4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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Wear Reduction and Media Density Optimization for the Single Stage Pipe Densifier at Sishen Iron Ore’s Beneficiation Plants
(University of the Witwatersrand, Johannesburg, 0202-02) Botha, Simone; Kabezya, Kitungwa
The depleting high-grade iron ore mining supply at Sishen Mine in the Northern Cape, South Africa, has given rise to its beneficiation plants operating at higher media densities to upgrade lower-grade ore. In this study, densification was numerically modelled using an MPPIC model and experimentally tested using a 200-mm diameter centrifugal densifier from two local suppliers – Multotec and HMA. Shear stress, wear rate, separation efficiency and media losses were measured at increasing operating densities and differing vortex finder sizes. Optimum operating conditions were established. It was found that a feed density of 3.60 t/m3 and a shear stress of 9.70 e-3 N/m3 at the inlet using a vortex finder diameter size of 30 mm exhibited favourable performance in terms of media densification and downstream recovery. The practical significance of this is proven in terms of wear rate and its predictability to provide a consistent overflow of below 1.20 t/m3 media to the recovery circuit. Furthermore, information about ideal operating conditions in terms of inlet pressure and controls to identify premature failures were established.
Pegmatite investigations in the Karibib district, South West Africa
(University of the Witwatersrand, Johannesburg, 1963) Roering, Christian
The outer pegmatitie zone of variable thickness which is essentially a very coarse-grained granite consisting of larger perthite phenocrysts lying in a matrix of albite, quartz and muscovite. The inner portions of this zone may reveal a great enrichment of perthite, so much so, that it may grade into a giant perthite zone, e. g. Rubicon main ore-body; Karlsbrunn close to the Li-bearing ore zones. This outer portion of the pegmatite may also reveal a subdivision into two distinct units: an outermost zone of albite-quartz-muscovite and an inner zone of albite-perthite-quartz-muscovite. This sequence of essentially granitic crystallization is often abruptly broken by the appearance of a zone consisting essentially of cleavelandite with minor quartz and muscovite. This zone is characterized by the appearance of numerous accessory minerals often in economic quantities, e. g. beryl, columbite-tantalite-frondellite, topaz and apatite. The zone is generally of the order 1-5 feet depending on the original size of the pegmatitie and the degree of fractionation. That it is not a late replacement unit is confirmed by observations at Rubicon where corroded crystals of beryl belonging to this zone are found lying in a matrix of lepidolite and albite which is the next unit to form. The lepidolite-albite zone in fact replaces the beryl-bearing zone. The striking symmetry alone of the Rubicon body testifies to this zone preceeding in crystallization sequence the Li-ore zones. The significant fact about this zone is that it marks a distinct break in the crystallization history of the pegmatite, i. e. it marks the change from crystallization of essentially granitic components to the formation of late phase constituents, viz. Li-bearing and associated minerals. It possibly marks the break from magmatic crystallization to late-magmatic conditions when pneumatogenic and even hydrothermal processes begin to operate. The next group of minerals to form are noticeably rich in Li and are frequently associated with sugary albite. The major minerals are petalite, lepidolite and albite, while minor amounts of amblygonite also occur. There is a definite spacial relationship sequence in the formation of these minerals. Petalite crystallizes first and collects in the upper part of this unit generally forming a hood. Amblygonite, albite, quartz, may occur at the same time. Immediately below this petalite hood, and at a somewhat later stage, fine-grained lepidolite crystallizes together with albite and minor quartz. The final phase to form at this general stage is sugary albite which collects at the bottom of the still non-crystalline portion of the magma chamber. The sugary albite phase is able to behave diapirically and can intrude, brecciate, and replace any of the previously crystallized zonal constituents. Each successive stage here can assume corrosive relationships to previously consolidated units. No assessment is made as to the amount of replacement that may take place as the criterion commonly used for such diagnosis are somewhat subjective. During this entire process of complex diffusions and crystallization, silica is apparently being concentrated in the residual fractions of the pegmatite magma. The next zone to form is a cleavelandite-rich rock confined to the quartz core margin. This cleavelandite is able to vein and brecciate and corrode the immediately adjacent lying lepidolite and is often associated with minerals such as beryl, columbite, tantalite, tourmaline, topaz and apatitie. Amblygonite may also belong to this stage of mineralization though in general it tends to be associated close in time with the petalite stage of mineralization. The final stage of the crystallization sequence is the quartz core. Quartz veinlets emanating from the core have been observed to cut across adjacent lepidllite-rich and amblygonite-albite zones. Euhedral crystals of columbite and beryl at the core margin are completely surrounded by quartz. These observations may suggest that quartz, although concentrated in the centre of the dyke, probably existed in some unconsolidated state (e. g. a gel as Brotzen (1959) has suggested). The development of a gas phase at certain stages of the pegmatites consolidation history possibly accounts for the vertical fractionation found in these pegmatites. Finally details of the more important pegmatite minerals are given together with chemical analyses.
The Quantitative Hydrogeological Mapping of Zebediela Estates, Central Transvaal
(University of the Witwatersrand, Johannesburg, 1970-05) Pretorius, Desmond Aubrey
The groundwater system on zebediela Estates, situated along the northern edge of the Springbok Flats in the Central Transvaal, has been studied by physiographic, geologic , geophysical, geochemical, and hydrologic methods . Emphasis has been placed on the subsurface mapping of the spatial distribution patterns of a nvn1ber of hydrogeologic parameters, and computer-based polynomial trend surface analysis has been employed to facilitate the interpretation of the maps. The computer has also been used to determine the general statistics of the frequency distributions of the various parameters and to platform sequential multiple linear regression analysis in an attempt to determine the relationships between the variables . Data arrays of observations, computations, and interpretations have been disp layed in 38 tables in the text and 21 appendices to the text . The distr ibution patterns , in one and two dimensions, have been portrayed in 8 text figures and 117 maps, separate from the t ext. The area studied covers approximate ly 23 square mil es, in which 556, 000 orange trees have been planted on 5800 acres . An average annual amount of 2400 million gallons of water is required to maintain t he operation, and 560 million gallons of this quantity are withdrawn, on the average, each year from boreholes tapping the groundwater resources of the Estates . Up to April, 1969, 315 holes had been drilled, and 151 had become producers at one time or another. In 19 years of exploitation between 1950 and 1968, 10, 600 million gallons of groundwater were withdrawn, at an average rate of 13 million gallons per year per production borehole. The study has shown that the groundwater system supplying this substantial quantity of water consists of two main elements - a piedmont alluvial slope, in which stream channels and paleochannels on coalescing alluvial fans are acting as conduits for the transmistion of water from the intake areas; and an underlying bedrock storage reservoir composed of aquifers of the Transvaal and Karroo sequences . The Malmani dolomite aquifers and the Stormberg basalt aquifers are superior to those of the Wolkberg quartzites, shales, and lavas, and the Stormberg Cave sandstones. It has been possible to distinguish two cycles of Karoo basalts, each of which shows differentiation . The upper cycle is far more important as an aquifer than the lower cycle. The piedmont slope is composed of portions of three alluvial fans , the spines of which have a general southeasterly trend towards the junction of the Nkumpi and Olifant rivers in the valley-flat environment well to the south of the Estates . The upland areas above the apices of the fans embrace the mountain ranges which form the northern rim of the Transvaal Basin, and these uplands have suffered right-lateral movements along extensive east-northeast-trending transcurrent faults which must have continued to be active into recent times in order to displace the stream course on the fans. The fan-head section and portion of the midfan section of the Nkumpi fan, in which the Gompies River is situated, occur over the east-central, eastern, and southeastern parts of the property, and, where underlain by the upper basalt aquifers, constitute the most important source of groundwater on Zebediela Estates. The whole of the fan-head and mid-fan sections of the Mamukebe fan are located in the riorthern, west-central, western, and southwestern localities of the area studied. The fan is much smaller than either of the others, and is underlain by Wolkberg rocks, Cave sandstones, and lower basalts. Its overall groundwater potential is consequently lower than that of either of the other two components of the piedmont slope. Only a very restricted portion of the fan-head section of the Mogoto fan occurs in the extreme northwestern corner of the Estates, where it is underlain by the dolomite aquifer, Its groundwater parameters are consequently very favourable, but the true potential of this fan lies beyond the western boundary of the property. The average yield of boreholes in the upper basalt is 3600 gallons per hour; in the lower basalt, 2000 g.p.h.; in the sandstone, 1500 g.p.h.; in the dolomite, 11,200 g.p.h.; and in the quartzites, 1500 g.p.h. The average yield for all boreholes on the Estates is 4100 gallons per hour. All of these figures are appreciably higher than those for equivalent formations elsewhere in South Africa, testifying to the impoi,tance of the piedmont alluvial slope environment in the overall groundwater system at Zebediela. The average annual recharge of the groundwater reservoirs from all sources has been estimated at 700 million gallons. With the average annual withdrawal being of the order of 560 million gallons, the possibility exists that production from the aquifers can be increased by 25 per cent, without fear of serious, permanent deterioration in the performance of the groundwater system. However, excessive exploitation in times of low recharge might lead to the development of quality h.azards with respect to sodiuum, ehloride, and bicarbonate over the upperbasalts. This possibility does not exist for the remaining aquifers, particularly those in the dolomite, from which relatively pure water is drawn. An added problem in the recharge of the upper basalt aquifer is the contamination of t he groundwater in storage by lithium, brought into the Zebediela groundwater- system by the Nkumpi River, which transmits the element from the granite terrain to the north of the mountainous rim of the Springbok Flats. A new model of groundwater exploration has been devised, based on optimum drilling sites being located where coincidence takes place of piedmont stream channel conduits, dolomite or upper basalt aquifers, and transcurrent fault aquicludes, Results obtained from the employment of this model during two years of drilling subsequent to its development in a preliminary form produced an increase of 14 per cent in the average yield of all boreholes drilled.
Experimental heat transfer coefficients for the cooling of oil in horizontal internal forced convective transitional flow
(University of the Witwatersrand, Johannesburg, 1981) Rogers, Douglas Gordon; Van der Merwe, D.F.
Translating terms of affection and abuse from German to English with special reference to animal metaphors
(University of the Witwatersrand, Johannesburg, 1987) Conze, Ingola; Taylor, Oakshott
Mathematical representation and analysis of articular surfaces: application to the functional anatomy and palaeo-anthropology of the ankle joint
(University of the Witwatersrand, Johannesburg, 1990) Webb, Christie Peter; Tobias, Phillip Vallentine
This thesis is a study of quantifiable variation in the geometric shape of the superior articular surface of the talus of higher primates, with special reference to fossil tali of Plio-Pleistocene hominids. (Abbreviation abstract).
The theory and practice of community participation in provision of urban structure
(University of the Witwatersrand, Johannesburg, 1993) Abbott, John; McCutcheon, Robert
The thesis develops a new approach to community participation, for application to infrastructure provision projects in developing countries, based upon social surveys and case studies of negotiations in five South African communities. Existing approaches to community participation are analysed and shown to be unsuitable for infrastructure provision. The thesis compares the characteristics of infrastructure projects with those of other types of development projects and demonstrates how these characteristics can be used to situate a given project within a project environment defined in terms of two variables: the openness of government to community involvement in decision-making, and project complexity. Social surveys carried out in Soweto and KwaThandeka showed the centrality of infrastructure to social change in South Africa. Existing urban management systems were unable to cope with the stresses placed upon them. Four facets of urban management were identified as being under stress: institutional capacity, legitimacy, affordability, and user convenience. These stresses change the nature of infrastructure provision from the supply of end products into a complex process. Central to this process are: an increased number of actors influencing decisions, the enhanced role of technical professionals, and the social implications of different levels of service. The case-study of KwaThandeka included a study of the negotiation process with the provincial administration. This research led to the development of a performance specification for comparing social, economic and technical measures of value. A new conceptual framework for community participation was derived, based upon the different actors involved in the decision-making process and the different needs of each of those actors. Three case studies from Natal identified different implementation strategies for community participation. Communities were found to have three distinct needs: involvement in the political process; involvement in technical decision-making; and representation as consumers of services. An analytical tool was developed to assist project managers in understanding the relationships between actors in a project. The thesis shows how technical project management can be integrated into the participation process. The success of community participation can be evaluated by assessing the degree of consensus achieved between actors, and the intensity of community involvement.
Man-The-Shaman is it the Whole Story? A Feminist Perspective on the San Rock Art of Southern Africa
(University of the Witwatersrand, Johannesburg, 1995-06) Stevenson, Judith S.
Ethnographic accounts show that both shamanic and gender rituals play a critical role in San culture. Although 30% of the women and 50% of the men become shamans, the literature investigating San rock art frequently defines 'Man-the-Shaman' and minimizes the feasibility of female depictions of this important social role. Prior rock art research has tended to separate shamanic and gender processes to the impoverishment of both. This dissertation investigates the symbolic connections between these two social spheres, and argues that they are inseparable. Through this examination of gender and shamanic roles in San society this dissertation argues that metaphors reflect these two social spheres. It also argues that metaphors are a way of life which are expressed both in reality and non-reality. With these points in mind, it investigates the role of men and women as related to San rock art through social roles.
The role of increased gastrointestinal alcohol production in patients with the metabolic syndrome: Implications for the pathogenesis of non-alcoholic fatty liver disease
(University of the Witwatersrand, Johannesburg, 2006) Menezes, Colin Nigel; Immelman, Ronnie; Raal, Derick
Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease with hepatic histology that resembles alcoholic liver disease. It is a frequent cause of chronic liver disease and is attracting increasing scientific attention worldwide. I explored the possibility that increased gastrointestinal alcohol production may have a role as a “second hit” in the pathogenesis of NAFLD in study subjects with the metabolic syndrome. In an attempt to investigate this hypothesis, this study looked at blood, urine and breath levels of alcohol in patients with the metabolic syndrome versus matched age and ethnic group healthy controls. Of the twenty study subjects, 80% had dyslipidaemia, 60% had hypertension and 70% had type 2 diabetes mellitus. Their mean BMI was 35.1±8.2 kg/m² (mean ± SD, P < 0.0001 versus controls). The serum aminotransferases were significantly elevated in the study subjects, their ALT levels being 57.4±44.79 U/L versus 17.4±4.60 U/L in the controls (95% CI 18.02 – 61.42, P < 0.001), and their AST levels 52.5±36.21 U/L versus 23.4±4.86 U/L in the controls (95% CI 11.99 – 46.20, P < 0.01). Seventy five percent of the study group had sonar features suggestive of fatty liver disease. Two adipocytokines, adiponectin and leptin, mediators of insulin resistance, an important factor in the development and progression of NAFLD, were also measured. Adiponectin levels were significantly lower (6875 ng/L versus 15475 ng/L; median value, P < 0.01), and leptin concentration levels significantly higher (13.56 ng/L versus 3.05 ng/L; median value, P < 0.05) in the study subjects than in the control group. Alcohol was detected in 60% of the study subjects, of which 35% tested positive for ethanol, 55% tested positive for methanol, and 30% tested positive for both ethanol and methanol. This was a statistically significant result, as none of the control group tested positive for any of the alcohols. The ethanol concentration in the study subjects’ blood was 7.14±3.28 mg% (mean ± SD), in their urine 3.71± 12.87 mg% (mean ± SD) whilst none was detected in their breath. The methanol concentration in the study subjects’ blood was 16.17±17.95 mg% (mean ± SD), in their urine 6.8± 13.58 mg% (mean ± SD) while their breath level was 2.05±3.19 mg (mean ± SD). This study therefore suggests that endogenous alcohol production may be indeed be involved in the pathogenesis of NAFLD in subjects with the metabolic syndrome. Not only ethanol but also methanol was detected in the subjects tested. endogenous alcohol may therefore be responsible for the ‘second hit’ theory in the pathogenesis of NAFLD, and it is likely that formaldehyde, the metabolite of methanol may be a more potent toxin of the patocyte injury as opposed to acetaldehyde, the metabolite of ethanol. The most likely source of the alcohol is from intestinal bacterial flora. These findings provide further insight into the pathogenesis of NALFD, suggesting other therapeutic alternatives such as the use of antibiotics and probiotics as a potential treatment strategy for NAFLD.
The effect of all-trans retinoic acid on the migration of avian neural crest cells in vitro an in vivo
(University of the Witwatersrand, Johannesburg, 2007-02-15T11:43:45Z) Tshabalala, Vincent Abie Thabiso
Retinoic acid, the active metabolite of Vitamin A is known to play a major role in embryonic growth and differentiation during development. It has been shown that either excess or deficiency of retinoic acid during embryogenesis can be teratogenic. In order to study the teratogenic effects of retinoic acid, the aim of the present study was therefore to investigate the effect of all-trans retinoic acid on the migration and fate of neural crest cells in vitro and in vivo. In addition, the study investigated the effect of retinoic acid on the cytoskeletal elements of neural crest cells and on Rac and Rho, two members of the Rho family of GTPases. The neural tubes containing neural crest cells of quail embryos were removed at cranial levels and cultured on fibronectin as a substrate. The neural tubes were cultured in either Dulbecco’s minimal essential medium (DMEM) or in DMEM+Dimethylsulphoxide (DMSO) as controls. In order to test the effect of retinoic acid, the neural tubes were cultured in 10⁻⁵M all-trans retinoic acid (RA) which was reconstituted in DMSO. The distance of migration of the cultured quail neural crest cells was measured and compared between the controls and the experimentals. To study the effect of RA on the cell actin cytoskeleton in vitro, cultured neural crest cells were stained with rhodamine phalloidin. In addition, following 24 hours of culture, the quail neural crest cells were brought into suspension and micro-injected into 36 hour-old chick hosts. While the migration of neural crest cells was extensive in the control cultures in vitro, migration was inhibited in the retinoic acid-treated neural crest cells. In addition, retinoic-acid treated neural crest cells showed pigmentation and neuronal processes earlier than did the control neural crest cells. Retinoic acid-treated neural crest cells showed a disarray of the cytoskeletal elements as they were devoid of stress fibres and focal adhesions. In addition, retinoic acid appears to decrease the expression of Rac and Rho of cultured quail neural crest cells. Following micro-injection of cultured control and RA-treated quail neural crest into the cranial region of chick hosts, the control cells populated the beak area, whereas the retinoic acid-treated quail neural crest cells migrated to the retina of the eye, a region they normally do not populate. These results suggest that retinoic acid disturbs the migration of neural crest cells. It appears to do this by affecting the cytoskeletal elements of neural crest cells and the genes that are involved in forming these elements.
The Impact of Employee Shareholding Option Plans on Company Performance in South Africa
(University of the Witwatersrand, Johannesburg, 2009-07) Motswenyane, Papillon; Ncube, Mthuli
Employee Share Option Plans (ESOPs) are widely applied in the South African context to disseminate wealth to Historically Disadvantaged South Africans (HDSAs). This opinion is affirmed by an increased application of the concept on a number of Broad Based Black Economic Empowerment (BBBEE) transaction deals concluded recently. The research explored the impact of these schemes on company performance and also investigated the resultant economic impact on participating employees. Data was collected from JSE-listed companies that have implemented these schemes over an eight year period between the years 2000 and 2008. Tobin's Q ratios were constructed using data from various sources with annual reports as the primary source of data. An event analysis was undertaken by measuring Tobin's Q of the said companies before and after the implementation of the respective schemes. A secondary process collated data from a survey of employees participating in the schemes to measure their increased productivity and also to ascertain financial employee spin-offs from the schemes. The research found inconclusive evidence that ESOPs impact positively on company performance. However evidence of a strong correlation between potential productivity increases and the schemes was confirmed . Also, a relationship between an employee's level and term of participation to financial reward was established. This research will assist companies in structuring their ESOPs in relation to individual employee contribution to enhance company performance and will also provide guidance on ESOPs financial impact on employees.
Barriers to protection: gender-related persecution and asylum in South Africa
(2009-10-12T12:24:42Z) Middleton, Julie
In 1998, South Africa became the first country to explicitly state within its refugee law that gender related persecution is a binding basis for asylum, further distinguishing South Africa as a state with outstanding legal commitments to gender equality. Creating further visibility within the law, however, is only one step in the process. How the law is implemented determines its real worth and effectiveness. This study assesses the manner in which asylum decisions are made, particularly in cases of gendered harm, questioning readily accepted and essentialised notions of women and gender. It looks at how the South African asylum system defines legitimate refugees, and the interplay of fluid interpretations of gender, culture, violence and the political within these constructions. Through interviews with officials and asylum seekers, the study identifies trends in the refugee system, and interrogates the reliance on narrow understandings of the political and personal, as well as the nature of conflict and culture.
Comparative study of five country-specific labour-intensive infrastructure development programmes : implications for South Africa
(University of the Witwatersrand, Johannesburg, 2010) Quainoo, Harry Akyen; McCutcheon, R.T.
Unemployment and abject poverty in South Africa are widespread, persistent and disproportionately high. These problems are aggravated by inadequate capacity at all tiers of government and huge infrastructure backlogs in rural South Africa. Employment-intensive means of infrastructure delivery have been successfully implemented in several sub-Saharan African countries and elsewhere to generate employment and reduce poverty. It should be possible to replicate similar large-scale national programmes in South Africa. But South Africa has failed. Both prior to and since 1994, several supposedly employment-intensive programmes have been implemented in South Africa with poor results. In an endeavour to contribute to future South African policy and good practices regarding employment, this thesis describes and analyses in detail five major Sub-Saharan programmes and reaches conclusions regarding their achievements and shortcomings. Lessons derived bridge the knowledge gap between the large-scale programmes embarked upon in the sub-Saharan countries in the mid-1980s and the year 2007; these lessons should be applied to future endeavours in South Africa to generate significant employment per unit of expenditure and contribute to poverty alleviation. A major conclusion reached was that the success of employment-intensive infrastructure development programmes depends to a large extent on fundamental factors such as appropriate and implementable policy, government commitment, adequate and sustainable funding, adequate capacity and good preparation. Specifically, the thesis demonstrated that prior to implementation a sufficient timeframe is required for programme preparation in order to make significant contribution towards poverty reduction. Equally, national programme expansion requires a strategic balance between centralisation and decentralisation. In particular, for programme extension and decentralisation, due regard must be given to training and capability building and available resources. Deriving from the thesis’ major conclusions, the author developed three crucially important frameworks for anti-poverty infrastructure development programmes, namely; a four-phased model for evaluating the chances of success of infrastructure programmes, a five-phased result-oriented guidelines for testing the workability of infrastructure development policies, and a practical guideline for monitoring and evaluating employment-creation programmes that maximises the benefits thereof and pre-empts institutional memory loss through systematic knowledge management.
Record review of patients with brain abscess and empyema.
(University of the Witwatersrand, Johannesburg, 2010-01-22T10:28:25Z) Schwenke, Katherine Linda
Studies of patients presenting with brain abscess (BA) and Empyema are not routinely focused on occupational therapy (OT). There is a paucity of literature on deficits other than hemiplegia. Aims of this study were to determine the relationship between BA, Empyema, motor and other deficits and whether an OT intervention protocol is needed. Record review was used to establish clinical presentation trends. Hemiplegia was the most common motor deficit and the majority scored below the norm on the Beery- Buktenika Developmental Test of Visual Motor Integration (VMI). Patients with Brain Abscess generally had more significant deficits than those with Empyema for both motor and process deficits. Part B followed up a small sample (n=8) which indicated clinical improvement on the VMI test with the score on the supplemental test of motor coordination remaining a concern. Occupational Therapy is recommended to address these issues based on the Occupational Therapy Practice Framework-II.
The effect of a scissor skills program on bilateral fine motor skills in preschool children in South Africa including skill improvement, equivalence, transferability of skills and skill retention
(University of the Witwatersrand, Johannesburg, 2010-01-27T12:43:24Z) Ratcliffe, Ingrid
The purpose of this study was to assess the improvement of scissor skills after a graded scissor skills program in preschool children in South Africa (SA). A bilateral fine motor skills assessment tool was developed for use in this research. This task-based assessment included every day activities required at school as well as personal management items. This research phase included the development of the test items and test instructions, scoring as well as validity and reliability testing of the assessment. A suitable scissor skills program was then developed for Grade 0 children in South Africa. The program was validated by a pilot study and also by a focus group of occupational therapists. Some changes were made to the picture selection, the grading of the program, as well as to teacher instructions on how to present the program before it was finalised and ready for use in the implementation phase of the research study. The implementation phase of the study included the individual assessment of 149 learners (mean age of 5 years 6 months), from three different schools in South Africa. The main aim was to establish the effectiveness of the scissor skills program by measuring skill improvement, transferability of skills and skill retention. A further aim was to compare the difference of skill levels of learners from various socio-economic backgrounds in South Africa. The results showed statistically significant improvement in scissor skills in all groups from the three different schools, as well as an ability to retain the learnt skills. Participants from lower socio-economic backgrounds demonstrated the least skill initially but made the greatest gains during the program, at times decreasing the gap between themselves and other participants. It was concluded that children benefited from a graded scissor skills program, which allowed them to improve and retain their scissor skills but improvement did not transfer to other fine motor tasks.
The role of regulatory T cells in adults in South Africa with active tuberculosis
(2010-01-28T10:11:24Z) Mayne, Elizabeth Sarah
Introduction: Regulatory T cells (Tregs) are increasingly being recognized as key immunological players in immunosuppression and have been seen to be permissive for certain infections. Aim: This study aimed to elucidate the role that Tregs play in symptomatic infection with Mycobacterium tuberculosis (TB), both with and without co-infection with human immunodeficiency virus type 1 (HIV 1) by quantification of these cells at ex vivo. It was then attempted to characterise the behaviour of FoxP3 positive cells in culture with stimulation. Methods: Peripheral blood mononuclear cells were purified from uninfected controls, patients with active TB, patients with HIV infection and patients with HIV infection and active TB. The frequencies of Tregs were assessed by flow cytometry at ex vivo and again after four days of culture with stimulation with anti-CD3, Purified protein derivative, tetanus toxoid and HIV peptide superpools (gag and nef). These frequencies were compared between the four groups of patients. The ability of Tregs and effector T cells to proliferate was also assessed. Interferon-γ secretion was used as a measure of effector T cell response to stimulation. vi Results: Frequencies of Tregs were significantly reduced in patients with active TB as compared with HIV infected patients and uninfected controls. Co-infected individuals showed a broad range of frequencies which were not significantly different from controls. These frequencies remained stable in culture with the exception of those individuals infected with HIV who showed a decline in the frequency of those cells expressing FoxP3 over the period. Cells expressing FoxP3 were not anergic and responded to stimulation. HIV specific proteins, in addition, resulted in specific effects on the Tregs with a positive interferon response to gag correlating with increased Treg frequencies and FoxP3 expression in CD4+ T cells correlated with the proliferative response of CD4+ T cells to Nef in HIV infected individuals. Conclusions: This study shows significant differences of frequencies of FoxP3 positive producing cells in the peripheral blood at ex vivo in patients with active TB. The function of these cells in this population is uncertain and further functional data and long-term clinical follow-up is required. In addition, the frequencies of these cells remained constant over time and showed proliferative response to stimuli (most notably CD3) suggesting that these cells may be generated in the periphery.
The impact of lower limb amputation on quality of life: a study done in the Johannesburg Metropolitan area, South Africa
(University of the Witwatersrand, Johannesburg, 2010-01-29T07:15:06Z) Godlwana, Lonwabo L.
Background: The impact of non-traumatic lower limb amputation on participant’s quality of life (QOL) is unknown. In an effort to provide better care for people with lower limb amputation, there is a need to first know the impact of this body changing operation on people’s quality of life. Aim of the study: To determine the impact of lower limb amputation on QOL in people in the Johannesburg metropolitan area during their reintegration to their society/community of origin. Objectives: 1. To establish the pre-operative and post-operative:  QOL of participants (including the feelings, experiences and impact of lower limb amputation during the time when they have returned home and to the community).  The functional status of participants.  Household economic and social status of these participants. 2. To establish factors influencing QOL. Methods: A longitudinal pre (amputation) test –post (amputation) test study utilized a combination of interviews to collect quantitative data and in-depth semi-structured interviews to gather qualitative data. Consecutive sampling was used to draw participants (n=73) for the interviews at the study sites pre-operatively. The three study sites were Chris Hani Baragwanath Hospital, Charlotte Maxeke Johannesburg General Hospital and Helen Joseph Hospital. Participants were then followed up three months later for post-operative interviews and key informants were selected for in-depth interviews (n=12). Inclusion criteria: Participants were included if they were scheduled for first time unilateral (or bilateral amputation done at the same time) lower limb amputation. The participants were between the ages of 36-71 years. Exclusion criteria: Participants who had an amputation as a result of traumatic or congenital birth defects were excluded from the study. Participants with comorbidities that interfered with function pre-operatively were not included. Procedures: Ethics: Ethical clearance was obtained from the Committee for Research on Human Subjects at the University of the Witwatersrand and permission was obtained from the above hospitals. Participants gave consent before taking part in the study. Instrumentation: A demographic questionnaire, the EQ-5D, the Modified Household Economic and Social Status Index (HESSI), the Barthel Index (BI) and semi-structured in-depth interviews were used. Data collection: Participants were approached before the operation for their preoperative interviews using the above questionnaires and then followed up postoperatively using the same questionnaires and some were selected to participate in semi-structured in-depth interviews three months later. Pilot study: The demographics questionnaire and the modified HESSI were piloted to ensure validity and reliability. iii Data analysis: Data were analyzed using the SPSS Version 17.0 and STATA 10.0. The significance of the study was set at p=0.05. All continuous data are presented as means, medians, standard deviations and confidence intervals (CI 95%). Categorical data are presented as frequencies. Pre and post operative differences were analyzed using Wilcoxon Signed-rank test. A median regression analysis (both the univariate and multivariate regression) was done to establish factors influencing QOL. Pre and post operative differences in the EQ-5D items and the BI items were analyzed using Chi square/Fischer’s exact depending on the data. Data were pooled for presentation as statistical figures in tables. Both an intension to treat analysis and per protocol analysis were used. A grounded theory approach was used to analyze the concepts, categories and themes that emerged in the qualitative data. Results: Twenty-four participants (33%) had died by the time of follow up. At three months, n=9 (12%) had been lost to follow up and 40(55%) was successfully followed up. The preoperative median VAS was 60 (n=40). The postoperative median VAS was 70. The EQ-5D items on mobility and usual activities were reported as having deteriorated significantly postoperatively (p=0.04, p=0.001respectively) while pain/discomfort had improved (p=0.003). There was no improvement in QOL median VAS from the preoperative status to three months postoperatively The preoperative median total BI score was (n=40). The postoperative median total BI score was 19. There was a reduction in function (median BI) from the preoperative status to three months postoperatively (p<0.001). The ability to transfer was improved three months postoperatively (p=0.04). Participants were also found to have a decreased ability to negotiate stairs (p<0.001). Mobility was significantly reduced three months postoperatively (p=0.04). During the postoperative stage (n=40), 38% of the participants were married. Most (53%) of the participants had no form of income. The highest percentage of participants in all instances (35%) had secondary education (grade10-11), while 25% had less than grade 5. Only one participant was homeless, 18% lived in shacks, 55% lived in homes that were not shared with other families. People with LLA in the Johannesburg metropolitan area who had no problem with mobility preoperatively (EQ-5D mobility item), who were independent with mobility (BI mobility item) preoperatively, who were independent with transfer preoperatively (BI transfer item) had a higher postoperative quality of life (postoperative median EQ-5D- VAS) compared to people who were dependent or had problems with these functions preoperatively. Being females was a predictor of higher reported quality of life compared to being male. Emerging themes from the qualitative data were psychological, social and religious themes. Suicidal thoughts, dependence, poor acceptance, public perception about body image, phantom limb related falls and hoping to get a prosthesis were reported. Some reported poor social involvement due to mobility problems, employment concerns, while families and friends were found to be supportive. Participants had faith in God. Conclusion: Participants’ QOL and function were generally scored high both preoperatively and postoperatively but there was a significant improvement in QOL and a significant reduction in function after three months although participants were generally still functionally independent. Good mobility preoperatively is a predictor of good QOL postoperatively compared to people with a poor preoperative mobility status. Generally, most participants had come to terms with the amputation and were managing well while some expressed that they were struggling with reintegration to their community of origin three months postoperatively with both functional and psychosocial challenges.
Sex and age related distinctions in the feeding ecology of the African elephant
(2010-01-29T08:19:33Z) Greyling, Michelle Deborah
Understanding intimate femicide in South Africa
(2010-09-22) Mathews, Shanaaz
When a woman is killed she is most likely to be murdered by an intimate partner. This form of homicide known as intimate femicide is conceptualised to be the most extreme consequence of intimate partner violence. Not much is known about such killings in South Africa or in other developing settings. This thesis studied intimate femicide using two complimentary studies from two methodological perspectives. The first study was quantitative with the aim of describing the incidence and pattern of intimate femicide in South Africa. The second study used qualitative methods and explored the social construction of the early formation of violent masculinities. Five papers written from these two studies are presented in this thesis. Study one was a retrospective national mortuary-based study and collected data on all female homicides, 14 years and older, who died in 1999 from a stratified, multi-stage sample of 25 mortuaries. Data was collected from the mortuary file, autopsy report, and a police interview. The second study used a cluster of qualitative in-depth interviews with 20 incarcerated men in prison who have been convicted for the murder of an intimate partner, as well as interviews with family and friends of both the perpetrator and the victim. Overall it was found that 50.3% of women murdered in South Africa are killed by an intimate partner, with an intimate femicide rate of 8.8/100 000 and an intimate-femicide suicide rate of 1.7/100 000 females 14 years and older. Blunt force injuries were shown to be associated with intimate killings, while gun ownership was associated with intimate femicide-suicides. vi elevated Blood Alcohol Concentration (BAC) combined with unemployed status was also found to be associated with intimate killings. The qualitative study showed that traumatic childhood experiences such as violent and neglectful parenting practises particularly by mothers made these men feel unloved, inferior and powerless with this found to be a pathway to violent models of masculinity used as a means to attain power and respect. This study shows that such traumatic experiences can lead to a suppression of emotions. It is argued that cognitive dissonance act as a protective mechanism which allows these men to perpetrate acts of violence without consideration of its impact. These findings suggests that intimate femicide is a complex phenomenon with a “web” of associated and mediating factors which all contribute to it excessive levels in South Africa. It shows that intimate femicide is an extension of intimate partner violence and as such has to take into account the unequal gender relations in society. Building gender equity and shifting patterns of femininity and masculinity is a key strategy in reducing this form of violence.
Levels and factors associated with homicide-related deaths in a rural South African population
(2011-03-25) Otieno, George Omondi
Background: World Health Organization (WHO) estimates that more than 1.6 million people die every year because of violence and out of these deaths, homicide accounts for almost one third. Ninety percent (90%) of homicide are thought to occur in low and middle income countries. South Africa has one of the most disturbing rates of homicide in the world. These high homicide rates besides resulting in reduced life expectancy also have serious health, social and economic consequences. Aim: The study aimed at quantifying the burden as well as and identifying factors associated with homicide deaths in rural KwaZulu-Natal in South Africa during the period of 2000 to 2008. Objectives: To estimate a 9 year period (2000-2008) homicide incidence rates as well as identify factors associated with homicide-related deaths. Further, the analysis described spatial distribution of homicide-related deaths in a rural South African population. Design: Analytical longitudinal study. Methods: Using data drawn from the Verbal Autopsies (VAs) conducted on all deaths recorded during annual demographic and health surveillance over a 9-year period (2000-2008), Kaplan-Meier (K-M) survival estimates of incidence rates were used to estimate the cumulative probability of death until the end of the period. Estimates were reported by sex and residency. Weibull regression methods were used to investigate factor associated with homicide deaths. Kulldorff spatial scan statistics was used to describe homicide clustering. Results: With 536 homicide-related deaths, and 814, 715 total Person Years of contribution, the study found an overall incidence rate of 66 (95% CI= (60, 72) per 100, 000 Person Years of v Observation (PYOs) for the period studied. Death due to firearm was reported the leading cause of mortality (65%). Most deaths occurred over the weekends (43%), followed by Friday (16.2%).The highest homicide incidence rates were recorded in 2001 (90; 95% CI= (71, 111) per 100,000 person years at risk and 2004 (86; 95% CI= (68, 108) per 100,000 person years at risk. Males had a rate that was about six times more than females 115 (95% CI=105,127) per 100,000 PYOs. Age-specific homicide rate were highest among males aged 25-29 years (209.90 per 100,000 PYOs) and females aged 50-54 years (78 per 100,000 PYOs). Resident, age, sex, education, socioeconomic status, and employment independently predicted homicide risk. The study identified two geographical clusters with significantly elevated homicide risk. Conclusion: A significant six fold difference in homicide rate existed between males and females. Sex differential increases with age, with males aged 15-54 years the most likely to be killed, and females aged 55 years and above having the highest homicide rate. Increase in wealth status and level of education increases one‘s risk of homicide. Employment per se was protective from homicide risk. Firearm was the leading cause of mortality. Most deaths occur over the weekend. Two geographical areas with elevated homicide risk were observed. These findings underscore the need to have timely information and strategies for effective violence prevention program to subgroups and areas at risk.

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