South Africa
South Africa the Republic of South Africa, is the southernmost country in Africa. It is bounded to the south by 2,798 kilometres of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans. South Africa is the largest country in Southern Africa and the 25th-largest country in the world by land area and, with over 57 million people, is the world's 24th-most populous nation, it is the southernmost country on the mainland of the Eastern Hemisphere. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different African languages, nine of which have official status; the remaining population consists of Africa's largest communities of European and multiracial ancestry. South Africa is a multiethnic society encompassing a wide variety of cultures and religions, its pluralistic makeup is reflected in the constitution's recognition of 11 official languages, the fourth highest number in the world. Two of these languages are of European origin: Afrikaans developed from Dutch and serves as the first language of most coloured and white South Africans.
The country is one of the few in Africa never to have had a coup d'état, regular elections have been held for a century. However, the vast majority of black South Africans were not enfranchised until 1994. During the 20th century, the black majority sought to recover its rights from the dominant white minority, with this struggle playing a large role in the country's recent history and politics; the National Party imposed apartheid in 1948. After a long and sometimes violent struggle by the African National Congress and other anti-apartheid activists both inside and outside the country, the repeal of discriminatory laws began in 1990. Since 1994, all ethnic and linguistic groups have held political representation in the country's liberal democracy, which comprises a parliamentary republic and nine provinces. South Africa is referred to as the "rainbow nation" to describe the country's multicultural diversity in the wake of apartheid; the World Bank classifies South Africa as an upper-middle-income economy, a newly industrialised country.
Its economy is the second-largest in Africa, the 34th-largest in the world. In terms of purchasing power parity, South Africa has the seventh-highest per capita income in Africa; however and inequality remain widespread, with about a quarter of the population unemployed and living on less than US$1.25 a day. South Africa has been identified as a middle power in international affairs, maintains significant regional influence; the name "South Africa" is derived from the country's geographic location at the southern tip of Africa. Upon formation, the country was named the Union of South Africa in English, reflecting its origin from the unification of four separate British colonies. Since 1961, the long form name in English has been the "Republic of South Africa". In Dutch, the country was named Republiek van Zuid-Afrika, replaced in 1983 by the Afrikaans Republiek van Suid-Afrika. Since 1994, the Republic has had an official name in each of its 11 official languages. Mzansi, derived from the Xhosa noun umzantsi meaning "south", is a colloquial name for South Africa, while some Pan-Africanist political parties prefer the term "Azania".
South Africa contains human-fossil sites in the world. Archaeologists have recovered extensive fossil remains from a series of caves in Gauteng Province; the area, a UNESCO World Heritage site, has been branded "the Cradle of Humankind". The sites include one of the richest sites for hominin fossils in the world. Other sites include Gondolin Cave Kromdraai, Coopers Cave and Malapa. Raymond Dart identified the first hominin fossil discovered in Africa, the Taung Child in 1924. Further hominin remains have come from the sites of Makapansgat in Limpopo Province and Florisbad in the Free State Province, Border Cave in KwaZulu-Natal Province, Klasies River Mouth in Eastern Cape Province and Pinnacle Point and Die Kelders Cave in Western Cape Province; these finds suggest that various hominid species existed in South Africa from about three million years ago, starting with Australopithecus africanus. There followed species including Australopithecus sediba, Homo ergaster, Homo erectus, Homo rhodesiensis, Homo helmei, Homo naledi and modern humans.
Modern humans have inhabited Southern Africa for at least 170,000 years. Various researchers have located pebble tools within the Vaal River valley. Settlements of Bantu-speaking peoples, who were iron-using agriculturists and herdsmen, were present south of the Limpopo River by the 4th or 5th century CE, they displaced and absorbed the original Khoisan speakers, the Khoikhoi and San peoples. The Bantu moved south; the earliest ironworks in modern-day KwaZulu-Natal Province are believed to date from around 1050. The southernmost group was the Xhosa people, whose language incorporates certain linguistic traits from the earlier Khoisan people; the Xhosa reached the Great Fish River, in today's Eastern Cape Province. As they migrated, these larger Iron Age populations
Cattle
Cattle—colloquially cows—are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, are most classified collectively as Bos taurus. Cattle are raised as livestock for meat, for milk, for hides, which are used to make leather, they are used as riding animals and draft animals. Another product of cattle is dung, which can be used to create fuel. In some regions, such as parts of India, cattle have significant religious meaning. Cattle small breeds such as the Miniature Zebu, are kept as pets. Around 10,500 years ago, cattle were domesticated from as few as 80 progenitors in central Anatolia, the Levant and Western Iran. According to an estimate from 2011, there are 1.4 billion cattle in the world. In 2009, cattle became one of the first livestock animals to have a mapped genome; some consider cattle the oldest form of wealth, cattle raiding one of the earliest forms of theft. Cattle were identified as three separate species: Bos taurus, the European or "taurine" cattle.
The aurochs is ancestral to both taurine cattle. These have been reclassified as one species, Bos taurus, with three subspecies: Bos taurus primigenius, Bos taurus indicus, Bos taurus taurus. Complicating the matter is the ability of cattle to interbreed with other related species. Hybrid individuals and breeds exist, not only between taurine cattle and zebu, but between one or both of these and some other members of the genus Bos – yaks and gaur. Hybrids such as the beefalo breed can occur between taurine cattle and either species of bison, leading some authors to consider them part of the genus Bos, as well; the hybrid origin of some types may not be obvious – for example, genetic testing of the Dwarf Lulu breed, the only taurine-type cattle in Nepal, found them to be a mix of taurine cattle and yak. However, cattle cannot be hybridized with more distantly related bovines such as water buffalo or African buffalo; the aurochs ranged throughout Europe, North Africa, much of Asia. In historical times, its range became restricted to Europe, the last known individual died in Mazovia, Poland, in about 1627.
Breeders have attempted to recreate cattle of similar appearance to aurochs by crossing traditional types of domesticated cattle, creating the Heck cattle breed. The noun cattle encompasses both sexes; the singular, technically means the female, the male being bull. The plural form cows is sometimes used colloquially to refer to both sexes collectively, as e.g. in a herd, but that usage can be misleading as the speaker's intent may indeed be just the females. The bovine species per se is dimorphic. Cattle did not originate as the term for bovine animals, it was borrowed from Anglo-Norman catel, itself from medieval Latin capitale'principal sum of money, capital', itself derived in turn from Latin caput'head'. Cattle meant movable personal property livestock of any kind, as opposed to real property; the word is a variant of chattel and related to capital in the economic sense. The term replaced earlier Old English feoh ` property', which survives today as fee; the word "cow" came via Anglo-Saxon cū, from Common Indo-European gʷōus = "a bovine animal", compare Persian: gâv, Sanskrit: go-, Welsh: buwch.
The plural cȳ became ki or kie in Middle English, an additional plural ending was added, giving kine, but kies and others. This is the origin of the now archaic English plural, "kine"; the Scots language singular is coo or cou, the plural is "kye". In older English sources such as the King James Version of the Bible, "cattle" refers to livestock, as opposed to "deer" which refers to wildlife. "Wild cattle" may refer to undomesticated species of the genus Bos. Today, when used without any other qualifier, the modern meaning of "cattle" is restricted to domesticated bovines. In general, the same words are used in different parts of the world, but with minor differences in the definitions; the terminology described here contrasts the differences in definition between the United Kingdom and other British-influenced parts of the world such as Canada, New Zealand and the United States. An "intact" adult male is called a bull. A wild, unmarked bull is known as a micky in Australia. An unbranded bovine of either sex is called a maverick in the Canada.
An adult female that has had a calf is a cow. A young female before she has had a calf of her own and is under three years of age is called a heifer. A young female that has had only one calf is called a first-calf heifer. Young cattle of both sexes are called calves until they are weaned weaners until they are a year old in some areas. After that, they are referred to as stirks if between one and two years of age. A castrated male is called a steer in the United States.
Happy Valley set
The Happy Valley set was a group of hedonistic British and Anglo-Irish aristocrats and adventurers who settled in the "Happy Valley" region of the Wanjohi Valley, near the Aberdare mountain range, in colonial Kenya and Uganda between the 1920s and the 1940s. In the 1930s, the group became infamous for its decadent lifestyles and exploits, following reports of drug use and sexual promiscuity; the area around Naivasha was one of the first to be settled in Kenya by white people and was one of the main hunting grounds of the'set'. The colonial town of Nyeri, Kenya, to the east of the Aberdare Range, was the centre of Happy Valley settlers. In recent years, descendants of the Happy Valley set have been appearing in the news the legal troubles of Tom Cholmondeley, the great-grandson of Lord Delamere; some of the notable members of the Happy Valley set were: The 3rd Baron Delamere and his son and heir The 4th Baron Delamere. According to Ulf Aschen, "Witty, well-bred, well read, Happy Valleyites were relentless in their pursuit to be amused, more attaining this through drink and sex."The height of the Happy Valley set's influence was in the late 1920s.
The recession sparked by the 1929 Wall Street stock market crash decreased the number of new arrivals to the Colony of Kenya and the influx of capital. By 1939 Kenya had a white community of 21,000 people; the area around Naivasha was one of the first to be settled by white people and one of the hunting grounds of the hedonistic Happy Valley set. The area includes Thomson's Falls. Geoffrey Buxton, the first colonial farmer in the area, had moved up from the arid Rift Valley with its meagre rivers and a relentless dusty wind that gave Gilgil its name, and so, after finding his ideal farming country, he called this new haven'Happy Valley'. Some members of the Happy Valley set lived in Gilgil, just north of Lake Elementaita; the colonial town of Nyeri in Central Province, to the east of the Aberdare Range, was the centre of Happy Valley settlers. The town had the atmosphere of a sleepy English village, an impression fostered by the cool air and morning mists. Outside Nyeri is the Outspan Hotel, a colonial landmark which became a place of pilgrimage for the world's Scouts.
A small cottage on the hotel grounds was the final home of Lord Baden-Powell and his wife, founders of the Scouting movement, he is buried outside Nyeri. The cottage has a small museum dedicated to Baden-Powell's memory; the antics of the Happy Valley set were highlighted in books and films such as White Mischief, which dramatised the trial of Jock Delves Broughton for the murder of Josslyn Hay, 22nd Earl of Erroll. A biography of Idina Sackville, The Bolter, by Frances Osborne, includes stories of the origins of the Happy Valley set and features many of its key characters. Sackville was married to Lord Erroll for several years, they had a child together; the 1999 UK television mini-series Heat of the Sun looks at the fictional lives and crimes of Happy Valley dwellers. Although there is no actual definition of what constitutes a member of the Happy Valley set, it is agreed by writers that it refers to white colonials located in or around the area of the Wanjohi Valley, who were infamous during the 1920s–1940s period for a number of scandals revolving around infidelity and drug/alcohol abuse.
Some of the most notable members of that clique are the following: One of the first British settlers in East Africa, Hugh Cholmondeley, 3rd Baron Delamere, K. C. M. G. is credited with helping form the Happy Valley set. Lord Delamere first travelled to East Africa in 1891 for lion hunting and returned yearly to resume the hunt. In 1894, he was mauled by an attacking lion; as a result, he limped for the rest of his life. He is credited for coining the term "white hunter". In 1896, he moved to Africa and settled in Kenya. In 1906, he acquired a large farm, the Soysambu Ranch, which would rise to 200,000 acres. Lord Delamere is considered to have contributed to the development of Kenyan agriculture, he became the unofficial leader of the white community in Kenya. He was active in recruiting settlers to East Africa, admired the culture of the local Maasai. There is a story of Delamere's riding his horse into the dining room of Nairobi's Norfolk Hotel and jumping over the tables, he was known to knock golf balls onto the roof of the Muthaiga Country Club, the pink stucco gathering-place for Nairobi's white élite, climb up to retrieve them.
At the outbreak of WWI, Delamere was placed in charge of intelligence on the Maasai border, monitoring the movements of German units in present-day Tanzania. He married Lady Charles Markham in 1928, he died in 1931. A Scottish peer and notorious philanderer, Josslyn Victor Hay, 22nd Earl of Erroll abandoned his diplomatic career in Great Britain and scandalised society when he eloped with a married woman, Lady Idina Sackville; the couple were married in 1923 and moved to Kenya in 1924. They became the unofficial'king and queen' of'Happy Valley' and their home, became a centre of social life, notorious for its orgies. Idina, Countess of Erroll, divorced him in 1929. Lord Erroll was having an affair with married woman Molly Ramsay-Hill; the couple eloped. When Ramsay-Hi
Coffee
Coffee is a brewed drink prepared from roasted coffee beans, the seeds of berries from certain Coffea species. The genus Coffea is native to tropical Africa and Madagascar, the Comoros, Réunion in the Indian Ocean. Coffee plants are now cultivated in over 70 countries in the equatorial regions of the Americas, Southeast Asia, Indian subcontinent, Africa; the two most grown are C. arabica and C. robusta. Once ripe, coffee berries are picked and dried. Dried coffee seeds are roasted to varying degrees, depending on the desired flavor. Roasted beans are ground and brewed with near-boiling water to produce the beverage known as coffee. Coffee is darkly colored, bitter acidic and has a stimulating effect in humans due to its caffeine content, it is one of the most popular drinks in the world, it can be prepared and presented in a variety of ways. It is served hot, although iced coffee is a popular alternative. Clinical studies indicate that moderate coffee consumption is benign or mildly beneficial in healthy adults, with continuing research on whether long-term consumption lowers the risk of some diseases, although those long-term studies are of poor quality.
The earliest credible evidence of coffee-drinking appears in modern-day Yemen in southern Arabia in the middle of the 15th century in Sufi shrines. It was here in Arabia that coffee seeds were first roasted and brewed in a similar way to how it is now prepared, but the coffee seeds had to be first exported from East Africa to Yemen, as the Coffea arabica plant is thought to have been indigenous to the former. The Yemenis began to cultivate the seed. By the 16th century, the drink had reached Persia and North Africa. From there, it spread to the rest of the world; as of 2016, Brazil was the leading grower of producing one-third of the world total. Coffee is a major export commodity, it is one of the most valuable commodities exported by developing countries. Green, unroasted coffee is one of the most traded agricultural commodities in the world; some controversy has been associated with coffee cultivation and the way developed countries trade with developing nations, as well as the impact on the environment with regards to the clearing of land for coffee-growing and water use.
The markets for fair trade and organic coffee are expanding, notably in the USA. The word coffee appears to have derived from the name of the region where coffee beans were first used by a herder in the 6th or 9th century: kaffa derived from Kaffa Province, the name of the region in ancient Abyssinia; the word "coffee" entered the English language in 1582 via the Dutch koffie, borrowed from the Ottoman Turkish kahve, borrowed in turn from the Arabic qahwah. The Arabic word qahwah was traditionally held to refer to a type of wine whose etymology is given by Arab lexicographers as deriving from the verb qahiya, "to lack hunger", in reference to the drink's reputation as an appetite suppressant, it has been proposed that the source may be the Proto-Central Semitic root q-h-h meaning "dark". The term "coffee pot" dates from 1705; the expression "coffee break" was first attested in 1952. According to legend, ancestors of today's Oromo people in a region of Kaffa in Ethiopia were believed to have been the first to recognize the energizing effect of the coffee plant.
However, there is no direct evidence, found earlier than the 15th century indicating where in Africa coffee first grew or who among the native populations might have used it as a stimulant. The story of Kaldi, the 9th-century Ethiopian goatherd who discovered coffee when he noticed how excited his goats became after eating the beans from a coffee plant, did not appear in writing until 1671 and is apocryphal. Other accounts attribute the discovery of coffee to Sheikh Omar. According to an ancient chronicle, known for his ability to cure the sick through prayer, was once exiled from Mocha in Yemen to a desert cave near Ousab. Starving, Omar found them to be bitter, he tried roasting the seeds to improve the flavor. He tried boiling them to soften the seed, which resulted in a fragrant brown liquid. Upon drinking the liquid Omar was sustained for days; as stories of this "miracle drug" reached Mocha, Omar was made a saint. The earliest credible evidence of coffee-drinking or knowledge of the coffee tree appears in the middle of the 15th century in the accounts of Ahmed al-Ghaffar in Yemen.
It was here in Arabia that coffee seeds were first roasted and brewed, in a similar way to how it is prepared now. Coffee was used by Sufi circles to stay awake for their religious rituals. Accounts differ on the origin of the coffee plant prior to its appearance in Yemen. From Ethiopia, coffee could have been introduced to Yemen via trade across the Red Sea. One account credits Muhammad Ibn Sa'd for bringing the beverage to Aden from the African coast. Other early accounts say Ali ben Omar of the Shadhili Sufi order was the first to introduce coffee to Arabia. According to al Shardi, Ali ben Omar may have encountered coffee during his stay with the Adal king Sadadin's companions in 1401. Famous 16th-century Islamic scholar Ibn Hajar al-Haytami notes in his
Pyrethrum
Pyrethrum was a genus of several Old World plants now classified as Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants included in the genus Pyrethrum. Pyrethrum is the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium and Chrysanthemum coccineum; some members of the genus Chrysanthemum, such as the following two, are placed in the genus Tanacetum instead by some botanists. Both genera are members of Asteraceae, they are all perennial plants with white petals. Tanacetum cinerariifolium is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans, it looks more like the common daisy. Its flowers white with yellow centers, grow from numerous rigid stems. Plants grow to 45 to 100 cm in height; the plant is economically important as a natural source of insecticide. The flowers are pulverized and the active components, called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin.
This is applied as a powder. Pyrethrins attack the nervous systems of all insects, inhibit female mosquitoes from biting; when present in amounts less than those fatal to insects, they still appear to have an insect repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides and are not persistent, being biodegradable and decompose on exposure to light, they are considered to be amongst the safest insecticides for use around food. Kenya produced 90% of the world's pyrethrum in 1998, called py for short. Production in Tanzania and Ecuador is significant; the world's major producer is Tasmania, Australia. C. coccineum, the Persian chrysanthemum, is a perennial plant native to Caucasus and looks somewhat like a daisy. It produces large pink or red flowers; the leaves resemble those of ferns, the plant grows to between 30 and 60 cm in height. The flowering period is June to July in temperate climates. C. coccineum contains insecticidal pyrethrum substances, but it is a poor source compared to C. cinerariifolium.
Other species, such as C. balsamita and C. marshalli contain insecticidal substances, but are less effective than the two species mentioned above. Pyrethrum has been used for centuries as an insecticide, as a lice remedy in the Middle East, it was sold worldwide under the brand Zacherlin by Austrian industrialist J. Zacherl, it is one of the most used non-synthetic insecticides allowed in certified organic agriculture. The flowers should be dried and crushed and mixed with water. Pyrethroids are synthetic insecticides based on natural pyrethrum. A common formulation of pyrethrin is in preparations containing the synthetic chemical piperonyl butoxide: this has the effect of enhancing the toxicity to insects and speeding the effects when compared with pyrethrins used alone; these formulations are known as synergized pyrethrins. Rat and rabbit LD50 levels for pyrethrum are high, with doses in some cases of about 1% of the animal's body weight required to cause significant mortality similar to levels in synthetic pyrethroids.
Pyrethrum should be handled with the same caution as synthetic insecticides. People can be exposed to pyrethrum as a mixture of cinerin and pyrethrin in the workplace by breathing it in, getting it in the eyes or on the skin, or swallowing it; the Occupational Safety and Health Administration has set the legal limit for pyrethrum exposure in the workplace as 5 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health has set a Recommended exposure limit of 5 mg/m3 over an 8-hour workday. At levels of 5000 mg/m3, pyrethrum is dangerous to life and health. People exposed to pyrethrum may experience symptoms including pruritus, papules, rhinorrhea and asthma. People using pyrethrum should wear safety equipment, it is a chemical. Because chrysanthemums contain pyrethrums, they are used as companion plants to repel pest insects from nearby crops and ornamental plants, they are thought to repel aphids, bed bugs, spider mites, harlequin bugs, ticks and imported cabbage worms, among others, in gardens and farms.
For example, they are planted among broccoli plants for protection from several common insect pests. Common names for Chrysanthemum cinerariifolium include: Pyrethrum Pyrethrum daisy Dalmatian pyrethrum Dalmatian chrysanthemum Dalmatian insect flower Dalmatian pellitory Big daisyCommon names for Chrysanthemum coccineum include: Pyrethrum Pyrethrum daisy Painted daisy Persian chrysanthemum Persian insect flower Persian pellitory Caucasian insect powder plant Chrysanthemum List of companion plants Category: Plant toxin insecticides Permethrin Pyrethrin National Pesticide Information Center: Pyrethrins and Pyrethroids Fact Sheet CDC - NIOSH Pocket Guide to Chemical Hazards EXTOXNET: Pyrethrins and Pyrethroids "What is Pyrethrum?" "International Center for Pyrethrum Research"
Sisal
Sisal, with the botanical name Agave sisalana, is a species of Agave native to southern Mexico but cultivated and naturalized in many other countries. It yields a stiff fibre used in making various products; the term sisal may refer depending on the context. It is sometimes referred to as "sisal hemp", because for centuries hemp was a major source for fibre, other fibre sources were named after it; the sisal fibre is traditionally used for rope and twine, has many other uses, including paper, footwear, bags and dartboards. The native origin of Agave sisalana is uncertain. Traditionally it was deemed to be a native of the Yucatán Peninsula, but there are no records of botanical collections from there, they were shipped from the Spanish colonial port of Sisal in Yucatán. The Yucatán plantations now cultivate henequen. H. S. Gentry hypothesized a Chiapas origin, on the strength of traditional local usage. Evidence of an indigenous cottage industry there suggests it as the original habitat location as a cross of Agave angustifolia and Agave kewensis.
The species is now naturalized in other parts of Mexico, as well as in Spain, Morocco, the Canary Islands, Cape Verde, many parts of Africa, Madagascar, Réunion, China, the Ryukyu Islands, Pakistan, Burma, Thailand, the Solomon Islands, Polynesia, Fiji, Florida, Central America and the West Indies. Sisal plants, Agave sisalana, consist of a rosette of sword-shaped leaves about 1.5–2 metres tall. Young leaves may lose them as they mature; the sisal plant has a 7–10 year life-span and produces 200–250 commercially usable leaves. Each leaf contains an average of around 1000 fibres; the fibres account for only about 4% of the plant by weight. Sisal is considered a plant of the tropics and subtropics, since production benefits from temperatures above 25 degrees Celsius and sunshine. Sisal was used by the Aztecs and the Mayans to make crude fabrics and paper. In the 19th century, sisal cultivation spread to Florida, the Caribbean islands, Brazil, as well as to countries in Africa, notably Tanzania and Kenya, Asia.
In Cuba its cultivation was introduced by Fernando Heydrich in Matanzas. The first commercial plantings in Brazil were made in the late 1930s and the first sisal fibre exports from there were made in 1948, it was not until the 1960s that Brazilian production accelerated and the first of many spinning mills was established. Today Brazil is the major world producer of sisal. There are both negative environmental impacts from sisal growing. Propagation of sisal is by using bulbils produced from buds in the flower stalk or by suckers growing around the base of the plant, which are grown in nursery fields until large enough to be transplanted to their final position; these methods offer no potential for genetic improvement. In vitro multiplication of selected genetic material using meristematic tissue culture offers considerable potential for the development of improved genetic material. Fibre is extracted by a process known as decortication, where leaves are crushed and brushed away by a rotating wheel set with blunt knives, so that only fibres remain.
Alternatively, in East Africa, where production is on large estates, the leaves are transported to a central decortication plant, where water is used to wash away the waste parts of the leaf. The fibre is dried and baled for export. Proper drying is important as fibre quality depends on moisture content. Artificial drying has been found to result in better grades of fibre than sun drying, but is not always feasible in the developing countries where sisal is produced. In the drier climate of north-east Brazil, sisal is grown by smallholders and the fibre is extracted by teams using portable raspadors which do not use water. Fibre is subsequently cleaned by brushing. Dry fibres are machine combed and sorted into various grades on the basis of the previous in-field separation of leaves into size groups. Sisal farming caused environmental degradation, because sisal plantations replaced native forests, but is still considered less damaging than many types of farming. No chemical fertilizers are used in sisal production, although herbicides are used this impact may be eliminated, since most weeding is done by hand.
The effluent from the decortication process causes serious pollution when it is allowed to flow into watercourses. In Tanzania there are plans to use the waste as bio-fuel. Sisal is considered to be an invasive species in Florida. Traditionally, sisal has been the leading material for agricultural twine because of its strength, ability to stretch, affinity for certain dyestuffs, resistance to deterioration in saltwater; the importance of this traditional use is diminishing with competition from polypropylene and the development of other haymaking techniques, while new higher-valued sisal products have been developed. Apart from ropes and general cordage, sisal is used in low-cost and specialty paper, buffing cloth, geotextiles, carpets, wire rope cores, Macramé. Sisal has been utilized as an environmentally friendly strengthening agent to replace asbestos and fibreglass in composite materials in various uses including the automobile industry; the lower-grade fibre is processed by the paper industry because of its high content of cellulose and hemicelluloses.
The medium-grade fibre is used in the cor
Locust
Locusts are certain species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are solitary, but under certain circumstances they become more abundant and change their behaviour and habits, becoming gregarious. No taxonomic distinction is made between grasshopper species. In the solitary phase, these grasshoppers are innocuous, their numbers are low, they do not pose a major economic threat to agriculture. However, under suitable conditions of drought followed by rapid vegetation growth, serotonin in their brains triggers a dramatic set of changes: they start to breed abundantly, becoming gregarious and nomadic when their populations become dense enough, they form bands of wingless nymphs which become swarms of winged adults. Both the bands and the swarms move around and strip fields and cause damage to crops; the adults are powerful fliers. Locusts have formed plagues since prehistory; the ancient Egyptians carved them on their tombs and the insects are mentioned in the Iliad, the Bible and the Quran.
Swarms have been a contributory cause of famines and human migrations. More changes in agricultural practices and better surveillance of locations where swarms tend to originate, have meant that control measures can be used at an early stage; the traditional means of control are based on the use of insecticides from the ground or the air, but other methods using biological control are proving effective. Swarming behaviour decreased in the 20th century, but despite modern surveillance and control methods, the potential for swarms to form is still present, when suitable climatic conditions occur and vigilance lapses, plagues can still occur. Locusts are large insects and convenient for use in research and the study of zoology in the classroom, they are edible insects. The word "locust" is derived from the Latin Vulgate locusta. Locusts are the swarming phase of certain species of short-horned grasshoppers in the family Acrididae; these insects are solitary, but under certain circumstances become more abundant and change their behaviour and habits, becoming gregarious.
No taxonomic distinction is made between grasshopper species. In English, the term "locust" is used for grasshopper species that change morphologically and behaviourally on crowding, forming swarms that develop from bands of immature stages called hoppers; these changes are examples of phase polymorphism. He made his discoveries during his studies of the Migratory locust in Caucasus, whose solitary and gregarious phases had been thought to be separate species, he designated the two phases as gregaria. These are referred to as statary and migratory morphs, though speaking, their swarms are nomadic rather than migratory. Charles Valentine Riley and Norman Criddle were involved in achieving the understanding and control of locusts. Swarming behaviour is a response to overcrowding. Increased tactile stimulation of the hind legs causes an increase in levels of serotonin; this causes the locust to change colour, eat much more, breed much more easily. The transformation of the locust to the swarming form is induced by several contacts per minute over a four-hour period.
A large swarm can consist of billions of locusts spread out over an area of thousands of square kilometres, with a population of up to 80 million per square kilometre. When desert locusts meet, their nervous systems release serotonin, which causes them to become mutually attracted, a prerequisite for swarming; the initial bands of gregarious hoppers are known as "outbreaks", when these join together into larger groups, the event is known as an "upsurge". Continuing agglomerations of upsurges on a regional level originating from a number of separate breeding locations are known as "plagues". During outbreaks and the early stages of upsurges, only part of the locust population becomes gregarious, with scattered bands of hoppers spread out over a large area; as time goes by, the insects become more cohesive and the bands become concentrated in a smaller area. In the desert locust plague in Africa, the Middle East, Asia that lasted from 1966 to 1969, the number of locusts increased from two to 30 billion over two generations, but the area covered decreased from over 100,000 square kilometres to 5,000 square kilometres.
One of the greatest differences between the solitary and gregarious phases is behavioural. The gregaria nymphs are attracted to this being seen as early as the second instar, they soon form bands of many thousands of individuals. These groups behave like cohesive units and move across the landscape downhill, but making their way around barriers and merging with other bands; the attraction between the insects seems to be visual, but involves olfactory cues, the band seem to navigate using the sun. They pause to feed at intervals before resuming their march, may cover tens of kilometres over a few weeks. Differences in morphology and development are seen. In the desert locust and the migratory locust, for example, the gregaria nymphs become darker with st
