4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
Permanent URI for this communityhttps://hdl.handle.net/10539/37773
Browse
4 results
Search Results
Item The Impact of Employee Shareholding Option Plans on Company Performance in South Africa(University of the Witwatersrand, Johannesburg, 2009-07) Motswenyane, Papillon; Ncube, MthuliEmployee 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.Item Barriers to protection: gender-related persecution and asylum in South Africa(2009-10-12T12:24:42Z) Middleton, JulieIn 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.Item 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, DerickNon-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.Item 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 ThabisoRetinoic 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.