Africans

The features created by crustal movements may be mountain chains, like the Himalayas, where collision of continents causes extensive compression. Conversely, the depressions of the Red Sea and East African Rift Basin are formed by extensional plate movements. Both type of movements form large scale depressions into which sediments from the surrounding elevated areas ( highs ) are transported. These depressions are termed sedimentary basins (Fig. 2.3). The basin fill can attain a thickness of several kilometres. 

Gr. technetos, artificial) Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Eawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial material have been made. Finally in 1962, technetium-99 was isolated and identified in African pitchblende (a uranium rich ore) in extremely minute quantities as a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. 

Physostigmme an alkaloid obtained from a West African plant is used in the treatment of glaucoma Treatment of physostigmme with methyl iodide gives a quaternary ammonium salt What IS the structure of this salt" ... 

Cubitene is a diterpene present in the defense secretion of a species of African termite What unusual feature charactenzes the joining of isoprene units in cubitene" ... 

Rice is grown in more than 100 countries and on every continent except Antarctica. In the world economy rice is an extremely important food, second only to wheat in total world production, and its yield per hectare exceeds that of wheat (57). Rice is the main staple food for more than half of the world s population and it accounts for one-third to one-half of the daily caloric intake in many Asian countries. It is also the major source of protein for the masses of Asian people. In many African and South American countries rice is rapidly becoming the staple food for much of the population. 

R. P. King, ed., Trinciples of Flotation South African Institute of Mining and Metallurgy, Johaimesburg, South Africa, 1982. 

Fluoroacetic acid [144-49-OJ, FCH2COOH, is noted for its high, toxicity to animals, including humans. It is sold in the form of its sodium salt as a rodenticide and general mammalian pest control agent. The acid has mp, 33°C bp, 165°C heat of combustion, —715.8 kJ/mol( —171.08 kcal/mol) (1) enthalpy of vaporization, 83.89 kJ /mol (20.05 kcal/mol) (2). Some thermodynamic and transport properties of its aqueous solutions have been pubHshed (3), as has the molecular stmcture of the acid as deterrnined by microwave spectroscopy (4). Although first prepared in 1896 (5), its unusual toxicity was not pubhshed until 50 years later (6). The acid is the toxic constituent of a South African plant Dichapetalum i mosum better known as gifirlaar (7). At least 24 other poisonous plant species are known to contain it (8). 

Gum Arabic. Gum arable [9000-01-5] is a dried exudate from a species of the acacia tree found in various tropical and semitropical areas of the world. Most of the commercial gum comes from a single species, Jicacia Senegal. The largest producers are the RepubHc of Sudan and several other West African countries, with over 75% of the world s production coming from the Sudan. The best grade comes from Jicacia Senegal and about 90% of the Sudan s production is from this source the remainder comes Jicacia sejal... 

Vegetable-tanning materials in commercial quantities come from many different countries. Quebracho is a principal tanning material from South America. Wattie or Mimosa is suppHed from several African sources. India and other Asian countries supply a variety of materials including Myrabolans, Gall Nuts, and Tara Pods (3). 

Eluorescent lamps for showing plants use a blue-white phosphor blended with a deep red-emitting phosphor. This more closely corresponds to the action spectmm for plant growth because there is Htfle green in the spectmm, African violets, for example, have leaves which appear more purple in color. The deep red emitter which is commonly used is magnesium fluorogermanate activated by Mn. ... 

Phosphorite Deposits. Sedimentary phosphorites contain low concentrations of uranium in fine-grained apatite. Uranium of this type is considered an unconventional resource. Significant examples of these uranium ore types include the U.S. deposits in Elorida, where uranium is recovered as a by-product, and the large deposits in North African and Middle Eastern countries (16). 

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