University of Zimbabwe

About: University of Zimbabwe is a education organization based out in Harare, Harare, Zimbabwe. It is known for research contribution in the topics: Population & Acquired immunodeficiency syndrome (AIDS). The organization has 4378 authors who have published 6800 publications receiving 160720 citations. The organization is also known as: UZ & University College of Rhodesia and Nyasaland.

Mechanisms of isostatic compensation in the vicinity of the East African Rift, Kenya

Abstract: Summary The topography and gravity anomalies in the area surrounding the East African Rift in Kenya can be modelled as the sum of the effects of surface and subsurface loading of an elastic plate. Assuming surface and subsurface loading are independent processes, the observed coherence between the 2-D Fourier transforms of Bouguer gravity and topography provides a constraint on the effective elastic thickness or flexural rigidity of the plate. Distinct linear segments of the log gravity power spectrum suggest that components of the gravity field with wavelengths of 250–1000 km are generated predominantly by a density contrast at a depth of about 32 km. Most shorter wavelength gravity anomalies are probably associated with source depths of less than 1 km and indicate variations in thickness of low density sedimentary or volcanic layers or lateral variations in density of the surface rocks. A simple density model based on these estimates and the geology of Kenya consists of a cover layer averaging 0.5 km thick with density 2300 kg m−3, a layer 32 km thick with density 2800 kg m−3, and an underlying half-space with density 3200 kg m−3. Using this density model and assuming loading due to relief on all three density interfaces, the elastic thickness that best predicts the observed coherence in the least squares sense is 25 km (Flexural rigidity of 1.4 × 1023Nm). Amplitudes of loads on the density interfaces can be calculated based on the model response. Topography with wavelength greater than 650 km is locally compensated making surface and subsurface loading indistinguishable. At shorter wavelengths, rift volcanics and volcanic cones including Mts Kenya, Elgon and Kilimanjaro can be identified as surface loads. The largest amplitude subsurface load is an upward directed, regionally supported load beneath the Kenya Dome that may correspond to a region of hot, low density mantle recognized by other geophysical studies. In creating the topography for which surface and sub-surface loading are distinguishable, surface loading is much more important than doming due to subsurface loading.

Assessing the relationship between water quality parameters and changes in landuse patterns in the Upper Manyame River, Zimbabwe

Abstract: For the past 30 years, the increases in population pressure and external influences, such as economic growth, have accelerated the demand for land within the Upper Manyame River catchment in Zimbabwe which has caused substantial changes in landuse. The general objective of this research was to assess the impacts of landuse activities on the water quality of the Upper Manyame River which drains the rural and urbanised part of the catchment up to flow gauging station C21. Landcover data for the month of April in years of 1984, 1995, 2003 and 2011 were acquired from available Landsat TM and ETM images and were classified through the maximum likelihood digital image classification using the supervised classification approach. The status of water quality of the Upper Manyame River was also assessed through analyses of historical concentrations and pollution loads for TP, DO, COD, NH 3 -N, SS, Pb, NO 3 , BOD 5 , EC, PO 4 -P and TN at the Environmental Management Agency (EMA) gauging station CR21 sampling point for 1996, 2000/1 and 2008/9. Water quality of 15 monitoring sites comprising 25 water quality parameters were monitored monthly from January to June 2012. These locations were selected to reflect a wide array of landuse for both the dry and wet seasons. The results indicated that there was an increase in pollution load from 1995 to 2012; for TP from 130 kg/day to 376 kg/d, and for TN from 290 kg/day to 494 kg/d. This indicates high pollution levels which have severe impacts on downstream users and also severe sewage contamination. Significant deviations occurred in DO (0.1–6.8) mg/L, COD (11–569) mg/L, BOD 5 (5–341) mg/L, PO 4 -P (0.01–4.45) mg/L, NH 3 -N (0.001–6.800) mg/L and EC (38–642) μS/cm. Hydrologic Response Unit and buffer analysis were used to determine the dominant landuse which contributes to a certain water quality. Results of digital image classification indicate that woodland/forest, grassland and bareland decreased between years 1984 to 2011 by 24.0%, 22.6% and 31.7% respectively. This was mainly due to expansion or increase of agriculture and urban areas by 24.4% and 41.6% respectively over the same time period. It was concluded that settlements and agricultural areas are the ones mainly affecting the water quality in Upper Manyame River with a Pearson’s Correlation Coefficient of r = 0.97 for COD and r = 0.78 for TSS respectively. It was also observed that the water quality status of the Upper Manyame River and its tributaries is very poor and the level of pollution generally increases from upstream to downstream. The results obtained provided baseline information which may be used in the development of appropriate water quality management systems in the catchment. Thus the study recommended a combined programme of point source control and landuse modification.

An automated dynamic chamber system for surface exchange measurement of non-reactive and reactive trace gases of grassland ecosystems

Abstract: . We present an automated dynamic chamber system which is optimised for continuous unattended flux measurements of multiple non-reactive and reactive trace gases on grassland ecosystems. Main design features of our system are (a) highly transparent chamber walls consisting of chemically inert material, (b) individual purging flow units for each chamber, and (c) a movable lid for automated opening and closing of the chamber. The purging flow rate was chosen high enough to keep the mean residence time of the chamber air below one minute. This guarantees a proven efficient mixing of the chamber volume and a fast equilibration after lid closing. The dynamic chamber system is able to measure emission as well as deposition fluxes of trace gases. For the latter case, the modification of the turbulent transport by the chamber (compared to undisturbed ambient conditions) is quantitatively described by a bulk resistance concept. Beside a detailed description of the design and functioning of the system, results of field applications at two grassland sites are presented. In the first experiment, fluxes of five trace gases (CO2, H2O, NO, NO2, O3) were measured simultaneously on small grassland plots. It showed that the dynamic chamber system is able to detect the characteristic diurnal cycles with a sufficient temporal resolution. The results also demonstrated the importance of considering the chemical source/sink in the chamber due to gas phase reactions for the reactive compounds of the NO-NO2-O3 triad. In a second field experiment, chamber flux measurements of CO2 and methanol were compared to simultaneous independent eddy covariance flux measurements on the field scale. The fluxes obtained with the two methods showed a very good agreement indicating a minimal disturbance of the chambers on the physiological activity of the enclosed vegetation.

Early Missionaries and the Ethnolinguistic Factor During the ‘Invention of Tribalism’ in Zimbabwe

Abstract: There is evidence from across the disciplines that at least some of the contemporary regional names of African tribes, dialects and languages are fairly recent inventions in historical terms. This article offers some evidence from Zimbabwe to show that missionary linguistic politics were an important factor in this process. The South African linguist Clement Doke was brought in to resolve conflicts about the orthography of Shona. His Report on the Unification of the Shona Dialects (1931) shows how the language politics of the Christian denominations, which were also the factions within the umbrella organization the Southern Rhodesia Missionary Conference, contributed quite significantly to the creation and promotion of Zezuru, Karanga and Manyika as the main groupings of dialects in the central area which Doke later accommodated in a unified orthography of a unified language that was given the name Shona. While vocabulary from Ndau was to be incorporated, words from the Korekore group in the north were to be discouraged, and Kalanga in the West was allowed to be subsumed under Ndebele.Writing about sixty years later, Ranger focusses more closely on the Manyika and takes his discussion to the 1940s, but he also mentions that the Rhodesian Front government of the 1960s and 1970s deliberately incited tribalism between the Shona and the Ndebele, while at the same time magnifying the differences between the regional divisions of the Shona, which were, in turn, played against one another as constituent clans. It would appear then that, for the indigenous Africans, the price of Christianity, Western education and a new perception of language unity was the creation of regional ethnic identities that were at least potentially antagonistic and open to political manipulation.Through many decades of rather unnecessary intellectual justification, and as a result of the collective colonial experience through the churches, the schools and the workplaces, these imposed identities, and the myths and sentiments that are associated with them, have become fixed in the collective mind of Africa, and the modern nation states of the continent now seem to be stuck with them. Missionaries played a very significant role in creating this scenario because they were mainly responsible for fixing the ethnolinguistic maps of the African colonies during the early phase of European occupation. To a significant degree, these maps have remained intact and have continued to influence African research scholarship.

HIV Infection Presenting in Older Children and Adolescents: A Case Series from Harare, Zimbabwe

Abstract: Background. Symptomatic human immunodeficiency virus (HIV) infection during late childhood and adolescence may be an emerging problem in southern Africa, but it is one that is poorly described. We investigated social and clinical features in patients of this age group presenting to a HIV treatment clinic with special adolescent services in Harare, Zimbabwe.Methods. All patients aged 8-19 years and their guardians who attended an adolescent HIV treatment clinic were asked to consent to an interview and a review of medical notes.Results. Of 32 patients, 17 (53%) were male. The median CD4 cell count at presentation was 101 cells/mu L (interquartile range, 35-197 cells/mu L). Sixty-two percent experienced stunting (mean Z score for height-for-age, -2.55; 95% CI, -2.00 to -3.10), and all presented with World Health Organization stage 3 or 4 HIV infection. The median age at the first HIV test was 11 years, with a median of 3.5 years delay since the first HIV-related illness. Recurrent respiratory tract infections, skin complaints, diarrhea, and past tuberculosis were the most common HIV-related complaints. Seventeen patients (55%) were double orphans, and 10 (62%) surviving parents were known to be HIV positive.Conclusions. In this small study, HIV-infected adolescents were profoundly immunosuppressed, with characteristics suggesting long-standing HIV infection. The equal sex distribution and high incidence of parental and sibling mortality were consistent; the majority of children had HIV-infected parents and, therefore, were potentially long-term survivors of HIV infection due to mother-to-child transmission. Greater recognition of the substantial burden of undiagnosed HIV infection and acquired immunodeficiency syndrome in this age group is needed, together with services aimed at reducing barriers to earlier diagnosis and initiation of treatment.