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Effect of initial antiretroviral regime on virological suppression in children in a Southern African urban population: a retrospective record reviewGaibee, Zeenaat 22 April 2020 (has links)
Background Since 2010, adult studies and clinical concerns about stavudine (d4T) toxicity had led to the phasing out of d4T from many antiretroviral treatment (ART) guidelines globally with substitution by abacavir. Recent studies, within Southern Africa, however have shown poorer virological suppression with abacavir (ABC) compared to d4T at their respective centres. Methods A retrospective study of HIV-positive children, who had been initiated on ART from 2005 to 2017, was conducted at an ART unit at New Somerset hospital, Western Cape, South Africa. Data was extracted from clinical notes and electronic medical records and virological suppression reviewed in those started on ABC and d4T based regimes. Results A total of 672 children were included in the study with a median age of 8.9 months (interquartile range (IQR) 4.1- 24.1 months) in the d4T based group and 11 months (IQR 3.5 - 29.9 months) in the ABC group. 64 of the 437 patients in the d4T containing group were transferred out, 15 reported to have died, and 49 were lost to follow up within the first 6months on treatment. Of the 181 ABC containing regimen group, 1 was transferred out to another care facility, 1 reported death within 6months of treatment and 2 children were lost to follow up. There was a noted increased risk of being virologically unsuppressed at 6months while taking ABC containing regimen compared to a d4T containing regimen. . The relative risk of being virologically unsuppressed at 6 months while taking abacavir/lopinavir (LPV/r) was 1.39 (95% confidence interval 1.03 to 1.88, p=0.04) compared to stavudine/LPV/r. The relative risk of being virologically unsuppressed at 6 months while taking abacavir/efavirenz (EFV) was 1.82 (95% confidence interval 0.98 to 3.37, p=0.054) compared to stavudine/EFV. Conclusion Our analysis again raises concerns about virological suppression in the abacavir era of paediatric ART, compared to the previous stavudine era, particularly in combination with LPV/r in the younger, more vulnerable children. Whether this is because of intrinsic properties of the different medications or is a marker of the evolving complexity of the South African ART rollout, may never be resolved. However, this is of concern as abacavir and LPV/r appear to be entrenched as first-line paediatric ART in a setting where attrition is high, many children are lost to follow up and virologic surveillance is not always optimal. Clinicians need to optimize retention strategies, especially of young infants, to ensure that children are retained in care, have viral load testing timeously, so that those virologically unsuppressed can be detected and treated early and appropriately.
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Conservation biology of the giant bullfrog, Pyxicephalus adspersus (Tschudi, 1838)Yetman, Caroline Angela 03 September 2012 (has links)
The giant bullfrog, Pyxicephalus adspersus, is a large, explosive-breeding anuran from
southern Africa, which spends most of the year buried in a state of torpor. In South Africa
this species is considered to be Near-Threatened by habitat loss and other factors,
especially in the densely human populated Gauteng Province. The aim of this thesis was
to obtain essential outstanding information about the ecology of P. adspersus to
contribute towards improved conservation management of this species.
A model was used to predict the geographic range of P. adspersus in southern Africa, and
recent land cover data were used to determine the amount of suitable habitat remaining
for this species in Gauteng. As a step towards identifying P. adspersus conservation
management units, genetic structure and gene flow for populations from 23 localities in
Gauteng and seven additional localities in the north-eastern interior of South Africa was quantified using 708 base pairs of the mitochondrial gene cytochrome b. To investigate
the unpredictable activity and unknown spatial habitat requirements of P. adspersus, a
population’s spawning and non-breeding activity was monitored, and the movements of
70 adult frogs were radio- or spool-tracked during five summers at a site in Diepsloot,
Gauteng. Using skeletohronology, the age distribution of breeding P. adspersus at this
and two other peri-urban sites near Johannesburg, Gauteng, was examined.
Bioclimatic conditions were predicted to be suitable for P. adspersus in the temperate to
semi-arid interior, but not the low-lying eastern subtropical and arid western sides of
southern Africa. Limited genetic data suggested that P. adspersus was common in the
north-eastern interior of South Africa, and that populations in the Free State Province
represent an evolutionary significant unit of this species. In central Gauteng, where P.
adspersus may have declined by > 90%, populations < 20 km apart exhibited significant
genetic differentiation, possibly as a result of genetic drift. At Diepsloot, both annual
numbers of spawning events and numbers of spawning males were positively correlated
with rainfall, although other meteorological variables also affected the activity of P.
adspersus. Radio- or spool-tracked frogs showed high fidelity to their breeding site and
burrows, which were situated up to 1 km away from the water. Male P. adspersus
probably live 20 years in the wild, but at some peri-urban breeding sites adult life
expectancy and body size may be declining.
The geographic range of P. adspersus was predicted to be slightly smaller than that
reported by other authors, and deserves phylogeographic validation. The main conservation priority for P. adspersus in South Africa should be the protection of
terrestrial habitat for adult foraging and aestivation around, and for juvenile dispersal and
gene flow between, breeding sites. In Gauteng, the conservation of a P. adspersus metapopulation
is critical, and could most likely be achieved in the northern region of this
province. Populations in the Free State Province deserve improved protection given their
reported genetic uniqueness. At local spatial scales specific threats (e.g. pollution) should
be ameliorated, and long-term monitoring should be implemented to detect real
population trends. / Thesis (PhD)--University of Pretoria, 2012. / Zoology and Entomology / Unrestricted
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Systematics of subtribes Athanasiinae and Phymasperminae (Anthemideae, Asteraceae)Akimana, Solange January 2020 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / The tribe Anthemideae is a large tribe of the family Asteraceae comprising 111 genera and 1 800 species distributed in Africa, Europe, Asia, and the Northern temperate region, with southern Africa as one of its main centers of diversity, together with Central Asia and the Mediterranean. Ongoing studies have focused on analysing relationships among the southern African subtribes of Anthemideae and the most recent classification recognised fourteen subtribes in which there is a clear biogeographical gradient, with the six southern African subtribes comprising the earliest diverging lineages. The present study focuses on two of these southern African-centred lineages (viz. subtribes Athanasiinae and Phymasperminae). Previous phylogenetic studies of the tribe were based on nuclear nrDNA ITS and plastid cpDNA ndhF sequence data and included only a single representative from each of the genera within the subtribes Athanasiinae and Phymasperminae. / 2024
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Geochemistry of the Sabie River Basalt Formation in the central Lebombo, Karoo Igneous Province / Geochemistry of the Sabie River Basalt Formation in the central Lebombo, Karoo Igneous ProvinceSweeney, Russell James, Sweeney, Russell James 23 November 2016 (has links)
The Sabie River Basalt Formation is a group of tholeiitic basaltic rocks erupted ca 190 Ma ago in the eastern zone of the Karoo Igneous Province of southern Africa. It is traceable over a distance of 700 km from Zululand, northwards along the Lebombo monocline into the Transvaal and south-east Zimbabwe. An abrupt compositional change in this formation occurs about halfway down its length in the vicinity of the Sabie and Komati Rivers: basalts to the north are known to be enriched in certain incompatible elements relative to basalts in the south, which are comparable in geochemistry to most basaltic rocks in the southern part of the Karoo Igneous Province. New data obtained in this work include 134 major and trace element whole-rock analyses, some 400 analyses of constituent minerals, 38 ⁸⁷Sr/⁸⁶Sr ratio determinations, 19 ¹⁴³Nd/¹⁴⁴Nd ratio determinations, 16 common Pb determinations and 12 oxygen isotope analyses. The "normal" (N) and "enriched" basaltic rocks are distinguished by differences in the concentrations of Ti, P, Zr, Nb, Y, La, Ce and Nd (high field strength elements). Broadly these differences are substantiated by K, Rb, Ba and Sr, but with much more overlap. The "enriched" group of basaltic rocks has been further subdivided into a low-Fe "enriched" (LFE) group and a high-Fe "enriched" group (HFE). The LFE-group basalts, which predominate at the base of the stratigraphic sections, are considered to be equivalent to basalts occurring in the N. Lebombo. In the central Lebombo N-group basalts predominate in the mid- and upper portions of the sections and HFE-group basalt occurs near the top of each section. Interbedding of all basalt groups occurs in the Sabie River section at the northern end of the study area, while the N- and HFE-group basalts are interbedded in the Crocodile and Komati River sections further to the south. The decrease in LFE-group basalt abundance southwards is accompanied by an increase in N-group basalt abundance. HFE-group basalts appear to be unique to the central Lebombo area of the Karoo Igneous Province and are volumetrically less significant than N- or LFE-group basalts. Petrogenetic models involving closed-system fractional crystallization; coupled assimilation (of granitic crust) fractional crystallization; replenished, tapped and fractionated magma chambers and partial melting are examined. Granitic crustal contamination appears to have been significant only in some samples of the N group where assimilation of granitic material has proceeded in a bulk fashion described by an AFC model. RTF models are dynamically more realistic than closed-system fractional crystallization models and explain increases in incompatible elements with decreasing MgO in the LFE and HFE groups. Variations in the N group, however, require varying degrees of partial melting of a N-type source to be explained fully. RTF models may explain the absence of any stratigraphic correlations of element abundances in the three groups. The HFE group may be related to an uncontaminated N-type parent composition by a combination of continued fractional crystallization from an N-group parent composition and varying degrees of partial melting of an N-type source. The only petrogenetic process by which the N and LFE groups may be related is different degrees of partial melting. However, this demands a source composition which has no resemblance on trace element and isotopic grounds, to observed mantle xenolith compositions. The preferred model is one in which the LFE group is derived from old sub-cratonic mantle similar to garnet-bearing "cold" peridotite xenoliths and the N group from a source similar in composition to estimates of primitive mantle. The existence of two types of mantle derived continental flood basalt magmas occurs in other Mesozoic basalt provinces in "southern" Gondwanaland (e.g. Kirwanveggan of Antarctica, Etendeka of Namibia and the Parana Basin of South America). It is suggested that there is a geographical association of LFE-type basalts with Archaean crust (or Archaean crust re-worked in low temperature - high pressure events) and N-type basalts with post-Archaean crust (or Archaean crust re-worked in high temperature - low pressure events). This model suggests the derivation of the LFE group, from old sub-cratonic lithospheric mantle relatively enriched in incompatible elements and the N group being derived from more recently accreted and less enriched lithospheric mantle underlying younger crustal terraines.
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Leviticus 18:22 and 20:13 in discussion with the Methodist Church of Southern Africa on homosexualityMtshiselwa, Vincent Ndikhokele Ndzondelelo 15 October 2010 (has links)
In recent times, the texts of Leviticus 18:22 and 20:13, has attracted the attention of Old Testament scholars, clergy and the laity alike. In my view, such an attention has been inspired by the readers’ quest to the possible light which the text can shed on the subject of homosexuality. The latter topic is one of the burning issues raised in present day South Africa. It thus comes as no surprise, that interpreting texts such as Leviticus18:22 and 20:13 becomes pertinent in our context. This research aims at coming up with a constructive dialogue between the Methodist Church of Southern Africa (hereafter referred to as MCSA)’s readings of this text, scholars’ interpretation of the same and the Xhosas’ reception of homosexuality in the Republic of South Africa. Through the use of methodologies such as the Literary, Textual, Canon, Composition and Redaction Criticism, as well as Socio-Scientific Criticism, Leviticus 18:22 and 20:13, will be brought to bear with its MCSA’s readings and Xhosas’ readings with a view to making a necessary contribution to African biblical hermeneutics. / Dissertation (MA(Theol))--University of Pretoria, 2010. / Old Testament Studies / unrestricted
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Internal variability of the regional climate model RegCM3 over Southern AfricaKgatuke, Mary-Jane Morongwa 13 August 2007 (has links)
Global Climate Models (GCMs) and Regional Climate Models (RCMs) represent the atmospheric processes that are nonlinear by nature and are therefore sensitive to small perturbations. The RCMs are provided time dependent Lateral Boundary Conditions (LBCs) either from the GCM or the reanalyses and hence the RCMs are not expected to deviate much from the forcing fields as expected for a free non-linear system. If a GCM is used in a nested system, the nested solutions will be subject to the internal variability of both the GCM and the RCM. The study aims to investigate the variability caused by the internal variability of the GCM and the RCM. The study then looks into the contribution of the RCM’s internal variability to the total variability of the different nested system solutions. In this study four solutions obtained through perturbing the wind fields at initialisation for the ECHAM4.5 are used to force an RCM, the RegCM3, over South Africa. The solutions that are obtained are functions of the internal variability of the ECHAM4.5 as well as of the RegCM3. To determine the amount of the variability that is introduced by the RCM’s internal variability, four other RegCM3 simulations are made through initialising the RegCM3 on different days but using a single realisation from the GCM. The rainfall variability associated with the combined internal variability of both the models is high to an extent that ensemble members produce anomalies that have opposite signs in the same season. However, the sign of the ensemble average anomaly generally corresponds with the observed anomaly. The variability associated with the internal variability of the RCM is negligible when seasonal totals are analysed while with the daily rainfall totals the variability is larger. The variability in areas where small amounts of rainfall occur is smaller than that of the high rainfall regions. The number of events that fall into the three rainfall categories (i.e. below-normal, normal and above-normal) for the RegCM3 ensemble members are close to one another however the timing of the events is different. The results suggest that in operational forecasting making ensemble members associated with the internal variability of an RCM is not necessary because the information obtained from the ensemble members is almost similar. / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / MSc / Unrestricted
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Decentralisation and Recentralisation in Anglophone Southern Africa: Factors driving the EBB and flow of powerMadhekeni, Alois January 2020 (has links)
Philosophiae Doctor - PhD / Literature on multilevel government is replete with the virtues of decentralisation as a governing model. As a result, the discourse of decentralisation has found its way into the constitutions, legislation and policy documents of most African states, including those that are ostensibly centralised. However, the enthusiasm for the juridical form of decentralisation is not reflected when it comes to the actual distribution of state power. In practice, the distribution of power ebbs and flows as states hover between decentralisation and centralisation. In other words, regardless of juridical commitments, states hardly ever promote decentralisation consistently, but move between cycles of decentralisation and recentralisation. Thus, once reforms that promote decentralisation have been adopted, they are shortly followed by a wave of recentralisation, which lasts until it in turn, is replaced by a further push for decentralisation. Consequently, the cycles are repeated. The central quest of this study is to explain the factors driving this cyclical pattern. It raises the following questions: Why are states seldom consistent with respect to decentralisation? What drives decentralisation? What drives recentralisation? What does this mean for the future of decentralisation? A comparative study of five Anglophone countries in Southern Africa was conducted with a view to analyse the waves of decentralisation and recentralisation both within and across countries over long periods of time. The countries were chosen in terms of their similar historical background and regional concentration. They are the countries of Botswana, Malawi, Namibia, South Africa and Zimbabwe. The study traced the process of decentralisation in these countries from the precolonial and colonial period up until 2019, examining historical, legal, constitutional, economic and political documentation and scholarship. In some cases, in-depth interviews with key informants were conducted to supplement evidence collected through desk-top research. The central argument of this study is that ruling elites are rational actors who make calculated moves based on external and internal pressures, threats to their power, and opportunities to increase it. Evidence from the five countries under study indicate that governments always prefer to centralise power and would maintain the status quo until a political or economic crisis arises. Such crises tend to open up spaces in which other actors are able to negotiate for decentralisation. These other actors include opposition political parties, minority ethnic groups and donors. However, because decentralisation is driven by crisis resolution negotiations, it faces challenges at the implementation stage, and this is always accompanied by a fresh wave of recentralisation. In the wake of this vicious cycle, it is concluded that decentralisation can be sustained if measures are put in place to contain the reverse wave of recentralisation and its unravelling effects. The measures include constitutional protection, the strengthening of the rule of law, good governance at local levels, and support from political parties.
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Conceptualisations and applications of eco-hydrological indicators under conditions of climate change.Barichievy, Kelvin Charles. January 2009 (has links)
Anthropogenically-induced climate change has the potential to have serious implications on aquatic ecosystems and may ultimately affect the supply and quality of freshwater lakes and rivers throughout the world. As a class of ecosystems, inland waters are vulnerable to climatic change and other pressures, due to their small size and their position in the landscape. There is therefore a need to assess the impact of projected climatic change on aquatic ecosystems. Owing to this need, ecological indicators have been developed as a method of quantifying, identifying, monitoring and managing the ecological integrity of aquatic environments. The aim of this research was to develop techniques in order to conceptualise the higher order impacts of projected climate change on environmentally related streamflows and water temperature in South Africa, and to simulate these using an appropriate hydrological model. For this dissertation the downscaled daily climate output from the ECHAM5/MPI-OM General Circulation Model (GCM) was used as an input into the daily time step conceptualphysical ACRU Agrohydrological Modelling System in order to simulate the impacts of projected climate change on selected eco-hydrological indicators at the Quinary Catchment spatial scale. In this research these indicators were grouped into two broad categories: 1. Ecological Flow Indicators and 2. Water Temperature Indicators. The results of this research took the form of maps and time series graphs. The ecological flow indicator results investigate the magnitude and duration of flow events and were analysed spatially for the 5 838 hydrologically interlinked and cascading Quinary Catchments constituting the southern Africa study region. The ECHAM5/MPI-OM GCM projects the magnitude and duration of both annual subcatchment runoff and accumulated streamflows to increase in the eastern parts of southern Africa for the intermediate future climate scenario (2046 - 2065), with this trend strengthening in the distant future climate scenario (2081 - 2100). The computationally intensive water temperature indicator results were analysed spatially at the scale of the Thukela Catchment. The Thukela catchment was selected as a case study area because of its diversity - in altitude, rainfall, soils and ecological regions, as well as in its population geography and levels of education and employment. This diversity presents a challenge to studies of impacts of projected climate change, including its potential impacts on water temperatures. The spatial analyses indicate that subcatchment runoff, accumulated streamflows and mixed maximum water temperature are all likely to increase under projected future climate conditions. A temporal investigation, in the form of time series analyses, focused on four water temperature indicators and was performed for 15 selected Quinary Catchments, located within the Thukela Catchment. These temporal analyses indicate that the absolute variability (i.e. standard deviation) of both individual subcatchment runoff and accumulated catchment streamflows, are projected to increase in the future, while the relative variability (i.e. coefficient of variation) is likely to remain much the same or even decrease slightly over time period. These temporal analyses also indicate that there is a noticeable difference in the mixed maximum water temperature within a single Quaternary Catchment due to hydrological flow routing, with an increase in water temperatures as the water cascades downstream from the upper Quinaries to the Quinaries at lower altitudes. The techniques developed and used in this research could aid decision makers involved in ecological and water management planning. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
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Nested climate modelling over Southern Africa with a semi-langrangian limited area modelEngelbrecht, F.A. (Francois Alwyn) 27 March 2006 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / MSc / Unrestricted
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Scenario planning 2020 for Southern African economic empowerment : can Southern Africa leapfrog from an agrarian to a knowledge economySiwale, Mengo 12 1900 (has links)
Thesis (MBA (Business Management))--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: The central question that this research report attempts to answer is how southern African countries can leapfrog from agrarian to knowledge-based economies. There is no single answer to this question, but rather a complex solution. This can best be answered using scenario planning; hence the title 'Scenario planning 2020 for southern African economic empowerment'. Scenario planning is not the only way of answering the central question, but is the one preferred by the author. The scenario-building process helps to identify a number of key forces or factors that impact on the region. Culture and openness were top of the list with regard to importance and uncertainty in answering the central question. Using culture and openness, the author was able to develop a matrix with four quadrants. With these quadrants the author developed four plausible futures for the region, using the other forces identified and listed as characters, guided by the technique developed by experts in the field of scenario planning. The scenario process gives insightful information that helps one appreciate the dynamic forces, both positive and negative, and how they interact with each other to translate into an outcome - be it a desirable or undesirable outcome. There is a strong business case for recognising and appreciating the existence of culture and that this is the reason why people (and their culture) cannot be separated from the way of business. People have a way of life and, in order to do business with them, their culture must be understood. / AFRIKAANSE OPSOMMING: Die sentrale vraag wat hierdie navorsingsverslag probeer beantwoord, is hoe lande in Suider Afrika die sprong van landbou- tot kennis-gebaseerde ekonomiee kan bewerkstellig. Daar is geen enkel-antwoord tot hierdie vraag nie, maar eerder 'n komplekse oplossing. Dit kan die beste beantwoord word deur scenariobeplanning; daarom die titel 'Scenario planning 2020 for Southern African economic empowerment. Scenario-beplanning is nie die enigste wyse om die sentrale vraag te beantwoord nie, maar is die een wat deur die skrywer verkies word. Die scenariobouproses help om 'n aantal sleutelkragte of -faktore te identifiseer wat 'n impak op die streek het. Kultuur en openheid was bo aan die lys met betrekking tot belangrikheid en onsekerheid. Met die gebruik van kultuur en openheid, was dit vir die skrywer moontlik om 'n matriks te ontwikkel met vier kwadrante. Met hierdie kwadrante het die skrywer vier geloofwaardige toekomsbeelde vir die streek ontwikkel, met gebruikmaking van die ander kragte wat geldentifiseer en gelys is as karakters, gelei deur die tegniek deur kenners ontwikkel in die veld van scenariobeplanning. Die scenarioproses hied insig wat 'n mens help om die dinamiese kragte te waardeer, positief sowel as negatief, en hoe hulle met mekaar in wisselwerking is om'n uitslag te bewerkstellig - wenslik of nie-wenslik. Daar is 'n sterk saak uit te maak vir sakeondememings om herkenning en waardering te gee vir die bestaan van kultuur en dat dit die rede is waarom mense (en bulle kultuur) nie geskei kan word van die wyse waarop sakebelange bedryf word nie. Mense het 'n leefwyse en om sake met hulle te bedryf, moet hul kultuur verstaan word.
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