Particle precipitation effects on the South African ionosphere
- Authors: Sibanda, Patrick
- Date: 2007
- Subjects: Ionosphere -- South Africa , Precipitation (Chemistry) -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5481 , http://hdl.handle.net/10962/d1005267 , Ionosphere -- South Africa , Precipitation (Chemistry) -- South Africa
- Description: Particle precipitation involves the injection of energetic particles into the ionosphere which could increase the ionisation and conductivity of the upper atmosphere. The goal of this study was to examine the ionospheric response and changes due to particle precipitation in the region over South Africa, using a combination of groundbased and satellite instruments. Particle precipitation events were identified from satellite particle flux measurements of the Defence Meteorological Satellite Program (DMSP). Comprehensive studies were done on the events of 5 April, 2000 and 7 October, 2000. Analysis of the data from the satellite instruments indicates that no particle precipitation was observed over the South African region during these events and that it is unlikely to occur during other such events. To validate the data, methods and tools used in this study, precipitation in the South Atlantic anomaly (SAA) region is used. Satellite ion density measurements revealed that strong density enhancements occurred over the SAA region at satellite altitudes during the precipitation events, but this did not occur in the South African region. The measurements also revealed how the ionisation enhancements in the SAA region correlated with geomagnetic and solar activities. Particle precipitation and convective electric fields are two major magnetospheric energy sources to the upper atmosphere in the auroral and the SAA regions. These increase dramatically during geomagnetic storms and can disturb thermospheric circulation in the atmosphere and alter the rates of production and recombination of the ionised species. Ionosonde observations at Grahamstown, South Africa (33.30S, 26.50E), provided the data to build a picture of the response of the ionosphere over the South African region to particle precipitation during the precipitation events. This analysis showed that, within the confines of the available data, no direct connections between particle precipitation events and disturbances in the ionosphere over this region were revealed.
- Full Text:
- Date Issued: 2007
- Authors: Sibanda, Patrick
- Date: 2007
- Subjects: Ionosphere -- South Africa , Precipitation (Chemistry) -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5481 , http://hdl.handle.net/10962/d1005267 , Ionosphere -- South Africa , Precipitation (Chemistry) -- South Africa
- Description: Particle precipitation involves the injection of energetic particles into the ionosphere which could increase the ionisation and conductivity of the upper atmosphere. The goal of this study was to examine the ionospheric response and changes due to particle precipitation in the region over South Africa, using a combination of groundbased and satellite instruments. Particle precipitation events were identified from satellite particle flux measurements of the Defence Meteorological Satellite Program (DMSP). Comprehensive studies were done on the events of 5 April, 2000 and 7 October, 2000. Analysis of the data from the satellite instruments indicates that no particle precipitation was observed over the South African region during these events and that it is unlikely to occur during other such events. To validate the data, methods and tools used in this study, precipitation in the South Atlantic anomaly (SAA) region is used. Satellite ion density measurements revealed that strong density enhancements occurred over the SAA region at satellite altitudes during the precipitation events, but this did not occur in the South African region. The measurements also revealed how the ionisation enhancements in the SAA region correlated with geomagnetic and solar activities. Particle precipitation and convective electric fields are two major magnetospheric energy sources to the upper atmosphere in the auroral and the SAA regions. These increase dramatically during geomagnetic storms and can disturb thermospheric circulation in the atmosphere and alter the rates of production and recombination of the ionised species. Ionosonde observations at Grahamstown, South Africa (33.30S, 26.50E), provided the data to build a picture of the response of the ionosphere over the South African region to particle precipitation during the precipitation events. This analysis showed that, within the confines of the available data, no direct connections between particle precipitation events and disturbances in the ionosphere over this region were revealed.
- Full Text:
- Date Issued: 2007
Passing the spear : a grounded theory study of the influence of family business value sets on succession planning in black family-owned businesses
- Authors: Musengi, Sandra
- Date: 2007
- Subjects: Grounded theory Family-owned business enterprises Family-owned business enterprises -- Succession Family-owned business enterprises -- Management Business enterprises, Black Business planning
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1192 , http://hdl.handle.net/10962/d1007056
- Description: Literature suggests that a small number of family businesses are able to make the transition from the founder to other family members with a common reason cited being the lack of planning. This study aims to build understanding of leadership succession in family businesses by focusing on the influence of a founder's family business value set on the succession planning process in Black family-owned businesses. Using the Strauss and Corbin (1990) grounded theory method, this study develops a theory of succession planning of Black familyowned businesses labelled Passing the Spear which is comprised of three stages based on an analysis of 21 qualitative interviews. The Spear was an analogy used to represent both the values of the founder and the family business, thus in Passing the Spear, founders where essentially performing a dual transfer of their values and leadership to the successor. The implementation of the process Passing the Spear was influenced by the family business value set of the founder, which in this study, were labelled as Traditional, Progressive, and Transitional. These value sets were distinguished by their behaviour regarding their choice of successor where founders with a traditional value set exhibited gatekeeping behaviour, while the behaviour of founders with a progressive value set was labelled navigating, and finally, founders with a transitional value set demonstrated behaviour labelled exploring. Furthermore, it was found that after the successor had been chosen, founders appeared to follow a generic succession planning process, however, the ease and timing of implementation was influenced by the family business context, evidence of being proactive and the degree of family business resilience. The process of Passing the Spear comprised of three stages of (a) Showing the spear where the founder's focus is on the induction and socialization of the successor using the strategies of bringing the successor into the family business and managing the family-business interface using relationships; (b) Explaining the spear entailed founders using the strategies of sharing knowledge and teaching the successors about the family business; and ( c) Sharing the spear was where founders focused on empowering the successors by implementing strategies of sharing responsibilities and learning from the successor.The process provides insights into the influence of family business values on the succession planning process and can be useful for founders of Black family-owned businesses in planning for succession in their businesses. In addition, the study provides another perspective of succession planning and offers a contribution to the literature for understanding succession in Black family-owned businesses.
- Full Text:
- Date Issued: 2007
- Authors: Musengi, Sandra
- Date: 2007
- Subjects: Grounded theory Family-owned business enterprises Family-owned business enterprises -- Succession Family-owned business enterprises -- Management Business enterprises, Black Business planning
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1192 , http://hdl.handle.net/10962/d1007056
- Description: Literature suggests that a small number of family businesses are able to make the transition from the founder to other family members with a common reason cited being the lack of planning. This study aims to build understanding of leadership succession in family businesses by focusing on the influence of a founder's family business value set on the succession planning process in Black family-owned businesses. Using the Strauss and Corbin (1990) grounded theory method, this study develops a theory of succession planning of Black familyowned businesses labelled Passing the Spear which is comprised of three stages based on an analysis of 21 qualitative interviews. The Spear was an analogy used to represent both the values of the founder and the family business, thus in Passing the Spear, founders where essentially performing a dual transfer of their values and leadership to the successor. The implementation of the process Passing the Spear was influenced by the family business value set of the founder, which in this study, were labelled as Traditional, Progressive, and Transitional. These value sets were distinguished by their behaviour regarding their choice of successor where founders with a traditional value set exhibited gatekeeping behaviour, while the behaviour of founders with a progressive value set was labelled navigating, and finally, founders with a transitional value set demonstrated behaviour labelled exploring. Furthermore, it was found that after the successor had been chosen, founders appeared to follow a generic succession planning process, however, the ease and timing of implementation was influenced by the family business context, evidence of being proactive and the degree of family business resilience. The process of Passing the Spear comprised of three stages of (a) Showing the spear where the founder's focus is on the induction and socialization of the successor using the strategies of bringing the successor into the family business and managing the family-business interface using relationships; (b) Explaining the spear entailed founders using the strategies of sharing knowledge and teaching the successors about the family business; and ( c) Sharing the spear was where founders focused on empowering the successors by implementing strategies of sharing responsibilities and learning from the successor.The process provides insights into the influence of family business values on the succession planning process and can be useful for founders of Black family-owned businesses in planning for succession in their businesses. In addition, the study provides another perspective of succession planning and offers a contribution to the literature for understanding succession in Black family-owned businesses.
- Full Text:
- Date Issued: 2007
Past trauma, anxious future a case-based evaluation of the Ehlers and Clark model for PTSD applied in Africa
- Authors: Van der Linde, Francois
- Date: 2007
- Subjects: Cognitive therapy Post-traumatic stress disorder -- Africa Rape trauma syndrome -- Treatment -- Africa Rape victims -- Africa Anxiety -- Treatment Depression, Mental -- Treatment Post-traumatic stress disorder -- Patients Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3075 , http://hdl.handle.net/10962/d1002584
- Description: This research report documents the therapeutic intervention undertaken with a 23-year-old Swazi rape victim. The format of this research report takes the form of a case study that follows the principles proposed by Fishman (2005). Its aim is to document the treatment process of an individual of African decent in order to establish whether the treatment model can be effective in clinical settings and in contexts and cultural settings different from that in which it was developed. The Ehlers and Clark (2000) cognitive therapy model for post-traumatic stress disorder (PTSD) was utilised to assess, conceptualise, and treat the case. The client entered therapy three years after being raped for a third time. The case formulation identified factors maintaining the disorder as well as how other traumatic and abusive events earlier in her life influenced her response to the rapes. Data consisted off audio-tape recordings and detailed written synopses of each assessment and therapy session, psychometric measurement instruments and self-report scales completed throughout the intervention, material written by the client, and a research interview conducted by an independent party. She was treated for PTSD and comorbid depression over a period of five months in accordance with the principles described by Ehlers and Clark and a narrative of the treatment process was written. The case narrative in conjunction with quantitative data suggested that this model assisted the client in initiating a healing process. As such the model was found to be both effective and transportable to an African context. Various points of discussion are highlighted, including the challenges of working with PTSD and comorbid major depression, the client-therapist relationship, and that a client and therapist from different cultures, backgrounds, and with different home languages can work together effectively using the Ehlers and Clark model.
- Full Text:
- Date Issued: 2007
- Authors: Van der Linde, Francois
- Date: 2007
- Subjects: Cognitive therapy Post-traumatic stress disorder -- Africa Rape trauma syndrome -- Treatment -- Africa Rape victims -- Africa Anxiety -- Treatment Depression, Mental -- Treatment Post-traumatic stress disorder -- Patients Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3075 , http://hdl.handle.net/10962/d1002584
- Description: This research report documents the therapeutic intervention undertaken with a 23-year-old Swazi rape victim. The format of this research report takes the form of a case study that follows the principles proposed by Fishman (2005). Its aim is to document the treatment process of an individual of African decent in order to establish whether the treatment model can be effective in clinical settings and in contexts and cultural settings different from that in which it was developed. The Ehlers and Clark (2000) cognitive therapy model for post-traumatic stress disorder (PTSD) was utilised to assess, conceptualise, and treat the case. The client entered therapy three years after being raped for a third time. The case formulation identified factors maintaining the disorder as well as how other traumatic and abusive events earlier in her life influenced her response to the rapes. Data consisted off audio-tape recordings and detailed written synopses of each assessment and therapy session, psychometric measurement instruments and self-report scales completed throughout the intervention, material written by the client, and a research interview conducted by an independent party. She was treated for PTSD and comorbid depression over a period of five months in accordance with the principles described by Ehlers and Clark and a narrative of the treatment process was written. The case narrative in conjunction with quantitative data suggested that this model assisted the client in initiating a healing process. As such the model was found to be both effective and transportable to an African context. Various points of discussion are highlighted, including the challenges of working with PTSD and comorbid major depression, the client-therapist relationship, and that a client and therapist from different cultures, backgrounds, and with different home languages can work together effectively using the Ehlers and Clark model.
- Full Text:
- Date Issued: 2007
Pharmaceutical analysis and quality of complementary medicines : sceletium and associated products
- Patnala, Satya Siva Rama Ranganath Srinivas
- Authors: Patnala, Satya Siva Rama Ranganath Srinivas
- Date: 2007
- Subjects: Alternative medicine , Herbs -- Therapeutic use
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3872 , http://hdl.handle.net/10962/d1018263
- Description: There has been an upsurge in the use of Complementary and Alternate Medicines (CAMs) in both developed and developing countries. Although herbal medicines have been in use for many centuries, their quality, safety and efficacy are still of major concern. Many countries are in the process of integrating CAMs into conventional health care systems based on the knowledge and use of traditional medicines. The quality control (QC) of herbal products usually presents a formidable analytical challenge in view of the complexity of the constituents in plant material and the commercial non-availability of appropriate qualified reference standards. Sceletium, a genus belonging to the family Aizoaceae, has been reported to contain psychoactive alkaloids, specifically mesembrine, mesembrenone, mesembrenol and some other related alkaloids. Sceletium is marketed as dried plant powder and as phyto-pharmaceutical dosage forms. Sceletium products and plant material marketed through health shops and on the internet are associated with unjustified claims of specific therapeutic efficacy and may be of dubious quality. Validated analytical methods to estimate Sceletium alkaloids have not previously been reported in the scientific literature and the available methods have focused only on qualitative estimation. Furthermore, since appropriate markers were not commercially available for use as reference standards, a primary objective of this study was to isolate relevant compounds, qualify them as reference standards which could be applied to develop appropriate validated qualitative and quantitative analytical methods for fingerprinting and assay of Sceletium plant material and dosage forms. The alkaloidal markers mesembrine, mesembrenone and ∆⁷ mesembrenone were isolated by solvent extraction and chromatography from dried plant material. Mesembranol and epimesembranol were synthesised by hydrogenation of the isolated mesembrine using the catalyst platinum (IV) oxide and then further purified by semi-preparative column chromatography. All compounds were subjected to analysis by ¹H, ¹³C, 2-D nuclear magnetic resonance and liquid chromatography-tandem mass spectroscopy. Mesembrine was converted to hydrochloride crystals and mesembranol was isolated as crystals from the hydrogenation reaction mass. These compounds were analysed and characterised by X-ray crystallography. A relatively simple HPLC method for the separation and quantitative analysis of five relevant alkaloidal components in Sceletium was developed and validated. The method was applied to determine the alkaloids in plant material and dosage forms containing Sceletium. An LCMS method developed during the study provided accurate identification of the five relevant Sceletium alkaloids. The method was applied for the quantitative analysis and QC of Sceletium plant material and its dosage forms. This LCMS method was found to efficiently ionize the relevant alkaloidal markers in order to facilitate their detection, identification and quantification in Sceletium plant material as well as for the assay and QC of dosage forms containing Sceletium. The chemotaxonomy of some Sceletium species and commercially available Sceletium dosage forms were successfully studied by the LCMS method. The HPLC and LCMS methods were also used to monitor the bio-conversion of some of the alkaloids while processing the plant material as per traditional method of fermentation. Additionally a high resolution CZE method was developed for the separation of several Sceletium alkaloids in relatively short analysis times. This analytical method was used successfully to fingerprint the alkaloids and quantify mesembrine in Sceletium and its products. Sceletium species grown under varying conditions at different locations, when analyzed, showed major differences in their composition of alkaloids and an enormous difference was found to exist between the various species with respect to the presence and content of alkaloids. Sceletium and its products marketed through health shops and the internet may thus have problems with respect to the quality and related therapeutic efficacy. The QC of Sceletium presents a formidable challenge as Sceletium plants and products contain a complex mixture of compounds. The work presented herein contributes to a growing body of scientific knowledge to improve the QC standards of herbal medicines and also to provide vital information regarding the selection of plant species and information on the specific alkaloidal constituents to the cultivators of Sceletium and the manufacturers of its products.
- Full Text:
- Date Issued: 2007
- Authors: Patnala, Satya Siva Rama Ranganath Srinivas
- Date: 2007
- Subjects: Alternative medicine , Herbs -- Therapeutic use
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3872 , http://hdl.handle.net/10962/d1018263
- Description: There has been an upsurge in the use of Complementary and Alternate Medicines (CAMs) in both developed and developing countries. Although herbal medicines have been in use for many centuries, their quality, safety and efficacy are still of major concern. Many countries are in the process of integrating CAMs into conventional health care systems based on the knowledge and use of traditional medicines. The quality control (QC) of herbal products usually presents a formidable analytical challenge in view of the complexity of the constituents in plant material and the commercial non-availability of appropriate qualified reference standards. Sceletium, a genus belonging to the family Aizoaceae, has been reported to contain psychoactive alkaloids, specifically mesembrine, mesembrenone, mesembrenol and some other related alkaloids. Sceletium is marketed as dried plant powder and as phyto-pharmaceutical dosage forms. Sceletium products and plant material marketed through health shops and on the internet are associated with unjustified claims of specific therapeutic efficacy and may be of dubious quality. Validated analytical methods to estimate Sceletium alkaloids have not previously been reported in the scientific literature and the available methods have focused only on qualitative estimation. Furthermore, since appropriate markers were not commercially available for use as reference standards, a primary objective of this study was to isolate relevant compounds, qualify them as reference standards which could be applied to develop appropriate validated qualitative and quantitative analytical methods for fingerprinting and assay of Sceletium plant material and dosage forms. The alkaloidal markers mesembrine, mesembrenone and ∆⁷ mesembrenone were isolated by solvent extraction and chromatography from dried plant material. Mesembranol and epimesembranol were synthesised by hydrogenation of the isolated mesembrine using the catalyst platinum (IV) oxide and then further purified by semi-preparative column chromatography. All compounds were subjected to analysis by ¹H, ¹³C, 2-D nuclear magnetic resonance and liquid chromatography-tandem mass spectroscopy. Mesembrine was converted to hydrochloride crystals and mesembranol was isolated as crystals from the hydrogenation reaction mass. These compounds were analysed and characterised by X-ray crystallography. A relatively simple HPLC method for the separation and quantitative analysis of five relevant alkaloidal components in Sceletium was developed and validated. The method was applied to determine the alkaloids in plant material and dosage forms containing Sceletium. An LCMS method developed during the study provided accurate identification of the five relevant Sceletium alkaloids. The method was applied for the quantitative analysis and QC of Sceletium plant material and its dosage forms. This LCMS method was found to efficiently ionize the relevant alkaloidal markers in order to facilitate their detection, identification and quantification in Sceletium plant material as well as for the assay and QC of dosage forms containing Sceletium. The chemotaxonomy of some Sceletium species and commercially available Sceletium dosage forms were successfully studied by the LCMS method. The HPLC and LCMS methods were also used to monitor the bio-conversion of some of the alkaloids while processing the plant material as per traditional method of fermentation. Additionally a high resolution CZE method was developed for the separation of several Sceletium alkaloids in relatively short analysis times. This analytical method was used successfully to fingerprint the alkaloids and quantify mesembrine in Sceletium and its products. Sceletium species grown under varying conditions at different locations, when analyzed, showed major differences in their composition of alkaloids and an enormous difference was found to exist between the various species with respect to the presence and content of alkaloids. Sceletium and its products marketed through health shops and the internet may thus have problems with respect to the quality and related therapeutic efficacy. The QC of Sceletium presents a formidable challenge as Sceletium plants and products contain a complex mixture of compounds. The work presented herein contributes to a growing body of scientific knowledge to improve the QC standards of herbal medicines and also to provide vital information regarding the selection of plant species and information on the specific alkaloidal constituents to the cultivators of Sceletium and the manufacturers of its products.
- Full Text:
- Date Issued: 2007
Phthalocyanines : photochemical, electrochemical and biomimetic catalytic behaviour
- Authors: Sehlotho, Nthapo
- Date: 2007
- Subjects: Phthalocyanines Photochemistry Electrochemistry Biomimetics Oxidation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4336 , http://hdl.handle.net/10962/d1004997
- Description: This thesis explored use of metallophthalocyanines as electrocatalysts towards thiol and thiocyanate oxidation, nitrosothiol decomposition and reduction of oxygen, as well as biomimetic and photo-catalysts of cyclohexene oxidation. 2-mercaptoethanol (2-ME), L-cysteine (CYS) and reduced glutathione (GSH) thiols were oxidized on cobalt tetra ethoxythiophene and cobalt tetra phenoxy pyrrole phthalocyanine modified glassy carbon electrodes, whose catalytic activity was found to depend on pH, film thickness and method of electrode modification. Oxidation of thiocyanate (SCN-), CYS and 2-ME was catalyzed by a selfassembled monolayer of cobalt tetraethoxythiophene Thiocyanate oxidation occurred via two electron transfer, whereas that of CYS and 2-ME required 1 electron. The oxidations of SCN- and 2-ME were catalyzed by ring based processes, while CYS was catalyzed by both Co[superscript III]/Co[superscript II] process and ring-based processes. Oxidation of GSH and 2-ME was conducted on screen printed graphite electrodes modified with cobalt phthalocyanine. Activity depended on method of electrode modification and CoPc % composition. Decomposition of Snitrosoglutathione occurred in the presence of copper ions and NaBH[subscript 4]. Reduced and oxidized glutathione were detected as products using cobalt phthalocyanine adsorbed on an ordinary pyrolytic graphite electrode. Reduction of oxygen was electro-catalyzed by adsorbed manganese phthalocyanine complexes on glassy carbon electrodes. FePc, FePc(Cl)[subscript 16], CoPc and CoPc substituted with phenoxypyrrole and ethoxythiophene ligands were also used as electro-catalysts. Oxygen reduction occurred via two electron transfer in acidic and neutral media forming hydrogen peroxide, while water was formed in basic media via four electron transfer. Cyclohexene oxidation using tert-butylhydroperoxide or chloroperoxy benzoic acid as oxidants in the presence of FePc, FePc(Cl)[subscript 16] and CoPc formed cyclohexene oxide, 2-cyclohexen-1-ol, 2- cyclohexen-1-one and adipic acid. Product selectivity depended on the nature of catalyst and oxidant. The FePc(Cl)[subscript 16] catalyst was transformed into a µ-oxo dimer during the oxidation process while M[superscript III]Pc intermediates were formed with Co[superscript II]Pc and Fe[superscript II]Pc catalysts. Cyclohexene photooxidation catalyzed by zinc phthalocyanine using either red or white light formed 2-cyclohexen-1-one, 2-cyclohexen-1-ol, transcyclohexane diol, cyclohexene oxide and cyclohexene hydroperoxide via singlet oxygen and radical mechanisms. Product yields depended on the light wavelength and intensity, solvent, irradiation time and the rate of photodegradation of the catalyst.
- Full Text:
- Date Issued: 2007
- Authors: Sehlotho, Nthapo
- Date: 2007
- Subjects: Phthalocyanines Photochemistry Electrochemistry Biomimetics Oxidation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4336 , http://hdl.handle.net/10962/d1004997
- Description: This thesis explored use of metallophthalocyanines as electrocatalysts towards thiol and thiocyanate oxidation, nitrosothiol decomposition and reduction of oxygen, as well as biomimetic and photo-catalysts of cyclohexene oxidation. 2-mercaptoethanol (2-ME), L-cysteine (CYS) and reduced glutathione (GSH) thiols were oxidized on cobalt tetra ethoxythiophene and cobalt tetra phenoxy pyrrole phthalocyanine modified glassy carbon electrodes, whose catalytic activity was found to depend on pH, film thickness and method of electrode modification. Oxidation of thiocyanate (SCN-), CYS and 2-ME was catalyzed by a selfassembled monolayer of cobalt tetraethoxythiophene Thiocyanate oxidation occurred via two electron transfer, whereas that of CYS and 2-ME required 1 electron. The oxidations of SCN- and 2-ME were catalyzed by ring based processes, while CYS was catalyzed by both Co[superscript III]/Co[superscript II] process and ring-based processes. Oxidation of GSH and 2-ME was conducted on screen printed graphite electrodes modified with cobalt phthalocyanine. Activity depended on method of electrode modification and CoPc % composition. Decomposition of Snitrosoglutathione occurred in the presence of copper ions and NaBH[subscript 4]. Reduced and oxidized glutathione were detected as products using cobalt phthalocyanine adsorbed on an ordinary pyrolytic graphite electrode. Reduction of oxygen was electro-catalyzed by adsorbed manganese phthalocyanine complexes on glassy carbon electrodes. FePc, FePc(Cl)[subscript 16], CoPc and CoPc substituted with phenoxypyrrole and ethoxythiophene ligands were also used as electro-catalysts. Oxygen reduction occurred via two electron transfer in acidic and neutral media forming hydrogen peroxide, while water was formed in basic media via four electron transfer. Cyclohexene oxidation using tert-butylhydroperoxide or chloroperoxy benzoic acid as oxidants in the presence of FePc, FePc(Cl)[subscript 16] and CoPc formed cyclohexene oxide, 2-cyclohexen-1-ol, 2- cyclohexen-1-one and adipic acid. Product selectivity depended on the nature of catalyst and oxidant. The FePc(Cl)[subscript 16] catalyst was transformed into a µ-oxo dimer during the oxidation process while M[superscript III]Pc intermediates were formed with Co[superscript II]Pc and Fe[superscript II]Pc catalysts. Cyclohexene photooxidation catalyzed by zinc phthalocyanine using either red or white light formed 2-cyclohexen-1-one, 2-cyclohexen-1-ol, transcyclohexane diol, cyclohexene oxide and cyclohexene hydroperoxide via singlet oxygen and radical mechanisms. Product yields depended on the light wavelength and intensity, solvent, irradiation time and the rate of photodegradation of the catalyst.
- Full Text:
- Date Issued: 2007
Population structure, growth and recruitment of two exploited infralittoral molluscs (Haliotis midae and Turbo sarmaticus) along the south east coast, South Africa
- Authors: Proudfoot, Lee-Anne
- Date: 2007
- Subjects: Abalones -- South Africa , Abalones -- Growth -- South Africa , Turbinidae -- South Africa , Mollusks -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5744 , http://hdl.handle.net/10962/d1005430 , Abalones -- South Africa , Abalones -- Growth -- South Africa , Turbinidae -- South Africa , Mollusks -- South Africa
- Description: The two most frequently exploited species along the south east coast of South Africa are the gastropods, Haliotis midae (abalone) and Turbo sarmaticus (alikreukel). H. midae is a high valued commercial species, and suffers intense levels of illegal fishing. T. sarmaticus however, has no commercial value but is the preferred food item for impoverished subsistence communities. Owing to the fact that no legal commercial fishery exists for either species along the south coast, very few studies have been undertaken, especially in the heavily exploited infralittoral. Infralittoral size frequency distributions for both species revealed significant variation in density and size among sites of varying exploitation pressure. Densities ranged between 0 – 2.23 m⁻² (H. midae) and 0.03 – 4.93 m⁻² (T. sarmaticus) and maximum shell lengths ranged from 49.4 – 153.5 mm (H. midae) and 28.3 – 104.4 mm (T. sarmaticus). Relatively high densities and large sizes were found in marine reserves and secluded areas, and low densities and small sizes at sites near to large population centres and within the former Ciskei homeland region. Mean size of the largest 10% of the population, total density and sexually mature density were significantly related to exploitation predictors for both species. In addition, densities of H. midae juveniles were significantly related to exploitation predictors, suggesting that recruitment may be suppressed at the most exploited sites. Exploitation of T. sarmaticus tended to be localized with refuge and subtidal populations persisting. H. midae exploitation was however, far more extensive and intense. Growth of H. midae was investigated using three methods; mark-recapture, cohort analysis and growth banding analysis at Kowie Rocks, Port Alfred. The most useful of these methods for determining growth was a new technique described for growth banding analysis; which was validated using cohort analysis and measurements of shells of known age. This technique was less time consuming and labour intensive than previously described methods. Abalone growth was best described by the Schnute (1981) growth function. Systematic geographic variation in growth was observed for 10 sites along the South African coastline. Significant differences in growth among sites existed for animals between 0-4 years (P < 0.0001) and 4-6 years (P < 0.0001), and in the mean maximum sizes attained (P < 0.001). In general, abalone from the south east/east coast were found to have faster growth rates, smaller mean maximum sizes and attained sexual maturity earlier than those along the south west/ west coast. Haliotis midae recruit and juvenile densities were found to differ significantly among sites of varying exploitation pressure (P < 0.0001) and among months for recruit densities (P < 0.001). Exploited sites had low recruit and juvenile densities compared to unexploited sites and peak recruitment occurred during October/ November 2005. Recruit densities were significantly related to infralittoral adult densities during two of the three sampling months (P<0.05), when recruitment was low. No relationship was observed during the period of high recruitment, with all sites receiving high recruit densities. It was concluded that variation in recruit densities was the result of a combination of both density-dependent relationships (i.e. local spawner density and temporal variability in recruitment intensity) and the possible dispersal capabilities of H. midae. In addition, it was concluded that at present recruitment overfishing was not occurring along the south east coast. Post-recruitment mortality rates were variable but relatively constant, with hypothetical percentage survival and density curves revealing high rates and similar mortality curves among sites. Variation in juvenile densities was consequently a result of initial recruit densities and not variation in post-recruitment mortality. T. sarmaticus populations were found to be regionally sustainable and persisted along the south east coast due to adjacent intertidal and subtidal refuge populations. However, H. midae populations are becoming decimated along the south east coast. From the information obtained in this study new management proposals were suggested and discussed, such as closed areas and region-based management fisheries together with stock enhancement. These suggestions may prove to be feasible alternatives to present management strategies.
- Full Text:
- Date Issued: 2007
- Authors: Proudfoot, Lee-Anne
- Date: 2007
- Subjects: Abalones -- South Africa , Abalones -- Growth -- South Africa , Turbinidae -- South Africa , Mollusks -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5744 , http://hdl.handle.net/10962/d1005430 , Abalones -- South Africa , Abalones -- Growth -- South Africa , Turbinidae -- South Africa , Mollusks -- South Africa
- Description: The two most frequently exploited species along the south east coast of South Africa are the gastropods, Haliotis midae (abalone) and Turbo sarmaticus (alikreukel). H. midae is a high valued commercial species, and suffers intense levels of illegal fishing. T. sarmaticus however, has no commercial value but is the preferred food item for impoverished subsistence communities. Owing to the fact that no legal commercial fishery exists for either species along the south coast, very few studies have been undertaken, especially in the heavily exploited infralittoral. Infralittoral size frequency distributions for both species revealed significant variation in density and size among sites of varying exploitation pressure. Densities ranged between 0 – 2.23 m⁻² (H. midae) and 0.03 – 4.93 m⁻² (T. sarmaticus) and maximum shell lengths ranged from 49.4 – 153.5 mm (H. midae) and 28.3 – 104.4 mm (T. sarmaticus). Relatively high densities and large sizes were found in marine reserves and secluded areas, and low densities and small sizes at sites near to large population centres and within the former Ciskei homeland region. Mean size of the largest 10% of the population, total density and sexually mature density were significantly related to exploitation predictors for both species. In addition, densities of H. midae juveniles were significantly related to exploitation predictors, suggesting that recruitment may be suppressed at the most exploited sites. Exploitation of T. sarmaticus tended to be localized with refuge and subtidal populations persisting. H. midae exploitation was however, far more extensive and intense. Growth of H. midae was investigated using three methods; mark-recapture, cohort analysis and growth banding analysis at Kowie Rocks, Port Alfred. The most useful of these methods for determining growth was a new technique described for growth banding analysis; which was validated using cohort analysis and measurements of shells of known age. This technique was less time consuming and labour intensive than previously described methods. Abalone growth was best described by the Schnute (1981) growth function. Systematic geographic variation in growth was observed for 10 sites along the South African coastline. Significant differences in growth among sites existed for animals between 0-4 years (P < 0.0001) and 4-6 years (P < 0.0001), and in the mean maximum sizes attained (P < 0.001). In general, abalone from the south east/east coast were found to have faster growth rates, smaller mean maximum sizes and attained sexual maturity earlier than those along the south west/ west coast. Haliotis midae recruit and juvenile densities were found to differ significantly among sites of varying exploitation pressure (P < 0.0001) and among months for recruit densities (P < 0.001). Exploited sites had low recruit and juvenile densities compared to unexploited sites and peak recruitment occurred during October/ November 2005. Recruit densities were significantly related to infralittoral adult densities during two of the three sampling months (P<0.05), when recruitment was low. No relationship was observed during the period of high recruitment, with all sites receiving high recruit densities. It was concluded that variation in recruit densities was the result of a combination of both density-dependent relationships (i.e. local spawner density and temporal variability in recruitment intensity) and the possible dispersal capabilities of H. midae. In addition, it was concluded that at present recruitment overfishing was not occurring along the south east coast. Post-recruitment mortality rates were variable but relatively constant, with hypothetical percentage survival and density curves revealing high rates and similar mortality curves among sites. Variation in juvenile densities was consequently a result of initial recruit densities and not variation in post-recruitment mortality. T. sarmaticus populations were found to be regionally sustainable and persisted along the south east coast due to adjacent intertidal and subtidal refuge populations. However, H. midae populations are becoming decimated along the south east coast. From the information obtained in this study new management proposals were suggested and discussed, such as closed areas and region-based management fisheries together with stock enhancement. These suggestions may prove to be feasible alternatives to present management strategies.
- Full Text:
- Date Issued: 2007
Preface to Rhodes University Research Report, 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7654 , http://hdl.handle.net/10962/d1015782
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7654 , http://hdl.handle.net/10962/d1015782
- Full Text:
- Date Issued: 2007
Pricing exotic options using C++
- Authors: Nhongo, Tawuya D R
- Date: 2007
- Subjects: C++ (Computer program language) , Monte Carlo method , Simulation methods , Options (Finance) -- Mathematical models , Pricing -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5577 , http://hdl.handle.net/10962/d1008373 , C++ (Computer program language) , Monte Carlo method , Simulation methods , Options (Finance) -- Mathematical models , Pricing -- Mathematical models
- Description: This document demonstrates the use of the C++ programming language as a simulation tool in the efficient pricing of exotic European options. Extensions to the basic problem of simulation pricing are undertaken including variance reduction by conditional expectation, control and antithetic variates. Ultimately we were able to produce a modularized, easily extend-able program which effectively makes use of Monte Carlo simulation techniques to price lookback, Asian and barrier exotic options. Theories of variance reduction were validated except in cases where we used control variates in combination with the other variance reduction techniques in which case we observed increased variance. Again, the main aim of this half thesis was to produce a C++ program which would produce stable pricings of exotic options.
- Full Text:
- Date Issued: 2007
- Authors: Nhongo, Tawuya D R
- Date: 2007
- Subjects: C++ (Computer program language) , Monte Carlo method , Simulation methods , Options (Finance) -- Mathematical models , Pricing -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5577 , http://hdl.handle.net/10962/d1008373 , C++ (Computer program language) , Monte Carlo method , Simulation methods , Options (Finance) -- Mathematical models , Pricing -- Mathematical models
- Description: This document demonstrates the use of the C++ programming language as a simulation tool in the efficient pricing of exotic European options. Extensions to the basic problem of simulation pricing are undertaken including variance reduction by conditional expectation, control and antithetic variates. Ultimately we were able to produce a modularized, easily extend-able program which effectively makes use of Monte Carlo simulation techniques to price lookback, Asian and barrier exotic options. Theories of variance reduction were validated except in cases where we used control variates in combination with the other variance reduction techniques in which case we observed increased variance. Again, the main aim of this half thesis was to produce a C++ program which would produce stable pricings of exotic options.
- Full Text:
- Date Issued: 2007
Public sector industrial relations in the context of alliance politics: the case of Makana Local Municipality, South Africa (1994-2006)
- Authors: Makwembere, Sandra
- Date: 2007
- Subjects: Makana Municipality , South African Municipal Workers Union , African National Congress , Cosatu , South African Communist Party , Local government -- South Africa -- Eastern Cape , Industrial relations -- South Africa -- Eastern Cape , Labor unions -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3301 , http://hdl.handle.net/10962/d1003089 , Makana Municipality , South African Municipal Workers Union , African National Congress , Cosatu , South African Communist Party , Local government -- South Africa -- Eastern Cape , Industrial relations -- South Africa -- Eastern Cape , Labor unions -- South Africa , South Africa -- Politics and government -- 1994-
- Description: This thesis is in the field of Industrial Relations. It concerns a micro-level investigation of the dynamics of public sector industrial relations in post-apartheid South Africa. It focuses on the Tripartite Alliance between the African National Congress (ANC), the South African Communist Party (SACP) and the Congress of South African Trade Unions (COSATU) and explores what the Alliance relationship has meant for the traditional roles of employees and their representatives on the one hand, and employers and their representatives on the other. The thesis examines the political, organisational and societal contradictions and implications for COSATU public sector union affiliates and their members in their relationship to the ANC as an ally (via the Alliance) and the context in which ANC members form part of management (in government). The South African Municipal Workers’ Union (SAMWU) was used as an archetype of a COSATU public sector union affiliate that engages with the State as employer at the municipal level. It is a case study of Makana Local Municipality (Eastern Cape Province, South Africa) using qualitative research techniques and content analysis to derive the relevant information. The author conducted a series of in-depth interviews of key informants and observations at Makana Local Municipality were done. Based on the empirical data obtained from the investigation, the thesis argues that the traditional roles in the employment relationship at the workplace have been affected by the political alliance. Industrial relations roles have become increasingly vague especially since many within local government share ANC/SACP memberships with members of the trade union. The study also highlights that within an increasingly globalising post-apartheid environment, the Alliance provides mixture of benefits and challenges for workplace negotiations and employment relations in ways that macro-level analyses of employer-employee relationships do not always capture.
- Full Text:
- Date Issued: 2007
- Authors: Makwembere, Sandra
- Date: 2007
- Subjects: Makana Municipality , South African Municipal Workers Union , African National Congress , Cosatu , South African Communist Party , Local government -- South Africa -- Eastern Cape , Industrial relations -- South Africa -- Eastern Cape , Labor unions -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3301 , http://hdl.handle.net/10962/d1003089 , Makana Municipality , South African Municipal Workers Union , African National Congress , Cosatu , South African Communist Party , Local government -- South Africa -- Eastern Cape , Industrial relations -- South Africa -- Eastern Cape , Labor unions -- South Africa , South Africa -- Politics and government -- 1994-
- Description: This thesis is in the field of Industrial Relations. It concerns a micro-level investigation of the dynamics of public sector industrial relations in post-apartheid South Africa. It focuses on the Tripartite Alliance between the African National Congress (ANC), the South African Communist Party (SACP) and the Congress of South African Trade Unions (COSATU) and explores what the Alliance relationship has meant for the traditional roles of employees and their representatives on the one hand, and employers and their representatives on the other. The thesis examines the political, organisational and societal contradictions and implications for COSATU public sector union affiliates and their members in their relationship to the ANC as an ally (via the Alliance) and the context in which ANC members form part of management (in government). The South African Municipal Workers’ Union (SAMWU) was used as an archetype of a COSATU public sector union affiliate that engages with the State as employer at the municipal level. It is a case study of Makana Local Municipality (Eastern Cape Province, South Africa) using qualitative research techniques and content analysis to derive the relevant information. The author conducted a series of in-depth interviews of key informants and observations at Makana Local Municipality were done. Based on the empirical data obtained from the investigation, the thesis argues that the traditional roles in the employment relationship at the workplace have been affected by the political alliance. Industrial relations roles have become increasingly vague especially since many within local government share ANC/SACP memberships with members of the trade union. The study also highlights that within an increasingly globalising post-apartheid environment, the Alliance provides mixture of benefits and challenges for workplace negotiations and employment relations in ways that macro-level analyses of employer-employee relationships do not always capture.
- Full Text:
- Date Issued: 2007
Race against democracy: a case study of the Mail & Guardian during the early years of the Mbeki presidency, 1999-2002
- Authors: Steenveld, Lynette Noreen
- Date: 2007
- Subjects: Mbeki, Thabo -- In mass media , Mail & Guardian , South African newspapers , Press -- South Africa , Press and politics -- South Africa , Journalism -- South Africa , Mass media and race relations -- South Africa , Racism in the press -- South Africa , Mass media -- Political aspects -- South Africa , South Africa -- Politics and government -- 20th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3537 , http://hdl.handle.net/10962/d1015572
- Description: This thesis examines the 1998 complaint of racism against the Mail & Guardian, a leading exponent of South Africa's alternative press in the 1980s, and important contemporary producer of investigative journalism. The study is framed within a cultural studies approach, analysing the Mail & Guardian as constituted by a 'circuit of production': its social context, production, texts, and audiences. The thesis makes three main arguments. First, that the claim of racism cannot be understood outside of a consideration of both the changing political milieu, and subtle changes within the Mail & Guardian itself. Significant social changes relate to the reconfiguration of racial and class identities wrought by the 'Mbeki state'. Within the Mail & Guardian, the thesis argues for the importance of the power and subjectivity of the editor as a key 'factor' shaping the identity of the paper, evidenced in its production practices and textual outputs. In this regard, the thesis departs from a functionalist analysis of particular 'roles' within the newsroom, drawing instead on a post-structuralist approach to organisational studies. Based on this production and social context, the thesis examines key texts which deal with aspects of South Africa's social transformation, and which exemplify aspects of the Mail & Guardian's reporting which led to the complaint of racism by the Black Lawyers Association (BLA) and the Association of Black Accountants (ABASA). Their complaint was that the Mail & Guardian's reporting impugned the dignity of black people, and in so doing was a violation of their rights to dignity and equality which are constitutionally guaranteed. However, as freedom of the press is also guaranteed by the South African constitution, their complaint to the South African Human Rights Commission (SAHRC) resulted in public debate about these contending rights. My second argument relates to the jurisprudential approach to racism, and the related issue of affirmative action, which informed the complaint against the paper. Contrary to the 'normative', liberal approach to these issues, this thesis highlights Critical Race Theory as the jurisprudential basis for both the claimants' accusation of racism against the Mail & Guardian, and aspects of its implicit use in South African human rights adjudication. The thesis argues that in failing to recognise these different philosophical and political bases of legal reasoning, the media, including the Mail & Guardian, in reporting on these matters failed in their purported role of serving the public interest. The thesis concludes by applying Fraser's critique of Habermas's notion of a single, bourgeois public sphere to journalism, thereby suggesting ways in which the critiques of some of the Mail & Guardian's own journalists could be employed to enlarge its approach to journalism - giving voice to constituencies seldom heard in mainstream media.
- Full Text:
- Date Issued: 2007
- Authors: Steenveld, Lynette Noreen
- Date: 2007
- Subjects: Mbeki, Thabo -- In mass media , Mail & Guardian , South African newspapers , Press -- South Africa , Press and politics -- South Africa , Journalism -- South Africa , Mass media and race relations -- South Africa , Racism in the press -- South Africa , Mass media -- Political aspects -- South Africa , South Africa -- Politics and government -- 20th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3537 , http://hdl.handle.net/10962/d1015572
- Description: This thesis examines the 1998 complaint of racism against the Mail & Guardian, a leading exponent of South Africa's alternative press in the 1980s, and important contemporary producer of investigative journalism. The study is framed within a cultural studies approach, analysing the Mail & Guardian as constituted by a 'circuit of production': its social context, production, texts, and audiences. The thesis makes three main arguments. First, that the claim of racism cannot be understood outside of a consideration of both the changing political milieu, and subtle changes within the Mail & Guardian itself. Significant social changes relate to the reconfiguration of racial and class identities wrought by the 'Mbeki state'. Within the Mail & Guardian, the thesis argues for the importance of the power and subjectivity of the editor as a key 'factor' shaping the identity of the paper, evidenced in its production practices and textual outputs. In this regard, the thesis departs from a functionalist analysis of particular 'roles' within the newsroom, drawing instead on a post-structuralist approach to organisational studies. Based on this production and social context, the thesis examines key texts which deal with aspects of South Africa's social transformation, and which exemplify aspects of the Mail & Guardian's reporting which led to the complaint of racism by the Black Lawyers Association (BLA) and the Association of Black Accountants (ABASA). Their complaint was that the Mail & Guardian's reporting impugned the dignity of black people, and in so doing was a violation of their rights to dignity and equality which are constitutionally guaranteed. However, as freedom of the press is also guaranteed by the South African constitution, their complaint to the South African Human Rights Commission (SAHRC) resulted in public debate about these contending rights. My second argument relates to the jurisprudential approach to racism, and the related issue of affirmative action, which informed the complaint against the paper. Contrary to the 'normative', liberal approach to these issues, this thesis highlights Critical Race Theory as the jurisprudential basis for both the claimants' accusation of racism against the Mail & Guardian, and aspects of its implicit use in South African human rights adjudication. The thesis argues that in failing to recognise these different philosophical and political bases of legal reasoning, the media, including the Mail & Guardian, in reporting on these matters failed in their purported role of serving the public interest. The thesis concludes by applying Fraser's critique of Habermas's notion of a single, bourgeois public sphere to journalism, thereby suggesting ways in which the critiques of some of the Mail & Guardian's own journalists could be employed to enlarge its approach to journalism - giving voice to constituencies seldom heard in mainstream media.
- Full Text:
- Date Issued: 2007
Reading the Sowetan's mediation of the public's response to the Jacob Zuma rape trial: a critical discourse analysis
- Authors: Stent, Alison
- Date: 2007
- Subjects: Zuma, Jacob -- Trials, litigation etc Zuma, Jacob -- Public opinion Sowetan (Johannesburg, South Africa) Populism -- South Africa Social choice -- South Africa Social justice -- South Africa Ethnicity -- Political aspects -- South Africa Rape -- Public opinion Women -- Crimes against -- South Africa Sex discrimination against women -- South Africa Trials (Rape) -- South Africa Rape in mass media Crime and the press -- South Africa Mass media and women -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3485 , http://hdl.handle.net/10962/d1002940
- Description: In this minithesis I conduct a critical discourse analysis to take on a double-pronged task. On the one hand I explore the social phenomenon of the contestation between supporters of then-ANC deputy president Jacob Zuma and supporters of his rape accuser. The trial, which took place in the Johannesburg High Court between mid-February and early May 2006, stirred intense public interest, both locally and internationally. The performance of thousands of Zuma’s supporters and a far smaller number of gender rights lobby groups, both of whom kept a presence outside the court building throughout the trial, received similar attention. Second, I examine how the Sowetan, a national daily tabloid with a black, middle-class readership, mediated the trial through pictures of the theatre outside the court and letters to the editor. The study is informed by post-Marxist and cultural studies perspectives, both approaches that are concerned with issues of power, ideology and the circulation of meaning within specific sociocultural contexts. A rudimentary thematic content analysis draws out some of the main themes from the material, while the critical discourse analysis is located within a theoretical framework based on concepts from Laclau & Mouffe’s theory of meaning, which assumes a power struggle between contesting positions seeking to invalidate one another and to either challenge or support existing hegemonies. This is further informed by, first, Laclau’s theorisation of populism, which assumes that diverse groupings can unite under a demagogue’s banner in shared antagonism towards existing power, and second, by concepts from Mamdani’s theorisation of power and resistance in colonial and post-colonial Africa, which explicates three overarching ideological discourses of human rights, social justice and traditional ethnic practices. The study, then, explores how these three discourses were operationalised by the localised contestations over the trial.
- Full Text: false
- Date Issued: 2007
- Authors: Stent, Alison
- Date: 2007
- Subjects: Zuma, Jacob -- Trials, litigation etc Zuma, Jacob -- Public opinion Sowetan (Johannesburg, South Africa) Populism -- South Africa Social choice -- South Africa Social justice -- South Africa Ethnicity -- Political aspects -- South Africa Rape -- Public opinion Women -- Crimes against -- South Africa Sex discrimination against women -- South Africa Trials (Rape) -- South Africa Rape in mass media Crime and the press -- South Africa Mass media and women -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3485 , http://hdl.handle.net/10962/d1002940
- Description: In this minithesis I conduct a critical discourse analysis to take on a double-pronged task. On the one hand I explore the social phenomenon of the contestation between supporters of then-ANC deputy president Jacob Zuma and supporters of his rape accuser. The trial, which took place in the Johannesburg High Court between mid-February and early May 2006, stirred intense public interest, both locally and internationally. The performance of thousands of Zuma’s supporters and a far smaller number of gender rights lobby groups, both of whom kept a presence outside the court building throughout the trial, received similar attention. Second, I examine how the Sowetan, a national daily tabloid with a black, middle-class readership, mediated the trial through pictures of the theatre outside the court and letters to the editor. The study is informed by post-Marxist and cultural studies perspectives, both approaches that are concerned with issues of power, ideology and the circulation of meaning within specific sociocultural contexts. A rudimentary thematic content analysis draws out some of the main themes from the material, while the critical discourse analysis is located within a theoretical framework based on concepts from Laclau & Mouffe’s theory of meaning, which assumes a power struggle between contesting positions seeking to invalidate one another and to either challenge or support existing hegemonies. This is further informed by, first, Laclau’s theorisation of populism, which assumes that diverse groupings can unite under a demagogue’s banner in shared antagonism towards existing power, and second, by concepts from Mamdani’s theorisation of power and resistance in colonial and post-colonial Africa, which explicates three overarching ideological discourses of human rights, social justice and traditional ethnic practices. The study, then, explores how these three discourses were operationalised by the localised contestations over the trial.
- Full Text: false
- Date Issued: 2007
Regulation of hyu gene expression in Agrobacterium tumefaciens strains RU-AE01 and RU-OR
- Authors: Jiwaji, Meesbah
- Date: 2007
- Subjects: Agrobacterium tumefaciens Amino acids Gene expression Hydrolysis Hydantoin Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3983 , http://hdl.handle.net/10962/d1004042
- Description: Several Agrobacterium tumefaciens strains have been isolated for their ability to produce D-amino acids from D, L-substituted hydantoins. The optically pure D-amino acids are used in the synthesis of pharmaceuticals, as food additives and as insecticides. This hydrolysis of D, L-substituted hydantoins is catalysed by two hydantoin-hydrolyzing enzymes, an hydantoinase and an N-carbamyl amino acid amidohydrolase. While the hydantoin-hydrolyzing enzymes have been studied in detail, the mechanisms that control expression of the hyu genes have not. The research reported in this work elucidates some of the mechanisms involved in the regulation of the hyu genes in A. tumefaciens strains. The hydantoin-hydrolyzing enzyme activity from the environmental isolate A. tumefaciens RU-AE01 was characterized. A broad host range vector for the simultaneous analysis of divergent promoters was constructed. The promoter regions responsible for the activation of transcription of hyuH and hyuC were identified by deletion analysis. It was proposed that transcription of hyuH was activated by a putative σ[superscript 54]-dependent promoter or a putative σ[superscript 70]-dependent promoter identified upstream of the hyuH gene. The hyuC gene was activated by a putative σ[superscript 70]-dependent promoter identified upstream of the hyuC gene. The regulation of hydantoinase and N-carbamyl amino acid amidohydrolase enzyme activity was compared to the regulation of transcription from the RU-AE01 hyuH-hyuC region. Expression of the hydantoin-hydrolyzing enzymes was regulated by induction which correlated with reporter enzyme expression from the hyuH and hyuC promoter regions. However, the expression of the hydantoin-hydrolyzing enzymes was also regulated by nitrogen catabolite repression (NCR). This did not correlate to the reporter gene expression of the hyuH promoter region but did compare to the reporter gene expression of the hyuC promoter region. This suggested that NCR of hyuH was at the post-translational level whereas NCR of the hyuC promoter was at the transcriptional level. Pathways involved in the regulation of the hyu genes were characterized. The production of the hydantoin-hydrolyzing enzymes in both A. tumefaciens strains RU-AE01 and RU-OR were regulated by proteins involved in the global ntr pathway. The levels of the hydantoin-hydrolyzing enzymes in strain RU-AE01 were elevated in the presence of increased levels of NtrB and NtrC illustrating the importance of the ntr pathway in the regulation of the levels of the hydantoin-hydrolyzing enzymes. Similarly, in RU-OR the presence of exogenous NtrB and NtrC elevated levels of N-carbamyl amino acid amidohydrolase activity. However, the levels of hydantoinase enzyme activity in strain RU-OR were elevated in the presence of NtrC alone. In addition, the presence of a His6-tagged NtrC molecule abolished the elevation in the levels of the hydantoinase but not the N-carbamyl amino acid amidohydrolase enzyme activity in strain RU-OR. This suggests that NtrC has a direct role in the regulation of the expression of hyuH in RU-OR. In addition, it indicates that the hyu genes in the two A. tumefaciens strains RU-AE01 and RU-OR are different. The presence of the RU-AE01 hyuH-hyuC fragment caused a dramatic increase in the hydantoin-hydrolyzing enzyme activity in strain RU-OR but not strain RU-AE01. This implied the incidence of a possible repressor protein in RU-OR, which is titrated out by the presence of the RU-AE01 hyuH-hyuC fragment. Protein-DNA binding assays suggest that this putative repressor may be 38 kDa in RU-OR cells.
- Full Text:
- Date Issued: 2007
- Authors: Jiwaji, Meesbah
- Date: 2007
- Subjects: Agrobacterium tumefaciens Amino acids Gene expression Hydrolysis Hydantoin Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3983 , http://hdl.handle.net/10962/d1004042
- Description: Several Agrobacterium tumefaciens strains have been isolated for their ability to produce D-amino acids from D, L-substituted hydantoins. The optically pure D-amino acids are used in the synthesis of pharmaceuticals, as food additives and as insecticides. This hydrolysis of D, L-substituted hydantoins is catalysed by two hydantoin-hydrolyzing enzymes, an hydantoinase and an N-carbamyl amino acid amidohydrolase. While the hydantoin-hydrolyzing enzymes have been studied in detail, the mechanisms that control expression of the hyu genes have not. The research reported in this work elucidates some of the mechanisms involved in the regulation of the hyu genes in A. tumefaciens strains. The hydantoin-hydrolyzing enzyme activity from the environmental isolate A. tumefaciens RU-AE01 was characterized. A broad host range vector for the simultaneous analysis of divergent promoters was constructed. The promoter regions responsible for the activation of transcription of hyuH and hyuC were identified by deletion analysis. It was proposed that transcription of hyuH was activated by a putative σ[superscript 54]-dependent promoter or a putative σ[superscript 70]-dependent promoter identified upstream of the hyuH gene. The hyuC gene was activated by a putative σ[superscript 70]-dependent promoter identified upstream of the hyuC gene. The regulation of hydantoinase and N-carbamyl amino acid amidohydrolase enzyme activity was compared to the regulation of transcription from the RU-AE01 hyuH-hyuC region. Expression of the hydantoin-hydrolyzing enzymes was regulated by induction which correlated with reporter enzyme expression from the hyuH and hyuC promoter regions. However, the expression of the hydantoin-hydrolyzing enzymes was also regulated by nitrogen catabolite repression (NCR). This did not correlate to the reporter gene expression of the hyuH promoter region but did compare to the reporter gene expression of the hyuC promoter region. This suggested that NCR of hyuH was at the post-translational level whereas NCR of the hyuC promoter was at the transcriptional level. Pathways involved in the regulation of the hyu genes were characterized. The production of the hydantoin-hydrolyzing enzymes in both A. tumefaciens strains RU-AE01 and RU-OR were regulated by proteins involved in the global ntr pathway. The levels of the hydantoin-hydrolyzing enzymes in strain RU-AE01 were elevated in the presence of increased levels of NtrB and NtrC illustrating the importance of the ntr pathway in the regulation of the levels of the hydantoin-hydrolyzing enzymes. Similarly, in RU-OR the presence of exogenous NtrB and NtrC elevated levels of N-carbamyl amino acid amidohydrolase activity. However, the levels of hydantoinase enzyme activity in strain RU-OR were elevated in the presence of NtrC alone. In addition, the presence of a His6-tagged NtrC molecule abolished the elevation in the levels of the hydantoinase but not the N-carbamyl amino acid amidohydrolase enzyme activity in strain RU-OR. This suggests that NtrC has a direct role in the regulation of the expression of hyuH in RU-OR. In addition, it indicates that the hyu genes in the two A. tumefaciens strains RU-AE01 and RU-OR are different. The presence of the RU-AE01 hyuH-hyuC fragment caused a dramatic increase in the hydantoin-hydrolyzing enzyme activity in strain RU-OR but not strain RU-AE01. This implied the incidence of a possible repressor protein in RU-OR, which is titrated out by the presence of the RU-AE01 hyuH-hyuC fragment. Protein-DNA binding assays suggest that this putative repressor may be 38 kDa in RU-OR cells.
- Full Text:
- Date Issued: 2007
Relating indigenous knowledge practices and science concepts : an exploratory case study in a secondary school teacher-training programme
- Authors: Mandikonza, Caleb
- Date: 2007
- Subjects: Ethnoscience -- Study and teaching (Secondary) -- Zimbabwe Science -- Study and teaching (Secondary) -- Zimbabwe Teachers -- Training of -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1918 , http://hdl.handle.net/10962/d1007321
- Description: This study reports research on how student teachers in Science at Mutare Teachers' College in Zimbabwe worked with indigenous knowledge practices in relation to science concepts in the secondary school syllabus. The study was conducted among first-year science students and involved them in developing science learning activities for a peer-teaching process that was part of their course. The research was undertaken during a review ofthe college syllabus and as a study to inform the Secondary Teacher Training Environmental Education Programme (ST²EEP). The research design involved the researcher in participant observations and interviews with rural people to document indigenous knowledge practices and to develop materials for the students to work with in the lessons design part of the study. The student teachers used the documented practices to generate learning activities and lesson plans to teach the science concepts they had identified. A peer review session and focus group interviews followed the lesson presentations. Findings from the research point to the rural community being a repository of diverse indigenous knowledge practices. Student teachers showed that they had prior knowledge of both indigenous knowledge practices and science concepts when they come to class. Student teachers were able to relate indigenous knowledge practices and science concepts in ways that have the potential to enhance the learning of science in rural school contexts that lack laboratories and science equipment. The scope of the study does not allow for anything beyond tentative conclusions that point to the need for further work to be undertaken with student teachers and for the research to be extended to teaching and learning interactions in schools. Recommendations are also made for further resource-based work to be undertaken within the forthcoming St²eep implementation phase in 2007.
- Full Text:
- Date Issued: 2007
- Authors: Mandikonza, Caleb
- Date: 2007
- Subjects: Ethnoscience -- Study and teaching (Secondary) -- Zimbabwe Science -- Study and teaching (Secondary) -- Zimbabwe Teachers -- Training of -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1918 , http://hdl.handle.net/10962/d1007321
- Description: This study reports research on how student teachers in Science at Mutare Teachers' College in Zimbabwe worked with indigenous knowledge practices in relation to science concepts in the secondary school syllabus. The study was conducted among first-year science students and involved them in developing science learning activities for a peer-teaching process that was part of their course. The research was undertaken during a review ofthe college syllabus and as a study to inform the Secondary Teacher Training Environmental Education Programme (ST²EEP). The research design involved the researcher in participant observations and interviews with rural people to document indigenous knowledge practices and to develop materials for the students to work with in the lessons design part of the study. The student teachers used the documented practices to generate learning activities and lesson plans to teach the science concepts they had identified. A peer review session and focus group interviews followed the lesson presentations. Findings from the research point to the rural community being a repository of diverse indigenous knowledge practices. Student teachers showed that they had prior knowledge of both indigenous knowledge practices and science concepts when they come to class. Student teachers were able to relate indigenous knowledge practices and science concepts in ways that have the potential to enhance the learning of science in rural school contexts that lack laboratories and science equipment. The scope of the study does not allow for anything beyond tentative conclusions that point to the need for further work to be undertaken with student teachers and for the research to be extended to teaching and learning interactions in schools. Recommendations are also made for further resource-based work to be undertaken within the forthcoming St²eep implementation phase in 2007.
- Full Text:
- Date Issued: 2007
Reviewing the use of environmental audits for environmental learning in school contexts: a case study of environmental auditing processes within a professional development course
- Authors: Hoffmann, Patricia Anne
- Date: 2007
- Subjects: Environmental auditing -- Study and teaching -- South Africa -- Case studies Environmental education -- South Africa -- Case studies Sustainable development -- Study and teaching -- South Africa -- Case studies Professional education -- South Africa -- Case studies Teachers -- Training of -- South Africa -- Case studies Educational change -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1746 , http://hdl.handle.net/10962/d1003630
- Description: This case study focuses on the use of environmental audits for learning, by teachers participating in the Schools and Sustainability professional development course in Durban, South Africa. It reviews ways in which audits were choreographed and used for lessons within school contexts. It explores ways in which audits shaped meaning-making interactions and environmental learning processes. This is an interpretive case study, characterized by a moderate realist perspective. Data were generated through interviews with teachers, field observations, photographs, document analysis, and group interviews with learners. Data were analyzed using the general comparative method. The research takes place in the context of educational transformation in South Africa. Some of the challenges accompanying the shift to Outcomes Based Education seem to be associated with naïve interpretations of constructivism and a view of reality as socially constructed and relative. This seems to have influenced ways in which audits are being undertaken in school contexts. This study argues that a realist orientation to auditing may be a more useful process for engaging with the world and enhancing the way learners perceive and respond to environmental risk. Ideas about reality-congruence and the interacting processes of involvement and detachment are of central importance in understanding processes of knowledge construction and meaning making in this study. The study draws on the work of Elias (1987) and Latour (1999) to shed light on the significance of auditing processes in which a close engagement with reality, coupled with a measure of detachment, can lead to the construction of a more reality-congruent account and a more realistic assessment of the environmental issue in focus. Key findings of the study suggest that the effectiveness of environmental auditing as a pedagogical process was influenced by the teachers’ intentions, knowledge and skills, choreography of the audit, nature of the teaching and learning interactions, and ways in which teachers and learners engaged with the findings. The study recommends that auditing activities should be carefully structured and mediated by teachers to be meaningful and to enable learners to identify environmental issues, gather data, engage in critical reflection and deliberate appropriate responses for social and environmental transformation.
- Full Text:
- Date Issued: 2007
- Authors: Hoffmann, Patricia Anne
- Date: 2007
- Subjects: Environmental auditing -- Study and teaching -- South Africa -- Case studies Environmental education -- South Africa -- Case studies Sustainable development -- Study and teaching -- South Africa -- Case studies Professional education -- South Africa -- Case studies Teachers -- Training of -- South Africa -- Case studies Educational change -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1746 , http://hdl.handle.net/10962/d1003630
- Description: This case study focuses on the use of environmental audits for learning, by teachers participating in the Schools and Sustainability professional development course in Durban, South Africa. It reviews ways in which audits were choreographed and used for lessons within school contexts. It explores ways in which audits shaped meaning-making interactions and environmental learning processes. This is an interpretive case study, characterized by a moderate realist perspective. Data were generated through interviews with teachers, field observations, photographs, document analysis, and group interviews with learners. Data were analyzed using the general comparative method. The research takes place in the context of educational transformation in South Africa. Some of the challenges accompanying the shift to Outcomes Based Education seem to be associated with naïve interpretations of constructivism and a view of reality as socially constructed and relative. This seems to have influenced ways in which audits are being undertaken in school contexts. This study argues that a realist orientation to auditing may be a more useful process for engaging with the world and enhancing the way learners perceive and respond to environmental risk. Ideas about reality-congruence and the interacting processes of involvement and detachment are of central importance in understanding processes of knowledge construction and meaning making in this study. The study draws on the work of Elias (1987) and Latour (1999) to shed light on the significance of auditing processes in which a close engagement with reality, coupled with a measure of detachment, can lead to the construction of a more reality-congruent account and a more realistic assessment of the environmental issue in focus. Key findings of the study suggest that the effectiveness of environmental auditing as a pedagogical process was influenced by the teachers’ intentions, knowledge and skills, choreography of the audit, nature of the teaching and learning interactions, and ways in which teachers and learners engaged with the findings. The study recommends that auditing activities should be carefully structured and mediated by teachers to be meaningful and to enable learners to identify environmental issues, gather data, engage in critical reflection and deliberate appropriate responses for social and environmental transformation.
- Full Text:
- Date Issued: 2007
Rhodes University 2007 Graduation Ceremonies Address
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: Text
- Identifier: vital:7628 , http://hdl.handle.net/10962/d1012595
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: Text
- Identifier: vital:7628 , http://hdl.handle.net/10962/d1012595
- Full Text:
- Date Issued: 2007
Rhodes University : into 2007 and beyond
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7655 , http://hdl.handle.net/10962/d1015783
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7655 , http://hdl.handle.net/10962/d1015783
- Full Text:
- Date Issued: 2007
Rhodes University Graduation Ceremony 2007
- Authors: Rhodes University
- Date: 2007
- Language: English
- Type: text
- Identifier: vital:8140 , http://hdl.handle.net/10962/d1007252
- Description: Rhodes University Graduation Ceremonies 1820 Settlers National Monument Thursday, 12 April 2007 at 18:00 [and] Friday, 13 April 2007 at 10:30; 14:30 & 18:00 [and] Saturday, 14 April 2007 at 10:30
- Full Text:
- Date Issued: 2007
- Authors: Rhodes University
- Date: 2007
- Language: English
- Type: text
- Identifier: vital:8140 , http://hdl.handle.net/10962/d1007252
- Description: Rhodes University Graduation Ceremonies 1820 Settlers National Monument Thursday, 12 April 2007 at 18:00 [and] Friday, 13 April 2007 at 10:30; 14:30 & 18:00 [and] Saturday, 14 April 2007 at 10:30
- Full Text:
- Date Issued: 2007
Rhodes University Orientation Week : Welcome address of the vice-chancellor of Rhodes University, Dr Saleem Badat, 5 February 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7651 , http://hdl.handle.net/10962/d1015779
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7651 , http://hdl.handle.net/10962/d1015779
- Full Text:
- Date Issued: 2007
Rhodes University postgraduates orientation welcome, 9 Feb 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7653 , http://hdl.handle.net/10962/d1015781
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7653 , http://hdl.handle.net/10962/d1015781
- Full Text:
- Date Issued: 2007
Roles : "I am as intently observed as the people photograph"
- Authors: Pelser, Monique Myren
- Date: 2007
- Subjects: Hugo, Pieter Portrait photography Self-portraits Photography, Artistic -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2457 , http://hdl.handle.net/10962/d1007647
- Description: With this dissertation I propose an investigation of how the photographic portrait attempts to construct and confirm identity through the representation of types. Drawing from theoretical texts by Roland Barthes and Robert Sobieszek and engaging with my own process of self-portraiture, as a means of troubling the usual power relations involved between the photographer and the sitter, I will demonstrate the dialectical nature of these roles involved in photographic portraiture. Looking at Pieter Hugo's portraits of judges in Botswana permits me to deal with issues of masquerade and how fashions and uniforms mask an individual allowing him/her to perform roles and stereotypes in society. Referring to another set of Hugo's images from his ongoing series Looking Aside, I will explore the paradoxical nature of the portrait through the dialectic of the 'self 'and 'other' subject and object split through an exploration of notions of skin and prosthetic skin and the relationship to the liminal space 'opened' between subject and object, or viewer and image.
- Full Text:
- Date Issued: 2007
- Authors: Pelser, Monique Myren
- Date: 2007
- Subjects: Hugo, Pieter Portrait photography Self-portraits Photography, Artistic -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2457 , http://hdl.handle.net/10962/d1007647
- Description: With this dissertation I propose an investigation of how the photographic portrait attempts to construct and confirm identity through the representation of types. Drawing from theoretical texts by Roland Barthes and Robert Sobieszek and engaging with my own process of self-portraiture, as a means of troubling the usual power relations involved between the photographer and the sitter, I will demonstrate the dialectical nature of these roles involved in photographic portraiture. Looking at Pieter Hugo's portraits of judges in Botswana permits me to deal with issues of masquerade and how fashions and uniforms mask an individual allowing him/her to perform roles and stereotypes in society. Referring to another set of Hugo's images from his ongoing series Looking Aside, I will explore the paradoxical nature of the portrait through the dialectic of the 'self 'and 'other' subject and object split through an exploration of notions of skin and prosthetic skin and the relationship to the liminal space 'opened' between subject and object, or viewer and image.
- Full Text:
- Date Issued: 2007