Mechanisms of luminescence in α-Al₂O₃:C : investigations using time-resolved optical stimulation and thermoluminescence techniques
- Authors: Nyirenda, Angel Newton
- Date: 2013
- Subjects: Thermoluminescence Aluminum oxide Optically stimulated luminescence dating Radiation dosimetry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5447 , http://hdl.handle.net/10962/d1002961
- Description: Carbon-doped aluminium oxide, α-Al₂O₃:C, is a ultra-sensitive dosimeter of topical research interest. The aim of this project was to investigate the dynamics of luminesce in this material. The methods of investigation consisted of thermoluminescence and time-resolved optical stimulation. Thermoluminescence measurements provide information on trap distribution and kinetic parameters of the traps involved in luminescence whereas time-resolved optical stimulation is a handy technique in investigation of luminescence lifetimes and provides an insight into the charge transitions between traps and recombination centres. Measurements were made on samples annealed at a nominal temperature of 900⁰C for 15 minutes. The material shows the presence of five thermoluminescence peaks at 37⁰C, 160⁰C, 300⁰C 410⁰C, and 480⁰C at a heating rate of 0.03k/s when irradiated to 6.0 Gy of beta. The main peak at 160⁰C, shows a linear dose response for doses between 0.1 Gy and 10 Gy and then goes sublinear above 10 Gy, the peak at 37⁰C shows a sublinear dose response for doses between 0.1 Gy and 10 Gy and appears to saturate thereafter, whereas the dose response of the peak at 300⁰C goes from linear to supralinear then apparently quadratic behaviour in the dose range of 0.1 Gy to 16.0 Gy. The trap depth of the main peak, that is, its activation energy as determined below the conduction band, has been approximated at 1.3 eV with a kinetic order of approximately 1.2. Time-resolved optical stimulation has been used to investigate luminescence lifetimes. The mean luminescence lifetime obtained for the sample at ambient temperatures is 35.0±1.0 ms. The investigations of the dependence of luminescence lifetimes on measurement temperature show that the material suffers from thermal quenching effects at measurement temperatures above 140⁰C with the activation energy of thermal quenching estimated at 1.045±0.002 eV. Shallow traps i.e. traps lying close to the conduction band, seem to elongate the lifetimes of optically stimulated luminescence in the material at temperatures between 30⁰C - 80⁰C due to charge retrapping. The material exhibits both fading and recuperation of the optically stimulated luminescence signal with storage time.
- Full Text:
- Date Issued: 2013
- Authors: Nyirenda, Angel Newton
- Date: 2013
- Subjects: Thermoluminescence Aluminum oxide Optically stimulated luminescence dating Radiation dosimetry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5447 , http://hdl.handle.net/10962/d1002961
- Description: Carbon-doped aluminium oxide, α-Al₂O₃:C, is a ultra-sensitive dosimeter of topical research interest. The aim of this project was to investigate the dynamics of luminesce in this material. The methods of investigation consisted of thermoluminescence and time-resolved optical stimulation. Thermoluminescence measurements provide information on trap distribution and kinetic parameters of the traps involved in luminescence whereas time-resolved optical stimulation is a handy technique in investigation of luminescence lifetimes and provides an insight into the charge transitions between traps and recombination centres. Measurements were made on samples annealed at a nominal temperature of 900⁰C for 15 minutes. The material shows the presence of five thermoluminescence peaks at 37⁰C, 160⁰C, 300⁰C 410⁰C, and 480⁰C at a heating rate of 0.03k/s when irradiated to 6.0 Gy of beta. The main peak at 160⁰C, shows a linear dose response for doses between 0.1 Gy and 10 Gy and then goes sublinear above 10 Gy, the peak at 37⁰C shows a sublinear dose response for doses between 0.1 Gy and 10 Gy and appears to saturate thereafter, whereas the dose response of the peak at 300⁰C goes from linear to supralinear then apparently quadratic behaviour in the dose range of 0.1 Gy to 16.0 Gy. The trap depth of the main peak, that is, its activation energy as determined below the conduction band, has been approximated at 1.3 eV with a kinetic order of approximately 1.2. Time-resolved optical stimulation has been used to investigate luminescence lifetimes. The mean luminescence lifetime obtained for the sample at ambient temperatures is 35.0±1.0 ms. The investigations of the dependence of luminescence lifetimes on measurement temperature show that the material suffers from thermal quenching effects at measurement temperatures above 140⁰C with the activation energy of thermal quenching estimated at 1.045±0.002 eV. Shallow traps i.e. traps lying close to the conduction band, seem to elongate the lifetimes of optically stimulated luminescence in the material at temperatures between 30⁰C - 80⁰C due to charge retrapping. The material exhibits both fading and recuperation of the optically stimulated luminescence signal with storage time.
- Full Text:
- Date Issued: 2013
Media ownership and transparency: regulation, ethics, accountability
- Authors: Rumney, Reg
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454229 , vital:75329 , https://hdl.handle.net/10520/EJC141591
- Description: It is hard to understand why such an intemperate war of words flared up over the change in ownership of one of South Africa's oldest and influential newspaper groups. Yet inquiries about the identity of the new owners of Independent News and Media South Africa (INMSA) generated a surprising ferocity from a surprising range of sources.
- Full Text:
- Date Issued: 2013
- Authors: Rumney, Reg
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454229 , vital:75329 , https://hdl.handle.net/10520/EJC141591
- Description: It is hard to understand why such an intemperate war of words flared up over the change in ownership of one of South Africa's oldest and influential newspaper groups. Yet inquiries about the identity of the new owners of Independent News and Media South Africa (INMSA) generated a surprising ferocity from a surprising range of sources.
- Full Text:
- Date Issued: 2013
Media, citizenship and the politics of belonging in contemporary South Africa:
- Milton, Viola C, Wasserman, Herman, Garman, Anthea
- Authors: Milton, Viola C , Wasserman, Herman , Garman, Anthea
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159802 , vital:40345 , DOI: 10.1080/02500167.2013.864447
- Description: Drawing on a wide range of theoretical and empirical studies, the articles in this special issue examine issues of citizenship and belonging in South Africa. Questions of belonging and citizenship are neither novel, nor particular to South Africa – they have been high on the intellectual (and popular) agenda internationally since at least the early 1990s. Yet South Africa's history of artificially separating and defining its citizens in the racial regimes of colonialism and apartheid still reverberates today, as is reflected in the continued inequalities marring South African society
- Full Text:
- Date Issued: 2013
- Authors: Milton, Viola C , Wasserman, Herman , Garman, Anthea
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159802 , vital:40345 , DOI: 10.1080/02500167.2013.864447
- Description: Drawing on a wide range of theoretical and empirical studies, the articles in this special issue examine issues of citizenship and belonging in South Africa. Questions of belonging and citizenship are neither novel, nor particular to South Africa – they have been high on the intellectual (and popular) agenda internationally since at least the early 1990s. Yet South Africa's history of artificially separating and defining its citizens in the racial regimes of colonialism and apartheid still reverberates today, as is reflected in the continued inequalities marring South African society
- Full Text:
- Date Issued: 2013
Mediation practice : perceptions of practitioners from the African insider mediators platform
- Authors: Smith, Richard
- Date: 2013
- Subjects: Mediation , Mediators (Persons) , Social conflict
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8353 , http://hdl.handle.net/10948/d1020909
- Description: In African countries emerging from periods of violent crisis a layer of civil society practitioners and peacebuilders appear to play a critical role in mediating the inevitable disputes and tensions that arise. This treatise focuses on a sample of these mediating practitioners who perceive themselves in a variety of different ways, as peacebuilders, as conflict managers, as conflict resolution practitioners and as conflict transformation practitioners. The practitioners who participated in this study work at multiple levels to support the mediative processes that are needed in contexts of crisis and transition. They form part of a wider group of practitioners who have taken the initiative to organise insider mediators into a learning community of practitioners, under the auspices of the African Insider Mediators Platform (AIMP). This platform provides scholars with a useful research opportunity. The overall aim of this study is to explore the relationship between conflict transformation theory and the establishment of the AIMP as perceived by AIMP practitioners. It captures the perceptions that mediators have of the nature of the conflicts in which they are engaged and the influence of theoretical approaches on their practice. The treatise focuses on the perceptions of selected mediation practitioners associated with the AIMP. It draws out the conceptual lenses that are used to inform perceptions of effective mediation practice and that connect the perceptions of practitioners with the concepts contained within the conflict transformation theory. In so doing it describes the perceptions of practitioners and discusses the extent to which these perceptions resonate or deviate from theoretical conceptualisations of conflict in Africa and the theoretical frameworks that outline what constitutes an effective mediative response to this conflict. The insights into effectiveness that emerge from this approach are outlined in the treatise, drawing from background research that has informed the formation of the AIMP as well as from interviews carried out with selected mediation practitioners. The research findings suggest that there are several perceived connections between the theoretical underpinnings of conflict transformation approaches and the practice of the insider mediators involved in this study. The discussion of the data puts forward the proposition that the conceptual perceptions of the insider mediators involved in the study, in their description of elements of mediation practice and the nature of conflict, resonate strongly with the theories associated with conflict transformation thinking. In addition several additional theoretical influences appear to have been incorporated into an overall approach to discrete and collaborative mediation efforts that reinforce a strong connection between conflict transformation thinking and the practice of insider mediators. These relational connections between theory and practice are outlined in some detail in the description of the study that follows.
- Full Text:
- Date Issued: 2013
- Authors: Smith, Richard
- Date: 2013
- Subjects: Mediation , Mediators (Persons) , Social conflict
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8353 , http://hdl.handle.net/10948/d1020909
- Description: In African countries emerging from periods of violent crisis a layer of civil society practitioners and peacebuilders appear to play a critical role in mediating the inevitable disputes and tensions that arise. This treatise focuses on a sample of these mediating practitioners who perceive themselves in a variety of different ways, as peacebuilders, as conflict managers, as conflict resolution practitioners and as conflict transformation practitioners. The practitioners who participated in this study work at multiple levels to support the mediative processes that are needed in contexts of crisis and transition. They form part of a wider group of practitioners who have taken the initiative to organise insider mediators into a learning community of practitioners, under the auspices of the African Insider Mediators Platform (AIMP). This platform provides scholars with a useful research opportunity. The overall aim of this study is to explore the relationship between conflict transformation theory and the establishment of the AIMP as perceived by AIMP practitioners. It captures the perceptions that mediators have of the nature of the conflicts in which they are engaged and the influence of theoretical approaches on their practice. The treatise focuses on the perceptions of selected mediation practitioners associated with the AIMP. It draws out the conceptual lenses that are used to inform perceptions of effective mediation practice and that connect the perceptions of practitioners with the concepts contained within the conflict transformation theory. In so doing it describes the perceptions of practitioners and discusses the extent to which these perceptions resonate or deviate from theoretical conceptualisations of conflict in Africa and the theoretical frameworks that outline what constitutes an effective mediative response to this conflict. The insights into effectiveness that emerge from this approach are outlined in the treatise, drawing from background research that has informed the formation of the AIMP as well as from interviews carried out with selected mediation practitioners. The research findings suggest that there are several perceived connections between the theoretical underpinnings of conflict transformation approaches and the practice of the insider mediators involved in this study. The discussion of the data puts forward the proposition that the conceptual perceptions of the insider mediators involved in the study, in their description of elements of mediation practice and the nature of conflict, resonate strongly with the theories associated with conflict transformation thinking. In addition several additional theoretical influences appear to have been incorporated into an overall approach to discrete and collaborative mediation efforts that reinforce a strong connection between conflict transformation thinking and the practice of insider mediators. These relational connections between theory and practice are outlined in some detail in the description of the study that follows.
- Full Text:
- Date Issued: 2013
Medical schemes fraud : ethical investigation of medical practitioners as stakeholders
- Authors: Titus, Phyllis May
- Date: 2013
- Subjects: Business ethics , Fraud investigation , Medicare fraud
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8895 , http://hdl.handle.net/10948/d1020899
- Description: A mere 16 percent of the population enjoys the benefits of private healthcare; medical schemes however remain an important contributor to the South African economy with an annual contribution flow of close to R85 billion per annum. Similar to the international scenario, South African healthcare inflation surpassed consumer price inflation. In addition, the medical schemes industry remains riddled with fraud, this coupled with escalating private healthcare costs remain subsequent threats to the sustainability of the industry. It is reported that service provider fraud has surpassed fraud committed by scheme members. Most medical schemes appear to have policies in place to manage and combat fraud, however transparency in terms of information sharing remains elusive. Of greater concern have been the investigation and management ethicality and endgame of medical schemes in terms of fraud risk management amongst medical practitioners. The research problem states that there is currently no standard fraud investigation and management protocol available for the ethical investigation and management of medical schemes fraud committed by medical practitioners. The literature review demonstrated that there has been a paradigm shift regarding the expectations that society has of the modern corporation and emphasised the inclusive stakeholder model theory in favour of the traditional shareholder dictum: pursuit of profit maximisation at any cost. The research design was done by providing a survey questionnaire to private medical practitioners. The literature review and survey findings highlighted the need for medical schemes to pay greater heed to their ethicality and stakeholder issue management practices. Focus areas for the development of an industry standard fraud investigation and management protocol was recommended.
- Full Text:
- Date Issued: 2013
- Authors: Titus, Phyllis May
- Date: 2013
- Subjects: Business ethics , Fraud investigation , Medicare fraud
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8895 , http://hdl.handle.net/10948/d1020899
- Description: A mere 16 percent of the population enjoys the benefits of private healthcare; medical schemes however remain an important contributor to the South African economy with an annual contribution flow of close to R85 billion per annum. Similar to the international scenario, South African healthcare inflation surpassed consumer price inflation. In addition, the medical schemes industry remains riddled with fraud, this coupled with escalating private healthcare costs remain subsequent threats to the sustainability of the industry. It is reported that service provider fraud has surpassed fraud committed by scheme members. Most medical schemes appear to have policies in place to manage and combat fraud, however transparency in terms of information sharing remains elusive. Of greater concern have been the investigation and management ethicality and endgame of medical schemes in terms of fraud risk management amongst medical practitioners. The research problem states that there is currently no standard fraud investigation and management protocol available for the ethical investigation and management of medical schemes fraud committed by medical practitioners. The literature review demonstrated that there has been a paradigm shift regarding the expectations that society has of the modern corporation and emphasised the inclusive stakeholder model theory in favour of the traditional shareholder dictum: pursuit of profit maximisation at any cost. The research design was done by providing a survey questionnaire to private medical practitioners. The literature review and survey findings highlighted the need for medical schemes to pay greater heed to their ethicality and stakeholder issue management practices. Focus areas for the development of an industry standard fraud investigation and management protocol was recommended.
- Full Text:
- Date Issued: 2013
Medicinal properties of some plants used for the treatment of skin disorders in the O. R. Tambo and Amathole Municipalities of the Eastern Cape Province, South Africa
- Authors: Mahachi, Josia
- Date: 2013
- Subjects: Medicinal plants -- Skin -- Diseases -- Treatment , South Africa -- Eastern Cape Province
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:18487 , http://hdl.handle.net/11260/101
- Description: The use of medicinal plants for treatment of skin infections and improvement of skin tone was assessed. The study covered Amathole and OR Tambo municipalities of the Eastern Cape Province of South Africa. The study sought to identify and document some medicinal plants which are used by the indigenous people on the skin, evaluate some biological properties which attribute to their use for therapeutic use. This report provides ethnobotanical data on some plant which were identified. Six medicinal plants (Kniphofia drepanophylla, Gnidia capitata, Hypoxis hemerocallidea, Syzgium cordatum, Macaranga capensis and Protorhus longifolia) which were implicated for treatment of skin diseases were screened for their antibacterial and antioxidant properties. Guided questionnaires were used to interview and gather ethnobotanical information from the traditional healers. Members of the communities which were indicated to be knowledgeable on use of medicinal plants in the areas were visited and interviewed. The results revealed that a total of 45 plant species distributed in 41 Genera belonging to 28 Families are used for treatment of skin infections and improvement of skin texture. The plant medicines were reported to be used as remedies against common skin problem such as wounds, pimples, acnes and itches. Some were reported to have anti-inflammatory effect on the skin while other were reported to oil dry skin and prevent skin dryness and dry eczematous conditions. Others like Cassipourea flanaganii, and Spirostachys africana were commonly used to enlighten skin and protect skin from ultra-violet radiation. The most common mode of preparation of these medicinal plants was pastes or decoctions. Sometimes crushed plant materials were put in bathing water or boiled and steamed on affected parts. It was reported that mixing pastes with oil, animal fat and milk improve medicinal properties. Water, methanol and acetone extracts of K. drepanophylla, G. capitata, H. hemerocallidea, S. cordatum, M. capensis and P. longifolia were screened against five strains of Gram negative bacteria. The results revealed that water extracts from five plant species inhibited two or more strains of bacteria with the most common minimum inhibitory concentrations (MICs) ranging between 5,0 to 10,0 mg/ml with the exception of aqueous extracts of K. drepanophylla which failed to inhibit all strains of bacteria. The screening of methanol extract of these plants for antioxidant and free radical activity revealed a significant activity with 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) free radical (DPPH). The extracts of P. longifolia, G. capitata, M. capensis, S. cordutum and H. hemerocallidea showed significantly higher free radical scavenging activity with IC50 of ranging from about 11.0 to 41.2 μg/ ml while the IC50 value for K. drepanophylla could not be determined at 100 μg/ ml. Generally the study showed that medicinal plants still play a very important role in the health care delivery system, especially in the O R Tambo and Amathole municipalities of the Eastern Cape. Botanical medicine remains pivotal in the treatment of skin ailments and improvement of the skin tone.
- Full Text:
- Date Issued: 2013
- Authors: Mahachi, Josia
- Date: 2013
- Subjects: Medicinal plants -- Skin -- Diseases -- Treatment , South Africa -- Eastern Cape Province
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:18487 , http://hdl.handle.net/11260/101
- Description: The use of medicinal plants for treatment of skin infections and improvement of skin tone was assessed. The study covered Amathole and OR Tambo municipalities of the Eastern Cape Province of South Africa. The study sought to identify and document some medicinal plants which are used by the indigenous people on the skin, evaluate some biological properties which attribute to their use for therapeutic use. This report provides ethnobotanical data on some plant which were identified. Six medicinal plants (Kniphofia drepanophylla, Gnidia capitata, Hypoxis hemerocallidea, Syzgium cordatum, Macaranga capensis and Protorhus longifolia) which were implicated for treatment of skin diseases were screened for their antibacterial and antioxidant properties. Guided questionnaires were used to interview and gather ethnobotanical information from the traditional healers. Members of the communities which were indicated to be knowledgeable on use of medicinal plants in the areas were visited and interviewed. The results revealed that a total of 45 plant species distributed in 41 Genera belonging to 28 Families are used for treatment of skin infections and improvement of skin texture. The plant medicines were reported to be used as remedies against common skin problem such as wounds, pimples, acnes and itches. Some were reported to have anti-inflammatory effect on the skin while other were reported to oil dry skin and prevent skin dryness and dry eczematous conditions. Others like Cassipourea flanaganii, and Spirostachys africana were commonly used to enlighten skin and protect skin from ultra-violet radiation. The most common mode of preparation of these medicinal plants was pastes or decoctions. Sometimes crushed plant materials were put in bathing water or boiled and steamed on affected parts. It was reported that mixing pastes with oil, animal fat and milk improve medicinal properties. Water, methanol and acetone extracts of K. drepanophylla, G. capitata, H. hemerocallidea, S. cordatum, M. capensis and P. longifolia were screened against five strains of Gram negative bacteria. The results revealed that water extracts from five plant species inhibited two or more strains of bacteria with the most common minimum inhibitory concentrations (MICs) ranging between 5,0 to 10,0 mg/ml with the exception of aqueous extracts of K. drepanophylla which failed to inhibit all strains of bacteria. The screening of methanol extract of these plants for antioxidant and free radical activity revealed a significant activity with 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) free radical (DPPH). The extracts of P. longifolia, G. capitata, M. capensis, S. cordutum and H. hemerocallidea showed significantly higher free radical scavenging activity with IC50 of ranging from about 11.0 to 41.2 μg/ ml while the IC50 value for K. drepanophylla could not be determined at 100 μg/ ml. Generally the study showed that medicinal plants still play a very important role in the health care delivery system, especially in the O R Tambo and Amathole municipalities of the Eastern Cape. Botanical medicine remains pivotal in the treatment of skin ailments and improvement of the skin tone.
- Full Text:
- Date Issued: 2013
Men and talk about legal abortion in South Africa : equality, support and rights discourses undermining reproductive ‘choice’
- Macleod, Catriona I, Hansjee, Jateen
- Authors: Macleod, Catriona I , Hansjee, Jateen
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6295 , http://hdl.handle.net/10962/d1014770 , http://www.tandfonline.com/doi/full/10.1080/13691058.2013.802815
- Description: Discursive constructions of abortion are embedded in the social and gendered power relations of a particular socio-historical space. As part of research on public discourses concerning abortion in South Africa where there has been a radical liberalisation of abortion legislation, we collected data from male group discussions about a vignette concerning abortion, and newspaper articles written by men about abortion. Our analysis revealed how discourses of equality, support and rights may be used by men to subtly undermine women's reproductive right to ‘choose’ an abortion. Within an Equal Partnership discourse, abortion, paired with the assumption of foetal personhood, was equated with violating an equal heterosexual partnership and a man's patriarchal duty to protect a child. A New Man discourse, which positions men as supportive of women, was paired with the assumption of men as rational and women as irrational in decision-making, to allow for the possibility of men dissuading women from terminating a pregnancy. A Rights discourse was invoked to suggest that abortion violates men's paternal rights.
- Full Text:
- Date Issued: 2013
- Authors: Macleod, Catriona I , Hansjee, Jateen
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6295 , http://hdl.handle.net/10962/d1014770 , http://www.tandfonline.com/doi/full/10.1080/13691058.2013.802815
- Description: Discursive constructions of abortion are embedded in the social and gendered power relations of a particular socio-historical space. As part of research on public discourses concerning abortion in South Africa where there has been a radical liberalisation of abortion legislation, we collected data from male group discussions about a vignette concerning abortion, and newspaper articles written by men about abortion. Our analysis revealed how discourses of equality, support and rights may be used by men to subtly undermine women's reproductive right to ‘choose’ an abortion. Within an Equal Partnership discourse, abortion, paired with the assumption of foetal personhood, was equated with violating an equal heterosexual partnership and a man's patriarchal duty to protect a child. A New Man discourse, which positions men as supportive of women, was paired with the assumption of men as rational and women as irrational in decision-making, to allow for the possibility of men dissuading women from terminating a pregnancy. A Rights discourse was invoked to suggest that abortion violates men's paternal rights.
- Full Text:
- Date Issued: 2013
Mentoring for best educational practice : a generic framework for whole school transformation within dysfunctional senior secondary schools, South Africa
- Authors: Mohamed, Gishma
- Date: 2013
- Subjects: Education -- Study and teaching -- South Africa , Low-performing schools -- South Africa , Social change -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9463 , http://hdl.handle.net/10948/d1020347
- Description: During transformation (1994 onwards), different interventions were instituted within Education as an attempt to redress learner achievement and throughput. By so doing, the South African government believed that by investing in education a return would be attained which would be beneficial to stabilising its economy — nationally and internationally. However, expected outcomes of these interventions have not been achieved and various researchers and opinion leaders still view the quality of education in South Africa as disparaging and deficient as well as characterised by an increasing prevalence of dysfunctional schooling systems. Therefore, this research aimed to design a generic mentoring framework through which transformation within dysfunctional schooling systems can be facilitated; this is to enable whole school development to achieve best educational practice. In order to achieve this, a micro-level analysis of schooling systems, using the functionalist perspective, specifically enabled through the contributions of Parsons and Merton was undertaken. In addition, insight gained from a broad range of literature and other secondary resources on mentoring, best practice and quality education was used to develop a number of premises. These premises were used to suggest how the generic mentoring framework can be adapted to enable a fit-for-purpose mentoring system which allows facilitation of a process of sustained transformation which gravitates towards a whole school culture that envisions quality education for all. It is recommended that further research be undertaken to ascertain the strength of the generic mentoring framework and operationalising it as a fit-for-purpose mentoring system within a school in the form of a pilot study. Aligned with this, to undertake assessment research, amongst other things, to systematically and with greater depth explore the notions of intended and unintended consequences that manifest during operationalisation of a fit-for-purpose mentoring system and how these can and should be measured.
- Full Text:
- Date Issued: 2013
- Authors: Mohamed, Gishma
- Date: 2013
- Subjects: Education -- Study and teaching -- South Africa , Low-performing schools -- South Africa , Social change -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9463 , http://hdl.handle.net/10948/d1020347
- Description: During transformation (1994 onwards), different interventions were instituted within Education as an attempt to redress learner achievement and throughput. By so doing, the South African government believed that by investing in education a return would be attained which would be beneficial to stabilising its economy — nationally and internationally. However, expected outcomes of these interventions have not been achieved and various researchers and opinion leaders still view the quality of education in South Africa as disparaging and deficient as well as characterised by an increasing prevalence of dysfunctional schooling systems. Therefore, this research aimed to design a generic mentoring framework through which transformation within dysfunctional schooling systems can be facilitated; this is to enable whole school development to achieve best educational practice. In order to achieve this, a micro-level analysis of schooling systems, using the functionalist perspective, specifically enabled through the contributions of Parsons and Merton was undertaken. In addition, insight gained from a broad range of literature and other secondary resources on mentoring, best practice and quality education was used to develop a number of premises. These premises were used to suggest how the generic mentoring framework can be adapted to enable a fit-for-purpose mentoring system which allows facilitation of a process of sustained transformation which gravitates towards a whole school culture that envisions quality education for all. It is recommended that further research be undertaken to ascertain the strength of the generic mentoring framework and operationalising it as a fit-for-purpose mentoring system within a school in the form of a pilot study. Aligned with this, to undertake assessment research, amongst other things, to systematically and with greater depth explore the notions of intended and unintended consequences that manifest during operationalisation of a fit-for-purpose mentoring system and how these can and should be measured.
- Full Text:
- Date Issued: 2013
Metal nanoparticles caused death of metastatic MDA-MB-231 breast cancer cells:
- Adeyemi, Oluyomi, Edkins, Adrienne L, Whiteley, Christopher
- Authors: Adeyemi, Oluyomi , Edkins, Adrienne L , Whiteley, Christopher
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164797 , vital:41173 , DOI: 10.1016/j.toxlet.2013.05.599
- Description: Available data on the toxicity of nanoparticles is a subject of controversy. The interaction of nanoparticles with biological systems including living cells has become one of the most urgent areas of collaborative research in materials science and biology. This is due to the fact that toxicity of nanomaterials are ill defined in terms of cause–effect relationships.
- Full Text:
- Date Issued: 2013
- Authors: Adeyemi, Oluyomi , Edkins, Adrienne L , Whiteley, Christopher
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164797 , vital:41173 , DOI: 10.1016/j.toxlet.2013.05.599
- Description: Available data on the toxicity of nanoparticles is a subject of controversy. The interaction of nanoparticles with biological systems including living cells has become one of the most urgent areas of collaborative research in materials science and biology. This is due to the fact that toxicity of nanomaterials are ill defined in terms of cause–effect relationships.
- Full Text:
- Date Issued: 2013
Mg/Triethylammonium Formate: A Useful System for Reductive Dimerization of Araldehydes into Pinacols;Nitroarenes into Azoarenes and Azoarenes into Hydrazoarenes
- Pamar, M Geeter, Govender, P, Muthusamy, K, Krause, Rui W M
- Authors: Pamar, M Geeter , Govender, P , Muthusamy, K , Krause, Rui W M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125107 , vital:35729 , https://doi.org/10.13005/ojc/290316
- Description: Studies are reported which describes the effectiveness of triethylammonium formate in the presence of magnesium for the efficient intermolecular pinacol coupling using MeOH as solvent. Various aromatic carbonyls underwent smooth reductive coupling to give the corresponding 1,2-diols. A series of azo compounds were obtained by the reductive coupling of nitroaromatics while azo compounds were reduced to the corresponding hydrazoarenes by this system. There was no adverse effect on the other reducible and hydrogenolysable groups such as ether linkage, hydroxy and halogens. The reactions are clean, high yielding and inexpensive. All the reactions proceeded smoothly at ambient temperature.
- Full Text:
- Date Issued: 2013
- Authors: Pamar, M Geeter , Govender, P , Muthusamy, K , Krause, Rui W M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125107 , vital:35729 , https://doi.org/10.13005/ojc/290316
- Description: Studies are reported which describes the effectiveness of triethylammonium formate in the presence of magnesium for the efficient intermolecular pinacol coupling using MeOH as solvent. Various aromatic carbonyls underwent smooth reductive coupling to give the corresponding 1,2-diols. A series of azo compounds were obtained by the reductive coupling of nitroaromatics while azo compounds were reduced to the corresponding hydrazoarenes by this system. There was no adverse effect on the other reducible and hydrogenolysable groups such as ether linkage, hydroxy and halogens. The reactions are clean, high yielding and inexpensive. All the reactions proceeded smoothly at ambient temperature.
- Full Text:
- Date Issued: 2013
Microbial agents for control of aquatic weeds and their role in integrated management
- Authors: Ray, P , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423550 , vital:72071 , xlink:href="https://www.cabidigitallibrary.org/doi/abs/10.1079/PAVSNNR20128014"
- Description: Aquatic ecosystems throughout the world are threatened by the presence of invasive aquatic plants, both floating and submerged. Some of the aquatic species, such as water hyacinth (Eichhornia crassipes [Mart.] Solms), alligator weed, Alternanthera philoxeroides (Mart.), giant salvinia, Salvinia molesta D.S. Mitchell and water lettuce (Pistia stratiotes L.), Griseb. despite being relatively minor problems in their native range, have become major invaders of aquatic habitats in other parts of the world after having escaped from their natural enemies. Unchecked growth of aquatic vegetation is generally undesirable and reduces the value of the water resource. Despite adopting all control options including manual, mechanical, chemical and classical biological, the problem persists. The current weed management is oriented towards finding approaches that are effective in controlling the weed and reducing environmental contamination from herbicides. Plant pathogens have been gaining increasing attention and interest among those concerned with developing environmentally friendly, effective and compatible approaches for integrated management of the noxious weeds. This paper discusses some of the major microbial agents associated with aquatic weeds and their increasing role in integrated weed management.
- Full Text:
- Date Issued: 2013
- Authors: Ray, P , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423550 , vital:72071 , xlink:href="https://www.cabidigitallibrary.org/doi/abs/10.1079/PAVSNNR20128014"
- Description: Aquatic ecosystems throughout the world are threatened by the presence of invasive aquatic plants, both floating and submerged. Some of the aquatic species, such as water hyacinth (Eichhornia crassipes [Mart.] Solms), alligator weed, Alternanthera philoxeroides (Mart.), giant salvinia, Salvinia molesta D.S. Mitchell and water lettuce (Pistia stratiotes L.), Griseb. despite being relatively minor problems in their native range, have become major invaders of aquatic habitats in other parts of the world after having escaped from their natural enemies. Unchecked growth of aquatic vegetation is generally undesirable and reduces the value of the water resource. Despite adopting all control options including manual, mechanical, chemical and classical biological, the problem persists. The current weed management is oriented towards finding approaches that are effective in controlling the weed and reducing environmental contamination from herbicides. Plant pathogens have been gaining increasing attention and interest among those concerned with developing environmentally friendly, effective and compatible approaches for integrated management of the noxious weeds. This paper discusses some of the major microbial agents associated with aquatic weeds and their increasing role in integrated weed management.
- Full Text:
- Date Issued: 2013
Microcystin enhances the fitness of microcystin producing cyanobacteria at high light intensities by either preventing or retarding photoinhibition
- Authors: Phelan, Richard Reginald
- Date: 2013
- Subjects: Microcystins , Microcystis , Cyanobacterial toxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10354 , http://hdl.handle.net/10948/d1020957
- Description: Several genera of cyanobacteria produce microcystin, a monocyclic peptide, with a unique chemical structure. To date, there have been over a 100 different structural variants of microcystin which have been identified. Microcystin production is affected by numerous environmental factors. However, the primary modulating factor for intracellular microcystin quota is the intracellular N:C ratio. No clearly defined biological role has been described for microcystin. Proposed roles for microcystin include defence against plankton grazers, metal chelation, an infochemical and a protectant against oxidative stress. There is sufficient evidence to support a biological role for microcystin in photosynthesis: microcystin is predominantly located in the thylakoid membranes, the microcystin gene cluster is differentially expressed as a function of light and a growth advantage for the microcystin producer in saturating light intensities. The purpose of this study is to investigate a possible biological role for microcystin in preventing photoinhibition and thus explaining the growth advantage observed in toxin-producers over non-toxin-producers. The uptake of exogenous microcystin was observed in Synechocystis PCC 6803 which was internalized and located in the thylakoid membranes and caused the inhibition of photosynthesis. Microcystin variants and increasing concentrations of microcystin-LR had no effect on the fluidity of the thylakoid membranes. The exposure of thylakoid membranes from Synechocystis PCC 6803 to physiologically relevant concentrations of different microcystin variants resulted in the inhibition of photosystem II activity but not photosystem I activity. The inhibition of photosystem II was variant dependent and concentration dependent for microcystin-LR and microcystin-RR. Chlorophyll a fluorescence data showed that photosystem II inhibition was caused by the inhibition of the oxygen evolving complex. Furthermore, a completion study revealed that the microcystin-producing Microcystis PCC 7806 had a competitive advantage over the non-microcystin producing ΔmcyA mutant of Microcystis PCC 7806 at high light intensities. The data indicates that microcystin protects the toxin-producer by either retarding or preventing photoinhibition and thus identifying the first data supported function for microcystin in cyanobacteria.
- Full Text:
- Date Issued: 2013
- Authors: Phelan, Richard Reginald
- Date: 2013
- Subjects: Microcystins , Microcystis , Cyanobacterial toxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10354 , http://hdl.handle.net/10948/d1020957
- Description: Several genera of cyanobacteria produce microcystin, a monocyclic peptide, with a unique chemical structure. To date, there have been over a 100 different structural variants of microcystin which have been identified. Microcystin production is affected by numerous environmental factors. However, the primary modulating factor for intracellular microcystin quota is the intracellular N:C ratio. No clearly defined biological role has been described for microcystin. Proposed roles for microcystin include defence against plankton grazers, metal chelation, an infochemical and a protectant against oxidative stress. There is sufficient evidence to support a biological role for microcystin in photosynthesis: microcystin is predominantly located in the thylakoid membranes, the microcystin gene cluster is differentially expressed as a function of light and a growth advantage for the microcystin producer in saturating light intensities. The purpose of this study is to investigate a possible biological role for microcystin in preventing photoinhibition and thus explaining the growth advantage observed in toxin-producers over non-toxin-producers. The uptake of exogenous microcystin was observed in Synechocystis PCC 6803 which was internalized and located in the thylakoid membranes and caused the inhibition of photosynthesis. Microcystin variants and increasing concentrations of microcystin-LR had no effect on the fluidity of the thylakoid membranes. The exposure of thylakoid membranes from Synechocystis PCC 6803 to physiologically relevant concentrations of different microcystin variants resulted in the inhibition of photosystem II activity but not photosystem I activity. The inhibition of photosystem II was variant dependent and concentration dependent for microcystin-LR and microcystin-RR. Chlorophyll a fluorescence data showed that photosystem II inhibition was caused by the inhibition of the oxygen evolving complex. Furthermore, a completion study revealed that the microcystin-producing Microcystis PCC 7806 had a competitive advantage over the non-microcystin producing ΔmcyA mutant of Microcystis PCC 7806 at high light intensities. The data indicates that microcystin protects the toxin-producer by either retarding or preventing photoinhibition and thus identifying the first data supported function for microcystin in cyanobacteria.
- Full Text:
- Date Issued: 2013
Microsatellite and morphometric analysis of chokka squid (Loligo reynaudi) from different spawning aggregations around the South African coast
- Authors: Stonier, Terence Anthony
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5344 , http://hdl.handle.net/10962/d1006779
- Description: Accurate information on stock structure is very important to the effective management of any commercially exploited species (Angel et al. 1994), particularly in annual species like Loligo reynaudi. Previous molecular work on a number of fish and cephalopod species has shown that stock structuring may be more complex than originally believed and while much scientific work has been conducted on Loligo reynaudi to date, molecular work has been lacking and this species’ fishery is currently managed as a single stock. The primary aim of this project was to examine the population genetics of Loligo reynaudi on a molecular level, by looking at the levels of genetic variation between different spawning aggregations along the inshore distribution of the chokka squid, with particular attention being paid to any variation between Eastern Cape and Agulhas Bank groups. The secondary aim was to conduct a morphological analysis on samples from the same major areas in order to see if any genetic variation observed would be complemented by phenotypic variation. Two separate sample sets were collected; Genetic samples were collected from 6 different spawning sites along the South African Coast between April and July, 2006 and whole individuals for morphometric analysis were collected from 4 spawning sites between April and July 2007. Samples were screened for genetic variation between different spawning aggregations along the inshore distribution of chokka squid, from Port Alfred in the Eastern Cape, to the western Agulhas Bank. After this a morphometric analysis on samples from the same major areas, Eastern Cape, Agulhas Bank and Angola, was carried out. Genetic results showed significant variation between some of the sample groups. As expected, the Angolan outgroup consistently showed significant variation from other samples, while there was evidence of differentiation between the South African samples themselves. These results could have implications for the previously documented life cycle model of Loligo reynaudi and provide a basis for further study at a finer resolution into where exactly the boundaries of these different groupings can be found. This stock structuring has implications for the management of the species and warrants further genetic research with microsatellites proving to be a powerful tool in the explanation of stock structuring. Unfortunately, due to possible errors in taking measurements, morphometric analysis did not yield useful results which can be described and interpreted in this study. It is felt that further genetic study conducted on a finer scale, should be accompanied by a repeat of the morphometric analysis.
- Full Text:
- Date Issued: 2013
- Authors: Stonier, Terence Anthony
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5344 , http://hdl.handle.net/10962/d1006779
- Description: Accurate information on stock structure is very important to the effective management of any commercially exploited species (Angel et al. 1994), particularly in annual species like Loligo reynaudi. Previous molecular work on a number of fish and cephalopod species has shown that stock structuring may be more complex than originally believed and while much scientific work has been conducted on Loligo reynaudi to date, molecular work has been lacking and this species’ fishery is currently managed as a single stock. The primary aim of this project was to examine the population genetics of Loligo reynaudi on a molecular level, by looking at the levels of genetic variation between different spawning aggregations along the inshore distribution of the chokka squid, with particular attention being paid to any variation between Eastern Cape and Agulhas Bank groups. The secondary aim was to conduct a morphological analysis on samples from the same major areas in order to see if any genetic variation observed would be complemented by phenotypic variation. Two separate sample sets were collected; Genetic samples were collected from 6 different spawning sites along the South African Coast between April and July, 2006 and whole individuals for morphometric analysis were collected from 4 spawning sites between April and July 2007. Samples were screened for genetic variation between different spawning aggregations along the inshore distribution of chokka squid, from Port Alfred in the Eastern Cape, to the western Agulhas Bank. After this a morphometric analysis on samples from the same major areas, Eastern Cape, Agulhas Bank and Angola, was carried out. Genetic results showed significant variation between some of the sample groups. As expected, the Angolan outgroup consistently showed significant variation from other samples, while there was evidence of differentiation between the South African samples themselves. These results could have implications for the previously documented life cycle model of Loligo reynaudi and provide a basis for further study at a finer resolution into where exactly the boundaries of these different groupings can be found. This stock structuring has implications for the management of the species and warrants further genetic research with microsatellites proving to be a powerful tool in the explanation of stock structuring. Unfortunately, due to possible errors in taking measurements, morphometric analysis did not yield useful results which can be described and interpreted in this study. It is felt that further genetic study conducted on a finer scale, should be accompanied by a repeat of the morphometric analysis.
- Full Text:
- Date Issued: 2013
Misconduct relating to fraud and corruption in the public service
- Authors: Madikane, Mpumelelo Patrick
- Date: 2013
- Subjects: Civil service -- South Africa , Civil service -- Corrupt practices
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10274 , http://hdl.handle.net/10948/d1018673
- Description: In an article, “Corruption and Governance Challenges: The South African Experience”,1 the Public Protector commented that corruption and good governance sit at the opposite ends of the spectrum. While good governance represents the ideal for governments, corporations and nations globally, corruption is a scourge that decent people, organisations and governments seek to eradicate. In the simplest of terms, corruption involves the abuse of power for private gain.The Public Protector further stated that it should be a concern to everybody that in post-independence Africa, certainly in South Africa, the accumulation of riches (in most cases, very sudden) is venerated even in the absence of visible means of accumulating the riches. South Africa has battled with corruption since the days of apartheid. Post-apartheid South Africa is a more open society and more opportunities have been created for detecting, exposing and prosecuting corruption. South Africa‟s approach to corruption is multipronged. The main pillars according to the Public Protector are the law, anti-corruption agencies, and public mobilisation.This studyhas attempted to attend to the challenges of managing misconduct relating to fraud and corruption that appear to weaken our democracy. Fraud and corruption is a complex phenomenon that requires managers and supervisors to possess a specialist technical knowledge in order to be effective in punishing those that are involved in this type of misconduct. The tendency currently is for the managers and supervisors to place suspected corrupt employees on a prolonged pre-cautionary suspension for a period that is not supported by law. This of course weakens the employer‟s case as they tend to rely on the outcomes of the proceedings in the criminal procedure before they institute disciplinary action against such culprits. Workers could be criminally prosecuted for this type of misconduct in terms of the provisions of the Prevention and Combating of the Corrupt Activities Act. Employers always enjoy the right to criminally prosecute workers who have committed acts of fraud or corruption but that must go concurrently with the institution of the disciplinary proceedings in terms of the collective agreement, if there is any. This study will show that the act of misconduct relating to fraud and corruption is a complex phenomenon that poses a threat to the global security. This study also takes a closer view of the provisions of international instruments and institutions such as the United Nations and International Labour Organisation. It further, does a detailed analysis of the provisions in other foreign jurisdiction like Canada. This is consistent with the provisions of the Bill of Rights as enshrined in the Constitution:Section 39(1) of the Constitution of the Republic of South Africa demands that when interpreting the Bill of Rights, a court, tribunal or forum: a. Must promote the values that underlie an open and democratic society based on human dignity, equality and freedom; b. Must consider international law; and c. May consider foreign law. Section 1 of the Labour Relations Act, states that the primary objects of the Act are: (a) To give effect and regulate the fundamental rights conferred by section 23 of the Constitution; (b) To give effect to obligations incurred by the Republic as a member state of the International Labour Organisation. Section 3 of the LRA further stipulates that any person applying this Act must interpret its provisions:(a) To give effect to its primary objects; (b) in compliance with the Constitution; (c) in compliance with the public international law obligations of the Republic.This treatise further shows the importance of the Constitutional values and principles that govern the Public Administration in terms of Chapter 10, section 195.Of importance the elements of fraud and corruption are discussed in this study.This study also gives a detailed analysis of the case laws that give guidance on how best to deal with and successfully punish employees involved in misconduct relating to fraud and corruption.
- Full Text:
- Date Issued: 2013
- Authors: Madikane, Mpumelelo Patrick
- Date: 2013
- Subjects: Civil service -- South Africa , Civil service -- Corrupt practices
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10274 , http://hdl.handle.net/10948/d1018673
- Description: In an article, “Corruption and Governance Challenges: The South African Experience”,1 the Public Protector commented that corruption and good governance sit at the opposite ends of the spectrum. While good governance represents the ideal for governments, corporations and nations globally, corruption is a scourge that decent people, organisations and governments seek to eradicate. In the simplest of terms, corruption involves the abuse of power for private gain.The Public Protector further stated that it should be a concern to everybody that in post-independence Africa, certainly in South Africa, the accumulation of riches (in most cases, very sudden) is venerated even in the absence of visible means of accumulating the riches. South Africa has battled with corruption since the days of apartheid. Post-apartheid South Africa is a more open society and more opportunities have been created for detecting, exposing and prosecuting corruption. South Africa‟s approach to corruption is multipronged. The main pillars according to the Public Protector are the law, anti-corruption agencies, and public mobilisation.This studyhas attempted to attend to the challenges of managing misconduct relating to fraud and corruption that appear to weaken our democracy. Fraud and corruption is a complex phenomenon that requires managers and supervisors to possess a specialist technical knowledge in order to be effective in punishing those that are involved in this type of misconduct. The tendency currently is for the managers and supervisors to place suspected corrupt employees on a prolonged pre-cautionary suspension for a period that is not supported by law. This of course weakens the employer‟s case as they tend to rely on the outcomes of the proceedings in the criminal procedure before they institute disciplinary action against such culprits. Workers could be criminally prosecuted for this type of misconduct in terms of the provisions of the Prevention and Combating of the Corrupt Activities Act. Employers always enjoy the right to criminally prosecute workers who have committed acts of fraud or corruption but that must go concurrently with the institution of the disciplinary proceedings in terms of the collective agreement, if there is any. This study will show that the act of misconduct relating to fraud and corruption is a complex phenomenon that poses a threat to the global security. This study also takes a closer view of the provisions of international instruments and institutions such as the United Nations and International Labour Organisation. It further, does a detailed analysis of the provisions in other foreign jurisdiction like Canada. This is consistent with the provisions of the Bill of Rights as enshrined in the Constitution:Section 39(1) of the Constitution of the Republic of South Africa demands that when interpreting the Bill of Rights, a court, tribunal or forum: a. Must promote the values that underlie an open and democratic society based on human dignity, equality and freedom; b. Must consider international law; and c. May consider foreign law. Section 1 of the Labour Relations Act, states that the primary objects of the Act are: (a) To give effect and regulate the fundamental rights conferred by section 23 of the Constitution; (b) To give effect to obligations incurred by the Republic as a member state of the International Labour Organisation. Section 3 of the LRA further stipulates that any person applying this Act must interpret its provisions:(a) To give effect to its primary objects; (b) in compliance with the Constitution; (c) in compliance with the public international law obligations of the Republic.This treatise further shows the importance of the Constitutional values and principles that govern the Public Administration in terms of Chapter 10, section 195.Of importance the elements of fraud and corruption are discussed in this study.This study also gives a detailed analysis of the case laws that give guidance on how best to deal with and successfully punish employees involved in misconduct relating to fraud and corruption.
- Full Text:
- Date Issued: 2013
Mobile technology moving past the gatekeepers: regulation, ethics, accountability
- Authors: Davis, Gavin
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454809 , vital:75378 , https://hdl.handle.net/10520/EJC141580
- Description: Opposition parties in Africa have struggled for decades in a media envi-ronment that favours incumbents. Of 54 African countries measured in the Freedom House 2012 Press Freedom Index, only five were consid-ered to be free. Press censorship and pliant public broadcasters mean that elections can be fixed before the first vote is even counted.
- Full Text:
- Date Issued: 2013
- Authors: Davis, Gavin
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454809 , vital:75378 , https://hdl.handle.net/10520/EJC141580
- Description: Opposition parties in Africa have struggled for decades in a media envi-ronment that favours incumbents. Of 54 African countries measured in the Freedom House 2012 Press Freedom Index, only five were consid-ered to be free. Press censorship and pliant public broadcasters mean that elections can be fixed before the first vote is even counted.
- Full Text:
- Date Issued: 2013
Modeling Complex Networked Audio Devices
- Eales, Andrew, Foss, Richard
- Authors: Eales, Andrew , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427012 , vital:72408 , https://www.aes.org/e-lib/browse.cfm?elib=16706
- Description: The lack of a universally accepted standard control protocol, as well as a lack of interoperability among existing protocols, limits how audio software can support a wide range of networked devices. To address this issue, the authors propose an abstract standard audio device model that is independent of any particular technology. This standard device model supports service discovery and enumeration, while also specifying device parts, the representation of parameter addresses, and the visual appearance of controls. The discussion explores the model in the context of a self-configuring discovery and control environment. Within this environment, controllers do not “pull” descriptions from a device; but rather, devices “push” full-service implementations to controllers.
- Full Text:
- Date Issued: 2013
- Authors: Eales, Andrew , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427012 , vital:72408 , https://www.aes.org/e-lib/browse.cfm?elib=16706
- Description: The lack of a universally accepted standard control protocol, as well as a lack of interoperability among existing protocols, limits how audio software can support a wide range of networked devices. To address this issue, the authors propose an abstract standard audio device model that is independent of any particular technology. This standard device model supports service discovery and enumeration, while also specifying device parts, the representation of parameter addresses, and the visual appearance of controls. The discussion explores the model in the context of a self-configuring discovery and control environment. Within this environment, controllers do not “pull” descriptions from a device; but rather, devices “push” full-service implementations to controllers.
- Full Text:
- Date Issued: 2013
Modelling of the performance of a batch biogas digester fed with selected types of substrates
- Authors: Mukumba, Patrick
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11596 , http://hdl.handle.net/10353/d1016197
- Description: The increasing population and the rapid economic growth in South Africa have led to higher consumption of food resulting in the generation of large amounts of waste. In addition, South Africa has plenty of biomass from cattle, donkeys, horses, goats, pigs, chicken and sheep. However, anaerobic digestion could be an alternative solution for the utilization of these kinds of waste due to its environmental and economic benefits. Therefore, the main focus of the research was design, construct a field batch biogas digester, monitor its performance when fed with co-substrates and model the methane yield for an optimized mixing ratio.
- Full Text:
- Date Issued: 2013
- Authors: Mukumba, Patrick
- Date: 2013
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11596 , http://hdl.handle.net/10353/d1016197
- Description: The increasing population and the rapid economic growth in South Africa have led to higher consumption of food resulting in the generation of large amounts of waste. In addition, South Africa has plenty of biomass from cattle, donkeys, horses, goats, pigs, chicken and sheep. However, anaerobic digestion could be an alternative solution for the utilization of these kinds of waste due to its environmental and economic benefits. Therefore, the main focus of the research was design, construct a field batch biogas digester, monitor its performance when fed with co-substrates and model the methane yield for an optimized mixing ratio.
- Full Text:
- Date Issued: 2013
Modelling stock return volatility dynamics in selected African markets
- Authors: King, Daniel Jonathan
- Date: 2013
- Subjects: Rate of return -- Africa Stocks -- Prices -- Africa Finance -- Developing countries -- Econometric models
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1051 , http://hdl.handle.net/10962/d1006452
- Description: Stock return volatility has been shown to occasionally exhibit discrete structural shifts. These shifts are particularly evident in the transition from ‘normal’ to crisis periods, and tend to be more pronounced in developing markets. This study aims to establish whether accounting for structural changes in the conditional variance process, through the use of Markov-switching models, improves estimates and forecasts of stock return volatility over those of the more conventional single-state (G)ARCH models, within and across selected African markets for the period 2002-2012. In the univariate portion of the study, the performances of various Markov-switching models are tested against a single-state benchmark model through the use of in-sample goodness-of-fit and predictive ability measures. In the multivariate context, the single-state and Markov-switching models are comparatively assessed according to their usefulness in constructing optimal stock portfolios. It is found that, even after accounting for structural breaks in the conditional variance process, conventional GARCH effects remain important to capturing the heteroscedasticity evident in the data. However, those univariate models which include a GARCH term are shown to perform comparatively poorly when used for forecasting purposes. Additionally, in the multivariate study, the use of Markov-switching variance-covariance estimates improves risk-adjusted portfolio returns when compared to portfolios that are constructed using the more conventional single-state models. While there is evidence that the use of some Markov-switching models can result in better forecasts and higher risk-adjusted returns than those models which include GARCH effects, the inability of the simpler Markov-switching models to fully capture the heteroscedasticity in the data remains problematic.
- Full Text:
- Date Issued: 2013
- Authors: King, Daniel Jonathan
- Date: 2013
- Subjects: Rate of return -- Africa Stocks -- Prices -- Africa Finance -- Developing countries -- Econometric models
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1051 , http://hdl.handle.net/10962/d1006452
- Description: Stock return volatility has been shown to occasionally exhibit discrete structural shifts. These shifts are particularly evident in the transition from ‘normal’ to crisis periods, and tend to be more pronounced in developing markets. This study aims to establish whether accounting for structural changes in the conditional variance process, through the use of Markov-switching models, improves estimates and forecasts of stock return volatility over those of the more conventional single-state (G)ARCH models, within and across selected African markets for the period 2002-2012. In the univariate portion of the study, the performances of various Markov-switching models are tested against a single-state benchmark model through the use of in-sample goodness-of-fit and predictive ability measures. In the multivariate context, the single-state and Markov-switching models are comparatively assessed according to their usefulness in constructing optimal stock portfolios. It is found that, even after accounting for structural breaks in the conditional variance process, conventional GARCH effects remain important to capturing the heteroscedasticity evident in the data. However, those univariate models which include a GARCH term are shown to perform comparatively poorly when used for forecasting purposes. Additionally, in the multivariate study, the use of Markov-switching variance-covariance estimates improves risk-adjusted portfolio returns when compared to portfolios that are constructed using the more conventional single-state models. While there is evidence that the use of some Markov-switching models can result in better forecasts and higher risk-adjusted returns than those models which include GARCH effects, the inability of the simpler Markov-switching models to fully capture the heteroscedasticity in the data remains problematic.
- Full Text:
- Date Issued: 2013
Modelling the impact of risk factors affecting TB treatment
- Authors: Tsuro, Urgent
- Date: 2013
- Subjects: Diseases -- Risk factors , Tuberculosis -- Epidemiology , Multidrug resistance
- Language: English
- Type: Thesis , Masters , MSc (Biostatistics and Epidemiology)
- Identifier: vital:11787 , http://hdl.handle.net/10353/d1019782 , Diseases -- Risk factors , Tuberculosis -- Epidemiology , Multidrug resistance
- Description: The Tuberculosis infection rate has been generally escalating due to poor health conditions in the Gweru district of Zimbabwe. The study therefore seeks to identify the risk factors that affect TB treatment in the Gweru district. A cross sectional study was carried out in which a questionnaire was employed for data collection on 113 respondents. A binary logistic regression model was employed for data analysis. A total of 98 TB patients were interviewed: [50 respondents (44.0%) had Multi-drug resistant Tuberculosis and 63 respondents (56.0%) had general Tuberculosis). Before being enrolled into the study, an informed consent form was given to each of the participants. The data was then put into excel and later transferred to SPSS for analysis. Out of the 14 potential risk factors of TB treatment, only 6 variables (side effects, gender, alcohol use, HIV status, smoking during the treatment period and having been pre-exposed to TB drugs) were statistically significant in their association with treatment failure.
- Full Text:
- Date Issued: 2013
- Authors: Tsuro, Urgent
- Date: 2013
- Subjects: Diseases -- Risk factors , Tuberculosis -- Epidemiology , Multidrug resistance
- Language: English
- Type: Thesis , Masters , MSc (Biostatistics and Epidemiology)
- Identifier: vital:11787 , http://hdl.handle.net/10353/d1019782 , Diseases -- Risk factors , Tuberculosis -- Epidemiology , Multidrug resistance
- Description: The Tuberculosis infection rate has been generally escalating due to poor health conditions in the Gweru district of Zimbabwe. The study therefore seeks to identify the risk factors that affect TB treatment in the Gweru district. A cross sectional study was carried out in which a questionnaire was employed for data collection on 113 respondents. A binary logistic regression model was employed for data analysis. A total of 98 TB patients were interviewed: [50 respondents (44.0%) had Multi-drug resistant Tuberculosis and 63 respondents (56.0%) had general Tuberculosis). Before being enrolled into the study, an informed consent form was given to each of the participants. The data was then put into excel and later transferred to SPSS for analysis. Out of the 14 potential risk factors of TB treatment, only 6 variables (side effects, gender, alcohol use, HIV status, smoking during the treatment period and having been pre-exposed to TB drugs) were statistically significant in their association with treatment failure.
- Full Text:
- Date Issued: 2013
Modulation of Plasmodium falciparum chaperones PfHsp70-1 and PfHsp70-x by small molecules
- Authors: Cockburn, Ingrid Louise
- Date: 2013
- Subjects: Plasmodium falciparum Heat shock proteins Molecular chaperones Homeostasis Protein folding Malaria Antimalarials Escherichia coli
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3887 , http://hdl.handle.net/10962/d1001747
- Description: The heat shock proteins of ~ 70 kDa (Hsp70s) are a conserved group of molecular chaperones important in maintaining the protein homeostasis in cells, carrying out functions including refolding of misfolded or unfolded proteins. Hsp70s function in conjunction with a number of other proteins including Hsp40 cochaperones. Central to the regulation Hsp70 activity is the Hsp70 ATPase cycle, involving ATP hydrolysis by Hsp70, and stimulation of this ATP hydrolysis by Hsp40. PfHsp70-1, the major cytosolic Hsp70 in the malaria parasite, Plasmodium falciparum, and PfHsp70-x, a novel malarial Hsp70 recently found to be exported to the host cell cytosol during the erythrocytic stages of the P. falciparum lifecycle, are both thought to play important roles in the malaria parasite’s survival and virulence, and thus represent novel antimalarial targets. Modulation of the function of these proteins by small molecules could thus lead to the development of antimalarials with novel targets and mechanisms. In the present study, malarial Hsp70s (PfHsp70-1 and PfHsp70-x), human Hsp70 (HSPA1A), malarial Hsp40 (PfHsp40) and human Hsp40 (Hsj1a) were recombinantly produced in Escherichia coli. In a characterisation of the chaperone activity of recombinant PfHsp70-x, the protein was found to have a basal ATPase activity (15.7 nmol ATP/min/mg protein) comparable to that previously described for PfHsp70-1, and an aggregation suppression activity significantly higher than that of PfHsp70-1. In vitro assays were used to screen five compounds of interest (lapachol, bromo-β-lapachona and malonganenones A, B and C) belonging to two compound classes (1,4 naphthoquinones and prenylated alkaloids) for modulatory effects on PfHsp70-1, PfHsp70-x and HsHsp70. A wide range of effects by compounds on the chaperone activities of Hsp70s was observed, including differential effects by compounds on different Hsp70s despite high conservation (≥ 70 % sequence identity) between the Hsp70s. The five compounds were shown to interact with all three Hsp70s in in vitro binding studies. Differential modulation by compounds was observed between the Hsj1a-stimulated ATPase activities of different Hsp70s, suggestive of not only a high degree of specificity of compounds to chaperone systems, but also distinct interactions between different Hsp70s and Hjs1a. The effects of compounds on the survival of P. falciparum parasites as well as mammalian cells was assessed. Bromo-β-lapachona was found to have broad effects across all systems, modulating the chaperone activities of all three Hsp70s, and showing significant toxicity toward both P. falciparum parasites and mammalian cells in culture. Malonganenone A was found to modulate only the malarial Hsp70s, not human Hsp70, showing significant toxicity toward malarial parasites (IC₅₀ ~ 0.8 μM), and comparatively low toxicity toward mammalian cells, representing therefore a novel starting point for a new class of antimalarials potentially targeting a new antimalarial drug target, Hsp70.
- Full Text:
- Date Issued: 2013
- Authors: Cockburn, Ingrid Louise
- Date: 2013
- Subjects: Plasmodium falciparum Heat shock proteins Molecular chaperones Homeostasis Protein folding Malaria Antimalarials Escherichia coli
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3887 , http://hdl.handle.net/10962/d1001747
- Description: The heat shock proteins of ~ 70 kDa (Hsp70s) are a conserved group of molecular chaperones important in maintaining the protein homeostasis in cells, carrying out functions including refolding of misfolded or unfolded proteins. Hsp70s function in conjunction with a number of other proteins including Hsp40 cochaperones. Central to the regulation Hsp70 activity is the Hsp70 ATPase cycle, involving ATP hydrolysis by Hsp70, and stimulation of this ATP hydrolysis by Hsp40. PfHsp70-1, the major cytosolic Hsp70 in the malaria parasite, Plasmodium falciparum, and PfHsp70-x, a novel malarial Hsp70 recently found to be exported to the host cell cytosol during the erythrocytic stages of the P. falciparum lifecycle, are both thought to play important roles in the malaria parasite’s survival and virulence, and thus represent novel antimalarial targets. Modulation of the function of these proteins by small molecules could thus lead to the development of antimalarials with novel targets and mechanisms. In the present study, malarial Hsp70s (PfHsp70-1 and PfHsp70-x), human Hsp70 (HSPA1A), malarial Hsp40 (PfHsp40) and human Hsp40 (Hsj1a) were recombinantly produced in Escherichia coli. In a characterisation of the chaperone activity of recombinant PfHsp70-x, the protein was found to have a basal ATPase activity (15.7 nmol ATP/min/mg protein) comparable to that previously described for PfHsp70-1, and an aggregation suppression activity significantly higher than that of PfHsp70-1. In vitro assays were used to screen five compounds of interest (lapachol, bromo-β-lapachona and malonganenones A, B and C) belonging to two compound classes (1,4 naphthoquinones and prenylated alkaloids) for modulatory effects on PfHsp70-1, PfHsp70-x and HsHsp70. A wide range of effects by compounds on the chaperone activities of Hsp70s was observed, including differential effects by compounds on different Hsp70s despite high conservation (≥ 70 % sequence identity) between the Hsp70s. The five compounds were shown to interact with all three Hsp70s in in vitro binding studies. Differential modulation by compounds was observed between the Hsj1a-stimulated ATPase activities of different Hsp70s, suggestive of not only a high degree of specificity of compounds to chaperone systems, but also distinct interactions between different Hsp70s and Hjs1a. The effects of compounds on the survival of P. falciparum parasites as well as mammalian cells was assessed. Bromo-β-lapachona was found to have broad effects across all systems, modulating the chaperone activities of all three Hsp70s, and showing significant toxicity toward both P. falciparum parasites and mammalian cells in culture. Malonganenone A was found to modulate only the malarial Hsp70s, not human Hsp70, showing significant toxicity toward malarial parasites (IC₅₀ ~ 0.8 μM), and comparatively low toxicity toward mammalian cells, representing therefore a novel starting point for a new class of antimalarials potentially targeting a new antimalarial drug target, Hsp70.
- Full Text:
- Date Issued: 2013