Aging, sex, death (and heavy metals)
- Authors: Limson, Janice L
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:589 , http://hdl.handle.net/10962/d1019732
- Description: Vice Chancellor's Distinguished Research Award Lecture August 2011
- Full Text:
- Date Issued: 2011
- Authors: Limson, Janice L
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:589 , http://hdl.handle.net/10962/d1019732
- Description: Vice Chancellor's Distinguished Research Award Lecture August 2011
- Full Text:
- Date Issued: 2011
The genetic integrity of Labeo capensis and L. umbratus (Cyprinidae) in South Africa in relation to inter-basin water transfer schemes
- Authors: Ramoejane, Mpho
- Date: 2011
- Subjects: Cyprinidae -- South Africa -- Darlington Dam , Cyprinidae -- Namibia -- Hardap Dam , Labeo -- South Africa -- Darlington Dam , Labeo -- Namibia -- Hardap Dam , Fishes -- Hybridisation -- South Africa -- Darlington Dam , Fishes -- Hybridisation -- Namibia -- Hardap Dam , Fishes -- Anatomy -- South Africa -- Darlington Dam , Fishes -- Anatomy -- Namibia -- Hardap Dam , Water transfer -- South Africa-- Darlington Dam , Water transfer -- Namibia -- Hardap Dam
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5367 , http://hdl.handle.net/10962/d1013049
- Description: The Orange-Fish and Cookhouse tunnels that are part of a major inter-basin water transfer scheme (IBT) act as a pathway for several fish species from the Orange River system to enter the Great Fish and Sundays River systems in South Africa. These include Labeo capensis and L. umbratus. Labeo capensis was restricted to the Orange River system before the inter-basin water transfer scheme. Labeo umbratus occurred naturally in the Orange River and in southern flowing river systems. Previous studies showed that the two species hybridise in Hardap Dam, located in a tributary of the Orange River system in Namibia. There are also unconfirmed reports of hybrids from Darlington Dam on the Sundays River system. The aim of the thesis was to confirm hybridisation in Hardap Dam, assess whether hybridisation between L. capensis and L. umbratus has occurred in Darlington Dam and to gain a better understanding of the diversity of these two species. Morphology (morphometrics and meristics), a nuclear S7 intron and the mitochondrial cytochrome ♭ gene were used to assess for hybridisation. A total of 275 specimens were analysed from across the geographical range of the two species. The two species could be distinguished using morphometrics (dorsal fin base, interorbital width and operculum to eye distance) and meristics (lateral line, origin of the dorsal fin to lateral line, origin of the pelvic fin to lateral line and caudal peduncle scale counts) characters. Hybrids from Hardap and Darlington dams were placed between the two species clusters. Labeo umbratus from the Orange River and southern flowing rivers formed a single cluster. The two species could also be distinguished from each other with six nuclear DNA mutations and hybrids were heterozygous at such sites in both dams. Labeo umbratus populations from the Orange River and southern flowing rivers (Gouritz, Gamtoos, Sundays, Bushmans, Great Fish and Nahoon) formed a single lineage. Analysis of mitochondrial DNA, however, revealed that L. umbratus populations from the Orange River and southern flowing rivers were two lineages that differ from each other by 5 mutations. Labeo capensis could be differentiated from both these lineages. Being maternally inherited, mitochondrial DNA did not reveal hybridisation, but ten specimens with L. capensis haplotypes were found in the Darlington Dam. In Hardap Dam, however, it appears that only L. capensis mitochondrial DNA haplotypes persist, despite morphological and nuclear DNA analysis suggesting that both morphs and hybrids of the two species occur. The genetic integrity of these Labeo species has therefore been compromised in at least Hardap and Darlington dams. The Great Fish and Sundays populations are considered to be under threat of complete introgression. The Kat River and Slagboom Dam populations that were isolated before the IBTs have to remain isolated to protect the genetic integrity of the southern lineage of L. umbratus in these two systems.
- Full Text:
- Date Issued: 2011
- Authors: Ramoejane, Mpho
- Date: 2011
- Subjects: Cyprinidae -- South Africa -- Darlington Dam , Cyprinidae -- Namibia -- Hardap Dam , Labeo -- South Africa -- Darlington Dam , Labeo -- Namibia -- Hardap Dam , Fishes -- Hybridisation -- South Africa -- Darlington Dam , Fishes -- Hybridisation -- Namibia -- Hardap Dam , Fishes -- Anatomy -- South Africa -- Darlington Dam , Fishes -- Anatomy -- Namibia -- Hardap Dam , Water transfer -- South Africa-- Darlington Dam , Water transfer -- Namibia -- Hardap Dam
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5367 , http://hdl.handle.net/10962/d1013049
- Description: The Orange-Fish and Cookhouse tunnels that are part of a major inter-basin water transfer scheme (IBT) act as a pathway for several fish species from the Orange River system to enter the Great Fish and Sundays River systems in South Africa. These include Labeo capensis and L. umbratus. Labeo capensis was restricted to the Orange River system before the inter-basin water transfer scheme. Labeo umbratus occurred naturally in the Orange River and in southern flowing river systems. Previous studies showed that the two species hybridise in Hardap Dam, located in a tributary of the Orange River system in Namibia. There are also unconfirmed reports of hybrids from Darlington Dam on the Sundays River system. The aim of the thesis was to confirm hybridisation in Hardap Dam, assess whether hybridisation between L. capensis and L. umbratus has occurred in Darlington Dam and to gain a better understanding of the diversity of these two species. Morphology (morphometrics and meristics), a nuclear S7 intron and the mitochondrial cytochrome ♭ gene were used to assess for hybridisation. A total of 275 specimens were analysed from across the geographical range of the two species. The two species could be distinguished using morphometrics (dorsal fin base, interorbital width and operculum to eye distance) and meristics (lateral line, origin of the dorsal fin to lateral line, origin of the pelvic fin to lateral line and caudal peduncle scale counts) characters. Hybrids from Hardap and Darlington dams were placed between the two species clusters. Labeo umbratus from the Orange River and southern flowing rivers formed a single cluster. The two species could also be distinguished from each other with six nuclear DNA mutations and hybrids were heterozygous at such sites in both dams. Labeo umbratus populations from the Orange River and southern flowing rivers (Gouritz, Gamtoos, Sundays, Bushmans, Great Fish and Nahoon) formed a single lineage. Analysis of mitochondrial DNA, however, revealed that L. umbratus populations from the Orange River and southern flowing rivers were two lineages that differ from each other by 5 mutations. Labeo capensis could be differentiated from both these lineages. Being maternally inherited, mitochondrial DNA did not reveal hybridisation, but ten specimens with L. capensis haplotypes were found in the Darlington Dam. In Hardap Dam, however, it appears that only L. capensis mitochondrial DNA haplotypes persist, despite morphological and nuclear DNA analysis suggesting that both morphs and hybrids of the two species occur. The genetic integrity of these Labeo species has therefore been compromised in at least Hardap and Darlington dams. The Great Fish and Sundays populations are considered to be under threat of complete introgression. The Kat River and Slagboom Dam populations that were isolated before the IBTs have to remain isolated to protect the genetic integrity of the southern lineage of L. umbratus in these two systems.
- Full Text:
- Date Issued: 2011
South African money market volatility, asymmetry and retail interest pass-through
- Authors: Fadiran, Gideon Oluwatobi
- Date: 2011
- Subjects: Money market -- South Africa Interest rates -- South Africa Monetary policy -- South Africa Econometric models Banks and banking -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:993 , http://hdl.handle.net/10962/d1002728
- Description: The purpose of this paper is to examine the interest rate transmission mechanism for South Africa as an emerging economy in a pre-repo and repo system. It explains how the money market rate is transmitted to the retail interest rates both in the long-run and short-run and tests the symmetric and asymmetric interest rate pass-through using the Scholnick (1996) ECM and the Wang and Lee (2009) ECM-EGARCH (1, 1)-M methodology. This permitted the examination of the impact of interest rate volatility, along with the leverage effect. An incomplete pass-through is found in the short-run. From the entire sample period, a symmetric adjustment is found in the deposit rate, which had upward rigidity adjustment, while an asymmetric adjustment is found in the lending rate, with a downward rigidity adjustment. All the adjustments supported the collusive pricing arrangements. According to the conditional variance estimation of the ECM-EGARCH (1, 1), negative volatility impact and leverage effect are present and influential only in the deposit interest rate adjustment process in South Africa.
- Full Text:
- Date Issued: 2011
- Authors: Fadiran, Gideon Oluwatobi
- Date: 2011
- Subjects: Money market -- South Africa Interest rates -- South Africa Monetary policy -- South Africa Econometric models Banks and banking -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:993 , http://hdl.handle.net/10962/d1002728
- Description: The purpose of this paper is to examine the interest rate transmission mechanism for South Africa as an emerging economy in a pre-repo and repo system. It explains how the money market rate is transmitted to the retail interest rates both in the long-run and short-run and tests the symmetric and asymmetric interest rate pass-through using the Scholnick (1996) ECM and the Wang and Lee (2009) ECM-EGARCH (1, 1)-M methodology. This permitted the examination of the impact of interest rate volatility, along with the leverage effect. An incomplete pass-through is found in the short-run. From the entire sample period, a symmetric adjustment is found in the deposit rate, which had upward rigidity adjustment, while an asymmetric adjustment is found in the lending rate, with a downward rigidity adjustment. All the adjustments supported the collusive pricing arrangements. According to the conditional variance estimation of the ECM-EGARCH (1, 1), negative volatility impact and leverage effect are present and influential only in the deposit interest rate adjustment process in South Africa.
- Full Text:
- Date Issued: 2011
Fundamental investigations into the factors affecting the response of laccase-based electrochemical biosensors
- Authors: Fogel, Ronen
- Date: 2011
- Subjects: Laccase Phenols Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4073 , http://hdl.handle.net/10962/d1007166
- Description: Given their widespread effects and distribution in both natural and industrial environments, the monitoring of phenolic compounds is of considerable analytical interest. Electrochemical biosensor technologies, in particular those comprising laccase enzymes, afford many potential benefits to address this analytical need. However, several key factors affecting sensor response currently limit their applicability. This Thesis reports on the fabrication and optimisation of an electrochemical laccase-based biosensor towards the application of the monitoring of phenolic compounds. Selected factors considered to affect sensor response were investigated using the optimised biosensor. These included: electrochemical, biochemical and substrate-dependent factors, which were found to intersect in modulating biosensor response signals. Through the application of transducer-dependent and substrate-dependent parameters, the selective and simultaneous detection of a mixture of different phenolic analytes is successfully demonstrated. This Thesis also investigates the use of Quartz-Crystal Microbalance with Dissipation (QCM-D) technology, an analytical technique that measures physical parameters of thin-film structures, towards the successful monitoring of enzyme immobilisation strategies. These strategies are fundamental to the successful fabrication of biosensors, and the real-time monitoring of immobilised film formations is of considerable research interest. In the studies reported on in this Thesis, QCM-D technology was demonstrated to be an effective complementary technology in the prediction of film immobilisation techniques on the resultant biochemical kinetics of immobilised enzymes.
- Full Text:
- Date Issued: 2011
- Authors: Fogel, Ronen
- Date: 2011
- Subjects: Laccase Phenols Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4073 , http://hdl.handle.net/10962/d1007166
- Description: Given their widespread effects and distribution in both natural and industrial environments, the monitoring of phenolic compounds is of considerable analytical interest. Electrochemical biosensor technologies, in particular those comprising laccase enzymes, afford many potential benefits to address this analytical need. However, several key factors affecting sensor response currently limit their applicability. This Thesis reports on the fabrication and optimisation of an electrochemical laccase-based biosensor towards the application of the monitoring of phenolic compounds. Selected factors considered to affect sensor response were investigated using the optimised biosensor. These included: electrochemical, biochemical and substrate-dependent factors, which were found to intersect in modulating biosensor response signals. Through the application of transducer-dependent and substrate-dependent parameters, the selective and simultaneous detection of a mixture of different phenolic analytes is successfully demonstrated. This Thesis also investigates the use of Quartz-Crystal Microbalance with Dissipation (QCM-D) technology, an analytical technique that measures physical parameters of thin-film structures, towards the successful monitoring of enzyme immobilisation strategies. These strategies are fundamental to the successful fabrication of biosensors, and the real-time monitoring of immobilised film formations is of considerable research interest. In the studies reported on in this Thesis, QCM-D technology was demonstrated to be an effective complementary technology in the prediction of film immobilisation techniques on the resultant biochemical kinetics of immobilised enzymes.
- Full Text:
- Date Issued: 2011
An investigation into knowledge and change in a Grade 9 environmental research project
- Authors: Webber, Susan Marion
- Date: 2011
- Subjects: Environmental education -- Activity programs -- South Africa Environmental education -- Evaluation -- South Africa Environmental education -- Study and teaching (Secondary) -- South Africa Sustainable development -- Evaluation -- South Africa Sustainable development -- Study and teaching (Secondary) -- South Africa Active learning -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1597 , http://hdl.handle.net/10962/d1003479
- Description: This study considers a Grade 9 Integrated Environmental Research Project which was implemented as a vehicle to induce knowledge-based change in learners. It was noted that change did not occur as hoped, and this study was undertaken to review the Grade 9 Project in order to improve it and to probe the apparent gap between knowledge and action. The study generated evidence on the learning processes within the project. This revealed a number of contradictions and tensions which limit change initiatives within the local environment. Notable here was a contradictory mandate between undertaking a research-based change project and responding to the rubric of assessment which was not linked to the research done. It was found that faced with this dual mandate, learners chose to focus on the assessment-laden mandate as this was the ultimate agenda that would reap the reward within the traditional school environment. The study examines the gap between knowledge and practice to probe ways in which to close this gap in the context of an environmental research assignment. The outcome is a recommendation that we as the project designers review the evidence of tensions and contradictions revealed in the study to reflect on the underlying purpose of the project and reshape it in light of recent literature on the challenges of social learning and change.
- Full Text:
- Date Issued: 2011
- Authors: Webber, Susan Marion
- Date: 2011
- Subjects: Environmental education -- Activity programs -- South Africa Environmental education -- Evaluation -- South Africa Environmental education -- Study and teaching (Secondary) -- South Africa Sustainable development -- Evaluation -- South Africa Sustainable development -- Study and teaching (Secondary) -- South Africa Active learning -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1597 , http://hdl.handle.net/10962/d1003479
- Description: This study considers a Grade 9 Integrated Environmental Research Project which was implemented as a vehicle to induce knowledge-based change in learners. It was noted that change did not occur as hoped, and this study was undertaken to review the Grade 9 Project in order to improve it and to probe the apparent gap between knowledge and action. The study generated evidence on the learning processes within the project. This revealed a number of contradictions and tensions which limit change initiatives within the local environment. Notable here was a contradictory mandate between undertaking a research-based change project and responding to the rubric of assessment which was not linked to the research done. It was found that faced with this dual mandate, learners chose to focus on the assessment-laden mandate as this was the ultimate agenda that would reap the reward within the traditional school environment. The study examines the gap between knowledge and practice to probe ways in which to close this gap in the context of an environmental research assignment. The outcome is a recommendation that we as the project designers review the evidence of tensions and contradictions revealed in the study to reflect on the underlying purpose of the project and reshape it in light of recent literature on the challenges of social learning and change.
- Full Text:
- Date Issued: 2011
The impact of forest degradation on carbon stocks of forests in the Matiwane area of the Transkei, South Africa
- Authors: Mangwale, Kagiso
- Date: 2011
- Subjects: Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4781 , http://hdl.handle.net/10962/d1012799 , Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Description: This study focused on assessing the condition and creating a carbon inventory of forests in the Matiwane area of the Transkei. This entailed the use of aerial photography in tracing forest cover change from 1942 to 2007 coupled with ground-truthing to assess whether the forests have in any way endured degradation over the years with a potential reduction in carbon stocks as a result. This study revealed both the loss and gain of biomass in the area with a general trend of forests being continuously converted to agricultural fields resulting in reduced forest area, stem density, tree density and carbon loss in different pools of the forests, reflecting that these forests are degraded. The conversion has resulted in the reduction in the number of species from a mean of 11±0.57 species/200m² in intact forests to 1±0.23species/200m² plot in degraded forests. It was also revealed that approximately 5.2 % (791 hectares) of 15 352 hectares of forest area was lost as a result of the conversion of forest land to agricultural fields from 1942 to 2007 with 99 % of the clearing occurring in the last 33 years (1974-2007) and of which 60 % ( 4 77 hectares) occurred from 1995 to 2007, indicating that forest degradation in these forests is on the increase. The assessment also revealed some areas that were nonforest in 1942 that have accumulated woody biomass (BAA), composed mainly of Acacia sp accounting for 51.18 MgC.ha⁻¹ (Megagrams of carbon per hectare) and total carbon stocks of 0.02 TgC (Teragrams of carbon). The degradation of these forests induced a reduction in carbon stocks from 311.68±23.69 MgC.ha⁻¹ (to a soil depth 0-50 cm) in intact forest to 73.46±12.34 MgC.ha⁻¹ in degraded forests. The total carbon stocks in the degraded forests were approximated at 0.06 TgC and the BAA areas 0.02 TgC with 4.7 TgC in intact forests. The degradation of these forests has resulted in the net carbon loss of 0.19 TgC between 1942 and 2007 but 4.76 TgC is still locked in these forests. The large difference in carbon stocks between intact and degraded forests indicated the need to reduce the degradation of these forests to prevent further carbon loss and reduction of the carbon sequestration potential of these forests.
- Full Text:
- Date Issued: 2011
- Authors: Mangwale, Kagiso
- Date: 2011
- Subjects: Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4781 , http://hdl.handle.net/10962/d1012799 , Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Description: This study focused on assessing the condition and creating a carbon inventory of forests in the Matiwane area of the Transkei. This entailed the use of aerial photography in tracing forest cover change from 1942 to 2007 coupled with ground-truthing to assess whether the forests have in any way endured degradation over the years with a potential reduction in carbon stocks as a result. This study revealed both the loss and gain of biomass in the area with a general trend of forests being continuously converted to agricultural fields resulting in reduced forest area, stem density, tree density and carbon loss in different pools of the forests, reflecting that these forests are degraded. The conversion has resulted in the reduction in the number of species from a mean of 11±0.57 species/200m² in intact forests to 1±0.23species/200m² plot in degraded forests. It was also revealed that approximately 5.2 % (791 hectares) of 15 352 hectares of forest area was lost as a result of the conversion of forest land to agricultural fields from 1942 to 2007 with 99 % of the clearing occurring in the last 33 years (1974-2007) and of which 60 % ( 4 77 hectares) occurred from 1995 to 2007, indicating that forest degradation in these forests is on the increase. The assessment also revealed some areas that were nonforest in 1942 that have accumulated woody biomass (BAA), composed mainly of Acacia sp accounting for 51.18 MgC.ha⁻¹ (Megagrams of carbon per hectare) and total carbon stocks of 0.02 TgC (Teragrams of carbon). The degradation of these forests induced a reduction in carbon stocks from 311.68±23.69 MgC.ha⁻¹ (to a soil depth 0-50 cm) in intact forest to 73.46±12.34 MgC.ha⁻¹ in degraded forests. The total carbon stocks in the degraded forests were approximated at 0.06 TgC and the BAA areas 0.02 TgC with 4.7 TgC in intact forests. The degradation of these forests has resulted in the net carbon loss of 0.19 TgC between 1942 and 2007 but 4.76 TgC is still locked in these forests. The large difference in carbon stocks between intact and degraded forests indicated the need to reduce the degradation of these forests to prevent further carbon loss and reduction of the carbon sequestration potential of these forests.
- Full Text:
- Date Issued: 2011
Studies in marine quinone chemistry
- Authors: Sunassee, Suthananda Naidu
- Date: 2011
- Subjects: Quinone Marine natural products Marine invertebrates Marine pharmacology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4355 , http://hdl.handle.net/10962/d1005020
- Description: This thesis is divided into two parts and the rationale of the research conducted is based on the cytotoxicity of the prenylated quinones 1.24-1.29, isolated from the South African nudibranch Leminda millecra, against oesophageal cancer cells. The first part (Chapters 2 and 3) of the thesis initially documents the distribution of cytotoxic and antioxidant prenylated quinones and hydroquinones in the marine environment. We have been able to show, for the first time, that these compounds can be divided into eight structural classes closely related to their phyletic distribution. Secondly, we attempted to synthesize the two marine natural products 1.24 and 1.26 in an effort to contribute to an ongoing collaborative search with the Division of Medical Biochemistry at the University of Cape Town for new compounds with anti-oesophageal cancer activity. Accordingly, we followed the published synthetic procedure for 1.26 and, although we were unable to reproduce the reported results, we have generated five new prenylated quinone analogues 3.53-3.55, 3.63 and 3.71, which are a potentially viable addition to our ongoing structure-activity relationship (SAR) studies. Moreover, we embarked on a 7Li NMR mechanistic study for the synthesis of 3.2 from 3.1 which rewarded us with an improved and reproducible methodology for this crucial reaction that is detailed in Chapter 3. The second part of this thesis (Chapters 4 and 5) is concerned with a synthetic, structural, electrochemical and biological exploration of the 1,4-naphthoquinone nucleus as a primary pharmacophore in our search for new chemical entities which can induce apoptosis in oesophageal cancer cells, thus contributing to our overall ongoing SAR study in this class of compounds. Seven new naphthoquinone derivatves (4.19, 4.30, 4.31, 4.33 and 4.46-4.48) of the natural products 2-deoxylapachol (2.44), lapachol (4.1) and β-lapachone (5.2) were synthesized and 2-(1`-hydroxy-`-phenylmethyl)-1,4-naphthoquinone (4.29) was found to be the most cytotoxic (IC50 1.5 μM) against the oesophageal cancer cell line WHCO1, while 5.2, which is currently in phase II clinical trials as an anticancer drug, was found to be similarly active (IC50 1.6 μM). Electrochemical investigations of the redox properties of the benzylic alcohol derivatives 4.29-4.31 indicated a higher reduction potential compared to their oxidized counterparts 4.45-4.48, and this finding has been correlated to the increased activity of 4.29-4.31 against the WHCO1 cell line. Additionally, 4.29 is synthetically more accessible than either 1.26 or 5.2 and potentially a lead compound in our search for new and more effective chemotherapeutic agents against oesophageal cancer
- Full Text:
- Date Issued: 2011
- Authors: Sunassee, Suthananda Naidu
- Date: 2011
- Subjects: Quinone Marine natural products Marine invertebrates Marine pharmacology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4355 , http://hdl.handle.net/10962/d1005020
- Description: This thesis is divided into two parts and the rationale of the research conducted is based on the cytotoxicity of the prenylated quinones 1.24-1.29, isolated from the South African nudibranch Leminda millecra, against oesophageal cancer cells. The first part (Chapters 2 and 3) of the thesis initially documents the distribution of cytotoxic and antioxidant prenylated quinones and hydroquinones in the marine environment. We have been able to show, for the first time, that these compounds can be divided into eight structural classes closely related to their phyletic distribution. Secondly, we attempted to synthesize the two marine natural products 1.24 and 1.26 in an effort to contribute to an ongoing collaborative search with the Division of Medical Biochemistry at the University of Cape Town for new compounds with anti-oesophageal cancer activity. Accordingly, we followed the published synthetic procedure for 1.26 and, although we were unable to reproduce the reported results, we have generated five new prenylated quinone analogues 3.53-3.55, 3.63 and 3.71, which are a potentially viable addition to our ongoing structure-activity relationship (SAR) studies. Moreover, we embarked on a 7Li NMR mechanistic study for the synthesis of 3.2 from 3.1 which rewarded us with an improved and reproducible methodology for this crucial reaction that is detailed in Chapter 3. The second part of this thesis (Chapters 4 and 5) is concerned with a synthetic, structural, electrochemical and biological exploration of the 1,4-naphthoquinone nucleus as a primary pharmacophore in our search for new chemical entities which can induce apoptosis in oesophageal cancer cells, thus contributing to our overall ongoing SAR study in this class of compounds. Seven new naphthoquinone derivatves (4.19, 4.30, 4.31, 4.33 and 4.46-4.48) of the natural products 2-deoxylapachol (2.44), lapachol (4.1) and β-lapachone (5.2) were synthesized and 2-(1`-hydroxy-`-phenylmethyl)-1,4-naphthoquinone (4.29) was found to be the most cytotoxic (IC50 1.5 μM) against the oesophageal cancer cell line WHCO1, while 5.2, which is currently in phase II clinical trials as an anticancer drug, was found to be similarly active (IC50 1.6 μM). Electrochemical investigations of the redox properties of the benzylic alcohol derivatives 4.29-4.31 indicated a higher reduction potential compared to their oxidized counterparts 4.45-4.48, and this finding has been correlated to the increased activity of 4.29-4.31 against the WHCO1 cell line. Additionally, 4.29 is synthetically more accessible than either 1.26 or 5.2 and potentially a lead compound in our search for new and more effective chemotherapeutic agents against oesophageal cancer
- Full Text:
- Date Issued: 2011
How integrated are the African stock exchanges?: evidence from long term comovement, returns and volatility spillovers
- Kambadza, Tinashe Harry Dumile
- Authors: Kambadza, Tinashe Harry Dumile
- Date: 2011
- Subjects: Stock exchanges -- Africa Money market -- Africa Globalization -- Economic aspects -- Africa International economic relations
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1017 , http://hdl.handle.net/10962/d1002752
- Description: Stock market linkages have implications for portfolio diversification, asset pricing, monetary and regulatory policy as well as financial stability. This study examines the extent to which African stock markets are linked using daily data for the period 2000-2010. The study is divided into three main parts each focussing on the ways in which integration of the stock markets can be viewed. Firstly, we analyse the long run co-movement of the stock markets using both bivariate and multivariate Johansen (1988) and Johansen and Juselius (1990) cointegration approaches. Secondly, we analyse returns linkages using Factor analysis and the Vector Autoregressive (VAR) models. In the Factor Analysis model, we used two extraction methods, namely Principal Component Analysis and the Maximurn Likelihood technique. The VAR model was extended with impulse response, variance decomposition and block exogeniety. Thirdly, we analyse the behaviour of volatility and the volatility linkages among the stock markets. We initially analysed and modelled volatility in each stock market using the GARCH, EGARCH and GJR GARCH and then examined the long-term trend of the volatility. Conditional volatility series for each country were then estimated using the most appropriate model and were analysed using VAR, block exogeniety, impulse response and variance decomposition to determine the extent of their linkages. The findings of the study are as follows: Both the bivariate and multivariate models found slim evidence of cointegration amongst the stock markets, suggesting that there were opportunities for portfolio diversification for investors. In general, the financial crisis had very little impact on the long-run relationships of the stock markets. Results for the returns linkages showed that there were limited retums linkages with the exceptions of South African-Namibia and Egypt-Morocco to a lesser extent. South Africa was found to be the most endogenous, whilst Ghana and Nigeria were the most exogenous on the continent. We regards to volatility, we found that it was asymmetric and persistent across all the stock markets with long term trend of volatility showing that it significantly increased for most of the markets. Finally, there were limited volatility linkages, only between South Africa, Egypt and Namibia, implying that African stock markets are still largely segmented from each other. However, the linkages between South Africa and Egypt could have negative effects as they could lead to the spread of contagion effects during times of crises. Therefore, policymakers should consider revising and improving policies to enhance economic integration on the continent.
- Full Text:
- Date Issued: 2011
- Authors: Kambadza, Tinashe Harry Dumile
- Date: 2011
- Subjects: Stock exchanges -- Africa Money market -- Africa Globalization -- Economic aspects -- Africa International economic relations
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1017 , http://hdl.handle.net/10962/d1002752
- Description: Stock market linkages have implications for portfolio diversification, asset pricing, monetary and regulatory policy as well as financial stability. This study examines the extent to which African stock markets are linked using daily data for the period 2000-2010. The study is divided into three main parts each focussing on the ways in which integration of the stock markets can be viewed. Firstly, we analyse the long run co-movement of the stock markets using both bivariate and multivariate Johansen (1988) and Johansen and Juselius (1990) cointegration approaches. Secondly, we analyse returns linkages using Factor analysis and the Vector Autoregressive (VAR) models. In the Factor Analysis model, we used two extraction methods, namely Principal Component Analysis and the Maximurn Likelihood technique. The VAR model was extended with impulse response, variance decomposition and block exogeniety. Thirdly, we analyse the behaviour of volatility and the volatility linkages among the stock markets. We initially analysed and modelled volatility in each stock market using the GARCH, EGARCH and GJR GARCH and then examined the long-term trend of the volatility. Conditional volatility series for each country were then estimated using the most appropriate model and were analysed using VAR, block exogeniety, impulse response and variance decomposition to determine the extent of their linkages. The findings of the study are as follows: Both the bivariate and multivariate models found slim evidence of cointegration amongst the stock markets, suggesting that there were opportunities for portfolio diversification for investors. In general, the financial crisis had very little impact on the long-run relationships of the stock markets. Results for the returns linkages showed that there were limited retums linkages with the exceptions of South African-Namibia and Egypt-Morocco to a lesser extent. South Africa was found to be the most endogenous, whilst Ghana and Nigeria were the most exogenous on the continent. We regards to volatility, we found that it was asymmetric and persistent across all the stock markets with long term trend of volatility showing that it significantly increased for most of the markets. Finally, there were limited volatility linkages, only between South Africa, Egypt and Namibia, implying that African stock markets are still largely segmented from each other. However, the linkages between South Africa and Egypt could have negative effects as they could lead to the spread of contagion effects during times of crises. Therefore, policymakers should consider revising and improving policies to enhance economic integration on the continent.
- Full Text:
- Date Issued: 2011
The druggable antimalarial target 1-deoxy-D-xylulose-5-phosphate reductoisomerase: purfication, kinetic characterization and inhibition studies
- Authors: Goble, Jessica Leigh
- Date: 2011
- Subjects: Antimalarials -- Development Plasmodium falciparum Drug development Plasmodium falciparum -- Purification Plasmodium falciparum -- Inhibitors Enzyme kinetics Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3949 , http://hdl.handle.net/10962/d1004008
- Description: Plasmodium falciparum 1–deoxy–D–xylulose–5 phosphatereductoisomerase (PfDXR) plays a role in isoprenoid biosynthesis in the malaria parasite and is absent in the human host, making this parasite enzyme an attractive target for antimalarial drug design. To characterize PfDXR, it is necessary to produce large quantities of the enzyme in a soluble and functional form. However, the over–production of malarial proteins in prokaryotic host systems often results in the formation of truncated proteins or insoluble protein aggregates. A heterologous expression system was developed for the production of active PfDXR using codon harmonization and tight control of expression in the presence of lac repressor. Yields of up to 2 mg/l of enzyme were reported using the optimised expression system, which is 8 to 10– fold greater than previously reported yields. The kinetic parameters Km, Vmax and kcat were determined for PfDXR; values reported in this study were consistent with those reported in the literature for other DXR enzymes. A three–dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure–checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non–apicomplexan DXR proteins. Residues Val44 and Asn45, essential for NADPH binding; and catalytic hatch residues Lys224 and Lys226, which are unique to the species of Plasmodium, were mutated to resemble those of E. coli DXR. Interestingly,these mutations resulted in significant reductions in substrate affinity, when compared to the unmutated PfDXR. Mutant enzymes PfDXR(VN43,44AG) and PfDXR(KK224,226NS) also demonstrated a decreased ability to turnover substrate by 4–fold and 2–fold respectively. This study indicates a difference in the role of the catalytic hatch of PfDXR with regards to the way in which it captures substrates. The study also highlights subtle differences in cofactor binding to PfDXR, compared with the well characterized EcDXR enzyme. The validated PfDXR model was also used to develop a novel efficient in silico screening method for potential tool compounds for use in the rational design of novel DXR inhibitors. Following in silico screening of 46 potential DXR inhibitors, a two–tiered in vitro screening approach was undertaken. DXR inhibition was assessed for the 46 novel compounds using an NADPH– ependant DXP enzyme inhibition assay and antimalarial potential was assessed using P.falciparum–infected erythrocyte growth assays. Select compounds were tested in human cells in order to determine whether they were toxic to the host. From the parallel in silico and in vitro drug screening, it was evident that only a single compound demonstrated reasonable potential binding to DXR (determined using in silico docking), inhibited DXR in vitro and inhibited P. falciparum growth, without being toxic to human cells. Its potential as a lead compound in antimalarial drug development is therefore feasible. Two outcomes were evident from this work. Firstly, analogues of known antimalarial natural products can be screened against malaria, which may then lead towards the rational design of novel compounds that are effective against a specific antimalarial drug target enzyme, such as PfDXR. Secondly, the rational design of novel compounds against a specific antimalarial drug target enzyme can be untaken by adopting a coupled in silico and in vitro approach to drug discovery.
- Full Text:
- Date Issued: 2011
- Authors: Goble, Jessica Leigh
- Date: 2011
- Subjects: Antimalarials -- Development Plasmodium falciparum Drug development Plasmodium falciparum -- Purification Plasmodium falciparum -- Inhibitors Enzyme kinetics Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3949 , http://hdl.handle.net/10962/d1004008
- Description: Plasmodium falciparum 1–deoxy–D–xylulose–5 phosphatereductoisomerase (PfDXR) plays a role in isoprenoid biosynthesis in the malaria parasite and is absent in the human host, making this parasite enzyme an attractive target for antimalarial drug design. To characterize PfDXR, it is necessary to produce large quantities of the enzyme in a soluble and functional form. However, the over–production of malarial proteins in prokaryotic host systems often results in the formation of truncated proteins or insoluble protein aggregates. A heterologous expression system was developed for the production of active PfDXR using codon harmonization and tight control of expression in the presence of lac repressor. Yields of up to 2 mg/l of enzyme were reported using the optimised expression system, which is 8 to 10– fold greater than previously reported yields. The kinetic parameters Km, Vmax and kcat were determined for PfDXR; values reported in this study were consistent with those reported in the literature for other DXR enzymes. A three–dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure–checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non–apicomplexan DXR proteins. Residues Val44 and Asn45, essential for NADPH binding; and catalytic hatch residues Lys224 and Lys226, which are unique to the species of Plasmodium, were mutated to resemble those of E. coli DXR. Interestingly,these mutations resulted in significant reductions in substrate affinity, when compared to the unmutated PfDXR. Mutant enzymes PfDXR(VN43,44AG) and PfDXR(KK224,226NS) also demonstrated a decreased ability to turnover substrate by 4–fold and 2–fold respectively. This study indicates a difference in the role of the catalytic hatch of PfDXR with regards to the way in which it captures substrates. The study also highlights subtle differences in cofactor binding to PfDXR, compared with the well characterized EcDXR enzyme. The validated PfDXR model was also used to develop a novel efficient in silico screening method for potential tool compounds for use in the rational design of novel DXR inhibitors. Following in silico screening of 46 potential DXR inhibitors, a two–tiered in vitro screening approach was undertaken. DXR inhibition was assessed for the 46 novel compounds using an NADPH– ependant DXP enzyme inhibition assay and antimalarial potential was assessed using P.falciparum–infected erythrocyte growth assays. Select compounds were tested in human cells in order to determine whether they were toxic to the host. From the parallel in silico and in vitro drug screening, it was evident that only a single compound demonstrated reasonable potential binding to DXR (determined using in silico docking), inhibited DXR in vitro and inhibited P. falciparum growth, without being toxic to human cells. Its potential as a lead compound in antimalarial drug development is therefore feasible. Two outcomes were evident from this work. Firstly, analogues of known antimalarial natural products can be screened against malaria, which may then lead towards the rational design of novel compounds that are effective against a specific antimalarial drug target enzyme, such as PfDXR. Secondly, the rational design of novel compounds against a specific antimalarial drug target enzyme can be untaken by adopting a coupled in silico and in vitro approach to drug discovery.
- Full Text:
- Date Issued: 2011
The diversity of aquatic insects in the Tsitsikamma region, with implications for aquatic ecosystem conservation
- Authors: Bellingan, Terence Andrew
- Date: 2011
- Subjects: Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5664 , http://hdl.handle.net/10962/d1005348 , Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Description: As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.
- Full Text:
- Date Issued: 2011
- Authors: Bellingan, Terence Andrew
- Date: 2011
- Subjects: Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5664 , http://hdl.handle.net/10962/d1005348 , Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Description: As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.
- Full Text:
- Date Issued: 2011
Raw phones: the domestication of mobile phones amongst young adults in Hooggenoeg, Grahamstown
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
- Date Issued: 2011
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
- Date Issued: 2011
The zoogeography of the cetaceans in Algoa Bay
- Authors: Melly, Brigitte Leigh
- Date: 2011
- Subjects: Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4858 , http://hdl.handle.net/10962/d1005534 , Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Description: The most recent study on cetaceans in Algoa Bay, South Africa, was conducted over 14 years ago. Consequently, knowledge of the cetacean species visiting this bay is currently based on incidental observations and stranding data. A number of developments in recent years: a deepwater port, proposed oil refinery, increased boating and fishing (commercial and recreational), a proposed Marine Protected Area, and the release of a whale-watching permit, all of which may impact these animals in some way, highlight the need for a baseline study on cetaceans. Therefore, the aim of this study was to determine the spatial and temporal distribution, and habitat preference of cetaceans in Algoa Bay. Boat-based surveys were conducted monthly between March 2009 and July 2010. At each sighting the GPS location, species, group size and composition, and behaviour were recorded. Using GIS, the sighting data was related to data layers of geographical variables such as sea surface temperature, depth and sea-floor substrate. Approximately 365 hours of search effort were completed over 57 surveys, with a total of 346 sightings. Species observed were: southern right whales (Eubalaena australis), humpback whales (Megaptera novaeangliae), Bryde’s whales (Balaenoptera brydei), Indian Ocean bottlenose dolphins (Tursiops aduncus), Indo-Pacific humpback dolphins (Sousa chinensis), and longbeaked common dolphins (Delphinus capensis). Southern right whales were observed during austral winter, utilising the shallow, protected areas of the bay as a mating and nursery ground. Humpback whales were also recorded extensively during winter, in more offshore waters, with a significant number of mother-calf pairs sighted. Bryde’s whales were recorded in offshore waters during summer and autumn, where they were primarily observed travelling and foraging. Bottlenose dolphins were the most prolific species sighted. They were recorded year-round throughout the inshore waters of the bay, with large group sizes (up to 500 animals), and displayed a wide variety of behaviours. Humpback dolphins were observed in extremely shallow and inshore waters (mean bottom depth of 6.6 m) along the south-west corner of the bay, in small groups of approximately three individuals. Common dolphins were the least observed species, and were mainly observed foraging in large groups of up to 800 individuals. The results of this study indicate how cetaceans utilise the bay in significantly different ways. Geographical and anthropogenic factors have influenced the spatial and temporal distribution of these animals and have resulted in habitat preferences, as well as potential key habitats, in the bay. Thus, this study has provided baseline information for future research and for better informed conservation and management strategies in Algoa Bay.
- Full Text:
- Date Issued: 2011
- Authors: Melly, Brigitte Leigh
- Date: 2011
- Subjects: Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4858 , http://hdl.handle.net/10962/d1005534 , Cetacea -- South Africa -- Algoa Bay , Cetacea -- Behavior -- South Africa -- Algoa Bay , Cetacea -- South Africa -- Algoa Bay -- Geographical distribution , Cetacea -- Counting -- South Africa -- Algoa Bay
- Description: The most recent study on cetaceans in Algoa Bay, South Africa, was conducted over 14 years ago. Consequently, knowledge of the cetacean species visiting this bay is currently based on incidental observations and stranding data. A number of developments in recent years: a deepwater port, proposed oil refinery, increased boating and fishing (commercial and recreational), a proposed Marine Protected Area, and the release of a whale-watching permit, all of which may impact these animals in some way, highlight the need for a baseline study on cetaceans. Therefore, the aim of this study was to determine the spatial and temporal distribution, and habitat preference of cetaceans in Algoa Bay. Boat-based surveys were conducted monthly between March 2009 and July 2010. At each sighting the GPS location, species, group size and composition, and behaviour were recorded. Using GIS, the sighting data was related to data layers of geographical variables such as sea surface temperature, depth and sea-floor substrate. Approximately 365 hours of search effort were completed over 57 surveys, with a total of 346 sightings. Species observed were: southern right whales (Eubalaena australis), humpback whales (Megaptera novaeangliae), Bryde’s whales (Balaenoptera brydei), Indian Ocean bottlenose dolphins (Tursiops aduncus), Indo-Pacific humpback dolphins (Sousa chinensis), and longbeaked common dolphins (Delphinus capensis). Southern right whales were observed during austral winter, utilising the shallow, protected areas of the bay as a mating and nursery ground. Humpback whales were also recorded extensively during winter, in more offshore waters, with a significant number of mother-calf pairs sighted. Bryde’s whales were recorded in offshore waters during summer and autumn, where they were primarily observed travelling and foraging. Bottlenose dolphins were the most prolific species sighted. They were recorded year-round throughout the inshore waters of the bay, with large group sizes (up to 500 animals), and displayed a wide variety of behaviours. Humpback dolphins were observed in extremely shallow and inshore waters (mean bottom depth of 6.6 m) along the south-west corner of the bay, in small groups of approximately three individuals. Common dolphins were the least observed species, and were mainly observed foraging in large groups of up to 800 individuals. The results of this study indicate how cetaceans utilise the bay in significantly different ways. Geographical and anthropogenic factors have influenced the spatial and temporal distribution of these animals and have resulted in habitat preferences, as well as potential key habitats, in the bay. Thus, this study has provided baseline information for future research and for better informed conservation and management strategies in Algoa Bay.
- Full Text:
- Date Issued: 2011
A platform for computer-assisted multilingual literacy development
- Authors: Mudimba, Bwini Chizabubi
- Date: 2011
- Subjects: FundaWethu , Language acquisition -- Computer-assisted instruction , Language arts (Elementary) -- Computer-assisted instruction , Language and education , Education, Bilingual , Computer-assisted instruction , Educational technology , Computers and literacy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4600 , http://hdl.handle.net/10962/d1004850 , FundaWethu , Language acquisition -- Computer-assisted instruction , Language arts (Elementary) -- Computer-assisted instruction , Language and education , Education, Bilingual , Computer-assisted instruction , Educational technology , Computers and literacy
- Description: FundaWethu is reading software that is designed to deliver reading lessons to Grade R-3 (foundation phase) children who are learning to read in a multilingual context. Starting from a premise that the system should be both educative and entertaining, the system allows literacy researchers or teachers to construct rich multimedia reading lessons, with text, pictures (possibly animated), and audio files. Using the design-based research methodology which is problem driven and iterative, we followed a user-centred design process in creating FundaWethu. To promote sustainability of the software, we chose to bring teachers on board as “co-designers” using the lesson authoring tool. We made the authoring tool simple enough for use by non computer specialists, but expressive enough to enable a wide range of beginners reading exercises to be constructed in a number of different languages (indigenous South African languages in particular). This project therefore centred on the use of designbased research to build FundaWethu, the design and construction of FundaWethu and the usability study carried out to determine the adequacy of FundaWethu.
- Full Text:
- Date Issued: 2011
- Authors: Mudimba, Bwini Chizabubi
- Date: 2011
- Subjects: FundaWethu , Language acquisition -- Computer-assisted instruction , Language arts (Elementary) -- Computer-assisted instruction , Language and education , Education, Bilingual , Computer-assisted instruction , Educational technology , Computers and literacy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4600 , http://hdl.handle.net/10962/d1004850 , FundaWethu , Language acquisition -- Computer-assisted instruction , Language arts (Elementary) -- Computer-assisted instruction , Language and education , Education, Bilingual , Computer-assisted instruction , Educational technology , Computers and literacy
- Description: FundaWethu is reading software that is designed to deliver reading lessons to Grade R-3 (foundation phase) children who are learning to read in a multilingual context. Starting from a premise that the system should be both educative and entertaining, the system allows literacy researchers or teachers to construct rich multimedia reading lessons, with text, pictures (possibly animated), and audio files. Using the design-based research methodology which is problem driven and iterative, we followed a user-centred design process in creating FundaWethu. To promote sustainability of the software, we chose to bring teachers on board as “co-designers” using the lesson authoring tool. We made the authoring tool simple enough for use by non computer specialists, but expressive enough to enable a wide range of beginners reading exercises to be constructed in a number of different languages (indigenous South African languages in particular). This project therefore centred on the use of designbased research to build FundaWethu, the design and construction of FundaWethu and the usability study carried out to determine the adequacy of FundaWethu.
- Full Text:
- Date Issued: 2011
Effect of nanoparticles on the photophysicochemical behaviour of metallophthalocyanines
- Moeno, Sharon Keitumetse Gail Mpheletso
- Authors: Moeno, Sharon Keitumetse Gail Mpheletso
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Nanoparticles Photochemistry Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4310 , http://hdl.handle.net/10962/d1004968
- Description: The synthesis, spectroscopic characterization, and studies of the photophysicochemical behaviour of selective anionic, cationic and neutral metallophthallocyanine (MPc) complexes were carried out and the results are presented herein. Studies on the effect of the central metal ion, the solvent used and the presence of nanoparticles on the photophysicochemical properties were conducted. The findings showed that the photophysicochemical parameters were mostly enhanced in the presence of central metal ions of high atomic numbers and also in the presence of nanoparticles. It was also observed that solvents that encouraged the monomericity of the MPc complexes also lead to improved photophysical and photochemical behaviour. CdTe quantum dots (QDs) stabilized with mercaptocarbonic acids were also observed to cause stimulated emission of the MPcs through Förster resonance energy transfer (FRET) thus acting as energy donors while the respective MPc acted as energy acceptors in all the FRET studies. FRET was observed following the photoexcitation of QDs for all monomeric anionic MPcs but it was also shown to occur for some cationic MPcs in organic media. Both the substituent and solvent used were found to exert a strong influence on the occurrence of FRET. Other cationic MPcs however showed different behaviour in the presence of the meraptocarbonic stabilized CdTe QDs; with the cationic porphyrazine giving clear indications of Pc ring reduction. The rest of the cationic MPcs did not give clear evidence of Pc ring reduction, instead they showed signs of aggregate formation possibly from the assembly of electrostatic ion pair complexes which could result in reduction of the quaternized pyridinium ring of the substituent. Both the QDs and the MPc complex emission spectra were significantly quenched for each in the presence of the other. Stern-Volmer quenching studies indicated that both static and dynamic quenching of the QDs in the presence of MPcs took place. The fluorescence lifetimes of the mercaptopropionic acid (MPA) capped CdTe QDs in the presence of various MPc complexes showed quenching of mostly the longer lifetimes of the QDs in the presence of MPcs suggesting that the surface defects and states are involved in the interaction of the QDs and MPcs. An MPc complex terminating in thio tethers was employed in the conjugation to AuNPs. Spectroscopic and microscopic studies confirmed the formation of the MPc-AuNP conjugate which was also shown to exhibit improved photophysicochemical properties compared to the free MPc.
- Full Text:
- Date Issued: 2011
- Authors: Moeno, Sharon Keitumetse Gail Mpheletso
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Nanoparticles Photochemistry Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4310 , http://hdl.handle.net/10962/d1004968
- Description: The synthesis, spectroscopic characterization, and studies of the photophysicochemical behaviour of selective anionic, cationic and neutral metallophthallocyanine (MPc) complexes were carried out and the results are presented herein. Studies on the effect of the central metal ion, the solvent used and the presence of nanoparticles on the photophysicochemical properties were conducted. The findings showed that the photophysicochemical parameters were mostly enhanced in the presence of central metal ions of high atomic numbers and also in the presence of nanoparticles. It was also observed that solvents that encouraged the monomericity of the MPc complexes also lead to improved photophysical and photochemical behaviour. CdTe quantum dots (QDs) stabilized with mercaptocarbonic acids were also observed to cause stimulated emission of the MPcs through Förster resonance energy transfer (FRET) thus acting as energy donors while the respective MPc acted as energy acceptors in all the FRET studies. FRET was observed following the photoexcitation of QDs for all monomeric anionic MPcs but it was also shown to occur for some cationic MPcs in organic media. Both the substituent and solvent used were found to exert a strong influence on the occurrence of FRET. Other cationic MPcs however showed different behaviour in the presence of the meraptocarbonic stabilized CdTe QDs; with the cationic porphyrazine giving clear indications of Pc ring reduction. The rest of the cationic MPcs did not give clear evidence of Pc ring reduction, instead they showed signs of aggregate formation possibly from the assembly of electrostatic ion pair complexes which could result in reduction of the quaternized pyridinium ring of the substituent. Both the QDs and the MPc complex emission spectra were significantly quenched for each in the presence of the other. Stern-Volmer quenching studies indicated that both static and dynamic quenching of the QDs in the presence of MPcs took place. The fluorescence lifetimes of the mercaptopropionic acid (MPA) capped CdTe QDs in the presence of various MPc complexes showed quenching of mostly the longer lifetimes of the QDs in the presence of MPcs suggesting that the surface defects and states are involved in the interaction of the QDs and MPcs. An MPc complex terminating in thio tethers was employed in the conjugation to AuNPs. Spectroscopic and microscopic studies confirmed the formation of the MPc-AuNP conjugate which was also shown to exhibit improved photophysicochemical properties compared to the free MPc.
- Full Text:
- Date Issued: 2011
Financial system development and economic growth in selected African countries: evidence from a panel cointegration analysis
- Authors: Starkey, Randall Ashley
- Date: 2011
- Subjects: Economic development -- Africa Economic development -- Developing countries Banks and banking -- Africa Banks and banking -- Developing countries Stock exchanges -- Africa Stock exchanges -- Developing countries Econometric models Economic policy -- Africa Economic policy -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:979 , http://hdl.handle.net/10962/d1002713
- Description: Financial systems (i.e. banking systems and stock markets) can influence economic growth by performing the five key financial functions, namely: mobilising savings, allocating capital, easing of exchange, monitoring and exerting corporate governance, as well as ameliorating risk. The level of development of the financial system is a key determinant of how effectively and efficiently these functions are performed. This study examines the short-run and long-run relationships between financial system development and economic growth for a panel of seven African countries (namely: Egypt, Ivory Coast, Kenya, Morocco, Nigeria, South Africa and Tunisia) covering the period 1988 to 2008. While numerous empirical studies have researched this topic, none of the previous African empirical literature have investigated thjs by using three groups of financial development measures (i.e. overall financial development, banking system development and stock market development measures) as well as employing panel cointegration analyses. The investigation of the long-run finance-growth relationship is conducted using two methods; the Pedroni panel cointegration approach and the Kao panel cointegration technique. The Pedroni panel cointegracion approach is more often applied in empirical research as it has less restrictive deterministic trend assumptions, while the Kao panel cointegration technique is employed in this study for comparison purposes. Furthermore, the short-run linkages bet\veen financial development and economic growth are analysed using the Holtz-Eakin d of (1989) panel Granger causality test. The results of the Pedroni cointegration tests show that there are long-run relationships between overall financial development (measured by LOFD and OFD2) and economic growth, banking system development (measured by LPSC) and economic growth, as well as stock marker development (measured by LMCP and LVLT) and economic growth. In contrast, the Kao test fails to find any cointegration between finance and growth. However, on the balance, findings largely support a conclusion of cointegration between financial development and economic growth since the Pedroni approach is more appropriate for examining cointegration in heterogeneous panels. Estimates of these long-run cointegrating relationships show that all five financial development measures have the expected positive linkages with growth. However, only four of the five financial development measures were found to have significant long-run linkages with growth, as the relationship between LOFD and growth was not found to be significant in the long-run. The panel Granger causality results show that economic growth Granger causes banking system development in the short-run (i.e. there is demand-following finance), irrespective of the measure of banking development used. While there is bi-directional, reciprocal causality between economic growth and both of the measures of overall financial development and one measure of srock market development (i.e. LVLT). Thus, pulicy makers should focus on formulating policy which promotes faster paced economic growth so as to stimulate financial development, while at the same time encourage policy that promotes the balanced expansion of the banking systems and srock markets in ordet to augment economic growth.
- Full Text:
- Date Issued: 2011
- Authors: Starkey, Randall Ashley
- Date: 2011
- Subjects: Economic development -- Africa Economic development -- Developing countries Banks and banking -- Africa Banks and banking -- Developing countries Stock exchanges -- Africa Stock exchanges -- Developing countries Econometric models Economic policy -- Africa Economic policy -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:979 , http://hdl.handle.net/10962/d1002713
- Description: Financial systems (i.e. banking systems and stock markets) can influence economic growth by performing the five key financial functions, namely: mobilising savings, allocating capital, easing of exchange, monitoring and exerting corporate governance, as well as ameliorating risk. The level of development of the financial system is a key determinant of how effectively and efficiently these functions are performed. This study examines the short-run and long-run relationships between financial system development and economic growth for a panel of seven African countries (namely: Egypt, Ivory Coast, Kenya, Morocco, Nigeria, South Africa and Tunisia) covering the period 1988 to 2008. While numerous empirical studies have researched this topic, none of the previous African empirical literature have investigated thjs by using three groups of financial development measures (i.e. overall financial development, banking system development and stock market development measures) as well as employing panel cointegration analyses. The investigation of the long-run finance-growth relationship is conducted using two methods; the Pedroni panel cointegration approach and the Kao panel cointegration technique. The Pedroni panel cointegracion approach is more often applied in empirical research as it has less restrictive deterministic trend assumptions, while the Kao panel cointegration technique is employed in this study for comparison purposes. Furthermore, the short-run linkages bet\veen financial development and economic growth are analysed using the Holtz-Eakin d of (1989) panel Granger causality test. The results of the Pedroni cointegration tests show that there are long-run relationships between overall financial development (measured by LOFD and OFD2) and economic growth, banking system development (measured by LPSC) and economic growth, as well as stock marker development (measured by LMCP and LVLT) and economic growth. In contrast, the Kao test fails to find any cointegration between finance and growth. However, on the balance, findings largely support a conclusion of cointegration between financial development and economic growth since the Pedroni approach is more appropriate for examining cointegration in heterogeneous panels. Estimates of these long-run cointegrating relationships show that all five financial development measures have the expected positive linkages with growth. However, only four of the five financial development measures were found to have significant long-run linkages with growth, as the relationship between LOFD and growth was not found to be significant in the long-run. The panel Granger causality results show that economic growth Granger causes banking system development in the short-run (i.e. there is demand-following finance), irrespective of the measure of banking development used. While there is bi-directional, reciprocal causality between economic growth and both of the measures of overall financial development and one measure of srock market development (i.e. LVLT). Thus, pulicy makers should focus on formulating policy which promotes faster paced economic growth so as to stimulate financial development, while at the same time encourage policy that promotes the balanced expansion of the banking systems and srock markets in ordet to augment economic growth.
- Full Text:
- Date Issued: 2011
Improved tree species discrimination at leaf level with hyperspectral data combining binary classifiers
- Authors: Dastile, Xolani Collen
- Date: 2011
- Subjects: Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5567 , http://hdl.handle.net/10962/d1002807 , Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Description: The purpose of the present thesis is to show that hyperspectral data can be used for discrimination between different tree species. The data set used in this study contains the hyperspectral measurements of leaves of seven savannah tree species. The data is high-dimensional and shows large within-class variability combined with small between-class variability which makes discrimination between the classes challenging. We employ two classification methods: G-nearest neighbour and feed-forward neural networks. For both methods, direct 7-class prediction results in high misclassification rates. However, binary classification works better. We constructed binary classifiers for all possible binary classification problems and combine them with Error Correcting Output Codes. We show especially that the use of 1-nearest neighbour binary classifiers results in no improvement compared to a direct 1-nearest neighbour 7-class predictor. In contrast to this negative result, the use of neural networks binary classifiers improves accuracy by 10% compared to a direct neural networks 7-class predictor, and error rates become acceptable. This can be further improved by choosing only suitable binary classifiers for combination.
- Full Text:
- Date Issued: 2011
- Authors: Dastile, Xolani Collen
- Date: 2011
- Subjects: Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5567 , http://hdl.handle.net/10962/d1002807 , Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Description: The purpose of the present thesis is to show that hyperspectral data can be used for discrimination between different tree species. The data set used in this study contains the hyperspectral measurements of leaves of seven savannah tree species. The data is high-dimensional and shows large within-class variability combined with small between-class variability which makes discrimination between the classes challenging. We employ two classification methods: G-nearest neighbour and feed-forward neural networks. For both methods, direct 7-class prediction results in high misclassification rates. However, binary classification works better. We constructed binary classifiers for all possible binary classification problems and combine them with Error Correcting Output Codes. We show especially that the use of 1-nearest neighbour binary classifiers results in no improvement compared to a direct 1-nearest neighbour 7-class predictor. In contrast to this negative result, the use of neural networks binary classifiers improves accuracy by 10% compared to a direct neural networks 7-class predictor, and error rates become acceptable. This can be further improved by choosing only suitable binary classifiers for combination.
- Full Text:
- Date Issued: 2011
An analysis of the long run comovements between financial system development and mining production in South Africa
- Authors: Ajagbe, Stephen Mayowa
- Date: 2011
- Subjects: Economic development -- South Africa , Econometric models , Mineral industries -- Economic aspects -- South Africa , South Africa -- Economic conditions , South Africa -- Economic policy , Principal components analysis , Cointegration , Stock exchanges -- South Africa , Banks and banking -- South Africa , Foreign exchange rates
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:955 , http://hdl.handle.net/10962/d1002689 , Economic development -- South Africa , Econometric models , Mineral industries -- Economic aspects -- South Africa , South Africa -- Economic conditions , South Africa -- Economic policy , Principal components analysis , Cointegration , Stock exchanges -- South Africa , Banks and banking -- South Africa , Foreign exchange rates
- Description: This study examines the nature of the relationship which exists between mining sector production and development of the financial systems in South Africa. This is particularly important in that the mining sector is considered to be one of the major contributors to the country’s overall economic growth. South Africa is also considered to have a very well developed financial system, to the point where the dominance of one over the other is difficult to identify. Therefore offering insight into the nature of this relationship will assist policy makers in identifying the most effective policies in order to ensure that the developments within the financial systems impact appropriately on the mining sector, and ultimately on the economy. In addition to using the conventional proxies of financial system development, this study utilises the principal component analysis (PCA) to construct an index for the entire financial system. The multivariate cointegration approach as proposed by Johansen (1988) and Johansen and Juselius (1990) was then used to estimate the relationship between the development of the financial systems and the mining sector production for the period 1988-2008. The study reveals mixed results for different measures of financial system development. Those involving the banking system show that a negative relationship exists between total mining production and total credit extended to the private sector, while liquid liabilities has a positive relationship. Similarly, with the stock market system, mixed results are also obtained which reveal a negative relationship between total mining production and stock market capitalisation, while a positive relationship is found with secondary market turnover. Of all the financial system variables, only that of stock market capitalisation was found to be significant. The result with the financial development index reveals that a significant negative relationship exists between financial system development and total mining sector production. Results on the other variables controlled in the estimation show that positive and significant relationships exist between total mining production and both nominal exchange rate and political stability respectively. Increased mining production therefore takes place in periods of appreciating exchange rates, and similarly in the post-apartheid era. On the other hand, negative relationships were found for both trade openness and inflation control variables. The impulse response and variance decomposition analyses showed that total mining production explains the largest amount of shocks within itself. Overall, the study reveals that the mining sector might not have benefited much from the development in the South African financial system.
- Full Text:
- Date Issued: 2011
- Authors: Ajagbe, Stephen Mayowa
- Date: 2011
- Subjects: Economic development -- South Africa , Econometric models , Mineral industries -- Economic aspects -- South Africa , South Africa -- Economic conditions , South Africa -- Economic policy , Principal components analysis , Cointegration , Stock exchanges -- South Africa , Banks and banking -- South Africa , Foreign exchange rates
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:955 , http://hdl.handle.net/10962/d1002689 , Economic development -- South Africa , Econometric models , Mineral industries -- Economic aspects -- South Africa , South Africa -- Economic conditions , South Africa -- Economic policy , Principal components analysis , Cointegration , Stock exchanges -- South Africa , Banks and banking -- South Africa , Foreign exchange rates
- Description: This study examines the nature of the relationship which exists between mining sector production and development of the financial systems in South Africa. This is particularly important in that the mining sector is considered to be one of the major contributors to the country’s overall economic growth. South Africa is also considered to have a very well developed financial system, to the point where the dominance of one over the other is difficult to identify. Therefore offering insight into the nature of this relationship will assist policy makers in identifying the most effective policies in order to ensure that the developments within the financial systems impact appropriately on the mining sector, and ultimately on the economy. In addition to using the conventional proxies of financial system development, this study utilises the principal component analysis (PCA) to construct an index for the entire financial system. The multivariate cointegration approach as proposed by Johansen (1988) and Johansen and Juselius (1990) was then used to estimate the relationship between the development of the financial systems and the mining sector production for the period 1988-2008. The study reveals mixed results for different measures of financial system development. Those involving the banking system show that a negative relationship exists between total mining production and total credit extended to the private sector, while liquid liabilities has a positive relationship. Similarly, with the stock market system, mixed results are also obtained which reveal a negative relationship between total mining production and stock market capitalisation, while a positive relationship is found with secondary market turnover. Of all the financial system variables, only that of stock market capitalisation was found to be significant. The result with the financial development index reveals that a significant negative relationship exists between financial system development and total mining sector production. Results on the other variables controlled in the estimation show that positive and significant relationships exist between total mining production and both nominal exchange rate and political stability respectively. Increased mining production therefore takes place in periods of appreciating exchange rates, and similarly in the post-apartheid era. On the other hand, negative relationships were found for both trade openness and inflation control variables. The impulse response and variance decomposition analyses showed that total mining production explains the largest amount of shocks within itself. Overall, the study reveals that the mining sector might not have benefited much from the development in the South African financial system.
- Full Text:
- Date Issued: 2011
The development of isiZulu as an academic language for the teaching of fundamental concepts in economics
- Authors: Makhatini, Freedom Nkanyiso
- Date: 2011
- Subjects: Zulu language -- Study and teaching (Higher) -- South Africa African languages -- Study and teaching (Higher) -- South Africa Economics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3589 , http://hdl.handle.net/10962/d1002164
- Description: This thesis looks at language as the medium of all our ideas and sentiments. The thesis represents a position statement regarding the development of isiZulu as an academic language. The field of Economics is used to merely illustrate and support the points that are being made in this work. It is argued that each language is viewed as the means of expression of the cultural heritage of its people, and it remains a reflection of cultural groups who speak that particular language. It is a fact that indigenous African Languages have been, for obvious reasons, blatantly understudied during the apartheid years in South Africa (Rudwick 2004). Languages have market value and the desirability of English as the most important global language today has an effect in most Black learners in South Africa. The study examined the development of indigenous African languages, isiZulu in particular, in Zululand University where ninety percent of students and lecturers are isiZulu first language speakers, and came to a conclusion that there is an urgent need for Black South African students to learn academic subjects through their mother tongues. This would help them in thorough understanding and interpretation of analytic text presented in a foreign language such as English. The study advocates that isiZulu, which is the mother-tongue of many students at the University of Zululand, should be a language for upward mobility to these students, but as the situation stands, isiZulu becomes a neglected or marginalised language since it is not the normal medium of instruction and it is not used for effective communication in their education system.
- Full Text:
- Date Issued: 2011
- Authors: Makhatini, Freedom Nkanyiso
- Date: 2011
- Subjects: Zulu language -- Study and teaching (Higher) -- South Africa African languages -- Study and teaching (Higher) -- South Africa Economics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3589 , http://hdl.handle.net/10962/d1002164
- Description: This thesis looks at language as the medium of all our ideas and sentiments. The thesis represents a position statement regarding the development of isiZulu as an academic language. The field of Economics is used to merely illustrate and support the points that are being made in this work. It is argued that each language is viewed as the means of expression of the cultural heritage of its people, and it remains a reflection of cultural groups who speak that particular language. It is a fact that indigenous African Languages have been, for obvious reasons, blatantly understudied during the apartheid years in South Africa (Rudwick 2004). Languages have market value and the desirability of English as the most important global language today has an effect in most Black learners in South Africa. The study examined the development of indigenous African languages, isiZulu in particular, in Zululand University where ninety percent of students and lecturers are isiZulu first language speakers, and came to a conclusion that there is an urgent need for Black South African students to learn academic subjects through their mother tongues. This would help them in thorough understanding and interpretation of analytic text presented in a foreign language such as English. The study advocates that isiZulu, which is the mother-tongue of many students at the University of Zululand, should be a language for upward mobility to these students, but as the situation stands, isiZulu becomes a neglected or marginalised language since it is not the normal medium of instruction and it is not used for effective communication in their education system.
- Full Text:
- Date Issued: 2011
An evaluation of the feasibility of obtaining payment for ecosystem services for the Baviaanskloof Nature Reserve
- Authors: Erlank, Wayne Michael
- Date: 2011
- Subjects: Ecosystem services -- South Africa -- Eastern Cape Ecology -- Economic aspects -- South Africa -- Eastern Cape Environmental economics -- South Africa -- Eastern Cape Water-supply -- South Africa -- Eastern Cape Water-supply -- South Africa -- Eastern Cape -- Management Water resources development -- South Africa -- Eastern Cape Nature conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:742 , http://hdl.handle.net/10962/d1003862
- Description: Cities must go further and further away to find new, more costly sources of water for human consumption while industries and agriculture continue to compete for increasingly scarce water resources. This may already be seen occurring within the Nelson Mandela Bay Metro where the severe drought being experienced during the past 18 months has severely depleted water supply dams. One of the main supply dams to the Nelson Mandela Bay Municipality is situated within the Baviaanskloof Nature Reserve and World Heritage Site. The potential of funding the Baviaanskloof Nature Reserve and World Heritage Site with payments for ecosystem services (water) obtained for water services supplied to the Nelson Mandela Bay Municipalities and agriculture in the Gamtoos River Valley will ensure financial sustainable for the Baviaanskloof Nature Reserve and World Heritage Site in the long term. This ability to become financially independent and generate its own income will place the Baviaanskloof Nature Reserve and World Heritage Site in a unique position within the conservation community in South Africa as only a very few protected areas are self sustaining through payment for an ecosystem service.
- Full Text:
- Date Issued: 2011
- Authors: Erlank, Wayne Michael
- Date: 2011
- Subjects: Ecosystem services -- South Africa -- Eastern Cape Ecology -- Economic aspects -- South Africa -- Eastern Cape Environmental economics -- South Africa -- Eastern Cape Water-supply -- South Africa -- Eastern Cape Water-supply -- South Africa -- Eastern Cape -- Management Water resources development -- South Africa -- Eastern Cape Nature conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:742 , http://hdl.handle.net/10962/d1003862
- Description: Cities must go further and further away to find new, more costly sources of water for human consumption while industries and agriculture continue to compete for increasingly scarce water resources. This may already be seen occurring within the Nelson Mandela Bay Metro where the severe drought being experienced during the past 18 months has severely depleted water supply dams. One of the main supply dams to the Nelson Mandela Bay Municipality is situated within the Baviaanskloof Nature Reserve and World Heritage Site. The potential of funding the Baviaanskloof Nature Reserve and World Heritage Site with payments for ecosystem services (water) obtained for water services supplied to the Nelson Mandela Bay Municipalities and agriculture in the Gamtoos River Valley will ensure financial sustainable for the Baviaanskloof Nature Reserve and World Heritage Site in the long term. This ability to become financially independent and generate its own income will place the Baviaanskloof Nature Reserve and World Heritage Site in a unique position within the conservation community in South Africa as only a very few protected areas are self sustaining through payment for an ecosystem service.
- Full Text:
- Date Issued: 2011
Towards a critical understanding of media assistance for "new media" development
- Authors: Mathurine, Jude
- Date: 2011
- Subjects: Mass media -- Technological innovations , Mass media -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3459 , http://hdl.handle.net/10962/d1002914 , Mass media -- Technological innovations , Mass media -- Political aspects
- Description: The field of media assistance has grown ever more complex with the inclusion of ‘new media’ networks, channels, tools and practices (such as the Internet, satellite television, mobile devices, social media and citizen journalism) to the media development mix. Adding to the ferment is the increasing convergence between the formerly discrete terrains of ICT for development, media for development and (mass) media development. Much of the discussion regarding the utility and objectives of media development in general and ‘new media’ in particular has been viewed through a modernist and techno-determinist prism which offers a limited ideological view of media development and its objects and consequently, a limited set of communication approaches and strategies. This study contextualises the assumptions of media development historically and critically, with particular focus on new media’s roles and relationships with the media environment, and its objectives democratisation and development. Through the application of literature, theory and various research studies, this thesis establishes a broader view of new media’s role and diverse consequences for media development, democracy and development. The study recommends greater collaboration, contextual research and theorisation of media development and new media as part of mixed media systems and cognisant of the multi-dimensional natures of its objects of democracy and development. One implication is the need for professionalisation of the media development and media assistance sector. In relation to the influences of new media on media use and the media as an institution, it motivates the need to address digital divides and emphasise the sustainability of the practice of journalism.
- Full Text:
- Date Issued: 2011
- Authors: Mathurine, Jude
- Date: 2011
- Subjects: Mass media -- Technological innovations , Mass media -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3459 , http://hdl.handle.net/10962/d1002914 , Mass media -- Technological innovations , Mass media -- Political aspects
- Description: The field of media assistance has grown ever more complex with the inclusion of ‘new media’ networks, channels, tools and practices (such as the Internet, satellite television, mobile devices, social media and citizen journalism) to the media development mix. Adding to the ferment is the increasing convergence between the formerly discrete terrains of ICT for development, media for development and (mass) media development. Much of the discussion regarding the utility and objectives of media development in general and ‘new media’ in particular has been viewed through a modernist and techno-determinist prism which offers a limited ideological view of media development and its objects and consequently, a limited set of communication approaches and strategies. This study contextualises the assumptions of media development historically and critically, with particular focus on new media’s roles and relationships with the media environment, and its objectives democratisation and development. Through the application of literature, theory and various research studies, this thesis establishes a broader view of new media’s role and diverse consequences for media development, democracy and development. The study recommends greater collaboration, contextual research and theorisation of media development and new media as part of mixed media systems and cognisant of the multi-dimensional natures of its objects of democracy and development. One implication is the need for professionalisation of the media development and media assistance sector. In relation to the influences of new media on media use and the media as an institution, it motivates the need to address digital divides and emphasise the sustainability of the practice of journalism.
- Full Text:
- Date Issued: 2011