Electrocatalysis of oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione by adsorbed and electrodeposited cobalt tetra phenoxypyrrole and tetra ethoxythiophene substituted phthalocyanines
- Sehlotho, Nthapo, Nyokong, Tebello, Zagal, Jose H, Bedioui, Fethi
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
Electrocatalytic oxidation of thiocyanate, L-cysteine and 2-mercaptoethanol by self-assembled monolayer of cobalt tetraethoxy thiophene phthalocyanine
- Sehlotho, Nthapo, Nyokong, Tebello
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283814 , vital:55993 , xlink:href="https://doi.org/10.1016/j.electacta.2005.12.024"
- Description: Catalytic activity of a self-assembled monolayer (SAM) of cobalt tetra ethoxythiophene phthalocyanine (CoTEThPc-SAM) complex towards oxidation of thiocyanate (SCN−), L-cysteine (CYS) and 2-mercaptoethanol (2-ME) is reported. The oxidation of thiocyanate occurs via a two electron transfer, whereas L-cysteine and 2-ME require 1 electron. The oxidation of thiocyanate is catalysed by ring based processes, while L-cysteine is catalysed by both CoIII/CoII process and by ring based processes. 2-ME is catalysed by CoIII/CoII process. The oxidation of thiocyanate on CoTEThPc was performed in acid media instead of basic media commonly employed. The reaction order was found to be unity for all the analytes, showing that only one molecule of analyte interacts with one molecule of the catalyst during the rate determining step.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283814 , vital:55993 , xlink:href="https://doi.org/10.1016/j.electacta.2005.12.024"
- Description: Catalytic activity of a self-assembled monolayer (SAM) of cobalt tetra ethoxythiophene phthalocyanine (CoTEThPc-SAM) complex towards oxidation of thiocyanate (SCN−), L-cysteine (CYS) and 2-mercaptoethanol (2-ME) is reported. The oxidation of thiocyanate occurs via a two electron transfer, whereas L-cysteine and 2-ME require 1 electron. The oxidation of thiocyanate is catalysed by ring based processes, while L-cysteine is catalysed by both CoIII/CoII process and by ring based processes. 2-ME is catalysed by CoIII/CoII process. The oxidation of thiocyanate on CoTEThPc was performed in acid media instead of basic media commonly employed. The reaction order was found to be unity for all the analytes, showing that only one molecule of analyte interacts with one molecule of the catalyst during the rate determining step.
- Full Text:
- Date Issued: 2006
Effects of ring substituents on electrocatalytic activity of manganese phthalocyanines towards the reduction of molecular oxygen
- Sehlotho, Nthapo, Nyokong, Tebello
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6594 , http://hdl.handle.net/10962/d1004343
- Description: Reduction of oxygen electrocatalyzed by adsorbed films of manganese phthalocyanine complexes is reported. The complexes studied were: manganese phthalocyanine (MnPc, 1); manganese tetraamino phthalocyanine (MnTAPc, 2); manganese tetrapentoxy pyrrole phthalocyanine (MnTPePyrPc, 3); manganese tetra phenoxy pyrrole phthalocyanine (MnTPPyrPc, 4); manganese tetra mercaptopyrimidine phthalocyanine (MnTMPyPc, 5) and manganese tetra ethoxy thiophene phthalocyanine (MnTETPc, 6). The reaction was conducted in buffer solutions of pH range 1–12. Rotating disk electrode voltammetry revealed two electron reduction in acidic and slightly alkaline media due to the formation of hydrogen peroxide. In highly basic media, water is the major product formed via four electron transfer. The reaction was found to be first order in the diffusing analyte oxygen.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6594 , http://hdl.handle.net/10962/d1004343
- Description: Reduction of oxygen electrocatalyzed by adsorbed films of manganese phthalocyanine complexes is reported. The complexes studied were: manganese phthalocyanine (MnPc, 1); manganese tetraamino phthalocyanine (MnTAPc, 2); manganese tetrapentoxy pyrrole phthalocyanine (MnTPePyrPc, 3); manganese tetra phenoxy pyrrole phthalocyanine (MnTPPyrPc, 4); manganese tetra mercaptopyrimidine phthalocyanine (MnTMPyPc, 5) and manganese tetra ethoxy thiophene phthalocyanine (MnTETPc, 6). The reaction was conducted in buffer solutions of pH range 1–12. Rotating disk electrode voltammetry revealed two electron reduction in acidic and slightly alkaline media due to the formation of hydrogen peroxide. In highly basic media, water is the major product formed via four electron transfer. The reaction was found to be first order in the diffusing analyte oxygen.
- Full Text:
- Date Issued: 2006
The application of integrated environmental management to improve storm water quality and reduce marine pollution at Jeffreys Bay (South Africa)
- Authors: Seebach, Rudi Dieter
- Date: 2006
- Subjects: Marine pollution -- South Africa -- Jeffreys Bay , Storm sewers -- South Africa -- Jeffreys Bay , Marine ecology -- South Africa -- Jeffreys Bay , Environmental management -- South Africa -- Jeffreys Bay , Environmental risk assessment -- South Africa -- Jeffreys Bay , Community development -- South Africa -- Jeffreys Bay , Sustainable development -- South Africa -- Jeffreys Bay , Sewage disposal -- South Africa -- Jeffreys Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4738 , http://hdl.handle.net/10962/d1005287 , Marine pollution -- South Africa -- Jeffreys Bay , Storm sewers -- South Africa -- Jeffreys Bay , Marine ecology -- South Africa -- Jeffreys Bay , Environmental management -- South Africa -- Jeffreys Bay , Environmental risk assessment -- South Africa -- Jeffreys Bay , Community development -- South Africa -- Jeffreys Bay , Sustainable development -- South Africa -- Jeffreys Bay , Sewage disposal -- South Africa -- Jeffreys Bay
- Description: It is projected that by 2025 three-quarters of the world’s population will live in the coastal zone. This is an alarming statistic, with a consequently significant impact on small coastal towns and the adjacent marine environments. Developing communities within the coastal zone of South Africa have proved to be a significant pollution source of storm water. Studies have shown that storm water that is deposited in the ocean will be trapped in the near shore marine environment causing poor seawater quality over a large distance. Furthermore, this can pose a significant threat to the health of recreational users and important marine ecosystems. In Jeffreys Bay storm water quality is thought to pose a threat to the maintenance of the international Blue Flag status for its beach. The aim of the current project was to investigate the main sources of storm water and subsequent marine pollution at Jeffreys Bay and to develop an appropriate management strategy using the integrated environmental management framework. In order to achieve this objective, it was also necessary to determine the current quality of water at various points within the catchment and near shore marine environment. Even though the storm water was found to be severely contaminated no evidence existed for a negative impact on the marine environment. None the less, a precautionary approach was adopted and a risk assessment employed in order to consider potential impacts on the marine and aquatic environment, human health and socio-economic welfare within the town. Significant sources of storm water contamination included grey water, domestic solid waste disposal and informal ablution. These significant aspects were investigated further and it was found that solid waste management in the catchment was poor with significant quantities of waste, primarily (76%) from domestic sources, being disposed of illegally. A study of sanitation management showed inadequacies where up to 58% of the residents from the informal settlements disposed of their grey water into open spaces. The ratio of residents to toilets in these areas was 28:1, therefore supporting the outcome of the risk assessment. Due to the fact that all the significant aspects were related to anthropogenic waste, an integrated waste management plan (IWMP) was developed that would not only facilitate the reduction of pollution of storm water, but would also allow for sustainable community-based development.
- Full Text:
- Date Issued: 2006
- Authors: Seebach, Rudi Dieter
- Date: 2006
- Subjects: Marine pollution -- South Africa -- Jeffreys Bay , Storm sewers -- South Africa -- Jeffreys Bay , Marine ecology -- South Africa -- Jeffreys Bay , Environmental management -- South Africa -- Jeffreys Bay , Environmental risk assessment -- South Africa -- Jeffreys Bay , Community development -- South Africa -- Jeffreys Bay , Sustainable development -- South Africa -- Jeffreys Bay , Sewage disposal -- South Africa -- Jeffreys Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4738 , http://hdl.handle.net/10962/d1005287 , Marine pollution -- South Africa -- Jeffreys Bay , Storm sewers -- South Africa -- Jeffreys Bay , Marine ecology -- South Africa -- Jeffreys Bay , Environmental management -- South Africa -- Jeffreys Bay , Environmental risk assessment -- South Africa -- Jeffreys Bay , Community development -- South Africa -- Jeffreys Bay , Sustainable development -- South Africa -- Jeffreys Bay , Sewage disposal -- South Africa -- Jeffreys Bay
- Description: It is projected that by 2025 three-quarters of the world’s population will live in the coastal zone. This is an alarming statistic, with a consequently significant impact on small coastal towns and the adjacent marine environments. Developing communities within the coastal zone of South Africa have proved to be a significant pollution source of storm water. Studies have shown that storm water that is deposited in the ocean will be trapped in the near shore marine environment causing poor seawater quality over a large distance. Furthermore, this can pose a significant threat to the health of recreational users and important marine ecosystems. In Jeffreys Bay storm water quality is thought to pose a threat to the maintenance of the international Blue Flag status for its beach. The aim of the current project was to investigate the main sources of storm water and subsequent marine pollution at Jeffreys Bay and to develop an appropriate management strategy using the integrated environmental management framework. In order to achieve this objective, it was also necessary to determine the current quality of water at various points within the catchment and near shore marine environment. Even though the storm water was found to be severely contaminated no evidence existed for a negative impact on the marine environment. None the less, a precautionary approach was adopted and a risk assessment employed in order to consider potential impacts on the marine and aquatic environment, human health and socio-economic welfare within the town. Significant sources of storm water contamination included grey water, domestic solid waste disposal and informal ablution. These significant aspects were investigated further and it was found that solid waste management in the catchment was poor with significant quantities of waste, primarily (76%) from domestic sources, being disposed of illegally. A study of sanitation management showed inadequacies where up to 58% of the residents from the informal settlements disposed of their grey water into open spaces. The ratio of residents to toilets in these areas was 28:1, therefore supporting the outcome of the risk assessment. Due to the fact that all the significant aspects were related to anthropogenic waste, an integrated waste management plan (IWMP) was developed that would not only facilitate the reduction of pollution of storm water, but would also allow for sustainable community-based development.
- Full Text:
- Date Issued: 2006
A Geographic Information System for the African Coelacanth Ecosystem Programme
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7129 , http://hdl.handle.net/10962/d1010639
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7129 , http://hdl.handle.net/10962/d1010639
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
A Geographic Information System for the African Coelacanth Ecosystem Programme
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7159 , http://hdl.handle.net/10962/d1011886
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7159 , http://hdl.handle.net/10962/d1011886
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
Atlas of Southern African freshwater fishes
- Scott, L E P, Skelton, P H, Booth, A J, Verheust, L, Dooley, J, Harris, R
- Authors: Scott, L E P , Skelton, P H , Booth, A J , Verheust, L , Dooley, J , Harris, R
- Date: 2006
- Subjects: Freshwater fishes -- South Africa , Freshwater fishes -- Africa, Southern , Freshwater fishes -- Africa, Southern -- Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/199097 , vital:46068
- Description: Worldwide concern over the loss of biological diversity during the past decade has provided the impetus for the development of biodiversity databases and biological atlas projects in order to make information accessible. This Geographic Information Systems-based Atlas of Southern African Freshwater Fishes is the first of its kind for fishes in Africa and, as such, can be seen as contributing towards this global trend of consolidation and refining of biodiversity information. The technological advances made in computing systems over the past decade have facilitated the extraction and utilisation of much of the untapped information in museum collections. The size of most natural history collections had tended to prohibit any comprehensive applied use of the specimens on a large scale, but the computerisation of these collections has proved to be an invaluable tool to systematists, taxonomists and ecologists, by allowing faster and more efficient access to specimen record data of interest. With the automation of many biological databases, public attention has been brought to their potential contribution to biodiversity studies and conservation efforts around the world. The application of Geographic Information Systems (GIS) in the field of southern African ichthyology and freshwater fisheries management has been limited, until now, by the lack of good-quality, comprehensive data sets, adequate budgets and GIS skills. Sophisticated investigations of fish distributions for conservation and management purposes need a powerful computing platform. This is realised in the Atlas of Southern African Freshwater Fishes, which has been tested and used for biogeographic analysis in the southern African region. The atlas was established using specimen records from nineteen museum collections, and currently contains 35145 geo-referenced specimen records, collected between 1885 and 2000 in eleven countries of southern Africa, which represent 254 fish species from 37 families. The Atlas of Southern African Freshwater Fishes was developed with the objective of being a dynamic, powerful information system. It has been constructed to allow the import of additional information at any stage, and it is designed to be as accessible and as user-friendly as current technology allows. This Atlas is the product of the successful integration of fish distributional information with other spatial data layers to provide a new tool for the study of freshwater fish in southern Africa.
- Full Text:
- Date Issued: 2006
- Authors: Scott, L E P , Skelton, P H , Booth, A J , Verheust, L , Dooley, J , Harris, R
- Date: 2006
- Subjects: Freshwater fishes -- South Africa , Freshwater fishes -- Africa, Southern , Freshwater fishes -- Africa, Southern -- Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/199097 , vital:46068
- Description: Worldwide concern over the loss of biological diversity during the past decade has provided the impetus for the development of biodiversity databases and biological atlas projects in order to make information accessible. This Geographic Information Systems-based Atlas of Southern African Freshwater Fishes is the first of its kind for fishes in Africa and, as such, can be seen as contributing towards this global trend of consolidation and refining of biodiversity information. The technological advances made in computing systems over the past decade have facilitated the extraction and utilisation of much of the untapped information in museum collections. The size of most natural history collections had tended to prohibit any comprehensive applied use of the specimens on a large scale, but the computerisation of these collections has proved to be an invaluable tool to systematists, taxonomists and ecologists, by allowing faster and more efficient access to specimen record data of interest. With the automation of many biological databases, public attention has been brought to their potential contribution to biodiversity studies and conservation efforts around the world. The application of Geographic Information Systems (GIS) in the field of southern African ichthyology and freshwater fisheries management has been limited, until now, by the lack of good-quality, comprehensive data sets, adequate budgets and GIS skills. Sophisticated investigations of fish distributions for conservation and management purposes need a powerful computing platform. This is realised in the Atlas of Southern African Freshwater Fishes, which has been tested and used for biogeographic analysis in the southern African region. The atlas was established using specimen records from nineteen museum collections, and currently contains 35145 geo-referenced specimen records, collected between 1885 and 2000 in eleven countries of southern Africa, which represent 254 fish species from 37 families. The Atlas of Southern African Freshwater Fishes was developed with the objective of being a dynamic, powerful information system. It has been constructed to allow the import of additional information at any stage, and it is designed to be as accessible and as user-friendly as current technology allows. This Atlas is the product of the successful integration of fish distributional information with other spatial data layers to provide a new tool for the study of freshwater fish in southern Africa.
- Full Text:
- Date Issued: 2006
Exploring the practical adequacy of the normative framework guiding South Africa’s National Curriculum Statement
- Schudel, Ingrid, Lotz-Sisitka, Heila
- Authors: Schudel, Ingrid , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391193 , vital:68630 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
- Authors: Schudel, Ingrid , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391193 , vital:68630 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
‘Exploring the practical adequacy of the human rights, social justice, inclusivity and healthy environment policy discourse in South Africa’s National Curriculum Statement’
- Schudel, Ingrid, Lotz-Sisitka, Heila
- Authors: Schudel, Ingrid , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391180 , vital:68629 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
- Authors: Schudel, Ingrid , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391180 , vital:68629 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
Synthesis of triprenylated toluquinone and toluhydroquinone metabolites from a marine-derived Penicillium fungus
- Scheepers, Brent A, Klein, Rosalyn, Davies-Coleman, Michael T
- Authors: Scheepers, Brent A , Klein, Rosalyn , Davies-Coleman, Michael T
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6592 , http://hdl.handle.net/10962/d1004341
- Description: Two triprenylated toluquinone and toluhydroquinone marine fungal metabolites, 5-methyl-2-[(2′E,6′E)-3′,7′,11′-trimethyl-2′,6′,10′-dodecatrienyl]-2,5-cyclohexadiene-1,4-dione and 5-methyl-2-[(2′E,6′E)-3,7,11-trimethyl-2′,6′,10′-dodecatrienyl]-1,4-benzenediol, were synthesized in four and five steps, respectively, from 2-methyl-1,4-benzoquinone. The synthesis extends the applicability of the oxidative ether cleavage of hydroquinone dimethyl ethers with argentic oxide under acidic conditions to include the oxidative demethylation of polyprenylated-1,4-dimethoxy-toluhydroquinones with a quantitative survival of the oxidation- and acid-sensitive polyprenyl side chain. Graphical abstract: Marine fungal metabolites 1 and 2 were synthesized from 2-methyl-1,4-benzoquinone in four and five steps, respectively. [For graphic image see full-text version]
- Full Text:
- Date Issued: 2006
- Authors: Scheepers, Brent A , Klein, Rosalyn , Davies-Coleman, Michael T
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6592 , http://hdl.handle.net/10962/d1004341
- Description: Two triprenylated toluquinone and toluhydroquinone marine fungal metabolites, 5-methyl-2-[(2′E,6′E)-3′,7′,11′-trimethyl-2′,6′,10′-dodecatrienyl]-2,5-cyclohexadiene-1,4-dione and 5-methyl-2-[(2′E,6′E)-3,7,11-trimethyl-2′,6′,10′-dodecatrienyl]-1,4-benzenediol, were synthesized in four and five steps, respectively, from 2-methyl-1,4-benzoquinone. The synthesis extends the applicability of the oxidative ether cleavage of hydroquinone dimethyl ethers with argentic oxide under acidic conditions to include the oxidative demethylation of polyprenylated-1,4-dimethoxy-toluhydroquinones with a quantitative survival of the oxidation- and acid-sensitive polyprenyl side chain. Graphical abstract: Marine fungal metabolites 1 and 2 were synthesized from 2-methyl-1,4-benzoquinone in four and five steps, respectively. [For graphic image see full-text version]
- Full Text:
- Date Issued: 2006
A holistic approach to consumption analysis in the popular music market
- Authors: Scheckter, Jonathan
- Date: 2006
- Subjects: Consumption (Economics) -- Moral and ethical aspects , Music trade -- South Africa , Popular music -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:981 , http://hdl.handle.net/10962/d1002715 , Consumption (Economics) -- Moral and ethical aspects , Music trade -- South Africa , Popular music -- Economic aspects -- South Africa
- Description: This thesis seeks to gain a holistic understanding of consumption issues in the popular music market, such that it needs to account for the influence of 1) technological factors, 2) institutional factors, 3) cultural factors, and 4) an ontological aspect; as these are identified to be the most prominent aspects in the literature on the market. While there is a bourgeoning literature on the market, there has been little formal attempt to link such issues in a comprehensive fashion. The methodology applied provides a critique of the literature on specific consumption theories which have apparent pertinence to the music market. Each of the sociological, psychological, and economic theories (neoclassical and radical) is found to be too generalized to provide such an understanding, in that many issues concerning the music market would need to be eschewed if these theories were to be applied in an orthodox fashion. Moreover, the theories tend to point towards each other for the possibility of a credible, holistic consumption analysis. The most useful and all-encompassing consumption theory reviewed is the systems of provision approach advanced by Fine and Leopold (1993), in that the approach aims to be sensitive to the difference between commodities in terms of the economic and social processes and structures by which they become commodities, and thus it can allow one to consider adequately the four requirements identified above for a holistic understanding of the market. This approach is then applied to the western music market with the aim of 1) testing the approach identified, and 2) making a specific comment of the market. The market is found to be characterized historically by three distinct periods, each with distinct systems of provision (i.e. each with the four factors identified above relating to each other in a certain manner). It is proposed that preference formations in the final period identified have been institutionalized to a large extent, and there is a low probability of change occurring. The systems of provision approach is argued to be beneficial in highlighting which aspects of the existing consumption theories are relevant to the market at a point in time, and to what extent. Thus the richness of the approach stems from its ability to gain a holistic understanding, and to identify theoretical discussion topics, such as those concerning political economy. The approach is then applied to the South African music market, using the same historical methodology, in conjunction with current empirical evidence from the market. Doing this allows one to test the generality of the systems of provision approach, and to attempt to make a comment on the South African market. The techniques for obtaining empirical evidence are argued to be sound, but resource constraints prevented the research from reflecting a holistic view of the market. Nonetheless, a rich perspective is provided from interviews with prominent agents in the market, and thus the chapter is argued to provide the beginning of an understanding of preference formations in the South African music market, in which little research has been conducted (Stella, 2005).
- Full Text:
- Date Issued: 2006
- Authors: Scheckter, Jonathan
- Date: 2006
- Subjects: Consumption (Economics) -- Moral and ethical aspects , Music trade -- South Africa , Popular music -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:981 , http://hdl.handle.net/10962/d1002715 , Consumption (Economics) -- Moral and ethical aspects , Music trade -- South Africa , Popular music -- Economic aspects -- South Africa
- Description: This thesis seeks to gain a holistic understanding of consumption issues in the popular music market, such that it needs to account for the influence of 1) technological factors, 2) institutional factors, 3) cultural factors, and 4) an ontological aspect; as these are identified to be the most prominent aspects in the literature on the market. While there is a bourgeoning literature on the market, there has been little formal attempt to link such issues in a comprehensive fashion. The methodology applied provides a critique of the literature on specific consumption theories which have apparent pertinence to the music market. Each of the sociological, psychological, and economic theories (neoclassical and radical) is found to be too generalized to provide such an understanding, in that many issues concerning the music market would need to be eschewed if these theories were to be applied in an orthodox fashion. Moreover, the theories tend to point towards each other for the possibility of a credible, holistic consumption analysis. The most useful and all-encompassing consumption theory reviewed is the systems of provision approach advanced by Fine and Leopold (1993), in that the approach aims to be sensitive to the difference between commodities in terms of the economic and social processes and structures by which they become commodities, and thus it can allow one to consider adequately the four requirements identified above for a holistic understanding of the market. This approach is then applied to the western music market with the aim of 1) testing the approach identified, and 2) making a specific comment of the market. The market is found to be characterized historically by three distinct periods, each with distinct systems of provision (i.e. each with the four factors identified above relating to each other in a certain manner). It is proposed that preference formations in the final period identified have been institutionalized to a large extent, and there is a low probability of change occurring. The systems of provision approach is argued to be beneficial in highlighting which aspects of the existing consumption theories are relevant to the market at a point in time, and to what extent. Thus the richness of the approach stems from its ability to gain a holistic understanding, and to identify theoretical discussion topics, such as those concerning political economy. The approach is then applied to the South African music market, using the same historical methodology, in conjunction with current empirical evidence from the market. Doing this allows one to test the generality of the systems of provision approach, and to attempt to make a comment on the South African market. The techniques for obtaining empirical evidence are argued to be sound, but resource constraints prevented the research from reflecting a holistic view of the market. Nonetheless, a rich perspective is provided from interviews with prominent agents in the market, and thus the chapter is argued to provide the beginning of an understanding of preference formations in the South African music market, in which little research has been conducted (Stella, 2005).
- Full Text:
- Date Issued: 2006
Estimation of small reservoir storage capacities in Limpopo River Basin using geographical information systems (GIS) and remotely sensed surface areas: case of Mzingwane catchment
- Sawunyama, Tendai, Senzanje, J, Mhizha, A
- Authors: Sawunyama, Tendai , Senzanje, J , Mhizha, A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7077 , http://hdl.handle.net/10962/d1009741
- Description: The current interest in small reservoirs stems mainly from their utilization for domestic use, livestock watering, fishing and irrigation. Rarely were small reservoirs considered in the water resources system even though they are important in water resource planning and management. The main limitation being lack of knowledge on small reservoir capacities, for the methodologies used to quantify physical parameters of reservoirs are costly, time consuming and laborious. To address this challenge an attempt has been made in this study to estimate small reservoir storage capacities using remotely sensed surface areas. A field study on 12 small reservoirs was carried out in Mzingwane catchment in Limpopo River Basin; Zimbabwe. The depths of water accompanied with their coordinates were measured; from which area and capacity were calculated for each reservoir using geographical information system based on data acquired from the field and that from satellite images. The output data was compared and a linear regression analysis was carried out to establish a power relationship between surface area and storage capacity of small reservoirs. The Pearson correlation analysis at 95% confidence interval indicated that the variances of the two surface areas (field area and image area) were not significantly different (p < 0.05). The findings from linear regression analysis (log capacity–log area) show that there exist a power relationship between remotely sensed surface areas (m^2) and storage capacities of reservoirs (m^3), with 95% variation of the storage capacity being explained by surface areas. The relationship can be used as a tool in decision-making processes in integrated water resources planning and management in the river basin. The applicability of the relationship to other catchments requires further research as well as investigating the impacts of small reservoirs in water resources available in the river basin by carrying out a hydrological modelling of the catchment.
- Full Text:
- Date Issued: 2006
- Authors: Sawunyama, Tendai , Senzanje, J , Mhizha, A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7077 , http://hdl.handle.net/10962/d1009741
- Description: The current interest in small reservoirs stems mainly from their utilization for domestic use, livestock watering, fishing and irrigation. Rarely were small reservoirs considered in the water resources system even though they are important in water resource planning and management. The main limitation being lack of knowledge on small reservoir capacities, for the methodologies used to quantify physical parameters of reservoirs are costly, time consuming and laborious. To address this challenge an attempt has been made in this study to estimate small reservoir storage capacities using remotely sensed surface areas. A field study on 12 small reservoirs was carried out in Mzingwane catchment in Limpopo River Basin; Zimbabwe. The depths of water accompanied with their coordinates were measured; from which area and capacity were calculated for each reservoir using geographical information system based on data acquired from the field and that from satellite images. The output data was compared and a linear regression analysis was carried out to establish a power relationship between surface area and storage capacity of small reservoirs. The Pearson correlation analysis at 95% confidence interval indicated that the variances of the two surface areas (field area and image area) were not significantly different (p < 0.05). The findings from linear regression analysis (log capacity–log area) show that there exist a power relationship between remotely sensed surface areas (m^2) and storage capacities of reservoirs (m^3), with 95% variation of the storage capacity being explained by surface areas. The relationship can be used as a tool in decision-making processes in integrated water resources planning and management in the river basin. The applicability of the relationship to other catchments requires further research as well as investigating the impacts of small reservoirs in water resources available in the river basin by carrying out a hydrological modelling of the catchment.
- Full Text:
- Date Issued: 2006
The impact of media commercialization on public service broadcasting : the case of Radio Zimbabwe after the adoption of the Commercialisation Act (No 26) of 2001
- Authors: Saurombe, Memory
- Date: 2006
- Subjects: Zimbabwe Broadcasting Corporation , Broadcasting -- Zimbabwe , Mass media -- Social aspects -- Zimbabwe , Public broadcasting -- Zimbabwe -- History -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8410 , http://hdl.handle.net/10948/601 , http://hdl.handle.net/10948/d1011671 , Zimbabwe Broadcasting Corporation , Broadcasting -- Zimbabwe , Mass media -- Social aspects -- Zimbabwe , Public broadcasting -- Zimbabwe -- History -- 20th century
- Description: Cultural and educational functions of public service broadcasting come at a fortuitous time, as the changing environment of broadcasting is on various agendas. At the heart of this is the question of the present and future status of public service broadcasting. Major changes have taken place in the political economy of the media and the world economy at large, technological advancement has resulted in privatization and commercialization of the media. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study will examine the extent to which the adoption of the Commercialization Act (No 26) of 2001 in Zimbabwe has affected Radio Zimbabwe’s role as a public broadcaster. The study is based on the hypothesis that with the adoption of the Commercialization Act, Radio Zimbabwe is no longer playing its public service role effectively. The current nature of programming at Radio Zimbabwe as the research hopes to show will highlight tremendous changes towards a commercial logic. The study uses a combination of document analysis, secondary literature and qualitative interviews.
- Full Text:
- Date Issued: 2006
- Authors: Saurombe, Memory
- Date: 2006
- Subjects: Zimbabwe Broadcasting Corporation , Broadcasting -- Zimbabwe , Mass media -- Social aspects -- Zimbabwe , Public broadcasting -- Zimbabwe -- History -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8410 , http://hdl.handle.net/10948/601 , http://hdl.handle.net/10948/d1011671 , Zimbabwe Broadcasting Corporation , Broadcasting -- Zimbabwe , Mass media -- Social aspects -- Zimbabwe , Public broadcasting -- Zimbabwe -- History -- 20th century
- Description: Cultural and educational functions of public service broadcasting come at a fortuitous time, as the changing environment of broadcasting is on various agendas. At the heart of this is the question of the present and future status of public service broadcasting. Major changes have taken place in the political economy of the media and the world economy at large, technological advancement has resulted in privatization and commercialization of the media. In most societies where these changes have taken place, public service broadcasting has been threatened by the rapid rise of commercial institutions, resulting in stiff competition for audiences. This study will examine the extent to which the adoption of the Commercialization Act (No 26) of 2001 in Zimbabwe has affected Radio Zimbabwe’s role as a public broadcaster. The study is based on the hypothesis that with the adoption of the Commercialization Act, Radio Zimbabwe is no longer playing its public service role effectively. The current nature of programming at Radio Zimbabwe as the research hopes to show will highlight tremendous changes towards a commercial logic. The study uses a combination of document analysis, secondary literature and qualitative interviews.
- Full Text:
- Date Issued: 2006
A precarious balance: consequences of Zimbabwe's fast-track land reform
- Authors: Sarimana, Ashley
- Date: 2006
- Subjects: Land reform -- Zimbabwe , Land use -- Government policy -- Zimbabwe , Land settlement -- Government policy -- Zimbabwe , Farms, Large -- Zimbabwe , Agriculture and state -- Zimbabwe , Agricultural laborers -- Zimbabwe , Zimbabwe -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3348 , http://hdl.handle.net/10962/d1006198 , Land reform -- Zimbabwe , Land use -- Government policy -- Zimbabwe , Land settlement -- Government policy -- Zimbabwe , Farms, Large -- Zimbabwe , Agriculture and state -- Zimbabwe , Agricultural laborers -- Zimbabwe , Zimbabwe -- Economic conditions
- Description: This thesis is a detailed account of Zimbabwe's controversial fast-track land reform programme. Zimbabwe's land reform history has been discussed extensively, with a focus on land redistribution. The fast-track land reform programme transferred eleven million hectares of land from 4 000 white commercial farmers to 51 543 landless peasant families. The thesis begins by offering some land reform theories and gives an overview of the land question in Southern Africa. This is followed by a discussion of Zimbabwe's land question from a historical perspective. Next is a periodised account of the successes and failures of land reform attempts made by the Zimbabwean government from independence in 1980 to 1998 when the fast-track land reform programme was conceived. Zimbabwe's political and economic situation at this time is significant. The context for fast-track land reform includes a discussion about the national question in Zimbabwe and the deteriorating status of white citizenship; the rise of Zimbabwe's liberation war veterans as a formidable force and the formation of the Movement for Democratic Change as a strong political party that was challenging, among others, the dominance of the ruling Zanu-PF party and its policies. The blueprint for fast-track land reform is discussed in order to contrast it to how the reform unfolded in practice. In this regard, the response of the international community to the violence and lawlessness that characterised fast-track land reform is worth mentioning, especially since it has bearing on how Zimbabweans are trying to cope with life in a radically altered physical and social environment, following the land reform exercise. The consequences of fast-track land reform are analysed in terms of development and the plight of Zimbabwe's farm workers; the internal displacement of hundreds of thousands of farm workers, white commercial farmers and others in Zimbabwe's countryside and whether or not fast-track land reform beneficiaries can successfully engage in agriculture to improve their standard of living. The Vumba and Burma Valley case study is illustrative of how fasttrack land reform was implemented and its socio-economic impact on Zimbabwe's poor and marginalised groups, for instance, female farm workers. The case study offers valuable insights about the survival strategies that ordinary people affected by the land reform exercise are adopting in order to cope with their new circumstances. Data was gathered from a focus group discussion (pilot study), in-depth semi-structured interviews and observation on three farms, as well as interviews with a few government officials, government documents and newspaper reports. The study is useful to countries that are planning or already implementing land reform, for example, South Africa.
- Full Text:
- Date Issued: 2006
- Authors: Sarimana, Ashley
- Date: 2006
- Subjects: Land reform -- Zimbabwe , Land use -- Government policy -- Zimbabwe , Land settlement -- Government policy -- Zimbabwe , Farms, Large -- Zimbabwe , Agriculture and state -- Zimbabwe , Agricultural laborers -- Zimbabwe , Zimbabwe -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3348 , http://hdl.handle.net/10962/d1006198 , Land reform -- Zimbabwe , Land use -- Government policy -- Zimbabwe , Land settlement -- Government policy -- Zimbabwe , Farms, Large -- Zimbabwe , Agriculture and state -- Zimbabwe , Agricultural laborers -- Zimbabwe , Zimbabwe -- Economic conditions
- Description: This thesis is a detailed account of Zimbabwe's controversial fast-track land reform programme. Zimbabwe's land reform history has been discussed extensively, with a focus on land redistribution. The fast-track land reform programme transferred eleven million hectares of land from 4 000 white commercial farmers to 51 543 landless peasant families. The thesis begins by offering some land reform theories and gives an overview of the land question in Southern Africa. This is followed by a discussion of Zimbabwe's land question from a historical perspective. Next is a periodised account of the successes and failures of land reform attempts made by the Zimbabwean government from independence in 1980 to 1998 when the fast-track land reform programme was conceived. Zimbabwe's political and economic situation at this time is significant. The context for fast-track land reform includes a discussion about the national question in Zimbabwe and the deteriorating status of white citizenship; the rise of Zimbabwe's liberation war veterans as a formidable force and the formation of the Movement for Democratic Change as a strong political party that was challenging, among others, the dominance of the ruling Zanu-PF party and its policies. The blueprint for fast-track land reform is discussed in order to contrast it to how the reform unfolded in practice. In this regard, the response of the international community to the violence and lawlessness that characterised fast-track land reform is worth mentioning, especially since it has bearing on how Zimbabweans are trying to cope with life in a radically altered physical and social environment, following the land reform exercise. The consequences of fast-track land reform are analysed in terms of development and the plight of Zimbabwe's farm workers; the internal displacement of hundreds of thousands of farm workers, white commercial farmers and others in Zimbabwe's countryside and whether or not fast-track land reform beneficiaries can successfully engage in agriculture to improve their standard of living. The Vumba and Burma Valley case study is illustrative of how fasttrack land reform was implemented and its socio-economic impact on Zimbabwe's poor and marginalised groups, for instance, female farm workers. The case study offers valuable insights about the survival strategies that ordinary people affected by the land reform exercise are adopting in order to cope with their new circumstances. Data was gathered from a focus group discussion (pilot study), in-depth semi-structured interviews and observation on three farms, as well as interviews with a few government officials, government documents and newspaper reports. The study is useful to countries that are planning or already implementing land reform, for example, South Africa.
- Full Text:
- Date Issued: 2006
Strategy formulation, alignment and implementation to ensure that Behr is competitive internationally : a case study
- Authors: Samuels, Donald
- Date: 2006
- Subjects: Automobile industry and trade -- South Africa , Competition, International , Globalization , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8761 , http://hdl.handle.net/10948/600 , http://hdl.handle.net/10948/d1011685 , Automobile industry and trade -- South Africa , Competition, International , Globalization , Strategic planning
- Description: South Africa’s transition to democracy in 1994 has heralded a re-entry into the global economy. This has meant that for the first time in more than 40 years of isolation because of “apartheid” policies, South African companies are facing global competition. The South African automotive industry has undergone major changes over the past few years. All the assemblers are now either wholly or partially owned by overseas parent companies. Under globalisation, foreign ownership of locally owned suppliers has also been escalating. The Behr strategy and values were examined to determine whether they are consistent with companies operating in the international environment. The literature study was conducted by using textbooks, periodicals and the internet. The empirical study was conducted by means of a questionnaire addressed to the Behr executives. The results of this empirical study were then directly correlated to the theoretical aspects. Distinctive competences, market growth and product development strategies were identified and comparisons made with theory.
- Full Text:
- Date Issued: 2006
- Authors: Samuels, Donald
- Date: 2006
- Subjects: Automobile industry and trade -- South Africa , Competition, International , Globalization , Strategic planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8761 , http://hdl.handle.net/10948/600 , http://hdl.handle.net/10948/d1011685 , Automobile industry and trade -- South Africa , Competition, International , Globalization , Strategic planning
- Description: South Africa’s transition to democracy in 1994 has heralded a re-entry into the global economy. This has meant that for the first time in more than 40 years of isolation because of “apartheid” policies, South African companies are facing global competition. The South African automotive industry has undergone major changes over the past few years. All the assemblers are now either wholly or partially owned by overseas parent companies. Under globalisation, foreign ownership of locally owned suppliers has also been escalating. The Behr strategy and values were examined to determine whether they are consistent with companies operating in the international environment. The literature study was conducted by using textbooks, periodicals and the internet. The empirical study was conducted by means of a questionnaire addressed to the Behr executives. The results of this empirical study were then directly correlated to the theoretical aspects. Distinctive competences, market growth and product development strategies were identified and comparisons made with theory.
- Full Text:
- Date Issued: 2006
The establishment of normative data on Xhosa-speaking high school learners using the ImPACT 3.0 programme
- Salman-Godlo, Noluthando Cikizwa
- Authors: Salman-Godlo, Noluthando Cikizwa
- Date: 2006
- Subjects: Brain -- Concussion -- South Africa , Sports -- Psychological aspects -- South Africa , Sports injuries -- Psychological spects , Neuropsychological tests , ImPACT 3.0
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3048 , http://hdl.handle.net/10962/d1002557 , Brain -- Concussion -- South Africa , Sports -- Psychological aspects -- South Africa , Sports injuries -- Psychological spects , Neuropsychological tests , ImPACT 3.0
- Description: Concussion is a common form of brain injury, especially amongst sports players of all age groups. ImPACT is a valid and reliable measure of a variety of cognitive functions commonly affected by such injuries, which allows for objective return-to-play decision making (Iverson, Lovell, & Collins, 2003). However, studies show that the transfer of such tests from one ethnic group to another without appropriate standardization is highly problematic (Ardila, 1995). Thus, the relative absence of South African normative data for the ImPACT 3.0 programme is an issue for concern. Consequently, this study aimed to establish norms for semi-rural Xhosa-speaking schoolboys with an advantaged education (ages 14, 16 and 18) for the ImPACT 3.0 programme as administered in English. Administrative and linguistic difficulties that were experienced by individuals during completion of the battery were also identified. Finally, the study included a comparison of the percentile scores of this sample to the USA norms for boys of a similar age group. Subtests scores were generated for 70 schoolboys and the data were then subjected to statistical analysis. A significant difference between English proficiency of the Grade 8 and Grade 12 boys was found. This indicates the importance of including an English proficiency test with the ImPACT battery when assessing such populations. No other significant differences were found between these age group samples. Although this requires further investigation, the comparison of the USA and SA percentiles suggests the use of local norms for this population. South African boys in this study consistently scored lower than the USA sample. Finally, it is recommended that symptom selfreports should be verbally investigated with each boy after testing, given indications of comprehension problems. In closing, limitations and future possible studies are discussed.
- Full Text:
- Date Issued: 2006
- Authors: Salman-Godlo, Noluthando Cikizwa
- Date: 2006
- Subjects: Brain -- Concussion -- South Africa , Sports -- Psychological aspects -- South Africa , Sports injuries -- Psychological spects , Neuropsychological tests , ImPACT 3.0
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3048 , http://hdl.handle.net/10962/d1002557 , Brain -- Concussion -- South Africa , Sports -- Psychological aspects -- South Africa , Sports injuries -- Psychological spects , Neuropsychological tests , ImPACT 3.0
- Description: Concussion is a common form of brain injury, especially amongst sports players of all age groups. ImPACT is a valid and reliable measure of a variety of cognitive functions commonly affected by such injuries, which allows for objective return-to-play decision making (Iverson, Lovell, & Collins, 2003). However, studies show that the transfer of such tests from one ethnic group to another without appropriate standardization is highly problematic (Ardila, 1995). Thus, the relative absence of South African normative data for the ImPACT 3.0 programme is an issue for concern. Consequently, this study aimed to establish norms for semi-rural Xhosa-speaking schoolboys with an advantaged education (ages 14, 16 and 18) for the ImPACT 3.0 programme as administered in English. Administrative and linguistic difficulties that were experienced by individuals during completion of the battery were also identified. Finally, the study included a comparison of the percentile scores of this sample to the USA norms for boys of a similar age group. Subtests scores were generated for 70 schoolboys and the data were then subjected to statistical analysis. A significant difference between English proficiency of the Grade 8 and Grade 12 boys was found. This indicates the importance of including an English proficiency test with the ImPACT battery when assessing such populations. No other significant differences were found between these age group samples. Although this requires further investigation, the comparison of the USA and SA percentiles suggests the use of local norms for this population. South African boys in this study consistently scored lower than the USA sample. Finally, it is recommended that symptom selfreports should be verbally investigated with each boy after testing, given indications of comprehension problems. In closing, limitations and future possible studies are discussed.
- Full Text:
- Date Issued: 2006
Metathesis catalysts : an integrated computational, mechanistic and synthetic study
- Authors: Sabbagh, Ingrid Theresa
- Date: 2006
- Subjects: Metathesis (Chemistry) Catalysis Metal catalysts Chemical kinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4397 , http://hdl.handle.net/10962/d1006208
- Description: An integrated approach to the design of potential rutheniun-based metathesis catalysts is described, in which closely defined synthetic forays provide the focus and rationale for detailed computational and mechanistic studies. The ground-state geometry of a 1st-generation Grubbs catalyst has been explored at the molecular mechanics, semi-empirical and DFT levels, and the resulting structures have been shown to compare favourably with literature data and with the structure of a known crystalline analogue. The DMol³ DFT code has also been shown to represent accurately both the geometry of the corresponding co-ordinatively unsaturated monophosphine derivative, and the ligand dissociation energy associated with its formation. A DFT free-energy profile of the degenerate metathesis of ethylene has been generated, using a truncated model of the 1st-generation Grubbs catalyst, permitting location, for the first time, of the three expected transition states and providing new information regarding the rate-determining step. DFT methods have been used to facilitate the design of a tridentate camphor-derived ligand for use in the construction of a novel Grubbs-type catalyst. The phosphine ligand dissociation energy of the putative catalyst and the ethylene metathesis energy profile of a truncated model have also been studies at the DFT level. The attempted synthesis of the proposed ligand proceeded via a novel 8-bromocamphoric anhydride intermediate and afforded several unexpected and novel products, including a cisfused γ-Iactone, and a bromo camphoric acid derivative. Single crystal X-ray analysis of the latter reveals a chiral, polymeric H-bonded packing arrangement, rendering it suitable for chiral inclusion studies. Computational methods, including the GAUSSIAN-based GIAO NMR prediction technique, were used to support the structural characterisation of the novel camphor derivatives. DFT-Ievel computational analysis of the C-8- and C-9 bromination of camphor has afforded theoretical insights which permit the reconciliation of two earlier empirical explanations regarding the regioselectivity of these transformations; moreover, the theoretical results suggest that a third, previously disregarded factor, plays a significant role. A coset analysis, in conjunction with DFT-Ievel energy profiling, has also been used to resolve conflicting opinions regarding the origin of the major byproduct. Computed electronic parameters (CEP's) have been calculated for the anionic ligands involved in a series of 2nd-generation Grubbs-Hoveyda-type catalysts, and used to explain some apparently anomalous trends in catalyst activity. A linear relationship between ligand CEP's and selected ¹H NMR chemical shifts has also been demonstrated and used to identify a transient ruthenium complex in solution. The ability of the malonate di-anion to bind to ruthenium in a bidentate manner has been explored and demonstrated, under suitable conditions. DFT methods have been used to design and assess the ruthenium-chelating potential of a novel tridentate malonate derivative. A synthetic pathway to this ligand has been designed and several novel heterocyclic intermediates have been isolated and characterised. An NMR-based kinetic study of the Grubbs-catalysed self-metathesis of l-octene has been completed, and the effects of temperature, concentration and solvent variations on the kinetic parameters have been studied. Application of the Guggenheim method and a simplified mechanistic model has permitted the accurate calculation of pseudorate constants for the initiation and, for the first time, the propagation phase of the reaction. Theoretical studies of this reaction at the DFT and molecular mechanics levels have been shown to support previous assumptions regarding the selectivity and temperature-dependence of metallacycle formation.
- Full Text:
- Date Issued: 2006
- Authors: Sabbagh, Ingrid Theresa
- Date: 2006
- Subjects: Metathesis (Chemistry) Catalysis Metal catalysts Chemical kinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4397 , http://hdl.handle.net/10962/d1006208
- Description: An integrated approach to the design of potential rutheniun-based metathesis catalysts is described, in which closely defined synthetic forays provide the focus and rationale for detailed computational and mechanistic studies. The ground-state geometry of a 1st-generation Grubbs catalyst has been explored at the molecular mechanics, semi-empirical and DFT levels, and the resulting structures have been shown to compare favourably with literature data and with the structure of a known crystalline analogue. The DMol³ DFT code has also been shown to represent accurately both the geometry of the corresponding co-ordinatively unsaturated monophosphine derivative, and the ligand dissociation energy associated with its formation. A DFT free-energy profile of the degenerate metathesis of ethylene has been generated, using a truncated model of the 1st-generation Grubbs catalyst, permitting location, for the first time, of the three expected transition states and providing new information regarding the rate-determining step. DFT methods have been used to facilitate the design of a tridentate camphor-derived ligand for use in the construction of a novel Grubbs-type catalyst. The phosphine ligand dissociation energy of the putative catalyst and the ethylene metathesis energy profile of a truncated model have also been studies at the DFT level. The attempted synthesis of the proposed ligand proceeded via a novel 8-bromocamphoric anhydride intermediate and afforded several unexpected and novel products, including a cisfused γ-Iactone, and a bromo camphoric acid derivative. Single crystal X-ray analysis of the latter reveals a chiral, polymeric H-bonded packing arrangement, rendering it suitable for chiral inclusion studies. Computational methods, including the GAUSSIAN-based GIAO NMR prediction technique, were used to support the structural characterisation of the novel camphor derivatives. DFT-Ievel computational analysis of the C-8- and C-9 bromination of camphor has afforded theoretical insights which permit the reconciliation of two earlier empirical explanations regarding the regioselectivity of these transformations; moreover, the theoretical results suggest that a third, previously disregarded factor, plays a significant role. A coset analysis, in conjunction with DFT-Ievel energy profiling, has also been used to resolve conflicting opinions regarding the origin of the major byproduct. Computed electronic parameters (CEP's) have been calculated for the anionic ligands involved in a series of 2nd-generation Grubbs-Hoveyda-type catalysts, and used to explain some apparently anomalous trends in catalyst activity. A linear relationship between ligand CEP's and selected ¹H NMR chemical shifts has also been demonstrated and used to identify a transient ruthenium complex in solution. The ability of the malonate di-anion to bind to ruthenium in a bidentate manner has been explored and demonstrated, under suitable conditions. DFT methods have been used to design and assess the ruthenium-chelating potential of a novel tridentate malonate derivative. A synthetic pathway to this ligand has been designed and several novel heterocyclic intermediates have been isolated and characterised. An NMR-based kinetic study of the Grubbs-catalysed self-metathesis of l-octene has been completed, and the effects of temperature, concentration and solvent variations on the kinetic parameters have been studied. Application of the Guggenheim method and a simplified mechanistic model has permitted the accurate calculation of pseudorate constants for the initiation and, for the first time, the propagation phase of the reaction. Theoretical studies of this reaction at the DFT and molecular mechanics levels have been shown to support previous assumptions regarding the selectivity and temperature-dependence of metallacycle formation.
- Full Text:
- Date Issued: 2006
Improving the bioremediation of phenolic wastewaters by Trametes versicolor
- Ryan, D, Leukes, W, Burton, Stephanie G
- Authors: Ryan, D , Leukes, W , Burton, Stephanie G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6467 , http://hdl.handle.net/10962/d1005796 , http://dx.doi.org/10.1016/j.biortech.2006.02.001
- Description: The successful bioremediation of a phenolic wastewater by Trametes versicolor was found to be dependent on a range of factors including: fungal growth, culture age and activity and enzyme (laccase) production. These aspects were enhanced by the optimisation of the growth medium used and time of addition of the pollutant to the fungal cultures. Different media containing ‘high’ (20 g/L), ‘low’ (2 g/L) and ‘sufficient’ (10 g/L) concentrations of carbon and nitrogen sources were investigated. The medium containing both glucose and peptone at 10 g/L resulted in the highest Growth Related Productivity (the product of specific yield and μ) of laccase (1.46 Units of laccase activity)/gram biomass/day and was used in all further experiments. The use of the guaiacol as an inducer further increased laccase activity 780% without inhibiting growth; similarly the phenolic effluent studied boosted activity almost 5 times. The timing of the addition of the phenolic effluent was found to have important consequences in its removal and at least 8 days of prior growth was required. Under these conditions, 0.125 g phenol/g biomass and 0.231 g o-cresol/g biomass were removed from solution per day.
- Full Text:
- Date Issued: 2006
- Authors: Ryan, D , Leukes, W , Burton, Stephanie G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6467 , http://hdl.handle.net/10962/d1005796 , http://dx.doi.org/10.1016/j.biortech.2006.02.001
- Description: The successful bioremediation of a phenolic wastewater by Trametes versicolor was found to be dependent on a range of factors including: fungal growth, culture age and activity and enzyme (laccase) production. These aspects were enhanced by the optimisation of the growth medium used and time of addition of the pollutant to the fungal cultures. Different media containing ‘high’ (20 g/L), ‘low’ (2 g/L) and ‘sufficient’ (10 g/L) concentrations of carbon and nitrogen sources were investigated. The medium containing both glucose and peptone at 10 g/L resulted in the highest Growth Related Productivity (the product of specific yield and μ) of laccase (1.46 Units of laccase activity)/gram biomass/day and was used in all further experiments. The use of the guaiacol as an inducer further increased laccase activity 780% without inhibiting growth; similarly the phenolic effluent studied boosted activity almost 5 times. The timing of the addition of the phenolic effluent was found to have important consequences in its removal and at least 8 days of prior growth was required. Under these conditions, 0.125 g phenol/g biomass and 0.231 g o-cresol/g biomass were removed from solution per day.
- Full Text:
- Date Issued: 2006
Active learning for understanding land degradation : African Catchment Game and Riskmap
- Rowntree, Kate M, Fox, Roddy C
- Authors: Rowntree, Kate M , Fox, Roddy C
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6669 , http://hdl.handle.net/10962/d1006793
- Description: Land degradation is the result of the intersection of a complex set of biophysical and socio-economic factors. The capacity of an individual or community to address land degradation is likewise constrained. While it is quite possible for professionals and learners to grasp the main issues around land degradation from a theoretical perspective, internalizing the reality of what it means to be the resource degrader is more difficult. We have developed two active learning methods that aim to address this problem. The first is the African Catchment Game, a role-playing game based on Graham Chapman’s Green Revolution Game, adapted for the southern Africa context and incorporating a land degradation component. In this game participants play out the complex dynamics of rural-urban-global linkages against a background of environmental hazards. The second is based on Save the Children Fund’s RiskMap computer simulation that models risk in terms of rural livelihoods for different income groups. Ethiopia is used as the example. This paper evaluates the two active learning techniques as tools for exploring the relationships between land degradation and poverty through an evaluation of participants’ experiences.
- Full Text:
- Date Issued: 2006
- Authors: Rowntree, Kate M , Fox, Roddy C
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6669 , http://hdl.handle.net/10962/d1006793
- Description: Land degradation is the result of the intersection of a complex set of biophysical and socio-economic factors. The capacity of an individual or community to address land degradation is likewise constrained. While it is quite possible for professionals and learners to grasp the main issues around land degradation from a theoretical perspective, internalizing the reality of what it means to be the resource degrader is more difficult. We have developed two active learning methods that aim to address this problem. The first is the African Catchment Game, a role-playing game based on Graham Chapman’s Green Revolution Game, adapted for the southern Africa context and incorporating a land degradation component. In this game participants play out the complex dynamics of rural-urban-global linkages against a background of environmental hazards. The second is based on Save the Children Fund’s RiskMap computer simulation that models risk in terms of rural livelihoods for different income groups. Ethiopia is used as the example. This paper evaluates the two active learning techniques as tools for exploring the relationships between land degradation and poverty through an evaluation of participants’ experiences.
- Full Text:
- Date Issued: 2006
Feeding ecology, space use and habitat selection of elephants in two enclosed game reserves in the Eastern Cape Province, South Africa
- Authors: Roux, Candice
- Date: 2006
- Subjects: Shamwari Game Reserve (South Africa) , Kwandwe Game Reserve (South Africa) , Elephants -- South Africa -- Eastern Cape , Elephants -- Ecology -- South Africa -- Eastern Cape , Elephants -- Feeding -- South Africa -- Eastern Cape , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Behavior -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5699 , http://hdl.handle.net/10962/d1005385 , Shamwari Game Reserve (South Africa) , Kwandwe Game Reserve (South Africa) , Elephants -- South Africa -- Eastern Cape , Elephants -- Ecology -- South Africa -- Eastern Cape , Elephants -- Feeding -- South Africa -- Eastern Cape , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Behavior -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: The development of small (<300 km²), private game reserves has become a trend, not only in the Eastern Cape Province, but also elsewhere in South Africa as a result of a shift in land use practise from agriculture to ecotourism. The resultant re-introduction of elephants to many of these reserves has lead to management concerns because of the limited research on small reserves regarding their impact on the vegetation. In this study I assessed the space use, habitat selection, diet and impact of two elephant populations on the vegetation in the Eastern Cape Province between February 2004 and March 2005. Home range sizes were calculated using the kernel utilization distribution method. Home range sizes for elephants on Kwandwe were significantly larger during summer than winter (p<0.05). There was no significant difference between the home range sizes of the herds and males within a season and during summer the elephants utilized about 75 % of the reserve and only 54 % during winter. On Shamwari, the herd utilized about 92 % of the reserve during summer and 83 % during winter; while the males utilized 76 % of the reserve. Core areas for both elephant populations shrank from summer to winter and were concentrated around the permanent water sources on each reserve. Habitat selection was assessed using χ² tests and Bonferroni confidence intervals. On Kwandwe, there was a significant difference between observed and expected use of vegetation types (p<0.05) and karroid shrubland was strongly avoided by both herds during summer and winter. The preferred vegetation types of the males ranged from relatively open (short euphorbia thicket, bushclump karroid thicket and karroid shrubland) to completely open (old lands). On Shamwari, subtropical thicket, bontveld and montane grassland were avoided; while primary and secondary acacia thicket, riverine thicket and cultivated lands were preferred. The predominant vegetation type in the home ranges of herds on Kwandwe and Shamwari was subtropical thicket. The diet was assessed by direct observations over two seasons and dietary preferences were calculated. There was a significant difference in the frequency of occurrence of plants in the diet on the two reserves (p<0.05) and no significant effect of time of day or season (p>0.05). Seventeen woody plant species were utilized on Kwandwe and 23 species were utilized on Shamwari. Grass constituted a significantly greater percentage of the diet in summer than winter (p<0.05). Elephants on Kwandwe showed a selective preference for Ozoroa mucronata, Pappea capensis and Acacia karroo; while on Shamwari, A. karroo was selected. Transects were conducted in two different vegetation types on each reserve so as to assess the impact of elephant on the vegetation and damage scores were then calculated from these data. There was no significant effect of vegetation type or elephant density on mean damage scores in Kwandwe (p>0.05). Five hundred and seventy-eight plants were assessed in the subtropical thicket vegetation type and 225 plants were assessed in the savanna-type vegetation, with more than half the trees showing low levels of damage that could not only be attributed to elephants. Mean damage was highest for Portulacaria afra and Pappea capensis in subtropical thicket and for Rhus spp. in the savanna-type vegetation. On Shamwari, 408 plants were assessed in subtropical thicket and 215 in the savanna-type vegetation, with more than 70 % of trees showing low levels of damage. There was a significant effect of plant species and elephant density on the mean damage scores in subtropical thicket, with Aloe ferox showing more damage than the other plant species (p<0.01). In the savanna-type vegetation, A. karroo was the most severely damaged. Overall, damage was greater in the thicket vegetation type compared to the more open vegetation type on both reserves.
- Full Text:
- Date Issued: 2006
- Authors: Roux, Candice
- Date: 2006
- Subjects: Shamwari Game Reserve (South Africa) , Kwandwe Game Reserve (South Africa) , Elephants -- South Africa -- Eastern Cape , Elephants -- Ecology -- South Africa -- Eastern Cape , Elephants -- Feeding -- South Africa -- Eastern Cape , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Behavior -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5699 , http://hdl.handle.net/10962/d1005385 , Shamwari Game Reserve (South Africa) , Kwandwe Game Reserve (South Africa) , Elephants -- South Africa -- Eastern Cape , Elephants -- Ecology -- South Africa -- Eastern Cape , Elephants -- Feeding -- South Africa -- Eastern Cape , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Behavior -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: The development of small (<300 km²), private game reserves has become a trend, not only in the Eastern Cape Province, but also elsewhere in South Africa as a result of a shift in land use practise from agriculture to ecotourism. The resultant re-introduction of elephants to many of these reserves has lead to management concerns because of the limited research on small reserves regarding their impact on the vegetation. In this study I assessed the space use, habitat selection, diet and impact of two elephant populations on the vegetation in the Eastern Cape Province between February 2004 and March 2005. Home range sizes were calculated using the kernel utilization distribution method. Home range sizes for elephants on Kwandwe were significantly larger during summer than winter (p<0.05). There was no significant difference between the home range sizes of the herds and males within a season and during summer the elephants utilized about 75 % of the reserve and only 54 % during winter. On Shamwari, the herd utilized about 92 % of the reserve during summer and 83 % during winter; while the males utilized 76 % of the reserve. Core areas for both elephant populations shrank from summer to winter and were concentrated around the permanent water sources on each reserve. Habitat selection was assessed using χ² tests and Bonferroni confidence intervals. On Kwandwe, there was a significant difference between observed and expected use of vegetation types (p<0.05) and karroid shrubland was strongly avoided by both herds during summer and winter. The preferred vegetation types of the males ranged from relatively open (short euphorbia thicket, bushclump karroid thicket and karroid shrubland) to completely open (old lands). On Shamwari, subtropical thicket, bontveld and montane grassland were avoided; while primary and secondary acacia thicket, riverine thicket and cultivated lands were preferred. The predominant vegetation type in the home ranges of herds on Kwandwe and Shamwari was subtropical thicket. The diet was assessed by direct observations over two seasons and dietary preferences were calculated. There was a significant difference in the frequency of occurrence of plants in the diet on the two reserves (p<0.05) and no significant effect of time of day or season (p>0.05). Seventeen woody plant species were utilized on Kwandwe and 23 species were utilized on Shamwari. Grass constituted a significantly greater percentage of the diet in summer than winter (p<0.05). Elephants on Kwandwe showed a selective preference for Ozoroa mucronata, Pappea capensis and Acacia karroo; while on Shamwari, A. karroo was selected. Transects were conducted in two different vegetation types on each reserve so as to assess the impact of elephant on the vegetation and damage scores were then calculated from these data. There was no significant effect of vegetation type or elephant density on mean damage scores in Kwandwe (p>0.05). Five hundred and seventy-eight plants were assessed in the subtropical thicket vegetation type and 225 plants were assessed in the savanna-type vegetation, with more than half the trees showing low levels of damage that could not only be attributed to elephants. Mean damage was highest for Portulacaria afra and Pappea capensis in subtropical thicket and for Rhus spp. in the savanna-type vegetation. On Shamwari, 408 plants were assessed in subtropical thicket and 215 in the savanna-type vegetation, with more than 70 % of trees showing low levels of damage. There was a significant effect of plant species and elephant density on the mean damage scores in subtropical thicket, with Aloe ferox showing more damage than the other plant species (p<0.01). In the savanna-type vegetation, A. karroo was the most severely damaged. Overall, damage was greater in the thicket vegetation type compared to the more open vegetation type on both reserves.
- Full Text:
- Date Issued: 2006