Coordinates:

Niger or the Niger[11][12] (/niːˈʒɛər/ or /ˈnaɪdʒər/(listen);[13][14] French:[niʒɛʁ]), officially the Republic of the Niger,[11][12] is a landlocked country in West Africa named after the Niger River. Niger is bordered by Libya to the northeast, Chad to the east, Nigeria to the south, Benin to the southwest, Burkina Faso and Mali to the west, and Algeria to the northwest. Niger covers a land area of almost 1,270,000km2 (490,000sqmi), making it the largest country in West Africa. Over 80% of its land area lies in the Sahara Desert. The country's predominantly Islamic population of about 21 million[15] live mostly in clusters in the far south and west of the country. The capital city is Niamey, located in Niger's southwest corner.
Niger is a developing country, which consistently ranks near the bottom in the United Nations' Human Development Index (HDI); it was ranked 187th of 188 countries for 2015 and 189th out of 189 countries in the 2018 report.[16] Much of the non-desert portions of the country are threatened by periodic drought and desertification. The economy is concentrated around subsistence, with some export agriculture in the more fertile south, and export of raw materials, especially uranium ore. Niger faces serious challenges to development due to its landlocked position, desert terrain, inefficient agriculture, high fertility rates without birth control, and the resulting overpopulation,[17] the poor educational level and the poverty of its people, the lack of infrastructure, the poor health care, and the environmental degradation.
Nigerien society reflects a diversity drawn from the long independent histories of its several ethnic groups and regions and their relatively short period living in a single state. Historically, what is now Niger has been on the fringes of several large states. Since independence, Nigeriens have lived under five constitutions and three periods of military rule. After the military coup in 2010, Niger became a democratic, multi-party state. A majority of the population lives in rural areas, and have little access to advanced education.
History

Prehistory

Early human settlement in Niger is evidenced by numerous archaeological remains. In prehistoric times, the climate of the Sahara (Ténéré desert in Niger) was wet and provided favorable conditions for agriculture and livestock herding in a fertile grassland environment five thousand years ago.[18]
In 2005–06, a graveyard in the Ténéré desert was discovered by Paul Sereno, a paleontologist from the University of Chicago.[19] His team discovered 5,000-year-old remains of a woman and two children in the Ténéré Desert.[19] The evidence along with remains of animals that do not typically live in desert are among the strongest evidence of the 'green' Sahara in Niger. It is believed that progressive desertification around 5000 BCE pushed sedentary populations to the south and south-east (Lake Chad).[20]

Empires and kingdoms in pre-colonial Niger
By at least the 5th century BCE, Niger had become an area of trans-Saharan trade, led by the Berber tribes from the north, who used camels as a well-adapted means of transportation through the desert. This trade made Agadez a pivotal place of the trans-Saharan trade. This mobility, which would continue in waves for several centuries, was accompanied with further migration to the south and interbreeding between southern black and northern white populations. It was also aided by the introduction of Islam to the region at the end of the 7th century.[20] Several empires and kingdoms also flourished during this era, up to the beginning of colonization in Africa.
Songhai Empire (600–1591)

The Songhai Empire was an empire bearing the name of its main ethnic group, the Songhai or Sonrai, located in western Africa on the bend of the Niger River in present-day Niger, Mali and Burkina Faso. In the 7th century, Songhai tribes settled down north of modern-day Niamey and founded the Songhai city-states of Koukia and Gao. By the 11th century, Gao had become the capital of the Songhai Empire.[21]
From 1000 to 1325, The Songhai Empire prospered and managed to maintain peace with its neighboring empires including the Mali Empire. In 1325 the Songhai Empire was conquered by the Mali Empire but was freed in 1335 by prince Ali Kolen and his brother, Songhai princes held captive by Moussa Kankan, the ruler of the Mali Empire.[21] From the mid-15th to the late 16th century, Songhai was one of the largest Islamic empires in history.[22]

Hausa kingdoms (mid-14th century – 1808)

Between the Niger River and Lake Chad lay Hausa kingdoms and fertile areas. These kingdoms flourished from the mid-14th century up until the early 19th century, when they were conquered by Usman dan Fodio, founder of the Sokoto Empire. The Hausa kingdoms were not a compact entity but several federations of kingdoms more or less independent of one other. Their organization was somewhat democratic: the Hausa kings were elected by the notables of the country and could be removed by them.[21]
The Hausa Kingdoms began as seven states founded according to the Bayajidda legend by the six sons of Bawo. Bawo was the only son of the Hausa queen Daurama and Bayajidda or (Abu Yazid according to certain Nigerien historians) who came from Baghdad. The seven original Hausa states were: Daoura (state of queen Daurama), Kano, Rano, Zaria, Gobir, Katsena and Biram.[21]
Mali Empire

The Mali Empire was a Mandinka empire founded by Sundiata Keita circa 1230 that existed up to 1600. At its peak circa 1350, the empire extended as far west as Senegal and Guinee Conakry and as far east as western Niger.
Kanem-Bornu Empire

The Kanem-Bornu Empire was an empire that existed in modern-day Chad, Nigeria, Cameroon, Niger and Libya. The empire first existed and prospered as the Kanem Empire as early as the 9th century and later as the Kingdom of Bornu until 1900.
French Niger (1900–58)

In the 19th century, contact with Europe began with the first European explorers—notably Monteil (French) and Barth (German)—to travel to Niger.
Following the 1885 Berlin conference during which colonial powers outlined the division of Africa into colonial spheres, French military efforts to conquer existing African states were intensified in all French colonies including Niger. This included several military expeditions including the Voulet Chanoine Mission, which became notorious for pillaging, looting, raping and killing many local civilians on its passage. On 8 May 1899, in retaliation for the resistance of queen Sarraounia, captain Voulet and his men murdered all the inhabitants of the village of Birni-N'Konni in what is regarded as one of the worst massacres in French colonial history. French military expeditions met great resistance from several ethnic groups, especially Hausa and Tuareg groups. The most notable Tuareg revolt was the Kaocen Revolt. The French authorities also abolished the widespread slavery among Tuareg communities.
By 1922, all resistance to colonial rule was eliminated and Niger became a French colony. Niger's colonial history and development parallel that of other French West African territories. France administered her West African colonies through a governor general at Dakar, Senegal, and governors in the individual territories, including Niger. In addition to conferring a limited form of French citizenship on the inhabitants of the territories, the 1946 French constitution provided for decentralization of power and limited participation in political life for local advisory assemblies.
The end of the colonial era was characterized by a transformation of the political environment in French West Africa and Niger. The Nigerien Progressive Party, the Nigerien section of the African Democratic Rally Party, founded in May 1946, united various tendencies of Nigerien people in the movement for national independence. In alliance with progressive French elements and other independence African movements, the movements acquired the suppression of forced labor and arbitrary requisitions as well as legal equality between the African and the French citizens.
Independence (1958)
Following the Overseas Reform Act (Loi Cadre) of 23 July 1956 and the establishment of the Fifth French Republic on 4 December 1958, Niger became an autonomous state within the French Community. On 18 December 1958, the Republic of Niger was officially created with Hamani Diori as the head of the Counsel of Ministers of the Republic of Niger. On 11 July 1960, Niger decided to leave the French Community and acquired full independence on 3 August 1960 with Diori as its first president.

For its first fourteen years as an independent state, Niger was run by a single-party civilian regime under the presidency of Diori. In 1974, a combination of devastating drought and accusations of rampant corruption resulted in a coup d'état that overthrew the Diori regime.
First military regime: The Supreme Military Council and Second Republic 1974–1991
Col. Seyni Kountché and a small military group under the name of Supreme Military Council deposed Diori in April 1974, following a military coup, the first of many in the post-colonial history of Niger. President Kountché ruled the country until his death in 1987.[23]
The first action of the Kountché military government was to address the food crisis which was one of the catalysts of the military coup.[24] While political prisoners of the Diori regime were released after the coup and the country was stabilized, political and individual freedom deteriorated in general during this period. Political parties were banned. Several attempted coups (1975, 1976 and 1983) were thwarted and authors and associates were severely punished.
Despite the restriction in freedom, the country enjoyed improved economic development with the creation of new companies, the construction of major infrastructure (building and new roads, schools, health centers) and minimal corruption in government agencies, which Kountché did not hesitate to punish severely.[25]
This economic development was helped by the uranium boom as well as optimal usage of public funds.
Kountché was succeeded by his Chief of Staff, Col. Ali Saibou, who was confirmed as Chief of the Supreme Military Council on 14 November 1987, four days after Kountché's death. He introduced political reforms and drafted a new constitution, with the creation of a single party. He went on to rule the country as the Chief of the Supreme Military Council.
The 1989 referendum led to the adoption a new constitution and the creation of the Second Republic of Niger. General Saibou became the first president of the Second Republic after winning the presidential election on 10 December 1989. His presidency started during the Second Republic largely following his efforts at the end of the previous military regime with attempts at normalizing the political situation in the country with the release of political prisoners, liberalization of laws and policies.
President Saibou's efforts to control political reforms failed in the face of trade union and student demands to institute a multi-party democratic system. On 9 February 1990, a violently repressed student march led to the death of three students,[26] which led to increased national and international pressure for a National Conference. The Saibou regime acquiesced to these demands by the end of 1990.
National Conference and Third Republic 1991–1997
The National Sovereign Conference of 1991 marked a turning point in the post-independence era of Niger and brought about multi-party democracy. From 29 July to 3 November, a national conference gathered all fringes of society to examine the political, economic and social situation of the country and make recommendations for the future direction of the country. The conference was presided over by Prof. André Salifou and developed a plan for a transitional government. This transitional government was installed in November 1991 to manage the affairs of state until the institutions of the Third Republic were put into place in April 1993.
While the economy deteriorated over the course of the transition, there were certain notable accomplishments, including the successful conduct of a constitutional referendum; the adoption of key legislation such as the electoral and rural codes; and the holding of several free, fair, and non-violent nationwide elections. Freedom of the press flourished, with the appearance of several new independent newspapers.
After the National Sovereign Conference, the transitional government drafted a new constitution that eliminated the previous single-party system of the 1989 Constitution and guaranteed more freedom. The new constitution was adopted by a referendum on 26 December 1992. Following this, presidential elections were held and Mahamane Ousmane became the first president of the Third Republic on 27 March 1993. The presidency of Mahamane Ousmane was characterized by political turbulence, with four government changes and early legislative elections called in 1995.
The parliamentary election forced cohabitation between a rival president and prime minister and ultimately led to governmental paralysis. As part of an initiative started under the National Sovereign Conference the government signed peace accords in April 1995 with Tuareg and Toubou groups that had been in rebellion since 1990. These groups claimed they lacked attention and resources from the central government. The government agreed to absorb some of the former rebels into the military and, with French assistance, to help others return to a productive civilian life.[27]
Second military regime, Fourth Republic, third military regime 1997–1999
The government paralysis and the political tension was used as a motivation for a second military coup. On 27 January 1996, Col. Ibrahim Baré Maïnassara led a military coup that deposed President Ousmane and ended the Third Republic. Col. Maïnassara created the National Salvation Council composed of military officials, which he headed. The Council carried out a six-month transition period during which a new constitution was drafted and adopted on 12 May 1996.
Presidential campaigns were organized in the months that followed. General Maïnassara entered the campaign as an independent candidate and won the election on 8 July 1996. The elections were viewed nationally and internationally as irregular since the electoral commission was replaced during the campaign.
Ibrahim Baré Maïnassara became the first president of the Fourth Republic. His efforts to justify questionable elections failed to convince donors to restore multilateral and bilateral economic assistance; a desperate Maïnassara ignored an international embargo against Libya and sought Libyan funds to aid Niger's economy. In repeated violations of basic civil liberties by the regime, opposition leaders were imprisoned and journalists often arrested, and deported by an unofficial militia composed of police and military.
On 9 April 1999, Maïnassara was assassinated during a military coup led by Maj. Daouda Malam Wanké, who established a transitional National Reconciliation Council to oversee the drafting of a constitution for the Fifth Republic with a French-style semi-presidential system. The new constitution was adopted on 9 August 1999 and was followed by presidential and legislative elections in October and November of the same year. The elections were generally found to be free and fair by international observers. Wanké withdrew himself from government affairs after the new and democratically elected president was sworn in office.
Fifth republic 1999–2009
After winning the election in November 1999, President Tandja Mamadou was sworn in office on 22 December 1999 as the first president of the Fifth Republic. The first mandate of Tandja Mamadou brought about many administrative and economic reforms that had been halted due to the military coups since the Third Republic. In August 2002, serious unrest within military camps occurred in Niamey, Diffa, and Nguigmi, but the government was able to restore order within several days. On 24 July 2004, the first municipal elections in the history of Niger were held to elect local representatives, previously appointed by the government. These elections were followed by presidential elections. President Tandja Mamadou was re-elected for a second term, thus becoming the first president of the republic to win consecutive elections without being deposed by military coups. The legislative and executive configuration remained quite similar to that of the first term of the President: Hama Amadou was reappointed as Prime Minister and Mahamane Ousmane, the head of the CDS party, was re-elected as the President of the National Assembly (parliament) by his peers.
By 2007, the relationship between President Tandja Mamadou and his prime minister had deteriorated, leading to the replacement of the latter in June 2007 by Seyni Oumarou following a successful vote of no confidence at the Assembly. From 2007 to 2008, the Second Tuareg Rebellion took place in northern Niger, worsening economic prospects at a time of political limited progress. The political environment worsened in the following year as President Tandja Mamadou sought out to extend his presidency by modifying the constitution which limited presidential terms in Niger. Proponents of the extended presidency, rallied behind the Tazartche movement, were countered by opponents (anti-Tazartche) composed of opposition party militants and civil society activists.
Sixth republic and fourth military regime 2009–2010
In 2009, President Tandja Mamadou decided to organize a constitutional referendum seeking to extend his presidency claiming to respond to the desire of the people of Niger. Despite opposition from opposition political parties and against the decision of the Constitutional Court which ruled earlier that the referendum would be unconstitutional, President Tandja Mamadou modified and adopted a new constitution by referendum. It was declared illegal by the Constitutional Court but the President dissolved the Court and assumed emergency powers. The opposition boycotted the referendum and the new constitution was adopted with 92.5% of voters and a 68% turnout, according to official results. The adoption of the new constitution created a Sixth Republic, with a presidential system, as well as the suspension of the 1999 Constitution and a three-year interim government with Tandja Mamadou as president. Political and social unrest spiraled before, during and after the referendum project and ultimately led to a military coup in 2010 that ended the brief existence of the 6th Republic.
In a February 2010 coup d'état, a military junta led by captain Salou Djibo was established in response to Tandja's attempted extension of his political term by modifying the constitution. The Supreme Council for the Restoration of Democracy led by General Salou Djibo carried out a one-year transition plan, drafted a new constitution and held elections in 2011 that were judged internationally as free and fair.
Seventh republic 2010–present
Following the adoption of the newest constitution of 2010 and the presidential elections, Mahamadou Issoufou was elected as the first president of the Seventh Republic.
Geography, climate, and ecology

Niger is a landlocked nation in West Africa located along the border between the Sahara and Sub-Saharan regions. It borders Nigeria and Benin to the south, Burkina Faso and Mali to the west, Algeria and Libya to the north and Chad to the east.
Niger lies between latitudes 11° and 24°N, and longitudes 0° and 16°E. Niger's area is 1,267,000 square kilometres (489,191sqmi) of which 300 square kilometres (116sqmi) is water. This makes it slightly less than twice the size of France, and the world's twenty-second largest country.
Niger borders seven countries and has a total perimeter of 5,697 kilometres (3,540mi). The longest border is with Nigeria to the south (1,497km or 930mi). This is followed by Chad to the east, at 1,175km (730mi), Algeria to the north-northwest (956km or 594mi), and Mali at 821km (510mi). Niger also has small borders in its far southwest with Burkina Faso at 628km (390mi) and Benin at 266km (165mi) and to the north-northeast Libya at 354km (220mi).
The lowest point is the Niger River, with an elevation of 200 metres (656ft). The highest point is Mont Idoukal-n-Taghès in the Aïr Mountains at 2,022m (6,634ft).
Climate

Niger's subtropical climate is mainly very hot and very dry, with much desert area. In the extreme south there is a tropical climate on the edges of the Niger River basin. The terrain is predominantly desert plains and sand dunes, with flat to rolling savanna in the south and hills in the north.
Environment

The north of Niger is covered by large deserts and semi deserts. The typical mammal fauna consists of Addax antelopes, Scimitar-horned oryx, gazelles and in mountains Barbary sheep. One of the largest reserves of the world, the Aïr and Ténéré National Nature Reserve, was founded in the northern parts of the Niger to protect these rare species.
The southern parts of Niger are naturally dominated savannahs. The W National Park, situated in the bordering area to Burkina Faso and Benin, belongs to one of the most important areas for wildlife in Western Africa, which is called the WAP (W–Arli–Pendjari) Complex. It has the most important population of the rare West African lion and one of the last populations of the Northwest African cheetah.
Other wildlife includes elephants, buffaloes, roan antelopes, kob antelopes and warthogs. The West African giraffe is currently not found in the W National Park, but further north in Niger, where it has its last relict population.
Environmental issues in Niger include destructive farming practices as a result of population pressure. Illegal hunting, bush fires in some areas and human encroachment upon the flood plains of the Niger River for paddy cultivation are environmental issues. Dams constructed on the Niger River in the neighboring countries of Mali and Guinea and also within Niger itself are also cited as a reason for a reduction of water flow in the Niger River—which has a direct effect upon the environment. A lack of adequate staff to guard wildlife in the parks and reserves is another factor cited for loss of wildlife.[28]
Governance and politics

Niger's new constitution was approved on 31 October 2010. It restored the semi-presidential system of government of the 1999 constitution (Fifth Republic) in which the president of the republic, elected by universal suffrage for a five-year term, and a prime minister named by the president share executive power.
As a reflection of Niger's increasing population, the unicameral National Assembly was expanded in 2004 to 113 deputies elected for a five-year term under a majority system of representation. Political parties must attain at least 5 percent of the vote in order to gain a seat in the legislature.
The constitution also provides for the popular election of municipal and local officials, and the first-ever successful municipal elections took place on 24 July 2004. The National Assembly passed in June 2002 a series of decentralization bills. As a first step, administrative powers will be distributed among 265 communes (local councils); in later stages, regions and departments will be established as decentralized entities. A new electoral code was adopted to reflect the decentralization context. The country is currently divided into 8 regions, which are subdivided into 36 districts (departments). The chief administrator (Governor) in each department is appointed by the government and functions primarily as the local agent of the central authorities.
On 26 May 2009, President Tandja dissolved parliament after the country's constitutional court ruled against plans to hold a referendum on whether to allow him a third term in office. According to the constitution, a new parliament was elected within three months.[29] This began a political struggle between Tandja, trying to extend his term-limited authority beyond 2009 through the establishment of a Sixth Republic, and his opponents who demanded that he step down at the end of his second term in December 2009. See 2009 Nigerien constitutional crisis. The military took over the country and President Tandja was put in prison, charged with corruption.
The military kept their promise to return the country to democratic civilian rule. A constitutional referendum and national elections were held. A presidential election was held on 31 January 2011, but as no clear winner emerged, run-off elections were held on 12 March 2011. Mahamadou Issoufou of the Nigerien Party for Democracy and Socialism was elected president. A parliamentary election was held at the same time.[30][31][32]
Foreign relations

Niger pursues a moderate foreign policy and maintains friendly relations with the West and the Islamic world as well as non-aligned countries. It belongs to the UN and its main specialized agencies and in 1980–81 served on the UN Security Council. Niger maintains a special relationship with former colonial power France and has close relations with its West African neighbors.
It is a charter member of the African Union and the West African Monetary Union and also belongs to the Niger Basin Authority and Lake Chad Basin Commission, the Economic Community of West African States, the Non-Aligned Movement, the Organisation of Islamic Cooperation and the Organization for the Harmonization of Business Law in Africa (OHADA). The westernmost regions of Niger are joined with contiguous regions of Mali and Burkina Faso under the Liptako-Gourma Authority.
The border dispute with Benin, inherited from colonial times and concerning inter alia Lété Island in the Niger River, was solved by the International Court of Justice in 2005 to Niger's advantage.
Government finance
Government finance is derived revenue exports (Mining, oil and agricultural exports) as well as various forms of taxes collected by the government. In the past, foreign aid has contributed to large percentages of the budget. In 2013, Niger's government has adopted a zero-deficit budget of 1.279 trillion CFA francs ($2.53 billion) which is claimed to balance revenues and expenditures by an 11% reduction in the budget from the previous year.[33]
The 2014 budget was 1.867 trillion CFA which is distributed as follows according to: public debt (76,703,692,000 CFA), personnel expenditures (210,979,633,960 CFA), operating expenditures (128,988,777,711 CFA); subsidies and transfers: 308,379,641,366 CFA) and Investment (1,142,513,658,712 CFA).[34]
Foreign aid
The importance of external support for Niger's development is demonstrated by the fact that about 45% of the government's FY 2002 budget, including 80% of its capital budget, derives from donor resources.[35] The most important donors in Niger are France, the European Union, the World Bank, the International Monetary Fund, and various United Nations agencies (UNDP, UNICEF, FAO, World Food Program, and United Nations Population Fund).
Other principal donors include the United States, Belgium, Germany, Switzerland, Canada, and Saudi Arabia. While USAID does not have an office in Niger, the United States is a major donor, contributing nearly $10 million each year to Niger's development. The U.S. also is a major partner in policy coordination in such areas as food security and HIV/AIDS.
Judicial system

The current Judiciary of Niger was established with the creation of the Fourth Republic in 1999. The constitution of December 1992 was revised by national referendum on 12 May 1996 and, again, by referendum, revised to the current version on 18 July 1999. It is based on the Code Napoleon "Inquisitorial system", established in Niger during French colonial rule and the 1960 Constitution of Niger. The Court of Appeals reviews questions of fact and law, while the Supreme Court reviews application of the law and constitutional questions. The High Court of Justice (HCJ) deals with cases involving senior government officials. The justice system also includes civil criminal courts, customary courts, traditional mediation, and a military court.[36] The military court provides the same rights as civil criminal courts; however, customary courts do not. The military court cannot try civilians.[37]
Law enforcement

Law enforcement in Niger is the responsibility of the Ministry of Defense through the National Gendarmerie and the Ministry of the Interior through the National Police and the National Guard. The National Police is primarily responsible for law enforcement in urban areas. Outside big cities and in rural areas, this responsibility falls on the National Gendarmerie and the National Guard.
Military

The Niger Armed Forces (Forces armées nigériennes) are the military and paramilitary forces of Niger, under the president as supreme commander. They consist of the Niger Army (Armée de Terre), the Niger Air Force (Armée de l'Air) and the auxiliary paramilitary forces, such as the National Gendarmerie (Gendarmerie nationale) and the National Guard (Garde Nationale). Both paramilitary forces are trained in military fashion and have some military responsibilities in wartime. In peace time their duties are mostly policing duties.
The armed forces are composed of approximately 12,900 personnel, including 3,700 gendarmes, 3200 national guards, 300 air force personnel, and 6,000 army personnel. The armed forces of Niger have been involved several military coups over the years with the most recent in 2010. Niger's armed forces have a long history of military cooperation with France and the United States. As of 2013, Niamey is home to a U.S. drone base.
Administrative divisions

Niger is divided into 7 Regions and one capital district. These Regions are subdivided into 36 departments. The 36 Departments are currently broken down into Communes of varying types. As of 2006 there were 265 communes, including communes urbaines (Urban Communes: as subdivisions of major cities), communes rurales (Rural Communes), in sparsely populated areas and postes administratifs (Administrative Posts) for largely uninhabited desert areas or military zones.
Rural communes may contain official villages and settlements, while Urban Communes are divided into quarters. Niger subvisions were renamed in 2002, in the implementation of a decentralisation project, first begun in 1998. Previously, Niger was divided into 7 Departments, 36 Arrondissements, and Communes. These subdivisions were administered by officials appointed by the national government. These offices will be replaced in the future by democratically elected councils at each level.
The pre-2002 departments (renamed as regions) and capital district are:
Agadez Region
Diffa Region
Dosso Region
Maradi Region
Tahoua Region
Tillabéri Region
Zinder Region
Niamey (capital district)
Largest cities and towns

vt Largest cities or towns in Niger
According to the 2012 Census[38]RankNameRegionPop.
Niamey

Maradi1NiameyNiamey978,029
Zinder

Tahoua2MaradiMaradi267,2493ZinderZinder235,6054TahouaTahoua117,8265AgadezAgadez110,4976ArlitAgadez78,6517Birni-N'KonniTahoua63,1698DossoDosso58,6719GayaDosso45,46510TessaouaMaradi43,409
Economy

The economy of Niger centers on subsistence crops, livestock, and some of the world's largest uranium deposits. Drought cycles, desertification, a 2.9% population growth rate, and the drop in world demand for uranium have undercut the economy.
Niger shares a common currency, the CFA franc, and a common central bank, the Central Bank of West African States (BCEAO), with seven other members of the West African Monetary Union. Niger is also a member of the Organization for the Harmonization of Business Law in Africa (OHADA).[39]
In December 2000, Niger qualified for enhanced debt relief under the International Monetary Fund program for Heavily Indebted Poor Countries (HIPC) and concluded an agreement with the Fund for Poverty Reduction and Growth Facility (PRGF). Debt relief provided under the enhanced HIPC initiative significantly reduces Niger's annual debt service obligations, freeing funds for expenditures on basic health care, primary education, HIV/AIDS prevention, rural infrastructure, and other programs geared at poverty reduction.
In December 2005, it was announced that Niger had received 100% multilateral debt relief from the IMF, which translates into the forgiveness of approximately US$86million in debts to the IMF, excluding the remaining assistance under HIPC. Nearly half of the government's budget is derived from foreign donor resources. Future growth may be sustained by exploitation of oil, gold, coal, and other mineral resources. Uranium prices have recovered somewhat in the last few years. A drought and locust infestation in 2005 led to food shortages for as many as 2.5million Nigeriens.
Society
Demographics

As of 2016, the population of Niger was 20,672,987[15]. Expanding from a population of 1.7 million in 1960, Niger's population has rapidly increased with a current growth rate of 3.3% (7.1 children per mother[40]).[41]
This growth rate is one of the highest in the world and is a source of concern for the government and international agencies.[40] The population is predominantly young, with 49.2% under 15 years old and 2.7% over 65 years, and predominantly rural with only 21% living in urban areas.[41]
A 2005 study stated that over 800,000 people (nearly 8 per cent of the population) in Niger are enslaved.[42][43][44]
Ethnic groups

Niger has a wide variety of ethnic groups as in most West African countries. The ethnic makeup of Niger is as follows: Hausa (53.0%), Zarma-Songhai (21.2%), Tuareg (10.4%), Fula (French: Peuls; Fula: Fulɓe) (9.9%), Kanuri Manga (4.4%), Tubu (0.4%), Arab (0.3%), Gourmantche (0.3%), other (0.2%).[41]
Languages

French, inherited from the colonial period, is the official language. It is spoken mainly as a second language by people who have received a formal western education and serves as the administrative language. Niger has been a member of the Organisation Internationale de la Francophonie since 1970.
Niger has ten official national languages, namely Arabic, Buduma, Fulfulde, Gourmanchéma, Hausa, Kanuri, Zarma & Songhai, Tamasheq, Tassawaq, Tebu.[1] Each is spoken as a first language primarily by the ethnic group with which it is associated.[45][46] Hausa and Zarma-Sonrai, the two most spoken languages, are widely spoken throughout the country as first or second languages.
Largest cities

Religion

Niger is a secular country and separation of state and religion is guaranteed by Articles 3 and 175 of the 2010 Constitution, which dictate that future amendments or revisions may not modify the secular nature of the republic of Niger. Religious freedom is protected by Article 30 of the same constitution. Islam, widespread in the region since the 10th century, has greatly shaped the culture and mores of the people of Niger. Islam is the most dominant religion, practiced by 99% of the population according to the 2012 census.[49]
The other two main religions of Niger are Christianity, practiced by 0.3% of the population, and Animism (traditional indigenous religious beliefs), practiced by 0.2% of the population.[49] Christianity was established earlier in the country by missionaries during the French colonial years. Other urban Christian expatriate communities from Europe and West Africa are also presented. Religious persecution is rare in Niger which is ranked last (#50) on the World Watch List for severity of persecution that Christians face for actively pursuing their faith.
The numbers of Animist practitioners are a point of contention. As recently as the late 19th century, much of the south center of the nation was unreached by Islam, and the conversion of some rural areas has been only partial. There are still areas where animist based festivals and traditions (such as the Bori religion) are practiced by syncretic Muslim communities (in some Hausa areas as well as among some Toubou and Wodaabe pastoralists), as opposed to several small communities who maintain their pre-Islamic religion. These include the Hausa-speaking Maouri (or Azna, the Hausa word for "pagan") community in Dogondoutci in the south-southwest and the Kanuri speaking Manga near Zinder, both of whom practice variations of the pre-Islamic Hausa Maguzawa religion. There are also some tiny Boudouma and Songhay animist communities in the southwest.[50]
Islam

The majority of Muslims in Niger are Sunni, 7% are Shi'a, 5% are Ahmadiyya and 20% non-denominational.[51][52] Islam was spread into what is now Niger beginning in the 15th century, by both the expansion of the Songhai Empire in the west, and the influence of the Trans-Saharan trade traveling from the Maghreb and Egypt. Tuareg expansion from the north, culminating in their seizure of the far eastern oases from the Kanem-Bornu Empire in the 17th centuries, spread distinctively Berber practices.
Both Zarma and Hausa areas were greatly influenced by the 18th- and 19th-century Fula led Sufi brotherhoods, most notably the Sokoto Caliphate (in today's Nigeria). Modern Muslim practice in Niger is often tied to the Tijaniya Sufi brotherhoods, although there are small minority groups tied to Hammallism and Nyassist Sufi orders in the west, and the Sanusiya in the far northeast.[50]
A small center of followers of Salafi movement within Sunni Islam have appeared in the last thirty years, in the capital and in Maradi.[53] These small groups, linked to similar groups in Jos, Nigeria, came to public prominence in the 1990s during a series of religious riots.[54][55][56]
Despite this, Niger maintains a tradition as a secular state, protected by law.[57] Interfaith relations are deemed very good, and the forms of Islam traditionally practiced in most of the country are marked by tolerance of other faiths and lack of restrictions on personal freedom.[58] Divorce and polygyny are unremarkable, women are not secluded, and head coverings are not mandatory—they are often a rarity in urban areas.[59] Alcohol, such as the locally produced Bière Niger, is sold openly in most of the country.
Education

The literacy rate of Niger is among the lowest in the world; in 2005 it was estimated to be only 28.7% (42.9% male and 15.1% female).[60] Primary education in Niger is compulsory for six years.[61] The primary school enrollment and attendance rates are low, particularly for girls.[61] In 1997, the gross primary enrollment rate was 29.3 percent, and in 1996, the net primary enrollment rate was 24.5 percent.[61]
About 60 percent of children who finish primary schools are boys, as the majority of girls rarely attend school for more than a few years.[61] Children are often forced to work rather than attend school, particularly during planting or harvest periods.[61] Nomadic children in the north of the country often do not have access to schools.[61]
Health

The child mortality rate in Niger (deaths among children between the ages of 1 and 4) is high (248 per 1,000) due to generally poor health conditions and inadequate nutrition for most of the country's children. According to the organization Save the Children, Niger has the world's highest infant mortality rate.[62]
Niger also has the highest fertility rate in the world (6.49 births per woman according to 2017 estimates[63]); this means that nearly half (49%) of the Nigerien population is under age 15. Niger has the 11th highest maternal mortality rate in the world at 820 deaths/100,000 live births.[64] There were 3 physicians and 22 nurses per 100,000 persons in 2006.[65]
Culture

Nigerien culture is marked by variation, evidence of the cultural crossroads which French colonialism formed into a unified state from the beginning of the 20th century. What is now Niger was created from four distinct cultural areas in the pre-colonial era: the Zarma dominated Niger River valley in the southwest; the northern periphery of Hausaland, made mostly of those states which had resisted the Sokoto Caliphate, and ranged along the long southern border with Nigeria; the Lake Chad basin and Kaouar in the far east, populated by Kanuri farmers and Toubou pastoralists who had once been part of the Kanem-Bornu Empire; and the Tuareg nomads of the Aïr Mountains and Saharan desert in the vast north.
Each of these communities, along with smaller ethnic groups like the pastoral Wodaabe Fula, brought their own cultural traditions to the new state of Niger. While successive post-independence governments have tried to forge a shared national culture, this has been slow forming, in part because the major Nigerien communities have their own cultural histories, and in part because Nigerien ethnic groups such as the Hausa, Tuareg and Kanuri are but part of larger ethnic communities which cross borders introduced under colonialism.
Until the 1990s, government and politics was inordinately dominated by Niamey and the Zarma people of the surrounding region. At the same time the plurality of the population, in the Hausa borderlands between Birni-N'Konni and Maine-Soroa, have often looked culturally more to Hausaland in Nigeria than Niamey. Between 1996 and 2003, primary school attendance was around 30%,[66] including 36% of males and only 25% of females. Additional education occurs through madrasas.
Festivals and cultural events
Guérewol festival

The Guérewol festival is a traditional Wodaabe cultural event that takes place in Abalak in Tahoua region or In'Gall in Agadez Region. It is an annual traditional courtship ritual practiced by the Wodaabe (Fula) people of Niger. During this ceremony, young men dressed in elaborate ornamentation and made up in traditional face painting gather in lines to dance and sing, vying for the attention of marriageable young women. The Guérewol festival is an internationally attraction and was featured in films and magazines as prominent as the National Geographic.
Cure Salée festival

"La Cure salée" (English: Salt Cure) is a yearly festival of Tuareg and Wodaabe nomads in In'Gall in Agadez Region traditionally to celebrate the end of the rainy season. For three days, the festival features a parade of Tuareg camel riders followed with camel and horse races, songs, dances, and storytelling.
Media

Niger began developing diverse media in the late 1990s. Prior to the Third Republic, Nigeriens only had access to tightly controlled state media.[67] Now Niamey contains scores of newspapers and magazines; some, like Le Sahel, are government operated, while many are critical of the government.[68][69] Radio is the most important medium, as television sets are beyond the buying power of many of the rural poor, and illiteracy prevents print media from becoming a mass medium.[28]
In addition to the national and regional radio services of the state broadcaster ORTN, there are four privately owned radio networks which total more than 100 stations. Three of them—the Anfani Group, Sarounia and Tenere—are urban-based commercial-format FM networks in the major towns.[70] There is also a network of over 80 community radio stations spread across all seven regions of the country, governed by the Comité de Pilotage de Radios de Proximité (CPRP), a civil society organisation. The independent-sector radio networks are collectively estimated by CPRP officials to cover some 7.6million people, or about 73% of the population (2005).
Aside from Nigerien radio stations, the BBC's Hausa service is listened to on FM repeaters across wide parts of the country, particularly in the south, close to the border with Nigeria. Radio France Internationale also rebroadcasts in French through some of the commercial stations, via satellite. Tenere FM also runs a national independent television station of the same name.[70]
Despite relative freedom at the national level, Nigerien journalists say they are often pressured by local authorities.[71] The state ORTN network depends financially on the government, partly through a surcharge on electricity bills, and partly through direct subsidy. The sector is governed by the Conseil Supérieur de Communications, established as an independent body in the early 1990s, since 2007 headed by Daouda Diallo. International human rights groups have criticised the government since at least 1996 as using regulation and police to punish criticism of the state.[72][73]
See also

Outline of Niger

Sources

Decalo, Samuel. Historical Dictionary of Niger, 3rd ed. (Scarecrow Press, 1997, ISBN0-8108-3136-8)– a comprehensive collection of Niger topics
CIA World Factbook ()
US State Department  Note: This article contains material from the State Department website.

 from UCB Libraries GovPubs
 at Curlie
 from the BBC News
Wikimedia Atlas of Niger
Main Page travel guide from Wikivoyage
 from International Futures
Trade


Neurodegeneration is the progressive loss of structure or function of neurons, including death of neurons. Many neurodegenerative diseases – including amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, and Huntington's disease – occur as a result of neurodegenerative processes. Such diseases are incurable, resulting in progressive degeneration and/or death of neuron cells.[1] As research progresses, many similarities appear that relate these diseases to one another on a sub-cellular level. Discovering these similarities offers hope for therapeutic advances that could ameliorate many diseases simultaneously. There are many parallels between different neurodegenerative disorders including atypical protein assemblies as well as induced cell death.[2][3] Neurodegeneration can be found in many different levels of neuronal circuitry ranging from molecular to systemic.
Risk factor
The greatest risk factor for neurodegenerative diseases is aging. Mitochondrial DNA mutations as well as oxidative stress both contribute to aging.[4] Many of these diseases are late-onset, meaning there is some factor that changes as a person ages for each disease.[2] One constant factor is that in each disease, neurons gradually lose function as the disease progresses with age. It has been proposed that DNA damage accumulation provides the underlying causative link between aging and neurodegenerative disease.[5][6]
Mechanisms
Genetics

Many neurodegenerative diseases are caused by genetic mutations, most of which are located in completely unrelated genes. In many of the different diseases, the mutated gene has a common feature: a repeat of the CAG nucleotide triplet. CAG encodes for the amino acid glutamine. A repeat of CAG results in a polyglutamine (polyQ) tract. Diseases showing this are known as polyglutamine diseases.[7][8]
Polyglutamine: A repeat in this causes dominant pathogenesis. Extra glutamine residues can acquire toxic properties through a variety of ways, including irregular protein folding and degradation pathways, altered subcellular localization, and abnormal interactions with other cellular proteins.[7] PolyQ studies often use a variety of animal models because there is such a clearly defined trigger – repeat expansion. Extensive research has been done using the models of nematode (C. elegans), and fruit fly (Drosophila), mice, and non-human primates. Mammalian data is often needed for FDA approval of drugs, which means that the bulk of the research is done using mice. Using data from the other animals (C. elegans and Drosophila primarily) is often a precursor to finding the equivalent mammalian gene.[8][9]
Nine inherited neurodegenerative diseases are caused by the expansion of the CAG trinucleotide and polyQ tract.[10] Two examples are Huntington's disease and the spinocerebellar ataxias. For a complete list, see the table under Polyglutamine (PolyQ) Diseases in the article Trinucleotide repeat disorder. While polyglutamine-repeat diseases encompass many different neurodegenerative disorders, there are many more it does not apply to. The genetics behind each disease are different and often unknown.
Protein misfolding
Several neurodegenerative diseases are classified as proteopathies as they are associated with the aggregation of misfolded proteins.
alpha-synuclein: can aggregate to form insoluble fibrils in pathological conditions characterized by Lewy bodies, such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Alpha-synuclein is the primary structural component of Lewy body fibrils. In addition, an alpha-synuclein fragment, known as the non-Abeta component (NAC), is found in amyloid plaques in Alzheimer's disease.
tau: hyperphosphorylated tau protein is the main component of neurofibrillary tangles in Alzheimer's disease.
beta amyloid: the major component of senile plaques in Alzheimer's disease.
prion: main component of prion diseases and transmissible spongiform encephalopathies.
Intracellular mechanisms
Protein degradation pathways
Parkinson's disease and Huntington's disease are both late-onset and associated with the accumulation of intracellular toxic proteins. Diseases caused by the aggregation of proteins are known as proteinopathies, and they are primarily caused by aggregates in the following structures:[2]
cytosol, e.g. Parkinson's & Huntington's
nucleus, e.g. Spinocerebellar ataxia type 1 (SCA1)
endoplasmic reticulum (ER), (as seen with neuroserpin mutations that cause familial encephalopathy with neuroserpin inclusion bodies)
extracellularly excreted proteins, amyloid-β in Alzheimer's disease
There are two main avenues eukaryotic cells use to remove troublesome proteins or organelles:
ubiquitin–proteasome: protein ubiquitin along with enzymes is key for the degradation of many proteins that cause proteinopathies including polyQ expansions and alpha-synucleins. Research indicates proteasome enzymes may not be able to correctly cleave these irregular proteins, which could possibly result in a more toxic species. This is the primary route cells use to degrade proteins.[2]
Decreased proteasome activity is consistent with models in which intracellular protein aggregates form. It is still unknown whether or not these aggregates are a cause or a result of neurodegeneration.[2]
autophagy–lysosome pathways: a form of programmed cell death (PCD), this becomes the favorable route when a protein is aggregate-prone meaning it is a poor proteasome substrate. This can be split into two forms of autophagy: macroautophagy and chaperone-mediated autophagy (CMA).[2]
macroautophagy is involved with nutrient recycling of macromolecules under conditions of starvation, certain apoptotic pathways, and if absent, leads to the formation of ubiquinated inclusions. Experiments in mice with neuronally confined macroautophagy-gene knockouts develop intraneuronal aggregates leading to neurodegeneration.[2]
chaperone-mediated autophagy defects may also lead to neurodegeneration. Research has shown that mutant proteins bind to the CMA-pathway receptors on lysosomal membrane and in doing so block their own degradation as well as the degradation of other substrates.[2]
Membrane damage
Damage to the membranes of organelles by monomeric or oligomeric proteins could also contribute to these diseases. Alpha-synuclein can damage membranes by inducing membrane curvature,[11] and cause extensive tubulation and vesiculation when incubated with artificial phospholipid vesicles.[11]

Mitochondrial dysfunction
The most common form of cell death in neurodegeneration is through the intrinsic mitochondrial apoptotic pathway. This pathway controls the activation of caspase-9 by regulating the release of cytochrome c from the mitochondrial intermembrane space (IMS). Reactive oxygen species (ROS) are normal byproducts of mitochondrial respiratory chain activity. ROS concentration is mediated by mitochondrial antioxidants such as manganese superoxide dismutase (SOD2) and glutathione peroxidase. Over production of ROS (oxidative stress) is a central feature of all neurodegenerative disorders. In addition to the generation of ROS, mitochondria are also involved with life-sustaining functions including calcium homeostasis, PCD, mitochondrial fission and fusion, lipid concentration of the mitochondrial membranes, and the mitochondrial permeability transition. Mitochondrial disease leading to neurodegeneration is likely, at least on some level, to involve all of these functions.[12]
There is strong evidence that mitochondrial dysfunction and oxidative stress play a causal role in neurodegenerative disease pathogenesis, including in four of the more well known diseases Alzheimer's, Parkinson's, Huntington's, and Amyotrophic lateral sclerosis.[4]
Neurons are particularly vulnerable to oxidative damage due to their strong metabolic activity associated with high transcription levels, high oxygen consumption, and weak antioxidant defense.[13][14]
DNA Damage
The brain metabolizes as much as a fifth of consumed oxygen, and reactive oxygen species produced by oxidative metabolism are a major source of DNA damage in the brain.  Damage to a cell’s DNA is particularly harmful because DNA is the blueprint for protein production and unlike other molecules it cannot simply be replaced by re-synthesis. The vulnerability of post-mitotic neurons to DNA damage (such as oxidative lesions or certain types of DNA strand breaks), coupled with a gradual decline in the activities of repair mechanisms, could lead to accumulation of DNA damage with age and contribute to brain aging and neurodegeneration.[15] DNA single-strand breaks are common and are associated with the neurodegenerative disease ataxia-oculomotor apraxia.[16][14]  Increased oxidative DNA damage in the brain is associated with Alzheimer’s disease and Parkinson’s disease.[16]  Defective DNA repair has been linked to neurodegenerative disorders such as Alzheimer’s disease, amyotrophic lateral sclerosis, ataxia telangiectasia, Cockayne syndrome, Parkinson’s disease and xeroderma pigmentosum.[16][15]
Axonal transport
Axonal swelling and spheroids have been observed in many different neurodegenerative diseases. This suggests that defective axons are not only present in diseased neurons, but also that they may cause certain pathological insult due to accumulation of organelles. Axonal transport can be disrupted by a variety of mechanisms including damage to: kinesin and cytoplasmic dynein, microtubules, cargoes, and mitochondria.[17] When axonal transport is severely disrupted a degenerative pathway known as Wallerian-like degeneration is often triggered.[18]
Programmed cell death
Programmed cell death (PCD) is death of a cell in any form, mediated by an intracellular program.[19] This process can be activated in neurodegenerative diseases including Parkinson's disease, amytrophic lateral sclerosis, Alzheimer's disease and Huntington's disease.[20] There are, however, situations in which these mediated pathways are artificially stimulated due to injury or disease.[3]
Apoptosis (type I)
Apoptosis is a form of programmed cell death in multicellular organisms. It is one of the main types of programmed cell death (PCD) and involves a series of biochemical events leading to a characteristic cell morphology and death.
Extrinsic apoptotic pathways: Occur when factors outside the cell activate cell surface death receptors (e.g., Fas) that result in the activation of caspases-8 or -10.[3]
Intrinsic apoptotic pathways: Result from mitochondrial release of cytochrome c or endoplasmic reticulum malfunctions, each leading to the activation of caspase-9. The nucleus and Golgi apparatus are other organelles that have damage sensors, which can lead the cells down apoptotic pathways.[3][21]
Caspases (cysteine-aspartic acid proteases) cleave at very specific amino acid residues. There are two types of caspases: initiators and effectors. Initiator caspases cleave inactive forms of effector caspases. This activates the effectors that in turn cleave other proteins resulting in apoptotic initiation.[3]
Autophagic (type II)
Autophagy is essentially a form of intracellular phagocytosis in which a cell actively consumes damaged organelles or misfolded proteins by encapsulating them into an autophagosome, which fuses with a lysosome to destroy the contents of the autophagosome. Many neurodegenerative diseases show unusual protein aggregates. This could potentially be a result of underlying autophagic defect common to multiple neurodegenerative diseases. It is important to note that this is a hypothesis, and more research must be done.[3]
Cytoplasmic (type III)
The final and least understood PCD mechanism is through non-apoptotic processes. These fall under Type III, or cytoplasmic cell death. Many other forms of PCD are observed but not fully understood or accepted by the scientific community. For example, PCD might be caused by trophotoxicity, or hyperactivation of trophic factor receptors. In addition to this, other cytotoxins that induce PCD at low concentrations act to cause necrosis, or aponecrosis – the combination of apoptosis and necrosis, when in higher concentrations. It is still unclear exactly what combination of apoptosis, non-apoptosis, and necrosis causes different kinds of aponecrosis.[3]
PCD
In the above-mentioned neurodegenerative diseases, PCD may be pathogenic. In order to identify the potential of neuroprotective targets in PCD machinery, there were experimental models conducted on these neurodegenerative diseases. These studies showed that the expression of certain components have been altered by genetic and pharmacological means. Expression of PCD molecular components are said to be controlled by gene and antisense therapy, but this needs further research. Pharmacological approaches involve inhibitors of caspase activity, and caspase inhibition might delay cell death in the different experimental models.[20]
Transglutaminase
Transglutaminases are human enzymes ubiquitously present in the human body and in the brain in particular.[22]
The main function of transglutaminases is bind proteins and peptides intra- and intermolecularly, by a type of covalent bonds termed isopeptide bonds, in a reaction termed transamidation or crosslinking.[22]
Transglutaminase binding of these proteins and peptides make them clump together. The resulting structures are turned extremely resistant to chemical and mechanical disruption.[22]
Most relevant human neurodegenerative diseases share the property of having abnormal structures made up of proteins and peptides.[22]
Each of these neurodegenerative disesases have one (or several) specific main protein or peptide. In Alzheimer's disease, these are amyloid-beta and tau. In Parkinson’s disease, it is alpha-synuclein. In Huntington’s disease, it is huntingtin.[22]
Transglutaminase substrates:
Amyloid-beta, tau, alpha-synuclein and huntingtin have been proved to be substrates of transglutaminases in vitro or in vivo, that is, they can be bonded by trasglutaminases by covalent bonds to each other and potentially to any other transglutaminase substrate in the brain.[22]
Transglutaminase augmented expression:
It has been proved that in these neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease) the expression of the transglutaminase enzyme is increased.[22]
Presence of isopeptide bonds in these structures:
The presence of isopeptide bonds (the result of the transglutaminase reaction) have been detected in the abnormal structures that are characteristic of these neurodegenerative diseases.[22]
Co-localization:
Co-localization of transglutaminase mediated isopeptide bonds with these abnormal structures has been detected in the autopsy of brains of patients with these diseases.[22]
Specific disorders
Alzheimer's disease

Alzheimer's disease is characterised by loss of neurons and synapses in the cerebral cortex and certain subcortical regions. This loss results in gross atrophy of the affected regions, including degeneration in the temporal lobe and parietal lobe, and parts of the frontal cortex and cingulate gyrus.[23]
Alzheimer's disease has been hypothesized to be a protein misfolding disease (proteopathy), caused by accumulation of abnormally folded A-beta and tau proteins in the brain.[24] Plaques are made up of small peptides, 39–43amino acids in length, called beta-amyloid (also written as A-beta or Aβ). Beta-amyloid is a fragment from a larger protein called amyloid precursor protein (APP), a transmembrane protein that penetrates through the neuron's membrane. APP is critical to neuron growth, survival and post-injury repair.[25][26] In Alzheimer's disease, an unknown process causes APP to be divided into smaller fragments by enzymes through proteolysis.[27] One of these fragments gives rise to fibrils of beta-amyloid, which form clumps that deposit outside neurons in dense formations known as senile plaques.[28][29]
Parkinson's disease

Parkinson's disease is the second most common neurodegenerative disorder[30] and manifests as bradykinesia, rigidity, resting tremor and posture instability. The crude prevalence rate of PD has been reported to range from 15 per 100,000 to 12,500 per 100,000, and the incidence of PD from 15 per 100,000 to 328 per 100,000, with the disease being less common in Asian countries. Parkinson's disease is a degenerative disorder of the central nervous system. It results from the death of dopamine-generating cells in the substantia nigra, a region of the midbrain; the cause of cell-death is unknown. The following paragraph is an excerpt from the Pathophysiology section of the article Parkinson's disease.
The mechanism by which the brain cells in Parkinson's are lost may consist of an abnormal accumulation of the protein alpha-synuclein bound to ubiquitin in the damaged cells. The alpha-synuclein-ubiquitin complex cannot be directed to the proteasome.  This protein accumulation forms proteinaceous cytoplasmic inclusions called Lewy bodies. The latest research on pathogenesis of disease has shown that the death of dopaminergic neurons by alpha-synuclein is due to a defect in the machinery that transports proteins between two major cellular organelles – the endoplasmic reticulum (ER) and the Golgi apparatus. Certain proteins like Rab1 may reverse this defect caused by alpha-synuclein in animal models.[31]
Recent research suggests that impaired axonal transport of alpha-synuclein leads to its accumulation in the Lewy bodies. Experiments have revealed reduced transport rates of both wild-type and two familial Parkinson's disease-associated mutant alpha-synucleins through axons of cultured neurons.[17] Membrane damage by alpha-synuclein could be another Parkinson's disease mechanism.[11]
The main known risk factor is age. Susceptibility genes including α-synuclein, leucine-rich repeat kinase 2 (LRRK-2), and glucocerebrosidase (GBA) have shown that genetic predisposition is another important causal factor.
Huntington's disease

The following paragraph is an excerpt from the Mechanism section of the article Huntington's disease.
HD causes astrogliosis[32] and loss of medium spiny neurons.[33][34] Areas of the brain are affected according to their structure and the types of neurons they contain, reducing in size as they cumulatively lose cells. The areas affected are mainly in the striatum, but also the frontal and temporal cortices.[35] The striatum's subthalamic nuclei send control signals to the globus pallidus, which initiates and modulates motion. The weaker signals from subthalamic nuclei thus cause reduced initiation and modulation of movement, resulting in the characteristic movements of the disorder, notably chorea.[36]
Mutant Huntingtin is an aggregate-prone protein. During the cells' natural clearance process, these proteins are retrogradely transported to the cell body for destruction by lysosomes. It is a possibility that these mutant protein aggregates damage the retrograde transport of important cargoes such as BDNF by damaging molecular motors as well as microtubules.[17]
Amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) is a disease in which motor neurons are selectively targeted for degeneration. In 1993, missense mutations in the gene encoding the antioxidant enzyme Cu/Zn superoxide dismutase 1 (SOD1) were discovered in subsets of patients with familial ALS. This discovery led researchers to focus on unlocking the mechanisms for SOD1-mediated diseases. However, the pathogenic mechanism underlying SOD1 mutant toxicity has yet to be resolved.  More recently, TDP-43 and FUS protein aggregates have been implicated in some cases of the disease, and a mutation in chromosome 9 (C9orf72) is thought to be the most common known cause of sporadic ALS.
Recent independent research by Nagai et al.[37] and Di Giorgio et al.[38] provide in vitro evidence that the primary cellular sites where SOD1 mutations act are located on astrocytes. Astrocytes then cause the toxic effects on the motor neurons. The specific mechanism of toxicity still needs to be investigated, but the findings are significant because they implicate cells other than neuron cells in neurodegeneration.[39]
Batten disease
Batten disease is a rare and fatal recessive neurodegenerative disorder that begins at birth.
Therapeutics
The process of neurodegeneration is not well understood, so the diseases that stem from it have, as yet, no cures. In the search for effective treatments (as opposed to palliative care), investigators employ animal models of disease to test potential therapeutic agents. Model organisms provide an inexpensive and relatively quick means to perform two main functions: target identification and target validation. Together, these help show the value of any specific therapeutic strategies and drugs when attempting to ameliorate disease severity. An example is the drug Dimebon (Medivation). This drug is in phase III clinical trials for use in Alzheimer's disease, and also recently finished phase II clinical trials for use in Huntington's disease.[8] In March 2010, the results of a clinical trial phase III were released; the investigational Alzheimer's disease drug Dimebon failed in the pivotal CONNECTION trial of patients with mild-to-moderate disease.[40] With CONCERT, the remaining Pfizer and Medivation Phase III trial for Dimebon (latrepirdine) in Alzheimer's disease failed in 2012, effectively ending the development in this indication.[41]
In another experiment using a rat model of Alzheimer's disease, it was demonstrated that systemic administration of hypothalamic proline-rich peptide (PRP)-1 offers neuroprotective effects and can prevent neurodegeneration in hippocampus amyloid-beta 25–35. This suggests that there could be therapeutic value to PRP-1.[42]
Protein degradation offers therapeutic options both in preventing the synthesis and degradation of irregular proteins. There is also interest in upregulating autophagy to help clear protein aggregates implicated in neurodegeneration. Both of these options involve very complex pathways that we are only beginning to understand.[2]
The goal of immunotherapy is to enhance aspects of the immune system. Both active and passive vaccinations  have been proposed for Alzheimer's disease and other conditions; however, more research must be done to prove safety and efficacy in humans.[43]
See also
Amyloids
Dementia
JUNQ and IPOD
Nervous system
Prevention of dementia
Proteopathy
Trinucleotide repeat disorders

What is the most common neurodegenerative disease?


The Persian Gulf (Persian: خلیج فارس, romanized:Xalij-e Fârs, lit.'Gulf of Fars'), is a mediterranean sea in Western Asia. The body of water is an extension of the Indian Ocean (Gulf of Oman) through the Strait of Hormuz and lies between Iran to the northeast and the Arabian Peninsula to the southwest.[1] The Shatt al-Arab river delta forms the northwest shoreline.
The Persian Gulf was a battlefield of the 1980–1988 Iran–Iraq War, in which each side attacked the other's oil tankers. It is the namesake of the 1991 Gulf War, the largely air- and land-based conflict that followed Iraq's invasion of Kuwait.
The gulf has many fishing grounds, extensive reefs (mostly rocky, but also coral), and abundant pearl oysters, but its ecology has been damaged by industrialization and oil spills.
The body of water is historically and internationally known as the "Persian Gulf".[2][3][4] Some Arab governments refer to it as the "Arabian Gulf" (Arabic: الخليج العربي, romanized:Al-Khalīj al-ˁArabī) or "The Gulf",[5] but neither term is recognized internationally. The name "Gulf of Iran (Persian Gulf)" is used by the International Hydrographic Organization.[6]
The Persian Gulf resides in the Persian Gulf Basin, which is of Cenozoic origin and related to the subduction of the Arabian Plate under the Zagros Mountains.[7] The current flooding of the basin started 15,000 years ago due to rising sea levels of the Holocene glacial retreat.[8]
Geography

This inland sea of some 251,000 square kilometres (96,912sqmi) is connected to the Gulf of Oman in the east by the Strait of Hormuz; and its western end is marked by the major river delta of the Shatt al-Arab, which carries the waters of the Euphrates and the Tigris. In Iran this is called "Arvand Rood", where "Rood" means "river". Its length is 989 kilometres (615 miles), with Iran covering most of the northern coast and Saudi Arabia most of the southern coast. The Persian Gulf is about 56km (35mi) wide at its narrowest, in the Strait of Hormuz. The waters are overall very shallow, with a maximum depth of 90 metres (295 feet) and an average depth of 50 metres (164 feet).
Countries with a coastline on the Persian Gulf are (clockwise, from the north): Iran; Oman's Musandam exclave; the United Arab Emirates; Saudi Arabia Qatar, on a peninsula off the Saudi coast; Bahrain, on an island; Kuwait; and Iraq in the northwest. Various small islands also lie within the Persian Gulf, some of which are the subject of territorial disputes between the states of the region.
Extent
The International Hydrographic Organization defines the Persian Gulf's southern limit as "The Northwestern limit of Gulf of Oman". This limit is defined as "A line joining Ràs Limah (25°57'N) on the coast of Arabia and Ràs al Kuh (25°48'N) on the coast of Iran (Persia)".[6]
Oceanography
The gulf is connected to Indian Ocean through Strait of Hormuz. Writing the water balance budget for the Persian Gulf, the inputs are river discharges from Iran and Iraq (estimated to be 2000 cubic meters per second), as well as precipitation over the sea which is around 180mm/year in Qeshm Island. The evaporation of the sea is high, so that after considering river discharge and rain contributions, there is still a deficit of 416 cubic kilometers per year.[9] This difference is supplied by currents at the Strait of Hormuz. The water from the Gulf has a higher salinity, and therefore exits from the bottom of the Strait, while ocean water with less salinity flows in through the top. Another study revealed the following numbers for water exchanges for the Gulf: evaporation = -1.84m/year, precipitation = 0.08m/year, inflow from the Strait = 33.66m/year, outflow from the Strait = -32.11m/year, and the balance is 0m/year.[10] Data from different 3D computational fluid mechanics models, typically with spatial resolution of 3 kilometers and depth each element equal to 1–10 meters are predominantly used in computer models.
Oil and gas

The Persian Gulf and its coastal areas are the world's largest single source of crude oil, and related industries dominate the region. Safaniya Oil Field, the world's largest offshore oilfield, is located in the Persian Gulf. Large gas finds have also been made, with Qatar and Iran sharing a giant field across the territorial median line (North Field in the Qatari sector; South Pars Field in the Iranian sector). Using this gas, Qatar has built up a substantial liquefied natural gas (LNG) and petrochemical industry.
In 2002, the Persian Gulf nations of Bahrain, Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the UAE produced about 25% of the world's oil, held nearly two-thirds of the world's crude oil reserves, and about 35% of the world's natural gas reserves.[11][12] The oil-rich countries (excluding Iraq) that have a coastline on the Persian Gulf are referred to as the Persian Gulf States. Iraq's egress to the gulf is narrow and easily blockaded consisting of the marshy river delta of the Shatt al-Arab, which carries the waters of the Euphrates and the Tigris rivers, where the east bank is held by Iran.
Name

In 550 BC, the Achaemenid Empire established the first ancient empire in Persis (Pars, or modern Fars), in the southwestern region of the Iranian plateau. Consequently, in the Greek sources, the body of water that bordered this province came to be known as the "Persian Gulf".[13]
During the years 550 to 330 BC, coinciding with the sovereignty of the Achaemenid Persian Empire over the Middle East area, especially the whole part of the Persian Gulf and some parts of the Arabian Peninsula, the name of "Pars Sea" is widely found in the compiled written texts.[1]
In the travel account of Pythagoras, several chapters are related to description of his travels accompanied by the Achaemenid king Darius the Great, to Susa and Persepolis, and the area is described. From among the writings of others in the same period, there is the inscription and engraving of Darius the Great, installed at junction of waters of Red Sea and the Nile river and the Rome river (current Mediterranean) which belongs to the 5th century BC where Darius the Great has named the Persian Gulf Water Channel: "Pars Sea" ("Persian Sea").[1]
Considering the historical background of the name Persian Gulf, Sir Arnold Wilson mentions in a book published in 1928 that "no water channel has been so significant as Persian Gulf to the geologists, archaeologists, geographers, merchants, politicians, excursionists, and scholars whether in past or in present. This water channel which separates the Iran Plateau from the Arabia Plate, has enjoyed an Iranian Identity since at least 2200 years ago."[1]
Before being given its present name, the Persian Gulf was called many different names. The classical Greek writers, like Herodotus, called it "the Red Sea". In Babylonian texts, it was known as "the sea above Akkad".
Naming dispute

The name of the gulf, historically and internationally known as the Persian Gulf after the land of Persia (Iran), has been disputed by some Arab countries since the 1960s.[16] Rivalry between Iran and some Arab states, along with the emergence of pan-Arabism and Arab nationalism, has seen the name Arabian Gulf become predominant in most Arab countries.[17][18] Names beyond these two have also been applied to or proposed for this body of water.
History
Ancient history

Earliest evidence of human presence on Persian Gulf islands dates back to Middle Paleolithic and consist of stone tools discovered at Qeshm Island[19].The world's oldest known civilization (Sumer) developed along the Persian Gulf and southern Mesopotamia. The shallow basin that now underlies the Gulf was an extensive region of river valley and wetlands during the transition between the end of the Last Glacial Maximum and the start of the Holocene, which, according to University of Birmingham archaeologist Jeffrey Rose, served as an environmental refuge for early humans during periodic hyperarid climate oscillations, laying the foundations for the legend of Dilmun.[20]
For most of the early history of the settlements in the Persian Gulf, the southern shores were ruled by a series of nomadic tribes. During the end of the fourth millennium BC, the southern part of the Persian Gulf was dominated by the Dilmun civilization. For a long time the most important settlement on the southern coast of the Persian Gulf was Gerrha. In the 2nd century the Lakhum tribe, who lived in what is now Yemen, migrated north and founded the Lakhmid Kingdom along the southern coast. Occasional ancient battles took place along the Persian Gulf coastlines, between the Sassanid Persian empire and the Lakhmid Kingdom, the most prominent of which was the invasion led by Shapur II against the Lakhmids, leading to Lakhmids' defeat, and advancement into Arabia, along the southern shore lines.[21] During the 7th century the Sassanid Persian empire conquered the whole of the Persian Gulf, including southern and northern shores.
Between 625 BC and 226 AD, the northern side was dominated by a succession of Persian empires including the Median, Achaemenid, Seleucid and Parthian empires. Under the leadership of the Achaemenid king Darius the Great (Darius I), Persian ships found their way to the Persian Gulf.[22] Persian naval forces laid the foundation for a strong Persian maritime presence in Persian Gulf, that started with Darius I and existed until the arrival of the British East India Company, and the Royal Navy by mid-19th century AD. Persians were not only stationed on islands of the Persian Gulf, but also had ships often of 100 to 200 capacity patrolling empire's various rivers including Shatt-al-Arab, Tigris, and the Nile in the west, as well as Sind waterway, in India.[22]
The Achaemenid high naval command had established major naval bases located along Shatt al-Arab river, Bahrain, Oman, and Yemen. The Persian fleet would soon not only be used for peacekeeping purposes along the Shatt al-Arab but would also open the door to trade with India via Persian Gulf.[22][23]
Following the fall of Achaemenid Empire, and after the fall of the Parthian Empire, the Sassanid empire ruled the northern half and at times the southern half of the Persian Gulf. The Persian Gulf, along with the Silk Road, were important trade routes in the Sassanid empire. Many of the trading ports of the Persian empires were located in or around Persian Gulf. Siraf, an ancient Sassanid port that was located on the northern shore of the gulf, located in what is now the Iranian province of Bushehr, is an example of such commercial port. Siraf, was also significant in that it had a flourishing commercial trade with China by the 4th century, having first established connection with the far east in 185 AD.[24]
Colonial era

Portuguese expansion into the Indian Ocean in the early 16th century following Vasco da Gama's voyages of exploration saw them battle the Ottomans up the coast of the Persian Gulf. In 1521, a Portuguese force led by commander Antonio Correia invaded Bahrain to take control of the wealth created by its pearl industry. On April 29, 1602, Shāh Abbās, the Persian emperor of the Safavid Persian Empire expelled the Portuguese from Bahrain,[25] and that date is commemorated as National Persian Gulf day in Iran.[26] With the support of the British fleet, in 1622 'Abbās took the island of Hormuz from the Portuguese; much of the trade was diverted to the town of Bandar 'Abbās, which he had taken from the Portuguese in 1615 and had named after himself. The Persian Gulf was therefore opened by Persians to a flourishing commerce with the Portuguese, Dutch, French, Spanish and the British merchants, who were granted particular privileges.
The Ottoman Empire reasserted itself into Eastern Arabia in 1871.[27] Under military and political pressure from the governor of the Ottoman Vilayet of Baghdad, Midhat Pasha, the ruling Al Thani tribe submitted peacefully to Ottoman rule.[28] The Ottomans were forced to withdraw from the area with the start of World War I and the need for troops in various other frontiers.[29]
In World War II, the Western Allies used Iran as a conduit to transport military and industrial supply to the USSR, through a pathway known historically as the "Persian Corridor". Britain utilized the Persian Gulf as the entry point for the supply chain in order to make use of the Trans-Iranian Railway.[30] The Persian Gulf therefore became a critical maritime path through which the Allies transported equipment to Russia against the Nazi invasion.[31]
From 1763 until 1971, the British Empire maintained varying degrees of political control over some of the Persian Gulf states, including the United Arab Emirates (originally called the Trucial States)[32][33] and at various times Bahrain, Kuwait, Oman, and Qatar through the British Residency of the Persian Gulf.
The United Kingdom maintains a high profile in the region to date; in 2006 alone, over 1 million British nationals visited Dubai.[34][35] In 2014, the UK announced it will reestablish a permanent military base, HMS Jufair, in the Persian Gulf, the first since it withdrew from East of Suez in 1971.[36][37][38]
Islands

The Persian Gulf is home to many islands such as Bahrain, an Arab state. Geographically the biggest island in the Persian Gulf is Qeshm island located in the Strait of Hormuz and belongs to Iran. Other significant islands in the Persian Gulf include Greater Tunb, Lesser Tunb and Kish administered by Iran, Bubiyan administered by Kuwait, Tarout administered by Saudi Arabia, and Dalma administered by UAE. In recent years, there has also been addition of artificial islands for tourist attractions, such as The World Islands in Dubai and The Pearl-Qatar in Doha. Persian Gulf islands are often also historically significant, having been used in the past by colonial powers such as the Portuguese and the British in their trade or as acquisitions for their empires.[39]
Cities and population
Eight nations have coasts along the Persian Gulf: Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates. The gulf's strategic location has made it an ideal place for human development over time. Today, many major cities of the Middle East are located in this region.

Abu Dhabi, United Arab Emirates
Doha, Qatar
Dubai, United Arab Emirates
Kuwait City, Kuwait
Manama, Bahrain
Bandar Abbas, Iran
Khasab, Oman
Khobar City, Saudi Arabia

Wildlife

The wildlife of the Persian Gulf is diverse, and entirely unique due to the gulf's geographic distribution and its isolation from the international waters only breached by the narrow Strait of Hormuz. The Persian Gulf has hosted some of the most magnificent marine fauna and flora, some of which are near extirpation or at serious environmental risk. From corals, to dugongs, Persian Gulf is a diverse cradle for many species who depend on each other for survival. However, the gulf is not as biologically diverse as the Red Sea.[40]
Overall, the wild life of the Persian Gulf is endangered from both global factors, and regional, local negligence. Most pollution is from ships; land generated pollution counts as the second most common source of pollution.[41]
Aquatic mammals

Along the mediterranean regions of the Arabian Sea, including the Persian Gulf, the Red Sea, the Gulf of Kutch, the Gulf of Suez, the Gulf of Aqaba, the Gulf of Aden, and the Gulf of Oman, dolphins and finless porpoises are the most common marine mammals in the waters, while larger whales and orcas are rarer today.[42] Historically, whales had been abundant in the gulf before commercial hunts wiped them out.[43][44] Whales were reduced even further by illegal mass hunts by the Soviet Union and Japan in the 1960s and 1970s.[45] Along with Bryde's whales,[46][47][48][49] these once common residents can still can be seen in deeper marginal seas such as Gulf of Aden,[50] Israel coasts,[51] and in the Strait of Hormuz.[52] Other species such as the critically endangered Arabian humpback whale,[53] (also historically common in Gulf of Aden[54] and increasingly sighted in the Red Sea since 2006, including in the Gulf of Aqaba),[51] omura's whale,[55][56] minke whale, and orca also swim into the gulf, while many other large species such as blue whale,[57] sei,[58] and sperm whales were once migrants into the Gulf of Oman and off the coasts in deeper waters,[59] and still migrate into the Red Sea,[60] but mainly in deeper waters of outer seas. In 2017, waters of the Persian Gulf along Abu Dhabi were revealed to hold the world's largest population of Indo-Pacific humpbacked dolphins.[61][62][63]
One of the more unusual marine mammals living in the Persian Gulf is the dugong (Dugong dugon). Also called "sea cows", for their grazing habits and mild manner resembling livestock, dugongs have a life expectancy similar to that of humans and they can grow up to 3 metres (9.8 feet) in length. These gentle mammals feed on sea grass and are closer relatives of certain land mammals than are dolphins and whales.[64] Their simple grass diet is negatively affected by new developments along the Persian Gulf coastline, particularly the construction of artificial islands by Arab states and pollution from oil spills caused during the "Persian Gulf war" and various other natural and artificial causes. Uncontrolled hunting has also had a negative impact on the survival of dugongs.[64] After Australian waters, which are estimated to contain some 80,000 dugong inhabitants, the waters off Qatar, Bahrain, UAE, and Saudi Arabia make the Persian Gulf the second most important habitat for the species, hosting some 7,500 remaining dugongs. However, the current number of dugongs is dwindling and it is not clear how many are currently alive or what their reproductive trend is.[64][65] Unfortunately, ambitious and uncalculated construction schemes, political unrest, ever-present international conflict, the most lucrative world supply of oil, and the lack of cooperation between Arab states and Iran, have had a negative impact on the survival of many marine species, including dugongs.
Birds
The Persian Gulf is also home to many migratory and local birds. There is great variation in color, size, and type of the bird species that call the gulf home. Concerns regarding the endangerment of the kalbaensis subspecies of the collared kingfishers were raised by conservationists due to real state development by the United Arab Emirates and Oman.[66] Estimates from 2006 showed that only three viable nesting sites were available for this ancient bird, one located 80 miles (129km) from Dubai, and two smaller sites in Oman.[66] Such real estate expansion could prove devastating to this subspecies. A UN plan to protect the mangroves as a biological reserve was ignored by the emirate of Sharjah, which allowed the dredging of a channel that bisects the wetland and construction of an adjacent concrete walkway.[66] Environmental watchdogs in Arabia are few, and those that do advocate the wildlife are often silenced or ignored by developers of real estate many of whom have governmental connections.[66]
Real estate development in the Persian Gulf by the United Arab Emirates and Oman also raised concerns that habitats of species such as the hawksbill turtle, greater flamingo, and booted warbler may be destroyed.[66][67] The dolphins that frequent the gulf in northern waters around Iran are also at risk. Recent statistics and observations show that dolphins are at danger of entrapment in purse seine fishing nets and exposure to chemical pollutants; perhaps the most alarming sign is the "mass suicides" committed by dolphins off Iran's Hormozgan province, which are not well understood, but are suspected to be linked with a deteriorating marine environment from water pollution from oil, sewage, and industrial run offs.[68][69]
Fish and reefs
The Persian Gulf is home to over 700 species of fish, most of which are native.[70] Of these 700 species, more than 80% are reef associated.[70] These reefs are primarily rocky, but there are also a few coral reefs. Compared to the Red Sea, the coral reefs in the Persian Gulf are relatively few and far between.[71][72][73] This is primarily connected to the influx of major rivers, especially the Shatt al-Arab (Euphrates and Tigris), which carry large amounts of sediment (most reef-building corals require strong light) and causes relatively large variations in temperature and salinity (corals in general are poorly suited to large variations).[71][72][73] Nevertheless, coral reefs have been found along sections of coast of all countries in the Gulf.[73] Corals are vital ecosystems that support multitude of marine species, and whose health directly reflects the health of the gulf. Recent years have seen a drastic decline in the coral population in the gulf, partially owing to global warming but majorly due to irresponsible dumping by Arab states like the UAE and Bahrain.[74] Construction garbage such as tires, cement, and chemical by products have found their way to the Persian Gulf in recent years. Aside from direct damage to the coral, the construction waste creates "traps" for marine life in which they are trapped and die.[74] The end result has been a dwindling population of the coral, and as a result a decrease in number of species that rely on the corals for their survival.
Flora
A great example of this symbiosis are the mangroves in the gulf, which require tidal flow and a combination of fresh and salt water for growth, and act as nurseries for many crabs, small fish, and insects; these fish and insects are the source of food for many of the marine birds that feed on them.[66] Mangroves are a diverse group of shrubs and trees belonging to the genus Avicennia or Rhizophora that flourish in the salt water shallows of the gulf, and are the most important habitats for small crustaceans that dwell in them. They are as crucial an indicator of biological health on the surface of the water, as the corals are to biological health of the gulf in deeper waters. Mangroves' ability to survive the salt water through intricate molecular mechanisms, their unique reproductive cycle, and their ability to grow in the most oxygen-deprived waters have allowed them extensive growth in hostile areas of the gulf.[75][76] However, with the advent of artificial island development, most of their habitat is destroyed, or occupied by man-made structures. This has had a negative impact on the crustaceans that rely on the mangrove, and in turn on the species that feed on them.
Gallery

Dugong mother and her offspring in shallow water.
Indo-Pacific bottlenose dolphins off the southern shore of Iran, around Hengam Island.
Spinner dolphins leaping in the gulf.
Critically endangered Arabian humpback whales (being the most isolated, and the only resident population in the world) off Dhofar.
Palm and sunset in Minoo Island (Persian Gulf).

See also
Arab cuisine of the Persian Gulf
Cradle of civilization
Deluge (prehistoric)
Gulf of Aden
Musandam Peninsula
Piracy in the Persian Gulf

 – an online portal providing access to previously undigitised British Library archive materials relating to Gulf history and Arabic science

, at flickr.com
 from 1920
Videos
 (PressTV 2012)

[

Which countries border the Persian Gulf?