title: Cocoon (film)

text: About 10,000 years ago, peaceful aliens from the planet Antarea set up an outpost on Earth on Atlantis. When Atlantis sank, twenty aliens were left behind, kept alive in large rock-like cocoons at the bottom of the ocean. A group of Antareans have returned to collect them. Disguising themselves as humans, they rent a house with a swimming pool and charge the water with "life force" to give the cocooned Antareans energy to survive the trip home. They charter a boat from a local captain named Jack, who helps them retrieve the cocoons. Jack spies on Kitty, a beautiful woman from the team who chartered his boat, while she undresses in her cabin, and discovers that she is an alien. After the aliens reveal themselves to him and explain what is going on, he decides to help them.


title: Cocoon (film)

text: Next door to the house the Antareans are renting is a retirement home. Three of its residents, Ben, Arthur, and Joe, often trespass to swim in the pool. They absorb some of the life force, making them feel younger and stronger. Eventually caught in the act, they are given permission to use the pool by the Antarean leader, Walter, on the condition that they do not touch the cocoons or tell anybody else about it. Rejuvenated with youthful energy, the three men let the advantages of the pool take hold as they are relieved of their ailments.


title: Cocoon (film)

text: Kitty and Jack grow closer and decide to make love in the pool. Since she cannot do so in the human manner, she introduces him to the Antarean equivalent, in which she shares her life force energy with him.


title: Cocoon (film)

text: The other retirement home residents become suspicious after witnessing Ben's wife Mary climb a tree. Their friend Bernie reveals the secret of the pool to the other residents, who rush to the pool to swim in its waters. When Walter finds them damaging one of the cocoons, he ejects them from the property. The Antereans open the damaged cocoon, and the creature inside shares his last moments with Walter. That evening, Bernie finds his wife Rose has stopped breathing and carries her body to the pool to heal her, only to be informed by Walter that the pool no longer works due to the other residents draining the life force in the rush to make themselves young.


title: Cocoon (film)

text: Walter explains that the cocoons cannot survive the trip back to Antarea, but will be able to survive on Earth. With the help of Jack, Ben, Arthur and Joe, the Antareans return the cocoons to the sea. The Antareans offer to take residents of the retirement home with them to Antarea, where they will never grow older and never die. Most of them accept the offer, but Bernie chooses to remain on Earth.


title: Cocoon (film)

text: Upon leaving, Ben tells his grandson David that he and Mary are leaving for good. As the residents are leaving, David's mother Susan finds out about their destination and drives to the retirement home, where they find the majority of the rooms vacant and contact local authorities.


title: Cocoon (film)

text: While the police are searching for the residents, David notices Jack's boat, with the Antareans and the retirement residents aboard, starting and jumps onto the side as it pulls away. The boat is chased by the Coast Guard, so with little time left, David says goodbye to Ben and Mary before jumping into the water. The Coast Guard boats stop to pick him up, giving the others a chance to get away. A thick fog appears and strands the remaining Coast Guard boats, and they call off the chase.


title: Cocoon (film)

text: As the Antarean ship appears, Walter pays Jack for his services and the boat. Jack embraces Kitty for the last time and they share a kiss. He then says farewell to everyone before jumping into an inflatable raft as the boat rises up into the Antarean vessel. Jack watches as the boat disappears inside the ship and departs.


title: Cocoon (film)

text: Back on earth, a funeral is held for the missing residents. During the sermon, David looks toward the sky and smiles.


title: Cocoon (film)

text: Robert Zemeckis was originally hired as director, and spent a year working on it in development. He was at the time directing "Romancing the Stone", another film for the same studio, 20th Century Fox. Fox executives previewed "Romancing the Stone" before its release in 1984 and hated it. That, in addition to his two previous directorial efforts, "I Wanna Hold Your Hand" and "Used Cars", both being commercial failures (though critically acclaimed) led the studio to fire Zemeckis as director of "Cocoon". He was replaced with Ron Howard.


title: Cocoon (film)

text: Wilford Brimley was only 49 when he was cast as a senior citizen, and turned 50 during filming; he was as much as 26 years younger than the actors playing the other elderly characters. In order to look the part, Brimley bleached his hair and moustache to turn them gray, and had wrinkles and liver spots drawn on his face.


title: Cocoon (film)

text: The score for "Cocoon" was composed and conducted by James Horner. The soundtrack was released twice, through Polydor Records in 1985 and a reprint through P.E.G. in 1997 and features eleven tracks of score and a vocal track performed by Michael Sembello. Despite the reprint, it is still considered a rarity among soundtrack collectors.


title: Cocoon (film)

text: The film received mostly positive critical reception. Commented "The New York Times"' Janet Maslin, "Mr. Howard brings a real sweetness to his subject, as does the film's fine cast of veteran stars; he has also given "Cocoon" the bright, expansive look of a hot-weather hit. And even when the film begins to falter, as it does in its latter sections, Mr. Howard's touch remains reasonably steady. He does the most he can with material that, after an immensely promising opening, heads into the predictable territory of Spielberg-inspired beatific science fiction." "Variety" called it "a fountain of youth fable which imaginatively melds galaxy fantasy with the lives of aging mortals in a Florida retirement home [and] weaves a mesmerizing tale."


title: Cocoon (film)

text: The film holds a 76% "Fresh" rating on Rotten Tomatoes from 33 critics. The critical consensus reads, "Though it may be too sentimental for some, Ron Howard's supernatural tale of eternal youth is gentle and heartwarming, touching on poignant issues of age in the process." Metacritic gave the film a score of 65 based on 18 reviews, indicating "generally favorable reviews".


title: Cocoon (film)

text: The film was also a box office hit, making over $76 million in North America where it became the sixth highest-grossing film of 1985.


title: Where's Wally?

text: Where's Wally? (called Where's Waldo? in North America) is a British series of children's puzzle books created by English illustrator Martin Handford. The books consist of a series of detailed double-page spread illustrations depicting dozens or more people doing a variety of amusing things at a given location. Readers are challenged to find a character named Wally hidden in the group.


title: Where's Wally?

text: Wally is identified by his red-and-white-striped shirt, bobble hat, and glasses, but many illustrations contain red herrings involving deceptive use of red-and-white striped objects. Later entries in the long-running book series added other targets for readers to find in each illustration. The books have also inspired two television programmes ("Where's Wally?" the 1991 animated series and "Where's Wally?" the 2019 animated series), a comic strip and a series of video games.


title: Where's Wally?

text: , more than 73 million books of "Where's Wally?" (and his regional names) had been sold around the world since his original publication in 1987. The series of pictorial puzzle books has been translated into 26 languages, and is published in over 50 countries.


title: Where's Wally?

text: In 1986, illustrator Martin Handford, a graduate of the University for the Creative Arts in Kent, was asked by his art director, David Bennett, at Walker Books in London to develop a book of detailed crowd scenes, inspired by Bennett having seen Philippe Dupasquier's "Busy Places" series. Whilst the book was being prepared for Bologna Book Fair, someone at Walker Books suggested the idea of adding a distinctive-looking character whom the reader could search for in the crowd scenes. After much thinking, Handford came up with the idea of "Wally", a world traveller and time travel aficionado who always dresses in red and white. Sometimes it would take him up to eight weeks to draw a two-page sketch of the elusive "Wally" and the characters surrounding him.


title: Where's Wally?

text: The first "Where's Wally?" book was published on 21 September 1987. "Where's Wally?" books were published in the United Kingdom by Walker Books and in the United States under the title "Where's Waldo?" first by Little, Brown and Company before being taken on by Candlewick Press (Walker Books' American subsidiary publishing company). The first four titles were originally printed in Italy, but later reprinted in China.


title: Where's Wally?

text: The books became extremely popular and were localised for many different territories, with name changes for Wally in certain regions. The franchise also spawned other media in a more storyline-based form, including a 1991 television series, "Where's Wally?", a comic strip, "Where's Wally?" and a series of video games.


title: Where's Wally?

text: As the series goes on, Wally progressively becomes harder to find, reducing his size on the page and surrounding him by more characters. In the first book, Wally was on average big. This was reduced to in the second book, in the third, and between in the fourth through seventh books. He has also been surrounded by more characters, from 225 on the first book's first page to about 850 on the last book's first page.


title: Where's Wally?

text: , there are seven primary Wally books. The books were released both in hard-cover (for the original books) and subsequently in paperback. Each contains around a dozen scenes with Wally hidden in them. Each book has additional hidden objects and/or characters hidden in each scene specific to that book. The books usually reserve telling the reader about some item(s) to find until the end of the book so that the reader will have to go through the book again. The books contain checklists for each scene of interesting things or people to find.


title: Where's Wally?

text: There have been three rounds of revised editions. In 1993, to coincide with the publication of "In Hollywood", the first three books were reprinted with Wenda, Woof and the Wally Watchers added to the original illustrations, and the books were numbered on the cover. A "pocket edition" of the first book was also published, in a tiny A6 format (). Wally is even harder to spot when shrunk to this degree, and later printings included a free magnifying lens.


title: Where's Wally?

text: In 1997, to coincide with the publication of "The Wonder Book", special "Tenth Anniversary Editions" of the first four books were published with a distinct silver border on their front covers, and added later-introduced characters and objects to look for in every scene, and also moved Wally to different locations from the original versions. These special editions appeared in both standard and "pocket" formats.


title: Where's Wally?

text: In 2007, for the 20th anniversary of the first book, the special editions of 1997 (and "The Great Picture Hunt") were re-released with a new cover into paperback format. The silver borders on the books were removed and instead, the books were numbered in the top left-hand corner of the cover. Aside from the new numbering system, some of the front covers were also revised otherwise; for example, the "NOW?" on the cover of "Where's Wally Now?" was given a 2D effect, but it was originally designed to look like a 3D shape.


title: Where's Wally?

text: In addition to the primary books, other books have also been published in the Wally franchise. The first alternate-format Wally book was the "Ultimate Fun Book". In addition to standard Wally scenes, this paperback activity book featured other types of games and activities, as well as cardboard punch-outs and stickers. "The Magnificent Poster Book", which was a large-format book of posters including five scenes from past books and six new scenes (later included in "The Great Picture Hunt").


title: Where's Wally?

text: Several other "activity books" have also been published featuring art from the "Where's Wally" comic strip:


title: Where's Wally?

text: The first six activity books mentioned were reprinted in 2009 in a smaller size with different packaging.


title: Where's Wally?

text: A series of geographical magazines for children was published in the United Kingdom, Ukraine, Ireland, Australia, New Zealand, South Africa, Portugal, Poland, Brazil, Spain, France, Hungary, Czech Republic, Malta, Bulgaria and Russia, called "Wally's World". In each issue Wally travelled to a different country or region of the world giving the reader interesting facts. 52 issues were published from January 1997 to January 1998, when "Wally's History of the World" began, focusing more on history than geography. The first issue was given away free with the last issue of "Wally's World".


title: Where's Wally?

text: A 13-episode animated series, "Where's Wally?", with Townsend Coleman as the voice of Wally, was produced by DiC for CBS in 1991 for the North American market under the "Waldo" name. The show was later translated for international markets – usually renaming the character to match the books of that country. The dialogue and theme song were recorded in alternative "Wally" versions, with the same voice cast of the original US production, in order to market the show in the UK. It was aired on ITV in the UK and the distribution rights to the show are currently held by HIT Entertainment.


title: Where's Wally?

text: A new animated series by DreamWorks Animation Television aired on Universal Kids in 2019. The voice cast includes Joshua Rush as the voice of Waldo, Haley Tju as Wenda, Eva Carlton as Odlulu (the female equivalent to Odlaw), Thomas Lennon as Wizard Whitebeard and Ian James Corlett as Woof. The series later moved to Peacock.


title: Where's Wally?

text: A film based on the "Where's Wally?" series of books has been pursued by various studios. Nickelodeon was the one of the studios to take an interest in the idea but when the regime at Paramount (Nickelodeon's corporate sister) changed, the project was cancelled. In June 2009, Universal Studios (who would later obtain ownership of the property through its acquisition of Classic Media's owner DreamWorks Animation in 2016) and Illumination Entertainment had acquired the rights to turn "Where's Wally?" into a live-action film, but the project was also cancelled.


title: Where's Wally?

text: In November 2011, Metro-Goldwyn-Mayer and Classic Media announced a live-action film based on the "Where's Wally?" series. Screenwriter Todd Berger has been hired to write the story for the film, which was slated to be released in the summer of 2015. In March 2016, Seth Rogen and Evan Goldberg were in talks to produce the film with their producing partner James Weaver and Kyle Hunter and Ariel Shaffir to write the film, under their Point Grey Pictures banner.


title: Where's Wally?

text: The 1994 comedy film "", starring Leslie Nielsen and Priscilla Presley, features a cameo appearance by Wally at the end of the film during a scene that takes place at the Academy Awards.


title: Where's Wally?

text: During the 2012 Super Bowl, Wally was featured in a MetLife commercial. As in the series, Wally was hard to find in the commercial.


title: Where's Wally?

text: For several years in the early and mid-1990s, "Where's Wally?" was turned into a Sunday newspaper comic/puzzle, distributed by King Features Syndicate. The strip was later translated and reworked for international markets, including releases in book form in the US, using the regional name 'Waldo'.


title: Where's Wally?

text: In the early 1990s Quaker Life Cereal in the US carried various "Where's Waldo?" scenes on the back of the boxes along with collector's cards, toys and send-away prizes.


title: Where's Wally?

text: This was shown in "The Simpsons" episode "Hello Gutter, Hello Fadder" where Homer shouts "Waldo, where are you?!" after looking at the scene on the cereal box as Waldo walks by the kitchen window.


title: Where's Wally?

text: On 1 April 2018, Google Maps added a minigame in which one can look for Wally and his friends around the world – in the Andes (Chile), Surfers Paradise beach (Australia), in the Pyeongchang Olympic Stadium (South Korea), at the La Tomatina festival (Spain), in Hollywood and in the Picard crater on the Moon.


title: Where's Wally?

text: In 2009, 1,052 students, alumni, and members of the community at Rutgers University in New Brunswick, New Jersey, captured the "Guinness World Record" for the largest gathering of people dressed as Wally. The event raised money for local public schools.


title: Where's Wally?

text: In 2011, the previous record was broken when 3,872 people dressed as Wally gathered in Merrion Square, Dublin, Ireland.


title: Where's Wally?

text: The record was beaten in 2017 when 4,626 people dressed as Wally gathered in Japan, after three failed attempts.


title: Where's Wally?

text: The Waldo Waldo 5K has tried to break the record in a 5-kilometre fun run to raise money for the Waldo Canyon Fire burn area in Colorado Springs, Colorado, US, every year since the fire in July 2012. The first attempt, on 21 October, had just over a thousand. The second attempt, on 27 October 2013, had over 2,700. The third attempt, on 26 October 2014, hosted 3,104 participants. The fourth attempt, on 17 October 2015, increased the count to 3,400 participants. The fifth attempt was made on 22 October 2016, with a final count of 3,524. The next race was held on 21 October 2017.


title: Where's Wally?

text: On 12 September 2009, a re-creation took place in downtown Chicago. The re-creation featured all of the characters, Wally, Wenda, Wizard Whitebeard, Odlaw, and Woof, hiding throughout downtown Chicago and invited others to come and find them.


title: Where's Wally?

text: Universities (such as the University of Exeter) have had Where's Wally inspired societies, in which members may dress as Wally whilst playing games such as hide-and-seek on campus grounds.


title: Wallonia

text: Wallonia (; ), officially the Walloon Region (), is one of the three regions of Belgium—along with Flanders and Brussels. Covering the southern portion of the country, Wallonia is primarily French-speaking. It accounts for 55% of Belgium's territory, but only a third of its population. The Walloon Region and the French Community of Belgium, which is the political entity responsible for matters related mainly to culture and education, are independent concepts, because the French Community of Belgium encompasses both Wallonia and the bilingual Brussels-Capital Region.


title: Wallonia

text: There is a German-speaking minority in eastern Wallonia, resulting from the annexation of three cantons previously part of the German Empire at the conclusion of World War I. This community represents less than 1% of the Belgian population. It forms the German-speaking Community of Belgium, which has its own government and parliament for culture-related issues.


title: Wallonia

text: During the industrial revolution, Wallonia was second only to the United Kingdom in industrialization, capitalizing on its extensive deposits of coal and iron. This brought the region wealth, and from the beginning of the 19th to the middle of the 20th century, Wallonia was the more prosperous half of Belgium. Since World War II, the importance of heavy industry has greatly diminished, and the Flemish Region has exceeded Wallonia in wealth as Wallonia has declined economically. Wallonia now suffers from high unemployment and has a significantly lower GDP per capita than Flanders. The economic inequalities and linguistic divide between the two are major sources of political conflicts in Belgium and a major factor in Flemish separatism.


title: Wallonia

text: The capital of Wallonia is Namur, and the most populous city is Charleroi. Most of Wallonia's major cities and two-thirds of its population lie along the east–west aligned Sambre and Meuse valley, the former industrial backbone of Belgium. To the north of this valley, Wallonia lies on the Central Belgian Plateau, which, like Flanders, is a relatively flat and agriculturally fertile area. The south and southeast of Wallonia is made up of the Ardennes, an expanse of forested highland that is less densely populated.


title: Wallonia

text: Wallonia borders Flanders and the Netherlands (the province of Limburg) in the north, France (Grand Est and Hauts-de-France) to the south and west, and Germany (North Rhine-Westphalia and Rhineland-Palatinate) and Luxembourg (Capellen, Clervaux, Esch-sur-Alzette, Redange and Wiltz) to the east. Wallonia has been a member of the Organisation Internationale de la Francophonie since 1980.


title: Wallonia

text: The term "Wallonia" can mean slightly different things in different contexts. One of the three federal regions of Belgium is still constitutionally defined as the "Walloon Region" as opposed to "Wallonia", but the regional government has renamed itself Wallonia, and it is commonly called Wallonia. Preceding 1 April 2010, when the renaming came into effect, Wallonia would sometimes refer to the territory governed by the Walloon Region, whereas "Walloon Region" referred specifically to the government. In practice, the difference between the two terms is small and what is meant is usually clear, based on context.


title: Wallonia

text: Wallonia is a cognate of terms such as Wales, Cornwall and Wallachia, ultimately also related to words Celt and Belgae, phonetically evolved over centuries. The Germanic word Walha, meaning "the strangers", referred to Gallic or Celtic people. Wallonia is named after the Walloons, a group of locals who natively speak Romance languages. In Middle Dutch (and French), the term Walloons included both historical secular Walloon principalities, as well as the French-speaking population of the Prince-Bishopric of Liège or the whole population of the Romanic sprachraum within the medieval Low Countries.


title: Wallonia

text: Julius Caesar conquered Gaul in 57 BC. The Low Countries became part of the larger Gallia Belgica province which originally stretched from southwestern Germany to Normandy and the southern part of the Netherlands. The population of this territory was Celtic with a Germanic influence which was stronger in the north than in the south of the province. Gallia Belgica became progressively romanized. The ancestors of the Walloons became Gallo-Romans and were called the "Walha" by their Germanic neighbours. The "Walha" abandoned their Celtic dialects and started to speak Vulgar Latin.


title: Wallonia

text: The Merovingian Franks gradually gained control of the region during the 5th century, under Clovis. Due to the fragmentation of the former Roman Empire, Vulgar Latin regionally developed along different lines and evolved into several "langue d'oïl" dialects, which in Wallonia became Picard, Walloon and Lorrain. The oldest surviving text written in a "langue d'oïl", the "Sequence of Saint Eulalia", has characteristics of these three languages and was likely written in or very near to what is now Wallonia around 880 AD. From the 4th to the 7th century, the Franks established several settlements, probably mostly in the north of the province where the romanization was less advanced and some Germanic trace was still present. The language border (that now splits Belgium in the middle) began to crystallize between 700 under the reign of the Merovingians and Carolingians and around 1000 after the Ottonian Renaissance. French-speaking cities, with Liège as the largest one, appeared along the Meuse, while Gallo-Roman cities such as Tongeren, Maastricht and Aachen became Germanized.


title: Wallonia

text: The Carolingian dynasty dethroned the Merovingians in the 8th century. In 843, the Treaty of Verdun gave the territory of present-day Wallonia to Middle Francia, which would shortly fragment, with the region passing to Lotharingia. On Lotharingia's breakup in 959, the present-day territory of Belgium became part of Lower Lotharingia, which then fragmented into rival principalities and duchies by 1190. Literary Latin, which was taught in schools, lost its hegemony during the 13th century and was replaced by Old French.


title: Wallonia

text: In the 15th century, the Dukes of Burgundy took over the Low Countries. The death of Charles the Bold in 1477 raised the issue of succession, and the Liégeois took advantage of this to regain some of their autonomy. From the 16th to the 18th century, the Low Countries were governed successively by the Habsburg dynasty of Spain (from the early 16th century until 1713–14) and later by Austria (until 1794). This territory was enlarged in 1521–22 when Charles V, Holy Roman Emperor gained the Tournai region from France.


title: Wallonia

text: Present-day Belgium was conquered in 1795 by the French Republic during the French Revolutionary Wars. It was annexed to the Republic, which later became the Napoleonic Empire. After the Battle of Waterloo, Wallonia became part of the Kingdom of the Netherlands under King William of Orange. The Walloons played an active part in the Belgian Revolution in 1830. The Provisional Government of Belgium proclaimed Belgium's independence and held elections for the National Congress.


title: Wallonia

text: In the 19th century, the area began to industrialize, and Wallonia was the first fully industrialized area in continental Europe. This brought the region great economic prosperity, which was not mirrored in poorer Flanders and the result was a large amount of Flemish immigration to Wallonia. Belgium was divided into two divergent communities. On the one hand, the very Catholic Flemish society was characterized by an economy centered on agriculture; on the other hand, Wallonia was the center of the continental European Industrial Revolution, where classical liberal and socialist movements were rapidly emerging. Major strikes and general strikes took place in Wallonia, including the Walloon jacquerie of 1886, the Belgian general strikes of 1893, 1902, 1913 (for universal suffrage), 1932 (depicted in "Misère au Borinage"), and 1936. After World War II, major strikes included the general strike against Leopold III of Belgium (1950), and the 1960-1961 Winter General Strike for autonomy for Wallonia.


title: Wallonia

text: The profitability of the heavy industries to which Wallonia owed its prosperity started declining in the first half of the 20th century, and the center of industrial activity shifted north to Flanders. The loss of prosperity caused social unrest, and Wallonia sought greater autonomy in order to address its economic problems. In the wake of the 1960-1961 Winter General Strike, the process of state reform in Belgium got underway. This reform started partly with the linguistic laws of 1962–63, which defined the four language areas within the constitution. But the strikes of 1960 which took place in Wallonia more than in Flanders are not principally linked with the four language areas nor with the Communities but with the Regions. In 1968, the conflict between the communities burst out. French speakers in Flanders (who were not necessarily Walloons) were driven out of, most notably the Leuven-based Catholic University amid shouts of ""Walen buiten"!" ("Walloons out!"). After a formal split of the university in two and the creation of a brand new campus in Wallonia, a wider series of State reforms was passed in Belgium, which resulted in the federalisation of the nation and the creation of the Walloon Region and the French Community (comprising both Wallonia and Brussels), administrative entities each of which would gain various levels of considerable autonomy.


title: Wallonia

text: Wallonia is landlocked, with an area of , or 55 percent of the total area of Belgium. The Sambre and Meuse valley, from Liège () to Charleroi () is an entrenched river in a fault line which separates Middle Belgium (elevation ) and High Belgium (). This fault line corresponds to a part of the southern coast of the late London-Brabant Massif. The valley, along with Haine and Vesdre valleys form the "sillon industriel", the historical centre of the Belgian coalmining and steelmaking industry, and is also called the Walloon industrial backbone. Due to their long industrial historic record, several segments of the valley have received specific names: Borinage, around Mons, le Centre, around La Louvière, the Pays noir, around Charleroi and the Basse-Sambre, near Namur.


title: Wallonia

text: To the north of the Sambre and Meuse valley lies the Central Belgian plateau, which is characterized by intensive agriculture. The Walloon part of this plateau is traditionally divided into several regions: Walloon Brabant around Nivelles, Western Hainaut (, around Tournai), and Hesbaye around Waremme. South of the sillon industriel, the land is more rugged and is characterized by more extensive farming. It is traditionally divided into the regions of Entre-Sambre-et-Meuse, Condroz, Fagne-Famenne, the Ardennes and Land of Herve, as well as the Belgian Lorraine around Arlon and Virton. Dividing it into Condroz, Famenne, Calestienne, Ardennes (including Thiérache), and Belgian Lorraine (which includes the Gaume) is more reflective of the physical geography. The larger region, the Ardennes, is a thickly forested plateau with caves and small gorges. It is host to much of Belgium's wildlife but little agricultural capacity. This area extends westward into France and eastward to the Eifel in Germany via the High Fens plateau, on which the Signal de Botrange forms the highest point in Belgium at 694 metres (2,277 ft).


title: Wallonia

text: The Walloon region covers and is divided into five provinces, 20 arrondissements and 262 cities or municipalities.


title: Wallonia

text: The province of Walloon Brabant is the most recent one, being formed in 1995 after the splitting of the province of Brabant.


title: Wallonia

text: Contributions to the development of science and technology have appeared since the beginning of the country's history. The baptismal font of Renier de Huy is not the only example of medieval Walloon technical expertise: the words "houille" (coal) or "houilleur" (coal miner) or "grisou" (damp) were coined in Wallonia and are Walloon in origin.


title: Wallonia

text: The economically important very deep coal mining in the course of the First Industrial Revolution has required highly reputed specialized studies for mining engineers. But that was already the case before the Industrial Revolution, with an engineer as Rennequin Sualem for instance.


title: Wallonia

text: Engineer Zenobe Gramme invented the Gramme dynamo, the first generator to produce power on a commercial scale for industry. Chemist Ernest Solvay gave his name to the Solvay process for production of soda ash, an important chemical for many industrial uses. Ernest Solvay also acted as a major philanthropist and gave its name to the Solvay Institute of Sociology, the Solvay Brussels School of Economics and Management and the International Solvay Institutes for Physics and Chemistry which are now part of the Université libre de Bruxelles. In 1911, he started a series of conferences, the Solvay Conferences on Physics and Chemistry, which have had a deep impact on the evolution of quantum physics and chemistry.


title: Wallonia

text: Georges Lemaître of the Université catholique de Louvain is credited with proposing the Big Bang theory of the origin of the universe in 1927.


title: Wallonia

text: Three Nobel Prizes in Physiology or Medicine were awarded to Walloons: Jules Bordet (Université libre de Bruxelles) in 1919, Albert Claude (ULB) together with Christian De Duve (UCLouvain) in 1974.


title: Wallonia

text: In the present day, Bureau Greisch has acquired an international reputation as consulting engineer and architect in the fields of structures, civil engineering and buildings, including the Millau Viaduct in France.


title: Wallonia

text: Wallonia is rich in iron and coal, and these resources and related industries have played an important role in its history. In ancient times, the Sambre and Meuse valley was an important industrial area in the Roman Empire. In the Middle Ages, Wallonia became a center for brass working and bronze working, with Huy, Dinant and Chimay being important regional centers. In the 12th and 13th centuries, the iron masters of Liège developed a method of refining iron ore by the use of a blast furnace, called the Walloon Method. There were also a few coal mines around Charleroi and the Borinage during this period, but their output was small, and was principally consumed as fuel by various industries such as the important glassmaking industry that sprang up in the Charleroi basin during the 14th century.


title: Wallonia

text: In the 19th century, the area began to industrialize, mainly along the so-called sillon industriel. It was the first fully industrialized area in continental Europe, and Wallonia was the second industrial power in the world, in proportion to its population and its territory, after the United Kingdom. The sole industrial centre in Belgium outside the collieries and blast furnaces of Wallonia was the historic cloth making town of Ghent.


title: Wallonia

text: The two World Wars curbed the continuous expansion that Wallonia had enjoyed up till that time. Towards the end of the 1950s, things began to change dramatically. The factories of Wallonia were by then antiquated, the coal was running out and the cost of extracting coal was constantly rising. It was the end of an era, and Wallonia has been making efforts to redefine itself. The restoration of economical development is high on the political agenda, and the government is encouraging development of industries, notably in cutting-edge technology and in business parks. The economy is improving, but Wallonia is not yet at the level of Flanders and is still suffering from difficulties.


title: Wallonia

text: The current Walloon economy is relatively diversified, although certain areas (especially around Charleroi and Liège) are still suffering from the steel industry crisis, with an unemployment rate of up to 30 percent. Nonetheless, Wallonia has some companies which are world leaders in their specialized fields, including armaments, glass production, lime and limestone production, cyclotrons and aviation parts. The south of Wallonia, bordering Luxembourg, benefits from its neighbour's economic prosperity, with many Belgians working on the other side of the border; they are often called "frontaliers". The Ardennes area south of the Meuse is a popular tourist destination for its nature and outdoor sports, in addition to its cultural heritage, with places such as Bastogne, Dinant, Durbuy, and the famous hot springs of Spa.


title: Wallonia

text: The Gross domestic product (GDP) of the region was 105.7 billion € in 2018, accounting for 23% of Belgian economic output. GDP per capita adjusted for purchasing power was 25,700 € or 85% of the EU27 average in the same year.


title: Wallonia

text: Belgium is a federal state made up of three communities and three regions, each with considerable autonomy. One of these is the Walloon Region, which is governed by the Parliament of Wallonia and the executive Government of Wallonia. The Walloon Region's autonomy extends even to foreign policy; Wallonia is entitled to pursue its own foreign policy, including the signing of treaties, and in many domains, even the Belgian federal government is not able to sign an international treaty without the agreement of the Parliament of Wallonia.


title: Wallonia

text: Wallonia is also home to about 80 percent of the population of the French Community of Belgium, a political level responsible for matters related mainly to culture and education, with the remainder living in Brussels. Wallonia is also home to the small German-speaking Community of Belgium in the east, which has its own government and parliament for culture-related issues. Although in Flanders, the Flemish Region assigned all of its powers to the Flemish Community, the Walloon Region remains in principle distinct from and independent from the French Community, and vice versa. Despite this, the French Community's parliament is almost entirely composed of members of Wallonia's and Brussels' parliaments, so the bodies are governed by the same individuals. Additionally, the French Community of Belgium has controversially begun referring to itself exclusively as the 'Wallonia-Brussels Federation' to emphasize the links between the French Community, Wallonia and Brussels.


title: Wallonia

text: The Walloon Region has a unicameral parliament with 75 members elected for five years by direct universal suffrage, and an executive, the Government of Wallonia, elected by a political majority in Parliament. The Government numbers nine members with the president. Each member is called a "Walloon minister". The head of the Government is called the Minister-President of Wallonia. The coalition government for the 2014–2019 legislature was a center-left coalition PS-cdH until July 28 when it was replaced by a center-left coalition MR-cdH. The current Minister-President is Elio Di Rupo.


title: Wallonia

text: "From 1831, the year of Belgium's independence, until the federalization of the country in 1970, Wallonia has increasingly asserted itself as a region in its own right." Following several state reforms, especially the 1993 state reform, Belgium became a federal state made up of three communities and three regions, with Wallonia being represented by the Walloon Region and its two language communities. The directly elected Walloon Parliament was created in June 1995, replacing the "Conseil régional wallon" (Regional Council of Wallonia). The first Council had sat on 15 October 1980 and was composed of members of the Belgian Chamber of Representatives and the Belgian Senate elected in Wallonia.


title: Wallonia

text: The first appearance of the French word "Wallonie" as a reference to the romance world as opposed to Germany is said to date from 1842. Two years later, it was first used to refer to the Romance part of the young country of Belgium. In 1886, the writer and Walloon militant Albert Mockel, first used the word with a political meaning of cultural and regional affirmation, in opposition with the word "Flanders" used by the Flemish Movement. The word had previously appeared in German and Latin as early as the 17th century.


title: Wallonia

text: The rising of a Walloon identity led the Walloon Movement to choose different symbols representing Wallonia. The main symbol is the "bold rooster" (), also named "Walloon rooster" (, ), which is widely used, particularly on arms and flags. The rooster was chosen as an emblem by the Walloon Assembly on 20 April 1913, and designed by Pierre Paulus on 3 July 1913. The Flag of Wallonia features the red rooster on a yellow background.


title: Wallonia

text: An anthem, ("The Walloons' Song"), written by Theophile Bovy in 1900 and composed by Louis Hillier in 1901, was also adopted. On September 21, 1913, the "national" feast day of Wallonia took place for the first time in Verviers, commemorating the participation of Walloons during the Belgian Revolution of 1830. It is held annually on the third Sunday of September. The Assembly also chose a motto for Wallonia, "Walloon Forever" (), and a cry, "Liberty" (). In 1998, the Walloon Parliament made all these symbols official except the motto and the cry.


title: Wallonia

text: The population of Wallonia is predominantly of Christian heritage. In 2016, 68% of residents of Wallonia declared themselves to be Roman Catholic (21% were practising Catholics and 47% were non-practising), 3% were Muslim, 3% were Protestant Christian, 1% were of other religions and 25% were non-religious.


title: Wallonia

text: French is by far the main language of Wallonia and holds official status; in the East Cantons, German is also official. The German-speaking Community of Belgium accounts for about 2% of the region's population. Belgian French, which is also spoken in the Brussels-Capital Region, is similar to that spoken in France, with slight differences in pronunciation and some vocabulary differences, notably the use of the words "septante" (70) and "nonante" (90), as opposed to "soixante-dix" and "quatre-vingt-dix" in France.


title: Wallonia

text: There are noticeable Walloon accents, with the accent from Liège and its surroundings being perhaps the most striking. Other regions of Wallonia also have characteristic accents, often linked to the regional language.


title: Wallonia

text: Walloons traditionally also speak regional Romance languages, all from the "Langues d'oïl" group. Wallonia includes almost all of the area where Walloon is spoken, a Picard zone corresponding to the major part of the Hainaut Province, the Gaume (district of Virton) with the Lorrain language and a Champenois zone. There are also regional Germanic languages, such as the Luxembourgish language in Arelerland (Land of Arlon). The regional languages of Wallonia are more important than in France, and they have been officially recognized by the government. With the development of education in French, however, these dialects have been in continual decline. There is currently an effort to revive Walloon dialects; some schools offer language courses in Walloon, and Walloon is also spoken in some radio programmes, but this effort remains very limited.


title: Wallonia

text: Literature is written principally in French but also in Walloon and other regional languages, colloquially called Walloon literature. Walloon literature (regional language not French) has been printed since the 16th century. But it did have its golden age, paradoxically, during the peak of the Flemish immigration to Wallonia in the 19th century: "That period saw an efflorescence of Walloon literature, plays and poems primarily, and the founding of many theaters and periodicals." The New York Public Library possesses a surprisingly large collection of literary works in Walloon, quite possibly the largest outside Belgium, and its holding are representative of the output. Out of nearly a thousand, twenty-six were published before 1880. Thereafter the numbers rise gradually year by year, reaching a peak of sixty-nine in 1903, and then they fall again, down to eleven in 1913. See 'Switching Languages', p. 153. Yves Quairiaux counted 4800 plays for 1860–1914, published or not. In this period plays were almost the only popular show in Wallonia. But this theater remains popular in the present-day Wallonia: Theater is still flourishing, with over 200 non-professional companies playing in the cities and villages of Wallonia for an audience of over 200,000 each year. There are links between French literature and (the very small) Walloon literature. For instance Raymond Queneau set Editions Gallimard the publication of a Walloon Poets' anthology. Ubu roi was translated in Walloon by André Blavier ( an important pataphysician of Verviers, friend of Queneau), for the new and important Puppets theater of Liège of Jacques Ancion, the Al Botroûle theater "at the umbilical cord" in Walloon indicating a desire to return to the source (according to Joan Cross). But Jacques Ancion wanted to develop a regular adult audience. From the 19th century, he included the Walloon play "Tati l'Pèriquî" by E.Remouchamps and the avant-garde "Ubu roi" by A.Jarry. For Jean-Marie Klinkenberg, "the dialectal culture is no more a sign of attachment to the past but a way to participate to a new synthesis".


title: Wallonia

text: Jean-Marie Klinkenberg (member of the Groupe µ) wrote that Wallonia, and literature in Wallonia, has been present in French language since its formation. In their 'Histoire illustrée des lettres française de Belgique', Charlier and Hanse (editors), La Renaissance du livre, Bruxelles, 1958, published 247 pages (on 655 ), about the "French" literature in the Walloon provinces (or Walloon principalities of the Middle-Age, sometimes also Flemish provinces and principalities), for a period from the 11th to the 18th century. Among the works or the authors, the Sequence of Saint Eulalia (9th century), La Vie de Saint Léger (10th century), Jean Froissart (14th century in the County of Hainaut), Jean d'Outremeuse, Jean Lebel, Jean Lemaire de Belges (16th century from Bavay), the Prince of Ligne (18th century, Beloeil). There is a Walloon Surrealism, especially in Hainaut Province. Charles Plisnier (1896–1952), born in Mons, won the Prix Goncourt in 1936, for his novel "Mariages" and for "Faux Passeports" (short stories denouncing Stalinism, in the same spirit as Arthur Koestler). He was the first foreigner to receive this honour. The Walloon Georges Simenon is likely the most widely read French-speaking writer in the world, according to the Tribune de Genève. More than 500 million of his books have been sold, and they have been translated into 55 languages. There is a link between the Jean Louvet's work and the social issues in Wallonia.


title: Wallonia

text: Picard is spoken in Hainaut Province of western Belgium. Notable Belgian authors who wrote in Picard include Géo Libbrecht, Paul Mahieu, Paul André, Francis Couvreur and Florian Duc.


title: Wallonia

text: Mosan art is a regional style of Romanesque art from the Meuse river valley in present-day Wallonia, and the Rhineland, with manuscript illumination, metalwork, and enamel work from the 11th, 12th and 13th centuries. Among them is the masterpiece of Renier de Huy and perhaps of the whole Mosan art Baptismal font at St Bartholomew's Church, Liège. The architecture of Roman churches of the Walloon country are also named mosan, exemplified by the Collegiate Church of Saint Gertrude in Nivelles, and the churches of Waha and Hastière, Dinant. The Ornamental brassware is also a part of the Mosan art and among these dinandiers Hugo d'Oignies and Nicholas of Verdun.


title: Wallonia

text: Flemish art was not confined to the boundaries of modern Flanders and several leading artists came from or worked in areas in which langues d'oïl were spoken, from the region of modern Wallonia, e.g. Robert Campin, Rogier van der Weyden (Rogier de la Pasture) and Jacques Daret. Joachim Patinir Henri Blès are generally called mosan painters. Lambert Lombard (Liège, 1505 – 1566) was a Renaissance painter, architect and theorist for the Prince-Bishopric of Liège. Gérard de Lairesse, Bertholet Flemalle were also important painters in the Prince-Bishopric of Liège.


title: Wallonia

text: Gustave Serrurier-Bovy (Liège, 1858 – Antwerp, 1910) architect and furniture designer, credited (along with Paul Hankar, Victor Horta and Henry van de Velde) with creating the Art Nouveau style, coined as a style in Paris by Bing. And in Liège also, principally Jean Del Cour, the sculptor of the Virgin in "Vinâve d'Isle", Léon Mignon the sculptor of "Li Tore" and Louis Jéhotte of the statue of Charlemagne.


title: Wallonia

text: George Grard (1901—1984) was a Walloon sculptor, known above all for his representations of the female, in the manner of Pierre Renoir and Aristide Maillol, modelled in clay or plaster, and cast in bronze.


title: Wallonia

text: During the 19th and 20th centuries many original romantic, expressionist and surrealist Wallon painters emerged, including Félicien Rops, Paul Delvaux, Pierre Paulus, Fernand Verhaegen, Antoine Wiertz, René Magritte ... The avant-garde CoBrA movement appeared in the 1950s.


title: Wallonia

text: There was an important musical life in Prince-Bishopric of Liège since the beginning. Between 1370 and 1468 flourished a school of music in Liège, with Johannes Brassart, Johannes de Sarto and firstly Johannes Ciconia, the third Master of Ars Nova.


title: Wallonia

text: The vocal music of the so-called Franco-Flemish School developed in the southern part of the Low Countries and was an important contribution to Renaissance culture. Robert Wangermée and Philippe Mercier wrote in their encyclopedic book about the Walloon music that Liège, Cambrai and Hainaut Province played a leading part in the so-called Franco-Flemish School.


title: Wallonia

text: Among them were Orlande de Lassus, Gilles Binchois, Guillaume Dufay In the 19th and 20th centuries, there was an emergence of major violinists, such as Henri Vieuxtemps, Eugène Ysaÿe (author of the unique opera in Walloon during the 20th century "Piére li houyeû" – Pierre the miner – based on a real incident which occurred in 1877 during a miners' strike in the Liège region), and Arthur Grumiaux, while Adolphe Sax (born in Dinant) invented the saxophone in 1846. The composer César Franck was born in Liège in 1822, Guillaume Lekeu in Verviers. More recently, André Souris (1899–1970) was associated with Surrealism. Zap Mama is a more international group.


title: Wallonia

text: Henri Pousseur is generally regarded as a member of the Darmstadt School in the 1950s. Pousseur's music employs serialism, mobile forms, and aleatory, often mediating between or among seemingly irreconcilable styles, such as those of Schubert and Webern ("Votre Faust"), or Pousseur's own serial style and the protest song "We shall overcome" ("Couleurs croisées"). He was strongly linked to the social strikes in Liège during the 1960s. He worked also with the French writer Michel Butor.


title: Wallonia

text: Walloon films are often characterized by social realism. It is perhaps the reason why the documentary "Misère au Borinage", and especially its co-director Henri Storck, is considered by Robert Stallaerts as the father of the Walloon cinema. He wrote: "Although a Fleming, he can be called the father of the Walloon cinema.". For F. André between "Misère au Borinage" and the films like those of the Dardenne brothers (since 1979), there is "Déjà s'envole la fleur maigre" (1960) (also shot in the Borinage), a film regarded as a point of reference in the history of the cinema. Like those of the Dardenne brothers, Thierry Michel, Jean-Jacques Andrien, Benoît Mariage, or, e.g. the social documentaries of Patric Jean, the director of Les enfants du Borinage writing his film as a letter to Henri Storck. On the other hand, films such as Thierry Zéno's "Vase de noces" (1974), "Mireille in the life of the others" by Jean-Marie Buchet (1979), "C'est arrivé près de chez vous" (English title: "Man bites dog") by Rémy Belvaux and André Bonzel (1992) and the works of Noël Godin and Jean-Jacques Rousseau are influenced by surrealism, absurdism and black comedy. The films of the Dardenne brothers are also inspired by the Bible and "Le Fils" for instance is regarded as one of the most spiritually significant films.


title: Wallonia

text: The Ducasse de Mons (Walloon French for Kermesse), is one of the UNESCO Masterpieces of the Oral and Intangible Heritage of Humanity. It comprises two important parts: the procession, the descent and the ascent of the shrine of Waltrude, and the combat between Saint George and the dragon. The combat (after the procession), plays out on the Trinity Sunday between 12:30 pm and 1:00 pm on the Mons's central square. It represents the fight between Saint George (the good) and the dragon (the evil). The dragon is a mannequin carried and moved by the "white men" ("fr:Hommes blancs"). The dragon fights Saint George by attacking with his tail. Saint George on his horse turns clockwise and the dragon turns in the other direction. Saint George finally kills the dragon.


title: Wallonia

text: The Gilles of Binche and the giants' procession in Ath are also UNESCO Masterpieces of the Oral and Intangible Heritage of Humanity.


title: Wallonia

text: Wallonia is famous for a number of different foods and drinks, a great many of which are specialties of certain cities or regions. The Liège waffle a rich, dense, sweet, and chewy waffle native to Liège, is the most popular type of waffle in Belgium, and can be found in stores and even vending machines throughout the country. Cougnou, or the "bread of Jesus", is a sweet bread typically eaten around Christmas time and found throughout the region.


title: Wallonia

text: Other specialties include Herve cheese, an apple butter called "sirop de Liège", the Garden strawberry of Wépion. Also notable is the Dinant specialty Flamiche: These cheese tarts are not found in window displays as they are meant to be eaten straight from the oven. As one restaurateur stated in a book about Walloon gastronomy "it is the client who waits for the flamiche, as the flamiche does not wait for the client". There are also the Ardennes ham, the "tarte al djote" from Nivelles, a dessert pie made with beet leaves and cheese, while tarte au riz is a rice-pudding filled pie from Verviers. The Walloons of the Door Peninsula in Wisconsin have a tradition of making what is called a Belgian Pie but which is a flat pie more like a pizza covered with prune purée and topped with a thin cheese layer. These were made by the dozens in outdoor stone ovens for the many kermisses, in a tradition that dates back to immigration in the 1850s.


title: Wallonia

text: A signature Walloon sausage is called Belgian Trippe among the Walloon community of Northeastern Wisconsin on the Door Peninsula. It is a blend of pork and cabbage made differently from household to household and probably based on a traditional Walloon sausage such as Boudin Verte d'Orp. Cussette is a fresh cheese which gets its airborne "P. roqueforti" culture from a tradition of making it in the kitchen. This is aged only one week at 30 degrees C, until it develops a faint blue cast and a tang. Walloon headcheese differs from the German in that it is more finely ground, includes bits of cartilage, and is allowed to sit for a month or two in a cool place before being eaten.


title: Wallonia

text: In terms of drink, Wallonia mirrors Belgium as a whole; beer and wine are both popular, and a great diversity of beers are made and enjoyed in Wallonia. Installed in Bierghes in the Senne valley, the Gueuzerie Tilquin is the only gueuze blendery in Wallonia. Wallonia boasts three of the seven Trappist beers (from Chimay, Orval and Rochefort) in addition to a great number of other locally brewed beers. Wallonia is also home to the last bastion of traditional rustic "saison", most notably those produced at the Brasserie de Silly and the Brasserie Dupont (located in , in the region of Western Hainaut Province historically known for its production of rustic farmhouse ales). Jupiler, the best-selling beer in Belgium, is brewed in Jupille-sur-Meuse in Liège. Wallonia also home to a Jenever called Peket, and a May wine called Maitrank.


title: Wallonia

text: The two largest cities in Wallonia each have an airport. The Brussels South Charleroi Airport has become an important passenger airport, especially with low fares companies such as Ryanair or Wizzair. It serves as a low-cost alternative to Brussels Airport, and it saw 7 303 720 passengers in 2016. The Liège Airport is specialized in freight, although it also operates tourist-oriented charter flights. Today, Liège is the 8th airport for European freight and aims to reach the 5th rank in the next decade.


title: Wallonia

text: TEC is the single public transit authority for all of Wallonia, operating buses and trams. Charleroi is the sole Walloon city to have a metro system, the Charleroi Pre-metro.


title: Wallonia

text: Wallonia has an extensive and well-developed rail network, served by the Belgian National Railway Company, SNCB.


title: Wallonia

text: Wallonia's numerous motorways fall within the scope of the TransEuropean Transport network programme (TEN-T). This priority programme run by the European Union provides more than 70,000 km of transport infrastructure, including motorways, express rail lines and roadways, and has been developed to carry substantial volumes of traffic.


title: Wallonia

text: With traffic of over 20 million tonnes and 26 kilometres of quays, the autonomous port of Liège (PAL) is the third largest inland port in Europe. It carries out the management of 31 ports along the Meuse and the Albert Canal. It is accessible to sea and river transporters weighing up to 2,500 tonnes, and to push two-barge convoys (4,500 tonnes, soon to be raised to 9,000 tonnes). Even if Wallonia does not have direct access to the sea, it is very well connected to the major ports thanks to an extensive network of navigable waterways that pervades Belgium, and it has effective river connections to Antwerp, Rotterdam and Dunkirk.


title: Wallonia

text: On the west side of Wallonia, in Hainaut Province, the Strépy-Thieu boat lift, permits river traffic of up to the new 1350-tonne standard to pass between the waterways of the Meuse and Scheldt rivers. Completed in 2002 at an estimated cost of €160 million (then 6.4 billion Belgian francs) the lift has increased river traffic from 256 kT in 2001 to 2,295 kT in 2006.


title: Wallonia

text: The Walloon Export and Foreign Investment Agency (AWEX) is the Wallonia Region of Belgium's government agency in charge of foreign trade promotion and foreign investment attraction.


title: Wallonia

text: The AWEX organizes regular trade missions to the promising market of Kazakhstan, where it has a representative office in Almaty. In 2017, the AWEX together with the Flanders Investment and Trade brought a delegation of 30 companies to Astana and Almaty, the two largest cities in Kazakhstan.


title: The Beauty Inside (TV series)

text: The Beauty Inside () is a 2018 South Korean television series based on the 2015 film of the same name; starring Seo Hyun-jin, Lee Min-ki, Lee Da-hee, and Ahn Jae-hyun. It aired on JTBC from October 1 to November 20, 2018.


title: The Beauty Inside (TV series)

text: About the love story of Han Se-gye (Seo Hyun-jin) who is an A-list actress. She is known as a troublemaker and the object of many rumors. Her life is a mystery, but, in reality, she suffers from an unusual phenomenon. At a certain point every month, her appearance changes to a different person. Seo Do-jae (Lee Min-ki) who is an executive director of an airline company, seems perfect. He is attractive and intelligent but he actually suffers from prosopagnosia. The two eventually fall in love.


title: Caesium

text: Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at . It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. The element has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors.


title: Caesium

text: The German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium were as a "getter" in vacuum tubes and in photoelectric cells. In 1967, acting on Einstein's proof that the speed of light is the most-constant dimension in the universe, the International System of Units used two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the metre. Since then, caesium has been widely used in highly accurate atomic clocks.


title: Caesium

text: Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids, but it has a range of applications in the production of electricity, in electronics, and in chemistry. The radioactive isotope caesium-137 has a half-life of about 30 years and is used in medical applications, industrial gauges, and hydrology. Nonradioactive caesium compounds are only mildly toxic, but the pure metal's tendency to react explosively with water means that caesium is considered a hazardous material, and the radioisotopes present a significant health and ecological hazard in the environment.


title: Caesium

text: Of all elements that are solid at room temperature, caesium is the softest: it has a hardness of 0.2 Mohs. It is a very ductile, pale metal, which darkens in the presence of trace amounts of oxygen. When in the presence of mineral oil (where it is best kept during transport), it loses its metallic lustre and takes on a duller, grey appearance. It has a melting point of , making it one of the few elemental metals that are liquid near room temperature. Mercury is the only stable elemental metal with a known melting point lower than caesium. In addition, the metal has a rather low boiling point, , the lowest of all metals other than mercury. Its compounds burn with a blue or violet colour.


title: Caesium

text: Caesium forms alloys with the other alkali metals, gold, and mercury (amalgams). At temperatures below , it does not alloy with cobalt, iron, molybdenum, nickel, platinum, tantalum, or tungsten. It forms well-defined intermetallic compounds with antimony, gallium, indium, and thorium, which are photosensitive. It mixes with all the other alkali metals (except lithium); the alloy with a molar distribution of 41% caesium, 47% potassium, and 12% sodium has the lowest melting point of any known metal alloy, at . A few amalgams have been studied: is black with a purple metallic lustre, while CsHg is golden-coloured, also with a metallic lustre.


title: Caesium

text: The golden colour of caesium comes from the decreasing frequency of light required to excite electrons of the alkali metals as the group is descended. For lithium through rubidium this frequency is in the ultraviolet, but for caesium it enters the blue–violet end of the spectrum; in other words, the plasmonic frequency of the alkali metals becomes lower from lithium to caesium. Thus caesium transmits and partially absorbs violet light preferentially while other colours (having lower frequency) are reflected; hence it appears yellowish.


title: Caesium

text: Caesium metal is highly reactive and very pyrophoric. It ignites spontaneously in air, and reacts explosively with water even at low temperatures, more so than the other alkali metals (first group of the periodic table). It reacts with ice at temperatures as low as . Because of this high reactivity, caesium metal is classified as a hazardous material. It is stored and shipped in dry, saturated hydrocarbons such as mineral oil. It can be handled only under inert gas, such as argon. However, a caesium-water explosion is often less powerful than a sodium-water explosion with a similar amount of sodium. This is because caesium explodes instantly upon contact with water, leaving little time for hydrogen to accumulate. Caesium can be stored in vacuum-sealed borosilicate glass ampoules. In quantities of more than about , caesium is shipped in hermetically sealed, stainless steel containers.


title: Caesium

text: The chemistry of caesium is similar to that of other alkali metals, in particular rubidium, the element above caesium in the periodic table. As expected for an alkali metal, the only common oxidation state is +1. Some slight differences arise from the fact that it has a higher atomic mass and is more electropositive than other (nonradioactive) alkali metals. Caesium is the most electropositive chemical element. The caesium ion is also larger and less "hard" than those of the lighter alkali metals.


title: Caesium

text: Most caesium compounds contain the element as the cation , which binds ionically to a wide variety of anions. One noteworthy exception is the caeside anion (), and others are the several suboxides (see section on oxides below). More recently, caesium is predicted to behave as a p-block element and capable of forming higher fluorides with higher oxidation states (i.e., CsF with n > 1) under high pressure. This prediction needs to be validated by further experiments.


title: Caesium

text: Salts of Cs are usually colourless unless the anion itself is coloured. Many of the simple salts are hygroscopic, but less so than the corresponding salts of lighter alkali metals. The phosphate, acetate, carbonate, halides, oxide, nitrate, and sulfate salts are water-soluble. Its double salts are often less soluble, and the low solubility of caesium aluminium sulfate is exploited in refining Cs from ores. The double salts with antimony (such as ), bismuth, cadmium, copper, iron, and lead are also poorly soluble.


title: Caesium

text: Caesium hydroxide (CsOH) is hygroscopic and strongly basic. It rapidly etches the surface of semiconductors such as silicon. CsOH has been previously regarded by chemists as the "strongest base", reflecting the relatively weak attraction between the large Cs ion and OH; it is indeed the strongest Arrhenius base; however, a number of compounds such as "n"-butyllithium, sodium amide, sodium hydride, caesium hydride, etc., which cannot be dissolved in water as reacting violently with it but rather only used in some anhydrous polar aprotic solvents, are far more basic on the basis of the Brønsted–Lowry acid–base theory.


title: Caesium

text: A stoichiometric mixture of caesium and gold will react to form yellow caesium auride (CsAu) upon heating. The auride anion here behaves as a pseudohalogen. The compound reacts violently with water, yielding caesium hydroxide, metallic gold, and hydrogen gas; in liquid ammonia it can be reacted with a caesium-specific ion exchange resin to produce tetramethylammonium auride. The analogous platinum compound, red caesium platinide (CsPt), contains the platinide ion that behaves as a pseudochalcogen.


title: Caesium

text: Like all metal cations, Cs forms complexes with Lewis bases in solution. Because of its large size, Cs usually adopts coordination numbers greater than 6, the number typical for the smaller alkali metal cations. This difference is apparent in the 8-coordination of CsCl. This high coordination number and softness (tendency to form covalent bonds) are properties exploited in separating Cs from other cations in the remediation of nuclear wastes, where Cs must be separated from large amounts of nonradioactive K.


title: Caesium

text: Caesium fluoride (CsF) is a hygroscopic white solid that is widely used in organofluorine chemistry as a source of fluoride anions. Caesium fluoride has the halite structure, which means that the Cs and F pack in a cubic closest packed array as do Na and Cl in sodium chloride. Notably, caesium and fluorine have the lowest and highest electronegativities, respectively, among all the known elements.


title: Caesium

text: Caesium chloride (CsCl) crystallizes in the simple cubic crystal system. Also called the "caesium chloride structure", this structural motif is composed of a primitive cubic lattice with a two-atom basis, each with an eightfold coordination; the chloride atoms lie upon the lattice points at the edges of the cube, while the caesium atoms lie in the holes in the centre of the cubes. This structure is shared with CsBr and CsI, and many other compounds that do not contain Cs. In contrast, most other alkaline halides have the sodium chloride (NaCl) structure. The CsCl structure is preferred because Cs has an ionic radius of 174 pm and 181 pm.


title: Caesium

text: More so than the other alkali metals, caesium forms numerous binary compounds with oxygen. When caesium burns in air, the superoxide is the main product. The "normal" caesium oxide () forms yellow-orange hexagonal crystals, and is the only oxide of the anti- type. It vaporizes at , and decomposes to caesium metal and the peroxide at temperatures above . In addition to the superoxide and the ozonide , several brightly coloured suboxides have also been studied. These include , , , (dark-green), CsO, , as well as . The latter may be heated in a vacuum to generate . Binary compounds with sulfur, selenium, and tellurium also exist.


title: Caesium

text: Caesium has 40 known isotopes, ranging in mass number (i.e. number of nucleons in the nucleus) from 112 to 151. Several of these are synthesized from lighter elements by the slow neutron capture process (S-process) inside old stars and by the R-process in supernova explosions. The only stable caesium isotope is Cs, with 78 neutrons. Although it has a large nuclear spin (+), nuclear magnetic resonance studies can use this isotope at a resonating frequency of 11.7 MHz.


title: Caesium

text: The radioactive Cs has a very long half-life of about 2.3 million years, the longest of all radioactive isotopes of caesium. Cs and Cs have half-lives of 30 and two years, respectively. Cs decomposes to a short-lived Ba by beta decay, and then to nonradioactive barium, while Cs transforms into Ba directly. The isotopes with mass numbers of 129, 131, 132 and 136, have half-lives between a day and two weeks, while most of the other isotopes have half-lives from a few seconds to fractions of a second. At least 21 metastable nuclear isomers exist. Other than Cs (with a half-life of just under 3 hours), all are very unstable and decay with half-lives of a few minutes or less.


title: Caesium

text: The isotope Cs is one of the long-lived fission products of uranium produced in nuclear reactors. However, this fission product yield is reduced in most reactors because the predecessor, Xe, is a potent neutron poison and frequently transmutes to stable Xe before it can decay to Cs.


title: Caesium

text: The beta decay from Cs to Ba is a strong emission of gamma radiation. Cs and Sr are the principal medium-lived products of nuclear fission, and the prime sources of radioactivity from spent nuclear fuel after several years of cooling, lasting several hundred years. Those two isotopes are the largest source of residual radioactivity in the area of the Chernobyl disaster. Because of the low capture rate, disposing of Cs through neutron capture is not feasible and the only current solution is to allow it to decay over time.


title: Caesium

text: Almost all caesium produced from nuclear fission comes from the beta decay of originally more neutron-rich fission products, passing through various isotopes of iodine and xenon. Because iodine and xenon are volatile and can diffuse through nuclear fuel or air, radioactive caesium is often created far from the original site of fission. With nuclear weapons testing in the 1950s through the 1980s, Cs was released into the atmosphere and returned to the surface of the earth as a component of radioactive fallout. It is a ready marker of the movement of soil and sediment from those times.


title: Caesium

text: Caesium is a relatively rare element, estimated to average 3 parts per million in the Earth's crust. It is the 45th most abundant element and the 36th among the metals. Nevertheless, it is more abundant than such elements as antimony, cadmium, tin, and tungsten, and two orders of magnitude more abundant than mercury and silver; it is 3.3% as abundant as rubidium, with which it is closely associated, chemically.


title: Caesium

text: Due to its large ionic radius, caesium is one of the "incompatible elements". During magma crystallization, caesium is concentrated in the liquid phase and crystallizes last. Therefore, the largest deposits of caesium are zone pegmatite ore bodies formed by this enrichment process. Because caesium does not substitute for potassium as readily as rubidium does, the alkali evaporite minerals sylvite (KCl) and carnallite () may contain only 0.002% caesium. Consequently, caesium is found in few minerals. Percentage amounts of caesium may be found in beryl () and avogadrite (), up to 15 wt% CsO in the closely related mineral pezzottaite (), up to 8.4 wt% CsO in the rare mineral londonite (), and less in the more widespread rhodizite. The only economically important ore for caesium is pollucite , which is found in a few places around the world in zoned pegmatites, associated with the more commercially important lithium minerals, lepidolite and petalite. Within the pegmatites, the large grain size and the strong separation of the minerals results in high-grade ore for mining.


title: Caesium

text: The world's most significant and richest known source of caesium is the Tanco Mine at Bernic Lake in Manitoba, Canada, estimated to contain 350,000 metric tons of pollucite ore, representing more than two-thirds of the world's reserve base. Although the stoichiometric content of caesium in pollucite is 42.6%, pure pollucite samples from this deposit contain only about 34% caesium, while the average content is 24 wt%. Commercial pollucite contains more than 19% caesium. The Bikita pegmatite deposit in Zimbabwe is mined for its petalite, but it also contains a significant amount of pollucite. Another notable source of pollucite is in the Karibib Desert, Namibia. At the present rate of world mine production of 5 to 10 metric tons per year, reserves will last for thousands of years.


title: Caesium

text: Mining and refining pollucite ore is a selective process and is conducted on a smaller scale than for most other metals. The ore is crushed, hand-sorted, but not usually concentrated, and then ground. Caesium is then extracted from pollucite primarily by three methods: acid digestion, alkaline decomposition, and direct reduction.


title: Caesium

text: In the acid digestion, the silicate pollucite rock is dissolved with strong acids, such as hydrochloric (HCl), sulfuric (), hydrobromic (HBr), or hydrofluoric (HF) acids. With hydrochloric acid, a mixture of soluble chlorides is produced, and the insoluble chloride double salts of caesium are precipitated as caesium antimony chloride (), caesium iodine chloride (), or caesium hexachlorocerate (). After separation, the pure precipitated double salt is decomposed, and pure CsCl is precipitated by evaporating the water.


title: Caesium

text: The sulfuric acid method yields the insoluble double salt directly as caesium alum (). The aluminium sulfate component is converted to insoluble aluminium oxide by roasting the alum with carbon, and the resulting product is leached with water to yield a solution.


title: Caesium

text: Roasting pollucite with calcium carbonate and calcium chloride yields insoluble calcium silicates and soluble caesium chloride. Leaching with water or dilute ammonia () yields a dilute chloride (CsCl) solution. This solution can be evaporated to produce caesium chloride or transformed into caesium alum or caesium carbonate. Though not commercially feasible, the ore can be directly reduced with potassium, sodium, or calcium in vacuum to produce caesium metal directly.


title: Caesium

text: Most of the mined caesium (as salts) is directly converted into caesium formate (HCOOCs) for applications such as oil drilling. To supply the developing market, Cabot Corporation built a production plant in 1997 at the Tanco mine near Bernic Lake in Manitoba, with a capacity of per year of caesium formate solution. The primary smaller-scale commercial compounds of caesium are caesium chloride and nitrate.


title: Caesium

text: Alternatively, caesium metal may be obtained from the purified compounds derived from the ore. Caesium chloride and the other caesium halides can be reduced at with calcium or barium, and caesium metal distilled from the result. In the same way, the aluminate, carbonate, or hydroxide may be reduced by magnesium.


title: Caesium

text: The metal can also be isolated by electrolysis of fused caesium cyanide (CsCN). Exceptionally pure and gas-free caesium can be produced by thermal decomposition of caesium azide , which can be produced from aqueous caesium sulfate and barium azide. In vacuum applications, caesium dichromate can be reacted with zirconium to produce pure caesium metal without other gaseous products.


title: Caesium

text: The price of 99.8% pure caesium (metal basis) in 2009 was about , but the compounds are significantly cheaper.


title: Caesium

text: In 1860, Robert Bunsen and Gustav Kirchhoff discovered caesium in the mineral water from Dürkheim, Germany. Because of the bright blue lines in the emission spectrum, they derived the name from the Latin word "caesius", meaning sky-blue. Caesium was the first element to be discovered with a spectroscope, which had been invented by Bunsen and Kirchhoff only a year previously.


title: Caesium

text: To obtain a pure sample of caesium, of mineral water had to be evaporated to yield of concentrated salt solution. The alkaline earth metals were precipitated either as sulfates or oxalates, leaving the alkali metal in the solution. After conversion to the nitrates and extraction with ethanol, a sodium-free mixture was obtained. From this mixture, the lithium was precipitated by ammonium carbonate. Potassium, rubidium, and caesium form insoluble salts with chloroplatinic acid, but these salts show a slight difference in solubility in hot water, and the less-soluble caesium and rubidium hexachloroplatinate ((Cs,Rb)PtCl) were obtained by fractional crystallization. After reduction of the hexachloroplatinate with hydrogen, caesium and rubidium were separated by the difference in solubility of their carbonates in alcohol. The process yielded of rubidium chloride and of caesium chloride from the initial 44,000 litres of mineral water.


title: Caesium

text: From the caesium chloride, the two scientists estimated the atomic weight of the new element at 123.35 (compared to the currently accepted one of 132.9). They tried to generate elemental caesium by electrolysis of molten caesium chloride, but instead of a metal, they obtained a blue homogeneous substance which "neither under the naked eye nor under the microscope showed the slightest trace of metallic substance"; as a result, they assigned it as a subchloride (). In reality, the product was probably a colloidal mixture of the metal and caesium chloride. The electrolysis of the aqueous solution of chloride with a mercury cathode produced a caesium amalgam which readily decomposed under the aqueous conditions. The pure metal was eventually isolated by the Swedish chemist Carl Setterberg while working on his doctorate with Kekulé and Bunsen. In 1882, he produced caesium metal by electrolysing caesium cyanide, avoiding the problems with the chloride.


title: Caesium

text: Historically, the most important use for caesium has been in research and development, primarily in chemical and electrical fields. Very few applications existed for caesium until the 1920s, when it came into use in radio vacuum tubes, where it had two functions; as a getter, it removed excess oxygen after manufacture, and as a coating on the heated cathode, it increased the electrical conductivity. Caesium was not recognized as a high-performance industrial metal until the 1950s. Applications for nonradioactive caesium included photoelectric cells, photomultiplier tubes, optical components of infrared spectrophotometers, catalysts for several organic reactions, crystals for scintillation counters, and in magnetohydrodynamic power generators. Caesium is also used as a source of positive ions in secondary ion mass spectrometry (SIMS).


title: Caesium

text: Since 1967, the International System of Measurements has based the primary unit of time, the second, on the properties of caesium. The International System of Units (SI) defines the second as the duration of 9,192,631,770 cycles at the microwave frequency of the spectral line corresponding to the transition between two hyperfine energy levels of the ground state of caesium-133. The 13th General Conference on Weights and Measures of 1967 defined a second as: "the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of caesium-133 atoms in their ground state undisturbed by external fields".


title: Caesium

text: The largest present-day use of nonradioactive caesium is in caesium formate drilling fluids for the extractive oil industry. Aqueous solutions of caesium formate (HCOOCs)—made by reacting caesium hydroxide with formic acid—were developed in the mid-1990s for use as oil well drilling and completion fluids. The function of a drilling fluid is to lubricate drill bits, to bring rock cuttings to the surface, and to maintain pressure on the formation during drilling of the well. Completion fluids assist the emplacement of control hardware after drilling but prior to production by maintaining the pressure.


title: Caesium

text: The high density of the caesium formate brine (up to 2.3 g/cm, or 19.2 pounds per gallon), coupled with the relatively benign nature of most caesium compounds, reduces the requirement for toxic high-density suspended solids in the drilling fluid—a significant technological, engineering and environmental advantage. Unlike the components of many other heavy liquids, caesium formate is relatively environment-friendly. Caesium formate brine can be blended with potassium and sodium formates to decrease the density of the fluids to that of water (1.0 g/cm, or 8.3 pounds per gallon). Furthermore, it is biodegradable and may be recycled, which is important in view of its high cost (about $4,000 per barrel in 2001). Alkali formates are safe to handle and do not damage the producing formation or downhole metals as corrosive alternative, high-density brines (such as zinc bromide solutions) sometimes do; they also require less cleanup and reduce disposal costs.


title: Caesium

text: Caesium-based atomic clocks use the electromagnetic transitions in the hyperfine structure of caesium-133 atoms as a reference point. The first accurate caesium clock was built by Louis Essen in 1955 at the National Physical Laboratory in the UK. Caesium clocks have improved over the past half-century and are regarded as "the most accurate realization of a unit that mankind has yet achieved." These clocks measure frequency with an error of 2 to 3 parts in 10, which corresponds to an accuracy of 2 nanoseconds per day, or one second in 1.4 million years. The latest versions are more accurate than 1 part in 10, about 1 second in 20 million years. The caesium standard is the primary standard for standards-compliant time and frequency measurements. Caesium clocks regulate the timing of cell phone networks and the Internet.


title: Caesium

text: The second, symbol "s", is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency , the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be when expressed in the unit Hz, which is equal to s.


title: Caesium

text: Caesium vapour thermionic generators are low-power devices that convert heat energy to electrical energy. In the two-electrode vacuum tube converter, caesium neutralizes the space charge near the cathode and enhances the current flow.


title: Caesium

text: Caesium is also important for its photoemissive properties, converting light to electron flow. It is used in photoelectric cells because caesium-based cathodes, such as the intermetallic compound , have a low threshold voltage for emission of electrons. The range of photoemissive devices using caesium include optical character recognition devices, photomultiplier tubes, and video camera tubes. Nevertheless, germanium, rubidium, selenium, silicon, tellurium, and several other elements can be substituted for caesium in photosensitive materials.


title: Caesium

text: Caesium iodide (CsI), bromide (CsBr) and caesium fluoride (CsF) crystals are employed for scintillators in scintillation counters widely used in mineral exploration and particle physics research to detect gamma and X-ray radiation. Being a heavy element, caesium provides good stopping power with better detection. Caesium compounds may provide a faster response (CsF) and be less hygroscopic (CsI).


title: Caesium

text: The element is used as an internal standard in spectrophotometry. Like other alkali metals, caesium has a great affinity for oxygen and is used as a "getter" in vacuum tubes. Other uses of the metal include high-energy lasers, vapour glow lamps, and vapour rectifiers.


title: Caesium

text: The high density of the caesium ion makes solutions of caesium chloride, caesium sulfate, and caesium trifluoroacetate () useful in molecular biology for density gradient ultracentrifugation. This technology is used primarily in the isolation of viral particles, subcellular organelles and fractions, and nucleic acids from biological samples.


title: Caesium

text: Relatively few chemical applications use caesium. Doping with caesium compounds enhances the effectiveness of several metal-ion catalysts for chemical synthesis, such as acrylic acid, anthraquinone, ethylene oxide, methanol, phthalic anhydride, styrene, methyl methacrylate monomers, and various olefins. It is also used in the catalytic conversion of sulfur dioxide into sulfur trioxide in the production of sulfuric acid.


title: Caesium

text: Caesium fluoride enjoys a niche use in organic chemistry as a base and as an anhydrous source of fluoride ion. Caesium salts sometimes replace potassium or sodium salts in organic synthesis, such as cyclization, esterification, and polymerization. Caesium has also been used in thermoluminescent radiation dosimetry : When exposed to radiation, it acquires crystal defects that, when heated, revert with emission of light proportionate to the received dose. Thus, measuring the light pulse with a photomultiplier tube can allow the accumulated radiation dose to be quantified.


title: Caesium

text: Caesium-137 is a radioisotope commonly used as a gamma-emitter in industrial applications. Its advantages include a half-life of roughly 30 years, its availability from the nuclear fuel cycle, and having Ba as a stable end product. The high water solubility is a disadvantage which makes it incompatible with large pool irradiators for food and medical supplies. It has been used in agriculture, cancer treatment, and the sterilization of food, sewage sludge, and surgical equipment. Radioactive isotopes of caesium in radiation devices were used in the medical field to treat certain types of cancer, but emergence of better alternatives and the use of water-soluble caesium chloride in the sources, which could create wide-ranging contamination, gradually put some of these caesium sources out of use. Caesium-137 has been employed in a variety of industrial measurement gauges, including moisture, density, levelling, and thickness gauges. It has also been used in well logging devices for measuring the electron density of the rock formations, which is analogous to the bulk density of the formations.


title: Caesium

text: Caesium-137 has been used in hydrologic studies analogous to those with tritium. As a daughter product of fission bomb testing from the 1950s through the mid-1980s, caesium-137 was released into the atmosphere, where it was absorbed readily into solution. Known year-to-year variation within that period allows correlation with soil and sediment layers. Caesium-134, and to a lesser extent caesium-135, have also been used in hydrology to measure the caesium output by the nuclear power industry. While they are less prevalent than either caesium-133 or caesium-137, these bellwether isotopes are produced solely from anthropogenic sources.


title: Caesium

text: Caesium and mercury were used as a propellant in early ion engines designed for spacecraft propulsion on very long interplanetary or extraplanetary missions. The fuel was ionized by contact with a charged tungsten electrode. But corrosion by caesium on spacecraft components has pushed development in the direction of inert gas propellants, such as xenon, which are easier to handle in ground-based tests and do less potential damage to the spacecraft. Xenon was used in the experimental spacecraft Deep Space 1 launched in 1998. Nevertheless, field-emission electric propulsion thrusters that accelerate liquid metal ions such as caesium have been built.


title: Caesium

text: Caesium nitrate is used as an oxidizer and pyrotechnic colorant to burn silicon in infrared flares, such as the LUU-19 flare, because it emits much of its light in the near infrared spectrum. Caesium compounds may have been used as fuel additives to reduce the radar signature of exhaust plumes in the Lockheed A-12 CIA reconnaissance aircraft. Caesium and rubidium have been added as a carbonate to glass because they reduce electrical conductivity and improve stability and durability of fibre optics and night vision devices. Caesium fluoride or caesium aluminium fluoride are used in fluxes formulated for brazing aluminium alloys that contain magnesium.


title: Caesium

text: Magnetohydrodynamic (MHD) power-generating systems were researched, but failed to gain widespread acceptance. Caesium metal has also been considered as the working fluid in high-temperature Rankine cycle turboelectric generators.


title: Caesium

text: Caesium salts have been evaluated as antishock reagents following the administration of arsenical drugs. Because of their effect on heart rhythms, however, they are less likely to be used than potassium or rubidium salts. They have also been used to treat epilepsy.


title: Caesium

text: Caesium-133 can be laser cooled and used to probe fundamental and technological problems in quantum physics. It has a particularly convenient Feshbach spectrum to enable studies of ultracold atoms requiring tunable interactions.


title: Caesium

text: Nonradioactive caesium compounds are only mildly toxic, and nonradioactive caesium is not a significant environmental hazard. Because biochemical processes can confuse and substitute caesium with potassium, excess caesium can lead to hypokalemia, arrhythmia, and acute cardiac arrest, but such amounts would not ordinarily be encountered in natural sources.


title: Caesium

text: The median lethal dose (LD) for caesium chloride in mice is 2.3 g per kilogram, which is comparable to the LD values of potassium chloride and sodium chloride. The principal use of nonradioactive caesium is as caesium formate in petroleum drilling fluids because it is much less toxic than alternatives, though it is more costly.


title: Caesium

text: Caesium metal is one of the most reactive elements and is highly explosive in the presence of water. The hydrogen gas produced by the reaction is heated by the thermal energy released at the same time, causing ignition and a violent explosion. This can occur with other alkali metals, but caesium is so potent that this explosive reaction can be triggered even by cold water.


title: Caesium

text: It is highly pyrophoric: the autoignition temperature of caesium is , and it ignites explosively in air to form caesium hydroxide and various oxides. Caesium hydroxide is a very strong base, and will rapidly corrode glass.


title: Caesium

text: The isotopes 134 and 137 are present in the biosphere in small amounts from human activities, differing by location. Radiocaesium does not accumulate in the body as readily as other fission products (such as radioiodine and radiostrontium). About 10% of absorbed radiocaesium washes out of the body relatively quickly in sweat and urine. The remaining 90% has a biological half-life between 50 and 150 days. Radiocaesium follows potassium and tends to accumulate in plant tissues, including fruits and vegetables. Plants vary widely in the absorption of caesium, sometimes displaying great resistance to it. It is also well-documented that mushrooms from contaminated forests accumulate radiocaesium (caesium-137) in the fungal sporocarps. Accumulation of caesium-137 in lakes has been a great concern after the Chernobyl disaster. Experiments with dogs showed that a single dose of 3.8 millicuries (140 MBq, 4.1 μg of caesium-137) per kilogram is lethal within three weeks; smaller amounts may cause infertility and cancer. The International Atomic Energy Agency and other sources have warned that radioactive materials, such as caesium-137, could be used in radiological dispersion devices, or "dirty bombs".


title: Systems theory

text: Systems theory is the interdisciplinary study of systems, i.e. cohesive groups of interrelated, interdependent components that can be natural or human-made. Every system has causal boundaries, is influenced by its context, defined by its structure, function and role, and expressed through its relations with other systems. A system is "more than the sum of its parts" by expressing synergy or emergent behavior.


title: Systems theory

text: Changing one component of a system may affect other components or the whole system. It may be possible to predict these changes in patterns of behavior. For systems that learn and adapt, the growth and the degree of adaptation depend upon how well the system is engaged with its environment and other contexts influencing its organization. Some systems support other systems, maintaining the other system to prevent failure. The goals of systems theory are to model a system's dynamics, constraints, conditions, and relations; and to elucidate principles (such as purpose, measure, methods, tools) that can be discerned and applied to other systems at every level of nesting, and in a wide range of fields for achieving optimized equifinality.


title: Systems theory

text: General systems theory is about developing broadly applicable concepts and principles, as opposed to concepts and principles specific to one domain of knowledge. It distinguishes dynamic or active systems from static or passive systems. Active systems are activity structures or components that interact in behaviours and processes or interrelate through formal contextual boundary conditions (attractors). Passive systems are structures and components that are being processed. For example, a program is passive when it is a disc file and active when it runs in memory. The field is related to systems thinking, machine logic, and systems engineering.


title: Systems theory

text: Systems theory is manifest in the work of practitioners in many disciplines, for example the works of biologist Ludwig von Bertalanffy, linguist Béla H. Bánáthy, and sociologist Talcott Parsons; in the study of ecological systems by Howard T. Odum, Eugene Odum; in Fritjof Capra's study of organizational theory; in the study of management by Peter Senge; in interdisciplinary areas such as Human Resource Development in the works of Richard A. Swanson; and in the works of educators Debora Hammond and Alfonso Montuori.


title: Systems theory

text: As a transdisciplinary, interdisciplinary, and multiperspectival endeavor, systems theory brings together principles and concepts from ontology, the philosophy of science, physics, computer science, biology, and engineering, as well as geography, sociology, political science, psychotherapy (especially family systems therapy), and economics.


title: Systems theory

text: Systems theory promotes dialogue between autonomous areas of study as well as within systems science itself. In this respect, with the possibility of misinterpretations, von Bertalanffy believed a general theory of systems "should be an important regulative device in science," to guard against superficial analogies that "are useless in science and harmful in their practical consequences."


title: Systems theory

text: Others remain closer to the direct systems concepts developed by the original systems theorists. For example, Ilya Prigogine, of the Center for Complex Quantum Systems at the University of Texas, has studied emergent properties, suggesting that they offer analogues for living systems. The distinction of autopoiesis as made by Humberto Maturana and Francisco Varela represent further developments in this field. Important names in contemporary systems science include Russell Ackoff, Ruzena Bajcsy, Béla H. Bánáthy, Gregory Bateson, Anthony Stafford Beer, Peter Checkland, Barbara Grosz, Brian Wilson, Robert L. Flood, Allenna Leonard, Radhika Nagpal, Fritjof Capra, Warren McCulloch, Kathleen Carley, Michael C. Jackson, Katia Sycara, and Edgar Morin among others.


title: Systems theory

text: With the modern foundations for a general theory of systems following World War I, Ervin László, in the preface for Bertalanffy's book, "Perspectives on General System Theory", points out that the translation of "general system theory" from German into English has "wrought a certain amount of havoc":


title: Systems theory

text: Theorie (or "Lehre") "has a much broader meaning in German than the closest English words 'theory' and 'science'," just as "Wissenschaft" (or 'Science'). These ideas refer to an organized body of knowledge and "any systematically presented set of concepts, whether empirically, axiomatically, or philosophically" represented, while many associate "Lehre" with theory and science in the etymology of general systems, though it also does not translate from the German very well; its "closest equivalent" translates to 'teaching', but "sounds dogmatic and off the mark." An adequate overlap in meaning is found within the word "nomothetic", which can mean "having the capability to posit long-lasting sense." While the idea of a "general systems theory" might have lost many of its root meanings in the translation, by defining a new way of thinking about science and scientific paradigms, systems theory became a widespread term used for instance to describe the interdependence of relationships created in organizations.


title: Systems theory

text: A system in this frame of reference can contain regularly interacting or interrelating groups of activities. For example, in noting the influence in the evolution of "an individually oriented industrial psychology [into] a systems and developmentally oriented organizational psychology," some theorists recognize that organizations have complex social systems; separating the parts from the whole reduces the overall effectiveness of organizations. This difference, from conventional models that center on individuals, structures, departments and units, separates in part from the whole, instead of recognizing the interdependence between groups of individuals, structures and processes that enable an organization to function.