A review of the Kalahari group: an aid to Kimberlite exploration in this medium
- Authors: Williams, Clint
- Date: 2003 , 2013-05-23
- Subjects: Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4916 , http://hdl.handle.net/10962/d1003216 , Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Description: The Kalahari Group sediments cover vast portions of the Archean Kaapvaal and Congo cratons that are considered highly prospective for economic kimberlites. In southern Africa, the term Kalahari refers to a structural basin, a group of Cretaceous to recent terrestrial continental sediments and an ill-defined desert, all of which have been grouped together as the Mega Kalahari by Thomas and Shaw (1993). The Mega Kalahari grouping includes sediments stretching from South Africa in the south to the Democratic Republic of Congo in the north, and from eastern Namibia to western Zimbabwe. This sand sea, at 2.5 million km², is the largest on earth and presents significant obstacles and challenges to the kimberlite explorationist attempting to locate bedrock-hosted diamondiferous kimberlite bodies. The Mega Kalahari sediments represent an ancient depositional environment with a complex history in which the stratigraphy and age of the deposits are not particularly well constrained or understood. Low fossil content, limited exposure, poor differentiation of the dominant surficial Kalahari Sand and a limited comprehension of an extensive duricrust suite has delayed the understanding of the sedimentological and environmental history of the basin. This sequence of sediments has accumulated and evolved through fluvio-deltaic, aeolian and groundwater processes, with characteristics due to primary deposition and subsequent modification being difficult to distinguish. Deposition in the Kalahari Basin has been subject to tectonic influences, changes in drainage directions and source areas of sediments, river capture and numerous large and small climatic fluctuations both in the basin and surrounding areas. It bears the imprint of recurring cycles during which the same sediments were reworked, sometimes by different agencies, all of which exacerbate attempts to correlate sedimentary units across the sequence. The Mega Kalahari is a series of contiguous Phanerozoic sedimentary basins situated within the African Superswell. The Superswell has dominated the gross geomorphology of southern Africa and contributed significantly to the present character of the Mega Kalahari and the evolution of the drainage systems. Overall, the tectonic framework established in southern Africa by the division of Gondwanaland led to the creation of a dual drainage system, with the hingeline acting as a watershed between a coastally-orientated exoreic system and an endoreic system draining into the interior. Deposition of sediments started in the late Cretaceous. Neo-tectonic activity expressed in the rifting in central Botswana, further influenced sedimentation rates and exerted a strong control over paleo-drainage directions. This revIew presents the complexities of the Kalahari cover sequence. The most Important geomorphological and sedimentary factors to be considered when designing and implementing kimberlite exploration programs within the Mega Kalahari environment are outlined and discussed. New data from exploration drilling programs are presented on the thickness of the Kalahari within portions of northern Namibia, western Zambia and Botswana. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Williams, Clint
- Date: 2003 , 2013-05-23
- Subjects: Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4916 , http://hdl.handle.net/10962/d1003216 , Kimberlite -- Kalahari Desert , Sedimentation and deposition -- Kalahari Desert
- Description: The Kalahari Group sediments cover vast portions of the Archean Kaapvaal and Congo cratons that are considered highly prospective for economic kimberlites. In southern Africa, the term Kalahari refers to a structural basin, a group of Cretaceous to recent terrestrial continental sediments and an ill-defined desert, all of which have been grouped together as the Mega Kalahari by Thomas and Shaw (1993). The Mega Kalahari grouping includes sediments stretching from South Africa in the south to the Democratic Republic of Congo in the north, and from eastern Namibia to western Zimbabwe. This sand sea, at 2.5 million km², is the largest on earth and presents significant obstacles and challenges to the kimberlite explorationist attempting to locate bedrock-hosted diamondiferous kimberlite bodies. The Mega Kalahari sediments represent an ancient depositional environment with a complex history in which the stratigraphy and age of the deposits are not particularly well constrained or understood. Low fossil content, limited exposure, poor differentiation of the dominant surficial Kalahari Sand and a limited comprehension of an extensive duricrust suite has delayed the understanding of the sedimentological and environmental history of the basin. This sequence of sediments has accumulated and evolved through fluvio-deltaic, aeolian and groundwater processes, with characteristics due to primary deposition and subsequent modification being difficult to distinguish. Deposition in the Kalahari Basin has been subject to tectonic influences, changes in drainage directions and source areas of sediments, river capture and numerous large and small climatic fluctuations both in the basin and surrounding areas. It bears the imprint of recurring cycles during which the same sediments were reworked, sometimes by different agencies, all of which exacerbate attempts to correlate sedimentary units across the sequence. The Mega Kalahari is a series of contiguous Phanerozoic sedimentary basins situated within the African Superswell. The Superswell has dominated the gross geomorphology of southern Africa and contributed significantly to the present character of the Mega Kalahari and the evolution of the drainage systems. Overall, the tectonic framework established in southern Africa by the division of Gondwanaland led to the creation of a dual drainage system, with the hingeline acting as a watershed between a coastally-orientated exoreic system and an endoreic system draining into the interior. Deposition of sediments started in the late Cretaceous. Neo-tectonic activity expressed in the rifting in central Botswana, further influenced sedimentation rates and exerted a strong control over paleo-drainage directions. This revIew presents the complexities of the Kalahari cover sequence. The most Important geomorphological and sedimentary factors to be considered when designing and implementing kimberlite exploration programs within the Mega Kalahari environment are outlined and discussed. New data from exploration drilling programs are presented on the thickness of the Kalahari within portions of northern Namibia, western Zambia and Botswana. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
Progress towards the development and implementation of an unambiguous copper wire fingerprinting system
- Authors: Poole, Martin
- Date: 2003
- Subjects: Electroplating , Copper , Telecommunication , Theft -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5484 , http://hdl.handle.net/10962/d1005270 , Electroplating , Copper , Telecommunication , Theft -- Prevention
- Description: The Telecommunications industry in Southern Africa is faced with the problem of theft of the signal carrying copper wire, both from the ground and from telephone poles. In many cases, if the offenders are caught, the prosecuting party has no way of proving that the wire is the property of any one Telecommunication company, as any inked markings on the insulating sheaths have been burned off along with the insulation and protective coatings themselves. Through this work we * describe the problem, * specify the necessary and preferred technical properties of a viable solution, * report the preliminary investigations into the devising of an unambiguous "fingerprinting" of the 0.5 mm wires, including some of those solutions that, upon investigation, appear non-viable, * describe the development and implementation of an electrochemical marker with detection mechanism which has shown in proof-of-principle to work, * outline the road-map of necessary future work.
- Full Text:
- Date Issued: 2003
- Authors: Poole, Martin
- Date: 2003
- Subjects: Electroplating , Copper , Telecommunication , Theft -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5484 , http://hdl.handle.net/10962/d1005270 , Electroplating , Copper , Telecommunication , Theft -- Prevention
- Description: The Telecommunications industry in Southern Africa is faced with the problem of theft of the signal carrying copper wire, both from the ground and from telephone poles. In many cases, if the offenders are caught, the prosecuting party has no way of proving that the wire is the property of any one Telecommunication company, as any inked markings on the insulating sheaths have been burned off along with the insulation and protective coatings themselves. Through this work we * describe the problem, * specify the necessary and preferred technical properties of a viable solution, * report the preliminary investigations into the devising of an unambiguous "fingerprinting" of the 0.5 mm wires, including some of those solutions that, upon investigation, appear non-viable, * describe the development and implementation of an electrochemical marker with detection mechanism which has shown in proof-of-principle to work, * outline the road-map of necessary future work.
- Full Text:
- Date Issued: 2003
A critical analysis of governance and management in Zimbabwe's colleges of technical and vocational education: issues for revitalisation
- Authors: Mbizvo, Washington T
- Date: 2003
- Subjects: Education, Higher -- Zimbabwe Universities and colleges -- Zimbabwe Universities and colleges -- Zimbabwe -- Administration Vocational education -- Zimbabwe Technical education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1469 , http://hdl.handle.net/10962/d1003350
- Description: This research was carried out in order to gain a better understanding of the practice of governance in a technical or vocationally oriented college and the critical role played by the principal as a college manager within the governance system in which industrialists and head office are also key players. Conceptual literature relating to issues of governance and management within the education scenario is examined. The wider issues of governance are critically analysed in the context of power and control mechanisms initiated by the Ministry of Higher Education as the responsible authority for the colleges. The influence of the industrial sector as the consumers of skilled labour force is analysed through college advisory councils set up in terms of the relevant pieces of legislation. The research is qualitative and takes the form of three case studies of technical and vocational colleges in Zimbabwe. Data were collected through multiple methods from varied sources with a view to ensuring triangulation. The multiple-case design enabled me to dig beneath the surface of what apparently happens in these organisations and unearth issues and concerns at the wider governance and management levels. Views and experiences of participants are captured and explained through in-depth interviews, observations and documentary sources. Results are discussed in relation to the relevant literature allowing grounded theory to emerge. The research highlights the roles of key players in governance and the issues of relationships among these actors. What emerges is a desperate situation of ineffectiveness, problematic processes in governance and poor responsiveness of these colleges to the labour market demands. The potential for generalisability and transferability is discussed in the report and possible corrective intervention strategies are recommended. The thesis demonstrates that managers of these colleges and indeed senior officers in head office who are at the centre of governance and will need transformational leadership development in order for them to come to terms with such things as people’s feelings, abandoning ‘outdated’ policies, managing change, and handling communication effectively. Various strategies for revitalisation of governance and management in technical and vocational colleges are suggested.
- Full Text:
- Date Issued: 2003
- Authors: Mbizvo, Washington T
- Date: 2003
- Subjects: Education, Higher -- Zimbabwe Universities and colleges -- Zimbabwe Universities and colleges -- Zimbabwe -- Administration Vocational education -- Zimbabwe Technical education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1469 , http://hdl.handle.net/10962/d1003350
- Description: This research was carried out in order to gain a better understanding of the practice of governance in a technical or vocationally oriented college and the critical role played by the principal as a college manager within the governance system in which industrialists and head office are also key players. Conceptual literature relating to issues of governance and management within the education scenario is examined. The wider issues of governance are critically analysed in the context of power and control mechanisms initiated by the Ministry of Higher Education as the responsible authority for the colleges. The influence of the industrial sector as the consumers of skilled labour force is analysed through college advisory councils set up in terms of the relevant pieces of legislation. The research is qualitative and takes the form of three case studies of technical and vocational colleges in Zimbabwe. Data were collected through multiple methods from varied sources with a view to ensuring triangulation. The multiple-case design enabled me to dig beneath the surface of what apparently happens in these organisations and unearth issues and concerns at the wider governance and management levels. Views and experiences of participants are captured and explained through in-depth interviews, observations and documentary sources. Results are discussed in relation to the relevant literature allowing grounded theory to emerge. The research highlights the roles of key players in governance and the issues of relationships among these actors. What emerges is a desperate situation of ineffectiveness, problematic processes in governance and poor responsiveness of these colleges to the labour market demands. The potential for generalisability and transferability is discussed in the report and possible corrective intervention strategies are recommended. The thesis demonstrates that managers of these colleges and indeed senior officers in head office who are at the centre of governance and will need transformational leadership development in order for them to come to terms with such things as people’s feelings, abandoning ‘outdated’ policies, managing change, and handling communication effectively. Various strategies for revitalisation of governance and management in technical and vocational colleges are suggested.
- Full Text:
- Date Issued: 2003
Locating the institution of traditional leadership within the institutional framework of South Africa's new democracy
- Authors: Mashele, Hlukanisa Prince
- Date: 2003
- Subjects: Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2858 , http://hdl.handle.net/10962/d1007512 , Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
- Description: This study looks into the role of the institution of traditional leadership in post-apartheid South Africa. It seeks to critically engage the debate on how to locate the institution within the new politico-constitutional framework. This is done with the main objective of proposing an altemative to the current state of affairs vis-à-vis traditional leadership and governance in South Africa. In order to clear the ground, the study first deals with the important question of democracy in relation to the institution of traditional leadership. In this regard, the study unearthed that the institution of traditional leadership is fundamentally undemocratic in character, as it is largely based on heredity and devoid of principles of democracy such as equality, accountability, etc. In order to put matters into perspective the study also delves into the history of the institution of traditional leadership with the aim of getting to the role that traditional leaders played in various epochs of South Africa's political development. This investigation reveals that the denting of the integrity of the institution of traditional leadership began with the advent of colonialism and worsened by successive apartheid regimes. It is at these stages of development that the institution was subordinated to a higher authority that sought to use the institution as an instrument of domination and oppression of the black majority. Considering this role, it would seem that the place that the space that the institution occupies in the post-apartheid South African governance framework is a compromise. The institution plays an advisory role at all levels of government - with their houses in both national and provincial legislatures, whilst traditional leaders sit as ex-officio members on local councils. However, traditional leaders fiercely contest this position as, in their view, this limits their powers. The main argument of this study is that for traditional leaders to be given an advisory role in the current and future governance framework of the country is a step in the right direction, as that serves to insulate the institution from active politics. For that reason, the study recommends that the institution of traditional leadership should occupy a cultural space in society - meaning that it should be responsible for the preservation of African customs and culture. This, therefore, means that the institution is better-placed to advise government on cultural and customary aspects of development. Whilst playing this role, the institution of traditional leadership should also -be brought into line with democratic ways of governance.
- Full Text:
- Date Issued: 2003
- Authors: Mashele, Hlukanisa Prince
- Date: 2003
- Subjects: Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2858 , http://hdl.handle.net/10962/d1007512 , Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
- Description: This study looks into the role of the institution of traditional leadership in post-apartheid South Africa. It seeks to critically engage the debate on how to locate the institution within the new politico-constitutional framework. This is done with the main objective of proposing an altemative to the current state of affairs vis-à-vis traditional leadership and governance in South Africa. In order to clear the ground, the study first deals with the important question of democracy in relation to the institution of traditional leadership. In this regard, the study unearthed that the institution of traditional leadership is fundamentally undemocratic in character, as it is largely based on heredity and devoid of principles of democracy such as equality, accountability, etc. In order to put matters into perspective the study also delves into the history of the institution of traditional leadership with the aim of getting to the role that traditional leaders played in various epochs of South Africa's political development. This investigation reveals that the denting of the integrity of the institution of traditional leadership began with the advent of colonialism and worsened by successive apartheid regimes. It is at these stages of development that the institution was subordinated to a higher authority that sought to use the institution as an instrument of domination and oppression of the black majority. Considering this role, it would seem that the place that the space that the institution occupies in the post-apartheid South African governance framework is a compromise. The institution plays an advisory role at all levels of government - with their houses in both national and provincial legislatures, whilst traditional leaders sit as ex-officio members on local councils. However, traditional leaders fiercely contest this position as, in their view, this limits their powers. The main argument of this study is that for traditional leaders to be given an advisory role in the current and future governance framework of the country is a step in the right direction, as that serves to insulate the institution from active politics. For that reason, the study recommends that the institution of traditional leadership should occupy a cultural space in society - meaning that it should be responsible for the preservation of African customs and culture. This, therefore, means that the institution is better-placed to advise government on cultural and customary aspects of development. Whilst playing this role, the institution of traditional leadership should also -be brought into line with democratic ways of governance.
- Full Text:
- Date Issued: 2003
Synthesis of zinc phthalocyanine derivatives for possible use in photodynamic therapy
- Authors: Matlaba, Pulane Maseleka
- Date: 2003
- Subjects: Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4374 , http://hdl.handle.net/10962/d1005039 , Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Description: The synthesis of symmetrically and unsymmetrically substituted zinc phthalocyanines (ZnPc) derivatives is done according to reported procedures. The unsymmetrical ZnPc derivatives are synthesized by ring expansion of sub-phthalocyanine complexes. Ring substitution is effected with tert-butyl phenol, naphthol, and hydroxybenzoic acid. Comparison of the redox potentials for the complexes substituted with varying numbers of tert-butyl phenol: 1, 2, 3, 6 and 8 show that the complex with the highest number of substituents are more difficult to oxidize and easier to reduce. Water soluble sulphonated ZnPc (ZnPcSn) was prepared. The possibility of using axial ligation to increase the solubility and the photochemical activity of sulphotnated ZnPc in aqueous solutions was investigated. Pyridine, aminopyridyl and bipyridyl were used as axial ligands. When bipyridyl was used as the axial ligand, solubility of the ZnPcSn increased, shown by the increase in the Q-band of the monomer species in solution and the singlet oxygen quantum yields was relatively higher than that of the unligated ZnPcSn. The singlet oxygen quantum yields by the various complexes in DMF using diphenylisobenzofuran as a chemical quencher for organic solvent were determined. Singlet oxygen quantum yields for the unsymmetrically ring substituted complexes range from 0.22 to 0.68. Photobleaching quantum yields are in the order of 10-5, which means that the complexes are relatively photostable.
- Full Text:
- Date Issued: 2003
- Authors: Matlaba, Pulane Maseleka
- Date: 2003
- Subjects: Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4374 , http://hdl.handle.net/10962/d1005039 , Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Description: The synthesis of symmetrically and unsymmetrically substituted zinc phthalocyanines (ZnPc) derivatives is done according to reported procedures. The unsymmetrical ZnPc derivatives are synthesized by ring expansion of sub-phthalocyanine complexes. Ring substitution is effected with tert-butyl phenol, naphthol, and hydroxybenzoic acid. Comparison of the redox potentials for the complexes substituted with varying numbers of tert-butyl phenol: 1, 2, 3, 6 and 8 show that the complex with the highest number of substituents are more difficult to oxidize and easier to reduce. Water soluble sulphonated ZnPc (ZnPcSn) was prepared. The possibility of using axial ligation to increase the solubility and the photochemical activity of sulphotnated ZnPc in aqueous solutions was investigated. Pyridine, aminopyridyl and bipyridyl were used as axial ligands. When bipyridyl was used as the axial ligand, solubility of the ZnPcSn increased, shown by the increase in the Q-band of the monomer species in solution and the singlet oxygen quantum yields was relatively higher than that of the unligated ZnPcSn. The singlet oxygen quantum yields by the various complexes in DMF using diphenylisobenzofuran as a chemical quencher for organic solvent were determined. Singlet oxygen quantum yields for the unsymmetrically ring substituted complexes range from 0.22 to 0.68. Photobleaching quantum yields are in the order of 10-5, which means that the complexes are relatively photostable.
- Full Text:
- Date Issued: 2003
Structural and synthetic investigations of diterpenoid natural products from southern African marine invertebrates
- Authors: Gray, Christopher Anthony
- Date: 2003
- Subjects: Ethyl acetoacetate Diterpenes Limpets -- South Africa Natural products -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4349 , http://hdl.handle.net/10962/d1005014
- Description: This thesis is divided into two parts. The first part (Chapter Two) documents a bioassay guided investigation of the ethyl acetate extracts of four marine invertebrates from Mozambique (an Irciniid sponge, a Haliclona sp. sponge, an ascidian tentatively identified as Diplosoma sp., and the soft coral Cladiella kashmani). Eight known compounds [ilimaquinone (2.1), renierone (2.7), N-formyl-1,2-dihydrorenierone (2.8), 1,6-dimethyl-7-methoxy-5,8-dihydroisoquinoline-5,8-dione (2.9), mimosamycin (2.10) 7Z-allylidene-5-hydroxy-7,7a-dihydro-2H-cyclopenta[b]pyran-6-one (2.11), flaccidoxide (2.18) and 11S,12S-epoxycembra-1Z,3E,7E-trien-14S-ol (2.19)] and a new diterpene [13S,14R-diacetoxy-11S,12R-epoxycembra-1Z,3E,7E-triene (2.20)] were isolated and identified using standard spectroscopic techniques. Anomalies in the published spectral data of 2.1 and 2.8 were exposed and corrected, and the absolute stereochemistry of the cembrane diterpenes 2.18 and 2.20 established using the modified Mosher’s method. The comparative activities of the nine natural products against four cancer cell lines (A549, LOX, OVCAR3, SNB19) are reported. The second part of the thesis (Chapter Three – Chapter Six) is concerned with an ecological, structural and synthetic study of diterpenes from the endemic South African pulmonate limpet Trimusculus costatus. Two new labdane diterpenes [6b,7a-diacetoxylabda-8,13E-dien-15-ol (3.10) and 2a,6b,7a-triacetoxylabda-8,13E-dien-15-ol (3.11)] were isolated from T. costatus and evaluated for anti-feeding activity against the common predatory fish Pomadasys commersonnii. A strategy for the semi-synthesis of 3.10 from rhinocerotinoic acid (4.14), a diterpene reportedly present in the ubiquitous South African shrub Elytropappus rhinocerotis, was devised in order to allow further bioactivity tests to be performed and unequivocally assign the unknown absolute stereochemistry of the T. costatus metabolites. Attempts to isolate rhinocerotinoic acid from local specimens of Elytropappus rhinocerotis were unsuccessful, and as the repetition of a published synthesis of 4.14 from (-)-sclareol (4.15) gave rhinocerotinoic acid in unacceptably low yields with poor stereoselectivity, an improved synthesis of 4.14 is presented. Comprehensive studies using hispanone (5.1) as a model compound showed that 6,7-dioxygenated labda-8-enes could be prepared from compounds possessing a 7-oxo-labda-8-ene skeleton with some degree of stereocontrol. In the process, fourteen new hispanone analogues were prepared and most of these were tested for activity in a suite of ten agro-chemical assays. The novel compound 7b-hydroxy-9a-carbonitrile-15,16-epoxylabda-13(16),14-dien-6-one (5.34) exhibited significant activity against the crop fungus Phytophthora infestans and is currently being subjected to further agro-chemical tests. Unfortunately, the results from the oxygenation study performed on the model compound 5.1 could not be directly extrapolated to rhinocerotinoic acid. Attempts to prepare the naturally occurring 3.10 from 4.14 via an alternative route were unsuccessful but yielded an analogue of 3.10 in which the substituents at C-6 and C-7 are in a diequatorial rather than a diaxial configuration.
- Full Text:
- Date Issued: 2003
- Authors: Gray, Christopher Anthony
- Date: 2003
- Subjects: Ethyl acetoacetate Diterpenes Limpets -- South Africa Natural products -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4349 , http://hdl.handle.net/10962/d1005014
- Description: This thesis is divided into two parts. The first part (Chapter Two) documents a bioassay guided investigation of the ethyl acetate extracts of four marine invertebrates from Mozambique (an Irciniid sponge, a Haliclona sp. sponge, an ascidian tentatively identified as Diplosoma sp., and the soft coral Cladiella kashmani). Eight known compounds [ilimaquinone (2.1), renierone (2.7), N-formyl-1,2-dihydrorenierone (2.8), 1,6-dimethyl-7-methoxy-5,8-dihydroisoquinoline-5,8-dione (2.9), mimosamycin (2.10) 7Z-allylidene-5-hydroxy-7,7a-dihydro-2H-cyclopenta[b]pyran-6-one (2.11), flaccidoxide (2.18) and 11S,12S-epoxycembra-1Z,3E,7E-trien-14S-ol (2.19)] and a new diterpene [13S,14R-diacetoxy-11S,12R-epoxycembra-1Z,3E,7E-triene (2.20)] were isolated and identified using standard spectroscopic techniques. Anomalies in the published spectral data of 2.1 and 2.8 were exposed and corrected, and the absolute stereochemistry of the cembrane diterpenes 2.18 and 2.20 established using the modified Mosher’s method. The comparative activities of the nine natural products against four cancer cell lines (A549, LOX, OVCAR3, SNB19) are reported. The second part of the thesis (Chapter Three – Chapter Six) is concerned with an ecological, structural and synthetic study of diterpenes from the endemic South African pulmonate limpet Trimusculus costatus. Two new labdane diterpenes [6b,7a-diacetoxylabda-8,13E-dien-15-ol (3.10) and 2a,6b,7a-triacetoxylabda-8,13E-dien-15-ol (3.11)] were isolated from T. costatus and evaluated for anti-feeding activity against the common predatory fish Pomadasys commersonnii. A strategy for the semi-synthesis of 3.10 from rhinocerotinoic acid (4.14), a diterpene reportedly present in the ubiquitous South African shrub Elytropappus rhinocerotis, was devised in order to allow further bioactivity tests to be performed and unequivocally assign the unknown absolute stereochemistry of the T. costatus metabolites. Attempts to isolate rhinocerotinoic acid from local specimens of Elytropappus rhinocerotis were unsuccessful, and as the repetition of a published synthesis of 4.14 from (-)-sclareol (4.15) gave rhinocerotinoic acid in unacceptably low yields with poor stereoselectivity, an improved synthesis of 4.14 is presented. Comprehensive studies using hispanone (5.1) as a model compound showed that 6,7-dioxygenated labda-8-enes could be prepared from compounds possessing a 7-oxo-labda-8-ene skeleton with some degree of stereocontrol. In the process, fourteen new hispanone analogues were prepared and most of these were tested for activity in a suite of ten agro-chemical assays. The novel compound 7b-hydroxy-9a-carbonitrile-15,16-epoxylabda-13(16),14-dien-6-one (5.34) exhibited significant activity against the crop fungus Phytophthora infestans and is currently being subjected to further agro-chemical tests. Unfortunately, the results from the oxygenation study performed on the model compound 5.1 could not be directly extrapolated to rhinocerotinoic acid. Attempts to prepare the naturally occurring 3.10 from 4.14 via an alternative route were unsuccessful but yielded an analogue of 3.10 in which the substituents at C-6 and C-7 are in a diequatorial rather than a diaxial configuration.
- Full Text:
- Date Issued: 2003
Effects of small-scale water movement on the settlement and growth rates of the brown mussel Perna perna, on the south-east coast of South Africa
- Authors: Mathagu, Tendamudzimu Titus
- Date: 2003
- Subjects: Mussels -- South Africa , Perna -- South Africa , Perna -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5682 , http://hdl.handle.net/10962/d1005368 , Mussels -- South Africa , Perna -- South Africa , Perna -- Growth
- Description: The effects of small scale (cm) water movement on the settlement and growth rates of the brown mussel Perna perna were investigated on the south-east coast of South Africa (33°28′S, 27°10′E). L-shaped metal baffles attached to the substratum decreased the erosion rates of cement balls and it was concluded that the baffles decreased the water flow rate around cement balls. These L-shaped baffles were then used to decrease water flow rates around mussel patches and pot-scouring pads used as artificial substrata for the settlement of P.perna larvae. Anova indicated that settlement rate varied by date and site while decreased water flow rate significantly increased larval settlement (p<0.05), only on the site and day that had the overall highest number of settlers. Mussels in the low zone had significantly higher growth rates than those in the high zone. Decreased water flow rate significantly increased mussel growth rate in the lower zone (Anova, p<0.05), while it did not have a significant effect on the mussel in the high zone. Thus water flow manipulation increased growth rates in the zone, which already had high growth rate. It was concluded that small-scale (cm) water flow patterns have an effect on both Perna perna settlement and growth rates, but only under specific conditions. Larval settlement rate was significantly increased by water flow manipulation on the site and day that had the highest number of settlers. Growth rates were significantly increased by decreased water flow rate only in the low zone, where growth rates are the highest. Although water flow was manipulated in both zones its effect in the high zone was insignificant (Anova) compared to other factors affecting growth rates at this tidal level.
- Full Text:
- Date Issued: 2003
- Authors: Mathagu, Tendamudzimu Titus
- Date: 2003
- Subjects: Mussels -- South Africa , Perna -- South Africa , Perna -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5682 , http://hdl.handle.net/10962/d1005368 , Mussels -- South Africa , Perna -- South Africa , Perna -- Growth
- Description: The effects of small scale (cm) water movement on the settlement and growth rates of the brown mussel Perna perna were investigated on the south-east coast of South Africa (33°28′S, 27°10′E). L-shaped metal baffles attached to the substratum decreased the erosion rates of cement balls and it was concluded that the baffles decreased the water flow rate around cement balls. These L-shaped baffles were then used to decrease water flow rates around mussel patches and pot-scouring pads used as artificial substrata for the settlement of P.perna larvae. Anova indicated that settlement rate varied by date and site while decreased water flow rate significantly increased larval settlement (p<0.05), only on the site and day that had the overall highest number of settlers. Mussels in the low zone had significantly higher growth rates than those in the high zone. Decreased water flow rate significantly increased mussel growth rate in the lower zone (Anova, p<0.05), while it did not have a significant effect on the mussel in the high zone. Thus water flow manipulation increased growth rates in the zone, which already had high growth rate. It was concluded that small-scale (cm) water flow patterns have an effect on both Perna perna settlement and growth rates, but only under specific conditions. Larval settlement rate was significantly increased by water flow manipulation on the site and day that had the highest number of settlers. Growth rates were significantly increased by decreased water flow rate only in the low zone, where growth rates are the highest. Although water flow was manipulated in both zones its effect in the high zone was insignificant (Anova) compared to other factors affecting growth rates at this tidal level.
- Full Text:
- Date Issued: 2003
Genetic variation within two pulmonate limpet species, Siphonaria capensis and S. serrata along the South African coast
- Authors: Seaman, Jennifer Ann
- Date: 2003
- Subjects: Limpets -- South Africa Pulmonata Siphonaria Limpets -- Genetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5800 , http://hdl.handle.net/10962/d1006155
- Description: Dispersal rates are known to play a fundamental role in establishing the genetic structure found within a species. Dispersal in marine benthic invertebrates is largely dependent on life history strategy. The presence of pelagic larvae will potentially result in high dispersal within a species, while direct development limits dispersal. This study used two intertidal pulmonate limpet species to investigate the relationship between dispersal potential and genetic structure of populations. Siphonaria capensis produces benthic egg masses, which release pelagic larvae. These float in ocean currents before settling and metamorphosing into adults. S. serrata reproduces by direct development. The larvae hatch as completely metamorphosed juveniles after developing in an egg case not far from the parent. The high dispersal capacity of S. capensis pelagic larvae should result in high levels of within-population variation since individuals within a particular population may originate from several different populations. This should lead to high levels of gene flow along the coast and to low genetic differentiation among populations. On the other hand, the low dispersal potential of S. serrata should cause low levels of genetic variation within populations, as relatives will remain close to one another. Low levels of gene flow and high genetic differentiation among populations are expected in this species. In dealing with the relationship between life history strategy and population genetic structure in these two species, a series of indirect techniques was utilised. Multivariate analyses of the morphological variation within each species showed that variation in size was similar between the two species and largely governed by environmental factors. Variation in shell shape was largely under genetic control and supported the predictions made for each species. Variation in total proteins was relatively uninformative in terms of examining the differences between the two species. Allozyme analysis and mtDNA sequencing clearly showed differences between the species in terms of their population genetic structure. High levels of gene flow were found within S. capensis. This was strongly influenced by ocean currents, with the close inshore Agulhas current along the Transkei coast contributing to high levels of dispersal and hence gene flow. Low levels of gene flow occurred within S. serrata, resulting in low within-population variation and high among-population differentiation.
- Full Text:
- Date Issued: 2003
- Authors: Seaman, Jennifer Ann
- Date: 2003
- Subjects: Limpets -- South Africa Pulmonata Siphonaria Limpets -- Genetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5800 , http://hdl.handle.net/10962/d1006155
- Description: Dispersal rates are known to play a fundamental role in establishing the genetic structure found within a species. Dispersal in marine benthic invertebrates is largely dependent on life history strategy. The presence of pelagic larvae will potentially result in high dispersal within a species, while direct development limits dispersal. This study used two intertidal pulmonate limpet species to investigate the relationship between dispersal potential and genetic structure of populations. Siphonaria capensis produces benthic egg masses, which release pelagic larvae. These float in ocean currents before settling and metamorphosing into adults. S. serrata reproduces by direct development. The larvae hatch as completely metamorphosed juveniles after developing in an egg case not far from the parent. The high dispersal capacity of S. capensis pelagic larvae should result in high levels of within-population variation since individuals within a particular population may originate from several different populations. This should lead to high levels of gene flow along the coast and to low genetic differentiation among populations. On the other hand, the low dispersal potential of S. serrata should cause low levels of genetic variation within populations, as relatives will remain close to one another. Low levels of gene flow and high genetic differentiation among populations are expected in this species. In dealing with the relationship between life history strategy and population genetic structure in these two species, a series of indirect techniques was utilised. Multivariate analyses of the morphological variation within each species showed that variation in size was similar between the two species and largely governed by environmental factors. Variation in shell shape was largely under genetic control and supported the predictions made for each species. Variation in total proteins was relatively uninformative in terms of examining the differences between the two species. Allozyme analysis and mtDNA sequencing clearly showed differences between the species in terms of their population genetic structure. High levels of gene flow were found within S. capensis. This was strongly influenced by ocean currents, with the close inshore Agulhas current along the Transkei coast contributing to high levels of dispersal and hence gene flow. Low levels of gene flow occurred within S. serrata, resulting in low within-population variation and high among-population differentiation.
- Full Text:
- Date Issued: 2003
The social construction of "sexual knowledge": exploring the narratives of southern African youth of Indian descent in the context of HIV/AIDS
- Authors: Esat, Fazila
- Date: 2003
- Subjects: East Indians -- South Africa -- Attitudes , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Sexual behavior , Youth -- South Africa -- Sexual behavior , AIDS (Disease) -- Social aspects -- South Africa , HIV infections -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2970 , http://hdl.handle.net/10962/d1002479 , East Indians -- South Africa -- Attitudes , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Sexual behavior , Youth -- South Africa -- Sexual behavior , AIDS (Disease) -- Social aspects -- South Africa , HIV infections -- Social aspects -- South Africa
- Description: This study pays attention to youth of Indian-descent within the context of sexuality and identity and their role in HIV/AIDS. By gaining an understanding of this interaction between identity and sexuality, it adds to our knowledge of the social dynamics that contribute to the prevalence or lack of prevalence of HIV/AIDS within population groups. This study uses a social constructionist discourse analytic framework and aims to explore the construction of sexual knowledge by Southern African youth of Indian-descent. The findings indicate that the construction of sex is primarily one of risk and ambiguity. Additionally, the construction of sexual knowledge highlights the significance of gender differentials and the importance of agency and responsibility for sexual education. These constructions reinforce traditional educational roles that contribute to the construction of sex as risky and ambiguous. In addition, a social identity of Indian-ness and othering is used as a strategy to give meaning to the lack of parental responsibility with regard to sexual education. The use of social identity is seen as highlighting the importance of acknowledging the sexual values within which youth are embedded. This study concludes with possible ways to shift these constructions. For example, one of the conclusions suggests the implementation of an alternative school-based sexual education that acknowledges the sexual values in which youth are embedded. Furthermore, this acknowledgement of sexual values should take place within a holistic sex education programme that is positive about sexuality. Additionally, a reframing of youth as capable and active decision-makers in their sexual education is necessitated in order to see youth as a potential resource in HIV/AIDS prevention.
- Full Text:
- Date Issued: 2003
- Authors: Esat, Fazila
- Date: 2003
- Subjects: East Indians -- South Africa -- Attitudes , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Sexual behavior , Youth -- South Africa -- Sexual behavior , AIDS (Disease) -- Social aspects -- South Africa , HIV infections -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2970 , http://hdl.handle.net/10962/d1002479 , East Indians -- South Africa -- Attitudes , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Sexual behavior , Youth -- South Africa -- Sexual behavior , AIDS (Disease) -- Social aspects -- South Africa , HIV infections -- Social aspects -- South Africa
- Description: This study pays attention to youth of Indian-descent within the context of sexuality and identity and their role in HIV/AIDS. By gaining an understanding of this interaction between identity and sexuality, it adds to our knowledge of the social dynamics that contribute to the prevalence or lack of prevalence of HIV/AIDS within population groups. This study uses a social constructionist discourse analytic framework and aims to explore the construction of sexual knowledge by Southern African youth of Indian-descent. The findings indicate that the construction of sex is primarily one of risk and ambiguity. Additionally, the construction of sexual knowledge highlights the significance of gender differentials and the importance of agency and responsibility for sexual education. These constructions reinforce traditional educational roles that contribute to the construction of sex as risky and ambiguous. In addition, a social identity of Indian-ness and othering is used as a strategy to give meaning to the lack of parental responsibility with regard to sexual education. The use of social identity is seen as highlighting the importance of acknowledging the sexual values within which youth are embedded. This study concludes with possible ways to shift these constructions. For example, one of the conclusions suggests the implementation of an alternative school-based sexual education that acknowledges the sexual values in which youth are embedded. Furthermore, this acknowledgement of sexual values should take place within a holistic sex education programme that is positive about sexuality. Additionally, a reframing of youth as capable and active decision-makers in their sexual education is necessitated in order to see youth as a potential resource in HIV/AIDS prevention.
- Full Text:
- Date Issued: 2003
The development and evaluation of Cryptophlebia Leucotreta granulovirus (CrleGV) as a biological control agent for the management of false codling moth, Cryptophlebia Leucotreta, on citrus
- Authors: Moore, Sean Douglas
- Date: 2003
- Subjects: Cryptophlebia leucotreta Cryptophlebia leucotreta -- Control Pests -- Biological control Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3942 , http://hdl.handle.net/10962/d1004001
- Description: A granulovirus isolated from Cryptophlebia leucotreta larvae was shown through restriction endonuclease analysis to be a novel strain (CrleGV-SA). No more than one isolate could be identified from a laboratory culture of C. leucotreta. However, a preliminary examination of restricted DNA profiles of isolates from different geographical regions indicated some minor differences. In surface dose bioassays on artificial diet, LC50 and LC90 values with neonate larvae were estimated to be 4.095 x 103 OBs/ml and 1.185 x 105 OBs/ml respectively. LT50 and LT90 values with neonate larvae were estimated to be 4 days 22 h and 7 days 8 h, respectively. Detached fruit (navel orange) bioassays with neonate larvae indicated that virus concentrations that are likely to be effective in the field range from 1.08 x 107 to 3.819 x 1010 OBs/ml. In surface dose bioassays with fifth instar larvae LC50 and LC90 values were estimated to be 2.678 x 107 OBs/ml and 9.118 x 109 OBs/ml respectively. LT50 and LT90 values were estimated to be 7 days 17 h and 9 days 8 h, respectively. A new artificial diet for mass rearing the host was developed. Microbial contamination of diet was significantly reduced by adding nipagin and sorbic acid to the diet and by surface sterilising C. leucotreta eggs with Sporekill. Almost 20 % more eggs were produced from moths reared on the new diet compared to moths reared on the old diet. A further 9 % improvement in egg production and a reduction in the labour required to produce eggs, was made with the development of a new oviposition cage attached to the moth eclosion box. Virus was mass produced in fifth instar C. leucotreta larvae by surface inoculating diet with the LC90. When 300 individuals were placed onto inoculated diet, 56 % of them were recovered six to 11 days later as infected larvae. Mean larval equivalents was 1.158 x 1011 OBs/larva. When larvae and diet were harvested together, highest yields of virus were achieved at eight days after inoculation. Microbial contamination in semi-purified preparations of CrleGV ranged from 176211 to 433594 (OB:CFU ratio). Half-life of CrleGV in the field was estimated to be less than 1 day on the northern aspect of trees and between 3 - 6 days on the southern aspect. Original activity remaining (OAR) of the virus dropped below 50 % after 5 days on the northern aspect of trees and was still at 69 % on the southern aspect of trees after 3 weeks. In field trials, CrleGV reduced C. leucotreta infestation of navel oranges by up to 60 % for a period of 39 days. CrleGV in combination with augmentation of the C. leucotreta egg parasitoid, Trichogrammatoidea cryptophlebiae, reduced infestation by 70 %. The integration of CrleGV into an integrated pest management (IPM) system for the management of C. leucotreta on citrus is proposed.
- Full Text:
- Date Issued: 2003
- Authors: Moore, Sean Douglas
- Date: 2003
- Subjects: Cryptophlebia leucotreta Cryptophlebia leucotreta -- Control Pests -- Biological control Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3942 , http://hdl.handle.net/10962/d1004001
- Description: A granulovirus isolated from Cryptophlebia leucotreta larvae was shown through restriction endonuclease analysis to be a novel strain (CrleGV-SA). No more than one isolate could be identified from a laboratory culture of C. leucotreta. However, a preliminary examination of restricted DNA profiles of isolates from different geographical regions indicated some minor differences. In surface dose bioassays on artificial diet, LC50 and LC90 values with neonate larvae were estimated to be 4.095 x 103 OBs/ml and 1.185 x 105 OBs/ml respectively. LT50 and LT90 values with neonate larvae were estimated to be 4 days 22 h and 7 days 8 h, respectively. Detached fruit (navel orange) bioassays with neonate larvae indicated that virus concentrations that are likely to be effective in the field range from 1.08 x 107 to 3.819 x 1010 OBs/ml. In surface dose bioassays with fifth instar larvae LC50 and LC90 values were estimated to be 2.678 x 107 OBs/ml and 9.118 x 109 OBs/ml respectively. LT50 and LT90 values were estimated to be 7 days 17 h and 9 days 8 h, respectively. A new artificial diet for mass rearing the host was developed. Microbial contamination of diet was significantly reduced by adding nipagin and sorbic acid to the diet and by surface sterilising C. leucotreta eggs with Sporekill. Almost 20 % more eggs were produced from moths reared on the new diet compared to moths reared on the old diet. A further 9 % improvement in egg production and a reduction in the labour required to produce eggs, was made with the development of a new oviposition cage attached to the moth eclosion box. Virus was mass produced in fifth instar C. leucotreta larvae by surface inoculating diet with the LC90. When 300 individuals were placed onto inoculated diet, 56 % of them were recovered six to 11 days later as infected larvae. Mean larval equivalents was 1.158 x 1011 OBs/larva. When larvae and diet were harvested together, highest yields of virus were achieved at eight days after inoculation. Microbial contamination in semi-purified preparations of CrleGV ranged from 176211 to 433594 (OB:CFU ratio). Half-life of CrleGV in the field was estimated to be less than 1 day on the northern aspect of trees and between 3 - 6 days on the southern aspect. Original activity remaining (OAR) of the virus dropped below 50 % after 5 days on the northern aspect of trees and was still at 69 % on the southern aspect of trees after 3 weeks. In field trials, CrleGV reduced C. leucotreta infestation of navel oranges by up to 60 % for a period of 39 days. CrleGV in combination with augmentation of the C. leucotreta egg parasitoid, Trichogrammatoidea cryptophlebiae, reduced infestation by 70 %. The integration of CrleGV into an integrated pest management (IPM) system for the management of C. leucotreta on citrus is proposed.
- Full Text:
- Date Issued: 2003
Religious nationalism and negotiation : Islamic identity and the resolution of the Israel/Palestine conflic
- Authors: De Villiers, Shirley
- Date: 2004
- Subjects: Arab-Israeli conflict Palestinian Arabs -- Civil rights -- Israel Nationalism -- Middle East Religion and politics -- Middle East Jewish-Arab relations Nationalism -- Religious aspects -- Islam -- History -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2873 , http://hdl.handle.net/10962/d1007815
- Description: The use of violence in the Israel/Palestine conflict has been justified and legitimised by an appeal to religion. Militant Islamist organisations like Ramas have become central players in the Palestinian political landscape as a result of the popular support that they enjoy. This thesis aims to investigate the reasons for this support by analysing the Israel/Palestine conflict in terms of Ruman Needs Theory. According to this Theory, humans have essential needs that need to be fulfilled in order to ensure survival and development. Among these needs, the need for identity and recognition of identity is of vital importance. This thesis thus explores the concept of identity as a need, and investigates this need as it relates to inter-group conflict. In situating this theory in the Israel/Palestine conflict, the study exammes how organisations like Ramas have Islamised Palestinian national identity in order to garner political support. The central contention, then, is that the primary identity group of the Palestinian population is no longer nationalist, but Islamic/nationalist. In Islamising the conflict with Israel as well as Palestinian identity, Ramas has been able to justify its often indiscriminate use of violence by appealing to religion. The conflict is thus perceived to be one between two absolutes - that of Islam versus Judaism. In considering the conflict as one of identities struggling for survival in a climate of perceived threat, any attempt at resolution of the conflict needs to include a focus on needs-based issues. The problem-solving approach to negotiation allows for parties to consider issues of identity, recognition and security needs, and thus ensures that the root causes of conflicts are addressed, The contention is that this approach is vital to any conflict resolution strategy where identity needs are at stake, and it provides the grounding for the success of more traditional zero-sum bargaining methods. A recognition of Islamic identity in negotiation processes in Israel/Palestine may thus make for a more comprehensive conflict resolution strategy, and make the outcomes of negotiations more acceptable to the people of Palestine, thus undermining the acceptance of violence that exists at present.
- Full Text:
- Date Issued: 2004
- Authors: De Villiers, Shirley
- Date: 2004
- Subjects: Arab-Israeli conflict Palestinian Arabs -- Civil rights -- Israel Nationalism -- Middle East Religion and politics -- Middle East Jewish-Arab relations Nationalism -- Religious aspects -- Islam -- History -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2873 , http://hdl.handle.net/10962/d1007815
- Description: The use of violence in the Israel/Palestine conflict has been justified and legitimised by an appeal to religion. Militant Islamist organisations like Ramas have become central players in the Palestinian political landscape as a result of the popular support that they enjoy. This thesis aims to investigate the reasons for this support by analysing the Israel/Palestine conflict in terms of Ruman Needs Theory. According to this Theory, humans have essential needs that need to be fulfilled in order to ensure survival and development. Among these needs, the need for identity and recognition of identity is of vital importance. This thesis thus explores the concept of identity as a need, and investigates this need as it relates to inter-group conflict. In situating this theory in the Israel/Palestine conflict, the study exammes how organisations like Ramas have Islamised Palestinian national identity in order to garner political support. The central contention, then, is that the primary identity group of the Palestinian population is no longer nationalist, but Islamic/nationalist. In Islamising the conflict with Israel as well as Palestinian identity, Ramas has been able to justify its often indiscriminate use of violence by appealing to religion. The conflict is thus perceived to be one between two absolutes - that of Islam versus Judaism. In considering the conflict as one of identities struggling for survival in a climate of perceived threat, any attempt at resolution of the conflict needs to include a focus on needs-based issues. The problem-solving approach to negotiation allows for parties to consider issues of identity, recognition and security needs, and thus ensures that the root causes of conflicts are addressed, The contention is that this approach is vital to any conflict resolution strategy where identity needs are at stake, and it provides the grounding for the success of more traditional zero-sum bargaining methods. A recognition of Islamic identity in negotiation processes in Israel/Palestine may thus make for a more comprehensive conflict resolution strategy, and make the outcomes of negotiations more acceptable to the people of Palestine, thus undermining the acceptance of violence that exists at present.
- Full Text:
- Date Issued: 2004
An investigation into the current and potential benefits of tourism-based development in the Albany and Peddie districts
- Authors: Klinkradt, Mary Louise
- Date: 2003 , 2013-05-27
- Subjects: Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4811 , http://hdl.handle.net/10962/d1004904 , Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Description: This research considers the relationship between tourism and development, and how tourism can be used as a means of promoting development. In order to explore this relationship, two districts in the Eastern Cape province of South Africa, the Albany and Peddie Districts have been selected as case study areas. Both the Albany and Peddie Districts are in need of development which can meet the economic and social development of the districts. One such option for the two districts is tourism-based development. This research examines the current status of tourism in both districts through the use of secondary data analysis and primary data gathered from questionnaires and interviews undertaken with tourists and representatives of key stakeholders in the tourism industry. This data was used to establish the current and future potential of tourism in the districts in terms of the availability and diversity of attractions and the tourism assets and facilities in the districts. It was also used to determine whether or not tourism, by promoting infrastructural and economic development, may lead to the socio-economic upliftment of the Albany and Peddie Districts. The results obtained from this research highlight the significant lack of tourism infrastructure in the Peddie District, and the reality that the tourism potential of the district remains untapped. With the marketing and promotion of tourism to the district, and the associated tourist requirements such as accommodation, and other facilities, tourism does hold a potential key to the socio-economic development of the district. The Albany District, however, has a well-established tourism industry, but the development spin-ofts are minimal, and the potential for further tourism-based development in the future would therefore appear to be somewhat limited. A GIS (Geographic Information System) was use to determine and detail possible tourism routes, a final outcome of the investigation being the proposal of two tourism routes to draw people into and through the study area, based on the current assets and attractions of the two districts. These routes highlight one of the options available in the districts to promote much needed development in the two districts through the use of the tourism industry. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Klinkradt, Mary Louise
- Date: 2003 , 2013-05-27
- Subjects: Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4811 , http://hdl.handle.net/10962/d1004904 , Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Description: This research considers the relationship between tourism and development, and how tourism can be used as a means of promoting development. In order to explore this relationship, two districts in the Eastern Cape province of South Africa, the Albany and Peddie Districts have been selected as case study areas. Both the Albany and Peddie Districts are in need of development which can meet the economic and social development of the districts. One such option for the two districts is tourism-based development. This research examines the current status of tourism in both districts through the use of secondary data analysis and primary data gathered from questionnaires and interviews undertaken with tourists and representatives of key stakeholders in the tourism industry. This data was used to establish the current and future potential of tourism in the districts in terms of the availability and diversity of attractions and the tourism assets and facilities in the districts. It was also used to determine whether or not tourism, by promoting infrastructural and economic development, may lead to the socio-economic upliftment of the Albany and Peddie Districts. The results obtained from this research highlight the significant lack of tourism infrastructure in the Peddie District, and the reality that the tourism potential of the district remains untapped. With the marketing and promotion of tourism to the district, and the associated tourist requirements such as accommodation, and other facilities, tourism does hold a potential key to the socio-economic development of the district. The Albany District, however, has a well-established tourism industry, but the development spin-ofts are minimal, and the potential for further tourism-based development in the future would therefore appear to be somewhat limited. A GIS (Geographic Information System) was use to determine and detail possible tourism routes, a final outcome of the investigation being the proposal of two tourism routes to draw people into and through the study area, based on the current assets and attractions of the two districts. These routes highlight one of the options available in the districts to promote much needed development in the two districts through the use of the tourism industry. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
The development of a baculovirus expression system for the production of Helicoverpa armigera stunt virus capsids for use in the encapsidation of foreign molecules
- Mosisili, Kekeletso Mpho Thakane
- Authors: Mosisili, Kekeletso Mpho Thakane
- Date: 2003
- Subjects: Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4088 , http://hdl.handle.net/10962/d1007700 , Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Description: The capsid protein of Helicoverpa armigera stunt virus (HaSV) a T=4 insect virus was expressed in Spodoptera frugiperda 9 cells using a baculovirus vector. When the insect cells were infected at a high MOl the expressed coat protein assembled into virus-like particles (VLPs) that spontaneously underwent maturation and were morphologically indistinguishable from wild-type HaSV. The VLPs were electron dense when viewed under EM and encapsidated their coat protein mRNA. When Sf9 cells were infected at a low multiplicity of infection (MOl) the expressed capsid protein assembled into procapsids that did not spontaneously undergo maturation. These procapsids underwent autoproteolytic maturation cleavage when they were treated with an acidic buffer. The procapsids were used in the encapsidation of a FITC labelled peptide. The peptide encapsidating VLPs showed an increase in their buoyant density that was not collaborated by an increase in the concentration of the FITC labelled peptide detected when these samples were compared to control samples with similar buoyant densities.
- Full Text:
- Date Issued: 2003
- Authors: Mosisili, Kekeletso Mpho Thakane
- Date: 2003
- Subjects: Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4088 , http://hdl.handle.net/10962/d1007700 , Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Description: The capsid protein of Helicoverpa armigera stunt virus (HaSV) a T=4 insect virus was expressed in Spodoptera frugiperda 9 cells using a baculovirus vector. When the insect cells were infected at a high MOl the expressed coat protein assembled into virus-like particles (VLPs) that spontaneously underwent maturation and were morphologically indistinguishable from wild-type HaSV. The VLPs were electron dense when viewed under EM and encapsidated their coat protein mRNA. When Sf9 cells were infected at a low multiplicity of infection (MOl) the expressed capsid protein assembled into procapsids that did not spontaneously undergo maturation. These procapsids underwent autoproteolytic maturation cleavage when they were treated with an acidic buffer. The procapsids were used in the encapsidation of a FITC labelled peptide. The peptide encapsidating VLPs showed an increase in their buoyant density that was not collaborated by an increase in the concentration of the FITC labelled peptide detected when these samples were compared to control samples with similar buoyant densities.
- Full Text:
- Date Issued: 2003
South African women's literature and the ecofeminist perspective
- Authors: Ewing, Maureen Colleen
- Date: 2013-05-24
- Subjects: Ecofeminism in literature Ecology in literature Nature in literature South African fiction -- History and criticism Smith, Pauline, 1883-1959 Schreiner, Olive, 1855-1920 Matthee, Dalene, 1938-2005 Poland, Marguerite
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2287 , http://hdl.handle.net/10962/d1007808
- Description: A social-constructionist ecofeminist perspective argues that patriarchal society separates the human (or culture) from nature, which causes a false assumption that humanity possesses the right, as a superior species, to dominate nature. This perspective integrates the domination of nature with social conflicts, including but not limited to racial discrimination, gender oppression, and class hierarchies. Understanding how these various forms of oppression interrelate forms the main goal of an ecofeminist perspective. Since the nature-culture, female-male, and whitenonwhite conflicts resonate and interlock throughout South Africa's history, socialconstructionist ecofeminism is an indispensable perspective for analysing South African literature. This thesis takes a social-constructionist ecofeminist approach and applies it to four women authors that write about South African society between the years 1860-1900. This thesis includes the following authors and their works: Olive Schreiner (1855-1920) and two of her novels, The Story of an African Farm (1883) and From Man to Man (published posthumously in 1927); Pauline Smith (1882-1959) and her novel The Beadle (1926); Dalene Matthee (1938- ) and three of her novels, Circles in a Forest (1984), Fiela's Child (1986), and The Mulberry Forest (1987); and Marguerite Poland (1950- ) and one of her novels, Shades (1993). This thesis investigates two women from the time period (Schreiner and Smith) and two women from a late twentieth century perspective (Matthee and Poland) and compares how they depict the natural environment, how they construct gender, and how they interpret class and race power struggles. This thesis concludes that the social-constructionist perspective offers unique insights into these four authors. Schreiner's novels reveal her concerns about gender and racial conflicts in South Africa and her understanding of the nature-culture dichotomy as sustained by Social Darwinism. Smith offers insights into the complex power structures in a rural Afrikaans society that keep women and nonwhite races silent. Matthee writes nature as an active participant in her novels; the social and ecological conflicts emphasise the transformation of the Knysna area. Poland explores the racial tensions, gender conflicts, and environmental concerns that preceded the South African War. Schreiner, Smith, Matthee, and Poland make up a small cross-section of South African literature, but they provide a basis for further discussing the ecofeminist perspective within a South African context. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Ewing, Maureen Colleen
- Date: 2013-05-24
- Subjects: Ecofeminism in literature Ecology in literature Nature in literature South African fiction -- History and criticism Smith, Pauline, 1883-1959 Schreiner, Olive, 1855-1920 Matthee, Dalene, 1938-2005 Poland, Marguerite
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2287 , http://hdl.handle.net/10962/d1007808
- Description: A social-constructionist ecofeminist perspective argues that patriarchal society separates the human (or culture) from nature, which causes a false assumption that humanity possesses the right, as a superior species, to dominate nature. This perspective integrates the domination of nature with social conflicts, including but not limited to racial discrimination, gender oppression, and class hierarchies. Understanding how these various forms of oppression interrelate forms the main goal of an ecofeminist perspective. Since the nature-culture, female-male, and whitenonwhite conflicts resonate and interlock throughout South Africa's history, socialconstructionist ecofeminism is an indispensable perspective for analysing South African literature. This thesis takes a social-constructionist ecofeminist approach and applies it to four women authors that write about South African society between the years 1860-1900. This thesis includes the following authors and their works: Olive Schreiner (1855-1920) and two of her novels, The Story of an African Farm (1883) and From Man to Man (published posthumously in 1927); Pauline Smith (1882-1959) and her novel The Beadle (1926); Dalene Matthee (1938- ) and three of her novels, Circles in a Forest (1984), Fiela's Child (1986), and The Mulberry Forest (1987); and Marguerite Poland (1950- ) and one of her novels, Shades (1993). This thesis investigates two women from the time period (Schreiner and Smith) and two women from a late twentieth century perspective (Matthee and Poland) and compares how they depict the natural environment, how they construct gender, and how they interpret class and race power struggles. This thesis concludes that the social-constructionist perspective offers unique insights into these four authors. Schreiner's novels reveal her concerns about gender and racial conflicts in South Africa and her understanding of the nature-culture dichotomy as sustained by Social Darwinism. Smith offers insights into the complex power structures in a rural Afrikaans society that keep women and nonwhite races silent. Matthee writes nature as an active participant in her novels; the social and ecological conflicts emphasise the transformation of the Knysna area. Poland explores the racial tensions, gender conflicts, and environmental concerns that preceded the South African War. Schreiner, Smith, Matthee, and Poland make up a small cross-section of South African literature, but they provide a basis for further discussing the ecofeminist perspective within a South African context. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
Biology and demography of the spotted grunter Pomadasys commersonnii (Haemulidae) in South African waters
- Authors: Webb, Garth Anthony
- Date: 2003
- Subjects: Grunts (Fishes) -- South Africa , Grunts (Fishes) -- South Africa -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5201 , http://hdl.handle.net/10962/d1003727 , Grunts (Fishes) -- South Africa , Grunts (Fishes) -- South Africa -- Ecology
- Description: The spotted grunter, Pomadasys commersonnii (Haemulidae), is an Indian Ocean coastal species, extending from India to False Bay but is absent from the central Indian Ocean islands. Its taste and texture has made it one of the most important line fish species and is caught by recreational and subsistence fisherman along the entire east coast of South Africa. Because of its inshore distribution, reduced catch rates and estuarine dependence the species was de-commercialised in 1992. Since then it has been investigated as a candidate species for mariculture. All previous work on the biology of the species was undertaken on fish collected in KwaZulu-Natal in the mid 1970's. All other information has been incidental and formed part of other ecological studies. All management plans for this species have been based on these data. To develop a more comprehensive management plan that incorporates the entire population of spotted grunter, it was deemed necessary to reassess the biology (including feeding biology, age and growth and reproductive biology) as well as the demography of the population throughout its distributional range in South African waters. Analysis of the diet of spotted grunter, collected in estuaries, indicates that crustaceans form the bulk of the prey selected. Amphipods, mysids and estuarine brachyura predominate the diet of fish < 300 mm TL. At 200 mm TL fish start to prey on anomurans, which are extracted from their burrows using the 'blowing' feeding mechanism. Anomurans, in particular Upogebia africana and Callianassa krausii, become the preferred prey of fish larger than 300 mm TL. The high degree of diet flexibility that spotted grunter exhibit means that the composition and abundance of the macrobenthos of a particular environment will dictate the diet of the species. Otolith growth zones were found to be deposited annually with the opaque zones being deposited during the austral summer (November - February). The optical definition of annual otolith growth rings differed significantly between geographic regions (namely: Western Cape, South Eastern Cape and KwaZulu-Natal). Growth (sex combined) offish in the Western Cape were best described by the specialised 3 parameter Von Bertalanffy with a relative error structure in the form : Lt = 753(1- e⁻°·¹⁵⁴ ⁽t +¹·⁶¹⁵⁾) while growth in the South Eastern Cape was best described by using the Schnute model with an absolute error structure in the form: Lt=177°·⁴¹⁶ + (676.2⁻¹·²⁶⁶ - 169.2⁻¹²⁶⁶)[1-e°·⁴¹⁶⁽t-t₁⁾ / 1-e°·⁴¹⁶⁽t₂-t₁⁾]¹/¹·²⁶⁶ whereas growth was best described in KwaZulu-Natal using the specialised 3 parameter Von Bertalanffy with a relative error structure in the form: Lt = 839(1-e°·¹⁷⁽t⁺°·⁴⁹⁾) In the South Eastern Cape, length at 50% maturity was found to be 305 mm TL for males. Since females with ripe & running or spent gonads were not found in the South Eastern Cape and since histological evidence suggests that females in the South Eastern Cape have spawned, it appears that spawning does not occur in the South Eastern Cape. These results suggest that adults are resident in the estuaries of the Western and South Eastern Cape and undertake the spring/summer, northward spawning migration to KwaZulu-Natal. After joining the resident spawner stock in KwaZulu-Natal and spawning in the offshore environment of KwaZulu-Natal, adults soon return to the southern regions of their distributional range. Juveniles recruit into KwaZulu-Natal estuaries at a length of 25 - 35 mm TL. A proportion of the eggs and larvae are transported southwards along the periphery of the western boundary Agulhas Current where juveniles (25 - 30 mm TL) recruit into the estuaries as far south as the Swartvlei estuary in the Western Cape. There is evidence to suggest that the fish, which occur in the Western Cape estuaries, have migrated there once they have attained sexual maturity further east.
- Full Text:
- Date Issued: 2003
- Authors: Webb, Garth Anthony
- Date: 2003
- Subjects: Grunts (Fishes) -- South Africa , Grunts (Fishes) -- South Africa -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5201 , http://hdl.handle.net/10962/d1003727 , Grunts (Fishes) -- South Africa , Grunts (Fishes) -- South Africa -- Ecology
- Description: The spotted grunter, Pomadasys commersonnii (Haemulidae), is an Indian Ocean coastal species, extending from India to False Bay but is absent from the central Indian Ocean islands. Its taste and texture has made it one of the most important line fish species and is caught by recreational and subsistence fisherman along the entire east coast of South Africa. Because of its inshore distribution, reduced catch rates and estuarine dependence the species was de-commercialised in 1992. Since then it has been investigated as a candidate species for mariculture. All previous work on the biology of the species was undertaken on fish collected in KwaZulu-Natal in the mid 1970's. All other information has been incidental and formed part of other ecological studies. All management plans for this species have been based on these data. To develop a more comprehensive management plan that incorporates the entire population of spotted grunter, it was deemed necessary to reassess the biology (including feeding biology, age and growth and reproductive biology) as well as the demography of the population throughout its distributional range in South African waters. Analysis of the diet of spotted grunter, collected in estuaries, indicates that crustaceans form the bulk of the prey selected. Amphipods, mysids and estuarine brachyura predominate the diet of fish < 300 mm TL. At 200 mm TL fish start to prey on anomurans, which are extracted from their burrows using the 'blowing' feeding mechanism. Anomurans, in particular Upogebia africana and Callianassa krausii, become the preferred prey of fish larger than 300 mm TL. The high degree of diet flexibility that spotted grunter exhibit means that the composition and abundance of the macrobenthos of a particular environment will dictate the diet of the species. Otolith growth zones were found to be deposited annually with the opaque zones being deposited during the austral summer (November - February). The optical definition of annual otolith growth rings differed significantly between geographic regions (namely: Western Cape, South Eastern Cape and KwaZulu-Natal). Growth (sex combined) offish in the Western Cape were best described by the specialised 3 parameter Von Bertalanffy with a relative error structure in the form : Lt = 753(1- e⁻°·¹⁵⁴ ⁽t +¹·⁶¹⁵⁾) while growth in the South Eastern Cape was best described by using the Schnute model with an absolute error structure in the form: Lt=177°·⁴¹⁶ + (676.2⁻¹·²⁶⁶ - 169.2⁻¹²⁶⁶)[1-e°·⁴¹⁶⁽t-t₁⁾ / 1-e°·⁴¹⁶⁽t₂-t₁⁾]¹/¹·²⁶⁶ whereas growth was best described in KwaZulu-Natal using the specialised 3 parameter Von Bertalanffy with a relative error structure in the form: Lt = 839(1-e°·¹⁷⁽t⁺°·⁴⁹⁾) In the South Eastern Cape, length at 50% maturity was found to be 305 mm TL for males. Since females with ripe & running or spent gonads were not found in the South Eastern Cape and since histological evidence suggests that females in the South Eastern Cape have spawned, it appears that spawning does not occur in the South Eastern Cape. These results suggest that adults are resident in the estuaries of the Western and South Eastern Cape and undertake the spring/summer, northward spawning migration to KwaZulu-Natal. After joining the resident spawner stock in KwaZulu-Natal and spawning in the offshore environment of KwaZulu-Natal, adults soon return to the southern regions of their distributional range. Juveniles recruit into KwaZulu-Natal estuaries at a length of 25 - 35 mm TL. A proportion of the eggs and larvae are transported southwards along the periphery of the western boundary Agulhas Current where juveniles (25 - 30 mm TL) recruit into the estuaries as far south as the Swartvlei estuary in the Western Cape. There is evidence to suggest that the fish, which occur in the Western Cape estuaries, have migrated there once they have attained sexual maturity further east.
- Full Text:
- Date Issued: 2003
Metal interactions with neural substrates and their role in neurodegeneration
- Authors: Lack, Barbara Anne
- Date: 2003
- Subjects: Nervous system -- Degeneration Neurotoxicology Chemical reactions Metals -- Physiological effect Melatonin -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4391 , http://hdl.handle.net/10962/d1005709
- Description: "Life" may be characterized as a controlled stationary flow equilibrium, maintained by energy consuming chemical reactions. The physiological functioning of these life systems include at least 28 of the elements isolated on the periodic table thus far, most of which are metals. However, as with Paracelsus Principle: "The dose makes the poison", there exists a definite link between metal levels, essential and toxic, and the onset of neurodegenerative diseases. The economic costs of brain dysfunction are enormous, but this pales in comparison to the staggering emotional toll on the victims themselves and their families. In an attempt to improve the understanding of the causes of neurodegeneration, this study focuses on one potential aspect: the possible link between metals and neurotransmitter homeostasis utilising a variety of electronanalytical techniques. Adsorptive cathodic stripping voltammetry was employed to investigate the binding affinities and complex formation of melatonin and its precursor serotonin with calcium, potassium, sodium, lithium and aluminium. The results showed that all the metals studied formed complexes with both pineal indoleamines. However, the stability and affmity of the ligands toward the various metals varied greatly. The study suggests a further role for melatonin, that of metalloregulator and possible metal detoxifier in the brain, the in vivo studies which followed will further substantiate this notion. This research additionally focused on the cholinergic system, in particular acetylcholine complex formation studies with mercury, lead, cadmium, copper and zinc using the adsorptive cathodic stripping voltammetry method. The formation and characterisation of a solid mercury-acetylcholine complex lent further strength to the in situ electrochemical complex formation observed. The results showed the preference of acetylcholine for environmentally toxic heavy metals (such as Cd²⁺) over those divalent cations that occur naturally in the body. The possible metalloregulatory role melatonin played in the three brain regIOns: cerebellum, cortex and corpus striatum of male Wistar rats was studied as an in vivo extension of the earlier in vitro studies. Anodic stripping voltammetry was employed to detect metal levels present. The results showed that daily injections of melatonin was responsible for significantly decreasing copper(I), cadmium(II) and lead(II) levels in various regions of the rat brain of those animals that had undergone a pinealectomy in comparison to the saline injected group having undergone the same treatment. Histological and electrochemical stripping techniques were applied to investigate the implications of high A1³⁺ levels in the brain regions, particularly the hippocampus. Melatonin showed signs of promise in indirect symptom alleviation and by significantly decreasing A1³⁺ levels in rats that had been dosed with melatonin prior to A1³⁺ treatments in comparison with the control groups. Finally a preliminary study outlining a method for the production of a calcium selective microelectrode was undertaken. Further work is still needed to optimise the microelectrode production as well as its possible applications. However, whilst the overall conclusions of this entire multidisciplinary study may indeed only be in effect one piece of a very large puzzle on neurodegenerative diseases, this piece will no doubt serve as a building block for further ideas and work in this field.
- Full Text:
- Date Issued: 2003
- Authors: Lack, Barbara Anne
- Date: 2003
- Subjects: Nervous system -- Degeneration Neurotoxicology Chemical reactions Metals -- Physiological effect Melatonin -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4391 , http://hdl.handle.net/10962/d1005709
- Description: "Life" may be characterized as a controlled stationary flow equilibrium, maintained by energy consuming chemical reactions. The physiological functioning of these life systems include at least 28 of the elements isolated on the periodic table thus far, most of which are metals. However, as with Paracelsus Principle: "The dose makes the poison", there exists a definite link between metal levels, essential and toxic, and the onset of neurodegenerative diseases. The economic costs of brain dysfunction are enormous, but this pales in comparison to the staggering emotional toll on the victims themselves and their families. In an attempt to improve the understanding of the causes of neurodegeneration, this study focuses on one potential aspect: the possible link between metals and neurotransmitter homeostasis utilising a variety of electronanalytical techniques. Adsorptive cathodic stripping voltammetry was employed to investigate the binding affinities and complex formation of melatonin and its precursor serotonin with calcium, potassium, sodium, lithium and aluminium. The results showed that all the metals studied formed complexes with both pineal indoleamines. However, the stability and affmity of the ligands toward the various metals varied greatly. The study suggests a further role for melatonin, that of metalloregulator and possible metal detoxifier in the brain, the in vivo studies which followed will further substantiate this notion. This research additionally focused on the cholinergic system, in particular acetylcholine complex formation studies with mercury, lead, cadmium, copper and zinc using the adsorptive cathodic stripping voltammetry method. The formation and characterisation of a solid mercury-acetylcholine complex lent further strength to the in situ electrochemical complex formation observed. The results showed the preference of acetylcholine for environmentally toxic heavy metals (such as Cd²⁺) over those divalent cations that occur naturally in the body. The possible metalloregulatory role melatonin played in the three brain regIOns: cerebellum, cortex and corpus striatum of male Wistar rats was studied as an in vivo extension of the earlier in vitro studies. Anodic stripping voltammetry was employed to detect metal levels present. The results showed that daily injections of melatonin was responsible for significantly decreasing copper(I), cadmium(II) and lead(II) levels in various regions of the rat brain of those animals that had undergone a pinealectomy in comparison to the saline injected group having undergone the same treatment. Histological and electrochemical stripping techniques were applied to investigate the implications of high A1³⁺ levels in the brain regions, particularly the hippocampus. Melatonin showed signs of promise in indirect symptom alleviation and by significantly decreasing A1³⁺ levels in rats that had been dosed with melatonin prior to A1³⁺ treatments in comparison with the control groups. Finally a preliminary study outlining a method for the production of a calcium selective microelectrode was undertaken. Further work is still needed to optimise the microelectrode production as well as its possible applications. However, whilst the overall conclusions of this entire multidisciplinary study may indeed only be in effect one piece of a very large puzzle on neurodegenerative diseases, this piece will no doubt serve as a building block for further ideas and work in this field.
- Full Text:
- Date Issued: 2003
Putting participatory communication into practice through community radio: a case study of how policies on programming and production are formulated and implemented at Radio Graaff-Reinet
- Kanyegirire, Andrew Steve Tumuhirwe
- Authors: Kanyegirire, Andrew Steve Tumuhirwe
- Date: 2003
- Subjects: Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3442 , http://hdl.handle.net/10962/d1002896 , Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Description: In the South African (SA) model of community radio, listeners are expected to be in charge of the management and programming operations of stations. This study tests the SA model against the actual conditions at an existing station. For this purpose, the study focuses on Radio Graaff-Reinet, a community radio station in the Eastern Cape. Emphasis is on examining the extent to which members of the station’s target community are involved in its operations. The study first assesses the nature of this involvement, keeping in mind the principles of, ‘community ownership’ and ‘participatory programming’ on which the SA model of community radio is based. It is argued that the station does provide a valuable ‘public sphere’ for its listeners. The potential of this sphere remains limited, however, due to the impact of ongoing power struggles around the ownership of the station. The lack of proper systems for managing these struggles has contributed to the fact that the station continues to be in a constant state of flux, with a high turnover of staff and regular changes in its policies and strategies. The study argues that, until such systems are put in place, the principles of community ownership will not be fully realizable. Areas in which the struggle over ownership plays itself out can be identified in the relationship between the station’s Board of Directors and its managing staff, between one particular station manager and her staff and between the station and its target community. These struggles often take place in context of a debate about the financial sustainability of the station versus its developmental aims. It is argued that this opposition needs to be questioned since, until the station is financially stable, it will remain vulnerable to interference by powerful individuals and groups in its attempts to establish such developmental aims. The study then goes on to identify key weaknesses in the station’s approach to community ownership and participation. In particular, it is pointed out that various stakeholders in the station have contradictory understandings of what is meant by ‘community’, using the term to include or exclude sections of the Graaff-Reinet society in very different ways. There are also very different understandings at play about the concept of community radio itself. These contradictions have an impact on the station’s ability to implement participatory programming. This situation is exacerbated by the fact that the station does not have a consistent forum in which shared decision-making can take place. Consequently, the station also remains unable to draw effectively on its own volunteer staff and on its community as resources for programming content. Finally, the study explores the broader significance of the weaknesses that exist in the case of Graaff-Reinet, arguing that these are problems that repeat themselves throughout the South African community radio sector. Possible strategies for addressing these problems are suggested, including approaches to monitoring and research, training, organizational development and advocacy.
- Full Text:
- Date Issued: 2003
- Authors: Kanyegirire, Andrew Steve Tumuhirwe
- Date: 2003
- Subjects: Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3442 , http://hdl.handle.net/10962/d1002896 , Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Description: In the South African (SA) model of community radio, listeners are expected to be in charge of the management and programming operations of stations. This study tests the SA model against the actual conditions at an existing station. For this purpose, the study focuses on Radio Graaff-Reinet, a community radio station in the Eastern Cape. Emphasis is on examining the extent to which members of the station’s target community are involved in its operations. The study first assesses the nature of this involvement, keeping in mind the principles of, ‘community ownership’ and ‘participatory programming’ on which the SA model of community radio is based. It is argued that the station does provide a valuable ‘public sphere’ for its listeners. The potential of this sphere remains limited, however, due to the impact of ongoing power struggles around the ownership of the station. The lack of proper systems for managing these struggles has contributed to the fact that the station continues to be in a constant state of flux, with a high turnover of staff and regular changes in its policies and strategies. The study argues that, until such systems are put in place, the principles of community ownership will not be fully realizable. Areas in which the struggle over ownership plays itself out can be identified in the relationship between the station’s Board of Directors and its managing staff, between one particular station manager and her staff and between the station and its target community. These struggles often take place in context of a debate about the financial sustainability of the station versus its developmental aims. It is argued that this opposition needs to be questioned since, until the station is financially stable, it will remain vulnerable to interference by powerful individuals and groups in its attempts to establish such developmental aims. The study then goes on to identify key weaknesses in the station’s approach to community ownership and participation. In particular, it is pointed out that various stakeholders in the station have contradictory understandings of what is meant by ‘community’, using the term to include or exclude sections of the Graaff-Reinet society in very different ways. There are also very different understandings at play about the concept of community radio itself. These contradictions have an impact on the station’s ability to implement participatory programming. This situation is exacerbated by the fact that the station does not have a consistent forum in which shared decision-making can take place. Consequently, the station also remains unable to draw effectively on its own volunteer staff and on its community as resources for programming content. Finally, the study explores the broader significance of the weaknesses that exist in the case of Graaff-Reinet, arguing that these are problems that repeat themselves throughout the South African community radio sector. Possible strategies for addressing these problems are suggested, including approaches to monitoring and research, training, organizational development and advocacy.
- Full Text:
- Date Issued: 2003
Rhodes University Graduation Ceremony 2003
- Authors: Rhodes University
- Date: 2003
- Language: English
- Type: text
- Identifier: vital:8144 , http://hdl.handle.net/10962/d1007264
- Description: Rhodes University Graduation Ceremonies [at] 1820 Settlers National Monument Friday, 11 April 2003 at 10:30; 14:30 & 18:00 [and] Saturday, 12 April at 10:30 , Graduation Ceremony Christian Centre, Wyse Street, East London Friday, 9 May 2003 at 18:00 [and] Saturday, 10 May 2003 at 10:30
- Full Text:
- Date Issued: 2003
- Authors: Rhodes University
- Date: 2003
- Language: English
- Type: text
- Identifier: vital:8144 , http://hdl.handle.net/10962/d1007264
- Description: Rhodes University Graduation Ceremonies [at] 1820 Settlers National Monument Friday, 11 April 2003 at 10:30; 14:30 & 18:00 [and] Saturday, 12 April at 10:30 , Graduation Ceremony Christian Centre, Wyse Street, East London Friday, 9 May 2003 at 18:00 [and] Saturday, 10 May 2003 at 10:30
- Full Text:
- Date Issued: 2003
An entrepreneurial framework for deciding on the implementation of large format digital printing internationally
- Adendorff, Christian Michael
- Authors: Adendorff, Christian Michael
- Date: 2003
- Subjects: Entrepreneurship , Success in business , Business -- Technological innovations , Digital printing
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1169 , http://hdl.handle.net/10962/d1002785 , Entrepreneurship , Success in business , Business -- Technological innovations , Digital printing
- Description: This study focuses on entrepreneurs within the SME sector using large format digital printing (LFDP) because of the changes in technology that influences the decisionmaking processes of the entrepreneur in the purchasing of a new LFDP. These fast changes are likely to continue and can cause technologies to become obsolete overnight. The entrepreneurs within the LFDP industry find themselves in the midst of these fast changes and are faced with a dilemma. On the one hand, they need to make sure that the technology used produces consistent and quality products. On the other hand, the entrepreneur needs to ensure an optimal return on investments. From the literature and the findings of the study, the researcher recommends a change to an existing model on a consultant involvement purchase of high technology products, which is then adapted to integrate resource-forecasting areas together with timing and type of information required as well as external environment scanning. The existing model’s focus is on the individual’s ability to make decisions based on their own knowledge. However, by integrating technology forecasting components, and scanning the business environment and resource forecasting needed the decision-maker will be better equipped to make decisions that also takes into account the external environment. This will also allow them to plan and manage growth in a systematic way. Therefore the proposed model takes into account individual capabilities and technology forecasting components that can facilitate the decision-making process. The adapted model on decision-making clearly delineates that the combination of entrepreneurial qualities and technology forecasting techniques in the LFDP industry will ultimately assist the entrepreneur on various levels in deciding on a new LFDP.
- Full Text:
- Date Issued: 2003
- Authors: Adendorff, Christian Michael
- Date: 2003
- Subjects: Entrepreneurship , Success in business , Business -- Technological innovations , Digital printing
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1169 , http://hdl.handle.net/10962/d1002785 , Entrepreneurship , Success in business , Business -- Technological innovations , Digital printing
- Description: This study focuses on entrepreneurs within the SME sector using large format digital printing (LFDP) because of the changes in technology that influences the decisionmaking processes of the entrepreneur in the purchasing of a new LFDP. These fast changes are likely to continue and can cause technologies to become obsolete overnight. The entrepreneurs within the LFDP industry find themselves in the midst of these fast changes and are faced with a dilemma. On the one hand, they need to make sure that the technology used produces consistent and quality products. On the other hand, the entrepreneur needs to ensure an optimal return on investments. From the literature and the findings of the study, the researcher recommends a change to an existing model on a consultant involvement purchase of high technology products, which is then adapted to integrate resource-forecasting areas together with timing and type of information required as well as external environment scanning. The existing model’s focus is on the individual’s ability to make decisions based on their own knowledge. However, by integrating technology forecasting components, and scanning the business environment and resource forecasting needed the decision-maker will be better equipped to make decisions that also takes into account the external environment. This will also allow them to plan and manage growth in a systematic way. Therefore the proposed model takes into account individual capabilities and technology forecasting components that can facilitate the decision-making process. The adapted model on decision-making clearly delineates that the combination of entrepreneurial qualities and technology forecasting techniques in the LFDP industry will ultimately assist the entrepreneur on various levels in deciding on a new LFDP.
- Full Text:
- Date Issued: 2003
Binding and transcriptional activation by Uga3p, a zinc binuclear cluster protein of Saccharomyces cerevisiae redefining the UAS [subscript GABA] and the Uga3p binding site
- Authors: Idicula, Anu Mary
- Date: 2003
- Subjects: Saccharomyces cerevisiae GABA
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3933 , http://hdl.handle.net/10962/d1003992
- Description: Uga3p, a member of the zinc binuclear cluster transcription factor family, is required for [gamma]-aminobutyric acid-dependent transcription of the UGA genes in Saccharomyces cerevisiae. Crystallographic data of some of the protein-DNA complexes of this family reveal that members of this family bind to CGG triplets. A conserved 19-nucleotide activation element in certain UGA gene promoter regions contains a CCG-N4-CGG everted repeat, proposed to be the binding site of Uga3p, UAS[subscript GABA]. The spacer region (N4) between the CGG triplets has been suggested to be the specificity determinant for binding to UAS[subscript GABA]. The data available from the Saccharomyces genome database indicates that there are multiple repeats of -CCG-N4-CGG- regions within the genome. These transcription factors are involved in the activation of specific pathways and the question arises as to how their specificity of binding is determined. The aim of this study was to understand the binding characteristics of Uga3p to UAS[subscript GABA] and to determine the affinity and specificity of this interaction. In this study, full-length (tagged and untagged) and truncated (1-124 a.a.) Uga3p was produced in a heterologous expression system (E. coli). The interaction of Uga3p with UAS[subscript GABA] in Saccharomyces cerevisiae was characterized in terms of binding in vitro and the transcriptional activation of lacZ reporter genes in vivo. The Uga3p was capable of binding to these sites in vitro independent of exogenous GABA. Electrophoretic mobility shift assays (EMSA) of the full-length Uga3p with the wild type UAS[subscript GABA] sequences produced two distinct mobility complexes. The complexes formed in the EMSA of the full-length Uga3p were those specific to the interaction of the Uga3p to UAS[subscript GABA]. The truncated Uga3p(1-124 a.a.), which has the DNA-binding zinc cluster domain, the linker region and the putative coiled-coil domain was not functionally equivalent to the full-length protein with respect to binding in vitro because the EMSAs of the UAS[subscript GABA] with the truncated Uga3p produced indistinct complexes. EMSAs using mutant UAS[subscript GABA] sequences and heterologously-produced full-length Uga3p, demonstrated that UAS[subscript GABA] consists of two, independent Uga3p-binding sites. This work presents evidence that the two Uga3p molecules bound to UAS[subscript GABA] most likely interact with each other. Unlike other zinc cluster binding sites the Uga3p-binding site is an asymmetric site of 5’-SGCGGNWWT-3’ (S= G or C, W = A or T and N = no nucleotide or G or C). UAS[subscript GABA] is a palindrome containing the two asymmetric Uga3p-binding sites. The two-site consensus sequence required for the binding of Uga3p to the UAS[subscript GABA] is present upstream of UGA1 (region -387 to -370) and UGA4 (region -403 to -387). Furthermore, a single Uga3p-binding site was identified in the 5’ untranslated regions of UGA2 (region -219 to -211). GABA-dependent transcriptional activation by UAS[subscript GABA] in vivo could be directly correlated to a high affinity, specific interaction of two Uga3p molecules to this UAS. Binding with high affinity required the conserved sequences flanking the everted repeat. This study provided evidence that the binding pattern of Uga3p is novel compared to other zinc cluster motifs investigated, as the sequences flanking the everted repeat are important regions for recognition by Uga3p. The studies with the truncated Uga3p (1 –124 a.a.), also suggested that the regions C-terminal to the DNA-binding motif and putative coiled-coil area of this protein are important for Uga3p-specific interactions with UAS[subscript GABA]. Investigation of regions C-terminal to the zinc cluster, linker and putative coiledcoil revealed an eight-motif regulatory region similar to that in other zinc cluster proteins. This indicated that the regions C-terminal to these domains are important for the regulation and activity of these proteins. A putative seven repeat WD40-like motif was identified within this region. This putative domain has been speculated to be important for protein-protein interactions. Phosphorylation and dephosphorylation in other proteins of this class have been indicated to be important for the regulation of the activity of these proteins. The bioinformatic analysis of Uga3p revealed two possible cAMP/cGMP-dependent protein kinase phosphorylation sites, four putative protein kinase C phosphorylation motifs and four putative casein kinase II phosphorylation motifs. This study has contributed to the understanding of the nature of interactions between Uga3p and its specific UAS [subscript GABA] and how the regions flanking the everted repeat determine its specificity. The comparison of the nature of the binding of truncated and full-length Uga3p in vitro provided evidence for the role played by the full-length protein in determining this specific interaction. This evidence suggested that the in vitro binding evidence for other proteins of this family, using truncated peptides that carry the DNA-binding domain, might not reflect the true nature of interactions between the proteins of this class and their specific UASs in vivo.
- Full Text:
- Date Issued: 2003
- Authors: Idicula, Anu Mary
- Date: 2003
- Subjects: Saccharomyces cerevisiae GABA
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3933 , http://hdl.handle.net/10962/d1003992
- Description: Uga3p, a member of the zinc binuclear cluster transcription factor family, is required for [gamma]-aminobutyric acid-dependent transcription of the UGA genes in Saccharomyces cerevisiae. Crystallographic data of some of the protein-DNA complexes of this family reveal that members of this family bind to CGG triplets. A conserved 19-nucleotide activation element in certain UGA gene promoter regions contains a CCG-N4-CGG everted repeat, proposed to be the binding site of Uga3p, UAS[subscript GABA]. The spacer region (N4) between the CGG triplets has been suggested to be the specificity determinant for binding to UAS[subscript GABA]. The data available from the Saccharomyces genome database indicates that there are multiple repeats of -CCG-N4-CGG- regions within the genome. These transcription factors are involved in the activation of specific pathways and the question arises as to how their specificity of binding is determined. The aim of this study was to understand the binding characteristics of Uga3p to UAS[subscript GABA] and to determine the affinity and specificity of this interaction. In this study, full-length (tagged and untagged) and truncated (1-124 a.a.) Uga3p was produced in a heterologous expression system (E. coli). The interaction of Uga3p with UAS[subscript GABA] in Saccharomyces cerevisiae was characterized in terms of binding in vitro and the transcriptional activation of lacZ reporter genes in vivo. The Uga3p was capable of binding to these sites in vitro independent of exogenous GABA. Electrophoretic mobility shift assays (EMSA) of the full-length Uga3p with the wild type UAS[subscript GABA] sequences produced two distinct mobility complexes. The complexes formed in the EMSA of the full-length Uga3p were those specific to the interaction of the Uga3p to UAS[subscript GABA]. The truncated Uga3p(1-124 a.a.), which has the DNA-binding zinc cluster domain, the linker region and the putative coiled-coil domain was not functionally equivalent to the full-length protein with respect to binding in vitro because the EMSAs of the UAS[subscript GABA] with the truncated Uga3p produced indistinct complexes. EMSAs using mutant UAS[subscript GABA] sequences and heterologously-produced full-length Uga3p, demonstrated that UAS[subscript GABA] consists of two, independent Uga3p-binding sites. This work presents evidence that the two Uga3p molecules bound to UAS[subscript GABA] most likely interact with each other. Unlike other zinc cluster binding sites the Uga3p-binding site is an asymmetric site of 5’-SGCGGNWWT-3’ (S= G or C, W = A or T and N = no nucleotide or G or C). UAS[subscript GABA] is a palindrome containing the two asymmetric Uga3p-binding sites. The two-site consensus sequence required for the binding of Uga3p to the UAS[subscript GABA] is present upstream of UGA1 (region -387 to -370) and UGA4 (region -403 to -387). Furthermore, a single Uga3p-binding site was identified in the 5’ untranslated regions of UGA2 (region -219 to -211). GABA-dependent transcriptional activation by UAS[subscript GABA] in vivo could be directly correlated to a high affinity, specific interaction of two Uga3p molecules to this UAS. Binding with high affinity required the conserved sequences flanking the everted repeat. This study provided evidence that the binding pattern of Uga3p is novel compared to other zinc cluster motifs investigated, as the sequences flanking the everted repeat are important regions for recognition by Uga3p. The studies with the truncated Uga3p (1 –124 a.a.), also suggested that the regions C-terminal to the DNA-binding motif and putative coiled-coil area of this protein are important for Uga3p-specific interactions with UAS[subscript GABA]. Investigation of regions C-terminal to the zinc cluster, linker and putative coiledcoil revealed an eight-motif regulatory region similar to that in other zinc cluster proteins. This indicated that the regions C-terminal to these domains are important for the regulation and activity of these proteins. A putative seven repeat WD40-like motif was identified within this region. This putative domain has been speculated to be important for protein-protein interactions. Phosphorylation and dephosphorylation in other proteins of this class have been indicated to be important for the regulation of the activity of these proteins. The bioinformatic analysis of Uga3p revealed two possible cAMP/cGMP-dependent protein kinase phosphorylation sites, four putative protein kinase C phosphorylation motifs and four putative casein kinase II phosphorylation motifs. This study has contributed to the understanding of the nature of interactions between Uga3p and its specific UAS [subscript GABA] and how the regions flanking the everted repeat determine its specificity. The comparison of the nature of the binding of truncated and full-length Uga3p in vitro provided evidence for the role played by the full-length protein in determining this specific interaction. This evidence suggested that the in vitro binding evidence for other proteins of this family, using truncated peptides that carry the DNA-binding domain, might not reflect the true nature of interactions between the proteins of this class and their specific UASs in vivo.
- Full Text:
- Date Issued: 2003