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94-506: The Maasai and Sonjo people refer to the volcano as "The Mountain of God", associated with a myth of the abode of the god Engai , who withdrew there after being hit by a hunter with an arrow. Other names are Basanjo, Donjo Ngai, Duenjo Ngai, Mongogogura, Mungogo wa Bogwe, and Oldonyo L'Engai. Ol Doinyo Lengai lies in the Arusha region of Tanzania, 16 kilometres (9.9 mi) south of Lake Natron and 120 kilometres (75 mi) northwest of

188-645: A Nilotic ethnic group inhabiting northern, central and southern Kenya and northern Tanzania , near the African Great Lakes region. Their native language is the Maasai language , a Nilotic language related to Dinka , Kalenjin and Nuer . Except for some elders living in rural areas, most Maasai people speak the official languages of Kenya and Tanzania— Swahili and English . The Maasai population has been reported as numbering 1,189,522 in Kenya in

282-885: A 300-page report by the National Institutes of Health linked flouridation of drinking water in the United States, in areas where levels are slightly more than twice the recommended limit, to lower IQ in developing children. Around one-third of the human population drinks water from groundwater resources. Of this, about 10%, approximately 300 million people, obtain water from groundwater resources that are heavily contaminated with arsenic or fluoride. These trace elements derive mainly from minerals. Maps locating potential problematic wells are available. Concentrated fluoride solutions are corrosive. Gloves made of nitrile rubber are worn when handling fluoride compounds. The hazards of solutions of fluoride salts depend on

376-568: A dance". ) Traditionally, the Maasai diet consisted of raw meat, raw milk, honey and raw blood from cattle —note that the Maasai cattle are of the Zebu variety. Most of the milk is consumed as fermented milk or buttermilk (a by-product of butter making). Milk consumption figures are very high by any standards. The Maasai herd goats and sheep, including the Red Maasai sheep , as well as

470-427: A day, can potentially supply the daily recommended intake of 4 mg per day. Some lower quality brands can supply up to a 120% of this amount. Fasting can increase this to 150%. The study indicates that tea drinking communities are at an increased risk of dental and skeletal fluorosis , in the case where water fluoridation is in effect. Fluoride ion in low doses in the mouth reduces tooth decay. For this reason, it

564-664: A descending scale, and singers responding to their verses are characteristic of singing by women. When many Maasai women gather together, they sing and dance among themselves. Eunoto, the coming-of-age ceremony of the warrior, can involve ten or more days of singing, dancing and ritual. The warriors of the Il-Oodokilani perform a kind of march-past as well as the Adumu , or aigus, sometimes referred to as "the jumping dance" by non-Maasai. (Both adumu and aigus are Maa verbs meaning "to jump" with adumu meaning "To jump up and down in

658-583: A dual nature, represented by two colours: Engai Narok (Black God) is benevolent, and Engai Na-nyokie (Red God) is vengeful. There are also two pillars or totems of Maasai society: Oodo Mongi, the Red Cow and Orok Kiteng, the Black Cow with a subdivision of five clans or family trees . The Maasai also have a totemic animal, which is the lion. The killing of a lion is used by the Maasai in the rite of passage ceremony. The "Mountain of God", Ol Doinyo Lengai ,

752-425: A multitude of ways including being boiled in soups and ingested to improve digestion and cleanse the blood. Some of these remedies can also be used in the treatment or prevention of diseases. The Maasai people also add herbs to different foods to avoid stomach upsets and give digestive aid. The use of plant-based medicine remains an important part of Maasai life. Maasai clothing symbolises ethnic group membership,

846-465: A pastoralist lifestyle, as well as an individual's social position. From this they can decide the roles they undertake for the tribe. Jewellery also can show an individual's gender, relationship status, and age. Maasai traditional clothing is both a means of tribal identification and symbolism: young men, for example, wear black for several months following their circumcision. Fluoride Fluoride ( / ˈ f l ʊər aɪ d , ˈ f l ɔːr -/ )

940-560: A reputation as fearsome warriors and cattle rustlers. The Maasai and other groups in East Africa have adopted customs and practices from neighbouring Cushitic-speaking groups, including the age-set system of social organisation, circumcision , and vocabulary terms. Many ethnic groups that had already formed settlements in the region were forcibly displaced by the incoming Maasai. Other, mainly Southern Cushitic groups, were assimilated into Maasai society. The Nilotic ancestors of

1034-460: A scar on the volcano's flanks. Their occurrence may have been influenced by regional fault systems. Ol Doinyo Lengai is part of the Gregory Rift , which is part of the active East African Rift . The East African Rift is a continental rift extending from eastern to southern Africa over a length of 4,000 kilometres (2,500 mi), where there is high heat flow through a thinner crust . In

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1128-498: A separate origin from the other volcanic rocks. There appear to be two magma reservoirs under the volcano, and its plumbing system is complex, involving regional tectonic structures. Volcanic gas sampled at Ol Doinyo Lengai consists mostly of water vapor and carbon dioxide and originates in the mantle . The volcano is a major source of volcanic carbon dioxide, producing about 80 kilograms per second (11,000 lb/min) of CO 2 . Radiometric dates obtained by geologists for

1222-465: Is fluoridated this can be expected to be a significant source of fluoride, however fluoride is also naturally present in virtually all foods and beverages at a wide range of concentrations. The maximum safe daily consumption of fluoride is 10 mg/day for an adult (U.S.) or 7 mg/day (European Union). The upper limit of fluoride intake from all sources (fluoridated water, food, beverages, fluoride dental products and dietary fluoride supplements)

1316-506: Is shaved off ; elders must wear their hair short. Warriors who do not have sexual relations with women who have not undergone the "Emuatare" ceremony are especially honoured at the Eunoto gathering. This would symbolise the healing of the woman. Two days before boys are circumcised, their heads are shaved. When warriors go through the Eunoto and become elders, their long plaited hair

1410-416: Is a commodity chemical used in steel-making. Uranium hexafluoride is employed in the purification of uranium isotopes. Fluoride-containing compounds, such as sodium fluoride or sodium monofluorophosphate are used in topical and systemic fluoride therapy for preventing tooth decay . They are used for water fluoridation and in many products associated with oral hygiene . Originally, sodium fluoride

1504-440: Is a major reagent and precursor to reagents. Hydrofluoric acid and its anhydrous form, hydrogen fluoride , are particularly important. The main uses of fluoride, in terms of volume, are in the production of cryolite, Na 3 AlF 6 . It is used in aluminium smelting . Formerly, it was mined, but now it is derived from hydrogen fluoride. Fluorite is used on a large scale to separate slag in steel-making. Mined fluorite (CaF 2 )

1598-400: Is absorbed from soil and water. Some plants concentrate fluoride from their environment more than others. All tea leaves contain fluoride; however, mature leaves contain as much as 10 to 20 times the fluoride levels of young leaves from the same plant. Fluoride can act as a base . It can combine with a proton (   H ): This neutralization reaction forms hydrogen fluoride (HF),

1692-492: Is also a trivial name , and the preferred IUPAC name for fluorane . Fluorine is estimated to be the 13th-most abundant element in Earth's crust and is widely dispersed in nature, entirely in the form of fluorides. The vast majority is held in mineral deposits , the most commercially important of which is fluorite (CaF 2 ). Natural weathering of some kinds of rocks, as well as human activities, releases fluorides into

1786-410: Is an inorganic , monatomic anion of fluorine , with the chemical formula F (also written [F] ), whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons . Fluoride

1880-469: Is called "naked". Naked fluoride is a strong Lewis base , and a powerful nucleophile. Some quaternary ammonium salts of naked fluoride include tetramethylammonium fluoride and tetrabutylammonium fluoride . Cobaltocenium fluoride is another example. However, they all lack structural characterization in aprotic solvents. Because of their high basicity, many so-called naked fluoride sources are in fact bifluoride salts. In late 2016 imidazolium fluoride

1974-731: Is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin. Fluoride is the simplest fluorine anion . In terms of charge and size, the fluoride ion resembles the hydroxide ion. Fluoride ions occur on Earth in several minerals, particularly fluorite , but are present only in trace quantities in bodies of water in nature. Fluorides include compounds that contain ionic fluoride and those in which fluoride does not dissociate. The nomenclature does not distinguish these situations. For example, sulfur hexafluoride and carbon tetrafluoride are not sources of fluoride ions under ordinary conditions. The systematic name fluoride ,

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2068-408: Is delivered to the populace by fluoridating table salt. For the method of action for cavity prevention, see Fluoride therapy . Fluoridation of water has its critics (see Water fluoridation controversy ) . Fluoridated toothpaste is in common use. Meta-analysis show the efficacy of 500 ppm fluoride in toothpastes. However, no beneficial effect can be detected when more than one fluoride source

2162-578: Is equivalent to 32 to 64 mg elemental fluoride per kg body weight). A case of a fatal poisoning of an adult with 4 grams of sodium fluoride is documented, and a dose of 120 g sodium fluoride has been survived. For sodium fluorosilicate (Na 2 SiF 6 ), the median lethal dose (LD 50 ) orally in rats is 125 mg/kg, corresponding to 12.5 g for a 100 kg adult. Treatment may involve oral administration of dilute calcium hydroxide or calcium chloride to prevent further absorption, and injection of calcium gluconate to increase

2256-473: Is evidence of underground magma intrusions. Satellite observations have shown deformation of the volcano during eruptions, and ground-based observations have identified movement in neighboring fault systems such as the Natron Fault caused by magma originating at Ol Doinyo Lengai. After a phase of quiescence, renewed activity commenced in 1983 and continues with several interruptions to this day. During

2350-446: Is formed by a 110-metre (360-foot) high ridge. The floor of the northern crater is covered with lava flows that resemble pahoehoe lavas. Small cones with sizes ranging from 2 metres (6 ft 7 in) to over 10 metres (33 ft) occur in the crater and produce lava flows from their summits and, when they collapse, from their flanks. The southern crater is inactive and sometimes filled with water. White volcanic ash deposits cover

2444-408: Is located in northernmost Tanzania and can be seen from Lake Natron in southernmost Kenya. The central human figure in the Maasai religious system is the laibon whose roles include shamanistic healing , divination and prophecy , and ensuring success in war or adequate rainfall. Today, they have a political role as well due to the elevation of leaders. Whatever power an individual laibon had

2538-447: Is more strongly solvated in protic solvents due to its smaller radius/charge ratio. Its closest chemical relative is hydroxide , since both have similar geometries. Most fluoride salts dissolve to give the bifluoride ( HF 2 ) anion. Sources of true F anions are rare because the highly basic fluoride anion abstracts protons from many, even adventitious, sources. Relative unsolvated fluoride, which does exist in aprotic solvents,

2632-465: Is mostly mild and is unlikely to represent any real effect on aesthetic appearance or on public health. Fluoride was known to enhance bone mineral density at the lumbar spine, but it was not effective for vertebral fractures and provoked more nonvertebral fractures. In areas that have naturally occurring high levels of fluoride in groundwater which is used for drinking water , both dental and skeletal fluorosis can be prevalent and severe. In 2024,

2726-400: Is named and the head is shaved clean apart from a tuft of hair, which resembles a cockade , from the nape of the neck to the forehead. Among the men, warriors are the only members of the Maasai community to wear long hair, which they weave in thinly braided strands. Graduation from warrior to junior elder takes place at a large gathering known as Eunoto. The long hair of the former warriors

2820-425: Is not uncommon for bodies to be covered in fat and blood from a slaughtered ox . Traditional Maasai lifestyle centres around their cattle , which constitute their primary source of food. In a patriarchal culture that views women as property, a man's wealth is measured in cattle, wives and children. A herd of 50 cattle is respectable, and the more wives and children the better. A man who has plenty of one but not

2914-515: Is now Tanzania. Maasai are pastoralists and have resisted the urging of the Tanzanian and Kenyan governments to adopt a more sedentary lifestyle. They have demanded grazing rights to many of the national parks in both countries. The Maasai people stood against slavery and never condoned the traffic of human beings, and outsiders looking for people to enslave avoided the Maasai. Essentially there are twenty-two geographic sectors or sub-tribes of

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3008-401: Is potentially a vehicle for fluoride dosing. Approximately, 50% of absorbed fluoride is excreted renally with a twenty-four-hour period. The remainder can be retained in the oral cavity, and lower digestive tract. Fasting dramatically increases the rate of fluoride absorption to near 100%, from a 60% to 80% when taken with food. Per a 2013 study, it was found that consumption of one litre of tea

3102-632: Is set at 0.10 mg/kg/day for infants, toddlers, and children through to 8 years old. For older children and adults, who are no longer at risk for dental fluorosis, the upper limit of fluoride is set at 10 mg/day regardless of weight. According to the U.S. Department of Agriculture, the Dietary Reference Intakes, which is the "highest level of daily nutrient intake that is likely to pose no risk of adverse health effects" specify 10 mg/day for most people, corresponding to 10 L of fluoridated water with no risk. For young children

3196-467: Is shaved off. Maasai music traditionally consists of rhythms provided by a chorus of vocalists singing harmonies while a song leader, or olaranyani, sings the melody. Unlike most other African tribes, Maasai widely use drone polyphony . Women chant lullabies, humming songs, and songs praising their sons. Nambas, the call-and-response pattern, repetition of nonsensical phrases, monophonic melodies, repeated phrases following each verse being sung on

3290-769: Is the only volcano on Earth known to have erupted carbonatitic lavas during historical times, although these rocks make up only a small fraction of the volcano and only occur in the northern crater; they only recently appeared on the volcano. The properties of Ol Doinyo Lengai's magmas have been used as an analogue for the conditions on carbon planets ; these are planets which are rich in carbon. Chemical composition: The carbonatite lavas are rapidly chemically modified by rainfall or covered by deposits condensing from fumarolic gases, yielding secondary minerals like calcite , gaylussite , nahcolite , pirssonite , shortite , thermonatrite , and trona , including various chlorides , fluorides , and sulfates . These rocks form crusts on

3384-403: Is used for daily oral care. Fluoride salts are commonly used in biological assay processing to inhibit the activity of phosphatases , such as serine / threonine phosphatases. Fluoride mimics the nucleophilic hydroxide ion in these enzymes' active sites. Beryllium fluoride and aluminium fluoride are also used as phosphatase inhibitors, since these compounds are structural mimics of

3478-441: Is used in toothpaste and water fluoridation. At much higher doses and frequent exposure, fluoride causes health complications and can be toxic. Fluoride salts and hydrofluoric acid are the main fluorides of industrial value. Organofluorine compounds are pervasive. Many drugs, many polymers, refrigerants, and many inorganic compounds are made from fluoride-containing reagents. Often fluorides are converted to hydrogen fluoride, which

3572-532: The Arabian Peninsula , and later spread this ancestry component southwards into certain Khoisan groups roughly 2,000 years ago, resulting in ~5% West-Eurasian ancestry among Southern African hunter-gatherers. A 2019 archaeogenetic study sampled ancient remains from Neolithic inhabitants of Tanzania and Kenya, and found them to have strongest affinities with modern Horn of Africa groups. They modelled

3666-549: The Ngorongoro and other volcanoes. Over time, volcanic activity shifted northeastward to the present-day Ol Doinyo Lengai. Other volcanoes in the area are Gelai to the northeast and Ketumbeine southeast of Ol Doinyo Lengai; further away are the Olduvai Gorge to the west and Kilimanjaro mountain east of the volcano. Most of the volcanic cone is formed by melilite , nephelinite , and phonolite . Ol Doinyo Lengai

3760-453: The biosphere through what is sometimes called the fluorine cycle . Fluoride is naturally present in groundwater, fresh and saltwater sources, as well as in rainwater, particularly in urban areas. Seawater fluoride levels are usually in the range of 0.86 to 1.4 mg/L, and average 1.1 mg/L (milligrams per litre ). For comparison, chloride concentration in seawater is about 19 g/L. The low concentration of fluoride reflects

3854-439: The conjugate acid of fluoride. In aqueous solution, fluoride has a p K b value of 10.8. It is therefore a weak base , and tends to remain as the fluoride ion rather than generating a substantial amount of hydrogen fluoride. That is, the following equilibrium favours the left-hand side in water: However, upon prolonged contact with moisture, soluble fluoride salts will decompose to their respective hydroxides or oxides, as

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3948-453: The ethnogenesis of the Maasai people. Genetic genealogy , a tool that uses the genes of modern populations to trace their ethnic and geographic origins, has also helped clarify the possible background of modern Maasai. The Maasai's autosomal DNA has been examined in a comprehensive study by Tishkoff et al. (2009) on the genetic affiliations of various populations in Africa. According to

4042-440: The phosphate group and can act as analogues of the transition state of the reaction. The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for some minerals in 1997. Where there was not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake (AI) was used instead. AIs are typically matched to actual average consumption, with

4136-455: The 111 children examined exhibited missing mandibular or maxillary deciduous canines. Traditionally, the Maasai conduct elaborate rite of passage rituals which include surgical genital mutilation to initiate children into adulthood. The Maa word for circumcision , "emorata," is applied to this ritual for both males and females. This ritual is typically performed by the elders, who use a sharpened knife and makeshift cattle hide bandages for

4230-474: The 1983 eruption, ashfall occurred at tens of kilometers from the volcano. The emission of a lava flow onto the western flank of Ol Doinyo Lengai in 2006 was accompanied by the formation of a pit crater on the summit. A large explosive eruption began on the 4 September 2007, producing a 3-kilometre (1.9 mi)-high eruption column and a new crater 100 metres (330 ft) deep and 300 metres (980 ft) wide. The explosive activity continued into 2008, when

4324-516: The 2019 census, compared to 377,089 in the 1989 census, though many Maasai view the census as government meddling and therefore either refuse to participate or actively provide false information. The Maasai inhabit the African Great Lakes region and arrived via South Sudan . Most Nilotic speakers in the area, including the Maasai, the Turkana and the Kalenjin , are pastoralists and have

4418-516: The Gregory Rift, spreading began about 1.2 million years ago and is ongoing at a rate of about 3 millimetres per year (0.12 in/year). The Natron Fault , the western boundary of the Gregory Rift in the area, passes just southwest of the volcano. The volcano is part of the Ngorongoro volcanic highland , a system of volcanoes that were active from the Miocene to present, and which includes

4512-634: The IOM sets tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of fluoride the UL is 10 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL are defined

4606-840: The Kalenjin likewise absorbed some early Cushitic populations. The Maasai territory reached its largest size in the mid-19th century and covered almost all of the Great Rift Valley and adjacent lands from Mount Marsabit in the north to Dodoma in the south. At this time the Maasai, as well as the larger Nilotic group they were part of, raised cattle as far east as the Tanga coast in Tanganyika (now mainland Tanzania). Raiders used spears and shields but were most feared for throwing clubs (orinka) which could be accurately thrown from up to 70 paces (approx. 100 metres). In 1852, there

4700-474: The Maasai as goat leaves). One common misconception about the Maasai is that each young man is supposed to kill a lion before he can be circumcised and enter adulthood. Lion hunting was an activity of the past, but it has been banned in East Africa – yet lions are still hunted when they maul Maasai livestock. Nevertheless, killing a lion gives one great value and celebrity status in the community. The piercing and stretching of earlobes are common among

4794-401: The Maasai as with other tribes, and both men and women wear metal hoops on their stretched earlobes. Various materials have been used to both pierce and stretch the lobes, including thorns for piercing, twigs, bundles of twigs, stones, the cross-section of elephant tusks and empty film canisters. Women wear various forms of beaded ornaments in both the ear lobe and smaller piercings at the top of

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4888-440: The Maasai community as having ancestry that is ~47% Pastoral Neolithic Cushitic-related and ~53% Sudanese Dinka-related. A Y chromosome study by Wood et al. (2005) tested various Sub-Saharan populations, including 26 Maasai men from Kenya, for paternal lineages. The authors observed haplogroup E1b1b -M35 (not M78) in 35% of the studied Maasai. E1b1b-M35-M78 in 15%, their ancestor with the more northerly Cushitic men, who possess

4982-585: The Maasai community, each one having its customs, appearance, leadership and dialects. These subdivisions are known as 'nations' or 'iloshon' in the Maa language : the Keekonyokie , Ildamat, Purko, Wuasinkishu, Siria, Laitayiok, Loitai, Ilkisonko, Matapato, Dalalekutuk, Ilooldokilani, Ilkaputiei, Moitanik, Ilkirasha, Samburu , Ilchamus, Laikipiak , Loitokitoki, Larusa, Salei, Sirinket and Parakuyo . Recent advances in genetic analyses have helped shed some light on

5076-465: The Olduvai Gorge. The volcano collapsed several times, including once between 850,000 and 135,000 years ago and another time between 50,000 and 10,000 years ago. The oldest natrocarbonatite lavas date to 1,250 years before present . An eruption 3,000-2,500 years before present produced a tephra fallout west of Ol Doinyo Lengai, that is presently being eroded by wind and forming dunes including

5170-569: The Shifting Sands of the Olduvai Gorge. A large eruption deposited the Namorod Ash in the gorge, about 1,250 years ago, and another about 600 years ago formed the so-called "Footprint Tuff". Ol Doinyo Lengai is the only presently active volcano of the Gregory Rift. Records of eruptions go back to the 1880s. The volcano is continually active, but there are seldom observations of its activity. It erupts tephra and lava flows from within

5264-454: The amount of a vitamin or mineral in a serving is expressed as a percent of Daily Value (%DV). Although there is information to set Adequate Intake, fluoride does not have a Daily Value and is not required to be shown on food labels. Daily intakes of fluoride can vary significantly according to the various sources of exposure. Values ranging from 0.46 to 3.6–5.4 mg/day have been reported in several studies (IPCS, 1984). In areas where water

5358-423: The assumption that there appears to be a need, and that need is met by what people consume. The current AI for women 19 years and older is 3.0 mg/day (includes pregnancy and lactation). The AI for men is 4.0 mg/day. The AI for children ages 1–18 increases from 0.7 to 3.0 mg/day. The major known risk of fluoride deficiency appears to be an increased risk of bacteria-caused tooth cavities. As for safety,

5452-435: The calcium levels in the blood. Hydrogen fluoride is more dangerous than salts such as NaF because it is corrosive and volatile, and can result in fatal exposure through inhalation or upon contact with the skin; calcium gluconate gel is the usual antidote. In the higher doses used to treat osteoporosis , sodium fluoride can cause pain in the legs and incomplete stress fractures when the doses are too high; it also irritates

5546-544: The ceremony that initiates young Maasai girls into adulthood through ritual mutilation and then into early arranged marriages. The Maasai believe that female genital mutilation is necessary and Maasai men may reject any woman who has not undergone it as either not marriageable or worthy of a much-reduced bride price. In Eastern Africa, uncircumcised women, even highly educated members of parliament like Linah Kilimo , can be accused of not being mature enough to be taken seriously. The Maasai activist Agnes Pareyio campaigns against

5640-422: The city of Arusha. The summit was first explored between 1904 and 1915. As of 2012, about 300,000 people live in the region, and livestock farming is the most important economic activity, although tourism is increasingly important. Ol Doinyo Lengai is a symmetric cone that rises more than 1,800 metres (5,900 ft) above the surrounding rift valley. It has two craters on either side of the mountain summit, which

5734-665: The day they look like mudflows or oil and glow only during the night. They are highly fluid (reaching flow speeds of 1–5 metres per second (3.3–16.4 ft/s), making them the most liquid of all known lavas, and form short (few tens of meters) and thin (few centimeters thick) lava flows. More viscous flows containing silicic rocks have also been observed, for example during the 1993 eruption. Potential threats from Ol Doinyo Lengai eruptions are scarcely established. Threats from eruptions at Ol Doinyo Lengai include lahars , landslides , lava flows , pyroclastic flows , volcanic bombs , volcanic gas , and volcanic ash fall. Beginning in 2016,

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5828-545: The dichlorides have cadmium chloride structures. Upon treatment with a standard acid, fluoride salts convert to hydrogen fluoride and metal salts . With strong acids, it can be doubly protonated to give H 2 F . Oxidation of fluoride gives fluorine. Solutions of inorganic fluorides in water contain F and bifluoride HF 2 . Few inorganic fluorides are soluble in water without undergoing significant hydrolysis. In terms of its reactivity, fluoride differs significantly from chloride and other halides, and

5922-480: The ear. Among Maasai males, circumcision is practised as a ritual of transition from boyhood to manhood. Women are also circumcised (as described below in social organisation ). This belief and practice are not unique to the Maasai. In rural Kenya, a group of 95 children aged between six months and two years were examined in 1991/92. 87% were found to have undergone the removal of one or more deciduous canine tooth buds. In an older age group (3–7 years of age), 72% of

6016-441: The fertile lands between Mount Meru and Mount Kilimanjaro , and most of the fertile highlands near Ngorongoro in the 1940s. More land was taken to create wildlife reserves and national parks: Amboseli National Park , Nairobi National Park , Maasai Mara , Samburu National Reserve , Lake Nakuru National Park and Tsavo in Kenya; and Lake Manyara , Ngorongoro Conservation Area, Tarangire and Serengeti National Park in what

6110-441: The form of fluoride, is considered to be a micronutrient for human health, necessary to prevent dental cavities, and to promote healthy bone growth. The tea plant ( Camellia sinensis L.) is a known accumulator of fluorine compounds, released upon forming infusions such as the common beverage. The fluorine compounds decompose into products including fluoride ions. Fluoride is the most bioavailable form of fluorine, and as such, tea

6204-570: The haplogroup at high frequencies lived more than 13,000 years ago. The second most frequent paternal lineage among the Maasai was Haplogroup A3b2 , which is commonly found in Nilotic populations, such as the Alur ; it was observed in 27% of Maasai men. The third most frequently observed paternal DNA marker in the Maasai was E1b1a1-M2 (E-P1), which is very common in the Sub-Saharan region; it

6298-457: The hydrogen fluoride escapes. Fluoride is distinct in this regard among the halides. The identity of the solvent can have a dramatic effect on the equilibrium shifting it to the right-hand side, greatly increasing the rate of decomposition. Salts containing fluoride are numerous and adopt myriad structures. Typically the fluoride anion is surrounded by four or six cations, as is typical for other halides. Sodium fluoride and sodium chloride adopt

6392-812: The insolubility of the alkaline earth fluorides, e.g., CaF 2 . Concentrations in fresh water vary more significantly. Surface water such as rivers or lakes generally contains between 0.01 and 0.3 mg/L. Groundwater (well water) concentrations vary even more, depending on the presence of local fluoride-containing minerals. For example, natural levels of under 0.05 mg/L have been detected in parts of Canada but up to 8 mg/L in parts of China; in general levels rarely exceed 10 mg/litre Fluoride can be present in rain, with its concentration increasing significantly upon exposure to volcanic activity or atmospheric pollution derived from burning fossil fuels or other sorts of industry, particularly aluminium smelters . All vegetation contains some fluoride, which

6486-491: The lava flows and within lava tubes . Weathering on the silicic rocks has yielded zeoliths . The chemical composition of the erupted rocks is not steady, with an increase of silicic magma emplacement noted after 2007-2008, after an episode of increased spreading in the Gregory Rift. The carbonatitic magmas appear to form through the separation of carbon-rich phases; the original magma is variously interpreted to be either nephelinitic or silicic. The phonolites appear to have

6580-442: The more prized cattle. Although consumed as snacks, fruits constitute a major part of the food ingested by children and women looking after cattle as well as morans in the bush. Medicine The Maasai people traditionally used the environment when making their medicines, and many still do, due to the high cost of Western treatments. These medicines are derived from trees, shrubs, stems, roots, etc. These can then be used in

6674-503: The northern crater. During the middle 20th century, the crater was about 200 metres (660 ft) deep; subsequently, lava flows filled it, and by 1998, lava was overflowing its rims. The lava flows issue from cones within the crater and form lava ponds and lakes. Explosive eruptions are less common, having been reported in 1917, 1940, 1966, 1983 and 1993. Oversteepened slopes produce landslides , and erosion has cut gullies into volcanic deposits. Steam jets have also been observed. There

6768-486: The other is considered to be poor. All of the Maasai's needs for food are met by their cattle. They eat their meat, drink their milk daily, and drink their blood on occasion. Bulls, goats, and lambs are slaughtered for meat on special occasions and ceremonies. Though the Maasai's entire way of life has historically depended on their cattle, more recently with their cattle dwindling, the Maasai have grown dependent on food such as sorghum , rice, potatoes and cabbage (known to

6862-564: The past 3000 years and with the high frequency of a shared East African–specific mutation associated with lactose tolerance." Maasai display significant West-Eurasian admixture at roughly ~20%. This type of West-Eurasian ancestry reaches up to 40-50% among specific populations of the Horn of Africa , specifically among Amharas . Genetic data and archeologic evidence suggest that East African pastoralists received West Eurasian ancestry (~25%) through Afroasiatic-speaking groups from Northern Africa or

6956-404: The practice. The female rite of passage ritual has recently seen excision replaced in rare instances with a "cutting with words" ceremony involving singing and dancing in its place. However, despite changes to the law and education drives, the practice remains deeply ingrained, highly valued, and nearly universally practised by members of the culture. Upon reaching the age of 3 "moons", the child

7050-583: The procedure. The male ceremony refers to the excision of the prepuce (foreskin). In the male ceremony, the boy is expected to endure the operation in silence. Expressions of pain bring dishonour upon him, albeit only temporarily. Importantly, any exclamations or unexpected movements on the part of the boy can cause the elder to make a mistake in the delicate and tedious process, which can result in severe lifelong scarring, dysfunction, and pain. Young women also undergo female genital mutilation as part of an elaborate rite of passage ritual called "Emuatare,"

7144-488: The region, such as the Samburu . Most of the tested Maasai belonged to various macro-haplogroup L sub-clades, including L0 , L2 , L3 , L4 and L5 . Some maternal gene flow from North and Northeast Africa was also reported, particularly via the presence of mtDNA haplogroup M lineages in about 12.5% of the Maasai samples. The monotheistic Maasai worship a single deity called Enkai , Nkai , or Engai . Engai has

7238-675: The result of smallpox. This period coincided with drought. Rains failed in 1897 and 1898. The Austrian explorer Oscar Baumann travelled in Maasai lands between 1891 and 1893 and described the old Maasai settlement in the Ngorongoro Crater in the 1894 book Durch Massailand zur Nilquelle ("Through the lands of the Maasai to the source of the Nile"). By one estimate two-thirds of the Maasai died during this period. Maasai in Tanganyika (now mainland Tanzania) were displaced from

7332-549: The same as in the United States. For women ages 18 and older the AI is set at 2.9 mg/day (including pregnancy and lactation). For men, the value is 3.4 mg/day. For children ages 1–17 years, the AIs increase with age from 0.6 to 3.2 mg/day. These AIs are comparable to the U.S. AIs. The EFSA reviewed safety evidence and set an adult UL at 7.0 mg/day (lower for children). For U.S. food and dietary supplement labeling purposes,

7426-451: The same structure. For compounds containing more than one fluoride per cation, the structures often deviate from those of the chlorides, as illustrated by the main fluoride mineral fluorite (CaF 2 ) where the Ca ions are surrounded by eight F centers. In CaCl 2 , each Ca ion is surrounded by six Cl centers. The difluorides of the transition metals often adopt the rutile structure whereas

7520-462: The slopes of the volcano, which have large fractures on the western flank. There are parasitic vents on Ol Doinyo Lengai's flanks, such as Kirurum Crater on the western, the Nasira cones on the northern, Dorobo crater on the northeastern, and Oltatwa Crater on the eastern flank. There are deposits of past debris avalanches around the volcano, especially on its northern flank; one such event has left

7614-464: The start of volcanic eruptions at Ol Doinyo Lengai range from more than 500,000 to 22,000 years ago. It formed in two stages, Lengai I consisting of phonolite that forms about 60% of the volume of Ol Doinyo Lengai and crops out in its southern part, and Lengai II formed by nephelinitic rocks; growth of the volcanic cone was complete about 15,000 years ago, when the Naisiusiu Beds were emplaced in

7708-423: The stomach, sometimes so severely as to cause ulcers. Slow-release and enteric -coated versions of sodium fluoride do not have gastric side effects in any significant way, and have milder and less frequent complications in the bones. In the lower doses used for water fluoridation , the only clear adverse effect is dental fluorosis , which can alter the appearance of children's teeth during tooth development ; this

7802-521: The study's authors, the Maasai "have maintained their culture in the face of extensive genetic introgression". Tishkoff et al. also indicate that: "Many Nilo-Saharan-speaking populations in East Africa, such as the Maasai, show multiple cluster assignments from the Nilo-Saharan [...] and Cushitic [...] AACs, in accord with linguistic evidence of repeated Nilotic assimilation of Cushites over

7896-418: The valid IUPAC name, is determined according to the additive nomenclature. However, the name fluoride is also used in compositional IUPAC nomenclature which does not take the nature of bonding involved into account. Fluoride is also used non-systematically, to describe compounds which release fluoride upon dissolving. Hydrogen fluoride is itself an example of a non-systematic name of this nature. However, it

7990-430: The values are smaller, ranging from 0.7 mg/d to 2.2 mg/d for infants. Water and food sources of fluoride include community water fluoridation, seafood, tea, and gelatin. Soluble fluoride salts, of which sodium fluoride is the most common, are toxic, and have resulted in both accidental and self-inflicted deaths from acute poisoning . The lethal dose for most adult humans is estimated at 5 to 10 g (which

8084-637: The volcano and to increased awareness of the threat formed by the volcano. Wild animals such as flamingos were also impacted by the eruption. The eruption was preceded in July by seismic activity, which was frequently mistaken for renewed eruptions, and the intrusion of a dyke less than 20 kilometres (12 mi) from Ol Doinyo Lengai. Lavas erupted by Ol Doinyo Lengai initially have brown or black colors, but within days to hours become white like snow. The lavas of Ol Doinyo Lengai have temperatures of 540–593 °C (1,004–1,099 °F); they are so cold that during

8178-692: The volcano is being monitored by a seismometer and GNSS stations. Vegetation in the area consists mostly of grassland, which reaches an elevation of 1,750 metres (5,740 ft) above sea level. Volcanic ash from Ol Doinyo Lengai influences the surrounding landscape, favoring the growth of nutrient-rich plants. Precipitation falls during two wet seasons in March–May and October–December. Maasai people Modern ethnicities Diaspora Performing arts Government agencies Television Radio Newspapers The Maasai ( / ˈ m ɑː s aɪ , m ɑː ˈ s aɪ / ; Swahili : Wamasai ) are

8272-432: The volcano settled back into the effusion of lava flows; a cinder cone formed in the northern crater during the eruption. Aerosol clouds from the eruption extended over east Africa. The 2007 eruptions forced the evacuation of three villages and disturbed air travel in the touristically important area; livestock fatalities and injuries to people led to requests that the government of Tanzania enact access restrictions to

8366-469: Was a function of personality rather than position. Many Maasai have also adopted Christianity or Islam . The Maasai produce intricate jewellery and sell these items to tourists. Educating Maasai women to use clinics and hospitals during pregnancy has enabled more infants to survive. The exception is found in extremely remote areas. A corpse rejected by scavengers is seen as having something wrong with it, and liable to cause social disgrace; therefore, it

8460-459: Was a report of a concentration of 800 Maasai warriors on the move in what is now Kenya. In 1857, after having depopulated the "Wakuafi wilderness" in what is now southeastern Kenya, Maasai warriors threatened Mombasa on the Kenyan coast. Because of this migration, the Maasai are the southernmost Nilotic speakers. The period of expansion was followed by the Maasai "Emutai" of 1883–1902. This period

8554-423: Was found in 12% of the Maasai samples. Haplogroup B-M60 was also observed in 8% of the studied Maasai, which is also found in 30% (16/53) of Southern Sudanese Nilotes. According to an mtDNA study by Castri et al. (2008), which tested Maasai individuals in Kenya, the maternal lineages found among the Maasai are quite diverse but similar in overall frequency to that observed in other Nilo-Hamitic populations from

8648-399: Was marked by epidemics of contagious bovine pleuropneumonia , rinderpest (see 1890s African rinderpest epizootic ), and smallpox . The estimate first put forward by a German lieutenant in what was then northwest Tanganyika , was that 90% of cattle and half of wild animals perished from rinderpest. German doctors in the same area claimed that "every second" African had a pock-marked face as

8742-463: Was synthesized that is the closest approximation of a thermodynamically stable and structurally characterized example of a "naked" fluoride source in an aprotic solvent (acetonitrile). The sterically demanding imidazolium cation stabilizes the discrete anions and protects them from polymerization. At physiological pHs, hydrogen fluoride is usually fully ionised to fluoride. In biochemistry , fluoride and hydrogen fluoride are equivalent. Fluorine, in

8836-486: Was used to fluoridate water; hexafluorosilicic acid (H 2 SiF 6 ) and its salt sodium hexafluorosilicate (Na 2 SiF 6 ) are more commonly used additives, especially in the United States. The fluoridation of water is known to prevent tooth decay and is considered by the U.S. Centers for Disease Control and Prevention to be "one of 10 great public health achievements of the 20th century". In some countries where large, centralized water systems are uncommon, fluoride

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