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The Benue trough of west Africa is commonly believed to be a rift feature that originated in the Cretaceous at about the time that Africa and South America began to separate. Bouguer gravity and available geological data in the trough indicate that its formation was probably the result of regional horizontal stresses in the lithosphere, causing crustal extension and surface subsidence. By contrast, the data for the adjoining Cameroon volcanic line suggests that the associated tensional...
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The formation of kaolinite-smectite mixed-layered clays results from weathering of smectite in leached and silica-depleted environments. Halloysite-smectite mixed-layered clays have been proposed to form from weatherable minerals in volcanic ash soils through simultaneous formation of 1:1 and 2:1 units in silica-rich environments. Here, we report a mineralogical study of weathered B horizon material from soils developed on Late Quaternary fluvio-volcanic deposits of basaltic origin at the...
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Abstract The aim of this study was to examine racial discrimination of South African students using playing strategy in the prisoners dilemma game as an unobtrusive measure. University students (30 white and 30 black men) each played two 30-trial games, one with a black confederate and one with a white confederate. In each game, the students played against an identical 60% noncontingent strategy. Both the black and white students cooperated to a significantly greater extent with the black...
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It appears that drought has no influence on beef prices. However, beef prices are sensitive to a cattle cycle of approximately seven years. This suggests that the Meat Board price stabilisation controls prevent prices falling in times of drought but permit cyclical variations of plus or minus twenty percent. These results are contrary to the impressions of most people. It is important for beef farmers to recognise the influence of the cattle cycle on their profit margins. By pre-empting the...
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Drought is a recurrent phenomenon. In Ethiopia droughts have occurred quasi-periodically during the last several centuries. Drought is characterized by many facets. The causes of drought are either natural or manmade or both. Scientific investigations have revealed that the primary cause is the fluctuation of the general atmospheric circulation. As a consequence of such fluctuations the rain-producing components for Ethiopia have been weakened or dislocated during drought years. Human...
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This paper discusses some problems of engineering manpower formation in Zimbabwe and outlines the steps that have been taken to resolve these problems. One of the steps, the Engineering Microcomputer-Assisted Learning Project at the University of Zimbabwe, is described here. A control systems course is used to illustrate the courseware development activities and the course re-organisation involved in the CAL strategy of the project. The problem of CAL project evaluation is also highlighted.
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Chinamhora, Zimbabwe is an area of known endemic goiter and iodine deficiency. Out of 211 primary school children living in the area who had been recruited for a study of the effects of iodine administration, 121 were randomly selected for audiometric testing. All had normal hearing. One further child already noted to have hearing difficulties was tested and found to have fairly severe bilateral nerve deafness, although this was unlikely to have been due to endemic cretinism. Urine...
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Abstract 1. 1.|Guinea-pigs were housed at +4°C for four weeks; two groups were studied, one sedentary and a trained group undergoing running for one hour a day 7 days/week. 2. 2.| V O 2 was measured after two and four weeks' adaptation at + 4°C before and after the administration of noradrenalin (NA). After four weeks the oxidative capacity of interscapular adipose tissue (IAT) was determined. 3. 3.|NA increased V O 2 in the trained animals more than in the controls after two and four weeks'...
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A community based cross-sectional study on the prevalence and causes of blindness and visual impairment was carried out between August and December 1985 in the Luapula Valley. The study population consisted of 2503 villagers aged 6 years and above. Visual acuity was done on every participant whereas slit-lamp examination and ophthalmoscopy were done on selected individuals when indicated. The overall prevalence of monocular and bilateral blindness was 6.9% and 3.6% respectively. Cataracts...