The identification of the UV degradants of melatonin and their ability to scavenge free radicals
- Maharaj, Deepa S, Anoopkumar-Dukie, Shailendra, Glass, Beverley D, Antunes, Edith M, Lack, Barbara A, Walker, Roderick B, Daya, Santylal
- Authors: Maharaj, Deepa S , Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Antunes, Edith M , Lack, Barbara A , Walker, Roderick B , Daya, Santylal
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184303 , vital:44198 , xlink:href="https://doi.org/10.1034/j.1600-079X.2002.01866.x"
- Description: Ultraviolet (UV) light is known to induce the generation of free radicals in biological tissues such as skin. Of these free radicals, the O2–· and particularly the ·OH radical can induce cellular damage including lipid peroxidation. Thus, the use of antioxidants to prevent such damage induced by UV irradiation has received much attention recently. One such antioxidant, which has the potential to be incorporated into sunscreens, is the pineal secretory product melatonin. One of the concerns of using melatonin in sunscreens is its photostability. In the present study, we investigated the photostability of melatonin subjected to UV irradiation. In addition, we used liquid chromatography mass spectrometry (LC-MS) to identify the degradants and we also assessed the ability of the degradants to inhibit O2–· generation as well as lipid peroxidation in rat brain homogenate. The results show that UV irradiation of melatonin (0.1 mg/mL) using a 400-W lamp for 2 hr caused a significant decline of melatonin to 18% of its original concentration after 20 min, with the decline continuing until the melatonin concentration reaches zero at 120 min. The LC-MS results show that the degradants of melatonin are 6-hydroxymelatonin and N1-acetyl-N2-formyl-5-methoxykynurenamine (AFMK). These degradants were able to provide equipotent activity against potassium cyanide (KCN)-induced superoxide generation compared to non-irradiated melatonin. Thus, the study shows that although melatonin is rapidly degraded by UV irradiation, the degradants retain antioxidant activity, making melatonin a likely candidate for inclusion in sunscreens.
- Full Text:
- Date Issued: 2002
- Authors: Maharaj, Deepa S , Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Antunes, Edith M , Lack, Barbara A , Walker, Roderick B , Daya, Santylal
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184303 , vital:44198 , xlink:href="https://doi.org/10.1034/j.1600-079X.2002.01866.x"
- Description: Ultraviolet (UV) light is known to induce the generation of free radicals in biological tissues such as skin. Of these free radicals, the O2–· and particularly the ·OH radical can induce cellular damage including lipid peroxidation. Thus, the use of antioxidants to prevent such damage induced by UV irradiation has received much attention recently. One such antioxidant, which has the potential to be incorporated into sunscreens, is the pineal secretory product melatonin. One of the concerns of using melatonin in sunscreens is its photostability. In the present study, we investigated the photostability of melatonin subjected to UV irradiation. In addition, we used liquid chromatography mass spectrometry (LC-MS) to identify the degradants and we also assessed the ability of the degradants to inhibit O2–· generation as well as lipid peroxidation in rat brain homogenate. The results show that UV irradiation of melatonin (0.1 mg/mL) using a 400-W lamp for 2 hr caused a significant decline of melatonin to 18% of its original concentration after 20 min, with the decline continuing until the melatonin concentration reaches zero at 120 min. The LC-MS results show that the degradants of melatonin are 6-hydroxymelatonin and N1-acetyl-N2-formyl-5-methoxykynurenamine (AFMK). These degradants were able to provide equipotent activity against potassium cyanide (KCN)-induced superoxide generation compared to non-irradiated melatonin. Thus, the study shows that although melatonin is rapidly degraded by UV irradiation, the degradants retain antioxidant activity, making melatonin a likely candidate for inclusion in sunscreens.
- Full Text:
- Date Issued: 2002
The immobilization of Microcystis aeruginosa PCC7806 on a membrane nutrient-gradostat bioreacator for the production of the secondary metobolites
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
- Full Text:
- Date Issued: 2002
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
- Full Text:
- Date Issued: 2002
The impact of media commercialisation on programming: a study of Radio Uganda
- Lwanga, Margaret Jjuuko Nassuna
- Authors: Lwanga, Margaret Jjuuko Nassuna
- Date: 2002
- Subjects: Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3453 , http://hdl.handle.net/10962/d1002907 , Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Description: The 1980s and 1990s saw two major changes in the political economy of the media and the world economy at large: technological advancement and transfer and privatisation. There were significant shifts in media industries: newspapers, broadcasting, cinema and telecommunications when governments begun re-regulating their air waves so as to permit private satellite transmission via both encryption and free-to-air, in addition to public service and private channels. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study set out to determine the extent to which commercialisation, in the era of liberalisation and commercialisation of media services in Uganda, has affected Radio Uganda’s programming. Using a combination of qualitative and quantitative methods of investigation, I have established that while Radio Uganda still maintains certain public service principles and values, programming policy has increasingly been changed by commercial considerations. This is shown by the recent rise of commercial programmes and a fall in education and developmental programmes. Limitations of finance and other resources have compromised the roles and character of public service radio programming. The majority of programmes currently on Radio Uganda are evidently geared to attract advertisers rather than serve the public interest. The study recommends, among other measures, that the licence fee be developed as a source of revenue for Radio Uganda. Secondly, government should inject more funding into public service broadcasting institutions to supplement other sources of income, before granting them autonomy. Thirdly, while advertising and sponsorship brings in a considerable amount of revenue, it should not take a central place that undermines the listener’s interest in radio programming. The Broadcasting Council should therefore map out solid policies that will systematically guide Radio Uganda in its programming in the new order.
- Full Text:
- Date Issued: 2002
- Authors: Lwanga, Margaret Jjuuko Nassuna
- Date: 2002
- Subjects: Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3453 , http://hdl.handle.net/10962/d1002907 , Radio programs -- Uganda , Radio Uganda , Public radio -- Uganda
- Description: The 1980s and 1990s saw two major changes in the political economy of the media and the world economy at large: technological advancement and transfer and privatisation. There were significant shifts in media industries: newspapers, broadcasting, cinema and telecommunications when governments begun re-regulating their air waves so as to permit private satellite transmission via both encryption and free-to-air, in addition to public service and private channels. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study set out to determine the extent to which commercialisation, in the era of liberalisation and commercialisation of media services in Uganda, has affected Radio Uganda’s programming. Using a combination of qualitative and quantitative methods of investigation, I have established that while Radio Uganda still maintains certain public service principles and values, programming policy has increasingly been changed by commercial considerations. This is shown by the recent rise of commercial programmes and a fall in education and developmental programmes. Limitations of finance and other resources have compromised the roles and character of public service radio programming. The majority of programmes currently on Radio Uganda are evidently geared to attract advertisers rather than serve the public interest. The study recommends, among other measures, that the licence fee be developed as a source of revenue for Radio Uganda. Secondly, government should inject more funding into public service broadcasting institutions to supplement other sources of income, before granting them autonomy. Thirdly, while advertising and sponsorship brings in a considerable amount of revenue, it should not take a central place that undermines the listener’s interest in radio programming. The Broadcasting Council should therefore map out solid policies that will systematically guide Radio Uganda in its programming in the new order.
- Full Text:
- Date Issued: 2002
The impact of multi-skilling training on the paintshop production environment and its employees at Volkswagen South Africa (VWSA)
- Authors: Bhika, Chandrika
- Date: 2002
- Subjects: Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10852 , http://hdl.handle.net/10948/130 , Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Description: Global competition and rapid technological change have been the driving forces for a more flexible and competent workforce. Continuous employee training assists organisations to achieve their goals by adding value to their key resources, the human factor. The demand for a more qualified workforce becomes a strategic force in the effort to raise competitiveness. Providing, obtaining and improving the necessary skills are important in responding to a rapidly changing international economy. Life-long learning and continuous skills development are the new requirements imposed by our knowledgeintensive society. The overall purpose of the research was to determine the impact of multi-skilling training (MST) on the paintshop production environment and its employees at Volkswagen South Africa (VWSA). The objectives of this research were to: Identify the elements of multi-skilling training and guidelines for its development and implementation; Critically evaluate the current system; Determine the impact of multi-skilling training on the production environment in the paint shop at VWSA The research methodology for this study comprised the following steps: Firstly, the development and implementation of MST at Volkswagen South Africa was assessed. The elements of MST and its impact on production and the employee worldwide were determined through the literature study. Secondly, the limitations of the current MST system used in the paintshop at Volkswagen South Africa were assessed in an empirical study, which involved completing of questionnaires. The empirical study proved that the current MST system employed in the paintshop at Volkswagen South Africa had assisted in improving production, and increasing the employees’ morale. The final step of this study entailed the formulation of recommendations, which are as follows: · Sufficient time should be allocated for practical training. · Frequent job rotation must be implement ed. · Advanced MST must be implemented after completion of Level Four. · MST should be presented in English, Afrikaans and Xhosa.
- Full Text:
- Date Issued: 2002
- Authors: Bhika, Chandrika
- Date: 2002
- Subjects: Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10852 , http://hdl.handle.net/10948/130 , Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Description: Global competition and rapid technological change have been the driving forces for a more flexible and competent workforce. Continuous employee training assists organisations to achieve their goals by adding value to their key resources, the human factor. The demand for a more qualified workforce becomes a strategic force in the effort to raise competitiveness. Providing, obtaining and improving the necessary skills are important in responding to a rapidly changing international economy. Life-long learning and continuous skills development are the new requirements imposed by our knowledgeintensive society. The overall purpose of the research was to determine the impact of multi-skilling training (MST) on the paintshop production environment and its employees at Volkswagen South Africa (VWSA). The objectives of this research were to: Identify the elements of multi-skilling training and guidelines for its development and implementation; Critically evaluate the current system; Determine the impact of multi-skilling training on the production environment in the paint shop at VWSA The research methodology for this study comprised the following steps: Firstly, the development and implementation of MST at Volkswagen South Africa was assessed. The elements of MST and its impact on production and the employee worldwide were determined through the literature study. Secondly, the limitations of the current MST system used in the paintshop at Volkswagen South Africa were assessed in an empirical study, which involved completing of questionnaires. The empirical study proved that the current MST system employed in the paintshop at Volkswagen South Africa had assisted in improving production, and increasing the employees’ morale. The final step of this study entailed the formulation of recommendations, which are as follows: · Sufficient time should be allocated for practical training. · Frequent job rotation must be implement ed. · Advanced MST must be implemented after completion of Level Four. · MST should be presented in English, Afrikaans and Xhosa.
- Full Text:
- Date Issued: 2002
The implementation of environmental education policy in Namibia: perceptions of a range of decision-makers
- Authors: Katoma, Loini-Nyanyukweni
- Date: 2002
- Subjects: Environmental education -- Namibia , Education and state -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1563 , http://hdl.handle.net/10962/d1003445 , Environmental education -- Namibia , Education and state -- Namibia
- Description: This study is the first cycle of an action research project that focuses on the implementation of the Environmental Education Policy in Namibia. Perceptions of Namibian decision-makers were sought with regard to their understanding of the concepts ‘environment’ and ‘environmental education’, as well as to identify environmental problems and obstacles to the implementation of the Environmental Education Policy. The approach of coming up with options to address the identified problems/obstacles/constraints, was employed in this study. To this effect, interviews, a workshop, observations and reflections on the process of implementation resulted in a wealth of data. The findings shed light on possible solutions to address the identified problems and obstacles. The results revealed that community participation, skills development and the proper co-ordination of environmental education activities are imperative in addressing the obvious policy-practice gap. Decision-makers uncovered the fact that the socio-economic situation of our people necessitated pulling our resources together and working as a team. The overall perceptions are that the environment is everyone’s business and that we should zealously use it and carefully guard it, not only for ourselves but also, for the benefit of coming generations.
- Full Text:
- Date Issued: 2002
- Authors: Katoma, Loini-Nyanyukweni
- Date: 2002
- Subjects: Environmental education -- Namibia , Education and state -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1563 , http://hdl.handle.net/10962/d1003445 , Environmental education -- Namibia , Education and state -- Namibia
- Description: This study is the first cycle of an action research project that focuses on the implementation of the Environmental Education Policy in Namibia. Perceptions of Namibian decision-makers were sought with regard to their understanding of the concepts ‘environment’ and ‘environmental education’, as well as to identify environmental problems and obstacles to the implementation of the Environmental Education Policy. The approach of coming up with options to address the identified problems/obstacles/constraints, was employed in this study. To this effect, interviews, a workshop, observations and reflections on the process of implementation resulted in a wealth of data. The findings shed light on possible solutions to address the identified problems and obstacles. The results revealed that community participation, skills development and the proper co-ordination of environmental education activities are imperative in addressing the obvious policy-practice gap. Decision-makers uncovered the fact that the socio-economic situation of our people necessitated pulling our resources together and working as a team. The overall perceptions are that the environment is everyone’s business and that we should zealously use it and carefully guard it, not only for ourselves but also, for the benefit of coming generations.
- Full Text:
- Date Issued: 2002
The independent high rate algal pond as a unit operation in tertiary wastewater treatment
- Authors: Clark, Stewart James
- Date: 2002
- Subjects: Algae -- Biotechnology , Sewage -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4092 , http://hdl.handle.net/10962/d1007805
- Description: The development of the High Rate Algal Pond (HRAP) as an independent tertiary treatment unit operation for phosphate and nitrate removal is reported. A novel Integrated Algal Ponding System (lAPS) design is proposed for nutrient removal from the effluents of both a conventional domestic sewage treatment plant and from an Advanced Integrated Wastewater Ponding System (AIWPS). The viability of an independently operated HRAP has been identified and termed the Independent High Rate Algal Pond (l-HRAP). A 500 m² pilot 1- HRAP was operated in such a way as to facilitate the precipitation of calcium phosphate, known to be controlled by pH (greater than 9.4) and resulting in final phosphate levels of less than 1 mg.L⁻¹ as P0₄-P. The incorporation of the I-HRAP into a denitrification process was also investigated. Continuously fed column reactors, utilising algal biomass as a carbon source, showed that the heterotrophic bacterial community dominant in the anaerobic algal sludge were denitrifying the nitrate in the feed. It was demonstrated that as the cultures were stressed (using increased nitrate concentrations, anaerobiosis and light starvation) total polysaccharide (TPS) concentrations increased, with a notable increase 111 the exopolysaccharide (EPS) fraction. These experiments corroborated the hypothesis that harvested microalgal biomass can be manipulated to produce, and release, exopolymeric substances under stress conditions, and which may serve as carbon source for denitrification. In both batch flask studies and in laboratory-scale reactor systems, harvested microalgal biomass from an HRAP was shown to produce exopolymeric substances under stress conditions. Initial high loading-rates of greater than 20 mg.L⁻¹ NO₃-N resulted in double the amount of exopolysaccharide production than in flasks with initial low loading-rates (less than 5 mg.L⁻¹ NO₃-N). Making use of an upflow anaerobic sludge blanket-type degrading-bed reactor, and an anaerobic, flooded trickle filter (ANTRIC) receiving HRAP effluent, the relationship between denitrification and the changes in polysaccharide content was investigated. This phenomenon has considerable beneficial implications in biological wastewater treatment systems where high nitrate concentration in the final effluent is a potential mitigating factor. Identification of the heterotrophic bacteria active in the denitrification process was attempted. This study presents a first report on the development and operation of the I-HRAP and has been followed by a technical-scale pilot plant evaluation of the process in the tertiary treatment of domestic wastewaters.
- Full Text:
- Date Issued: 2002
- Authors: Clark, Stewart James
- Date: 2002
- Subjects: Algae -- Biotechnology , Sewage -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4092 , http://hdl.handle.net/10962/d1007805
- Description: The development of the High Rate Algal Pond (HRAP) as an independent tertiary treatment unit operation for phosphate and nitrate removal is reported. A novel Integrated Algal Ponding System (lAPS) design is proposed for nutrient removal from the effluents of both a conventional domestic sewage treatment plant and from an Advanced Integrated Wastewater Ponding System (AIWPS). The viability of an independently operated HRAP has been identified and termed the Independent High Rate Algal Pond (l-HRAP). A 500 m² pilot 1- HRAP was operated in such a way as to facilitate the precipitation of calcium phosphate, known to be controlled by pH (greater than 9.4) and resulting in final phosphate levels of less than 1 mg.L⁻¹ as P0₄-P. The incorporation of the I-HRAP into a denitrification process was also investigated. Continuously fed column reactors, utilising algal biomass as a carbon source, showed that the heterotrophic bacterial community dominant in the anaerobic algal sludge were denitrifying the nitrate in the feed. It was demonstrated that as the cultures were stressed (using increased nitrate concentrations, anaerobiosis and light starvation) total polysaccharide (TPS) concentrations increased, with a notable increase 111 the exopolysaccharide (EPS) fraction. These experiments corroborated the hypothesis that harvested microalgal biomass can be manipulated to produce, and release, exopolymeric substances under stress conditions, and which may serve as carbon source for denitrification. In both batch flask studies and in laboratory-scale reactor systems, harvested microalgal biomass from an HRAP was shown to produce exopolymeric substances under stress conditions. Initial high loading-rates of greater than 20 mg.L⁻¹ NO₃-N resulted in double the amount of exopolysaccharide production than in flasks with initial low loading-rates (less than 5 mg.L⁻¹ NO₃-N). Making use of an upflow anaerobic sludge blanket-type degrading-bed reactor, and an anaerobic, flooded trickle filter (ANTRIC) receiving HRAP effluent, the relationship between denitrification and the changes in polysaccharide content was investigated. This phenomenon has considerable beneficial implications in biological wastewater treatment systems where high nitrate concentration in the final effluent is a potential mitigating factor. Identification of the heterotrophic bacteria active in the denitrification process was attempted. This study presents a first report on the development and operation of the I-HRAP and has been followed by a technical-scale pilot plant evaluation of the process in the tertiary treatment of domestic wastewaters.
- Full Text:
- Date Issued: 2002
The influence of structure, density and direct use benefits on the harvesting of trees in the rural village of Pikoi, Eastern Cape, South Africa
- Authors: Motinyane, Teboho R
- Date: 2002
- Subjects: Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4771 , http://hdl.handle.net/10962/d1007705 , Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Description: The people of Pikoli in the Peddie district of the Eastern Cape are mostly unemployed and earn most of their income from old-age allowances. The place is remote and 'modern' amenities such as paraffin and petroleum gas are expensive. Electricity and transport are unavailable. There is heavy reliance on woody plants for fuel and for materials for construction and fencing and to some extent medicinal and ritual uses. Indigenous trees in this rural area are threatened by over-utilisation and the absence of clear government management policies. The over-utilisation of these resources is leading to deforestation. It was proposed at the beginning of this study that people who harvest trees cause similar results to the piosphere effect caused by the herbivores on the rangeland. Ecological-economic analysis was performed to find a common ground between the people's income and needs so that effective sustainable management strategies can be developed. A combination of semi-structured interviews, direct observations and ecological surveys were used to gather information about: Tree species used, and for what purpose in Pikoli; Individual tree species preference by inhabitants; Change in tree density in response to changes in utilisation intensity at varying distances away from the village; The local direct use benefits inhabitants derive from utilising indigenous tree resources. The study showed that the people of Pikoli use a variety of 23 indigenous trees and that they have marked preferences regarding the tree species they use for fuelwood and construction purposes. Although Ptaeroxylon obliquum is a highly preferred species for fuelwood and construction, its popularity can also be linked to its high relative abundance in this area. Other species such Maytenus undata and Pappea capensis are also highly preferred although they are harvested at much greater distances from thecentre of the village. Change in individual tree density in response to changes in utilisation intensity at varying distances away from the village showed clearly that a piosphere effect also applies to human harvesting. The average number of individual trees closer (1 200 m) to the village centre was 2 trees per 100 m², and their numbers increase to approximately 35 trees per 100 m² at a distance of about 3 000 m from the village centre. The study reports on the direct use benefits derived by the people of Pikoli from harvesting tree resources. The average total net value of trees harvested for fuelwood was R4089.09 (US$ 359.01) per household per annum. The value of tree resources harvested represents a large percentage of average households' annual income. Therefore, the economic benefits households derive from utilising tree resources are high. Indigenous tree resource use in this rural village seems to be unsustainable and the inhabitants seem to be aware of it. However, they have few alternatives. Their economic conditions do not allow them to afford alternative resources available in the formal market.
- Full Text:
- Date Issued: 2002
- Authors: Motinyane, Teboho R
- Date: 2002
- Subjects: Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4771 , http://hdl.handle.net/10962/d1007705 , Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Description: The people of Pikoli in the Peddie district of the Eastern Cape are mostly unemployed and earn most of their income from old-age allowances. The place is remote and 'modern' amenities such as paraffin and petroleum gas are expensive. Electricity and transport are unavailable. There is heavy reliance on woody plants for fuel and for materials for construction and fencing and to some extent medicinal and ritual uses. Indigenous trees in this rural area are threatened by over-utilisation and the absence of clear government management policies. The over-utilisation of these resources is leading to deforestation. It was proposed at the beginning of this study that people who harvest trees cause similar results to the piosphere effect caused by the herbivores on the rangeland. Ecological-economic analysis was performed to find a common ground between the people's income and needs so that effective sustainable management strategies can be developed. A combination of semi-structured interviews, direct observations and ecological surveys were used to gather information about: Tree species used, and for what purpose in Pikoli; Individual tree species preference by inhabitants; Change in tree density in response to changes in utilisation intensity at varying distances away from the village; The local direct use benefits inhabitants derive from utilising indigenous tree resources. The study showed that the people of Pikoli use a variety of 23 indigenous trees and that they have marked preferences regarding the tree species they use for fuelwood and construction purposes. Although Ptaeroxylon obliquum is a highly preferred species for fuelwood and construction, its popularity can also be linked to its high relative abundance in this area. Other species such Maytenus undata and Pappea capensis are also highly preferred although they are harvested at much greater distances from thecentre of the village. Change in individual tree density in response to changes in utilisation intensity at varying distances away from the village showed clearly that a piosphere effect also applies to human harvesting. The average number of individual trees closer (1 200 m) to the village centre was 2 trees per 100 m², and their numbers increase to approximately 35 trees per 100 m² at a distance of about 3 000 m from the village centre. The study reports on the direct use benefits derived by the people of Pikoli from harvesting tree resources. The average total net value of trees harvested for fuelwood was R4089.09 (US$ 359.01) per household per annum. The value of tree resources harvested represents a large percentage of average households' annual income. Therefore, the economic benefits households derive from utilising tree resources are high. Indigenous tree resource use in this rural village seems to be unsustainable and the inhabitants seem to be aware of it. However, they have few alternatives. Their economic conditions do not allow them to afford alternative resources available in the formal market.
- Full Text:
- Date Issued: 2002
The investigation of the hydrolysis reaction of m-phenylene to resorcinol
- Authors: Khaile, Thebeeapelo John
- Date: 2002
- Subjects: Resorcinol
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10961 , http://hdl.handle.net/10948/107 , Resorcinol
- Description: The purpose of this study was to characterise the resinous material formed during the acid catalysed hydrolysis of m-phenylenediamine (MPDA) to resorcinol, and to establish a reaction mechanism that could explain the formation of both resorcinol and the resinous materials in the reaction. A further objective was to determine reaction conditions that would lead to reduced formation of the resins during the hydrolysis reaction. The number of compounds present in a sample taken during the course of the hydrolysis reaction was determined by HPLC fitted with a photodiode array detector. Five main components were detected. These compounds were identified as mphenylenediamine, m-aminophenol, resorcinol, 3,3’-aminodiphenylamine and 3- amino-3’-hydroxydiphenylamine by means of GC-MS. 3,3’-Diaminodiphenylamine is formed by self-condensation of MPDA and 3-amino-3’-hydroxydiphenylamine is formed by the reaction of MPDA with resorcinol. The degree of formation of these intermediates is substantially reduced when MPDA is added dose-wise to phosphoric acid at a reaction temperature of 220oC. The reaction mechanism of the hydrolysis reaction was investigated by isotopic lable incorporation, followed by analysis by NMR. This was done by hydrolysing MPDA using deuterated phosphoric acid (D3PO4). D3PO4 was generated by dissolving phosphorus pentoxide in deuterium oxide. The resorcinol product obtained from the hydrolysis using D3PO4 was found to be deuterated on the C-2, C-4 and C-6 positions. This suggests that the hydrolysis reaction involves protonation of MPDA on these positions, and this results in the formation of an iminium ion as one of the resonance forms. Hydrolysis then occurs on the positively charged carbon of this species. Fertiliser grade phosphoric acid can be used in the hydrolysis reaction, provided sulphates are removed before the acid is used in the hydrolysis reaction. The hydrolysis reaction using either ammonium sulphate or sulphuric acid produces resorcinol in yields lower than 60% if the hydrolysis is conducted in one pass. If these catalysts are used in the hydrolysis reaction, the reaction mixture needs to be re-heated after removal of resorcinol in order to increase the yield. Hydrolysis of MPDA using zirconium phosphate as catalyst gave resorcinol yields in excess of 90% over 24 hours. These reactions were carried out at very low concentrations of MPDA (0.3%). The mode of catalysis in these reactions is unclear. There is a possibility that the reaction is catalysed by phosphoric acid that leaches out of zirconium phosphate at high temperatures. The reaction might therefore not differ mechanistically from the phosphoric acid catalysed reaction. Further studies are required to clarify this point.
- Full Text:
- Date Issued: 2002
- Authors: Khaile, Thebeeapelo John
- Date: 2002
- Subjects: Resorcinol
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10961 , http://hdl.handle.net/10948/107 , Resorcinol
- Description: The purpose of this study was to characterise the resinous material formed during the acid catalysed hydrolysis of m-phenylenediamine (MPDA) to resorcinol, and to establish a reaction mechanism that could explain the formation of both resorcinol and the resinous materials in the reaction. A further objective was to determine reaction conditions that would lead to reduced formation of the resins during the hydrolysis reaction. The number of compounds present in a sample taken during the course of the hydrolysis reaction was determined by HPLC fitted with a photodiode array detector. Five main components were detected. These compounds were identified as mphenylenediamine, m-aminophenol, resorcinol, 3,3’-aminodiphenylamine and 3- amino-3’-hydroxydiphenylamine by means of GC-MS. 3,3’-Diaminodiphenylamine is formed by self-condensation of MPDA and 3-amino-3’-hydroxydiphenylamine is formed by the reaction of MPDA with resorcinol. The degree of formation of these intermediates is substantially reduced when MPDA is added dose-wise to phosphoric acid at a reaction temperature of 220oC. The reaction mechanism of the hydrolysis reaction was investigated by isotopic lable incorporation, followed by analysis by NMR. This was done by hydrolysing MPDA using deuterated phosphoric acid (D3PO4). D3PO4 was generated by dissolving phosphorus pentoxide in deuterium oxide. The resorcinol product obtained from the hydrolysis using D3PO4 was found to be deuterated on the C-2, C-4 and C-6 positions. This suggests that the hydrolysis reaction involves protonation of MPDA on these positions, and this results in the formation of an iminium ion as one of the resonance forms. Hydrolysis then occurs on the positively charged carbon of this species. Fertiliser grade phosphoric acid can be used in the hydrolysis reaction, provided sulphates are removed before the acid is used in the hydrolysis reaction. The hydrolysis reaction using either ammonium sulphate or sulphuric acid produces resorcinol in yields lower than 60% if the hydrolysis is conducted in one pass. If these catalysts are used in the hydrolysis reaction, the reaction mixture needs to be re-heated after removal of resorcinol in order to increase the yield. Hydrolysis of MPDA using zirconium phosphate as catalyst gave resorcinol yields in excess of 90% over 24 hours. These reactions were carried out at very low concentrations of MPDA (0.3%). The mode of catalysis in these reactions is unclear. There is a possibility that the reaction is catalysed by phosphoric acid that leaches out of zirconium phosphate at high temperatures. The reaction might therefore not differ mechanistically from the phosphoric acid catalysed reaction. Further studies are required to clarify this point.
- Full Text:
- Date Issued: 2002
The land question in South Africa, Zimbabwe and Kenya: a geographical perspective on resource endowment
- Fox, Roddy C, Rowntree, Kate M
- Authors: Fox, Roddy C , Rowntree, Kate M
- Date: 2002
- Language: English
- Type: Conference paper
- Identifier: vital:6664 , http://hdl.handle.net/10962/d1006671
- Description: In sharp contrast to the debates concerning land policy, land tenure and sustainable resource management in South Africa is any input concerning the geographical distribution of land productivity. This paper attempts to redress this imbalance by providing an empirical investigation of land potential in South Africa. In this way we intend to provide the crucial context for policy and academic studies of the land issue in South Africa. Furthermore, we will undertake our study in such a way that comparison can be made to Zimbabwe and Kenya where the land issue has been such a critical component of the post-colonial development process. Theoretically our work is contextualised within the debates surrounding the importance of geographical endowments, institutions and policies in the development process.
- Full Text:
- Date Issued: 2002
- Authors: Fox, Roddy C , Rowntree, Kate M
- Date: 2002
- Language: English
- Type: Conference paper
- Identifier: vital:6664 , http://hdl.handle.net/10962/d1006671
- Description: In sharp contrast to the debates concerning land policy, land tenure and sustainable resource management in South Africa is any input concerning the geographical distribution of land productivity. This paper attempts to redress this imbalance by providing an empirical investigation of land potential in South Africa. In this way we intend to provide the crucial context for policy and academic studies of the land issue in South Africa. Furthermore, we will undertake our study in such a way that comparison can be made to Zimbabwe and Kenya where the land issue has been such a critical component of the post-colonial development process. Theoretically our work is contextualised within the debates surrounding the importance of geographical endowments, institutions and policies in the development process.
- Full Text:
- Date Issued: 2002
The legal effect of a coup d'etat on traditional constitutional concepts
- Authors: Mkwentla, Nelson Koala
- Date: 2002
- Subjects: Coups d'état , Constitutional law
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3684 , http://hdl.handle.net/10962/d1003199 , Coups d'état , Constitutional law
- Description: This thesis deals with constitutional law and other legal subjects such as Jurisprudence and Judicial Review. One constitution is distinguishable from another by its own provisions. These provisions are usually referred to as either the basic characteristics or features of the particular constitution and these are invariably derived from the basic political philosophy and constitutional arrangements of the particular country. A coup affects these characteristics in different ways. Some automatically disappear as being incompatible with the revolution; some are modified, others are strengthened. The usurpers may choose to set aside the constitution completely and replace it with another, or amend it to suit the new situation, or rule without any constitution. This often happens amidst the rattle of weapons and the whirr of military engines in and around the capital of a given country on that awesome occasion. This thesis sets out to examine the legal aspects of a coup d’ etat. The thesis is divided into six broad sections. Part one will deal with the theoretical background. I shall discuss an overview of Kelsen’s pure theory of law. The second part deals with the scope of its application in revolutionary situations and will also touch upon the reason behind the Kelsen’s theory as shown by decided cases from country to country. The third part deals with the essence as well as the significance of the doctrine of necessity to validate unconstitutional acts in the case of a coup d’ etat. This discussion is to pave the way for the fourth part which is to explore the position of judges who took oath of office under the old constitution. I am to explain their position after a coup d’ etat. The fifth part forms the gist of my research. I shall examine the effect of a coup d’ etat on traditional constitutional concepts such as fundamental rights, separation of powers, rule of law and judicial review in the military regime. The sixth part will deal with African experience. I shall include recommendations and conclusions drawn from the Lesotho and Uganda experiences.
- Full Text:
- Date Issued: 2002
- Authors: Mkwentla, Nelson Koala
- Date: 2002
- Subjects: Coups d'état , Constitutional law
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3684 , http://hdl.handle.net/10962/d1003199 , Coups d'état , Constitutional law
- Description: This thesis deals with constitutional law and other legal subjects such as Jurisprudence and Judicial Review. One constitution is distinguishable from another by its own provisions. These provisions are usually referred to as either the basic characteristics or features of the particular constitution and these are invariably derived from the basic political philosophy and constitutional arrangements of the particular country. A coup affects these characteristics in different ways. Some automatically disappear as being incompatible with the revolution; some are modified, others are strengthened. The usurpers may choose to set aside the constitution completely and replace it with another, or amend it to suit the new situation, or rule without any constitution. This often happens amidst the rattle of weapons and the whirr of military engines in and around the capital of a given country on that awesome occasion. This thesis sets out to examine the legal aspects of a coup d’ etat. The thesis is divided into six broad sections. Part one will deal with the theoretical background. I shall discuss an overview of Kelsen’s pure theory of law. The second part deals with the scope of its application in revolutionary situations and will also touch upon the reason behind the Kelsen’s theory as shown by decided cases from country to country. The third part deals with the essence as well as the significance of the doctrine of necessity to validate unconstitutional acts in the case of a coup d’ etat. This discussion is to pave the way for the fourth part which is to explore the position of judges who took oath of office under the old constitution. I am to explain their position after a coup d’ etat. The fifth part forms the gist of my research. I shall examine the effect of a coup d’ etat on traditional constitutional concepts such as fundamental rights, separation of powers, rule of law and judicial review in the military regime. The sixth part will deal with African experience. I shall include recommendations and conclusions drawn from the Lesotho and Uganda experiences.
- Full Text:
- Date Issued: 2002
The life history of selected coastal foredune species of South Africa
- Authors: Knevel, Irma Cornelia
- Date: 2002
- Subjects: Sand dune plants -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4207 , http://hdl.handle.net/10962/d1003776
- Description: South African dune fields are severely threatened by human expansion and in the long run the stabilisation of many dunes will be necessary. The alien grass Ammophila arenaria is the most important drift sand stabiliser at present in South Africa. Although not invasive, the current impact of A. arenaria on the dune systems of South Africa is considerable, and thus the stabilising benefit of the grass seemed to may be outweighed by its negative consequences. It is therefore preferable to use indigenous sand stabilising species. In order to define guidelines for the application of indigenous plants for stabilisation, their autecology should be studied first to enhance the chance of successful stabilisation results. The main aim of the present thesis was to gather information on the life history processes of selected indigenous, sand stabilising foredune species. To investigate the growth of foredune pioneer species, the common pioneer Scaevola plumieri was followed over a three-year period to determine the growth season and leaf phenology. Soil-borne pathogens are known to influence the growth and vegetation dynamics of foredune species. To examine this effect on the South African foredunes the rhizosphere soil and the roots of several species were studied. To test the effect of the nematode fauna on succeeding plant species a transplantation experiment was carried out. The seed stage is the only life-cycle stage that can survive unfavourable conditions. Therefore, the seed ecology of several foredune species was studied extensively to determine the reproductive season, the seed production, the fate of seeds after shedding (germination, seawater dispersal), germination requirements and seed bank strategy. Seeds of the species Arctotheca populifolia, Ipomoea pes-caprae, Myrica cordifolia, and Scaevola plumieri were subjected to germination trials, field observations on seedling survival, and scarification and stratification experiments. This was done to obtain information about the germination requirements and to determine the reproductive season and growth season. The seed bank strategy of the foredune species, as well as the seed bank density, was determined by extensive sampling along the Cape coast. The species S. plumieri thrived under sand accretion situations, which makes it a good candidate for stabilisation purposes. The growth of S. plumieri was seasonal, with the highest leaf production during spring and summer. The stem position on the foredune had a strong effect on the overall performance of S. plumieri , with the stems situated on the landward face of the foredune showing higher leaf and seed production. Theiii nematode survey of soil and roots of several foredune species showed that all plant species featured a specific nematode fauna in the rhizosphere soil and the roots. The specific nematode fauna affected the growth of foreign plant species in the transplantation experiment, resulting in a lower root and/or shoot biomass production. Most of the foredune species produce seeds from spring to late summer. For S. plumieri the position of the stem on the dunes, as well as the predation of unripe seeds affected the number of seeds produced. The highest production was found for the landward faced stems. The S. plumieri seeds were able to float on seawater for at least three months without losing viability, as was observed for seeds of I. pes-caprae. The seeds of M. cordifolia, however, sank after a few days, but their viability was not affected. The rhizome fragments of A. arenaria and S. virginicus floated for 120 days, whereas the fragments of E. villosa sunk after one day. The viability of S. virginicus fragments was affected by the duration in seawater by an increase in sprouting time. The seeds of all species tested germinated readily under controlled conditions, except S. plumieri seeds which required a long lag-phase before germination. In the field the seeds of A. populifolia, I. pes-caprae and S. plumieri germinated, producing many seedlings. Only the seedlings of A. populifolia and S. plumieri survived. Of the species found in the foredunes 57% was represented in the soil seed bank. For most species, the seeds that were found in the seed bank showed viability of at least 40%. Many of the seeds found were older than one year, suggesting a short-term persistent seed bank. The present study is a start in filling the gap in information on dune pioneer and foredune species. The conclusion was that in general all species in the present study were easy to grow under controlled conditions, and thus could be used for stabilisation purposes. When the more rapidly growing pioneer species are planted in combination with succeeding foredune species, a functional and aesthetic ecosystem could be created.
- Full Text:
- Date Issued: 2002
- Authors: Knevel, Irma Cornelia
- Date: 2002
- Subjects: Sand dune plants -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4207 , http://hdl.handle.net/10962/d1003776
- Description: South African dune fields are severely threatened by human expansion and in the long run the stabilisation of many dunes will be necessary. The alien grass Ammophila arenaria is the most important drift sand stabiliser at present in South Africa. Although not invasive, the current impact of A. arenaria on the dune systems of South Africa is considerable, and thus the stabilising benefit of the grass seemed to may be outweighed by its negative consequences. It is therefore preferable to use indigenous sand stabilising species. In order to define guidelines for the application of indigenous plants for stabilisation, their autecology should be studied first to enhance the chance of successful stabilisation results. The main aim of the present thesis was to gather information on the life history processes of selected indigenous, sand stabilising foredune species. To investigate the growth of foredune pioneer species, the common pioneer Scaevola plumieri was followed over a three-year period to determine the growth season and leaf phenology. Soil-borne pathogens are known to influence the growth and vegetation dynamics of foredune species. To examine this effect on the South African foredunes the rhizosphere soil and the roots of several species were studied. To test the effect of the nematode fauna on succeeding plant species a transplantation experiment was carried out. The seed stage is the only life-cycle stage that can survive unfavourable conditions. Therefore, the seed ecology of several foredune species was studied extensively to determine the reproductive season, the seed production, the fate of seeds after shedding (germination, seawater dispersal), germination requirements and seed bank strategy. Seeds of the species Arctotheca populifolia, Ipomoea pes-caprae, Myrica cordifolia, and Scaevola plumieri were subjected to germination trials, field observations on seedling survival, and scarification and stratification experiments. This was done to obtain information about the germination requirements and to determine the reproductive season and growth season. The seed bank strategy of the foredune species, as well as the seed bank density, was determined by extensive sampling along the Cape coast. The species S. plumieri thrived under sand accretion situations, which makes it a good candidate for stabilisation purposes. The growth of S. plumieri was seasonal, with the highest leaf production during spring and summer. The stem position on the foredune had a strong effect on the overall performance of S. plumieri , with the stems situated on the landward face of the foredune showing higher leaf and seed production. Theiii nematode survey of soil and roots of several foredune species showed that all plant species featured a specific nematode fauna in the rhizosphere soil and the roots. The specific nematode fauna affected the growth of foreign plant species in the transplantation experiment, resulting in a lower root and/or shoot biomass production. Most of the foredune species produce seeds from spring to late summer. For S. plumieri the position of the stem on the dunes, as well as the predation of unripe seeds affected the number of seeds produced. The highest production was found for the landward faced stems. The S. plumieri seeds were able to float on seawater for at least three months without losing viability, as was observed for seeds of I. pes-caprae. The seeds of M. cordifolia, however, sank after a few days, but their viability was not affected. The rhizome fragments of A. arenaria and S. virginicus floated for 120 days, whereas the fragments of E. villosa sunk after one day. The viability of S. virginicus fragments was affected by the duration in seawater by an increase in sprouting time. The seeds of all species tested germinated readily under controlled conditions, except S. plumieri seeds which required a long lag-phase before germination. In the field the seeds of A. populifolia, I. pes-caprae and S. plumieri germinated, producing many seedlings. Only the seedlings of A. populifolia and S. plumieri survived. Of the species found in the foredunes 57% was represented in the soil seed bank. For most species, the seeds that were found in the seed bank showed viability of at least 40%. Many of the seeds found were older than one year, suggesting a short-term persistent seed bank. The present study is a start in filling the gap in information on dune pioneer and foredune species. The conclusion was that in general all species in the present study were easy to grow under controlled conditions, and thus could be used for stabilisation purposes. When the more rapidly growing pioneer species are planted in combination with succeeding foredune species, a functional and aesthetic ecosystem could be created.
- Full Text:
- Date Issued: 2002
The medicinal chemistry of the isomers of the cyclic dipeptide: cyclo(Trp-Pro)
- Authors: Jamie, Hajierah
- Date: 2002
- Subjects: Pharmaceutical chemistry , Cyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
- Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
- Full Text:
- Date Issued: 2002
- Authors: Jamie, Hajierah
- Date: 2002
- Subjects: Pharmaceutical chemistry , Cyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
- Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
- Full Text:
- Date Issued: 2002
The molecular microbial ecology of sulfate reduction in the Rhodes BioSURE process
- Authors: Chauke, Chesa Gift
- Date: 2002
- Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
- Full Text:
- Date Issued: 2002
- Authors: Chauke, Chesa Gift
- Date: 2002
- Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
- Full Text:
- Date Issued: 2002
The new moral order and racism in South Africa post 11 September 2001
- Painter, D, Macleod, Catriona I
- Authors: Painter, D , Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6215 , http://hdl.handle.net/10962/d1006266
- Description: In this paper we argue that globalisation imposes on ‘developing’ countries more than an economic order; they find themselves with the moral imperative to align themselves with the West against its Others, increasingly portrayed as Islamic fundamentalists. The 11 September terror attacks in the United States of America have pushed this process to a new level, with the attacks represented as no less than a barbaric attack on ‘civilisation’. Through an analysis of a newspaper article reporting on the disciplining of a Muslim woman in for wearing an Osama Bin Laden t-shirt to work in South Africa, we indicate how this moral representation of the 11 September events and the Islamic Other have unique local effects. In South Africa it creates yet more possibilities for racialising practices to continue without being framed in explicitly racial terms. We further reflect on the implications of these events, and the complex interplay of the global and the local they demonstrate, for critical psychology in South Africa.
- Full Text:
- Date Issued: 2002
- Authors: Painter, D , Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6215 , http://hdl.handle.net/10962/d1006266
- Description: In this paper we argue that globalisation imposes on ‘developing’ countries more than an economic order; they find themselves with the moral imperative to align themselves with the West against its Others, increasingly portrayed as Islamic fundamentalists. The 11 September terror attacks in the United States of America have pushed this process to a new level, with the attacks represented as no less than a barbaric attack on ‘civilisation’. Through an analysis of a newspaper article reporting on the disciplining of a Muslim woman in for wearing an Osama Bin Laden t-shirt to work in South Africa, we indicate how this moral representation of the 11 September events and the Islamic Other have unique local effects. In South Africa it creates yet more possibilities for racialising practices to continue without being framed in explicitly racial terms. We further reflect on the implications of these events, and the complex interplay of the global and the local they demonstrate, for critical psychology in South Africa.
- Full Text:
- Date Issued: 2002
The political ecology of wildlife conservation in Kenya, 1895-1975
- Authors: Matheka, Reuben M
- Date: 2002
- Subjects: Wildlife conservation -- Kenya Environmental policy -- Kenya Wildlife conservation -- Political aspects -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2595 , http://hdl.handle.net/10962/d1007530
- Description: The study examines the development of wildlife conservation policy and practice in Kenya from 1895 to 1975. Started by the colonial state as part of its resource control programme, wildlife conservation in Kenya gradually became an important aspect of the country's economy chiefly because of its significance as the basis of a vibrant tourist industry. The conservation programme was also important to conservationists who viewed Kenya's wildlife as a heritage to humanity. Similarly, local communities, which were affected in various ways by wildlife conservation policies, had their own perceptions of the programme. All this led to the proliferation of groups whose interests were potentially conflicting. Wildlife conservation in Kenya during the period under examination was thus characterised by various struggles between interest groups such as conservationists, the state, and local communities. The struggles centred around such issues as the costs and benefits of conservation and were manifested through anti-conservation activities like the poaching of wild animals by dissatisfied groups. These struggles changed over time in line with social, economic, political, and ecological developments. International events/processes (such as the two world wars, economic booms/depressions, and decolonisation) triggered local processes which influenced conservationism either positively or negatively. Wildlife conservation in Kenya during the period under study was dynamic. The thesis challenges the myth of a monolithic 'colonial' wildlife policy often implied in many studies on the subject. The thesis also lays emphasis on the ecological basis of wildlife conservation while recognising the impact of social, political, and economic developments on the evolution of wildlife conservation policy and practice in Kenya. The country's 'geography' not only provided the foundation for conservation but also influenced the programme over time. Droughts, floods, army worm infestations, and other 'natural' occurrences interacted with social and economic changes, such as population growth and the development of capitalism, to shape conservation policy. The conservation programme was thus influenced by a complex interaction of a variety of factors.
- Full Text:
- Date Issued: 2002
- Authors: Matheka, Reuben M
- Date: 2002
- Subjects: Wildlife conservation -- Kenya Environmental policy -- Kenya Wildlife conservation -- Political aspects -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2595 , http://hdl.handle.net/10962/d1007530
- Description: The study examines the development of wildlife conservation policy and practice in Kenya from 1895 to 1975. Started by the colonial state as part of its resource control programme, wildlife conservation in Kenya gradually became an important aspect of the country's economy chiefly because of its significance as the basis of a vibrant tourist industry. The conservation programme was also important to conservationists who viewed Kenya's wildlife as a heritage to humanity. Similarly, local communities, which were affected in various ways by wildlife conservation policies, had their own perceptions of the programme. All this led to the proliferation of groups whose interests were potentially conflicting. Wildlife conservation in Kenya during the period under examination was thus characterised by various struggles between interest groups such as conservationists, the state, and local communities. The struggles centred around such issues as the costs and benefits of conservation and were manifested through anti-conservation activities like the poaching of wild animals by dissatisfied groups. These struggles changed over time in line with social, economic, political, and ecological developments. International events/processes (such as the two world wars, economic booms/depressions, and decolonisation) triggered local processes which influenced conservationism either positively or negatively. Wildlife conservation in Kenya during the period under study was dynamic. The thesis challenges the myth of a monolithic 'colonial' wildlife policy often implied in many studies on the subject. The thesis also lays emphasis on the ecological basis of wildlife conservation while recognising the impact of social, political, and economic developments on the evolution of wildlife conservation policy and practice in Kenya. The country's 'geography' not only provided the foundation for conservation but also influenced the programme over time. Droughts, floods, army worm infestations, and other 'natural' occurrences interacted with social and economic changes, such as population growth and the development of capitalism, to shape conservation policy. The conservation programme was thus influenced by a complex interaction of a variety of factors.
- Full Text:
- Date Issued: 2002
The pursuit of paternal custody
- Authors: Pieterse, Johanna Tyziena
- Date: 2002
- Subjects: Custody of children -- South Africa , Paternal custody -- South Africa , Divorced fathers -- South Africa , Father and child -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3398 , http://hdl.handle.net/10962/d1018266
- Description: Issues concerning children may be the most intense and emotive areas of divorce and can lead to spectacular legal battles. Social work practice revealed that it is often the father who leaves the court, stripped of his fatherhood by a court order that only grants him limited access to his own children. Some divorced fathers disengage from their children's lives but there is documented evidence of South African fathers who desire continuity in their relationships with their children after divorce. An interest in these fathers prompted this study. Fathers who challenged maternal custody were selected since it was assumed that their lived experiences would include non-custodial as well as custodial fatherhood. The study was approached from a constructivist position and was further informed by a family systems theory. South African and international literature was perused followed by an exploratory study on the relatively uncharted terrain of paternal custody. A qualitative method was used and one unstructured interview with a schedule was conducted with each of the five respondents who were selected according to non-probability purposive sampling methods. Interviews were recorded and transcribed verbatim. Data was analysed cross-sectionally around certain themes and categories that were extracted from the data. The most significant findings of the study which appear to resemble some earlier national and international findings, are summarised as follows: Some fathers appear to have sound motives for pursuing custody of their children. These fathers, if afforded the opportunity, find fulfilment in parenting their children whom they perceive to be happy and prosperous in their care. There are fathers in whom divorce causes clear and profound signs of distress which appear to be related to the loss of the pre-divorce father I child relationship. The feeling of powerlessness to effect the well-being of their children as they see it was emphasised. Recommendations generated from these findings relate to the elimination of gender bias from custody decisions, including fathers in therapeutic interventions with divorced families and the provision of family courts and mediation services as suggested in the White Paper for Social Welfare. Recommendations for future research are also presented.
- Full Text:
- Date Issued: 2002
- Authors: Pieterse, Johanna Tyziena
- Date: 2002
- Subjects: Custody of children -- South Africa , Paternal custody -- South Africa , Divorced fathers -- South Africa , Father and child -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3398 , http://hdl.handle.net/10962/d1018266
- Description: Issues concerning children may be the most intense and emotive areas of divorce and can lead to spectacular legal battles. Social work practice revealed that it is often the father who leaves the court, stripped of his fatherhood by a court order that only grants him limited access to his own children. Some divorced fathers disengage from their children's lives but there is documented evidence of South African fathers who desire continuity in their relationships with their children after divorce. An interest in these fathers prompted this study. Fathers who challenged maternal custody were selected since it was assumed that their lived experiences would include non-custodial as well as custodial fatherhood. The study was approached from a constructivist position and was further informed by a family systems theory. South African and international literature was perused followed by an exploratory study on the relatively uncharted terrain of paternal custody. A qualitative method was used and one unstructured interview with a schedule was conducted with each of the five respondents who were selected according to non-probability purposive sampling methods. Interviews were recorded and transcribed verbatim. Data was analysed cross-sectionally around certain themes and categories that were extracted from the data. The most significant findings of the study which appear to resemble some earlier national and international findings, are summarised as follows: Some fathers appear to have sound motives for pursuing custody of their children. These fathers, if afforded the opportunity, find fulfilment in parenting their children whom they perceive to be happy and prosperous in their care. There are fathers in whom divorce causes clear and profound signs of distress which appear to be related to the loss of the pre-divorce father I child relationship. The feeling of powerlessness to effect the well-being of their children as they see it was emphasised. Recommendations generated from these findings relate to the elimination of gender bias from custody decisions, including fathers in therapeutic interventions with divorced families and the provision of family courts and mediation services as suggested in the White Paper for Social Welfare. Recommendations for future research are also presented.
- Full Text:
- Date Issued: 2002
The registration of generic topical corticosteroid formulations in South Africa: a report
- Haigh, John M, Smith, Eric W
- Authors: Haigh, John M , Smith, Eric W
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6368 , http://hdl.handle.net/10962/d1006068
- Description: [From the text]Topical corticosteroid formulations are used widely for a variety of skin conditions such as psoriasis and eczema. The most commonly used formulation types are cream, ointment, lotion and scalp application, with some mousse formulations being released recently onto the market for scalp application. The type of formulation used depends on the condition being treated. Dry lesions are normally treated with ointments and wet lesions with creams. Cosmetically, cream formulations are more acceptable as they can be rubbed in, thus leaving no residual oiliness. Scalp applications have to be less viscous to allow the formulation to pass through the hair and contact the scalp. Occlusion with plastic wrapping hydrates the stratum corneum and facilitates the passage of the corticosteroid through this barrier to the basal layer where the therapeutic effect is required.
- Full Text:
- Date Issued: 2002
- Authors: Haigh, John M , Smith, Eric W
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6368 , http://hdl.handle.net/10962/d1006068
- Description: [From the text]Topical corticosteroid formulations are used widely for a variety of skin conditions such as psoriasis and eczema. The most commonly used formulation types are cream, ointment, lotion and scalp application, with some mousse formulations being released recently onto the market for scalp application. The type of formulation used depends on the condition being treated. Dry lesions are normally treated with ointments and wet lesions with creams. Cosmetically, cream formulations are more acceptable as they can be rubbed in, thus leaving no residual oiliness. Scalp applications have to be less viscous to allow the formulation to pass through the hair and contact the scalp. Occlusion with plastic wrapping hydrates the stratum corneum and facilitates the passage of the corticosteroid through this barrier to the basal layer where the therapeutic effect is required.
- Full Text:
- Date Issued: 2002
The relationship between the leadership, internal quality, and customer satisfaction levels of dealerships in a South African motor vehicle organisation
- Authors: Botha, Jennifer
- Date: 2002
- Subjects: Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1185 , http://hdl.handle.net/10962/d1002802 , Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Description: This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected.
- Full Text:
- Date Issued: 2002
- Authors: Botha, Jennifer
- Date: 2002
- Subjects: Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1185 , http://hdl.handle.net/10962/d1002802 , Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Description: This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected.
- Full Text:
- Date Issued: 2002
The relationship between three anxiety related clusters in projective drawings and anxiety and ego-strength scales of the Minnesota multiphasic personality inventory-2
- Authors: Brink, André
- Date: 2002
- Subjects: Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2942 , http://hdl.handle.net/10962/d1002451 , Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Description: Based on the shortcomings of past research, the need for understanding and investigation of the general relationship between self-report measures and human figure drawings required understanding and investigation (Riethmiller & Handler, 1997b; Waehler, 1997) while utilising a quantitative, configural scoring approach. Riethmiller and Handler (1997a; 1997b) hypothesised that subjects have one of two typical approach styles to anxiety/stress that influences their execution of the Human Figure Drawing (HFD) Test: “Avoidance” or “Coping” as measured by composite scoring index clusters. They argue that these two approach styles had to be taken into account when investigating anxiety on the HFD Test. According to Handler and Reyher (1965) those who experience more intense anxiety typically rely on an “Avoidant” approach, while those with lower anxiety typically rely on a “Coping” approach. The “Coping” response is hypothesised to suggest good ego-strength, and the “Avoidant” response poor ego-strength. Handler and Reyher (1964; 1965; 1966) also argued that there are two sources of anxiety on projective drawings: internal and external sources of anxiety. They hypothesised that the “External” anxiety cluster (measured by utilising the car drawing) and self-report measures both assess ‘external’ anxiety. Using Handler’s (1967) HFD index scoring manual, this research therefore inve stigated the level of correlation of the two MMPI-2 anxiety scale scores with (a) the hypothesised Stress Approach HFD cluster scores, as well as with (b) the “External” anxiety cluster score, while the hypothesised Stress Approach HFD cluster scores were compared with the (c) MMPI-2 ego strength scale score. The results of the investigated relationships yielded non-significant correlations overall. The differences in nature of the two measurement instruments, and the potential weaknesses of this study, as two likely explanations for these correlations, are discussed. In the consideration of the differences of the two measurement instruments, the weaknesses of SR measures and criterion-related validity are discussed while self- attributed and implicit motives are contrasted with each other. Potential extraneous variables and possible truncated range are discussed as potential weaknesses of this study.
- Full Text:
- Date Issued: 2002
- Authors: Brink, André
- Date: 2002
- Subjects: Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2942 , http://hdl.handle.net/10962/d1002451 , Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
- Description: Based on the shortcomings of past research, the need for understanding and investigation of the general relationship between self-report measures and human figure drawings required understanding and investigation (Riethmiller & Handler, 1997b; Waehler, 1997) while utilising a quantitative, configural scoring approach. Riethmiller and Handler (1997a; 1997b) hypothesised that subjects have one of two typical approach styles to anxiety/stress that influences their execution of the Human Figure Drawing (HFD) Test: “Avoidance” or “Coping” as measured by composite scoring index clusters. They argue that these two approach styles had to be taken into account when investigating anxiety on the HFD Test. According to Handler and Reyher (1965) those who experience more intense anxiety typically rely on an “Avoidant” approach, while those with lower anxiety typically rely on a “Coping” approach. The “Coping” response is hypothesised to suggest good ego-strength, and the “Avoidant” response poor ego-strength. Handler and Reyher (1964; 1965; 1966) also argued that there are two sources of anxiety on projective drawings: internal and external sources of anxiety. They hypothesised that the “External” anxiety cluster (measured by utilising the car drawing) and self-report measures both assess ‘external’ anxiety. Using Handler’s (1967) HFD index scoring manual, this research therefore inve stigated the level of correlation of the two MMPI-2 anxiety scale scores with (a) the hypothesised Stress Approach HFD cluster scores, as well as with (b) the “External” anxiety cluster score, while the hypothesised Stress Approach HFD cluster scores were compared with the (c) MMPI-2 ego strength scale score. The results of the investigated relationships yielded non-significant correlations overall. The differences in nature of the two measurement instruments, and the potential weaknesses of this study, as two likely explanations for these correlations, are discussed. In the consideration of the differences of the two measurement instruments, the weaknesses of SR measures and criterion-related validity are discussed while self- attributed and implicit motives are contrasted with each other. Potential extraneous variables and possible truncated range are discussed as potential weaknesses of this study.
- Full Text:
- Date Issued: 2002
The remote configuration of devices within home entertainment networks
- Authors: Dembovsky, Colin
- Date: 2002
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4685 , http://hdl.handle.net/10962/d1007795 , Home entertainment systems , Home video systems
- Description: This thesis examines home entertainment network remote configuration solutions. It does so by inspecting four home entertainment networking solution specifications - HAVi, Jini, AV/C and UPnP. Two of these (AV/C and UPnP) are implemented partially for a system allowing a TV to configure an AudioNideo Receiver (AV/R) remotely on the network (a process known as remote configuration). The two implementations are then more closely investigated and several implementation differences in the approach between the remote configuration method of device configuration and other methods of device configuration are discerned. These different approaches are then categorised into one of two theoretical models of communication for configuring devices on home entertainment networks - the Rendering model and the Programmed model. By classifying a particular method of device configuration into one of the two models, manufacturers can quickly determine the inherent strengths and weaknesses of that method , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Dembovsky, Colin
- Date: 2002
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4685 , http://hdl.handle.net/10962/d1007795 , Home entertainment systems , Home video systems
- Description: This thesis examines home entertainment network remote configuration solutions. It does so by inspecting four home entertainment networking solution specifications - HAVi, Jini, AV/C and UPnP. Two of these (AV/C and UPnP) are implemented partially for a system allowing a TV to configure an AudioNideo Receiver (AV/R) remotely on the network (a process known as remote configuration). The two implementations are then more closely investigated and several implementation differences in the approach between the remote configuration method of device configuration and other methods of device configuration are discerned. These different approaches are then categorised into one of two theoretical models of communication for configuring devices on home entertainment networks - the Rendering model and the Programmed model. By classifying a particular method of device configuration into one of the two models, manufacturers can quickly determine the inherent strengths and weaknesses of that method , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text: