Investigating the roles of HOP isoforms in KSHV biology
- Matandirotya, Lorraine Tariro
- Authors: Matandirotya, Lorraine Tariro
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365257 , vital:65721
- Description: Thesis embargoed. Possible release date set for early 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Matandirotya, Lorraine Tariro
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365257 , vital:65721
- Description: Thesis embargoed. Possible release date set for early 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
Human FN1 is regulated by the heat-shock response
- Authors: Dhanani, Karim Colin Hassan
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193487 , vital:45336
- Description: Heat shock protein 90 (Hsp90) and heat shock factors (HSFs) are known to be involved in the epigenetic regulation of several fundamental oncogenic genes. Fibronectin (FN) is an extracellular matrix (ECM) glycoprotein which plays key roles in cell adhesion and migration. Hsp90 binds directly to FN and Hsp90 inhibition has been shown to regulate FN protein levels and matrix formation. Where inhibition of Hsp90 with a C-terminal inhibitor (novobiocin) induced the loss of FN matrix, treatment with an N-terminal inhibitor (geldanamycin) increased FN matrix levels. GA treatment induced a strong dose and time dependent increase in FN1 promoter activity and increased total FN mRNA respectively. By contrast, NOV showed no increase in the promoter activity and no change in the expression of FN mRNA. As GA is known to induce the stress response, we investigated the relationship between the cell stress machinery and the transcriptional regulation of FN. Three putative heat shock elements (HSEs) were identified in the FN1 promoter. The loss of two of the three identified putative HSEs resulted in a loss in the basal transcriptional activity of the FN1 promoter in our reporter model. This was in addition to the loss of the induction of transcriptional activity with GA treatment observed with the full-length promoter. Binding of HSF1 to one of the putative HSEs, which was identified as potentially functional from the truncation analysis, was confirmed using ChIP. The occupancy of this HSE by HSF1 was shown to increase with GA treatment. These data support the hypothesis that FN1 is a functional HSF1 target gene. The 5' promoter regions of seven additional ECM protein encoding genes were analysed and mRNA levels were detected by quantitative RT-PCR upon treatment with GA. Collagen 4 _2 and laminin _3 mRNA were found to increase in the presence of GA, whereas collagen 4 _3 and osteopontin showed no change. Similarly to FN1, these data indicate that a subset of ECM genes may be under the regulation of the HSF1 mediated heat-shock response. This may have implications for our understanding of ECM dynamics in cancer, where the clinical application of Hsp90 inhibitors is intended. Additionally, our data provide a poten- tial underpinning for the role of the HSF1 mediated heat-shock response in several fibrotic and metabolic stress related pathologies. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
- Authors: Dhanani, Karim Colin Hassan
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193487 , vital:45336
- Description: Heat shock protein 90 (Hsp90) and heat shock factors (HSFs) are known to be involved in the epigenetic regulation of several fundamental oncogenic genes. Fibronectin (FN) is an extracellular matrix (ECM) glycoprotein which plays key roles in cell adhesion and migration. Hsp90 binds directly to FN and Hsp90 inhibition has been shown to regulate FN protein levels and matrix formation. Where inhibition of Hsp90 with a C-terminal inhibitor (novobiocin) induced the loss of FN matrix, treatment with an N-terminal inhibitor (geldanamycin) increased FN matrix levels. GA treatment induced a strong dose and time dependent increase in FN1 promoter activity and increased total FN mRNA respectively. By contrast, NOV showed no increase in the promoter activity and no change in the expression of FN mRNA. As GA is known to induce the stress response, we investigated the relationship between the cell stress machinery and the transcriptional regulation of FN. Three putative heat shock elements (HSEs) were identified in the FN1 promoter. The loss of two of the three identified putative HSEs resulted in a loss in the basal transcriptional activity of the FN1 promoter in our reporter model. This was in addition to the loss of the induction of transcriptional activity with GA treatment observed with the full-length promoter. Binding of HSF1 to one of the putative HSEs, which was identified as potentially functional from the truncation analysis, was confirmed using ChIP. The occupancy of this HSE by HSF1 was shown to increase with GA treatment. These data support the hypothesis that FN1 is a functional HSF1 target gene. The 5' promoter regions of seven additional ECM protein encoding genes were analysed and mRNA levels were detected by quantitative RT-PCR upon treatment with GA. Collagen 4 _2 and laminin _3 mRNA were found to increase in the presence of GA, whereas collagen 4 _3 and osteopontin showed no change. Similarly to FN1, these data indicate that a subset of ECM genes may be under the regulation of the HSF1 mediated heat-shock response. This may have implications for our understanding of ECM dynamics in cancer, where the clinical application of Hsp90 inhibitors is intended. Additionally, our data provide a poten- tial underpinning for the role of the HSF1 mediated heat-shock response in several fibrotic and metabolic stress related pathologies. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
Regulation of Oct4 expression during cell stress
- Authors: Samson, William John
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365712 , vital:65778
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Samson, William John
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365712 , vital:65778
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
Volatility spillovers and determinants of contagion: a case of BRICS equity and foreign exchange markets
- Authors: Nyopa, Tšepiso
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MCOM
- Identifier: http://hdl.handle.net/10962/164590 , vital:41146
- Description: Thesis (MSc)--Rhodes University, Faculty of Commerce, Economics and Economic History, 2020
- Full Text:
- Date Issued: 2020
- Authors: Nyopa, Tšepiso
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MCOM
- Identifier: http://hdl.handle.net/10962/164590 , vital:41146
- Description: Thesis (MSc)--Rhodes University, Faculty of Commerce, Economics and Economic History, 2020
- Full Text:
- Date Issued: 2020
Modification and application of the decentralised wastewater treatment technology for greywater treatment to reduce water needs
- Authors: Ngqwala, Nosiphiwe Patience
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193509 , vital:45338
- Description: Water is a scarce resource that is being acknowledged as a limiting factor to further social- economic growth and development. Demand for freshwater is increasing with corresponding increases in human population, industrial and agricultural activities. Alternative sources, such as greywater and rainwater are often polluted. Though greywater can be used for non-potable purposes, such as irrigation, it still requires some measures of treatment to improve its quality. To improve on greywater quality to facilitate its reuse, decentralised wastewater treatment technologies carry a great potential as complementary and alternative means of wastewater management particularly in peri-urban areas. Five research goals are addressed in this thesis: (i) to monitor the performance of Fly Ash Lime Filter Tower (FLFT) in the treatment of greywater; (ii) to modify the Fly Ash Lime Filter Tower in the treatment of greywater in order to reduce the pH of the greywater, and improved on the reduction of chemical oxygen demand (COD) and coliform counts; (iii) to investigate the potential of the reuse of greywater for irrigation; (iv) to undertake a techno analysis of the FLFT system for commercial use; and (v) to evaluate the use of hydrogen-sulphide (H2S) test kit to monitor faecal contamination of various water sources using a multidisciplinary approach. The modification of the FLFT indicated good treatment efficiency, reducing the concentrations of COD, chlorides, nitrates, ammonia and sulphate by 82.6%, 60.4%, 72.9%, 60.5%, and 53.9%, respectively; while the average pH was at 8.3. Greywater contains nutrients that are beneficial to the growth of most plants. Growth variables included biomass, stem height, number of leaves and number of vegetables harvested. Soil analysis showed no effects of the treated greywater on soil physico-chemical and microbial quality with bulk density 2.0g/cm3, average pH 7.4, total phosphorus 0.16mg/L 8, faecal coliform 0.3 CFU/100 ml. The tomatoes had high biomass and dry weight (150 g; 33g) than beetroot (35 g; 15 g). Crops irrigated with greywater significantly grew faster compared with those irrigated with tap water. The community approach highlighted the value of knowledge management in greywater reuse. It highlighted the importance of creating an institutional knowledge in water management using the H2S kit. The techno-economic analysis was used to evaluate key factors and the activities that are relevant to develop a sustainable FLFT in order to gain insights into the possibility of developing, and incorporating a business model framework to support decision making in value creation and value capturing during the research and the scaling up of the system. By this, a long term perspective to accomplish sustainable FLFT service businesses can be achieved. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
- Full Text:
- Date Issued: 2015
- Authors: Ngqwala, Nosiphiwe Patience
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193509 , vital:45338
- Description: Water is a scarce resource that is being acknowledged as a limiting factor to further social- economic growth and development. Demand for freshwater is increasing with corresponding increases in human population, industrial and agricultural activities. Alternative sources, such as greywater and rainwater are often polluted. Though greywater can be used for non-potable purposes, such as irrigation, it still requires some measures of treatment to improve its quality. To improve on greywater quality to facilitate its reuse, decentralised wastewater treatment technologies carry a great potential as complementary and alternative means of wastewater management particularly in peri-urban areas. Five research goals are addressed in this thesis: (i) to monitor the performance of Fly Ash Lime Filter Tower (FLFT) in the treatment of greywater; (ii) to modify the Fly Ash Lime Filter Tower in the treatment of greywater in order to reduce the pH of the greywater, and improved on the reduction of chemical oxygen demand (COD) and coliform counts; (iii) to investigate the potential of the reuse of greywater for irrigation; (iv) to undertake a techno analysis of the FLFT system for commercial use; and (v) to evaluate the use of hydrogen-sulphide (H2S) test kit to monitor faecal contamination of various water sources using a multidisciplinary approach. The modification of the FLFT indicated good treatment efficiency, reducing the concentrations of COD, chlorides, nitrates, ammonia and sulphate by 82.6%, 60.4%, 72.9%, 60.5%, and 53.9%, respectively; while the average pH was at 8.3. Greywater contains nutrients that are beneficial to the growth of most plants. Growth variables included biomass, stem height, number of leaves and number of vegetables harvested. Soil analysis showed no effects of the treated greywater on soil physico-chemical and microbial quality with bulk density 2.0g/cm3, average pH 7.4, total phosphorus 0.16mg/L 8, faecal coliform 0.3 CFU/100 ml. The tomatoes had high biomass and dry weight (150 g; 33g) than beetroot (35 g; 15 g). Crops irrigated with greywater significantly grew faster compared with those irrigated with tap water. The community approach highlighted the value of knowledge management in greywater reuse. It highlighted the importance of creating an institutional knowledge in water management using the H2S kit. The techno-economic analysis was used to evaluate key factors and the activities that are relevant to develop a sustainable FLFT in order to gain insights into the possibility of developing, and incorporating a business model framework to support decision making in value creation and value capturing during the research and the scaling up of the system. By this, a long term perspective to accomplish sustainable FLFT service businesses can be achieved. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
- Full Text:
- Date Issued: 2015
Orchid mycorrhizal and endophytic fungal diversity of three cooccurring terrestrial orchids in the large African genus Disa (Orchidaceae)
- Authors: Le Du, Bridgitte M
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/163363 , vital:41033
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, English Language and Linguistics, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Le Du, Bridgitte M
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/163363 , vital:41033
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, English Language and Linguistics, 2020.
- Full Text:
- Date Issued: 2020
An analysis of womxn’s understanding of South African public health awareness campaigns’ messages on HIV/AIDS using cognitive interviewing
- Authors: Simpo, Hazel
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408738 , vital:70521
- Description: Besides having the most extensive antiretroviral therapy (ART) treatment programme, South Africa faces the highest epidemic rate, with womxn and children most affected. Several prevention strategies have been implemented to curb the spread of HIV/AIDS in South Africa, including free access to print form awareness campaigns that come through pamphlets, posters and billboards. However, most public health sector awareness and educational programmes carry uniform messages that are then carried out in heterogeneous contexts leading to the miscomprehension of the intended messages. This study aimed to explore womxn’s understanding of public health awareness content on the prevention of HIV/AIDS. The focus was on examining their interpretation of universal HIV/AIDS awareness messages in their heterogeneous contexts, which might provide obstacles to womxn’s reproductive health and well-being using a reproductive justice framework. This study employed a cognitive interviewing methodology to collect data from the participants to obtain information about how participants understand and perceive knowledge and how they arrive at specific answers or judgements. Twenty-eight (28) womxn aged between 18 and 30 years were purposively sampled for this study from four (4) local healthcare facilities in Makhanda: the Grahamstown Municipality (Anglo-African) Clinic, the Joza Clinic, the Settlers Day Hospital and the Raglan Road Clinic. Thematic network analysis (Attride-Stirling, 2001) was used to analyse the data collected from the study. One global theme emerged from the dataset: Barriers to HIV prevention, care and treatment. The barriers were identified mainly due to social constructions of hegemonic masculinity, individual versus cultural expectations, and outdated awareness content. The findings from the study suggest that almost all the challenges that womxn faced in terms of understanding and interpreting the awareness materials stemmed from structural factors in the South African context. The findings also suggest that cognitive interviewing methodology can be reconceptualised as an endeavour that cuts across a wide range of fields. , Thesis (MSocSci) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Simpo, Hazel
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408738 , vital:70521
- Description: Besides having the most extensive antiretroviral therapy (ART) treatment programme, South Africa faces the highest epidemic rate, with womxn and children most affected. Several prevention strategies have been implemented to curb the spread of HIV/AIDS in South Africa, including free access to print form awareness campaigns that come through pamphlets, posters and billboards. However, most public health sector awareness and educational programmes carry uniform messages that are then carried out in heterogeneous contexts leading to the miscomprehension of the intended messages. This study aimed to explore womxn’s understanding of public health awareness content on the prevention of HIV/AIDS. The focus was on examining their interpretation of universal HIV/AIDS awareness messages in their heterogeneous contexts, which might provide obstacles to womxn’s reproductive health and well-being using a reproductive justice framework. This study employed a cognitive interviewing methodology to collect data from the participants to obtain information about how participants understand and perceive knowledge and how they arrive at specific answers or judgements. Twenty-eight (28) womxn aged between 18 and 30 years were purposively sampled for this study from four (4) local healthcare facilities in Makhanda: the Grahamstown Municipality (Anglo-African) Clinic, the Joza Clinic, the Settlers Day Hospital and the Raglan Road Clinic. Thematic network analysis (Attride-Stirling, 2001) was used to analyse the data collected from the study. One global theme emerged from the dataset: Barriers to HIV prevention, care and treatment. The barriers were identified mainly due to social constructions of hegemonic masculinity, individual versus cultural expectations, and outdated awareness content. The findings from the study suggest that almost all the challenges that womxn faced in terms of understanding and interpreting the awareness materials stemmed from structural factors in the South African context. The findings also suggest that cognitive interviewing methodology can be reconceptualised as an endeavour that cuts across a wide range of fields. , Thesis (MSocSci) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
Comparative analysis of the known Hop1b and the novel Hop1a isoforms of the Hop gene
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
The design, synthesis and antiplasmodial activity of a series of halogenated fosmidomycin analogues and hybrid drugs
- Authors: Afolayan, Anthonia Folake
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64370 , vital:28538
- Description: Malaria continues to be a devastating disease and a major cause of death in sub-Saharan Africa. With resistance against most of the available antimalarial drugs, there is a need for ongoing research and development of antimalarial agents. Fosmidomycin and its acetyl analogue FR900098 have been identified as potent inhibitors of Plasmodium falciparum, the causative agent of the most deadly form of malaria. Clinical trials of these agents have revealed poor absorption due to their high hydrophilicity. In the present studies the effect of halogenation of the acyl chain as well as the biological effect of extending the acyl sidechain was explored. This provided the basis on which fosmidomycin hybrids were designed to investigate the feasibility of hybrid extending into NADPH binding pocket. Synthesis of a series of halogenated FR900098 analogues was carried out in three stages. This included i) The introduction of the phosphonate group by reaction with 1,3dibromopropane in an Arbuzov reaction, ii) The introduction of a hydroxamate group by reaction of the propyl phosphonate by means of a nucleophilic substitution reaction with BocNHOBn and iii) The introduction of a halogenated acyl side chain on a protected fosmidomycin backbone. The synthesis of fosmidomycin-hybrids for which chloroquinefosmidomycin hybrids were used as the prototype, involved convergence of the two separately constructed moieties i.e. fosmidomycin and the quinoline moieties in a covalent linkage. The quinoline moiety was easily synthesized from the reaction of 4,7dichloroquinoline with 1,2-diamino ethane. The aminoquinoline so formed resulted in chloroquine-fosmidomycin hybrids 3.8 and 3.9 when reacted with halogenated FR900098 analogues. Antiplasmodial assays were conducted on the chloroquine-fosmidomycin hybrids and the halogenated fosmidomycin derivatives against the chloroquine resistant Gambian FCR-3 strain of P. falciparum. The most potent iodoacetyl fosmidomycin analogues 2.21 gave an IC50 value of 5.54 µM which is eight times more potent than the known antiplasmodial FR900098 which gave an IC50 value of 41.67 µM. All the halogenated FR900098 analogues showed better antiplasmodial activity than their non-halogenated derivatives. This indicated that the presence of halogens in the FR900098 analogues contributes to their biological Chapter 1 Literature review activity. The acetyl and propyl linked hybrids 3.8 and 3.9 showed potent antiplasmodial activity with IC50 values of 0.18 and 0.82 µM respectively. These were by far the most potent hybrids synthesized and provided leads for a new class of promising antimalarial agents. Preliminary E. coli DXR enzyme inhibition assays were carried out on the halogenated fosmidomycin analogues. The results showed good inhibition of the enzyme by the phosphonic acids of the chloroacetyl and chloropropyl analogues 2.1 and 2.2 respectively. Molecular modelling of the compounds on E. coli (PDB code: 2EGH) and P. falciparum (PDB code: 3AUA) DXR showed strong binding of the halogenated fosmidomycin analogues while the hybrids in the absence of docked NADPH showed minimum binding to the enzymes.
- Full Text:
- Date Issued: 2012
- Authors: Afolayan, Anthonia Folake
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64370 , vital:28538
- Description: Malaria continues to be a devastating disease and a major cause of death in sub-Saharan Africa. With resistance against most of the available antimalarial drugs, there is a need for ongoing research and development of antimalarial agents. Fosmidomycin and its acetyl analogue FR900098 have been identified as potent inhibitors of Plasmodium falciparum, the causative agent of the most deadly form of malaria. Clinical trials of these agents have revealed poor absorption due to their high hydrophilicity. In the present studies the effect of halogenation of the acyl chain as well as the biological effect of extending the acyl sidechain was explored. This provided the basis on which fosmidomycin hybrids were designed to investigate the feasibility of hybrid extending into NADPH binding pocket. Synthesis of a series of halogenated FR900098 analogues was carried out in three stages. This included i) The introduction of the phosphonate group by reaction with 1,3dibromopropane in an Arbuzov reaction, ii) The introduction of a hydroxamate group by reaction of the propyl phosphonate by means of a nucleophilic substitution reaction with BocNHOBn and iii) The introduction of a halogenated acyl side chain on a protected fosmidomycin backbone. The synthesis of fosmidomycin-hybrids for which chloroquinefosmidomycin hybrids were used as the prototype, involved convergence of the two separately constructed moieties i.e. fosmidomycin and the quinoline moieties in a covalent linkage. The quinoline moiety was easily synthesized from the reaction of 4,7dichloroquinoline with 1,2-diamino ethane. The aminoquinoline so formed resulted in chloroquine-fosmidomycin hybrids 3.8 and 3.9 when reacted with halogenated FR900098 analogues. Antiplasmodial assays were conducted on the chloroquine-fosmidomycin hybrids and the halogenated fosmidomycin derivatives against the chloroquine resistant Gambian FCR-3 strain of P. falciparum. The most potent iodoacetyl fosmidomycin analogues 2.21 gave an IC50 value of 5.54 µM which is eight times more potent than the known antiplasmodial FR900098 which gave an IC50 value of 41.67 µM. All the halogenated FR900098 analogues showed better antiplasmodial activity than their non-halogenated derivatives. This indicated that the presence of halogens in the FR900098 analogues contributes to their biological Chapter 1 Literature review activity. The acetyl and propyl linked hybrids 3.8 and 3.9 showed potent antiplasmodial activity with IC50 values of 0.18 and 0.82 µM respectively. These were by far the most potent hybrids synthesized and provided leads for a new class of promising antimalarial agents. Preliminary E. coli DXR enzyme inhibition assays were carried out on the halogenated fosmidomycin analogues. The results showed good inhibition of the enzyme by the phosphonic acids of the chloroacetyl and chloropropyl analogues 2.1 and 2.2 respectively. Molecular modelling of the compounds on E. coli (PDB code: 2EGH) and P. falciparum (PDB code: 3AUA) DXR showed strong binding of the halogenated fosmidomycin analogues while the hybrids in the absence of docked NADPH showed minimum binding to the enzymes.
- Full Text:
- Date Issued: 2012
Financial technology and bank risk-taking behavior: a case of selected South African banks
- Authors: Magula, Zizipho
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234206 , vital:50172
- Description: Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Magula, Zizipho
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234206 , vital:50172
- Description: Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
Exploring pre-service teachers’ reflective practice in the context of video-based lesson analysis
- Authors: Chikiwa, Samukeliso
- Date: 2020-04-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/355357 , vital:64492
- Description: This study explored the development of reflective practice in foundation phase pre-service teachers in the context of video-based lesson analysis at a university in South Africa. The study was conducted in the field of mathematics education, responding to the urgent need to equip pre-service South African teachers with the knowledge and skills for effective mathematics teaching. The research is foregrounded by the continuing poor performance of South African learners in mathematics at all levels of education in the country, which has been linked to the inadequate knowledge and skills of mathematics teachers. Pre-service teacher education is putting considerable effort into improving the preparation of mathematics teachers and developing their ability to reflect on their teaching practice is one of the strategies being employed for this purpose. Research has demonstrated the importance of reflective practice (RP) in both developing and extending teachers’ mathematical knowledge for teaching. This study therefore contributes to current research that supports the development of RP as a professional skill for promoting the acquisition of knowledge for teaching in pre-service teacher education. The study adopted a qualitative case study approach with two phases of data collection. In Phase 1 I collected and analysed three sets of 19 pre-service teachers’ written reflections to establish the nature of the reflections that they developed when analysing video-recorded mathematics lessons of experienced teachers’ practice. Phase 2 was conducted with four PSTs who reflected on video-recorded mathematics lessons of their own practice, and similarly sought to investigate the nature of the reflections they developed when reflecting on practice. The four PSTs wrote one set of reflections on their own lessons, went through three sessions of facilitator-guided reflections, then wrote another set of reflections to establish if the support provided in small group facilitator-guided sessions improved their reflections. Iterative content analysis was employed to analyse the PSTs’ written reflections, using an analytic tool that I developed for this purpose through merging Lee’s (2007) and Muir and Beswick’s (2007) levels of reflection frameworks. My model had four levels of reflection: description, explanation, suggestion and reflectivity. The names of each of the levels connect to the key indicator for that level. PSTs’ written reflections were coded and analysed according to these levels. The study found that PSTs’ initial reflections were mostly description of general classroom events with little reflection at the levels of explanation and suggestion, and an absence of reflectivity. Most reflections focused on general events in the lesson rather than mathematical events, even though the six lens framework they were given to guide their reflections prompted them to steer their attention towards mathematical events. The second and third sets of reflections, although mostly still at level 1, showed some shifts towards explanation and suggestion, although an increased focus on mathematical events though reflectivity was still largely absent. No PST reached the fourth level of reflectivity in Phase 1. However, in Phase 2, the PSTs’ reflections after the three small group facilitator-guided sessions included some evidence of reflectivity. The findings suggest the need for pre-service teacher educators to make a concerted effort to teach PSTs what reflection is and how to reflect on their practice. The findings also showed the need for small group facilitator-guided support in the development of PSTs’ reflective practice. , Thesis (PhD) -- Faculty of Education, Education, 2020
- Full Text:
- Date Issued: 2020-04-30
- Authors: Chikiwa, Samukeliso
- Date: 2020-04-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/355357 , vital:64492
- Description: This study explored the development of reflective practice in foundation phase pre-service teachers in the context of video-based lesson analysis at a university in South Africa. The study was conducted in the field of mathematics education, responding to the urgent need to equip pre-service South African teachers with the knowledge and skills for effective mathematics teaching. The research is foregrounded by the continuing poor performance of South African learners in mathematics at all levels of education in the country, which has been linked to the inadequate knowledge and skills of mathematics teachers. Pre-service teacher education is putting considerable effort into improving the preparation of mathematics teachers and developing their ability to reflect on their teaching practice is one of the strategies being employed for this purpose. Research has demonstrated the importance of reflective practice (RP) in both developing and extending teachers’ mathematical knowledge for teaching. This study therefore contributes to current research that supports the development of RP as a professional skill for promoting the acquisition of knowledge for teaching in pre-service teacher education. The study adopted a qualitative case study approach with two phases of data collection. In Phase 1 I collected and analysed three sets of 19 pre-service teachers’ written reflections to establish the nature of the reflections that they developed when analysing video-recorded mathematics lessons of experienced teachers’ practice. Phase 2 was conducted with four PSTs who reflected on video-recorded mathematics lessons of their own practice, and similarly sought to investigate the nature of the reflections they developed when reflecting on practice. The four PSTs wrote one set of reflections on their own lessons, went through three sessions of facilitator-guided reflections, then wrote another set of reflections to establish if the support provided in small group facilitator-guided sessions improved their reflections. Iterative content analysis was employed to analyse the PSTs’ written reflections, using an analytic tool that I developed for this purpose through merging Lee’s (2007) and Muir and Beswick’s (2007) levels of reflection frameworks. My model had four levels of reflection: description, explanation, suggestion and reflectivity. The names of each of the levels connect to the key indicator for that level. PSTs’ written reflections were coded and analysed according to these levels. The study found that PSTs’ initial reflections were mostly description of general classroom events with little reflection at the levels of explanation and suggestion, and an absence of reflectivity. Most reflections focused on general events in the lesson rather than mathematical events, even though the six lens framework they were given to guide their reflections prompted them to steer their attention towards mathematical events. The second and third sets of reflections, although mostly still at level 1, showed some shifts towards explanation and suggestion, although an increased focus on mathematical events though reflectivity was still largely absent. No PST reached the fourth level of reflectivity in Phase 1. However, in Phase 2, the PSTs’ reflections after the three small group facilitator-guided sessions included some evidence of reflectivity. The findings suggest the need for pre-service teacher educators to make a concerted effort to teach PSTs what reflection is and how to reflect on their practice. The findings also showed the need for small group facilitator-guided support in the development of PSTs’ reflective practice. , Thesis (PhD) -- Faculty of Education, Education, 2020
- Full Text:
- Date Issued: 2020-04-30
South African traditional healers’ perceptions and treatment of the symptoms of depression
- Authors: Augustine, Daniella Joan
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408789 , vital:70525
- Description: While depression is experienced worldwide, the World Health Organization indicated that over 80% of this disease burden is found in low- and middle-income countries, with 16% of depressive disorder cases being found in Africa. Specifically, in South Africa, the lifetime prevalence of major depressive disorder is 9.7%. Research conducted on traditional healing estimates that as high as 80% of black individuals in South Africa choose to consult traditional healers. Although there was initial consensus that the use of traditional healers reflected a lack of access to alternative resources, more recent research has however indicated that traditional healers are consulted even when psychiatric facilities and medication are available. Research has illustrated that many patients that chose to consult traditional healers do so as a result of their shared beliefs, and traditional healers' ability to understand the cultural frameworks underlying illness. The current study investigated how traditional healers in the Eastern Cape perceive and treat phenomena currently understood as the symptoms of depression and how these understandings can be incorporated into collaborations between Western medicine and traditional healing practice. A qualitative research design was used to examine the perspectives and treatment methods of isiXhosa traditional healers in the Eastern Cape. Four healers participated in the study. Key findings indicated that there is no single cause or definition of the phenomenon of depression by healers. Causality is greatly attributed to spiritual causes and ancestors play a key role in guiding the diagnosis and multiple treatment interventions employed by healers to treat the experience of depression. Finally, all traditional healers expressed a willingness to collaborate and work with the Western healthcare system, however, they indicated a strong need for greater recognition as a valid healthcare system. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Augustine, Daniella Joan
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408789 , vital:70525
- Description: While depression is experienced worldwide, the World Health Organization indicated that over 80% of this disease burden is found in low- and middle-income countries, with 16% of depressive disorder cases being found in Africa. Specifically, in South Africa, the lifetime prevalence of major depressive disorder is 9.7%. Research conducted on traditional healing estimates that as high as 80% of black individuals in South Africa choose to consult traditional healers. Although there was initial consensus that the use of traditional healers reflected a lack of access to alternative resources, more recent research has however indicated that traditional healers are consulted even when psychiatric facilities and medication are available. Research has illustrated that many patients that chose to consult traditional healers do so as a result of their shared beliefs, and traditional healers' ability to understand the cultural frameworks underlying illness. The current study investigated how traditional healers in the Eastern Cape perceive and treat phenomena currently understood as the symptoms of depression and how these understandings can be incorporated into collaborations between Western medicine and traditional healing practice. A qualitative research design was used to examine the perspectives and treatment methods of isiXhosa traditional healers in the Eastern Cape. Four healers participated in the study. Key findings indicated that there is no single cause or definition of the phenomenon of depression by healers. Causality is greatly attributed to spiritual causes and ancestors play a key role in guiding the diagnosis and multiple treatment interventions employed by healers to treat the experience of depression. Finally, all traditional healers expressed a willingness to collaborate and work with the Western healthcare system, however, they indicated a strong need for greater recognition as a valid healthcare system. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
Islamic compliant short term insurance: an exploratory study to develop an Islamic compliant insurance model within a South African context
- Authors: Jeeva, Shakir
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193633 , vital:45375
- Description: In a world where there is ever increasing risks to be mitigated, either by choice or due to the law of the country, an insurance instrument is the most popular risk mitigation tool. However, from an Islamic perspective, Muslims have certain parameters to adhere to due to the laws and boundaries as set out in the Quraan, as well as the teachings of the final prophet, Prophet Muhammed (Peace Be Upon Him). This has relevance in this context as, according to Islam, the conventional insurance models are in contravention of certain Islamic laws as they contain elements which are not acceptable in the Muslim faith. Therefore, the Islamic insurance models, or Takaful models, have removed the impermissible elements of usury, speculation, and uncertainty, which are all contained in the current conventional insurance models. By removing these impermissible elements from the insurance model, the Takaful model is acceptable for Muslims to use as a risk mitigation tool. The primary aim of the study sought to propose a short term Islamic compliant insurance model within a South African framework. The secondary aims were to ascertain the Islamic requirements for an Islamic insurance model, how these requirements fit into an insurance model, to then compare and contrast the differences between conventional insurance and Islamic insurance and, lastly, to explore awareness and attitudes towards Islamic insurance. Therefore, from the above, a proposed short term Islamic insurance model was developed within a South African context which conforms to the laws and boundaries of Islam, making this insurance model permissible to use as a Takaful tool. Additionally, semi structured interviews were conducted with certain research participants, using purposive sampling, to examine the attitudes and knowledge of the Muslim community towards the Takaful model within a South African context. It was concluded that while the majority of the research participants understand the Takaful model and the significance of this, they have chosen to use the conventional insurance offerings due to the fact that they were unaware of other Takaful alternatives, or due to the fact that the Takaful alternative was out-priced when compared to the conventional insurance offerings. It was therefore concluded that while there is a need for Takaful offerings within South Africa, this must be done in conjunction with additional marketing, education and competitive pricing for potential clients to consider this as an insurance option. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2016
- Full Text:
- Date Issued: 2016
- Authors: Jeeva, Shakir
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193633 , vital:45375
- Description: In a world where there is ever increasing risks to be mitigated, either by choice or due to the law of the country, an insurance instrument is the most popular risk mitigation tool. However, from an Islamic perspective, Muslims have certain parameters to adhere to due to the laws and boundaries as set out in the Quraan, as well as the teachings of the final prophet, Prophet Muhammed (Peace Be Upon Him). This has relevance in this context as, according to Islam, the conventional insurance models are in contravention of certain Islamic laws as they contain elements which are not acceptable in the Muslim faith. Therefore, the Islamic insurance models, or Takaful models, have removed the impermissible elements of usury, speculation, and uncertainty, which are all contained in the current conventional insurance models. By removing these impermissible elements from the insurance model, the Takaful model is acceptable for Muslims to use as a risk mitigation tool. The primary aim of the study sought to propose a short term Islamic compliant insurance model within a South African framework. The secondary aims were to ascertain the Islamic requirements for an Islamic insurance model, how these requirements fit into an insurance model, to then compare and contrast the differences between conventional insurance and Islamic insurance and, lastly, to explore awareness and attitudes towards Islamic insurance. Therefore, from the above, a proposed short term Islamic insurance model was developed within a South African context which conforms to the laws and boundaries of Islam, making this insurance model permissible to use as a Takaful tool. Additionally, semi structured interviews were conducted with certain research participants, using purposive sampling, to examine the attitudes and knowledge of the Muslim community towards the Takaful model within a South African context. It was concluded that while the majority of the research participants understand the Takaful model and the significance of this, they have chosen to use the conventional insurance offerings due to the fact that they were unaware of other Takaful alternatives, or due to the fact that the Takaful alternative was out-priced when compared to the conventional insurance offerings. It was therefore concluded that while there is a need for Takaful offerings within South Africa, this must be done in conjunction with additional marketing, education and competitive pricing for potential clients to consider this as an insurance option. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2016
- Full Text:
- Date Issued: 2016
Philosophical inquiry into the value of liberal education
- Authors: Wotshela, Siphosihle
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408954 , vital:70540
- Description: Throughout history, scholars have offered numerous conceptions of liberal education, with each scholar providing a slightly and sometimes extremely different idea of what liberal education actually is, what it entails, and what value one stands to gain by partaking in this particular type of education. In this thesis, I inquire into the topic of liberal education in an attempt to clearly understand what value partaking in this type of education offers the contemporary South African. In the process, I offer a defence against what I refer to as the societal context problem—a problem that questions the possibility of a universal benefit that can be obtained by partaking in liberal education. I also offer a comprehensive argument for the preference of Jacob Klein’s conception of liberal education, making the claim that Klein’s conception and the value he identifies with his conception is more convincing than that offered by other scholars because Klein’s conception and the value associated with the conception is universal in a way that allows it to remain relevant even when confronted with the problem of societal context. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Wotshela, Siphosihle
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408954 , vital:70540
- Description: Throughout history, scholars have offered numerous conceptions of liberal education, with each scholar providing a slightly and sometimes extremely different idea of what liberal education actually is, what it entails, and what value one stands to gain by partaking in this particular type of education. In this thesis, I inquire into the topic of liberal education in an attempt to clearly understand what value partaking in this type of education offers the contemporary South African. In the process, I offer a defence against what I refer to as the societal context problem—a problem that questions the possibility of a universal benefit that can be obtained by partaking in liberal education. I also offer a comprehensive argument for the preference of Jacob Klein’s conception of liberal education, making the claim that Klein’s conception and the value he identifies with his conception is more convincing than that offered by other scholars because Klein’s conception and the value associated with the conception is universal in a way that allows it to remain relevant even when confronted with the problem of societal context. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
- Date Issued: 2023-03-30
Bioinformatic analysis of Aminoacyl tRNA Synthetases as potential antimalarial drug targets
- Authors: Nyamai, Dorothy Wavinya
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164579 , vital:41142 , doi:10.21504/10962/164579
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Nyamai, Dorothy Wavinya
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164579 , vital:41142 , doi:10.21504/10962/164579
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Country risk and stock market volatility in Africa: Measuring the contribution of political and economic risk factors
- Authors: Hoveni, Jamela Basani
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405445 , vital:70172
- Description: Thesis embargoed. To be released in 2025. , Thesis (PhD) -- Faculty of Commerce, Economics and economic History, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Hoveni, Jamela Basani
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405445 , vital:70172
- Description: Thesis embargoed. To be released in 2025. , Thesis (PhD) -- Faculty of Commerce, Economics and economic History, 2022
- Full Text:
- Date Issued: 2022-10-14
Shifting Norms and Practices of International Criminal Justice: Exploring African State and Non-State Agency at the International Criminal Court
- Authors: Mtero, Shingirai
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192875 , vital:45273
- Description: Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mtero, Shingirai
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192875 , vital:45273
- Description: Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Tectonic and structural aspects at the Otjihase Mine, Matchless Belt, Namibia: A Systematic Review
- Authors: Hartmann, K
- Date: 1995-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190232 , vital:44976
- Description: The Otjihase pyritic massive sulphide deposit occurs within a 10km thick metasedimentary sequence of the Kuiseb Formation. The Kuiseb metasediments were deposited within the Khomas Trough, which forms the southernmost rift of the intracontinental arm of the Damara orogen. Amphibolite units of the Matchless member at Otjihase have a MORB-type geochemical character and occur within the Kuiseb schists, about 200m above the ore zone. The Otjihase mine is the largest of many Besshi-type deposits that occur in close proximity to the Matchless amphibolites. A depositional environment in a rift, slightly more advanced than the present-day Red Sea is envisaged. The five parallel, ruler-shaped, mineralised shoots at Otjihase occur on the same stratigraphic level. They have a plunge of approximately 6° to the west and a dip of approximately 16° to the northwest. The largest and best mineralised, is the northernmost shoot (the Main Shoot) which is ±250m wide, up to 12m thick and has a known length of 7,5km. The large length/breadth ratio is ascribed to the original setting along faults and thickening of the ore zone during thrusting. Intense ductile deformation has affected the ore bodies, with isoclinal refolding, boudinaging, duplexes of more competent bands and smearing of the schists. Squeezing and remobilisation of the sulphides into the schistosity and low pressure pods has taken place. Successive folding and thrusting during the D2 deformational event resulted in the dominant structural style. Fold axes of drag folds plot onto a great circle in stereographic projection, indicating the formation of sheath folds. The axial planar cleavages of competent layers is steeper than the S(0,1) foliation and suggests a structural right way-up. The presence of chloritic alteration above the ore shoots, is suggestive of footwall alteration indicating that the sequence was overturned during the D1 deformational event. Ore zone lithologies include stringery-, massive- and semi-massive sulphides, mineralised magnetite- quartzites and disseminated sulphide mineralisation within quartz-biotite-chlorite schists. Chalcopyrite is the main economic mineral and mainly occurs as matrix to pyrite and in coarse-grained pods. Lithological and metal zoning within the Main Shoot is distinct and is an indication that the macroscopic shape of the orebody is largely unaffected by later ductile deformation. North-south trending normal faults of the Windhoek Graben have disrupted the continuity of the ore shoots. In section, the faults appear to have a listric shape. The major faults have pronounced scissor movements and as a result the dips of the blocks within fault zones are affected. , Thesis (MSc) -- Faculty of Science, Exploration Geology, 2021
- Full Text:
- Date Issued: 1995-04
- Authors: Hartmann, K
- Date: 1995-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190232 , vital:44976
- Description: The Otjihase pyritic massive sulphide deposit occurs within a 10km thick metasedimentary sequence of the Kuiseb Formation. The Kuiseb metasediments were deposited within the Khomas Trough, which forms the southernmost rift of the intracontinental arm of the Damara orogen. Amphibolite units of the Matchless member at Otjihase have a MORB-type geochemical character and occur within the Kuiseb schists, about 200m above the ore zone. The Otjihase mine is the largest of many Besshi-type deposits that occur in close proximity to the Matchless amphibolites. A depositional environment in a rift, slightly more advanced than the present-day Red Sea is envisaged. The five parallel, ruler-shaped, mineralised shoots at Otjihase occur on the same stratigraphic level. They have a plunge of approximately 6° to the west and a dip of approximately 16° to the northwest. The largest and best mineralised, is the northernmost shoot (the Main Shoot) which is ±250m wide, up to 12m thick and has a known length of 7,5km. The large length/breadth ratio is ascribed to the original setting along faults and thickening of the ore zone during thrusting. Intense ductile deformation has affected the ore bodies, with isoclinal refolding, boudinaging, duplexes of more competent bands and smearing of the schists. Squeezing and remobilisation of the sulphides into the schistosity and low pressure pods has taken place. Successive folding and thrusting during the D2 deformational event resulted in the dominant structural style. Fold axes of drag folds plot onto a great circle in stereographic projection, indicating the formation of sheath folds. The axial planar cleavages of competent layers is steeper than the S(0,1) foliation and suggests a structural right way-up. The presence of chloritic alteration above the ore shoots, is suggestive of footwall alteration indicating that the sequence was overturned during the D1 deformational event. Ore zone lithologies include stringery-, massive- and semi-massive sulphides, mineralised magnetite- quartzites and disseminated sulphide mineralisation within quartz-biotite-chlorite schists. Chalcopyrite is the main economic mineral and mainly occurs as matrix to pyrite and in coarse-grained pods. Lithological and metal zoning within the Main Shoot is distinct and is an indication that the macroscopic shape of the orebody is largely unaffected by later ductile deformation. North-south trending normal faults of the Windhoek Graben have disrupted the continuity of the ore shoots. In section, the faults appear to have a listric shape. The major faults have pronounced scissor movements and as a result the dips of the blocks within fault zones are affected. , Thesis (MSc) -- Faculty of Science, Exploration Geology, 2021
- Full Text:
- Date Issued: 1995-04
Behaviour and trophic ecology of oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) associated with floating objects in the open ocean
- Forget, Fabien Rocky Gilbert
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
Examining the expenditures and retention of money of recreational fishing along the Wild Coast, South Africa
- Authors: Pyle, Michael Jonathan
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419673 , vital:71665
- Description: Developing countries and rural communities rely heavily on the ocean for food, transport, and the sustainability of their livelihoods. While the economics of small-scale fisheries in rural areas have received much attention, there is generally less information on the economic contributions from recreational fisheries in these areas. South Africa’s marine recreational fishery is large and contributes to a significant amount of economic activity. However, the retention of money from recreational fishing activities in local rural economies is unknown and thus the potential developmental benefits from this sector remain unquantified. This study examined the economic contributions from recreational fishing along the Wild Coast and retention of expenditures within the local economy. A total of 109 face-to-face economic surveys were administered during the peak recreational fishing season in December 2021. Based on the results, recreational fishing in the Wild Coast has the ability to generate R 415 446 098 in economic activity annually, however only 9.5% of this is retained within local coastal economies, which diminishes the economic contributions of the fishery to the Wild Coast region. Expenditures on items stemming from the informal collection and selling of bait and seafood, domestic work and guiding were the highest locally retained expenditures within the region. 98% of all bait and seafood was harvested and sold by local gillies, with 2% being bought through hotels (n=109). The total direct economic contribution in terms of informal harvesting was estimated at R 16 077 711 for 2021 (n= 9 601). The identification of these contributions can be used to provide recommendations for local economic development strategies which can support the recreational fishery while uplifting coastal communities that should be benefitting more from the activity. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Pyle, Michael Jonathan
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419673 , vital:71665
- Description: Developing countries and rural communities rely heavily on the ocean for food, transport, and the sustainability of their livelihoods. While the economics of small-scale fisheries in rural areas have received much attention, there is generally less information on the economic contributions from recreational fisheries in these areas. South Africa’s marine recreational fishery is large and contributes to a significant amount of economic activity. However, the retention of money from recreational fishing activities in local rural economies is unknown and thus the potential developmental benefits from this sector remain unquantified. This study examined the economic contributions from recreational fishing along the Wild Coast and retention of expenditures within the local economy. A total of 109 face-to-face economic surveys were administered during the peak recreational fishing season in December 2021. Based on the results, recreational fishing in the Wild Coast has the ability to generate R 415 446 098 in economic activity annually, however only 9.5% of this is retained within local coastal economies, which diminishes the economic contributions of the fishery to the Wild Coast region. Expenditures on items stemming from the informal collection and selling of bait and seafood, domestic work and guiding were the highest locally retained expenditures within the region. 98% of all bait and seafood was harvested and sold by local gillies, with 2% being bought through hotels (n=109). The total direct economic contribution in terms of informal harvesting was estimated at R 16 077 711 for 2021 (n= 9 601). The identification of these contributions can be used to provide recommendations for local economic development strategies which can support the recreational fishery while uplifting coastal communities that should be benefitting more from the activity. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2023
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- Date Issued: 2023-10-13