Showing papers by "University of Zimbabwe published in 1983"

The Feeding Behaviour of Grazing African Ungulates

Abstract: The second to second organization of the foraging behaviour of eleven species of African ungulates is described, with particular emphasis on locomotion while foraging and on the time spent feeding. It was predicted that foraging behaviour should change with the species' body size and stomach specialization and, within a species, with the seasonal or spatial changes in the quality and availability of the food supply. A feeding site was defined as the area which a feeding animal could reach without moving either of its forefeet. Feeding subjects thus encountered a new site every time they took a step with either forefoot and foraging behaviour could be described in terms of the organization of a series of behavioural events (steps) and bouts of activity (feeding). Five indices were used to summarize all records obtained. Only one of these, the proportion of time spent feeding, was significantly correlated with the species' body size. The other four indices include: the rate of movement (in steps per second), the mean feeding time per step, the proportion of sites encountered which carried at least some acceptable food, and the mean time spent feeding from those accepted sites. These last four indices were apparently more strongly affected by the species' stomach specialization than by its body size. The five species with the largest sample sizes (reedbuck, impala, tsessebe, wildebeeste, buffalo) were used to investigate the tendency found within all study species for foraging behaviour to vary seasonally. Firstly, both the mean feeding time per step and the mean feeding time per accepted site were found to be positively correlated with indicators of vegetation bulk and maturity, but negatively correlated with an index of fresh green growth, for all five species: it is suggested that this is due to changes in both the amount of food taken from a given site and in the time needed to ingest a given bulk of food. Secondly, the organization of events within foraging sessions (described in terms of the frequency distributions of step intervals, feeding durations, and the lengths of runs of acceptance or rejection of feeding sites) varied through the year: in particular, food patch size, indicated by the length of sequences of accepted sites, was apparently largest just before the end of the rains, when the vegetation should have been most uniform in quality. Thirdly, the reedbuck is a specialist grazer which, because of its body size, might be expected to feed very selectively within the grass layer: the feeding behaviours of the other four species most closely resembled that of the reedbuck when these four species were feeding off long grass in the dry season, conditions which presented them with much low quality food senescent grass hampering access to very small amounts of higher quality green matter. It is suggested that, as in domestic ungulates, feeding behaviour varies within a species with the proportion of low fibre, high protein, green growth in the vegetation, and in the contrast in quality between the various plant parts. A multivariate analysis was used to identify the foraging characteristics of individual ruminant species. Species which were specialist grass feeders (bulk/roughage feeders) encountered more sites more predictably, and spent more time feeding off those sites, than did species which were known to switch from grasses to other food sources to take advantage of changes in the relative quantity and abundance of food types in the habitat (intermediate feeders). It is suggested that, since pure grazers' foraging is limited to a fairly continuously distributed food supply, their foraging consists mainly of teasing out and biting off grass leaves and the organization of their foraging behaviour is determined by the structure and quality of the grass sward. Intermediate feeders, on the other hand, had the option of taking higher quality but less continuously distributed items, such as fruits, and their foraging may have involved seeking out and moving between such items. Pure grazers' foraging behaviour is thus seen as being dominated by food capture and handling events, while intermediate feeders may be more strongly influenced by food search or pursuit requirements. It is likely that grazers differed from intermediate feeders not only in the basic organization of their foraging behaviour, but also in the way that this organization was affected by the species' body size.

Effects of chromium III on fasting blood glucose, cholesterol and cholesterol HDL levels in diabetics.

Abstract: Chromium deficiency; Malnourishment; Glucose tolerance; Diabetes; Developing world; Zimbabwe; Fasting; Cholesterol; HDL; Blood sugar;

Microvascular injury during gastric mucosal damage by anti-inflammatory drugs in pigs and rats.

Abstract: References [1] B.B. VARGAFTIG, M. CHIGNARD, J. BENVENISTE, J. LEFORT and F. WAL, Background and present status of research on platelet activating factor (PAF-acether), Ann. N.Y. Acad. Sci. 370, 119-137 (1981). [2] C.V. WEDMORE and T.J. WILLIAMS, Platelet-aetivating factor (PAF), a secretory product of polymorphonuclear leucocytes, increases vascular permeability in rabbit skin, Br. J. Pharmac. 74, 916-917P (198 I). 13] N.P. STIMLER, C.M. BLOOR, T.E. HUGLI, R.L. WYKLE, C.E. McCALL and J.T. O'FLAHERTY, Anaphylactic actions of platelet-aetivating factor, Am. J. Pathol. 105, 64-69 (1981). 141 J.L. BEETS and W. PAUL, Actions of locally administered adrenoceptor agonists on increased plasma protein extravasation and blood flow in guinea-pig skin, Br. J. Pharmac. 70, 461-467 (1980). 151 C.P. PAGE, W. PAUL and J. MORLEY, An in vivo model for studying platelet aggregation and disaggregation, Thrombos. Haemostas. 47, 210-213 (1982).

Rhipicephalus zambeziensis as a vector of bovine Theileriae.

Abstract: Rhipicephalus zambeziensis was shown experimentally to transmitTheileria parva parva in cattle from nymph to adult andTheileria parva lawrencei, Theileria parva bovis andTheileria taurotragi from larva to nymph and nymph to adult. In a single trial the tick failed to transmitTheileria mutans. The tick is believed to be a vector ofT. parva lawrencei in the field in Zimbabwe.

Wood decomposition in an abandoned beech and oak coppiced woodland in SE England

Abstract: The rate of litter decomposition is often expressed as a constant decay rate (k; g g−1 yr−1) or as the time required for a certain percentage (often 95% and estimated as 3/k) of it to decompose (termed turnover time). Estimates of k may be obtained by determining the weight loss of litter in the field and also by assuming a steady state and obtaining the ratio of litter input: standing crop. Both methods were used to estimate decay rate and turnover times for beech and oak branches and twigs decomposing on the forest floor and these were critically evaluated. Considerable variation, ranging between 1.8–144.5 yr, was found between the 95% turnover time estimates of various size components of the two species, obtained from woodfall and standing crop data. Likewise variation in decay rate of 2–2.5 cm diameter beech branches, estimated from field experiments, was large both between and within groups of branches categorised according to initial state of decay and presence or absence of bark. The mean annual decay rate for the various categories ranged between k = 0.165-0.452 g g−1yr−1. Branches without bark generally decomposed more slowly than those with bark. Beech twig (<0.5 cm diameter) decomposition rates, from field experiments, ranged between k = 0.149-0.220 g g−1yr−1 and variation was relatively low compared with that of branches. No significant differences (P<0.05)were detected between twig decomposition rates obtained from experiments initiated at different seasons although there was a slight decline in decay rate in winter months. Twig and branch decomposition rates fell within the range found in the few other comparable studies.

Cr Mica from the Precambrian Erris Complex, NW Mayo, Ireland

Abstract: Cr micas identified as chrome phengites occur in association with other Cr-rich minerals in a peculiar schist which lies along a complex shear zone within the pre-Caledonian Erris Complex. The schist generally has a chaotic internal structure but locally there is a crude planar mineralogical zoning with a serpentinebearing zone structurally above a Cr mica zone. Chemical analyses indicate that the schist is a tectonic derivative of a mixture of rock with a pronounced metasomatic character.

A survey of the constituents, availability and use of skin lightening creams in Zimbabwe.

Abstract: The use of skin lightening preparations in Zimbabwe was investigated in 1982 A survey of the products available and their contents, revealed that hydroquinone in concentrations of 2% to 6% is used as the active ingredient in them all A questionnaire was distributed amongst users of these preparations in Zimbabwe The creams were found to be used as multipurpose preparations for depigmenting, smoothing and removing blemishes from the skin Adverse effects being suffered following use of the creams include irritation, sensitisation, dermatitis and hyperpigmentation with ochronotic changes These problems are similar to those which have been encountered and documented elsewhere During the period June to October, 1982, a study was carried out to obtain information on: 1 What skin-lightening products are available in Zimbabwe 2 Their active ingredients 3 To what extent and for what purposes they are used, and 4 What unwanted effects, if any, have resulted from their use Two groups of compounds have been used as skin lightening agents in this country:

Multistable laser through a nonlinear mirror

Abstract: In this paper we show that a multistable laser is realizable by the use of a nonlinear medium as one of the resonant cavity mirrors. Using the semiclassical laser theory we derive a gain function with many maxima. The resulting gain equation has many real solutions. We discuss the possible application in switching by use of a suitable external perturbation.

Estimation of body water and fat in cattle using tritiated water space and live weight with particular reference to the influence of breed

Abstract: SUMMARY The body composition of 18 each of Mashona, Afrikaner and Hereford heifers was measured at the beginning and after 16 and 32 weeks of the experiment. The heifers not slaughtered at the beginning of the experiment were fed a complete diet containing 132 g crude protein and 12·0 MJ metabolizable energy/kg dry matter. Before slaughter, the animals were deprived of food and water for 24 h. Each animal was infused with 1 mCi of tritiated water (TOH) in order to measure total body water (TBW) and to estimate body fat. The growth rate of the three breeds of heifers was similar despite differences in age and initial live weight. Both TBW and fat proportions, however, differed significantly (P < 0·01) between slaughter stages for each breed and between breeds at each slaughter stage. At the first, second and final slaughter stages the proportions of TBW were: 68·0, 59·4 and 54·5% for Mashona; 70·;5, 64·3 and 58·3% for Afrikaner and 65·3, 57·6 and 46·2% for Hereford heifers respectively. The corresponding proportions of body fat were: 10·2, 18·4 and 24·2% for Mashona; 6·6, 12·0 and 20·0% for Afrikaner and 13·7, 20·8 and 25·8% for Hereford heifers respectively. There was a close relation between empty body weight and live weight at slaughter which was not influenced by breed. Both TBW and fat were estimated more accurately when TOH space and live weight were used jointly. However, the slopes of the prediction equations for each breed were significantly different (P < 0·05) in the case of both total body water and fat. It was necessary to use separate equations for each breed in order to predict either body water or fat. The significance of these findings for the estimation of body fat in live cattle is discussed.

Does Shona have diphthongs

Abstract: ‘Investigation has shown’, writes Doke (1931: 31–2) ‘that at least two diphthongs and occur in certain Shona dialects.’ He does not report the nature of the investigation conducted. The present study suggests that there are no restrictions on vowel combinability, but that there are no grounds for postulating diphthongal unit phonemes in the language.

Scrotal anthrax in a child: a case report.

Abstract: SUMMARYA case of scrotal anthrax is presented. The lesion was found on the skin over the lower pole of the right scrotum in a six-year-old boy. Bacillus anthracis was isolated from the lesion and the child responded well to penicillin.

The death of trees: an essay on the natural economy of the forest*

Abstract: WHEN THE FACULTY of Science was founded in this university, twenty-five years ago, two chairs in the Biological Sciences were established; that of Botany and that of Zoology, a distinction which marks the traditional division of the living world into plant life and animal life. This dichotomy in life science goes back at least to the days of Aristotle but is no longer regarded as defensible by modern biologists who recognize not just two kingdoms of organisms but at least five: the unicellular bacteria andprotista, and the multicellular/?lants, animals and fungi. This change in the categorization of the living world derives in part from an increasing recognition of a fundamental duality in the study of Biology; the thrust on the one hand to account for the readily observable diversity of nature and on the other to explain life in terms of unity in function.

Non-archimedean harmonic analysis on topological semigroups

Abstract: Let K be a complete non-Archimedean valued field, S a commutative topological semigroup (not necessarily locally compact). We study the convolution Banach algebra M(S) of all tight K-valued measures on S and its ideal Ma(S) consisting of all elements μ of M(S) for which the shift map x ↦ x ∗μ is continuous (the analogue of the group algebra). In particular, we show that under reasonable conditions the Fourier-Stieltjes transform is isometric. Furthermore, we describe the images of M(S) and Ma(S) under the Fourier-Stieltjes transform. The results obtained are known for groups but new for topological (semi) lattices.

Categorical characterization of uniform hyperspaces

Abstract: In this paper, we use categorical methods to arrive at a characterization of Hausdorff hyperspaces of separated uniform spaces within a category of ordered uniform spaces. We begin by showing that the hyperspace construction gives rise to a monad H in the category Uni of non-empty separated uniform spaces and uniformly continuous maps. We then identify the category of H -algebras and characterize hyperspaces in this context.

Quality control of pharmaceutical preparations and the Third World.

Abstract: In the developed world the principles of Good Manufacturing Practice and the need for Quality Control of phannaceutical products have been accepted and applied over many years. This article delves into the quality control standards of pharmaceutical preparations in the third world.

Evidence for an inverse relationship between the ventilatory response to exercise and the maximum whole body oxygen consumption value.

Abstract: Ventilatory responses to submaximal exercise loads indicate that in a population of 895 physically active and sedentary male and female subjects, exercise ventilation is inversely related to predicted VO2max. The correlation coefficients for males and females in this relationship are 0.61 (P<0.0001) and 0.26 (P<0.0001) respectively. The slopes of regression lines for V;E/VO2 and VO2max in female and male subjects are −2.59 and −0.91 respectively. This is associated with changes in composition of the expired air in that PCO2 increases and PO2 decreases with greater VO2max. The difference between the mean oxygen and carbon dioxide partial pressures in expired air of individuals in the highest and lowest VO2max ranges are 1.2 kPa (9 mm Hg) and 0.8 kPa (6 mm Hg) respectively.

Topical administration of medications in the lungs

Abstract: SUMMARY A survey has been carried out in Zimbabwe to gain information on pharmacist attitudes and current practice involving patient education in the use of medications for topical administration in the lung. The results of the survey indicated that although there was awareness of patient misuse of the administration devices, most pharmacists did not commonly demonstrate administration techniques to their patients; demonstrations when carried out were predominantly by hospital pharmacists. Few pharmacists were aware of the availability of placebo devices for patient education. Most pharmacists agreed, however, that they would become involved in patient instruction on administration techniques if placebo devices were made available to them. These placebo units, they felt, should be supplied free of charge by the manufacturing companies. Most pharmacists felt that, at present, their patients did not fully understand and were not practising correct administration techniques and therefore required tuition in these matters. The present survey was a pilot study for a larger survey to be carried out in Northern Ireland.

A Dynamic Research Strategy for Universals in the Motivation and Personality Domain

Abstract: The background to this paper is a practical one. Living in Central Africa brings one into intimate contact with the human problems of development — economic, political, social and psychological. As is repeatedly pointed out by national and international agencies, the problems are numerous and enormous and exceed the variety and power of the available solutions, threatening the third world with a more or less rapid slide into a breadline-subsistence state. Political economists, who tend to have an influence on decision-making which is disproportionate to their range of expertise, often initiate developments which fail to reach promised goals. The reason for this appears to be that their plans are “suboptimised,” or to put it another way, their models of human behaviour are oversimplified by assumptions that human action is a simple response to economic resources and opportunities. Consequently, whether the economy in question is dominated by capitalist or socialist ideology, there is often a mismatch between the expectations of the populace in their role as consumers and their capacity as producers to meet these expectations.