Expressions of modality.

Classically, three categories of modality are distinguished in linguistics: epistemic, deontic and circumstantial (or 'root') modality. Epistemic modality is possibility and necessity relative to a speaker's knowledge, while deontic modality has to do with permissions and obligations according to some system of rules. Circumstantial modality is relative to the relevant circumstances of a conversation and in general dependent on facts of the world rather than the agent's knowledge. These different modalities can be expressed by auxiliaries such as'must' or 'can', and can be illustrated in the English example below:  The sentence in (1) might be spoken by someone who has decided that all of the relevant facts in a particular murder investigation point to the conclusion that Agatha was the murderer, even though it may or may not actually be the case. The'must' in this sentence thus expresses epistemic modality, for 'for all we know', Agatha must be the murderer - where 'for all we know' is relative to some knowledge the speakers possess. In contrast, (2) might be spoken by someone who has decided that, according to some standard of conduct, Agatha has committed a vile crime, and therefore the correct course of action is to jail Agatha. The'must' in sentence (3) has neither an epistemic reading (that Agatha must sneeze is not dependent on some speaker's knowledge), nor a deontic reading (it is not the case that Agatha must sneeze according to the law). Rather, that Agatha must sneeze is relative to the relevant circumstances of the utterance. Although the English'must' is ambiguous between these interpretations, the form of the other elements in the sentences helps to disambiguate.  In standard formal approaches to linguistic modality, an utterance expressing modality is one that can always roughly be paraphrased to fit the following template:  The set of propositions which forms the basis of evaluation is called the modal base. The result of the evaluation is called the modal force. For example, the utterance in (2) expresses that, according to what the speaker has observed, it is necessary to conclude that John has a rather high income:  The modal base here is the knowledge of the speaker, the modal force is necessity. By contrast, (3) could be paraphrased as ‘Given his abilities, the strength of his teeth, etc., it is possible for John to open a beer bottle with his teeth’. Here, the modal base is defined by a subset of John's abilities, the modal force is possibility.

Semantic accounts.

Semantic approaches dealing with modality are traditionally based on the principles of modal logic. Both work with the notion that propositions can be mapped to sets of possible worlds; that is, a proposition can be defined as the set of worlds in which that proposition is true. For example, the proposition ‘the earth is flat’ corresponds to the set of possible worlds in which the earth is in fact flat.  In this framework, modal expressions such as "must" and "can" are then analyzed as quantifiers over a set of possible worlds. This set of worlds is given by the modal base and is said to be "the set of accessible worlds": For example, in sentence (2) above, the modal base is the knowledge the speaker has in the actual world. Therefore, the set of accessible worlds is defined by the information the speaker has about John. Assume for example that the speaker knows that John just bought a new luxury car and has rented a huge apartment. The speaker also knows that John is an honest person with a humble family background and doesn't play the lottery. The set of accessible worlds is then the set of worlds in which all these propositions which the speaker knows about John are true.  The notions of necessity and possibility are then defined along the following lines: A proposition "p" follows necessarily from the set of accessible worlds, if all accessible worlds are part of "p" (that is, if "p" is true in all of these worlds). Applied to the example in (2) this would mean that in all the worlds which are defined by the speaker's knowledge about John, it is the case that John earns a lot of money (assuming there is no other explanation for John's wealth).  In a similar way a proposition "p" is possible according to the set of accessible worlds (i.e. the modal base), if some of these worlds are part of "p".

Ways of expressing modality.

Verbal morphology.

In many languages modal categories are expressed by verbal morphology – that is, by alterations in the form of the verb. If these verbal markers of modality are obligatory in a language, they are called "mood" markers. Well-known examples of moods in some European languages are referred to as subjunctive, conditional and indicative as illustrated below with examples from French, all three with the verb "avoir" ‘to have’. As in most Standard European languages, the shape of the verb conveys not only information about modality, but also about other categories such as person and number of the subject.  An example for a non-European language with a similar encoding of modality is Manam. Here, a verb is prefixed by a morpheme which encodes number and person of the subject. These prefixes come in two versions, one "realis" version and one "irrealis" version. Which one is chosen depends on whether the verb refers to an actual past or present event (realis), or merely to a possible or imagined event (irrealis).

Auxiliaries.

Modal auxiliary verbs, such as the English words "may, can, must, ought, will, shall, need, dare, might, could, would," and "should", are often used to express modality, especially in the Germanic languages.

Lexical expression.

Verbs such as "want" can be used to express modality lexically, as can adverbs.

Other.

Complementizers (e.g. Russian) and conjunctions (e.g. Central Pomo) can be used to convey modality.

Modal categories.

Many different kinds of modal interpretations have been observed and studied, resulting in a variety of typologies. What follows below is one of the many ways that modality has been classified. Only broad categories have been distinguished below: the reader is referred to the main articles and the references for more detailed discussions.

Realis vs. irrealis.

The closely related realis, declarative, and evidential moods refer to situations that actually exist, are claimed to exist, or are inferred to exist. In contrast, irrealis moods refer to situations that are not known to exist. Two common irrealis moods are the conditional mood, stating what would happen under a certain condition or conditions (expressed periphrastically in English as "would" + main verb), and the subjunctive mood, stating the speaker's preferences for what should occur (such as "he leave" in the English "I demand that he leave") or hypotheticals (such as English "If I were to go...").  Counterfactuals refer to things that are contrary to the actual situation. In English, counterfactuals can be expressed implicitly in "if"-clauses by using a tense form that normally refers to a time prior to the time actually semantically referred to in the "if"-clause. For example, "If I knew that, I wouldn't have to ask" contains the counterfactual "If I knew", which refers to the present tense despite the form of the verb, and which denies the proposition "I know that". This contrasts with the construction "If I know that...", which is not a counterfactual because it means that maybe I know it and maybe I don't (or maybe I will know it, and maybe I will not). Likewise, "If I had known that, I would have gone there" contains the counterfactual "If I had known", denying the proposition that I had known.

Epistemic vs. deontic modality.

Epistemic modals are used to indicate the possibility or necessity of some piece of knowledge. It deals with the likelihood of the actualization of the state of affairs. In the epistemic use, modals can be interpreted as indicating inference or some other process of reasoning involved in coming to the conclusion stated in the sentence containing the modal. However, epistemic modals do not necessarily require inference, reasoning, or evidence. One effect of using an epistemic modal (as opposed to not using one) is a general weakening of the speaker's commitment to the truth of the sentence containing the modal. However, it is disputed whether the function of modals is to indicate this weakening of commitment, or whether the weakening is a by-product of some other aspect of the modal's meaning.  Examples of the expression of epistemic modality in English are: "he might be there" (low probability, substantial doubt), "He may be there" (possibility), "He should be there by now" (high probability), and "He must be there by now" (certitude, no doubt).  In contrast, deontic modality is concerned with possibility and necessity in terms of freedom to act (including ability, permission, and duty). In other words, deontic modals state something about the desirability of the actualization of the state of affairs, expressed in varying degrees of obligation. English examples include "She can go" (ability), "You may go" (permission), "You should go" (request), and "You must go" (command). In English as in many other languages, some of the same words are used for deontic modality as for epistemic modality, and the meaning is distinguished from context: "He must be there by now" (epistemic) versus "He must be there tomorrow at noon" (deontic).

Ability, desirability, permission, obligation, and likelihood.

Ability, desirability, permission, obligation, and probability can all be exemplified by the usage of auxiliary modal verbs in English:

In linguistics, modality is a system of linguistic options that allows for expressing a speaker's general intentions (or illocutionary point) as well as the speaker's belief as to whether the proposition expressed is true, obligatory, desirable, or actual. Modal options can be realized by word order (moods), modal auxiliaries and modal adjuncts.

情态(英语:modality)是一个语法学术语,是用来体现说话者对其所言的主观态度的句法语义范畴。


Structure.

Cratons have thick lithospheric roots. Mantle tomography shows that cratons are underlain by anomalously cold mantle corresponding to lithosphere more than twice the typical thickness of mature oceanic or non-cratonic, continental lithosphere. At that depth, craton roots extend into the asthenosphere. Craton lithosphere is distinctly different from oceanic lithosphere because cratons have a neutral or positive buoyancy, and a low intrinsic isopycnic density. This low density offsets density increases due to geothermal contraction and prevents the craton from sinking into the deep mantle. Cratonic lithosphere is much older than oceanic lithosphere—up to 4 billion years versus 180 million years.  Rock fragments (xenoliths) carried up from the mantle by magmas containing peridotite have been delivered to the surface as inclusions in subvolcanic pipes called kimberlites. These inclusions have densities consistent with craton composition and are composed of mantle material residual from high degrees of partial melt. Peridotite is strongly influenced by the inclusion of moisture. Craton peridotite moisture content is unusually low, which leads to much greater strength. It also contains high percentages of low-weight magnesium instead of higher-weight calcium and iron. Peridotites are important for understanding the deep composition and origin of cratons because peridotite nodules are pieces of mantle rock modified by partial melting. Harzburgite peridotites represent the crystalline residues after extraction of melts of compositions like basalt and komatiite.

Formation.

The process by which cratons were formed from early rock is called cratonization. The first large cratonic landmasses formed during the Archean eon. During the early Archean, Earth's heat flow was nearly three times higher than it is today because of the greater concentration of radioactive isotopes and the residual heat from the Earth's accretion. There was considerably greater tectonic and volcanic activity; the mantle was less viscous and the crust thinner. This resulted in rapid formation of oceanic crust at ridges and hot spots, and rapid recycling of oceanic crust at subduction zones. There are at least three hypotheses of how cratons have been formed: 1) surface crust was thickened by a rising plume of deep molten material, 2) successive subducting plates of oceanic lithosphere became lodged beneath a proto-craton in an under-plating process, 3) accretion from island arcs or continental fragments rafting together to thicken into a craton.  Earth's surface was probably broken up into many small plates with volcanic islands and arcs in great abundance. Small protocontinents (cratons) formed as crustal rock was melted and remelted by hot spots and recycled in subduction zones.  There were no large continents in the early Archean, and small protocontinents were probably the norm in the Mesoarchean because they were prevented from coalescing into larger units by the high rate of geologic activity. These felsic protocontinents (cratons) probably formed at hot spots from a variety of sources: mafic magma melting more felsic rocks, partial melting of mafic rock, and from the metamorphic alteration of felsic sedimentary rocks. Although the first continents formed during the Archean, rock of this age makes up only 7% of the world's current cratons; even allowing for erosion and destruction of past formations, evidence suggests that only 5 to 40 percent of the present continental crust formed during the Archean.  One perspective of how the cratonization process might have first begun in the Archean is given by Warren B. Hamilton: Very thick sections of mostly submarine mafic, and subordinate ultramafic, volcanic rocks, and mostly younger subaerial and submarine felsic volcanic rocks and sediments were oppressed into complex synforms between rising young domiform felsic batholiths mobilized by hydrous partial melting in the lower crust. Upper-crust granite-and-greenstone terrains underwent moderate regional shortening, decoupled from the lower crust, during compositional inversion accompanying doming, but cratonization soon followed. Tonalitic basement is preserved beneath some greenstone sections but supracrustal rocks commonly give way downward to correlative or younger plutonic rocks... Mantle plumes probably did not yet exist, and developing continents were concentrated in cool regions. Hot-region upper mantle was partly molten, and voluminous magmas, mostly ultramafic, erupted through many ephemeral submarine vents and rifts focussed at the thinnest crust... Surviving Archean crust is from regions of cooler, and more depleted, mantle, wherein greater stability permitted uncommonly thick volcanic accumulations from which voluminous partial-melt, low-density felsic rocks could be generated.

Erosion.

The long-term erosion of cratons has been labelled the "cratonic regime". It involves processes of pediplanation and etchplanation that lead to the formation of flattish surfaces known as peneplains. While the process of etchplanation is associated to humid climate and pediplanation with arid and semi-arid climate, shifting climate over geological time leads to the formation of so-called polygenetic peneplains of mixed origin. Another result of the longevity of cratons is that they may alternate between periods of high and low relative sea levels. High relative sea level leads to increased oceanicity, while the opposite leads to increased inland conditions.  Many cratons have had subdued topographies since Precambrian times. For example, the Yilgarn Craton of Western Australia was flattish already by Middle Proterozoic times and the Baltic Shield had been eroded into a subdued terrain already during the Late Mesoproterozoic when the rapakivi granites intruded.

A craton (,, or ; from "kratos" "strength") is an old and stable part of the continental lithosphere, which consists of the Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep lithospheric roots that extend as much as several hundred kilometres into the Earth's mantle.

克拉通(来自希腊语"kratos",意为“强度”),或称稳定地块、大陆核心、古陆、古陆核、刚块、安定地块,是指大陆地壳上的古老而稳定的部分,于最近至少5亿年内的大陆和超大陆的会聚和分裂过程中几乎没有发生变化。有些克拉通甚至在20亿年前或更早就形成了。克拉通一般都存在于大陆内部,由古代的结晶基底构成,这些基岩的成分主要是小比重的长英质火成岩如花岗岩。克拉通内的地壳较厚,并有深根插入地幔,可达200公里深处。


History.

The idea of constructing a man-made waterway through Central America has been thought about throughout history. The colonial administration of New Spain conducted preliminary surveys. The routes suggested usually ran across Nicaragua, Panama, or the Isthmus of Tehuantepec in Mexico.  The history of attempts to build a Nicaragua canal connecting the Caribbean Sea and thus the Atlantic Ocean and the Pacific Ocean goes back at least to 1825 when the Federal Republic of Central America hired surveyors to study a route via Lake Nicaragua, above sea level. Many other proposals have followed. Despite the operation of the Panama Canal, which opened in 1914, interest in a Nicaragua canal has continued. With emergence of globalization, an increase in commerce and the cost of fuel, and the limitations of the Panama Canal, the concept of a second canal across the American land bridge became more attractive, and in 2006 the president of Nicaragua, Enrique Bolaños, announced an intention to proceed with such a project. Even with the Panama Canal expansion project, which began commercial operation to modern New Panamax vessels on 26 June 2016, some ships would be too big for the Panama Canal.  On 26 September 2012, the Nicaraguan Government and the newly formed Hong Kong Nicaragua Canal Development Group (HKND) signed a memorandum of understanding that committed HKND to financing and building the "Nicaraguan Canal and Development Project". HKND Group is a private enterprise.  The Nicaraguan government subsequently approved the "Master Concession Agreement" with HKND on 13 June 2013 thereby granting "the sole rights to the HKND Group to plan, design, construct and thereafter to operate and manage the Nicaragua Grand Canal and other related projects, including ports, a free trade zone, an international airport and other infrastructure development projects." The agreement would have lasted for 50 years and was renewable for another 50 years. HKND would have paid the Government of Nicaragua US$10M annually for 10 years, and thereafter a portion of the revenue starting at 1% and increasing later. Stratfor indicated that after 10 years, ownership shares would periodically be handed over to Nicaragua, so that after 50 years Nicaragua would be the majority shareholder.  HKND Group performed a preliminary study phase of development to assess the technological and economic feasibility of constructing a canal in Nicaragua, as well as the potential environmental, social, and regional implications of various routes. The canal and other associated projects would be financed by investors throughout the world and would generate jobs for Nicaragua and other Central American countries.  Initial findings of the commercial analysis conducted by HKND Group indicate that the combined effect of growth in east–west trade and in ship sizes could provide a compelling argument for the construction of a second canal, substantially larger than the expanded Panama Canal, across Central America. In the 2020s, growth in global maritime trade is expected to cause congestion and delays in transit through the Panama Canal without a complementary route through the isthmus, and by 2030, the volume of trade that a Nicaragua Canal could serve would have grown by 240%.  On 10 June 2013, The Associated Press reported that the National Assembly's Infrastructure Committee voted nearly unanimously in favor of the project, with four members abstaining. On 13 June, Nicaragua's legislature passed the legislation granting the concession. On 15 June, Nicaraguan President Daniel Ortega and the billionaire chairman of HKND Group, Wang Jing, signed the concession agreement giving HKND Group the rights to construct and manage the canal and associated projects for 50 years. An HKND Group press release read, "HKND Group Successfully Obtains Exclusive Right to Develop and Manage Nicaragua Grand Canal for 100 Years." Under the exclusive contract, Wang can skip building the canal (and making any payments to Nicaragua) and instead simply operate lucrative tax-free side projects.  Wang announced at a press briefing in June 2013 that he had successfully attracted global investors to the $40 billion project. In January 2014, Wang and President Ortega issued a statement that the project's construction would begin in December 2014, and that it would be completed in 2019.  On 7 July 2014, a route for the Nicaragua Canal was approved. The route starts from the mouth of the Brito River on the Pacific side, passes through Lake Nicaragua, and ends in the Punta Gorda River on the Caribbean. The proposed canal would be between 230 meters and 520 meters (754.6 feet and 1,706 feet) wide and deep. The "Toronto Star" noted that Chinese engineer Dong Yung Song said the canal's design called for the creation of a artificial lake. The water to fill the canal's giant locks would come from the artificial lake, not from Lake Nicaragua.  Daniel Ortega whose government approved the agreement within one week in June 2013, reportedly perceived the canal as the second phase of the Nicaraguan Revolution, predicting that it would pull Nicaragua out of poverty and lead to the creation of 250,000 jobs, but HKND said the project would create 50,000 jobs, though about half would come from abroad, mainly China.  "The Moscow Times" reported in 2014 that Russia was willing to help build the Nicaragua Canal, viewing the project in part as an opportunity to pursue strategic interests in the region. Construction was to begin on 29 December 2014, and officially started a week earlier. However, owing to Nicaragua's volatile climate and seismic activity, feasibility concerns emerged over the project's future. In November 2015, HKND announced that there would be a delay in the construction of locks and excavations until late 2016 in order to fine-tune the design.  The Nicaragua canal project saw business rivalry greatly intensify in late 2014. China Harbor Engineering Company, an experienced construction company, offered to design, construct, and finance a fourth set of locks in Panama, where it opened a regional headquarters. If built to the width of the proposed Nicaragua Canal, it would cut across far fewer kilometers, and still cost only $10 billion, according to the firm. Panama is in a much better financial situation than Nicaragua to afford taking on such debt and already has a stream of income from its existing canals.  Alternative motives have been explored and other projects have taken priority against the water transportation venture. Bloomberg reported in 2015 that "conspiracy theories abound" including the project was a land grab by Ortega, an attempt by Ortega to "whip up" support in elections, and part of a Chinese plan to gain influence in the region.  By November 2016, the president of the canal commission, Manual Coronel Kautz said "According to our schedule, we should initiate major works by the end of the year." However, Carlos Fernando Chamorro, editor of the Confidencial newspaper, said "If the People's Republic of China does not step forward, it won't happen. Wang Jing does not have the reputation to push this through. If it is just him, then the chances of this happening are zero. If the PRC steps in, then it is a big possibility."  Following financial difficulties, HKND finally closed its Headquarters offices in China in April 2018, leaving no forwarding address or telephone numbers to be reached.

Opposition.

Protests against the canal's construction occurred shortly after the official ceremony marking its beginning. Farmers feared it could cause their eviction and land expropriation.  Opposition leader Eliseo Nuñez has called the deal "part of one of the biggest international scams in the world". Legal challenges that the deal violates constitutional rights were rejected by the Supreme Court of Nicaragua and a retrospective rewriting of the Constitution of Nicaragua placed HKND beyond legal challenge. HKND has been granted the right to expropriate land within on each side of the canal and pay only cadastral value, not market value, for property. Wang, however, promised to pay fair market value. The estimates of the number of people who would be displaced range from 29,000 to more than 100,000. There are indications of local opposition to intended expropriations. Thus, according to an activist leader, an unrest in Rivas in December 2014, in opposition to the canal, left two protesters dead, although no evidence was ever produced to justify his claim. The CIDH, Nicaragua's Human Rights Commission, has strongly criticized the government for not looking into the project's effect on citizens, amid claims that citizens were not involved in decision-making. The British firm ERM, who carried out the Environmental Impact Assessment, claims it held consultations with around 6,000 people in the communities along its planned route, and estimated that the property of about 30,000 people would be affected. National opinion polls show that support for the project is about 70%.

Reported end to the canal project.

Investor Wang had financial setbacks unrelated to the Nicaragua project, losing 80% of his net worth during the 2015–16 Chinese stock market turbulence. In March 2017, the "Havana Times" reported that the public relations agency handling Wang's interests in Nicaragua had been let go, in absence of any developments on the project to report, and Wang had not been in the country in more than two years. In May 2017, the "PanAm Post" indicated that "no concrete action has been taken to begin the project" and suggested that the project was either "paralyzed, or nonexistent." In September 2017 Agence France-Presse reported that the work had been "pushed back indefinitely," although the government renewed the project's environmental permit in April 2017.  In February 2018, Manuel Coronel Kautz, head of Interoceanic Grand Canal Authority of Nicaragua, told Agence France Presse work on the canal was still ongoing, but by that point analysts and activists widely viewed the canal project as defunct, with China having shifted its investment focus to Panama, the main competitor to a Nicaraguan canal. Following financial difficulties, HKND finally closed its offices in April 2018, leaving no forwarding address or telephone numbers to be reached. Absent a 60% vote to revoke the legislation, HKND maintains the legal concessions established by the 2013 law, including for other infrastructures projects in Nicaragua, including ports, roads, railway and an airport.

Description.

The construction company provided a project description for review on open source, dated December 2014. The canal as planned would have been and would have three sections. The West Canal runs from Brito on the Pacific Ocean up the Rio Brito valley, crosses the continental divide, and after passing through the Rio Las Lajas valley enters Lake Nicaragua; its length would be. The Nicaragua Lake section measures and runs from south of San Jorge to south of San Miguelito. The Eastern Canal would be the longest section at and would be built along the Rio Tule valley through the Caribbean highland to the Rio Punta Gorda valley to meet the Caribbean Sea. A channel would have to be dug in the lake bottom, as it is not deep enough for large vessels to transit the canal.  Both the West Canal and the East Canal would each have one lock with 3 consecutive chambers to raise ships to the level of Lake Nicaragua that has an average water elevation of 31.3 m, range 30.2–33.0 m. The western Brito Lock would be inland from the Pacific, and the eastern Camilo Lock would be inland from the Caribbean Sea. The dimensions of each of the locks' chambers are long, wide, and threshold depth. As locks generally define the limit on the size of ships that can be handled, the Nicaragua Canal would have allowed passage for larger ships than those that pass through the Panama Canal. For comparison, the new third set of locks in the Panama expansion will only be long, wide, and deep.  No water from Lake Nicaragua was planned to be used to flood the locks; water would have come from local rivers and recycling using water-saving basins. The Camilo lock would have been built adjacent to a new dam of the upper Punta Gorda River that creates a reservoir. This Atlanta Reservoir (or Lake Atlanta) would have a surface area of 395 km. West of the Atlanta reservoir, the Rio Agua Zarca would have been dammed to create a second reservoir. This reservoir would have had a surface area of 48.5 km and hold 1,100 gigalitres. A hydropower facility would be built at the dam and would have generated over 10 megawatts of power to be used for Camilo Lock operations. Both locks would also be connected to the country's power grid and have back-up generator facilities. It was estimated that each lock would have used about 9 megawatts of power.  At each oceanic canal entrance, breakwaters and port facilities would have been constructed. The Pacific port would be named Brito Port and the Caribbean one Aguila Port. Initially these two ports would have helped during construction and later become international ports. Their design capacity was 1.68 million TEU/year and 2.5 million TEU/year, respectively. Existing port facilities at Corinto and Bluefields would have been improved to allow for shipment of material to the entry ports under construction. Fuel storage sites would be placed at the two port sites. Four lighthouses would be constructed at the entrances to the East and West Canals. In addition, the channel entrance on sea would have been be marked on both sides with a large sailing buoy about offshore and 2 light buoys would mark the passage through Lake Nicaragua.  A free trade zone with commercial facilities as well as tourist hotels and an international airport at Rivas were planned to be built when canal construction was advanced.  Appropriate road improvements were planned. The Pan-American Highway would have crossed the canal via a bridge. Nicaragua Route 25 (Acoyapa-San Carlos) on the eastern side of Lake Nicaragua would have gotten a ferry service. Both ports would get public road connections. HKND plans to construct a private gravel maintenance road on both sides of the canal.  The estimate for the workforce in 2020 was 3,700 people, and 12,700 in 2050 when traffic had increased.  Transit time would have been about 30 hours. It was projected that by 2020 3,576 ships would have transited the canal annually. The transit rate was expected to increase to 4,138 by 2030, and to 5,097 by 2050. For comparison, the Panama Canal handled 12,855 transits in 2009.

Construction.

No significant construction took place. No "major works" such as dredging were planned to take place until after a Pacific Ocean wharf was built.  The apparent lack of experience of Wang and his HKND Group in large-scale engineering was cited as a risk.  On December 22, 2014, Wang announced construction started in Rivas, Nicaragua. Wang spoke during the starting ceremony of the first works of the Interoceanic Grand Canal in Brito town. Construction of the new waterway would have been by HKND Group—Hong Kong–based HK Nicaragua Canal Development Investment Co Ltd., which is controlled by Wang. According to HKND's announced plans in 2015, the project entailed the canal's development and building, and a supporting infrastructure. There would have been four main phases. The preconstruction phase included getting permits, acquiring land and machinery, and finalizing designs and plans. The early construction phase, started in December 2014, lasted through September 2015; it secured access to construction sites, but it did not provide the critical infrastructure nor mobilized the workforce. During the construction phase from September 2015 to March 2020, the canal would have been dug and the locks built along with accompanying infrastructure. The commissioning phase projected from April 2020 to June 2020 included lock testing and lock and tug boat operator training.  HKND described the project as the largest civil earth-moving operation in history. Most of this would have consisted of dry excavation to form the canal with an estimate of 4,019 million cubic metres of rock and soil. There would have been 739 MCM of freshwater dredging (Lake Nicaragua) and 241 MCM of marine dredging. Marine dredging of the oceanic access canal would be required on the Pacific side for 1.7 km and on the Caribbean Sea for 14.4 km. Disposal of excavation material would have been done along the canal in designated disposal areas typically within 3 km of the canal.  Two concrete plants and a steel plant were planned to support the project. While cement would have likely been imported, construction aggregate would have come from local quarries near the two locks.  HKND estimates that about 50,000 people would be employed during the five-year construction, about half of them from Nicaragua, 25% from China, and the remainder from various other countries. 1,400 workers would be in office or administrative positions and the rest in the field. The management offices would be rented or purchased near Rivas. Workers would live in one of nine camps, which besides food and shelter would also provide health care and security. These are “closed” camps—that is, workers cannot leave the camp unless part of an organized activity. The work schedule calls for 12-hour shifts for seven days a week. Domestic workers work two weeks and get one week off, while foreign workers are six weeks on and get two weeks off (management) or 22 weeks on, four weeks off (blue collar workers).  On 2 September 2015, Pang Wai Kwok (executive VP of HKND Group) was interviewed by Nicaraguan journalist Carlos Solis and said up to 3,000 people might be employed on the canal project within the year. However, the labor force depends on the contract bid's winner and Kwok said anyone in the world is eligible to work on the canal.

Financing.

Project costs were estimated in the region of $40 billion to $50 billion Beside private money provided by Wang at the start-up, further influx of financial support was expected from investors. An IPO was reported to be in preparation by the end of 2014. XCMG, a state-owned Chinese construction company would have provided machinery and take 1.5% to 3% of HKND shares in return.  By the end of 2014, no major investors had been named. There had been speculation that the Chinese government would provide financial backing for the project, but China, as well as Wang, denied this. Wang lost nearly 85% of his wealth during the 2015 Chinese stock market crash, according to the Bloomberg Billionaires Index. In addition, Wang has had a string of setbacks for projects around the world since 2014. The economic development potential for the canal project is relatively measurable with Panama; however, the World Bank describes the country of Nicaragua as the second poorest in Latin America and the Caribbean. The World Bank has compiled a data list of projects that the impoverished nation has on record and the majority of the efforts are geared towards infrastructure and agricultural needs, but there is no explicit title project that would support the canal line of effort.  Wang admitted that the project has financial, political, and engineering risks. With the high cost of the project that independently has been estimated to be about $100 billion, it was not fully funded. The project was expected in 2014 to be completed in 2020, but Stratfor, an analyst agency, stated then that was an "unrealistic goal."  While the Nicaraguan National Bank reserves served as collateral on the part of Nicaragua, HKND had no such potential liability.  Following financial difficulties, HKND finally closed its Headquarter offices in China in April 2018, leaving no forwarding address or telephone numbers to be reached.

Impact.

Environmental.

Some of the natural habitat of at least 22 endangered species would be destroyed in the construction. Another major environmental concern is the project's impact on Lake Nicaragua, the largest source of freshwater in Nicaragua. An oil spill would have serious and lasting consequences. Other problems include the possibility of dredging bringing up toxic sediments, the disruption of migration patterns of animal species, and the potential to introduce invasive species to the Lake. Environmental studies had not been released by HKND when the project officially started in December 2014. The Nicaraguan Academy of Sciences noted that hundreds of thousands of hectares of pristine forests and wetlands would be destroyed and pointed out that the environmental study performed for the canal was not independent.  President Daniel Ortega stated that he is "not concerned about harming the lake because it is already contaminated." Protesters fear that the canal would bring massive environmental destruction to Lake Nicaragua and the Atlantic Autonomous Regions. 400,000 hectares of tropical rain forest and wetlands would be destroyed. It would also encroach upon the habitats of animals such as Baird's tapir, the spider monkey, and the jaguar.

Safety.

Richard Condit, from the Smithsonian Tropical Research Institute, believes that the project could be used as leverage for forest protection in a country that currently lacks "institutional capacity" to meet conservation needs. A Canadian pilot was the first fatality during the canal project. Atkinson was flying alone on the western side of Lake Nicaragua during an aerial survey.

Sustainability.

The survey site was on the same side as NicarAgua–Dulce, which is the only ecotourism group in Nicaragua that is affiliated with The International Ecotourism Society, and it is located north of the proposed canal site. Falling in line with ecotourism, Nicaragua's Ministry of Environment and Natural Resources has promoted formal workshops at each level of education (primary, secondary, and post-secondary); however, there is no curriculum relevant to the pending canal project. The American-led Foundation for Sustainable Development is another partner that provides training initiatives to Nicaraguans that cannot access formal education. One of FSD's support sites is located at Tola, which is within close proximity of the proposed Brito–Pacific canal opening.

Economic.

As the original Panama Canal still has capacity for Panamax-sized shipping and Panama has completed its Panama Canal expansion project, adding more capacity and allowing transit for even larger New Panamax size ships, projections for the Nicaragua canal's traffic may be optimistic. While the proposed Nicaragua Canal would be wide enough to accommodate Triple E class of mega container ships, which are too wide for the expanded Panama Canal, few ports are able to handle these ships at the present. Further, a coast-to-coast railway line may be built by China in Honduras and could affect utilization of the Nicaragua Canal. Also, North American land bridges in Mexico and the United States will compete in the traffic between Asia and the U.S. east coast. Thus, competition may undermine the Nicaragua Canal's economic viability if it was ever built.  The canal would affect neighboring economies, like Honduras and El Salvador, as they are part of the commercial treaty known as North Triangle of Central America (Triángulo Norte de Centroamérica). The GDP of each nation would be influenced by expanded export/import operations and trade cooperation through agencies like the promotion authority in El Salvador.

Social.

According to the official Environmental Impact Assessment carried out by ERM, the canal would require the relocation of around 30,000 people. However, according to human rights group Amnesty International it would "forcibly displace an estimated 120,000 people, including Rama and Creole communities from protected indigenous territories on the Caribbean coast." The report claims that communities established in the area of canals have been visited by foreigners, guarded by Nicaraguan authorities, measuring the lands of the inhabitants, and that laws passed by the Ortega government "authorizes HKND to expropriate whatever land it wants, while denying displaced families the right to appeal." Amnesty International also states that excessive forces and unjust arrests have been performed by Nicaraguan officials. However, the 2015 Nicaraguan government's report on the canal states: "The Nicaraguan government and HKND will guarantee that persons and families on the route of the canal's construction will have living conditions superior to those they currently have [without the canal]."

The Nicaraguan Canal (), formally the Nicaraguan Canal and Development Project (also referred to as the Nicaragua Grand Canal, or the Grand Interoceanic Canal) was a proposed shipping route through Nicaragua to connect the Caribbean Sea (and therefore the Atlantic Ocean) with the Pacific Ocean. Scientists were concerned about the project's environmental impact, as Lake Nicaragua is Central America's key freshwater reservoir while the project's viability was questioned by shipping experts and engineers.

尼加拉瓜运河为规划中的横跨尼加拉瓜的跨洋运河,它与巴拿马运河一样连接大西洋与太平洋,为海路运输节省时间。运河预计由尼加拉瓜西海岸的布里托(Brito)河口,横跨尼加拉瓜湖,至东部加勒比沿岸的蓬塔戈尔达(Punta Gorda)河,总长278公里,深度27.6米,宽度从230米到520米不等。


Rules and customs.

The court for jai alai consists of walls on the front, back and left, and the floor between them. If the ball (called a "pelota", "ball" in Standard Basque) touches the floor outside these walls, it is considered out of bounds. Similarly, there is also a border on the lower of the front wall that is also out of bounds. The ceiling on the court is usually very high, so the ball has a more predictable path. The court is divided by 14 parallel lines going horizontally across the court, with line 1 closest to the front wall and line 14 the back wall. In doubles, each team consists of a frontcourt player and a backcourt player. The game begins when the frontcourt player of the first team serves the ball to the second team. The winner of each point stays on the court to meet the next team in rotation. Losers go to the end of the line to await another turn on the court. The first team to score 7 points (or 9 in Superfecta games) wins. The next highest scores are awarded "place" (second) and "show" (third) positions, respectively. Playoffs decide tied scores.  A jai alai game is played in round robin format, usually between eight teams of two players each or eight single players. The first team to score 7 or 9 points wins the game. Two of the eight teams are in the court for each point. The server on one team must bounce the ball behind the serving line, then with the cesta "basket" hurl it towards the front wall so it bounces from there to between lines 4 and 7 on the floor. The ball is then in play. The ball used in jai alai is hand crafted and consists of metal strands tightly wound together and then wrapped in goat skin. Teams alternate catching the ball in their (also hand crafted) cesta and throwing it "in one fluid motion" without holding or juggling it. The ball must be caught either on the fly or after bouncing once on the floor. A team scores a point if an opposing player:  The team scoring a point remains in the court and the opposing team rotates off the court to the end of the list of opponents. Points usually double after the first round of play, once each team has played at least one point. When a game is played with points doubling after the first round, this is called "Spectacular Seven" scoring.  The players frequently attempt a "chula" shot, where the ball is played off the front wall very high, then reaches the bottom of the back wall by the end of its arc. The bounce off the bottom of the back wall can be very low, and the ball is very difficult to return in this situation.  Since there is no wall on the right side, all jai alai players must play right-handed (wear the cesta on their right hand), as the spin of a left-handed hurl would send the ball toward the open right side.  The Basque Government promotes "jai alai" as "the fastest sport in the world" because of the speed of the ball. The sport once held the world record for ball speed with a 125–140 g ball covered with goatskin that traveled at, performed by José Ramón Areitio at the Newport, Rhode Island Jai Alai, until it was broken by Canadian 5-time long drive champion Jason Zuback on a 2007 episode of Sport Science with a golf ball speed of.  The sport can be dangerous, as the ball travels at high velocities. It has led to injuries that caused players to retire and fatalities have been recorded in some cases.

Industry.

Jai alai is a popular sport within the Latin American countries and the Philippines from its Hispanic influence. It was one of the two gambling sports from Europe, the other being horse racing, in the semi-colonial Chinese cities of Shanghai and Tianjin, and was shut down after the communist victory there. The jai alai arena in Tianjin's former Italian Concession was then confiscated and turned into a recreation center for the city's working class.

The Philippines.

Jai alai was played in Manila at the Manila Jai Alai Building, one of the most significant Art Deco buildings in Asia, which was torn down in 2000 by the Manila city government. In 1986, jai alai was banned in the Philippines because of problems with game fixing. However, jai alai returned to the Philippines in March 2010. In 2011, jai-alai was briefly shut down in the province of Pangasinan because of its connection to illegal jueteng gambling but was reopened after a court order.

United States.

In the United States, jai alai enjoyed some popularity as a gambling alternative to horse racing, greyhound racing, and harness racing, and remains popular in Florida, where the game is used as a basis for Parimutuel betting at six frontons throughout the state: Dania Beach, Fort Pierce, Jasper, Casselberry, Miami, and Reddick.  The first jai alai fronton in the United States was located in St. Louis, Missouri, operating around the time of the 1904 World's Fair. The first fronton in Florida opened at the site of Hialeah Race Course near Miami (1924). The fronton was relocated to its present site in Miami near Miami International Airport. Year-round jai alai operations include Miami Jai-Alai Fronton (the biggest in the world with a record audience of 15,502 people on 27 December 1975) and Dania Jai Alai. Seasonal facilities are Fort Pierce Jai Alai, Ocala Jai Alai and Hamilton Jai Alai. The Tampa Jai Alai operated for many years before closing in the late 1990s. Inactive jai alai permits are located in Tampa, Daytona Beach, West Palm Beach, and Quincy. One Florida fronton, in Melbourne, was converted from jai alai to greyhound racing.  By contrast, jai alai's popularity in the northeastern and western United States waned as other gambling options became available. In Connecticut, frontons in Hartford and Milford permanently closed, while the fronton in Bridgeport was converted to a greyhound race track. In 2003, the fronton at Newport Jai Alai in Newport, Rhode Island was converted into Newport Grand, a slot machine and video lottery terminal parlor, which closed permanently in August 2018. Jai alai enjoyed a brief and popular stint in Las Vegas with the opening of a fronton at the MGM Grand Hotel and Casino; however, by the early 1980s the fronton was losing money and was closed by MGM Grand owner Kirk Kerkorian. The MGM Grand in Reno also showcased jai alai for a very short period (1978–1980).  After the 1968 season, players returned home and threatened not to come back unless the owners improved their work conditions. The owners, however, offered the same terms and started hiring inexperienced players instead of the world-class stars. The public did not notice the change. Later strikes were placated with salary rises. In 1988–1991, the "International Jai-Alai Players Association" held the longest strike in American professional sport. The owners substituted with Americans raised locally, while the strikers picketed the courts for years. The players, 90% Basques, felt insecure submitted to the will of their employers. Spain was no longer a poor conservative country and the new generation of players were influenced by leftist Basque nationalism. The strike ended with an agreement between the parts. Meanwhile Native American casinos and state lotteries had appeared as an alternative to jai-alai betting. In an effort to prevent the closure of frontons in Florida, the Florida State Legislature passed HB 1059, a bill that changed the rules regarding the operation and wagering of poker in a Pari-Mutuel facility such as a jai alai fronton and a greyhound and horseracing track. The bill became law on August 6, 2003. However, while in the 50s to the 80s a game had 5,000 spectators, nowadays it does not go beyond 50.  Although the sport has been in decline in America for several years, the first public amateur jai alai facility was built in the United States in 2008, in St. Petersburg, Florida, with the assistance of the city of St. Petersburg and private funding from Jeff Conway (Laca). Jai alai is virtually unknown in the western United States but still maintains some popularity in parts of the Northeast.

Amateur jai-alai.

In addition to the amateur court in St. Petersburg, The American Jai-Alai Foundation offers lessons. Its president, Victor Valcarce, was a pelotari at Dania Jai-Alai (MAGO #86) and was considered the best "pelota de goma" (rubber ball) player in the world. Sponsored in North Miami Beach, Florida which was once owned by World Jai-Alai as a school that, in 1972, produced the greatest American pelotari, Joey Cornblit #37.  During the late 1960s, in addition to North Miami Amateur, there was at least one other amateur court from International Amateur Jai-Alai in South Miami professional players that emerged including "RANDY" #44 at World Jai-Alai, regarded as the first American pelotari who turned pro in 1968 and enjoyed a lengthy career. In the 1970s and early 1980s Orbea's Jai-Alai in Hialeah featured four indoor courts. Two of the courts played with hard rubber balls ("pelota de goma") were shorter than a standard court (75' / 90') and used for training players and amateur leagues. There were also two courts played with the regulation pelota (hardball / "pelota dura"), one short in length (115') and one regulation length (150'). Orbea's also sold equipment such as cestas and helmets.  Retired players visited and played as well as highly skilled amateurs, pros from Miami Jai-Alai and various other professional frontons operating at the time. What the South Miami, North Miami, Orbea and later the Milford amateur courts contributed to what is thought to be the golden age of the amateur jai-alai player and the sport in the United States is impressive. In the late 1980s at least one other amateur court was constructed in Connecticut.  At Dania Jai Alai, there is a "Hall of Fame" to document the best front and back court players.

Jai alai (: ) is a sport involving a ball that is bounced off a walled space by accelerating it to high speeds with a hand-held wicker device (cesta). It is a variation of Basque pelota. The term, coined by Serafin Baroja in 1875, is also often loosely applied to the fronton (the open-walled playing area) where the sport is played. The game is called "zesta-punta" (basket tip) in Basque. The sport is played in Spain, south west of France and Latin American countries.

壁网球(),是一种以2英寸橡胶作球心,外-{面}-包有羊皮的硬球。此项运动起源于西班牙,1930年传入中国上海。


Park history.

Pre-park.

Resource extraction on the Congaree River centered on cypress logging from 1898, when the "Santee River Cypress Logging Company" began to operate in the area of what is now the park. Owned by Francis Beidler and Benjamin F. Ferguson of Chicago, the company operated until 1914; subsequently, Beidler and his heirs retained ownership of the area. In the 1950s Harry R. E. Hampton was a member of the Cedar Creek Hunt Club and co-editor of "The State". Hampton joined with Peter Manigault at the Charleston "The Post and Courier" to advocate preservation of the Congaree floodplain. Hampton formed the Beidler Forest Preservation Association in 1961. As a result of this advocacy a 1963 study by the National Park Service reported favorably on the establishment of a national monument.

Monument establishment.

No progress was made in the 1960s. Renewed logging by the Beidlers in 1969 prompted the 1972 formation of the Congaree Swamp National Preserve Association (CSNPA). The CSNPA joined forces with the Sierra Club and other conservation organizations to promote federal legislation to preserve the tract. South Carolina Senators Strom Thurmond and Ernest F. Hollings introduced legislation in 1975 for the establishment of a national preserve. On October 18, 1976 legislation was passed to create Congaree Swamp National Monument. An expansion plan was introduced by Hollings and Thurmond in 1988, expanding the monument to.

Conversion to a national park.

Over two-thirds of the national monument was designated a wilderness area on October 24, 1988, and it became an Important Bird Area on July 26, 2001. Congress redesignated the monument Congaree National Park on November 10, 2003, dropping the misleading "swamp" from the name, and simultaneously expanded its authorized boundary by approximately. As of December 31, 2011, approximately of the park are in federal ownership.

Environment.

The park preserves a significant part of the Middle Atlantic coastal forests ecoregion. Although it is frequently referred to as a swamp, it is largely bottomland subject to periodic inundation by floodwaters.  It has been designated an old growth forest. The park also has one of the largest concentrations of champion trees in the world, with the tallest known examples of 15 species. Champion trees include a 361-point loblolly pine, a 384-point sweetgum, a 465-point cherrybark oak, a 354-point American elm, a 356-point swamp chestnut oak, a 371-point overcup oak, and a 219-point common persimmon.  Large animals possibly seen in the park include bobcats, deer, feral pigs, feral dogs, coyotes, armadillos, turkeys, and otters. Its waters contain interesting creatures like amphibians, turtles, snakes, and many types of fish, including bowfin, alligator gar, and catfish.

Amenities and attractions.

In addition to being a designated wilderness area, a UNESCO biosphere reserve, an important bird area and a national natural landmark, Congaree National Park features primitive campsites and offers hiking, canoeing, kayaking, and bird watching. The park is also a popular spot for watching firefly displays on summer evenings. Primitive and backcountry camping are available. Some of the hiking trails include the Bluff Trail (0.7 mi), Weston Lake Loop Trail (4.6 mi), Oakridge Trail (7.5 mi), and King Snake Trail (11.1 mi) where hikers may spot deer, raccoon, opossum, and even bobcat tracks. The National Park Service rangers have current trail conditions which can be found in the Harry Hampton Visitor Center. Along with hiking trails, the park also has a marked canoe trail on Cedar Creek.  Most visitors to the park walk along the Boardwalk Loop, an elevated walkway through the swampy environment that protects delicate fungi and plant life at ground level. Congaree boasts both the tallest (169 ft, 51.4m) and largest (42 cubic meters) loblolly pines ("Pinus taeda") alive today as well as several cypress trees well over 500 years old. The Harry Hampton Visitor Center features exhibits about the natural history of the park, and the efforts to protect the swamp.  Monthly volunteer-led hikes are offered on some of the longer trails to give visitors an opportunity to get off the boardwalk and up close to nature.

Climate.

According to the Köppen climate classification system, the Harry Hampton Visitor Center at Congaree National Park has a Humid subtropical climate ("Cfa").

Geology.

The park resides entirely within the Congaree River Floodplain Complex with flood deposits of sand, silt, and clay. Muck and peat are the products of vegetation decay. The meander of the river has produced distinctive oxbow lakes. North of the park is the NE-SW regional trending Augusta Fault and the Terrace Complex consisting of Pliocene fluvial terraces. South of the park is the Southern Bluffs, which have been eroding since the Late Pleistocene. West of the park is the Fall Line and Piedmont.

Documentary.

In 2008, South Carolina Educational Television (SCETV) produced a documentary on the history of the Congaree National Park titled "Roots in the River: The Story of Congaree National Park". The documentary featured interviews with people involved in the movement that eventually led to the area's U.S. National Monument status, and observed the role the park plays in the surrounding community of the Lower Richland County area of South Carolina. The program first aired on the SCETV network in September 2009.

Congaree National Park is a American national park in central South Carolina. The park received its official designation in 2003 as the culmination of a grassroots campaign that began in 1969. The park preserves the largest tract of old growth bottomland hardwood forest left in the United States. The lush trees growing in its floodplain forest are some of the tallest in the eastern United States, forming one of the highest temperate deciduous forest canopies remaining in the world. The Congaree River flows through the park. About are designated as a wilderness area.

康加里国家公园保存着美国存留的最大面积的低地原始阔叶林。位于南卡罗莱纳州,面积为26,546英亩的国家公园,1969年开始的基层竞选达到顶峰时,即2003年被指认为国家公园。平原森林生长着苍翠繁茂的树木,一些是美国东部最高的,形成世界上现有温带落叶林之一。康加里河流经公园,公园约57%面积被指认为自然荒野区。


Signs and symptoms.

Cognitive aspects.

In cognitive models of social anxiety disorder, those with social phobias experience dread over how they will present to others. They may feel overly self-conscious, pay high self-attention after the activity, or have high performance standards for themselves. According to the social psychology theory of self-presentation, a sufferer attempts to create a well-mannered impression towards others but believe they are unable to do so. Many times, prior to the potentially anxiety-provoking social situation, sufferers may deliberately review what could go wrong and how to deal with each unexpected case. After the event, they may have the perception that they performed unsatisfactorily. Consequently, they will perceive anything that may have possibly been abnormal as embarrassing. These thoughts may extend for weeks or longer. Cognitive distortions are a hallmark, and are learned about in CBT (cognitive-behavioral therapy). Thoughts are often self-defeating and inaccurate. Those with social phobia tend to interpret neutral or ambiguous conversations with a negative outlook, and many studies suggest that socially anxious individuals remember more negative memories than those less distressed.  An example of an instance may be that of an employee presenting to their co-workers. During the presentation, the person may stutter a word, upon which he or she may worry that other people significantly noticed and think that their perceptions of him or her as a presenter have been tarnished. This cognitive thought propels further anxiety which compounds with further stuttering, sweating, and, potentially, a panic attack.

Behavioural aspects.

Social anxiety disorder is a persistent fear of one or more situations in which the person is exposed to possible scrutiny by others and fears that he or she may do something or act in a way that will be humiliating or embarrassing. It exceeds normal "shyness" as it leads to excessive social avoidance and substantial social or occupational impairment. Feared activities may include almost any type of social interaction, especially small groups, dating, parties, talking to strangers, restaurants, interviews, etc.  Those who suffer from social anxiety disorder fear being judged by others in society. In particular, individuals with social anxiety are nervous in the presence of people with authority and feel uncomfortable during physical examinations. People who suffer from this disorder may behave a certain way or say something and then feel embarrassed or humiliated after. As a result, they often choose to isolate themselves from society to avoid such situations. They may also feel uncomfortable meeting people they do not know, and act distant when they are with large groups of people. In some cases, they may show evidence of this disorder by avoiding eye contact, or blushing when someone is talking to them.  According to psychologist B. F. Skinner, phobias are controlled by escape and avoidance behaviors. For instance, a student may leave the room when talking in front of the class (escape) and refrain from doing verbal presentations because of the previously encountered anxiety attack (avoid). Major avoidance behaviors could include an almost pathological or compulsive lying behavior in order to preserve self-image and avoid judgement in front of others. Minor avoidance behaviors are exposed when a person avoids eye contact and crosses his/her arms to avoid recognizable shaking. A fight-or-flight response is then triggered in such events.

Physiological aspects.

Physiological effects, similar to those in other anxiety disorders, are present in social phobias. In adults, it may be tears as well as excessive sweating, nausea, difficulty breathing, shaking, and palpitations as a result of the fight-or-flight response. The walk disturbance (where a person is so worried about how they walk that they may lose balance) may appear, especially when passing a group of people. Blushing is commonly exhibited by individuals suffering from social phobia. These visible symptoms further reinforce the anxiety in the presence of others. A 2006 study found that the area of the brain called the amygdala, part of the limbic system, is hyperactive when patients are shown threatening faces or confronted with frightening situations. They found that patients with more severe social phobia showed a correlation with the increased response in the amygdala.

Comorbidity.

SAD shows a high degree of co-occurrence with other psychiatric disorders. In fact, a population-based study found that 66% of those with SAD had one or more additional mental health disorders. SAD often occurs alongside low self-esteem and most commonly clinical depression, perhaps due to a lack of personal relationships and long periods of isolation related to social avoidance. Clinical depression is 1.49 to 3.5 times more likely to occur in those with SAD.<ref name="doi10.1001/archpsyc.64.8.903|noedit"></ref><ref name="doi10.1001/archpsyc.58.3.251|noedit"></ref> Anxiety disorders other than SAD are also very common in patients with SAD, in particular generalized anxiety disorder. Avoidant personality disorder is likewise highly correlated with SAD, with comorbidity rates ranging from 25% to 89%.  To try to reduce their anxiety and alleviate depression, people with social phobia may use alcohol or other drugs, which can lead to substance abuse. It is estimated that one-fifth of patients with social anxiety disorder also suffer from alcohol dependence. However, some research suggests SAD is unrelated to, or even protective against alcohol-related problems. Those who suffer from both alcoholism and social anxiety disorder are more likely to avoid group-based treatments and to relapse compared to people who do not have this combination.

Causes.

Research into the causes of social anxiety and social phobia is wide-ranging, encompassing multiple perspectives from neuroscience to sociology. Scientists have yet to pinpoint the exact causes. Studies suggest that genetics can play a part in combination with environmental factors. Social phobia is not caused by other mental disorders or by substance abuse. Generally, social anxiety begins at a specific point in an individual's life. This will develop over time as the person struggles to recover. Eventually, mild social awkwardness can develop into symptoms of social anxiety or phobia.

Genetics.

It has been shown that there is a two to threefold greater risk of having social phobia if a first-degree relative also has the disorder. This could be due to genetics and/or due to children acquiring social fears and avoidance through processes of observational learning or parental psychosocial education. Studies of identical twins brought up (via adoption) in different families have indicated that, if one twin developed social anxiety disorder, then the other was between 30 percent and 50 percent more likely than average to also develop the disorder. To some extent, this "heritability" may not be specific – for example, studies have found that if a parent has any kind of anxiety disorder or clinical depression, then a child is somewhat more likely to develop an anxiety disorder or social phobia. Studies suggest that parents of those with social anxiety disorder tend to be more socially isolated themselves (Bruch and Heimberg, 1994; Caster et al., 1999), and shyness in adoptive parents is significantly correlated with shyness in adopted children (Daniels and Plomin, 1985).  Growing up with overprotective and hypercritical parents has also been associated with social anxiety disorder. Adolescents who were rated as having an insecure (anxious-ambivalent) attachment with their mother as infants were twice as likely to develop anxiety disorders by late adolescence, including social phobia.  A related line of research has investigated 'behavioural inhibition' in infants – early signs of an inhibited and introspective or fearful nature. Studies have shown that around 10–15 percent of individuals show this early temperament, which appears to be partly due to genetics. Some continue to show this trait into adolescence and adulthood, and appear to be more likely to develop social anxiety disorder.

Social experiences.

A previous negative social experience can be a trigger to social phobia, perhaps particularly for individuals high in "interpersonal sensitivity". For around half of those diagnosed with social anxiety disorder, a specific traumatic or humiliating social event appears to be associated with the onset or worsening of the disorder; this kind of event appears to be particularly related to specific social phobia, for example, regarding public speaking (Stemberg "et al.", 1995). As well as direct experiences, observing or hearing about the socially negative experiences of others (e.g. a faux pas committed by someone), or verbal warnings of social problems and dangers, may also make the development of a social anxiety disorder more likely. Social anxiety disorder may be caused by the longer-term effects of not fitting in, or being bullied, rejected or ignored (Beidel and Turner, 1998). Shy adolescents or avoidant adults have emphasised unpleasant experiences with peers or childhood bullying or harassment (Gilmartin, 1987). In one study, popularity was found to be negatively correlated with social anxiety, and children who were neglected by their peers reported higher social anxiety and fear of negative evaluation than other categories of children. Socially phobic children appear less likely to receive positive reactions from peers, and anxious or inhibited children may isolate themselves.

Cultural influences.

Cultural factors that have been related to social anxiety disorder include a society's attitude towards shyness and avoidance, affecting the ability to form relationships or access employment or education, and shame. One study found that the effects of parenting are different depending on the culture: American children appear more likely to develop social anxiety disorder if their parents emphasize the importance of others' opinions and use shame as a disciplinary strategy (Leung "et al.", 1994), but this association was not found for Chinese/Chinese-American children. In China, research has indicated that shy-inhibited children are more accepted than their peers and more likely to be considered for leadership and considered competent, in contrast to the findings in Western countries. Purely demographic variables may also play a role.  Problems in developing social skills, or'social fluency', may be a cause of some social anxiety disorder, through either inability or lack of confidence to interact socially and gain positive reactions and acceptance from others. The studies have been mixed, however, with some studies not finding significant problems in social skills while others have. What does seem clear is that the socially anxious perceive their own social skills to be low. It may be that the increasing need for sophisticated social skills in forming relationships or careers, and an emphasis on assertiveness and competitiveness, is making social anxiety problems more common, at least among the'middle classes'. An interpersonal or media emphasis on 'normal' or 'attractive' personal characteristics has also been argued to fuel perfectionism and feelings of inferiority or insecurity regarding negative evaluation from others. The need for social acceptance or social standing has been elaborated in other lines of research relating to social anxiety.

Substance-induced.

While alcohol initially relieves social phobia, excessive alcohol misuse can worsen social phobia symptoms and cause panic disorder to develop or worsen during alcohol intoxication and especially during alcohol withdrawal syndrome. This effect is not unique to alcohol but can also occur with long-term use of drugs which have a similar mechanism of action to alcohol such as the benzodiazepines which are sometimes prescribed as tranquillisers. Benzodiazepines possess anti-anxiety properties and can be useful for the short-term treatment of severe anxiety. Like the anticonvulsants, they tend to be mild and well tolerated, although there is a risk of habit-forming. Benzodiazepines are usually administered orally for the treatment of anxiety; however, occasionally lorazepam or diazepam may be given intravenously for the treatment of panic attacks.  The World Council of Anxiety does not recommend benzodiazepines for the long-term treatment of anxiety due to a range of problems associated with long-term use including tolerance, psychomotor impairment, cognitive and memory impairments, physical dependence and a benzodiazepine withdrawal syndrome upon discontinuation of benzodiazepines. Despite increasing focus on the use of antidepressants and other agents for the treatment of anxiety, benzodiazepines have remained a mainstay of anxiolytic pharmacotherapy due to their robust efficacy, rapid onset of therapeutic effect, and generally favorable side effect profile. Treatment patterns for psychotropic drugs appear to have remained stable over the past decade, with benzodiazepines being the most commonly used medication for panic disorder.  Many people who are addicted to alcohol or prescribed benzodiazepines when it is explained to them they have a choice between ongoing ill mental health or quitting and recovering from their symptoms decide on quitting alcohol or their benzodiazepines. Symptoms may temporarily worsen however, during alcohol withdrawal or benzodiazepine withdrawal.

Psychological factors.

Research has indicated the role of 'core' or 'unconditional' negative beliefs (e.g. "I am inept") and 'conditional' beliefs nearer to the surface (e.g. "If I show myself, I will be rejected"). They are thought to develop based on personality and adverse experiences and to be activated when the person feels under threat.  A secondary factor is self-concealment which involves concealing the expression of one's anxiety or its underlying beliefs. One line of work has focused more specifically on the key role of self-presentational concerns. The resulting anxiety states are seen as interfering with social performance and the ability to concentrate on interaction, which in turn creates more social problems, which strengthens the negative schema. Also highlighted has been a high focus on and worry about anxiety symptoms themselves and how they might appear to others. A similar model emphasizes the development of a distorted mental representation of the self and overestimates of the likelihood and consequences of negative evaluation, and of the performance standards that others have. Such cognitive-behavioral models consider the role of negatively biased memories of the past and the processes of rumination after an event, and fearful anticipation before it.  Studies have also highlighted the role of subtle avoidance and defensive factors, and shown how attempts to avoid feared negative evaluations or use of'safety behaviors' (Clark & Wells, 1995) can make social interaction more difficult and the anxiety worse in the long run. This work has been influential in the development of Cognitive Behavioral Therapy for social anxiety disorder, which has been shown to have efficacy.

Mechanisms.

There are many studies investigating neural bases of social anxiety disorder. Although the exact neural mechanisms have not been found yet, there is evidence relating social anxiety disorder to imbalance in some neurochemicals and hyperactivity in some brain areas.

Neurotransmitters.

Sociability is closely tied to dopaminergic neurotransmission. In a 2011 study, a direct relation between social status of volunteers and binding affinity of dopamine D2/3 receptors in the striatum was found. Other research shows that the binding affinity of dopamine D2 receptors in the striatum of social anxiety sufferers is lower than in controls. Some other research shows an abnormality in dopamine transporter density in the striatum of social anxiety sufferers. However, some researchers have been unable to replicate previous findings of evidence of dopamine abnormality in social anxiety disorder. Studies have shown high prevalence of social anxiety in Parkinson's disease and schizophrenia. In a recent study, social phobia was diagnosed in 50% of Parkinson's disease patients. Other researchers have found social phobia symptoms in patients treated with dopamine antagonists like haloperidol, emphasizing the role of dopamine neurotransmission in social anxiety disorder.  Some evidence points to the possibility that social anxiety disorder involves reduced serotonin receptor binding. A recent study reports increased serotonin transporter binding in psychotropic medication-naive patients with generalized social anxiety disorder. Although there is little evidence of abnormality in serotonin neurotransmission, the limited efficacy of medications which affect serotonin levels may indicate the role of this pathway. Paroxetine, sertraline and fluvoxamine are three SSRIs that have been approved by the FDA to treat social anxiety disorder. Some researchers believe that SSRIs decrease the activity of the amygdala. There is also increasing focus on other candidate transmitters, e.g. norepinephrine and glutamate, which may be over-active in social anxiety disorder, and the inhibitory transmitter GABA, which may be under-active in the thalamus.

Brain areas.

The amygdala is part of the limbic system which is related to fear cognition and emotional learning. Individuals with social anxiety disorder have been found to have a hypersensitive amygdala; for example in relation to social threat cues (e.g. perceived negative evaluation by another person), angry or hostile faces, and while waiting to give a speech. Recent research has also indicated that another area of the brain, the anterior cingulate cortex, which was already known to be involved in the experience of physical pain, also appears to be involved in the experience of'social pain', for example perceiving group exclusion. A 2007 meta-analysis also found that individuals with social anxiety had hyperactiviation in the amygdala and insula areas which are frequently associated with fear and negative emotional processing.

Diagnosis.

ICD-10 defines social phobia as a fear of scrutiny by other people leading to avoidance of social situations. The anxiety symptoms may present as a complaint of blushing, hand tremor, nausea or urgency of micturition. Symptoms may progress to panic attacks.  Standardized rating scales such as the Social Phobia Inventory, the SPAI-B, Liebowitz Social Anxiety Scale, and the Social Interaction Anxiety Scale can be used to screen for social anxiety disorder and measure the severity of anxiety.

Differential diagnosis.

The DSM-IV criteria stated that an individual cannot receive a diagnosis of social anxiety disorder if their symptoms are better accounted for by one of the autism spectrum disorders such as autism and Asperger syndrome.  Because of its close relationship and overlapping symptoms, treating people with social phobia may help understand the underlying connections to other mental disorders. Social anxiety disorder is often linked to bipolar disorder and attention deficit hyperactivity disorder (ADHD) and some believe that they share an underlying cyclothymic-anxious-sensitive disposition. The co-occurrence of ADHD and social phobia is very high, especially when SCT symptoms are present.<ref name="DOI10.1177/1087054706286698"></ref>

Prevention.

Prevention of anxiety disorders is one focus of research. Use of CBT and related techniques may decrease the number of children with social anxiety disorder following completion of prevention programs.

Treatment.

Psychotherapies.

The first line treatment for social anxiety disorder is cognitive behavioral therapy (CBT) with medications such as selective serotonin reuptake inhibitors (SSRIs) used only in those who are not interested in therapy. Self-help based on principles of CBT is a second-line treatment.  There is some emerging evidence for the use of acceptance and commitment therapy (ACT) in the treatment of social anxiety disorder. ACT is considered an offshoot of traditional CBT and emphasizes accepting unpleasant symptoms rather than fighting against them, as well as psychological flexibility – the ability to adapt to changing situational demands, to shift one's perspective, and to balance competing desires.<ref name="doi10.1016/j.cpr.2010.03.001"></ref> ACT may be useful as a second line treatment for this disorder in situations where CBT is ineffective or refused.  Some studies have suggested social skills training (SST) can help with social anxiety. Examples of social skills focused on during SST for social anxiety disorder include: initiating conversations, establishing friendships, interacting with members of the preferred sex, constructing a speech and assertiveness skills. However, it is not clear whether specific social skills techniques and training are required, rather than just support with general social functioning and exposure to social situations.  Given the evidence that social anxiety disorder may predict subsequent development of other psychiatric disorders such as depression, early diagnosis and treatment is important. Social anxiety disorder remains under-recognized in primary care practice, with patients often presenting for treatment only after the onset of complications such as clinical depression or substance abuse disorders.

Medications.

SSRIs.

Selective serotonin reuptake inhibitors (SSRIs), a class of antidepressants, are the first choice of medication for generalized social phobia but a second line treatment. Compared to older forms of medication, there is less risk of tolerability and drug dependency associated with SSRIs.  Paroxetine and paroxetine CR, Sertraline, Escitalopram, Venlafaxine XR and Fluvoxamine CR (luvox CR) are all approved for SAD and are all effective for it especially paroxetine. All SSRIs are somewhat effective for social anxiety except fluoxetine which was equivalent to placebo in all clinical trials except one. Paroxetine was able to change personality and significantly increase extraversion.  In a 1995 double-blind, placebo-controlled trial, the SSRI paroxetine was shown to result in clinically meaningful improvement in 55% of patients with generalized social anxiety disorder, compared with 23.9% of those taking placebo. An October 2004 study yielded similar results. Patients were treated with either fluoxetine, psychotherapy, or a placebo. The first four sets saw improvement in 50.8 to 54.2 percent of the patients. Of those assigned to receive only a placebo, 31.7% achieved a rating of 1 or 2 on the Clinical Global Impression-Improvement scale. Those who sought both therapy and medication did not see a boost in improvement. In double-blind, placebo-controlled trials other SSRIs like fluvoxamine, escitalopram and sertraline showed reduction of social anxiety symptoms, including anxiety, sensitivity to rejection and hostility.  Citalopram appears to be also effective.  General side-effects are common during the first weeks while the body adjusts to the drug. Symptoms may include headaches, nausea, insomnia and changes in sexual behavior. Treatment safety during pregnancy has not been established. In late 2004 much media attention was given to a proposed link between SSRI use and suicidality [a term that encompasses suicidal ideation and attempts at suicide as well as suicide]. For this reason, [although evidential causality between SSRI use and actual suicide has not been demonstrated] the use of SSRIs in pediatric cases of depression is now recognized by the Food and Drug Administration as warranting a cautionary statement to the parents of children who may be prescribed SSRIs by a family doctor. Recent studies have shown no increase in rates of suicide. These tests, however, represent those diagnosed with depression, not necessarily with social anxiety disorder.  In addition, studies show that more socially phobic patients treated with anti-depressant medication develop hypomania than non-phobic controls. The hypomania can be seen as the medication creating a new problem.

Other drugs.

Other prescription drugs are also used, if other methods are not effective. Before the introduction of SSRIs, monoamine oxidase inhibitors (MAOIs) such as phenelzine were frequently used in the treatment of social anxiety. Evidence continues to indicate that MAOIs are effective in the treatment and management of social anxiety disorder and they are still used, but generally only as a last resort medication, owing to concerns about dietary restrictions, possible adverse drug interactions and a recommendation of multiple doses per day. A newer type of this medication, Reversible inhibitors of monoamine oxidase subtype A (RIMAs) such as the drug moclobemide, bind reversibly to the MAO-A enzyme, greatly reducing the risk of hypertensive crisis with dietary tyramine intake.  Benzodiazepines are an alternative to SSRIs. These drugs recommended usage is for short-term relief, meaning a limited time frame of over a year, of severe, disabling anxiety. Although benzodiazepines are still sometimes prescribed for long-term everyday use in some countries, there is concern over the development of drug tolerance, dependency and misuse. It has been recommended that benzodiazepines be considered only for individuals who fail to respond to other medications. Benzodiazepines augment the action of GABA, the major inhibitory neurotransmitter in the brain; effects usually begin to appear within minutes or hours. In most patients, tolerance rapidly develops to the sedative effects of benzodiazepines, but not to the anxiolytic effects. Long-term use of benzodiazepine may result in physical dependence, and abrupt discontinuation of the drug should be avoided due to high potential for withdrawal symptoms (including tremor, insomnia, and in rare cases, seizures). A gradual tapering of the dose of clonazepam (a decrease of 0.25 mg every 2 weeks), however, has been shown to be well tolerated by patients with social anxiety disorder. Benzodiazepines are not recommended as monotherapy for patients who have major depression in addition to social anxiety disorder and should be avoided in patients with a history of substance abuse.  Certain anticonvulsant drugs such as gabapentin are effective in social anxiety disorder and may be a possible treatment alternative to benzodiazepines.  Serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine have shown similar effectiveness to the SSRIs. In Japan, Milnacipran is used in the treatment of Taijin kyofusho, a Japanese variant of social anxiety disorder. The atypical antidepressants mirtazapine and bupropion have been studied for the treatment of social anxiety disorder, and rendered mixed results.  Some people with a form of social phobia called performance phobia have been helped by beta-blockers, which are more commonly used to control high blood pressure. Taken in low doses, they control the physical manifestation of anxiety and can be taken before a public performance.  A novel treatment approach has recently been developed as a result of translational research. It has been shown that a combination of acute dosing of d-cycloserine (DCS) with exposure therapy facilitates the effects of exposure therapy of social phobia. DCS is an old antibiotic medication used for treating tuberculosis and does not have any anxiolytic properties per se. However, it acts as an agonist at the glutamatergic N-methyl-D-aspartate (NMDA) receptor site, which is important for learning and memory.  Kava-kava has also attracted attention as a possible treatment, although safety concerns exist.

Epidemiology.

Social anxiety disorder is known to appear at an early age in most cases. Fifty percent of those who develop this disorder have developed it by the age of 11, and 80% have developed it by age 20. This early age of onset may lead to people with social anxiety disorder being particularly vulnerable to depressive illnesses, drug abuse and other psychological conflicts.  When prevalence estimates were based on the examination of psychiatric clinic samples, social anxiety disorder was thought to be a relatively rare disorder. The opposite was found to be true; social anxiety was common, but many were afraid to seek psychiatric help, leading to an underrecognition of the problem.  The National Comorbidity Survey of over 8,000 American correspondents in 1994 revealed 12-month and lifetime prevalence rates of 7.9 percent and 13.3 percent, respectively; this makes it the third most prevalent psychiatric disorder after depression and alcohol dependence, and the most common of the anxiety disorders. According to US epidemiological data from the National Institute of Mental Health, social phobia affects 15 million adult Americans in any given year. Estimates vary within 2 percent and 7 percent of the U.S. adult population.  The mean onset of social phobia is 10 to 13 years. Onset after age 25 is rare and is typically preceded by panic disorder or major depression. Social anxiety disorder occurs more often in females than males. The prevalence of social phobia appears to be increasing among white, married, and well-educated individuals. As a group, those with generalized social phobia are less likely to graduate from high school and are more likely to rely on government financial assistance or have poverty-level salaries. Surveys carried out in 2002 show the youth of England, Scotland, and Wales have a prevalence rate of 0.4 percent, 1.8 percent, and 0.6 percent, respectively. In Canada, the prevalence of self-reported social anxiety for Nova Scotians older than 14 years was 4.2 percent in June 2004 with women (4.6 percent) reporting more than men (3.8 percent). In Australia, social phobia is the 8th and 5th leading disease or illness for males and females between 15–24 years of age as of 2003. Because of the difficulty in separating social phobia from poor social skills or shyness, some studies have a large range of prevalence. The table also shows higher prevalence in Sweden.

History.

Literary descriptions of shyness can be traced back to the days of Hippocrates around 400 B.C. Hippocrates described someone who "through bashfulness, suspicion, and timorousness, will not be seen abroad; loves darkness as life and cannot endure the light or to sit in lightsome places; his hat still in his eyes, he will neither see, nor be seen by his good will. He dare not come in company for fear he should be misused, disgraced, overshoot himself in gesture or speeches, or be sick; he thinks every man observes him."  The first mention of the psychiatric term "social phobia" ("phobie des situations sociales") was made in the early 1900s. Psychologists used the term "social neurosis" to describe extremely shy patients in the 1930s. After extensive work by Joseph Wolpe on systematic desensitization, research on phobias and their treatment grew. The idea that social phobia was a separate entity from other phobias came from the British psychiatrist Isaac Marks in the 1960s. This was accepted by the American Psychiatric Association and was first officially included in the third edition of the Diagnostic and Statistical Manual of Mental Disorders. The definition of the phobia was revised in 1989 to allow comorbidity with avoidant personality disorder and introduced generalized social phobia. Social phobia had been largely ignored prior to 1985.  After a call to action by psychiatrist Michael Liebowitz and clinical psychologist Richard Heimberg, there was an increase in attention to and research on the disorder. The DSM-IV gave social phobia the alternative name "social anxiety disorder". Research on the psychology and sociology of everyday social anxiety continued. Cognitive Behavioural models and therapies were developed for social anxiety disorder. In the 1990s, paroxetine became the first prescription drug in the U.S. approved to treat social anxiety disorder, with others following.

Terminology.

It has also been referred to as anthropophobia and anthrophobia, meaning "fear of humans", from, "ánthropos", "human" and, "phóbos", "fear". Other names have included interpersonal relation phobia. A specific Japanese cultural form is known as taijin kyofusho.

Social anxiety disorder (SAD), also known as social phobia, is an anxiety disorder characterized by sentiments of fear and anxiety in social situations, causing considerable distress and impaired ability to function in at least some aspects of daily life. These fears can be triggered by perceived or actual scrutiny from others. Individuals with social anxiety disorder fear negative evaluation from other people.

社交恐惧症又名社会焦虑症、人群恐惧症,是一种对任何社交或公开场合感到强烈恐惧或忧虑的精神疾病。患者对于在陌生人面前或可能被别人仔细观察的社交或表演场合,有一种显著且持久的恐惧,害怕自己的行为或紧张的表现会引起羞辱或难堪。有些患者对参加聚会、打电话、到商店购物或询问权威人士都感到困难。在心理学上被诊断为社交焦虑失协症(social anxiety disorder, SAD),是焦虑症的一种。此症最早被发现于1985年,当时被认为是忽略性焦虑失协症(neglect anxiety disorder),经过14年才渐渐被重视。


History.

M73 was discovered by Charles Messier on October 4, 1780, who originally described the object as a cluster of four stars with some nebulosity. Subsequent observations by John Herschel, however, failed to reveal any nebulosity. Moreover, Herschel noted that the designation of M73 as a cluster was questionable. Nonetheless, Herschel included M73 in his General Catalogue of clusters, nebulae, and galaxies, and John Dreyer included M73 when he compiled the New General Catalogue.

Scientific research: asterism or open cluster?

M73 was once treated as a potential sparsely populated open cluster, which consists of stars that are physically associated in space as well as on the sky. The question of whether the stars were an asterism or an open cluster generated a small, interesting debate.  In 2000, L. P. Bassino, S. Waldhausen, and R. E. Martinez published an analysis of the colors and luminosities of the stars in and around M73. They concluded that the four bright central stars and some other nearby stars followed the color-luminosity relation that is also followed by stars in open clusters (as seen in a Hertzsprung-Russell diagram). Their conclusion was that M73 was an old open cluster that was 9 arcmin wide. G. Carraro, however, published results in 2000 based on a similar analysis and concluded that the stars did not follow any color-luminosity relation. Carraro's conclusion was that M73 was an asterism. Adding to the controversy, E. Bica and collaborators concluded that the chance alignment of the four bright stars seen in the center of M73 as well as one other nearby star was highly unlikely, so M73 was probably a sparse open cluster. The controversy was solved in 2002, when M. Odenkirchen and C. Soubiran published an analysis of the high resolution spectra of the six brightest stars within 6 arcmin of the central position of M73. Odenkirchen and Soubiran demonstrated that the distances from the Earth to the six stars were very different from each other, and the stars were moving in different directions. Therefore, they concluded that the stars were only an asterism.  Although M73 was determined to be only a chance alignment of stars, further analysis of asterisms is still important for the identification of sparsely populated open clusters. Such clusters can be important for demonstrating how open clusters are ripped apart by the gravitational forces in the Milky Way.

Location.

The asterism's location in the sky is shown in the following map of the constellation Aquarius:

Messier 73 (M73, also known as NGC 6994) is an asterism of four stars in the constellation of Aquarius. An asterism is composed of physically unconnected stars that appear close to each other in the sky as seen from Earth.

梅西尔73(也称为M73或NGC 6994)是位于宝瓶座内,以四颗恒星为主体的星群。所谓星群,只是从地球上看天空中聚在一起,但彼此完全没有关联的恒星。M73是天空中最著名,并且曾被仔细的研究过的星群之一。