of the concept of Gibbs entropy from classical statistical mechanics to quantum statistical mechanics. For a quantum-mechanical system described by a density matrix $ρ$, the von Neumann entropy is

 * $$ S = - \operatorname{tr}(\rho \ln \rho),$$

where $$\operatorname{tr}$$ denotes the trace and ln denotes the (natural) matrix logarithm. If the density matrix $ρ$ is written in a basis of its eigenvectors $$|1\rangle, |2\rangle, |3\rangle, \dots$$ as
 * $$ \rho = \sum_j \eta_j \left| j \right\rang \left\lang j \right| ,$$

then the von Neumann entropy is merely
 * $$ S = -\sum_j \eta_j \ln \eta_j .$$

In this form, S can be seen as the information theoretic Shannon entropy.

The von Neumann entropy is also used in different forms (conditional entropies, relative entropies, etc.) in the framework of quantum information theory to characterize the entropy of entanglement.

Background
John von Neumann established a rigorous mathematical framework for quantum mechanics in his 1932 work Mathematical Foundations of Quantum Mechanics. In it, he provided a theory of measurement, where the usual notion of wave-function collapse is described as an irreversible process (the so-called von Neumann or projective measurement).

The density matrix was introduced, with different motivations, by von Neumann and by Lev Landau. The motivation that inspired Landau was the impossibility of describing a subsystem of a composite quantum system by a state vector. On the other hand, von Neumann introduced the density matrix in order to develop both quantum statistical mechanics and a theory of quantum measurements.

The density matrix formalism, thus developed, extended the tools of classical statistical mechanics to the quantum domain. In the classical framework, the probability distribution and partition function of the system allows us to compute all possible thermodynamic quantities. Von Neumann introduced the density matrix to play the same role in the context of quantum states and operators in a complex Hilbert space. The knowledge of the statistical density matrix operator would allow us to compute all average quantum entities in a conceptually similar, but mathematically different, way.

Let us suppose we have a set of wave functions |Ψ〉 that depend parametrically on a set of quantum numbers n1, n2, ..., nN. The natural variable which we have is the amplitude with which a particular wavefunction of the basic set participates in the actual wavefunction of the system. Let us denote the square of this amplitude by p(n1, n2, ..., nN). The goal is to turn this quantity p into the classical density function in phase space. We have to verify that p goes over into the density function in the classical limit, and that it has ergodic properties. After checking that p(n1, n2, ..., nN) is a constant of motion, an ergodic assumption for the probabilities p(n1, n2, ..., nN) makes p a function of the energy only.

After this procedure, one finally arrives at the density matrix formalism when seeking a form where p(n1, n2, ..., nN) is invariant with respect to the representation used. In the form it is written, it will only yield the correct expectation values for quantities which are diagonal with respect to the quantum numbers n1, n2, ..., nN. Expectation values of operators which are not diagonal involve the phases of the quantum amplitudes. Suppose we encode the quantum numbers n1, n2, ..., nN into the single index i or j. Then our wave function has the form

 * $$ \left| \Psi \right\rangle = \sum_i a_i \left| \psi_i \right\rangle . $$

The expectation value of an operator B which is not diagonal in these wave functions, so

 * $$ \left\langle B \right\rangle = \sum_{i,j} a_i^{*}a_j \left\langle i \right| B \left| j \right\rangle .$$

The role which was originally reserved for the quantities $$ \left| a_i \right| ^2$$ is thus taken over by the density matrix of the system S.

 * $$ \left\langle j \right| \rho \left| i \right\rangle = a_j a_i^{*} .$$

Therefore, 〈B〉 reads
 * $$ \left\langle B \right\rangle = \operatorname{tr} (\rho B) .$$

The invariance of the above term is described by matrix theory. The trace is invariant under cyclic permutations, and both the matrices $ρ$ and B can be transformed into whatever basis is convenient, typically a basis of the eigenvectors. By cyclic permutations of the matrix product, it can be seen that an identity matrix will arise and so the trace will not be affected by the change in basis. A mathematical framework was described where the expectation value of quantum operators, as described by matrices, is obtained by taking the trace of the product of the density operator $$\hat{\rho}$$ and an operator  $$\hat{B}$$   (Hilbert scalar product between operators). The matrix formalism here is in the statistical mechanics framework, although it applies as well for finite quantum systems, which is usually the case, where the state of the system cannot be described by a pure state, but as a statistical operator $$\hat{\rho}$$ of the above form. Mathematically, $$\hat{\rho}$$ is a positive-semidefinite Hermitian matrix with unit trace.

Definition
Given the density matrix ρ, von Neumann defined the entropy as

 * $$S(\rho) = -\operatorname{tr} (\rho \ln \rho),$$

which is a proper extension of the Gibbs entropy (up to a factor $k_{B}$) and the Shannon entropy to the quantum case. To compute S(ρ) it is convenient (see logarithm of a matrix) to compute the eigendecomposition of  $$~\rho = \sum_j \eta_j \left| j \right\rangle \left\langle j \right| $$. The von Neumann entropy is then given by

 * $$S(\rho) = - \sum_j \eta_j \ln \eta_j .$$

Properties
Some properties of the von Neumann entropy:

 * $S(ρ)$ is zero if and only if $ρ$ represents a pure state.
 * $S(ρ)$ is maximal and equal to $$\ln N$$ for a maximally mixed state, $N$  being the dimension of the Hilbert space.
 * $S(ρ)$ is invariant under changes in the basis of $ρ$, that is, $S(ρ) = S(UρU^{†})$, with $U$ a unitary transformation.
 * $S(ρ)$ is concave, that is, given a collection of positive numbers $λ_{i}$ which sum to unity ($$\Sigma_i \lambda_i = 1$$) and density operators $ρ_{i}$, we have
 * $$ S\bigg(\sum_{i=1}^k \lambda_i \rho_i \bigg) \geq \sum_{i=1}^k \lambda_i S(\rho_i). $$

 * $S(ρ)$ satisfies the bound
 * $$ S\bigg(\sum_{i=1}^k \lambda_i \rho_i \bigg) \leq \sum_{i=1}^k \lambda_i S(\rho_i) - \sum_{i=1}^k \lambda_i \log \lambda_i. $$
 * where equality is achieved if the $ρ_{i}$ have orthogonal support, and as before $ρ_{i}$ are density operators and $λ_{i}$ is a collection of positive numbers which sum to unity ($$\Sigma_i \lambda_i = 1$$)

 * $S(ρ)$ is additive for independent systems. Given two density matrices  $ρ_{A}, ρ_{B}$ describing independent systems A and B, we have
 * $$S(\rho_A \otimes \rho_B)=S(\rho_A)+S(\rho_B)$$.

 * $S(ρ)$ is strongly subadditive for any three systems A, B, and C:
 * $$S(\rho_{ABC}) + S(\rho_{B}) \leq S(\rho_{AB}) + S(\rho_{BC}).$$
 * This automatically means that $S(ρ)$ is subadditive:
 * $$S(\rho_{AC}) \leq S(\rho_{A}) +S(\rho_{C}).$$

Below, the concept of subadditivity is discussed, followed by its generalization to strong subadditivity.

Subadditivity
If $ρ_{A}, ρ_{B}$ are the reduced density matrices of the general state $ρ_{AB}$, then
 * $$ \left| S(\rho_A) - S(\rho_B) \right| \leq S(\rho_{AB}) \leq S(\rho_A) + S(\rho_B) . $$

This right hand inequality is known as subadditivity. The two inequalities together are sometimes known as the triangle inequality. They were proved in 1970 by Huzihiro Araki and Elliott H. Lieb. While in Shannon's theory the entropy of a composite system can never be lower than the entropy of any of its parts, in quantum theory this is not the case, i.e., it is possible that $S(ρ_{AB}) = 0$, while $S(ρ_{A}) = S(ρ_{B}) > 0$.

Intuitively, this can be understood as follows: In quantum mechanics, the entropy of the joint system can be less than the sum of the entropy of its components because the components may be entangled. For instance, as seen explicitly, the Bell state of two spin-½s,
 * $$ \left| \psi \right\rangle = \left| \uparrow \downarrow \right\rangle + \left| \downarrow \uparrow \right\rangle ,$$

is a pure state with zero entropy, but each spin has maximum entropy when considered individually in its reduced density matrix. The entropy in one spin can be "cancelled" by being correlated with the entropy of the other. The left-hand inequality can be roughly interpreted as saying that entropy can only be cancelled by an equal amount of entropy.

If system $A$ and system $B$ have different amounts of entropy, the smaller can only partially cancel the greater, and some entropy must be left over. Likewise, the right-hand inequality can be interpreted as saying that the entropy of a composite system is maximized when its components are uncorrelated, in which case the total entropy is just a sum of the sub-entropies. This may be more intuitive in the phase space formulation, instead of Hilbert space one,  where the Von Neumann entropy amounts to minus the expected value of the ★ -logarithm of the Wigner function,  $−∫ f ★ log_{_{★} }f dx dp$,  up to an offset shift. Up to this normalization offset shift, the entropy is majorized by that of its classical limit.

Strong subadditivity
The von Neumann entropy is also strongly subadditive. Given three Hilbert spaces, A, B, C,

 * $$S(\rho_{ABC}) + S(\rho_{B}) \leq S(\rho_{AB}) + S(\rho_{BC}).$$

This is a more difficult theorem and was proved first by J. Kiefer in 1959   and independently by Elliott H. Lieb and Mary Beth Ruskai in 1973, using a matrix inequality of Elliott H. Lieb proved in 1973. By using the proof technique that establishes the left side of the triangle inequality above, one can show that the strong subadditivity inequality is equivalent to the following inequality.

 * $$S(\rho_{A}) + S(\rho_{C}) \leq S(\rho_{AB}) + S(\rho_{BC})$$

when $ρ_{AB}$, etc. are the reduced density matrices of a density matrix $ρ_{ABC}$. If we apply ordinary subadditivity to the left side of this inequality, and consider all permutations of A, B, C, we obtain the triangle inequality for $ρ_{ABC}$: Each of the three numbers $S(ρ_{AB}), S(ρ_{BC}), S(ρ_{AC})$ is less than or equal to the sum of the other two.

Canonical ensemble
Theorem. The canonical distribution is the unique maximum of the Helmholtz free entropy $f[\hat\rho]$, which has the solution$$\hat\rho(\beta) = \sum_i e^{-\beta E_i}| i \rangle \langle i | = e^{-\beta \hat H}$$in the eigenbasis of the Hamiltonian operator $\hat H$. This state has free entropy$$f = \ln Z$$where $Z = \sum_i e^{-\beta E_i} = Tr(\hat\rho)$ is the partition function.

Equivalently, the canonical distribution is the unique maximum of entropy under constraint:$$\begin{cases} \max S[\hat \rho] \\ \langle H\rangle = E \end{cases}$$

Coarse graining
Since, for a pure state, the density matrix is idempotent, ρ = ρ2, the entropy S(ρ) for it vanishes. Thus, if the system is finite (finite-dimensional matrix representation), the entropy S(ρ) quantifies the departure of the system from a pure state. In other words, it codifies the degree of mixing of the state describing a given finite system.

Measurement decoheres a quantum system into something noninterfering and ostensibly classical; so, e.g., the vanishing entropy of a pure state $$\Psi = ( \left| 0 \right\rangle + \left| 1 \right\rangle ) / \sqrt{2}$$, corresponding to a density matrix
 * $$\rho = {1\over 2} \begin{pmatrix}

1 & 1 \\ 1 & 1 \end{pmatrix}  $$ increases to $S = \ln 2 \approx 0.69$ for the measurement outcome mixture
 * $$\rho = {1\over 2} \begin{pmatrix}

1 & 0 \\ 0 & 1 \end{pmatrix}  $$ as the quantum interference information is erased.

However, if the measuring device is also quantum mechanical, and it starts at a pure state as well, then the joint system of device-system is just a larger quantum system. Since it starts at a pure state, it ends up with a pure state as well, and so the von Neumann entropy never increases. The problem can be resolved by using the idea of coarse graining.

Concretely, let the system be a qubit, and let the measuring device be another qubit. The measuring device starts at the $$\left| 0 \right\rangle $$ state. The measurement process is a CNOT gate, so that we have $$\left| 0 \right\rangle \left| 0 \right\rangle \mapsto \left| 0 \right\rangle\left| 0 \right\rangle $$, $$\left| 1 \right\rangle \left| 0 \right\rangle \mapsto \left| 1 \right\rangle\left| 1 \right\rangle $$. That is, if the system starts at the pure 1 state, then after measuring, the measurement device is also at the pure 1 state.

Now if the system starts at the $$\Psi = ( \left| 0 \right\rangle + \left| 1 \right\rangle ) / \sqrt{2}$$ state, then after measurement, the joint system is in the Bell state $$( \left| 0 \right\rangle \left| 0 \right\rangle + \left| 1 \right\rangle \left| 1 \right\rangle) / \sqrt{2}$$. The vN entropy of the joint system is still 0, since it's still a pure state. However, if we coarse grain the system by measuring the vN entropy of just the device, then just the qubit, then add them together, we get $$2\ln 2$$.

By subadditivity, $$S(\rho_{AB}) \leq S(\rho_{A}) + S(\rho_{B}) $$, that is, any way to coarse-grain the entire system into parts would equal or increase vN entropy.

title: Von Neumann entropy


text:
Virtualtourist

VirtualTourist (VT) was a free online travel guide and social networking service. The website had over 1.3 million members, which contributed to sharing 3.7 million photos and posted 1.8 million travel tips for over 70,000 locations. Members were able to rate each other's tips by accuracy and helpfulness. Each member had a "VT rank" based on the ratings of their tips.

Some members attended meetings, which often included over 100 participants.

The company also provided "Top 10 lists" based on rankings by its members, including "10 of world's most unusual foods", "Top 10 European Cities To See Now", and "Best Street Art".

The site earned honors including recommended travel forum by Time, a favorite website by Newsweek, and one of the 35 best travel sites by Travel + Leisure.

Effective February 27, 2017, the site was shut down.

History
The origin of Virtualtourist is found in a project at the University of Buffalo to provide a Web-based map of all servers on the Internet. This project was nominated for “Best Navigation Aid” at the Best of the Web Awards at the First International Conference on the World-Wide Web.

In 1996, Brandon Plewe at the University of Buffalo registered “Virtual Tourist” as a trademark in the US, but abandoned the trademark in 1997. Shortly thereafter, two German computer science students, Tilman Reissfelder and Thorsten Kalkbrenner at the University of Karlsruhe, registered the URL.

By 1999, Reissfelder and Kalkbrenner had a site with a few hundred city locations with travel links that people could add to and which would reference their user profiles. The site, which had links about “Hotels, Restaurants, Things to Do”, received 1.5 million page views per month from about 500,000 unique visitors. J.R. Johnson, an American attorney, teamed up with Reissfelder and Kalkbrenner, moved the company to the US, raised money, with Reissfelder as CTO and Johnson as CEO.

The website launched in January 2000 at the peak of the dot-com bubble.

In 2007, the company launched VirtualTourist Travel Guides, printed guidebooks composed almost entirely of user-generated content.

In July 2008, VirtualTourist.com, Inc. and sister site Onetime were acquired by Expedia Group (then owner of TripAdvisor) for $85 million.

In September 2012, the company announced a partnership whereby it would provide perks to travelers with Contiki Tours who posted about their experiences on the website.

Effective February 27, 2017, the site was shut down.

title: Virtualtourist


text:
Wikipedia:Featured article review/Asperger syndrome/archive1

Asperger syndrome

 * This article is still a featured article

Though the article may be comprehensive it does not meet the stability requirements of a featured article as well as the fact that it is not easy to read and does not conform to the style guide and the writing is all over the place and the article is highly disputed and the subject of many edit wars, see:Asperger's syndrome page history. Jtkiefer T - 21:56, August 22, 2005 (UTC)
 * Perhaps you could be so kind as to more specifically point out what features of the article, outside of the recent edit war, lead you to say that? For example, I find the article as a whole much better written and easier to understand than the majority of Wikipedia articles I've seen (not to mention your own description of it above!). Also, what features of it have been disputed recently by anyone other than Tern? I do not mean to be snide; my interest is in improving it. So far all the comments I've seen on this subject have been rather vague, and we Aspies don't handle vagueness well :-). 24.77.97.3 08:20, 23 August 2005 (UTC)

Wikipedia's entire ethics would be dead unless these medical censors' mob game comes out of this banned. FA status removal is the least they have brought on themselves for trying to turn the artricle into their own controlled biased soapbox. - Tern, 01:26! Aug''' 23  Keep . As noted above, the "controversy" is entirely the work of one user. The person denying this above is that one user, who among other things, is now claiming that phrases like "terrible cruelty" - a paradigm case of POV - are neutral and even "axiomatic". Feel free to visit the talk page and confirm this for yourself. Ironically many of Tern's above accusations could be more accurately applied to himself, particularly the last two. 24.77.97.3 01:04, 23 August 2005 (UTC)
 * Personally, I think this was from the Brillant Prose crop of articles. Most of the articles from there have went to FARC and usually are delisted. So, until we get this figured out, I support the removal of the FA status. Zscout370 (Sound Off) 22:13, 22 August 2005 (UTC)
 * It was promoted on 10 April 2004 with 10 supports, including a resolved objection (here is the position from the WP:FAC page history immediately before it was promoted). For some reason, fac was added when it was promoted, on 10 April 2004 (diff), and was not replaced by featured until 20 June 2004 (diff). -- ALoan (Talk) 11:20, 23 August 2005 (UTC)
 * 'Keep due to the valiant efforts of the Wikipedians at the article. Zscout370 (Sound Off) 23:25, 23 August 2005 (UTC)
 * Remove No it isn't, a lot of its content is controversial. See the talk page for that,as well as for what has been going on in the last few days: a fantastical eruption of hate vendetta against one person, by voices including this Ryan who
 * reject all efforts to find a mutually inclusive edit of the subject they object to
 * never give an alternative point of view on the issue, just keep claiming it doesn't matter
 * reject anything else than total deletion of all mention of it, even though it involves child cruelty towards the group this medical article is about
 * base their arguments mostly on personal prejudice and personal attacks
 * are trying to force this by repeating the same delete-vandalism at high frequency, and in ways that have been demonstrated personally malicious as you can see if you go there and look at the history or the discussion, then filing malicious 3RR charges when stood up to
 * Hey, given that this user is indefinitely blocked, does the above vote count? (To be clear, he was not blocked at the time he voted, however he has since been blocked indefinitely for his many and various policy violations and generally needlessly antagonistic behaviour.)
 * Keep. I don't like removing an article from FA status only a few days into an edit war. Afterall, these things happen all the time and tend to resolve themselves within a week or two. While the article may have other issues, it is difficult to tell at this point. I'd be happy to revisit this issue in a month or so. If the article is still unstable then, I would vote to remove.--Alabamaboy 00:45, 23 August 2005 (UTC)
 * Your views are appreciated and have been noted however your vote cannot be counted since you are an IP, if you would like you are welcome to create an account and revote or sign your name to this vote. Jtkiefer  T - 02:51, August 23, 2005 (UTC)
 * Tern's tendency towards retaliation on other sites precludes that, sorry. I have made over 150 edits to various pages, all under the same IP, only one of which has been seriously disputed (not to the Asperger page); I think I'm a legitimate contributer. I'd be happy to contact you somewhere other than publically available parts of Wikipedia with any personal information that might help make an exception to this rule (which I can't seem to find documentation of, by the way, though it's possible I'm not looking in the right place). Failing that, I guess I'll have to accept having my vote not count for this particular purpose. 24.77.97.3 08:20, 23 August 2005 (UTC)
 * This is 24.77.97.3. I have reconsidered the above, and have now created an account. Thus my vote can now be added to the keep side. (I still can't find that rule, by the way.) PurplePlatypus 02:14, 25 August 2005 (UTC)

 * Note: as noted in my nomination of this for FARC it isn't just the edit warring that led me to put this up for deletion removal, it's also that the article is not especially a greatly written article and doesn't seem to fit the criteria for a featured article and the guide for style. Jtkiefer  T - 02:48, August 23, 2005 (UTC)
 * Note, the article is not up for deletion, we are just seeing if it is even worthy for the FA status. Zscout370 (Sound Off) 02:54, 23 August 2005 (UTC)

 * [keep] Controversy will always exist with "disorders" such as AS. It's not clearly defined and it includes a huge range from low to high functioning.  Personally, I clearly have several of the traits - more than one in each of the categories defined by the DSM-IV.  I'd say the ability for intense focus is quite the counter-balance to the lack of social ability; which as I must be high-fuctioning, it is hardly that limiting.  So you're a bit colder than most, have problems expressing your feelings, and get very uncomfortable in large groups; many social people get uncomfortable in small groups... [take  that for what it's worth]

 * I tend to think this disorder should be defined in more detail, and should be geared towards low-functioning aspies. As those who are high functioning can use AS to their adv. in the real world .  One could actually argue that being a high-functioning Aspie is actually adaptive... specialization and a tendancy to focus on logic is a good combo for success if you can adapt to the lack of social skills.

 * Nonetheless... Wikipedia's page defines AS better than any other site out there and should not be removed as a FA. It's not that the article is poorly done, but rather that the key/core issues involving AS are controversal and up for debate... me thinks this article does a decent job at presenting the different angles. ** - Oilers99fan

 * KEEP Article is much better now. If there are any style problems please mention them and they will be corrected -- Ryan Norton T 11:41, 23 August 2005 (UTC)

 * Keep. The article, as RN mentions, is much improved. The main problems it had before were stylistic, and the page was pretty stable until the edit war with Tern broke out. Oilers99fan has a good point in that there will always be some controversy in the core of the debate, but the page is comprehensive. ManekiNeko 21:25, 23 August 2005 (UTC)

 * Keep. The edit war has abated, and cooler heads are prevailing. The article has retained the informational value it had when it ascended to FA status, NPOV--from my POV, at least--is returning, and from what I can tell, all vandalism (by any rational definition) has been cleaned up, and the source has been dealt with. I agree with ManekiNeko: the page is comprehensive. matt 20:08, 24 August 2005 (UTC)

 * The truth of the above is to be tested during the day starting now. The statement "The source has been dealt with" is a continuing expression of personal victimisation that does not bode well, and only if it is shown not to be true and this kind of thing is stamped out will everything else Matt has said become true. In fact lagre parts of the article have been thoroughly rewritten in a check for fairness by those editors who realised they were under wider scrutiny now for the personal stuff to stop and a basis for neutral common ground to be found.tern 02:36, 25 August 2005 (UTC)

 * You know very well, or should, that non-neutrality has nothing to do with why they were rewritten. PurplePlatypus 04:11, 25 August 2005 (UTC)

 * Keep. Though the grammar could use improvement and it might be better to remove the culture section from the article altogether. This article is overall a very good read. Cedars 02:25, 28 August 2005 (UTC)

 * Keep I came to the talk page to make sure it had already been featured. --Ryan Delaney talk 03:33, 1 September 2005 (UTC)

 * Keep The article has grown a lot of late, which is true of many articles as Wikipedia has proliferated. But unlike some other expanding articles it has retained most of it's sense of style and accuracy, while substantially improving it's depth. A definate keep. D-Katana 01:29, 4 September 2005.


text: File:Camper Van Beethoven - Our Beloved Revolutionary Sweetheart.jpg


text: User talk:68.40.230.32

title: User talk:68.40.230.32


text:
Talk:IP multicast

Moving Addressing to Routing Schemes
I think the Addressing section should be moved. At least some of it. Those things relevant to multicasting are ok, but anycasts or unicasts have hardly anything to do with IP Multicasting. Opinions? -def Mon Jul 24 2006

 * I moved that section to the IP address article. Maybe it is not the best location, but it fits better there than here. Sega381 (talk) 23:59, 20 August 2013 (UTC)

Cleanup notice
Gah. Product boosting and advertising blather. Not the hottest writing either. I don't have time today to clean it up, but I'll try to take a crack at it Real Soon Now. Anville 21:58, 22 August 2005 (UTC)

Tossed in a very brief overview on the Temp page. Provides a brief definition and some vendor-neutral technical details. Since I wrote the whole thing myself, it should be immune to copyright violations. Of course, that doesn't necessarily mean it's good enough quality...196.41.167.243 12:01, 24 August 2005 (UTC)

It seems that the writer of this article does not have a good grasp of the English language. I would prefer an article written by a native speaker.

 I haven't created this document, but it makes sense to me to have distinct documents for IP Multicast and the abstract meaning of Multicast, so I'm positive for a merge of the IP Multicast part in Multicast into here. What do you think?

@SymlynX: Makes sense to do so...

Seems good. --anonymous

Rewrite
I have merged the content from Multicast, but ended up rewriting most of it. Sadly wasn't signed in when I made the change, but 2006-07-11 21:08:36 203.2.96.1 was me. It still needs work, but it's better than it was. Stephen.frede 10:14, 11 July 2006 (UTC)

Complete update started
It's going to take quite a bit of doing as IP multicast is a pretty large subject, but I made a start at it today in the first few sections. Long way to go and a lot of ground to cover, but hopefully I can get it done. Hopefully none of the past editors take offense to my going gung ho, but I hope you'll find my contributions worthwhile. I think you'll find I have a fair bit of multicast expertise, but feel free to challenge me if there is something major you don't like. I do expect to have some bits and pieces fixed up by others as my writing can sometimes be a little hectic and not always well organized as I move from topic to topic. [ update: silly cookie, expired, this is me jtk ]

While at it, multicast security [MSEC] is another topic missing. --anonymous

Inappropriate Tone
The use of second-person conversational tone as well as several other unencyclopaedic statements is inappropriate. The text of this article be revised.

For example: "You might now be wondering about the efficiency..."

go ahead and change the tone where you find it lacking, but please be careful with the technical details, that is the part I am focusing on jtk Sun Jul 23 03:41:15 GMT 2006

Changed a few of the tone thingies -def Mon Jul

Some of the multicast security work (particularly relatated to crypto and group authentication) might be well suited for a separate article. Much of that work is academic and not widely deployed. I know less about it, so if someone wants to take a stab at it go for. Though I can envision that being a separate article as I said. jtk Fri Sep 1 15:52:49 GMT 2006

Integrate these paragraphs?
The following text blocks stem from the Multicast document but since they are about IP Multicast they don't belong there. Feel free to integrate in this document. -SymlynX 11:09, 7 September 2006 (UTC)

Link local multicast, where IP Multicast packets are sent to groups of hosts on the same physical or virtual data link layer, does not require complex routing, and is therefore much more widely deployed. It is used in IPv6 for address resolution, and in zeroconf networks for service discovery, name resolution, and address conflict resolution, replacing inefficient broadcast protocols.

Multicast security is a major issue. Standard, practical, communications security solutions normally employ symmetric cryptography. But applying that to IP Multicast traffic would enable any of the receivers to pose as the sender. The IETF MSEC workgroup is developing security protocols to solve this problem, mostly within the architectural framework of the IPsec protocol suite.

IPsec cannot be used in the multicast scenario because IPsec security associations are bound to two hosts and not many. IETF proposed a new protocol TESLA, which is quite convincing and flexible for multicast security.

Multicast security has been an active area of interest for some time. Standard, practical, communications security solutions normally employ symmetric cryptography. But applying that to IP Multicast traffic would enable any of the receivers to pose as the sender. The IETF MSEC workgroup is developing security protocols to solve this problem, mostly within the architectural framework of the IPsec protocol suite.

Hoot-n-holler?
Can anyone say what a "hoot-n-holler" system is? The article refers to it, but Wikipedia doesn't have an entry.... --Alvestrand 06:41, 22 September 2006 (UTC)

 * Found a def. . Now to make an article from it... --Alvestrand 06:43, 22 September 2006 (UTC)

Applications and Protocols?
There are currently no links between this topic and the topics covering applications using multicast.

At least the "Applications" paragraph could note that "multicast is supported by protocols such as Real Time Streaming Protocol and applications such as Windows Media Player". I'd add this myself, but the discussion page indicates that people have spent quite some time tidying this page up.

Thog 203.59.28.111 07:01, 27 October 2006 (UTC)

Small fix for Reliable Multicast
Under Reliable Multicast is says "...can request that the packet be resent using a simple unicast connection." What connection ? A packet resend does not need any connection. Is the mising packet resent over TCP ? --Xerces8 13:20, 31 January 2007 (UTC)

Layer 2 support
I miss details about multicast implementation on Layer-2 (ethernet switches). Is it in another article ? I'm am especially interested about low-cost and SoHo switches. --Xerces8 13:20, 31 January 2007 (UTC)
 * I've added some more information on layer-2 implementation. I've not added any specific vendor information, but AFAIK most low-cost switches will not implement IGMP snooping, but many low-end switches (not low cost) of 3com, Cisco, etc, do. --Javifs November 2007 —Preceding comment was added at 16:11, 21 November 2007 (UTC)

Many low end switches support neither IGMP snooping nor multicast flooding. They simply don't pass on multicast. I have just finished troubleshooting DLNA traffic which is Upnp/Multicast. My Tenda switch doesn't pass multicast under any circumstances and my TP-Link only passes multicast until it has built its Mac table. So I am looking for a new switch. D-Link tell me for example that only their managed switches ie mid range and above support either or both of multicast flooding and IGMP snooping. --PaulC January 2013

 * This is WP:OR. I think you are also mistaken. Or your switch is broken or "Many" is a gross exaggeration. I have reverted your change. If you want to resore it, please find a WP:RS that supports this. -—Kvng 03:28, 19 January 2013 (UTC)

Small fixes for Reliable Multicast and Layer 2 support
As Xerces8 pointed out above under Reliable Multicast it says "...can request that the packet be resent using a simple Unicast connection." What connection? A packet resend does not need any connection. Is the missing packet resent over TCP?

According to PGM's co creator, PGM design was to re-multicast missing packet information, thus avoiding an implosion of replacement requests with corresponding Unicast packet replacement data. Also, Hulkster added newer information about PGM-CC. PGM-CC is a congestion control attempt that steps the bandwidth down to the worst receiver in the group. This is controversial because the other group members are made to suffer the step down and resultant quality loss.

About the details of implementation on Layer-2: IP Multicast is mapped into corresponding Ethernet address space and even low quality SOHO switching routers pass the Multicast datagrams to the fellow downstream (neighboring) interfaces. Better quality SOHO routers (like Linksys and D-link) also snoop for IGMP V2(V3) join messages (IGMP Version 3 support in newer units). When received they pass the IGMP messages to the upstream interface and flow the IP Multicast to the end users as long as someone remains in the group.

Higher end routers also do a routine query to make sure someone is still interested (joined) to the group. Because IGMP is a connectionless protocol, multiple IGMP messages are sent to be sure that all interested parties have heard the (still there?) message. This scheme proves to be problematic in a SOHO radio LAN environment because packet loss is so high in these environments that even several (still there?) messages might not be heard causing the group to be shut down by the SOHO router. Hulkster will edit the Ethernet section as necessary.

--Hulkeypoo 16:27, 3 October 2007 (UTC)

Steve Deering
Shouldn't this page mention that Steve Deering invented IP Multicast and developed it as his Ph.D. thesis? -- Steve Casner —Preceding unsigned comment added by Slcasner (talk • contribs) 19:59, 25 May 2008 (UTC)

 * We probably should, though we'll need some sourcing for verification. I would avoid the term "invented" (perhaps proposed the concept?).  /Blaxthos ( t / c ) 21:40, 25 May 2008 (UTC)

contrary to carrier business models
another reason multicast is rarely available "to the end user" is that offering it is contrary to the business model of a carrier who charges for bandwidth. I don't have a citation for this sensible obersvation however.

Torrent-like protocols (such as torrent) that self-organize to reduce long-haul bandwidth, and reduce the load on an originating server, have eased the pain somewhat too. —Preceding unsigned comment added by 75.87.135.149 (talk) 00:35, 16 March 2010 (UTC)

Broken Link?
The second-to-last external Reference, "(Frequently Asked Questions (FAQ)), Multicast Tech, retrieved 2010-11-18." points to http://www.multicasttech.com/faq/. The site is in German, and (from my limited knowledge of German) does not appear to have anything to do with IP multicasting. — Preceding unsigned comment added by 205.210.223.133 (talk) 16:55, 21 January 2013 (UTC)

Addressing Section
There is no such thing as anycast addressing in IPv4.

This revision was partly right:

http://en.wikipedia.org/w/index.php?title=IP_multicast&oldid=514322068

I would suggest to remove the addressing section, or at least the part on anycast.

--Gregory.lussier (talk) 13:15, 31 May 2013 (UTC)
 * Well, the article should cover IP in general, not just IPv4. I believe I have distinguished the two, to address your concern. Kbrose (talk) 17:43, 31 May 2013 (UTC)

 * I moved that section to IP address, since it talks about different addressing methods, including multicast, which is the only focus of this article. That section was much broader in scope than this article. Sega381 (talk) 00:01, 21 August 2013 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 11 external links on IP multicast. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20110526111518/http://www.nordu.net/conference2006/presentations/We11_NORDUnet2006.pdf to http://www.nordu.net/conference2006/presentations/We11_NORDUnet2006.pdf
 * Added tag to http://mediatools.cs.ucl.ac.uk/nets/mmedia/
 * Added archive https://web.archive.org/web/20071126235623/http://www.venaas.no/multicast/ssmping/ to http://www.venaas.no/multicast/ssmping/
 * Added archive https://web.archive.org/web/20070826161743/http://www.kloosterhof.com/~wilbert/igmpv3.html to http://www.kloosterhof.com/~wilbert/igmpv3.html
 * Added tag to ftp://parcftp.xerox.com/pub/net-research/ipmulti/
 * Added archive https://web.archive.org/web/20071224133547/http://netweb.usc.edu/pim/ to http://netweb.usc.edu/pim/
 * Added archive https://web.archive.org/web/20070909152315/http://www.nexthop.com/products/gated.html to http://www.nexthop.com/products/gated.html
 * Added archive https://web.archive.org/web/20071015124705/http://antc.uoregon.edu/GATED/ to http://www.antc.uoregon.edu/GATED/
 * Added archive https://web.archive.org/web/20071203150138/http://www3.ietf.org/html.charters/rmt-charter.html to http://ietf.org/html.charters/rmt-charter.html
 * Added archive https://web.archive.org/web/20071214221047/http://www.ietf.org/html.charters/magma-charter.html to http://ietf.org/html.charters/magma-charter.html
 * Added archive https://web.archive.org/web/20071202041753/http://www.ietf.org/html.charters/pim-charter.html to http://ietf.org/html.charters/pim-charter.html
 * Added archive https://web.archive.org/web/20070127090246/http://www.ietf.org/html.charters/ssm-charter.html to http://ietf.org/html.charters/ssm-charter.html
 * Added archive https://web.archive.org/web/20071216145244/http://www.ietf.org/html.charters/msec-charter.html to http://ietf.org/html.charters/msec-charter.html

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 08:34, 10 November 2017 (UTC)

Deployment
Multiple statements in the Deployment section have been marked as unverified for some time. I went to find some sources to support these statements and was not immediately successful. I found things like this instead. IP multicast is available on most enterprise-grade network equipment. It is generally not enabled by default and my experience is that it is not routinely enabled on enterprise networks. No one now expects IP multicast to be made available over large networks such as the internet. Intrinsic reliability issues with multicast delivery limit the sorts of applications that can use it effectively. Content delivery networks are providing services we once thought would be delivered via multicast. ~Kvng (talk) 15:53, 3 December 2017 (UTC)

Each application must not join
In the "Routing" section, we find the statement:

"Each host (and in fact each application on the host) that wants to be a receiving member of a multicast group [...] must use the Internet Group Management Protocol (IGMP) to join"

But at least in Linux which is one of the most common network device operating systems, that is not a true statement. Indeed, it suffices that one application joins for all applications to be able to receive the multicast stream.

2001:1BA8:1614:E800:E898:43BD:1005:28D9 (talk) 07:31, 22 July 2020 (UTC) Daniel Janzon

 * To describe this from a network perspective, the parenthetical is unnecessary and potentially distracting. What applications are required to do to receive multicasts is OS dependent. I have deleted the parenthetical. ~Kvng (talk) 13:22, 25 July 2020 (UTC)

title: Talk:IP multicast


text:
User talk:JeahSon

Welcome!

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text:
Tonia Kwiatkowski

Tonia Sue Kwiatkowski (born February 12, 1971) is an American figure skating coach and former competitor. She is a two-time Winter Universiade champion, a two-time Champions Series silver medalist, and the 1996 U.S. National silver medalist in women's singles. She finished in the top ten at two World Championships and competed in 13 U.S. Championships. Carol Heiss Jenkins and Glyn Watts were her longtime coaches. Kwiatkowski retired from amateur skating in 1998 and continues to be involved in the sport as a skater and coach.

In domestic competition, she represented the Winterhurst Figure Skating Club based in the suburbs of Cleveland, Ohio.

Personal life
Kwiatkowski was born on February 12, 1971, in Cleveland, Ohio. She graduated from Lakewood High School in Ohio. In June 1994, she earned a degree in communications and psychology from Cleveland's Baldwin-Wallace College.

She was frequently lauded by television commentators for pursuing her post-secondary education.

While Debi Thomas (Stanford BA, Northwestern MD) and Paul Wylie (Harvard BA, MBA) had managed to continue post-secondary education while competing at the highest levels of the sport in the 1980s, among Kwiatkowski's peers there were few skaters pursuing a college degree. According to a March 18, 1996, Los Angeles Times article, Kwiatkowski's college degree was notable as "...most of her competitors have not finished high school."

Kwiatkowski later married and had a child. She divorced after a 2011 FBI investigation exposed her affair with convicted felon William Neiheiser.

Skating style and repertoire
Kwiatkowski was well-known among skaters for her unusual jump entrance technique into the triple lutz. Skating backward, she would cross her left foot over the top of her right foot, pause with both feet on the ice placed closely together, then unhook the right foot (underneath and behind the left) to pick into the ice.

In addition to the triple lutz, Kwiatkowski frequently performed the triple toe loop, triple flip, and triple loop. She had a higher success rate on toe-assisted jumps, as she frequently struggled on the edge-entrance triple loop, and only added the triple salchow back into her performance repertoire near the end of her amateur skating career. Her spins were fast with clean positions, and her basic skating quality was marked by great speed.

As she matured and as fashions in the sport changed, so did Kwiatkowski's image. By the mid-1990s, she often selected a tight, low bun as an on-ice hairstyle, coupled with elegant dresses with highly detailed beading and design details. During her prime competitive years in the mid-1990s, her adult physique and mode of dress distinguished her from most of her "baby ballerina" (a term frequently used by Dick Button in commentary for the U.S. Nationals as televised on ABC) rivals, who were typically 5 to 10 years her junior and usually did not attempt the mature look that Kwiatkowski achieved. This did not go unnoticed by the press, as evidenced by an AP article dated April 5, 1998, noting of Kwiatkowski's World Championship performances that "...her spins were lovely, and her age gives her a grace few other skaters can match."

1993 season
After several strong finishes at the U.S. Nationals, Kwiatkowski made the World Championship team in 1993, an unusual year in figure skating: it was a post-Olympic year and pre-Olympic year, as the Winter Games were being switched to a different cycle so that they occurred two years after the Summer Games. As such, several 1992 Olympic hopefuls had moved on.

Typically a "rebuilding" year for the sport, this post-Olympic year was different, as the U.S.'s number of Olympic berths would be determined by skaters' performances at the 1993 World Championships. At these critical national championships, Kwiatkowski stood fourth after the short program. When Tonya Harding, reaching the nadir of a two-year skating slump, fell several times in her long program (after having placed second in the short program, during which her dress had come undone), and third-place Nicole Bobek also made several mistakes, fourth-place Kwiatkowski had a chance to move up onto the podium and onto the World team. With a sub-par performance, she managed to move up to third, as Carol Heiss' other pupil Lisa Ervin rose from fifth to second.

Regardless, her third-place finish meant that she was on the World team and heading to the World Championships. However, she skated extremely poorly in the initial round, failing to even qualify for the main draw, leaving the U.S. with just two skaters in the ladies' event. After Ervin finished in 14th place, heavy favorite Nancy Kerrigan skated poorly and fell from first after the short program to fifth overall, leaving the U.S. with just two berths for 1994. While Kerrigan was the logical scapegoat for this outcome, some U.S. officials were rumored to harbor resentment against Kwiatkowski as well.

Kwiatkowski did not skate well at the 1994 Nationals and finished fifth, failing to qualify for an Olympic spot. According to an 11 February 1995 article in the Chicago Tribune, "After she placed fifth overall in the 1994 nationals last January, her coach, Carol Heiss, was being told by skating insiders that Kwiatkowski had no future in the sport."

1995 to 1998
After graduating from college the previous year, Kwiatkowski gave a strong performance at the 1995 U.S. Nationals, taking the lead after the short program and finishing third behind Nicole Bobek and Michelle Kwan, with a fall on a triple flip in the long program costing her a shot at the title (see 1995 Nationals review article written the following year, "Kwiatkowksi is no kid at U.S. Championships" AP News, January 17, 1996). But because of the Americans' performance at the 1994 Worlds, only two slots were available for American ladies figure skaters, leaving Kwiatkowski off the World team in 1995.

Placing second in the 1996 Nationals behind Kwan assured Kwiatkowski a spot on that year's team, and she placed 8th at the Worlds in a performance that included a full arsenal of triple jumps. Overshadowed by Kwan's gold medal performance, Kwiatkowski's finish was something of a redemption, as she delivered the elements under pressure.

In 1998, at age 26, Kwiatkowski was the "old lady" of figure skating, nine years older than rival Michelle Kwan and eleven years senior Tara Lipinski. A heavy favorite to vie for the third Olympic spot behind the two youngsters, she had hoped to close out her career with a trip to the Olympics, but finished 4th at the U.S. National Championships behind Nicole Bobek and did not make the Olympic team. However, she had a chance to end her career on a positive note. Due to an illness, Tara Lipinski withdrew from the 1998 World Championships following the Olympics, and Kwiatkowski skated in her place. At age 27, she had "the skate of her life" and placed 6th, her best finish in a major international competition.

Results
GP: Champions Series (Grand Prix)

title: Tonia Kwiatkowski


text:
Norbornadiene

Norbornadiene is an organic compound and a bicyclic hydrocarbon. Norbornadiene is of interest as a metal-binding ligand, whose complexes are useful for homogeneous catalysis. It has been intensively studied owing to its high reactivity and distinctive structural property of being a diene that cannot isomerize (isomers would be anti-Bredt alkenes). Norbornadiene is also a useful dienophile in Diels-Alder reactions.

Synthesis
Norbornadiene can be formed by a Diels-Alder reaction between cyclopentadiene and acetylene
 * [[Image:Norbornadiene synthesis.png|300px|left|Norbornadiene synthesis]]

Reactions
Quadricyclane, a valence isomer, can be obtained from norbornadiene by a photochemical reaction when assisted by a sensitizer such as acetophenone:

 * Synthesis of quadricyclane from norbornadiene.png

The norbornadiene-quadricyclane couple is of potential interest for solar energy storage when controlled release of the strain energy stored in quadricyclane back to norbornadiene is made possible.

Norbornadiene is reactive in cycloaddition reactions. Norbornadiene is also the starting material for the synthesis of diamantane and sumanene and it is used as an acetylene transfer agent for instance in reaction with 3,6-di-2-pyridyl-1,2,4,5-tetrazine.

As a ligand
Norbornadiene is a versatile ligand in organometallic chemistry, where it serves as a two-electron or four-electron donor. (Norbornadiene)molybdenum tetracarbonyl is used as a source of "Mo(CO)4", exploiting the lability of the diene ligand in this case. which is a useful source of "chromium tetracarbonyl," e.g. in reactions with phosphine ligands.

The norbornadiene analogue of cyclooctadiene rhodium chloride dimer has been used in homogeneous catalysis. Chiral, C2-symmetric dienes derived from norbornadiene have also been described.

title: Norbornadiene


text:
User talk:DaemonSaber

Welcome!

Hello,, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are a few good links for newcomers: I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~); this will automatically produce your name and the date. If you need help, check out Where to ask a question, ask me on my talk page, or place  on your talk page and someone will show up shortly to answer your questions. Again, welcome! D. J. Bracey (talk) 22:02, 22 August 2005 (UTC)
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title: User talk:DaemonSaber