chunks
stringlengths 1
1.02k
|
|---|
mixture of cryolite Na3AlF6 with calcium fluoride is electrolyzed to produce metallic aluminium. The liquid aluminium metal sinks to the bottom of the solution and is tapped off, and usually cast into large blocks called aluminium billets for further processing.
Anodes of the electrolysis cell are made of carbonthe most resistant material against fluoride corrosionand either bake at the process or are prebaked. The former, also called Sderberg anodes, are less powerefficient and fumes released during baking are costly to collect, which is why they are being replaced by prebaked anodes even though they save the power, energy, and labor to prebake the cathodes. Carbon for anodes should be preferably pure so that neither aluminium nor the electrolyte is contaminated with ash. Despite carbon's resistivity against corrosion, it is still consumed at a rate of 0.40.5 kg per each kilogram of produced aluminium. Cathodes are made of anthracite; high purity for them is not required because impurities leach only very
|
slowly. The cathode is consumed at a rate of 0.020.04 kg per each kilogram of produced aluminium. A cell is usually terminated after 26 years following a failure of the cathode.
The HallHeroult process produces aluminium with a purity of above 99. Further purification can be done by the Hoopes process. This process involves the electrolysis of molten aluminium with a sodium, barium, and aluminium fluoride electrolyte. The resulting aluminium has a purity of 99.99.
Electric power represents about 20 to 40 of the cost of producing aluminium, depending on the location of the smelter. Aluminium production consumes roughly 5 of electricity generated in the United States. Because of this, alternatives to the HallHroult process have been researched, but none has turned out to be economically feasible.
Recycling
Recovery of the metal through recycling has become an important task of the aluminium industry. Recycling was a lowprofile activity until the late 1960s, when the growing use of aluminium beverage cans b
|
rought it to public awareness. Recycling involves melting the scrap, a process that requires only 5 of the energy used to produce aluminium from ore, though a significant part up to 15 of the input material is lost as dross ashlike oxide. An aluminium stack melter produces significantly less dross, with values reported below 1.
White dross from primary aluminium production and from secondary recycling operations still contains useful quantities of aluminium that can be extracted industrially. The process produces aluminium billets, together with a highly complex waste material. This waste is difficult to manage. It reacts with water, releasing a mixture of gases including, among others, hydrogen, acetylene, and ammonia, which spontaneously ignites on contact with air; contact with damp air results in the release of copious quantities of ammonia gas. Despite these difficulties, the waste is used as a filler in asphalt and concrete.
Applications
Metal
The global production of aluminium in 2016 was 58.8 mil
|
lion metric tons. It exceeded that of any other metal except iron 1,231 million metric tons.
Aluminium is almost always alloyed, which markedly improves its mechanical properties, especially when tempered. For example, the common aluminium foils and beverage cans are alloys of 92 to 99 aluminium. The main alloying agents are copper, zinc, magnesium, manganese, and silicon e.g., duralumin with the levels of other metals in a few percent by weight. Aluminium, both wrought and cast, has been alloyed with manganese, silicon, magnesium, copper and zinc among others. For example, the Kynal family of alloys was developed by the British chemical manufacturer Imperial Chemical Industries.
The major uses for aluminium metal are in
Transportation automobiles, aircraft, trucks, railway cars, marine vessels, bicycles, spacecraft, etc.. Aluminium is used because of its low density;
Packaging cans, foil, frame, etc.. Aluminium is used because it is nontoxic see below, nonadsorptive, and splinterproof;
Building and cons
|
truction windows, doors, siding, building wire, sheathing, roofing, etc.. Since steel is cheaper, aluminium is used when lightness, corrosion resistance, or engineering features are important;
Electricityrelated uses conductor alloys, motors, and generators, transformers, capacitors, etc.. Aluminium is used because it is relatively cheap, highly conductive, has adequate mechanical strength and low density, and resists corrosion;
A wide range of household items, from cooking utensils to furniture. Low density, good appearance, ease of fabrication, and durability are the key factors of aluminium usage;
Machinery and equipment processing equipment, pipes, tools. Aluminium is used because of its corrosion resistance, nonpyrophoricity, and mechanical strength.
Portable computer cases. Currently rarely used without alloying, but aluminium can be recycled and clean aluminium has residual market value for example, the used beverage can UBC material was used to encase the electronic components of MacBook Air lapto
|
p, Pixel 5 smartphone or Summit Lite smartwatch.
Compounds
The great majority about 90 of aluminium oxide is converted to metallic aluminium. Being a very hard material Mohs hardness 9, alumina is widely used as an abrasive; being extraordinarily chemically inert, it is useful in highly reactive environments such as high pressure sodium lamps. Aluminium oxide is commonly used as a catalyst for industrial processes; e.g. the Claus process to convert hydrogen sulfide to sulfur in refineries and to alkylate amines. Many industrial catalysts are supported by alumina, meaning that the expensive catalyst material is dispersed over a surface of the inert alumina. Another principal use is as a drying agent or absorbent.
Several sulfates of aluminium have industrial and commercial application. Aluminium sulfate in its hydrate form is produced on the annual scale of several millions of metric tons. About twothirds is consumed in water treatment. The next major application is in the manufacture of paper. It is also us
|
ed as a mordant in dyeing, in pickling seeds, deodorizing of mineral oils, in leather tanning, and in production of other aluminium compounds. Two kinds of alum, ammonium alum and potassium alum, were formerly used as mordants and in leather tanning, but their use has significantly declined following availability of highpurity aluminium sulfate. Anhydrous aluminium chloride is used as a catalyst in chemical and petrochemical industries, the dyeing industry, and in synthesis of various inorganic and organic compounds. Aluminium hydroxychlorides are used in purifying water, in the paper industry, and as antiperspirants. Sodium aluminate is used in treating water and as an accelerator of solidification of cement.
Many aluminium compounds have niche applications, for example
Aluminium acetate in solution is used as an astringent.
Aluminium phosphate is used in the manufacture of glass, ceramic, pulp and paper products, cosmetics, paints, varnishes, and in dental cement.
Aluminium hydroxide is used as an antac
|
id, and mordant; it is used also in water purification, the manufacture of glass and ceramics, and in the waterproofing of fabrics.
Lithium aluminium hydride is a powerful reducing agent used in organic chemistry.
Organoaluminiums are used as Lewis acids and cocatalysts.
Methylaluminoxane is a cocatalyst for ZieglerNatta olefin polymerization to produce vinyl polymers such as polyethene.
Aqueous aluminium ions such as aqueous aluminium sulfate are used to treat against fish parasites such as Gyrodactylus salaris.
In many vaccines, certain aluminium salts serve as an immune adjuvant immune response booster to allow the protein in the vaccine to achieve sufficient potency as an immune stimulant.
Biology
Despite its widespread occurrence in the Earth's crust, aluminium has no known function in biology. At pH 69 relevant for most natural waters, aluminium precipitates out of water as the hydroxide and is hence not available; most elements behaving this way have no biological role or are toxic. Aluminium s
|
alts are nontoxic. Aluminium sulfate has an LD50 of 6207 mgkg oral, mouse, which corresponds to 435 grams for an person, though lethality and neurotoxicity differ in their implications. Andrsi et al. discovered "significantly higher Aluminum" content in some brain regions when necroscopies of subjects with Alzheimer disease were compared to subjects without. Aluminium chelates with glyphosate.
Toxicity
Aluminium is classified as a noncarcinogen by the United States Department of Health and Human Services. A review published in 1988 said that there was little evidence that normal exposure to aluminium presents a risk to healthy adult, and a 2014 multielement toxicology review was unable to find deleterious effects of aluminium consumed in amounts not greater than 40 mgday per kg of body mass. Most aluminium consumed will leave the body in feces; most of the small part of it that enters the bloodstream, will be excreted via urine; nevertheless some aluminium does pass the bloodbrain barrier and is lodged pr
|
eferentially in the brains of Alzheimer's patients. Evidence published in 1989 indicates that, for Alzheimer's patients, aluminium may act by electrostatically crosslinking proteins, thus downregulating genes in the superior temporal gyrus.
Effects
Aluminium, although rarely, can cause vitamin Dresistant osteomalacia, erythropoietinresistant microcytic anemia, and central nervous system alterations. People with kidney insufficiency are especially at a risk. Chronic ingestion of hydrated aluminium silicates for excess gastric acidity control may result in aluminium binding to intestinal contents and increased elimination of other metals, such as iron or zinc; sufficiently high doses 50 gday can cause anemia.
During the 1988 Camelford water pollution incident people in Camelford had their drinking water contaminated with aluminium sulfate for several weeks. A final report into the incident in 2013 concluded it was unlikely that this had caused longterm health problems.
Aluminium has been suspected of being
|
a possible cause of Alzheimer's disease, but research into this for over 40 years has found, , no good evidence of causal effect.
Aluminium increases estrogenrelated gene expression in human breast cancer cells cultured in the laboratory. In very high doses, aluminium is associated with altered function of the bloodbrain barrier. A small percentage of people have contact allergies to aluminium and experience itchy red rashes, headache, muscle pain, joint pain, poor memory, insomnia, depression, asthma, irritable bowel syndrome, or other symptoms upon contact with products containing aluminium.
Exposure to powdered aluminium or aluminium welding fumes can cause pulmonary fibrosis. Fine aluminium powder can ignite or explode, posing another workplace hazard.
Exposure routes
Food is the main source of aluminium. Drinking water contains more aluminium than solid food; however, aluminium in food may be absorbed more than aluminium from water. Major sources of human oral exposure to aluminium include food due
|
to its use in food additives, food and beverage packaging, and cooking utensils, drinking water due to its use in municipal water treatment, and aluminiumcontaining medications particularly antacidantiulcer and buffered aspirin formulations. Dietary exposure in Europeans averages to 0.21.5 mgkgweek but can be as high as 2.3 mgkgweek. Higher exposure levels of aluminium are mostly limited to miners, aluminium production workers, and dialysis patients.
Consumption of antacids, antiperspirants, vaccines, and cosmetics provide possible routes of exposure. Consumption of acidic foods or liquids with aluminium enhances aluminium absorption, and maltol has been shown to increase the accumulation of aluminium in nerve and bone tissues.
Treatment
In case of suspected sudden intake of a large amount of aluminium, the only treatment is deferoxamine mesylate which may be given to help eliminate aluminium from the body by chelation. However, this should be applied with caution as this reduces not only aluminium body
|
levels, but also those of other metals such as copper or iron.
Environmental effects
High levels of aluminium occur near mining sites; small amounts of aluminium are released to the environment at the coalfired power plants or incinerators. Aluminium in the air is washed out by the rain or normally settles down but small particles of aluminium remain in the air for a long time.
Acidic precipitation is the main natural factor to mobilize aluminium from natural sources and the main reason for the environmental effects of aluminium; however, the main factor of presence of aluminium in salt and freshwater are the industrial processes that also release aluminium into air.
In water, aluminium acts as a toxi agent on gillbreathing animals such as fish when the water is acidic, in which aluminium may precipitate on gills, which causes loss of plasma and hemolymph ions leading to osmoregulatory failure. Organic complexes of aluminium may be easily absorbed and interfere with metabolism in mammals and birds, even th
|
ough this rarely happens in practice.
Aluminium is primary among the factors that reduce plant growth on acidic soils. Although it is generally harmless to plant growth in pHneutral soils, in acid soils the concentration of toxic Al3 cations increases and disturbs root growth and function. Wheat has developed a tolerance to aluminium, releasing organic compounds that bind to harmful aluminium cations. Sorghum is believed to have the same tolerance mechanism.
Aluminium production possesses its own challenges to the environment on each step of the production process. The major challenge is the greenhouse gas emissions. These gases result from electrical consumption of the smelters and the byproducts of processing. The most potent of these gases are perfluorocarbons from the smelting process. Released sulfur dioxide is one of the primary precursors of acid rain.
A Spanish scientific report from 2001 claimed that the fungus Geotrichum candidum consumes the aluminium in compact discs. Other reports all refer ba
|
ck to that report and there is no supporting original research. Better documented, the bacterium Pseudomonas aeruginosa and the fungus Cladosporium resinae are commonly detected in aircraft fuel tanks that use kerosenebased fuels not avgas, and laboratory cultures can degrade aluminium. However, these life forms do not directly attack or consume the aluminium; rather, the metal is corroded by microbe waste products.
See also
Aluminium granules
Aluminium joining
Aluminiumair battery
Panel edge staining
Quantum clock
Notes
References
Bibliography
Further reading
Mimi Sheller, Aluminum Dream The Making of Light Modernity. Cambridge, Mass. Massachusetts Institute of Technology Press, 2014.
External links
Aluminium at The Periodic Table of Videos University of Nottingham
Toxic Substances Portal Aluminum from the Agency for Toxic Substances and Disease Registry, United States Department of Health and Human Services
CDC NIOSH Pocket Guide to Chemical Hazards Aluminum
World production of primar
|
y aluminium, by country
Price history of aluminum, according to the IMF
History of Aluminium from the website of the International Aluminium Institute
Emedicine Aluminium
Aluminium
Electrical conductors
Pyrotechnic fuels
Airship technology
Chemical elements
Posttransition metals
Reducing agents
Enumber additives
Native element minerals
Chemical elements with facecentered cubic structure
|
Advanced Chemistry is a German hip hop group from Heidelberg, a scenic city in BadenWrttemberg, South Germany. Advanced Chemistry was founded in 1987 by Toni L, Linguist, GeeOne, DJ Mike MD Mike Dippon and MC Torch. Each member of the group holds German citizenship, and Toni L, Linguist, and Torch are of Italian, Ghanaian, and Haitian backgrounds, respectively.
Influenced by North American socially conscious rap and the Native tongues movement, Advanced Chemistry is regarded as one of the main pioneers in German hip hop. They were one of the first groups to rap in German although their name is in English. Furthermore, their songs tackled controversial social and political issues, distinguishing them from early German hip hop group "Die Fantastischen Vier" The Fantastic Four, which had a more lighthearted, playful, party image.
Career
Advanced Chemistry frequently rapped about their lives and experiences as children of immigrants, exposing the marginalization experienced by most ethnic minorities in Germany
|
, and the feelings of frustration and resentment that being denied a German identity can cause. The song "Fremd im eigenen Land" Foreign in your own nation was released by Advanced Chemistry in November 1992. The single became a staple in the German hip hop scene. It made a strong statement about the status of immigrants throughout Germany, as the group was composed of multinational and multiracial members. The video shows several members brandishing their German passports as a demonstration of their German citizenship to skeptical and unaccepting 'ethnic' Germans.
This idea of national identity is important, as many rap artists in Germany have been of foreign origin. These socalled Gastarbeiter guest workers children saw breakdance, graffiti, rap music, and hip hop culture as a means of expressing themselves. Since the release of "Fremd im eigenen Land", many other Germanlanguage rappers have also tried to confront antiimmigrant ideas and develop themes of citizenship. However, though many ethnic minority y
|
outh in Germany find these German identity themes appealing, others view the desire of immigrants to be seen as German negatively, and they have actively sought to revive and recreate concepts of identity in connection to traditional ethnic origins.
Advanced Chemistry helped to found the German chapter of the Zulu nation.
The rivalry between Advanced Chemistry and Die Fantastischen Vier has served to highlight a dichotomy in the routes that hip hop has taken in becoming a part of the German soundscape. While Die Fantastischen Vier may be said to view hip hop primarily as an aesthetic art form, Advanced Chemistry understand hip hop as being inextricably linked to the social and political circumstances under which it is created. For Advanced Chemistry, hip hop is a vehicle of general human emancipation,. In their undertaking of social and political issues, the band introduced the term "AfroGerman" into the context of German hip hop, and the theme of race is highlighted in much of their music.
With the r
|
elease of the single Fremd im eigenen Land, Advanced Chemistry separated itself from the rest of the rap being produced in Germany. This single was the first of its kind to go beyond simply imitating US rap and addressed the current issues of the time. Fremd im eigenen Land which translates to foreign in my own country dealt with the widespread racism that nonwhite German citizens faced. This change from simple imitation to political commentary was the start of German identification with rap. The sound of Fremd im eigenen Land was influenced by the 'wall of noise' created by Public Enemy's producers, The Bomb Squad.
After the reunification of Germany, an abundance of antiimmigrant sentiment emerged, as well as attacks on the homes of refugees in the early 1990s. Advanced Chemistry came to prominence in the wake of these actions because of their promulticultural society stance in their music. Advanced Chemistry's attitudes revolve around their attempts to create a distinct "Germanness" in hip hop, as oppo
|
sed to imitating American hip hop as other groups had done. Torch has said, "What the Americans do is exotic for us because we don't live like they do. What they do seems to be more interesting and newer. But not for me. For me it's more exciting to experience my fellow Germans in new contexts...For me, it's interesting to see what the kids try to do that's different from what I know." Advanced Chemistry were the first to use the term "AfroGerman" in a hip hop context. This was part of the proimmigrant political message they sent via their music.
While Advanced Chemistry's use of the German language in their rap allows them to make claims to authenticity and true German heritage, bolstering proimmigration sentiment, their style can also be problematic for immigrant notions of any real ethnic roots. Indeed, part of the Turkish ethnic minority of Frankfurt views Advanced Chemistry's appeal to the German image as a "symbolic betrayal of the right of ethnic minorities to 'roots' or to any expression of cult
|
ural heritage." In this sense, their rap represents a complex social discourse internal to the German soundscape in which they attempt to negotiate immigrant assimilation into a xenophobic German culture with the maintenance of their own separate cultural traditions. It is quite possibly the feelings of alienation from the pureblooded German demographic that drive Advanced Chemistry to attack nationalistic ideologies by asserting their "Germanness" as a group composed primarily of ethnic others. The response to this pseudoGerman authenticity can be seen in what Andy Bennett refers to as "alternative forms of local hip hop culture which actively seek to rediscover and, in many cases, reconstruct notions of identity tied to cultural roots." These alternative local hip hop cultures include oriental hip hop, the members of which cling to their Turkish heritage and are confused by Advanced Chemistry's elicitation of a German identity politics to which they technically do not belong. This cultural binary illustrate
|
s that rap has taken different routes in Germany and that, even among an already isolated immigrant population, there is still disunity and, especially, disagreement on the relative importance of assimilation versus cultural defiance. According to German hip hop enthusiast 9home, Advanced Chemistry is part of a "hiphop movement which took a clear stance for the minorities and against the marginalization of immigrants who...might be German on paper, but not in real life," which speaks to the group's hope of actually being recognized as German citizens and not foreigners, despite their various other ethnic and cultural ties.
Influences
Advanced Chemistry's work was rooted in German history and the country's specific political realities. However, they also drew inspiration from AfricanAmerican hiphop acts like A Tribe Called Quest and Public Enemy, who had helped bring a soulful sound and political consciousness to American hiphop. One member, Torch, later explicitly listed his references on his solo song "Als
|
When I Was in School" "My favorite subject, which was quickly discovered poetry in load Poets, awakens the intellect or policy at Chuck D I'll never forget the lyrics by Public Enemy." Torch goes on to list other American rappers like Biz Markie, Big Daddy Kane and Dr. Dre as influences.
Discography
1992 "Fremd im eigenen Land" 12"MCD, MZEE
1993 "Welcher Pfad fhrt zur Geschichte" 12"MCD, MZEE
1994 "Operation 3" 12"MCD
1994 "Dir fehlt der Funk!" 12"MCD
1995 Advanced Chemistry 2xLPCD
External links
Official Website of MC Torch
Website of Toni L
Official Website of Linguist
Official Website DJ Mike MD Mike Dippon
Website of 360 Records
Bibliography
ElTayeb, Fatima If You Cannot Pronounce My Name, You Can Just Call Me
Pride. AfroGerman Activism, Gender, and Hip Hop, Gender History1532003459485.
Felbert, Oliver von. Die Unbestechlichen. Spex March 1993 5053.
Weheliye, Alexander G. PhonographiesGrooves in Sonic AfroModernity, Duke University Press, 2005.
References
German hip hop groups
|
The Anglican Communion is the third largest Christian communion after the Roman Catholic and Eastern Orthodox churches. Founded in 1867 in London, the communion has more than 85 million members within the Church of England and other autocephalous national and regional churches in full communion. The traditional origins of Anglican doctrine are summarised in the Thirtynine Articles 1571. The Archbishop of Canterbury currently Justin Welby in England acts as a focus of unity, recognised as primus inter pares "first among equals", but does not exercise authority in Anglican provinces outside of the Church of England. Most, but not all, member churches of the communion are the historic national or regional Anglican churches.
The Anglican Communion was officially and formally organised and recognised as such at the Lambeth Conference in 1867 in London under the leadership of Charles Longley, Archbishop of Canterbury. The churches of the Anglican Communion consider themselves to be part of the one, holy, catholic
|
and apostolic church, and to be both catholic and reformed. As in the Church of England itself, the Anglican Communion includes the broad spectrum of beliefs and liturgical practises found in the Evangelical, Central and AngloCatholic traditions of Anglicanism. Each national or regional church is fully independent, retaining its own legislative process and episcopal polity under the leadership of local primates. For some adherents, Anglicanism represents a nonpapal Catholicism, for others a form of Protestantism though without a guiding figure such as Luther, Knox, Calvin, Zwingli or Wesley, or for yet others a combination of the two.
Most of its members live in the Anglosphere of former British territories. Full participation in the sacramental life of each church is available to all communicant members. Because of their historical link to England ecclesia anglicana means "English church", some of the member churches are known as "Anglican", such as the Anglican Church of Canada. Others, for example the Chu
|
rch of Ireland and the Scottish and American Episcopal churches, have official names that do not include "Anglican". Additionally, some churches which use the name "Anglican" are not part of the communion.
Ecclesiology, polity and ethos
The Anglican Communion has no official legal existence nor any governing structure which might exercise authority over the member churches. There is an Anglican Communion Office in London, under the aegis of the Archbishop of Canterbury, but it only serves in a supporting and organisational role. The communion is held together by a shared history, expressed in its ecclesiology, polity and ethos, and also by participation in international consultative bodies.
Three elements have been important in holding the communion together first, the shared ecclesial structure of the component churches, manifested in an episcopal polity maintained through the apostolic succession of bishops and synodical government; second, the principle of belief expressed in worship, investing importan
|
ce in approved prayer books and their rubrics; and third, the historical documents and the writings of early Anglican divines that have influenced the ethos of the communion.
Originally, the Church of England was selfcontained and relied for its unity and identity on its own history, its traditional legal and episcopal structure, and its status as an established church of the state. As such, Anglicanism was from the outset a movement with an explicitly episcopal polity, a characteristic that has been vital in maintaining the unity of the communion by conveying the episcopate's role in manifesting visible catholicity and ecumenism.
Early in its development following the English Reformation, Anglicanism developed a vernacular prayer book, called the Book of Common Prayer. Unlike other traditions, Anglicanism has never been governed by a magisterium nor by appeal to one founding theologian, nor by an extracredal summary of doctrine such as the Westminster Confession of the Presbyterian churches. Instead, Angli
|
cans have typically appealed to the Book of Common Prayer 1662 and its offshoots as a guide to Anglican theology and practise. This has had the effect of inculcating in Anglican identity and confession the principle of lex orandi, lex credendi "the law of praying is the law of believing".
Protracted conflict through the 17th century, with radical Protestants on the one hand and Roman Catholics who recognised the primacy of the Pope on the other, resulted in an association of churches that was both deliberately vague about doctrinal principles, yet bold in developing parameters of acceptable deviation. These parameters were most clearly articulated in the various rubrics of the successive prayer books, as well as the ThirtyNine Articles of Religion 1563. These articles have historically shaped and continue to direct the ethos of the communion, an ethos reinforced by its interpretation and expansion by such influential early theologians such as Richard Hooker, Lancelot Andrewes and John Cosin.
With the expans
|
ion of the British Empire the growth of Anglicanism outside Great Britain and Ireland, the communion sought to establish new vehicles of unity. The first major expressions of this were the Lambeth Conferences of the communion's bishops, first convened in 1867 by Charles Longley, the Archbishop of Canterbury. From the beginning, these were not intended to displace the autonomy of the emerging provinces of the communion, but to "discuss matters of practical interest, and pronounce what we deem expedient in resolutions which may serve as safe guides to future action".
Chicago Lambeth Quadrilateral
One of the enduringly influential early resolutions of the conference was the socalled ChicagoLambeth Quadrilateral of 1888. Its intent was to provide the basis for discussions of reunion with the Roman Catholic and Orthodox churches, but it had the ancillary effect of establishing parameters of Anglican identity. It establishes four principles with these words
Instruments of communion
As mentioned above, the Anglic
|
an Communion has no international juridical organisation. The Archbishop of Canterbury's role is strictly symbolic and unifying and the communion's three international bodies are consultative and collaborative, their resolutions having no legal effect on the autonomous provinces of the communion. Taken together, however, the four do function as "instruments of communion", since all churches of the communion participate in them. In order of antiquity, they are
The Archbishop of Canterbury functions as the spiritual head of the communion. The archbishop is the focus of unity, since no church claims membership in the Communion without being in communion with him. The present archbishop is Justin Welby.
The Lambeth Conference first held in 1867 is the oldest international consultation. It is a forum for bishops of the communion to reinforce unity and collegiality through manifesting the episcopate, to discuss matters of mutual concern, and to pass resolutions intended to act as guideposts. It is held roughly e
|
very 10 years and invitation is by the Archbishop of Canterbury.
The Anglican Consultative Council first met in 1971 was created by a 1968 Lambeth Conference resolution, and meets usually at threeyearly intervals. The council consists of representative bishops, other clergy and laity chosen by the 38 provinces. The body has a permanent secretariat, the Anglican Communion Office, of which the Archbishop of Canterbury is president.
The Primates' Meeting first met in 1979 is the most recent manifestation of international consultation and deliberation, having been first convened by Archbishop Donald Coggan as a forum for "leisurely thought, prayer and deep consultation".
Since there is no binding authority in the Anglican Communion, these international bodies are a vehicle for consultation and persuasion. In recent times, persuasion has tipped over into debates over conformity in certain areas of doctrine, discipline, worship and ethics. The most notable example has been the objection of many provinces of the
|
communion particularly in Africa and Asia to the changing acceptance of LGBTQ individuals in the North American churches e.g., by blessing samesex unions and ordaining and consecrating samesex relationships and to the process by which changes were undertaken. See Anglican realignment
Those who objected condemned these actions as unscriptural, unilateral, and without the agreement of the communion prior to these steps being taken. In response, the American Episcopal Church and the Anglican Church of Canada answered that the actions had been undertaken after lengthy scriptural and theological reflection, legally in accordance with their own canons and constitutions and after extensive consultation with the provinces of the communion.
The Primates' Meeting voted to request the two churches to withdraw their delegates from the 2005 meeting of the Anglican Consultative Council. Canada and the United States decided to attend the meeting but without exercising their right to vote. They have not been expelled or su
|
spended, since there is no mechanism in this voluntary association to suspend or expel an independent province of the communion. Since membership is based on a province's communion with Canterbury, expulsion would require the Archbishop of Canterbury's refusal to be in communion with the affected jurisdictions. In line with the suggestion of the Windsor Report, Rowan Williams the then Archbishop of Canterbury established a working group to examine the feasibility of an Anglican covenant which would articulate the conditions for communion in some fashion.
Organisation
Provinces
The Anglican communion consists of fortyone autonomous provinces each with its own primate and governing structure. These provinces may take the form of national churches such as in Canada, Uganda, or Japan or a collection of nations such as the West Indies, Central Africa, or Southeast Asia.
Extraprovincial churches
In addition to the fortyone provinces, there are five extraprovincial churches under the metropolitical authority of
|
the Archbishop of Canterbury.
Former provinces
New provinces in formation
At its Autumn 2020 meeting the provincial standing committee of the Church of Southern Africa approved a plan to form the dioceses in Mozambique and Angola into a separate autonomous province of the Anglican Communion, to be named the Anglican Church of Mozambique and Angola IAMA. The plans were also outlined to the Mozambique and Angola Anglican Association MANNA at its September 2020 annual general meeting. The new province is Portuguesespeaking, and consists of twelve dioceses four in Angola, and eight in Mozambique. The twelve proposed new dioceses have been defined and named, and each has a "Task Force Committee" working towards its establishment as a diocese. The plan received the consent of the bishops and diocesan synods of all four existing dioceses in the two nations, and was submitted to the Anglican Consultative Council.
In September 2020 the Archbishop of Canterbury announced that he had asked the bishops of the Church
|
of Ceylon to begin planning for the formation of an autonomous province of Ceylon, so as to end his current position as Metropolitan of the two dioceses in that country.
Churches in full communion
In addition to other member churches, the churches of the Anglican Communion are in full communion with the Old Catholic churches of the Union of Utrecht and the Scandinavian Lutheran churches of the Porvoo Communion in Europe, the Indiabased Malankara Mar Thoma Syrian and Malabar Independent Syrian churches and the Philippine Independent Church, also known as the Aglipayan Church.
History
The Anglican Communion traces much of its growth to the older mission organisations of the Church of England such as the Society for Promoting Christian Knowledge founded 1698, the Society for the Propagation of the Gospel in Foreign Parts founded 1701 and the Church Missionary Society founded 1799. The Church of England which until the 20th century included the Church in Wales initially separated from the Roman Catholic Chu
|
rch in 1534 in the reign of Henry VIII, reunited in 1555 under Mary I and then separated again in 1570 under Elizabeth I the Roman Catholic Church excommunicated Elizabeth I in 1570 in response to the Act of Supremacy 1559.
The Church of England has always thought of itself not as a new foundation but rather as a reformed continuation of the ancient "English Church" Ecclesia Anglicana and a reassertion of that church's rights. As such it was a distinctly national phenomenon. The Church of Scotland was formed as a separate church from the Roman Catholic Church as a result of the Scottish Reformation in 1560 and the later formation of the Scottish Episcopal Church began in 1582 in the reign of James VI over disagreements about the role of bishops.
The oldestsurviving Anglican church building outside the British Isles Britain and Ireland is St Peter's Church in St. George's, Bermuda, established in 1612 though the actual building had to be rebuilt several times over the following century. This is also the olde
|
st surviving nonRoman Catholic church in the New World. It remained part of the Church of England until 1978 when the Anglican Church of Bermuda separated. The Church of England was the established church not only in England, but in its transOceanic colonies.
Thus the only member churches of the present Anglican Communion existing by the mid18th century were the Church of England, its closely linked sister church the Church of Ireland which also separated from Roman Catholicism under Henry VIII and the Scottish Episcopal Church which for parts of the 17th and 18th centuries was partially underground it was suspected of Jacobite sympathies.
Global spread of Anglicanism
The enormous expansion in the 18th and 19th centuries of the British Empire brought Anglicanism along with it. At first all these colonial churches were under the jurisdiction of the bishop of London. After the American Revolution, the parishes in the newly independent country found it necessary to break formally from a church whose supreme g
|
overnor was and remains the British monarch. Thus they formed their own dioceses and national church, the Episcopal Church in the United States of America, in a mostly amicable separation.
At about the same time, in the colonies which remained linked to the crown, the Church of England began to appoint colonial bishops. In 1787, a bishop of Nova Scotia was appointed with a jurisdiction over all of British North America; in time several more colleagues were appointed to other cities in presentday Canada. In 1814, a bishop of Calcutta was made; in 1824 the first bishop was sent to the West Indies and in 1836 to Australia. By 1840 there were still only ten colonial bishops for the Church of England; but even this small beginning greatly facilitated the growth of Anglicanism around the world. In 1841, a "Colonial Bishoprics Council" was set up and soon many more dioceses were created.
In time, it became natural to group these into provinces and a metropolitan bishop was appointed for each province. Although it
|
had at first been somewhat established in many colonies, in 1861 it was ruled that, except where specifically established, the Church of England had just the same legal position as any other church. Thus a colonial bishop and colonial diocese was by nature quite a different thing from their counterparts back home. In time bishops came to be appointed locally rather than from England and eventually national synods began to pass ecclesiastical legislation independent of England.
A crucial step in the development of the modern communion was the idea of the Lambeth Conferences discussed above. These conferences demonstrated that the bishops of disparate churches could manifest the unity of the church in their episcopal collegiality despite the absence of universal legal ties. Some bishops were initially reluctant to attend, fearing that the meeting would declare itself a council with power to legislate for the church; but it agreed to pass only advisory resolutions. These Lambeth Conferences have been held rough
|
ly every 10 years since 1878 the second such conference and remain the most visible comingtogether of the whole Communion.
The Lambeth Conference of 1998 included what has been seen by Philip Jenkins and others as a "watershed in global Christianity". The 1998 Lambeth Conference considered the issue of the theology of samesex attraction in relation to human sexuality. At this 1998 conference for the first time in centuries the Christians of developing regions, especially, Africa, Asia, and Latin America, prevailed over the bishops of more prosperous countries many from the US, Canada, and the UK who supported a redefinition of Anglican doctrine. Seen in this light 1998 is a date that marked the shift from a Westdominated Christianity to one wherein the growing churches of the twothirds world are predominant, but the gay bishop controversy in subsequent years led to the reassertion of Western dominance, this time of the liberal variety.
Ecumenical relations
Historic episcopate
The churches of the Anglican C
|
ommunion have traditionally held that ordination in the historic episcopate is a core element in the validity of clerical ordinations. The Roman Catholic Church, however, does not recognise Anglican orders see Apostolicae curae. Some Eastern Orthodox churches have issued statements to the effect that Anglican orders could be accepted, yet have still reordained former Anglican clergy; other Eastern Orthodox churches have rejected Anglican orders altogether. Orthodox bishop Kallistos Ware explains this apparent discrepancy as follows
Controversies
One effect of the Communion's dispersed authority has been the conflicts arising over divergent practices and doctrines in parts of the Communion. Disputes that had been confined to the Church of England could be dealt with legislatively in that realm, but as the Communion spread out into new nations and disparate cultures, such controversies multiplied and intensified. These controversies have generally been of two types liturgical and social.
AngloCatholicism
The
|
first such controversy of note concerned that of the growing influence of the Catholic Revival manifested in the Tractarian and socalled Ritualist controversies of the late nineteenth and early twentieth centuries. This controversy produced the Free Church of England and, in the United States and Canada, the Reformed Episcopal Church.
Social changes
Later, rapid social change and the dissipation of British cultural hegemony over its former colonies contributed to disputes over the role of women, the parameters of marriage and divorce, and the practices of contraception and abortion. In the late 1970s, the Continuing Anglican movement produced a number of new church bodies in opposition to women's ordination, prayer book changes, and the new understandings concerning marriage.
Samesex unions and LGBT clergy
More recently, disagreements over homosexuality have strained the unity of the communion as well as its relationships with other Christian denominations, leading to another round of withdrawals from the
|
Anglican Communion. Some churches were founded outside the Anglican Communion in the late 20th and early 21st centuries, largely in opposition to the ordination of openly homosexual bishops and other clergy and are usually referred to as belonging to the Anglican realignment movement, or else as "orthodox" Anglicans. These disagreements were especially noted when the Episcopal Church US consecrated an openly gay bishop in a samesex relationship, Gene Robinson, in 2003, which led some Episcopalians to defect and found the Anglican Church in North America ACNA; then, the debate reignited when the Church of England agreed to allow clergy to enter into samesex civil partnerships, as long as they remained celibate, in 2005. The Church of Nigeria opposed the Episcopal Church's decision as well as the Church of England's approval for celibate civil partnerships.
"The more liberal provinces that are open to changing Church doctrine on marriage in order to allow for samesex unions include Brazil, Canada, New Zealand,
|
Scotland, South India, South Africa, the US and Wales". The Church of England does not allow samegender marriages or blessing rites, but does permit special prayer services for samesex couples following a civil marriage or partnership. The Church of England also permits clergy to enter into samesex civil partnerships. The Church of Ireland has no official position on civil unions, and one senior cleric has entered into a samesex civil partnership. The Church of Ireland recognised that it will "treat civil partners the same as spouses". The Anglican Church of Australia does not have an official position on homosexuality.
The conservative Anglican churches, encouraging the realignment movement, are more concentrated in the Global South. For example, the Anglican Church of Kenya, the Church of Nigeria and the Church of Uganda have opposed homosexuality. GAFCON, a fellowship of conservative Anglican churches, has appointed "missionary bishops" in response to the disagreements with the perceived liberalisation i
|
n the Anglican churches in North America and Europe.
Debates about social theology and ethics have occurred at the same time as debates on prayer book revision and the acceptable grounds for achieving full communion with nonAnglican churches.
See also
Acts of Supremacy
English Reformation
Dissolution of the Monasteries
Ritualism in the Church of England
Apostolicae curae
Affirming Catholicism
Anglican ministry
AngloCatholicism
British Israelism
Church Society
Church's Ministry Among Jewish People
Compass rose
Evangelical Anglicanism
Flag of the Anglican Communion
Liberal AngloCatholicism
List of conservative evangelical Anglican churches in England
List of heroes of the Christian Church in the Anglican Communion
List of the largest Protestant bodies
Reform Anglican
Anglican Use
Notes
References
Citations
Sources
Further reading
Buchanan, Colin. Historical Dictionary of Anglicanism 2nd ed. 2015 excerpt
Hebert, A. G. The Form of the Church. London Faber and Faber, 1944.
Wild,
|
John. What is the Anglican Communion?, in series, The Advent Papers. Cincinnati, Ohio Forward Movement Publications, 196. Note. Expresses the "AngloCatholic" viewpoint.
External links
Anglicans Online
Project Canterbury Anglican historical documents from around the world
Brief description and history of the Anglican Communion 1997 article from the Anglican Communion Office
1867 establishments in England
Religious organizations established in 1867
Religion in the British Empire
|
Arne Kaijser born 1950 is a professor emeritus of history of technology at the KTH Royal Institute of Technology in Stockholm, and a former president of the Society for the History of Technology.
Kaijser has published two books in Swedish Stadens ljus. Etableringen av de frsta svenska gasverken and I fdrens spr. Den svenska infrastrukturens historiska utveckling och framtida utmaningar, and has coedited several anthologies. Kaijser is a member of the Royal Swedish Academy of Engineering Sciences since 2007 and also a member of the editorial board of two scientific journals Journal of Urban Technology and Centaurus. Lately, he has been occupied with the history of Large Technical Systems.
References
External links
Homepage
Extended homepage
1950 births
Living people
Swedish historians
KTH Royal Institute of Technology faculty
Members of the Royal Swedish Academy of Engineering Sciences
Historians of science
Historians of technology
Linkping University alumni
|
An archipelago , sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands.
Examples of archipelagos include the Indonesian Archipelago, the Andaman and Nicobar Islands, the Lakshadweep Islands, the Galpagos Islands, the Japanese Archipelago, the Philippine Archipelago, the Maldives, the Balearic Isles, the Bahamas, the Aegean Islands, the Hawaiian Islands, the Canary Islands, Malta, the Azores, the Canadian Arctic Archipelago, the British Isles, the islands of the Archipelago Sea, and Shetland. They are sometimes defined by political boundaries. The Gulf archipelago off the northeastern Pacific coast forms part of a larger archipelago that geographically includes Washington state's San Juan Islands. While the Gulf archipelago and San Juan Islands are geographically related, they are not technically included in the same archipelago due to manmade geopolitical borders.
Etymology
The word archipelago is d
|
erived from the Ancient Greek arkhi, "chief" and plagos, "sea" through the Italian arcipelago. In antiquity, "Archipelago" from medieval Greek and Latin was the proper name for the Aegean Sea. Later, usage shifted to refer to the Aegean Islands since the sea has a large number of islands.
Geographic types
Archipelagos may be found isolated in large amounts of water or neighbouring a large land mass. For example, Scotland has more than 700 islands surrounding its mainland which form an archipelago.
Archipelagos are often volcanic, forming along island arcs generated by subduction zones or hotspots, but may also be the result of erosion, deposition, and land elevation. Depending on their geological origin, islands forming archipelagos can be referred to as oceanic islands, continental fragments, and continental islands.
Oceanic islands
Oceanic islands are mainly of volcanic origin, and widely separated from any adjacent continent. The Hawaiian Islands and Easter Island in the Pacific, and le Amsterdam in
|
the south Indian Ocean are examples.
Continental fragments
Continental fragments correspond to land masses that have separated from a continental mass due to tectonic displacement. The Farallon Islands off the coast of California are an example.
Continental archipelagos
Sets of islands formed close to the coast of a continent are considered continental archipelagos when they form part of the same continental shelf, when those islands are abovewater extensions of the shelf. The islands of the Inside Passage off the coast of British Columbia and the Canadian Arctic Archipelago are examples.
Artificial archipelagos
Artificial archipelagos have been created in various countries for different purposes. Palm Islands and the World Islands off Dubai were or are being created for leisure and tourism purposes. Marker Wadden in the Netherlands is being built as a conservation area for birds and other wildlife.
Further examples
The largest archipelagic state in the world by area, and by population, is Indonesia.
Se
|
e also
Island arc
List of landforms
List of archipelagos by number of islands
List of archipelagos
Archipelagic state
List of islands
Aquapelago
References
External links
30 Most Incredible Island Archipelagos
Coastal and oceanic landforms
Oceanographical terminology
|
An author is the creator or originator of any written work such as a book or play, and is also considered a writer or poet. More broadly defined, an author is "the person who originated or gave existence to anything" and whose authorship determines responsibility for what was created.
Legal significance of authorship
Typically, the first owner of a copyright is the person who created the work, i.e. the author. If more than one person created the work, then a case of joint authorship can be made provided some criteria are met. In the copyright laws of various jurisdictions, there is a necessity for little flexibility regarding what constitutes authorship. The United States Copyright Office, for example, defines copyright as "a form of protection provided by the laws of the United States title 17, U.S. Code to authors of 'original works of authorship.'"
Holding the title of "author" over any "literary, dramatic, musical, artistic, or certain other intellectual works" gives rights to this person, the owner of
|
the copyright, especially the exclusive right to engage in or authorize any production or distribution of their work. Any person or entity wishing to use intellectual property held under copyright must receive permission from the copyright holder to use this work, and often will be asked to pay for the use of copyrighted material. After a fixed amount of time, the copyright expires on intellectual work and it enters the public domain, where it can be used without limit. Copyright laws in many jurisdictions mostly following the lead of the United States, in which the entertainment and publishing industries have very strong lobbying power have been amended repeatedly since their inception, to extend the length of this fixed period where the work is exclusively controlled by the copyright holder. However, copyright is merely the legal reassurance that one owns their work. Technically, someone owns their work from the time it's created. A notable aspect of authorship emerges with copyright in that, in many juri
|
sdictions, it can be passed down to another upon one's death. The person who inherits the copyright is not the author, but enjoys the same legal benefits.
Questions arise as to the application of copyright law. How does it, for example, apply to the complex issue of fan fiction? If the media agency responsible for the authorized production allows material from fans, what is the limit before legal constraints from actors, music, and other considerations, come into play? Additionally, how does copyright apply to fangenerated stories for books? What powers do the original authors, as well as the publishers, have in regulating or even stopping the fan fiction? This particular sort of case also illustrates how complex intellectual property law can be, since such fiction may also involved trademark law e.g. for names of characters in media franchises, likeness rights such as for actors, or even entirely fictional entities, fair use rights held by the public including the right to parody or satirize, and many oth
|
er interacting complications.
Authors may portion out different rights they hold to different parties, at different times, and for different purposes or uses, such as the right to adapt a plot into a film, but only with different character names, because the characters have already been optioned by another company for a television series or a video game. An author may also not have rights when working under contract that they would otherwise have, such as when creating a work for hire e.g., hired to write a city tour guide by a municipal government that totally owns the copyright to the finished work, or when writing material using intellectual property owned by others such as when writing a novel or screenplay that is a new installment in an already established media franchise.
Philosophical views of the nature of authorship
In literary theory, critics find complications in the term author beyond what constitutes authorship in a legal setting. In the wake of postmodern literature, critics such as Roland
|
Barthes and Michel Foucault have examined the role and relevance of authorship to the meaning or interpretation of a text.
Barthes challenges the idea that a text can be attributed to any single author. He writes, in his essay "Death of the Author" 1968, that "it is language which speaks, not the author." The words and language of a text itself determine and expose meaning for Barthes, and not someone possessing legal responsibility for the process of its production. Every line of written text is a mere reflection of references from any of a multitude of traditions, or, as Barthes puts it, "the text is a tissue of quotations drawn from the innumerable centres of culture"; it is never original. With this, the perspective of the author is removed from the text, and the limits formerly imposed by the idea of one authorial voice, one ultimate and universal meaning, are destroyed. The explanation and meaning of a work does not have to be sought in the one who produced it, "as if it were always in the end, through
|
the more or less transparent allegory of the fiction, the voice of a single person, the author 'confiding' in us." The psyche, culture, fanaticism of an author can be disregarded when interpreting a text, because the words are rich enough themselves with all of the traditions of language. To expose meanings in a written work without appealing to the celebrity of an author, their tastes, passions, vices, is, to Barthes, to allow language to speak, rather than author.
Michel Foucault argues in his essay "What is an author?" 1969 that all authors are writers, but not all writers are authors. He states that "a private letter may have a signatoryit does not have an author." For a reader to assign the title of author upon any written work is to attribute certain standards upon the text which, for Foucault, are working in conjunction with the idea of "the author function." Foucault's author function is the idea that an author exists only as a function of a written work, a part of its structure, but not necessarily
|
part of the interpretive process. The author's name "indicates the status of the discourse within a society and culture," and at one time was used as an anchor for interpreting a text, a practice which Barthes would argue is not a particularly relevant or valid endeavour.
Expanding upon Foucault's position, Alexander Nehamas writes that Foucault suggests "an author ... is whoever can be understood to have produced a particular text as we interpret it," not necessarily who penned the text. It is this distinction between producing a written work and producing the interpretation or meaning in a written work that both Barthes and Foucault are interested in. Foucault warns of the risks of keeping the author's name in mind during interpretation, because it could affect the value and meaning with which one handles an interpretation.
Literary critics Barthes and Foucault suggest that readers should not rely on or look for the notion of one overarching voice when interpreting a written work, because of the complica
|
tions inherent with a writer's title of "author." They warn of the dangers interpretations could suffer from when associating the subject of inherently meaningful words and language with the personality of one authorial voice. Instead, readers should allow a text to be interpreted in terms of the language as "author."
Relationship with publisher
Selfpublishing
Selfpublishing, selfpublishing, independent publishing, or artisanal publishing is the "publication of any book, album or other media by its author without the involvement of a traditional publisher. It is the modern equivalent to traditional publishing."
Types
Unless a book is to be sold directly from the author to the public, an ISBN is required to uniquely identify the title. ISBN is a global standard used for all titles worldwide. Most selfpublishing companies either provide their own ISBN to a title or can provide direction; it may be in the best interest of the selfpublished author to retain ownership of ISBN and copyright instead of using a n
|
umber owned by a vanity press. A separate ISBN is needed for each edition of the book.
Electronic ebook publishing
There are a variety of book formats and tools that can be used to create them. Because it is possible to create ebooks with no upfront or perbook costs, this is a popular option for selfpublishers. Ebook publishing platforms include Pronoun, Smashwords, Blurb, Amazon Kindle Direct Publishing, CinnamonTeal Publishing, Papyrus Editor, ebook leap, Bookbaby, Pubit, Lulu, Llumina Press, and CreateSpace. Ebook formats include epub, mobi, and PDF, among others.
Printondemand
Printondemand POD publishing refers to the ability to print highquality books as needed. For selfpublished books, this is often a more economical option than conducting a print run of hundreds or thousands of books. Many companies, such as Createspace owned by Amazon.com, Outskirts Press, Blurb, Lulu, Llumina Press, ReadersMagnet, and iUniverse, allow printing single books at perbook costs not much higher than those paid by pub
|
lishing companies for large print runs.
Traditional publishing
With commissioned publishing, the publisher makes all the publication arrangements and the author covers all expenses.
The author of a work may receive a percentage calculated on a wholesale or a specific price or a fixed amount on each book sold. Publishers, at times, reduced the risk of this type of arrangement, by agreeing only to pay this after a certain number of copies had sold. In Canada, this practice occurred during the 1890s, but was not commonplace until the 1920s. Established and successful authors may receive advance payments, set against future royalties, but this is no longer common practice. Most independent publishers pay royalties as a percentage of net receipts how net receipts are calculated varies from publisher to publisher. Under this arrangement, the author does not pay anything towards the expense of publication. The costs and financial risk are all carried by the publisher, who will then take the greatest percentage of
|
the receipts. See Compensation for more.
Vanity publishing
This type of publisher normally charges a flat fee for arranging publication, offers a platform for selling, and then takes a percentage of the sale of every copy of a book. The author receives the rest of the money made.
Relationship with editor
The relationship between the author and the editor, often the author's only liaison to the publishing company, is often characterized as the site of tension. For the author to reach their audience, often through publication, the work usually must attract the attention of the editor. The idea of the author as the sole meaningmaker of necessity changes to include the influences of the editor and the publisher in order to engage the audience in writing as a social act. There are three principal areas covered by editors Proofing checking the Grammar and spelling, looking for typing errors, Story potentially an area of deep angst for both author and publisher, and Layout the setting of the final proof ready fo
|
r publishing often requires minor text changes so a layout editor is required to ensure that these do not alter the sense of the text.
Pierre Bourdieu's essay "The Field of Cultural Production" depicts the publishing industry as a "space of literary or artistic positiontakings," also called the "field of struggles," which is defined by the tension and movement inherent among the various positions in the field. Bourdieu claims that the "field of positiontakings ... is not the product of coherenceseeking intention or objective consensus," meaning that an industry characterized by positiontakings is not one of harmony and neutrality. In particular for the writer, their authorship in their work makes their work part of their identity, and there is much at stake personally over the negotiation of authority over that identity. However, it is the editor who has "the power to impose the dominant definition of the writer and therefore to delimit the population of those entitled to take part in the struggle to define
|
the writer". As "cultural investors," publishers rely on the editor position to identify a good investment in "cultural capital" which may grow to yield economic capital across all positions.
According to the studies of James Curran, the system of shared values among editors in Britain has generated a pressure among authors to write to fit the editors' expectations, removing the focus from the readeraudience and putting a strain on the relationship between authors and editors and on writing as a social act. Even the book review by the editors has more significance than the readership's reception.
Compensation
Authors rely on advance fees, royalty payments, adaptation of work to a screenplay, and fees collected from giving speeches.
A standard contract for an author will usually include provision for payment in the form of an advance and royalties. An advance is a lump sum paid in advance of publication. An advance must be earned out before royalties are payable. An advance may be paid in two lump sums the
|
first payment on contract signing, and the second on delivery of the completed manuscript or on publication.
Royalty payment is the sum paid to authors for each copy of a book sold and is traditionally around 1012, but selfpublished authors can earn about 40 60 royalties per each book sale. An author's contract may specify, for example, that they will earn 10 of the retail price of each book sold. Some contracts specify a scale of royalties payable for example, where royalties start at 10 for the first 10,000 sales, but then increase to a higher percentage rate at higher sale thresholds.
An author's book must earn the advance before any further royalties are paid. For example, if an author is paid a modest advance of 2000, and their royalty rate is 10 of a book priced at 20 that is, 2 per book the book will need to sell 1000 copies before any further payment will be made. Publishers typically withhold payment of a percentage of royalties earned against returns.
In some countries, authors also earn inco
|
me from a government scheme such as the ELR educational lending right and PLR public lending right schemes in Australia. Under these schemes, authors are paid a fee for the number of copies of their books in educational andor public libraries.
These days, many authors supplement their income from book sales with public speaking engagements, school visits, residencies, grants, and teaching positions.
Ghostwriters, technical writers, and textbooks writers are typically paid in a different way usually a set fee or a per word rate rather than on a percentage of sales.
In the year 2016, according to the U.S. Bureau of Labor Statistics, nearly 130,000 people worked in the U.S. as authors making an average of 61,240 per year.
See also
Academic authorship
Auteur
Authors' editor
Distributive writing
Lead author
List of novelists
Lists of poets
Lists of writers
Novelist
Professional writing
References
Writing occupations
Literary criticism
|
Andrey Andreyevich Markov 14 June 1856 20 July 1922 was a Russian mathematician best known for his work on stochastic processes. A primary subject of his research later became known as Markov chains or Markov processes.
Markov and his younger brother Vladimir Andreevich Markov 18711897 proved the Markov brothers' inequality.
His son, another Andrey Andreyevich Markov 19031979, was also a notable mathematician, making contributions to constructive mathematics and recursive function theory.
Biography
Andrey Markov was born on 14 June 1856 in Russia. He attended the St. Petersburg Grammar School, where some teachers saw him as a rebellious student. In his academics he performed poorly in most subjects other than mathematics. Later in life he attended Saint Petersburg Imperial University now Saint Petersburg State University. among his teachers were Yulian Sokhotski differential calculus, higher algebra, Konstantin Posse analytic geometry, Yegor Zolotarev integral calculus, Pafnuty Chebyshev number theory an
|
d probability theory, Aleksandr Korkin ordinary and partial differential equations, Mikhail Okatov mechanism theory, Osip Somov mechanics, and Nikolai Budajev descriptive and higher geometry. He completed his studies at the university and was later asked if he would like to stay and have a career as a Mathematician. He later taught at high schools and continued his own mathematical studies. In this time he found a practical use for his mathematical skills. He figured out that he could use chains to model the alliteration of vowels and consonants in Russian literature. He also contributed to many other mathematical aspects in his time. He died at age 66 on 20 July 1922.
Timeline
In 1877, Markov was awarded a gold medal for his outstanding solution of the problem
About Integration of Differential Equations by Continued Fractions with an Application to the Equation .
During the following year, he passed the candidate's examinations, and he remained at the university to prepare for a lecturer's position.
In
|
April 1880, Markov defended his master's thesis "On the Binary Square Forms with Positive Determinant", which was directed by Aleksandr Korkin and Yegor Zolotarev. Four years later in 1884, he defended his doctoral thesis titled "On Certain Applications of the Algebraic Continuous Fractions".
His pedagogical work began after the defense of his master's thesis in autumn 1880. As a privatdozent he lectured on differential and integral calculus. Later he lectured alternately on "introduction to analysis", probability theory succeeding Chebyshev, who had left the university in 1882 and the calculus of differences. From 1895 through 1905 he also lectured in differential calculus.
One year after the defense of his doctoral thesis, Markov was appointed extraordinary professor 1886 and in the same year he was elected adjunct to the Academy of Sciences. In 1890, after the death of Viktor Bunyakovsky, Markov became an extraordinary member of the academy. His promotion to an ordinary professor of St. Petersburg Unive
|
rsity followed in the fall of 1894.
In 1896, Markov was elected an ordinary member of the academy as the successor of Chebyshev. In 1905, he was appointed merited professor and was granted the right to retire, which he did immediately. Until 1910, however, he continued to lecture in the calculus of differences.
In connection with student riots in 1908, professors and lecturers of St. Petersburg University were ordered to monitor their students. Markov refused to accept this decree, and he wrote an explanation in which he declined to be an "agent of the governance". Markov was removed from further teaching duties at St. Petersburg University, and hence he decided to retire from the university.
Markov was an atheist. In 1912, he protested Leo Tolstoy's excommunication from the Russian Orthodox Church by requesting his own excommunication. The Church complied with his request.
In 1913, the council of St. Petersburg elected nine scientists honorary members of the university. Markov was among them, but his ele
|
ction was not affirmed by the minister of education. The affirmation only occurred four years later, after the February Revolution in 1917. Markov then resumed his teaching activities and lectured on probability theory and the calculus of differences until his death in 1922.
See also
List of things named after Andrey Markov
ChebyshevMarkovStieltjes inequalities
GaussMarkov theorem
GaussMarkov process
Hidden Markov model
Markov blanket
Markov chain
Markov decision process
Markov's inequality
Markov brothers' inequality
Markov information source
Markov network
Markov number
Markov property
Markov process
Stochastic matrix also known as Markov matrix
Subjunctive possibility
Notes
References
Further reading
. . . " , ". " ", 2 , 15, . 135156, 1906.
A. A. Markov. "Extension of the limit theorems of probability theory to a sum of variables connected in a chain". reprinted in Appendix B of R. Howard. Dynamic Probabilistic Systems, volume 1 Markov Chains. John Wiley and Sons,
|
1971.
External links
Markov, Andrei Andreyevich
Markov, Andrei Andreyevich
19thcentury Russian mathematicians
20thcentury Russian mathematicians
Russian atheists
Former Russian Orthodox Christians
Probability theorists
Saint Petersburg State University alumni
Full members of the Saint Petersburg Academy of Sciences
Full Members of the Russian Academy of Sciences 19171925
People from Ryazan
Russian statisticians
|
Angst is fear or anxiety anguish is its Latinate equivalent, and the words anxious and anxiety are of similar origin. The dictionary definition for angst is a feeling of anxiety, apprehension, or insecurity.
Etymology
The word angst was introduced into English from the Danish, Norwegian, and Dutch word and the German word . It is attested since the 19th century in English translations of the works of Kierkegaard and Freud. It is used in English to describe an intense feeling of apprehension, anxiety, or inner turmoil.
In other languages with words from the Latin for "fear" or "panic", the derived words differ in meaning; for example, as in the French and . The word angst has existed since the 8th century, from the ProtoIndoEuropean root , "restraint" from which Old High German developed. It is precognate with the Latin , "tensity, tightness" and , "choking, clogging"; compare to the Ancient Greek "strangle".
Existentialist angst
In existentialist philosophy, the term angst carries a specific concep
|
tual meaning. The use of the term was first attributed to Danish philosopher Sren Kierkegaard 18131855. In The Concept of Anxiety also known as The Concept of Dread, depending on the translation, Kierkegaard used the word Angest in common Danish, angst, meaning "dread" or "anxiety" to describe a profound and deepseated condition. Where nonhuman animals are guided solely by instinct, said Kierkegaard, human beings enjoy a freedom of choice that we find both appealing and terrifying. It is the anxiety of understanding of being free when considering undefined possibilities of one's life and the immense responsibility of having the power of choice over them. Kierkegaard's concept of angst reappeared in the works of existentialist philosophers who followed, such as Friedrich Nietzsche, JeanPaul Sartre, and Martin Heidegger, each of whom developed the idea further in individual ways. While Kierkegaard's angst referred mainly to ambiguous feelings about moral freedom within a religious personal belief system, later
|
existentialists discussed conflicts of personal principles, cultural norms, and existential despair.
Music
Existential angst makes its appearance in classical musical composition in the early twentieth century as a result of both philosophical developments and as a reflection of the wartorn times. Notable composers whose works are often linked with the concept include Gustav Mahler, Richard Strauss operas Elektra and Salome, ClaudeAchille Debussy opera Pelleas et Melisande, ballet Jeux, other works, Jean Sibelius especially the Fourth Symphony, Arnold Schoenberg A Survivor from Warsaw, other works, Alban Berg, Francis Poulenc opera Dialogues of the Carmelites, Dmitri Shostakovich opera Lady Macbeth of the Mtsensk District, symphonies and chamber music, Bla Bartk opera Bluebeard's Castle, other works, and Krzysztof Penderecki especially Threnody to the Victims of Hiroshima.
Angst began to be discussed in reference to popular music in the mid to late 1950s amid widespread concerns over international tension
|
s and nuclear proliferation. Jeff Nuttall's book Bomb Culture 1968 traced angst in popular culture to Hiroshima. Dread was expressed in works of folk rock such as Bob Dylan's "Masters of War" 1963 and "A Hard Rain's aGonna Fall". The term often makes an appearance in reference to punk rock, grunge, nu metal, and works of emo where expressions of melancholy, existential despair, or nihilism predominate.
See also
References
External links
Anxiety
Emotions
Existentialist concepts
|
Anxiety is an emotion characterized by an unpleasant state of inner turmoil and includes subjectively unpleasant feelings of dread over anticipated events. It is often accompanied by nervous behavior such as pacing back and forth, somatic complaints, and rumination.
Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing. It is often accompanied by muscular tension, restlessness, fatigue, inability to catch one's breath, tightness in the abdominal region, and problems in concentration. Anxiety is closely related to fear, which is a response to a real or perceived immediate threat; anxiety involves the expectation of future threat including dread. People facing anxiety may withdraw from situations which have provoked anxiety in the past.
Though anxiety is a normal human response, when excessive or persisting beyond developmentally appropriate periods it may be diagnosed as an anxiety disorder. There are multi
|
ple forms of anxiety disorder such as Generalized Anxiety Disorder and Obsessive Compulsive Disorder with specific clinical definitions. Part of the definition of an anxiety disorder, which distinguishes it from every day anxiety, is that it is persistent, typically lasting 6 months or more, although the criterion for duration is intended as a general guide with allowance for some degree of flexibility and is sometimes of shorter duration in children.
Anxiety vs. fear
Anxiety is distinguished from fear, which is an appropriate cognitive and emotional response to a perceived threat. Anxiety is related to the specific behaviors of fightorflight responses, defensive behavior or escape. There is a false presumption that often circulates that anxiety only occurs in situations perceived as uncontrollable or unavoidable, but this is not always so. David Barlow defines anxiety as "a futureoriented mood state in which one is not ready or prepared to attempt to cope with upcoming negative events," and that it is a dis
|
tinction between future and present dangers which divides anxiety and fear. Another description of anxiety is agony, dread, terror, or even apprehension. In positive psychology, anxiety is described as the mental state that results from a difficult challenge for which the subject has insufficient coping skills.
Fear and anxiety can be differentiated into four domains 1 duration of emotional experience, 2 temporal focus, 3 specificity of the threat, and 4 motivated direction. Fear is shortlived, presentfocused, geared towards a specific threat, and facilitating escape from threat. On the other hand, anxiety is longacting, futurefocused, broadly focused towards a diffuse threat, and promoting excessive caution while approaching a potential threat and interferes with constructive coping.
Joseph E. LeDoux and Lisa Feldman Barrett have both sought to separate automatic threat responses from additional associated cognitive activity within anxiety.
Symptoms
Anxiety can be experienced with long, drawnout daily sym
|
ptoms that reduce quality of life, known as chronic or generalized anxiety, or it can be experienced in short spurts with sporadic, stressful panic attacks, known as acute anxiety. Symptoms of anxiety can range in number, intensity, and frequency, depending on the person. While almost everyone has experienced anxiety at some point in their lives, most do not develop longterm problems with anxiety.
Anxiety may cause psychiatric and physiological symptoms.
The risk of anxiety leading to depression could possibly even lead to an individual harming themselves, which is why there are many 24hour suicide prevention hotlines.
The behavioral effects of anxiety may include withdrawal from situations which have provoked anxiety or negative feelings in the past. Other effects may include changes in sleeping patterns, changes in habits, increase or decrease in food intake, and increased motor tension such as foot tapping.
The emotional effects of anxiety may include "feelings of apprehension or dread, trouble concent
|
rating, feeling tense or jumpy, anticipating the worst, irritability, restlessness, watching and waiting for signs and occurrences of danger, and, feeling like your mind's gone blank" as well as "nightmaresbad dreams, obsessions about sensations, dj vu, a trappedinyourmind feeling, and feeling like everything is scary." It may include a vague experience and feeling of helplessness.
The cognitive effects of anxiety may include thoughts about suspected dangers, such as fear of dying "You may ... fear that the chest pains are a deadly heart attack or that the shooting pains in your head are the result of a tumor or an aneurysm. You feel an intense fear when you think of dying, or you may think of it more often than normal, or can't get it out of your mind."
The physiological symptoms of anxiety may include
Neurological, as headache, paresthesias, fasciculations, vertigo, or presyncope.
Digestive, as abdominal pain, nausea, diarrhea, indigestion, dry mouth, or bolus. Stress hormones released in an anxious sta
|
te have an impact on bowel function and can manifest physical symptoms that may contribute to or exacerbate IBS.
Respiratory, as shortness of breath or sighing breathing.
Cardiac, as palpitations, tachycardia, or chest pain.
Muscular, as fatigue, tremors, or tetany.
Cutaneous, as perspiration, or itchy skin.
Urogenital, as frequent urination, urinary urgency, dyspareunia, or impotence, chronic pelvic pain syndrome.
Types
There are various types of anxiety. Existential anxiety can occur when a person faces angst, an existential crisis, or nihilistic feelings. People can also face mathematical anxiety, somatic anxiety, stage fright, or test anxiety. Social anxiety refers to a fear of rejection and negative evaluation being judged by other people.
Existential
The philosopher Sren Kierkegaard, in The Concept of Anxiety 1844, described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the selfconscious exercise of responsibility
|
and choosing. In Art and Artist 1932, the psychologist Otto Rank wrote that the psychological trauma of birth was the preeminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of and desire for separation, individuation, and differentiation.
The theologian Paul Tillich characterized existential anxiety as "the state in which a being is aware of its possible nonbeing" and he listed three categories for the nonbeing and resulting anxiety ontic fate and death, moral guilt and condemnation, and spiritual emptiness and meaninglessness. According to Tillich, the last of these three types of existential anxiety, i.e. spiritual anxiety, is predominant in modern times while the others were predominant in earlier periods. Tillich argues that this anxiety can be accepted as part of the human condition or it can be resisted but with negative consequences. In its pathological form, spiritual anxiety may tend to "drive the person toward the creation of certitude in systems o
|
f meaning which are supported by tradition and authority" even though such "undoubted certitude is not built on the rock of reality".
According to Viktor Frankl, the author of Man's Search for Meaning, when a person is faced with extreme mortal dangers, the most basic of all human wishes is to find a meaning of life to combat the "trauma of nonbeing" as death is near.
Depending on the source of the threat, psychoanalytic theory distinguishes the following types of anxiety
realistic
neurotic
moral
Test and performance
According to YerkesDodson law, an optimal level of arousal is necessary to best complete a task such as an exam, performance, or competitive event. However, when the anxiety or level of arousal exceeds that optimum, the result is a decline in performance.
Test anxiety is the uneasiness, apprehension, or nervousness felt by students who have a fear of failing an exam. Students who have test anxiety may experience any of the following the association of grades with personal worth; fear of
|
embarrassment by a teacher; fear of alienation from parents or friends; time pressures; or feeling a loss of control. Sweating, dizziness, headaches, racing heartbeats, nausea, fidgeting, uncontrollable crying or laughing and drumming on a desk are all common. Because test anxiety hinges on fear of negative evaluation, debate exists as to whether test anxiety is itself a unique anxiety disorder or whether it is a specific type of social phobia. The DSMIV classifies test anxiety as a type of social phobia.
While the term "test anxiety" refers specifically to students, many workers share the same experience with regard to their career or profession. The fear of failing at a task and being negatively evaluated for failure can have a similarly negative effect on the adult. Management of test anxiety focuses on achieving relaxation and developing mechanisms to manage anxiety.
Stranger, social, and intergroup anxiety
Humans generally require social acceptance and thus sometimes dread the disapproval of others. A
|
pprehension of being judged by others may cause anxiety in social environments.
Anxiety during social interactions, particularly between strangers, is common among young people. It may persist into adulthood and become social anxiety or social phobia. "Stranger anxiety" in small children is not considered a phobia. In adults, an excessive fear of other people is not a developmentally common stage; it is called social anxiety. According to Cutting, social phobics do not fear the crowd but the fact that they may be judged negatively.
Social anxiety varies in degree and severity. For some people, it is characterized by experiencing discomfort or awkwardness during physical social contact e.g. embracing, shaking hands, etc., while in other cases it can lead to a fear of interacting with unfamiliar people altogether. Those suffering from this condition may restrict their lifestyles to accommodate the anxiety, minimizing social interaction whenever possible. Social anxiety also forms a core aspect of certain pers
|
onality disorders, including avoidant personality disorder.
To the extent that a person is fearful of social encounters with unfamiliar others, some people may experience anxiety particularly during interactions with outgroup members, or people who share different group memberships i.e., by race, ethnicity, class, gender, etc.. Depending on the nature of the antecedent relations, cognitions, and situational factors, intergroup contact may be stressful and lead to feelings of anxiety. This apprehension or fear of contact with outgroup members is often called interracial or intergroup anxiety.
As is the case with the more generalized forms of social anxiety, intergroup anxiety has behavioral, cognitive, and affective effects. For instance, increases in schematic processing and simplified information processing can occur when anxiety is high. Indeed, such is consistent with related work on attentional bias in implicit memory. Additionally recent research has found that implicit racial evaluations i.e. automati
|
c prejudiced attitudes can be amplified during intergroup interaction. Negative experiences have been illustrated in producing not only negative expectations, but also avoidant, or antagonistic, behavior such as hostility. Furthermore, when compared to anxiety levels and cognitive effort e.g., impression management and selfpresentation in intragroup contexts, levels and depletion of resources may be exacerbated in the intergroup situation.
Trait
Anxiety can be either a shortterm "state" or a longterm personality "trait." Trait anxiety reflects a stable tendency across the lifespan of responding with acute, state anxiety in the anticipation of threatening situations whether they are actually deemed threatening or not. A metaanalysis showed that a high level of neuroticism is a risk factor for development of anxiety symptoms and disorders. Such anxiety may be conscious or unconscious.
Personality can also be a trait leading to anxiety and depression. Through experience, many find it difficult to collect thems
|
elves due to their own personal nature.
Choice or decision
Anxiety induced by the need to choose between similar options is increasingly being recognized as a problem for individuals and for organizations. In 2004, Capgemini wrote "Today we're all faced with greater choice, more competition and less time to consider our options or seek out the right advice."
In a decision context, unpredictability or uncertainty may trigger emotional responses in anxious individuals that systematically alter decisionmaking. There are primarily two forms of this anxiety type. The first form refers to a choice in which there are multiple potential outcomes with known or calculable probabilities. The second form refers to the uncertainty and ambiguity related to a decision context in which there are multiple possible outcomes with unknown probabilities.
Panic disorder
Panic disorder may share symptoms of stress and anxiety, but it is actually very different. Panic disorder is an anxiety disorder that occurs without any trig
|
gers. According to the U.S Department of Health and Human Services, this disorder can be distinguished by unexpected and repeated episodes of intense fear. Someone who suffers from panic disorder will eventually develop constant fear of another attack and as this progresses it will begin to affect daily functioning and an individual's general quality of life. It is reported by the Cleveland Clinic that panic disorder affects 2 to 3 percent of adult Americans and can begin around the time of the teenage and early adult years. Some symptoms include difficulty breathing, chest pain, dizziness, trembling or shaking, feeling faint, nausea, fear that you are losing control or are about to die. Even though they suffer from these symptoms during an attack, the main symptom is the persistent fear of having future panic attacks.
Anxiety disorders
Anxiety disorders are a group of mental disorders characterized by exaggerated feelings of anxiety and fear responses. Anxiety is a worry about future events and fear is a
|
reaction to current events. These feelings may cause physical symptoms, such as a fast heart rate and shakiness. There are a number of anxiety disorders including generalized anxiety disorder, specific phobia, social anxiety disorder, separation anxiety disorder, agoraphobia, panic disorder, and selective mutism. The disorder differs by what results in the symptoms. People often have more than one anxiety disorder.
Anxiety disorders are caused by a complex combination of genetic and environmental factors. To be diagnosed, symptoms typically need to be present for at least six months, be more than would be expected for the situation, and decrease a person's ability to function in their daily lives. Other problems that may result in similar symptoms include hyperthyroidism, heart disease, caffeine, alcohol, or cannabis use, and withdrawal from certain drugs, among others.
Without treatment, anxiety disorders tend to remain. Treatment may include lifestyle changes, counselling, and medications. Counselling is
|
typically with a type of cognitive behavioural therapy. Medications, such as antidepressants or beta blockers, may improve symptoms.
About 12 of people are affected by an anxiety disorder in a given year and between 530 are affected at some point in their life. They occur about twice as often in women than they do in men, and generally begin before the age of 25. The most common are specific phobia which affects nearly 12 and social anxiety disorder which affects 10 at some point in their life. They affect those between the ages of 15 and 35 the most and become less common after the age of 55. Rates appear to be higher in the United States and Europe.
Short and longterm anxiety
Anxiety can be either a shortterm "state" or a longterm "trait." Whereas trait anxiety represents worrying about future events, anxiety disorders are a group of mental disorders characterized by feelings of anxiety and fears.
Four Ways to Be Anxious
In his book Anxious the modern mind in the age of anxiety Joseph LeDoux examines fo
|
ur experiences of anxiety through a brainbased lens
In the presence of an existing or imminent external threat, you worry about the event and its implications for your physical andor psychological wellbeing. When a threat signal occurs, it signifies either that danger is present or near in space and time or that it might be coming in the future. Nonconscius threats processing by the brain activates defensive survival circuits, resulting in changes in information processing in the brain, controlled in part by increases in arousal and behavioral and physiological responses in the body that then produce signals that feed back to the brain and complement the physiological changes there, intensifying them and extending their duration.
When you notice body sensations, you worry about what they might mean for your physical andor psychological wellbeing. The trigger stimulus does not have to be an external stimulus but can be an internal one, as some people are particularly sensitive to body signals.
Thoughts an
|
d memories may lead to you to worry about your physical andor psychological wellbeing. We do not need to be presence of an external or internal stimulus to be anxious. An episodic memory of a past trauma or of a panic attack in the past is sufficient to activate the defence circuits.
Thoughts and memories may result in existential dread, such as worry about leading a meaningful life or the eventuality of death. Examples are contemplations of whether one's life has been meaningful, the inevitability of death, or the difficulty of making decisions that have a moral value. These do not necessarily activate defensive systems; they are more or less pure forms of cognitive anxiety.
Comorbidity
Anxiety disorders often occur with other mental health disorders, particularly major depressive disorder, bipolar disorder, eating disorders, or certain personality disorders. It also commonly occurs with personality traits such as neuroticism. This observed cooccurrence is partly due to genetic and environmental influences
|
shared between these traits and anxiety.
It is common for those with obsessivecompulsive disorder to experience anxiety. Anxiety is also commonly found in those who experience panic disorders, phobic anxiety disorders, severe stress, dissociative disorders, somatoform disorders, and some neurotic disorders.
Risk factors
Anxiety disorders are partly genetic, with twin studies suggesting 3040 genetic influence on individual differences in anxiety. Environmental factors are also important. Twin studies show that individualspecific environments have a large influence on anxiety, whereas shared environmental influences environments that affect twins in the same way operate during childhood but decline through adolescence. Specific measured environments that have been associated with anxiety include child abuse, family history of mental health disorders, and poverty. Anxiety is also associated with drug use, including alcohol, caffeine, and benzodiazepines which are often prescribed to treat anxiety.
Neuroanat
|
omy
Neural circuitry involving the amygdala which regulates emotions like anxiety and fear, stimulating the HPA axis and sympathetic nervous system and hippocampus which is implicated in emotional memory along with the amygdala is thought to underlie anxiety. People who have anxiety tend to show high activity in response to emotional stimuli in the amygdala. Some writers believe that excessive anxiety can lead to an overpotentiation of the limbic system which includes the amygdala and nucleus accumbens, giving increased future anxiety, but this does not appear to have been proven.
Research upon adolescents who as infants had been highly apprehensive, vigilant, and fearful finds that their nucleus accumbens is more sensitive than that in other people when deciding to make an action that determined whether they received a reward. This suggests a link between circuits responsible for fear and also reward in anxious people. As researchers note, "a sense of 'responsibility', or selfagency, in a context of uncerta
|
inty probabilistic outcomes drives the neural system underlying appetitive motivation i.e., nucleus accumbens more strongly in temperamentally inhibited than noninhibited adolescents".
The gutbrain axis
The microbes of the gut can connect with the brain to affect anxiety. There are various pathways along which this communication can take place. One is through the major neurotransmitters. The gut microbes such as Bifidobacterium and Bacillus produce the neurotransmitters GABA and dopamine, respectively. The neurotransmitters signal to the nervous system of the gastrointestinal tract, and those signals will be carried to the brain through the vagus nerve or the spinal system. This is demonstrated by the fact that altering the microbiome has shown anxiety and depressionreducing effects in mice, but not in subjects without vagus nerves.
Another key pathway is the HPA axis, as mentioned above. The microbes can control the levels of cytokines in the body, and altering cytokine levels creates direct effects on ar
|
eas of the brain such as the hypothalmus, the area that triggers HPA axis activity. The HPA axis regulates production of cortisol, a hormone that takes part in the body's stress response. When HPA activity spikes, cortisol levels increase, processing and reducing anxiety in stressful situations. These pathways, as well as the specific effects of individual taxa of microbes, are not yet completely clear, but the communication between the gut microbiome and the brain is undeniable, as is the ability of these pathways to alter anxiety levels.
With this communication comes the potential to treat anxiety. Prebiotics and probiotics have been shown to reduced anxiety. For example, experiments in which mice were given fructo and galactooligosaccharide prebiotics and Lactobacillus probiotics have both demonstrated a capability to reduce anxiety. In humans, results are not as concrete, but promising.
Genetics
Genetics and family history e.g. parental anxiety may put an individual at increased risk of an anxiety disor
|
der, but generally external stimuli will trigger its onset or exacerbation. Estimates of genetic influence on anxiety, based on studies of twins, range from 25 to 40 depending on the specific type and agegroup under study. For example, genetic differences account for about 43 of variance in panic disorder and 28 in generalized anxiety disorder. Longitudinal twin studies have shown the moderate stability of anxiety from childhood through to adulthood is mainly influenced by stability in genetic influence. When investigating how anxiety is passed on from parents to children, it is important to account for sharing of genes as well as environments, for example using the intergenerational childrenoftwins design.
Many studies in the past used a candidate gene approach to test whether single genes were associated with anxiety. These investigations were based on hypotheses about how certain known genes influence neurotransmitters such as serotonin and norepinephrine and hormones such as cortisol that are implicated
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.