Factors that shape learner achievement in socially disadvantaged and rural contexts: a social realist study in two rural senior secondary schools in Omusati region, Namibia
- Authors: Shilongo, Erica
- Date: 2018
- Subjects: Academic achievement Namibia Omusati , High school students Namibia Omusati Social conditions , Rural schools Namibia Omusati , Education, Rural Namibia Omusati , Social realism
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62240 , vital:28146
- Description: Learners’ performance and the reasons for either achievement or failure in school has lo ng been a topic of debate. In early research on academic achievement, theorists, educators, biologists and psychologists traditionally focused on the learners from socially disadvantaged family backgrounds who underachieve. Much of the debate internationally centred on whether learner academic achievement / underachievement is a product of hereditary traits or the social context. In particular, arguments for and against whether the reasons for the achievement / underachievement of children from socially disadvantaged families are genetic or the social context in which they find themselves continue unabated. Such explanations do not provide insight into why it is that despite familial (genetic) and social circumstances (social disadvantage), some children succeed and/or are able to act outside expectations of failure. Little research has focused on those in the same or similar contexts who are achieving academic success despite their limiting circumstances and the reasons for their success. This study used a social realist lens to investigate the factors that shape the academic achievement of 12 learners in two rural senior secondary schools in Omusati region, Namibia. All 12 learners are from low socioeconomic family backgrounds. The data was collected through survey, interviews with learners, parents and teachers, field notes and document analysis. The main finding of the study show that contrary to research that portrayed learners’ achievement as determined either by heredity or social contexts, the 12 learners constantly used their agentic possibilities to navigate constraining structural and cultural conditions at regional, familial and school levels to achieve academic success. Their agency was shaped by the socioeconomic conditions in their lives, namely, socioeconomic deprivation; large extended families in rural households, lack of amenities and utilities in their families, participation in household chores, experience of family tragedies and of changes when they were young.
- Full Text:
- Date Issued: 2018
- Authors: Shilongo, Erica
- Date: 2018
- Subjects: Academic achievement Namibia Omusati , High school students Namibia Omusati Social conditions , Rural schools Namibia Omusati , Education, Rural Namibia Omusati , Social realism
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62240 , vital:28146
- Description: Learners’ performance and the reasons for either achievement or failure in school has lo ng been a topic of debate. In early research on academic achievement, theorists, educators, biologists and psychologists traditionally focused on the learners from socially disadvantaged family backgrounds who underachieve. Much of the debate internationally centred on whether learner academic achievement / underachievement is a product of hereditary traits or the social context. In particular, arguments for and against whether the reasons for the achievement / underachievement of children from socially disadvantaged families are genetic or the social context in which they find themselves continue unabated. Such explanations do not provide insight into why it is that despite familial (genetic) and social circumstances (social disadvantage), some children succeed and/or are able to act outside expectations of failure. Little research has focused on those in the same or similar contexts who are achieving academic success despite their limiting circumstances and the reasons for their success. This study used a social realist lens to investigate the factors that shape the academic achievement of 12 learners in two rural senior secondary schools in Omusati region, Namibia. All 12 learners are from low socioeconomic family backgrounds. The data was collected through survey, interviews with learners, parents and teachers, field notes and document analysis. The main finding of the study show that contrary to research that portrayed learners’ achievement as determined either by heredity or social contexts, the 12 learners constantly used their agentic possibilities to navigate constraining structural and cultural conditions at regional, familial and school levels to achieve academic success. Their agency was shaped by the socioeconomic conditions in their lives, namely, socioeconomic deprivation; large extended families in rural households, lack of amenities and utilities in their families, participation in household chores, experience of family tragedies and of changes when they were young.
- Full Text:
- Date Issued: 2018
Biotic and abiotic factors promoting the development and proliferation of water hyacinth (eichhornia crassipes (Mart.) Solms-Laub.) in the Wouri Basin (Douala-Cameroon) and environs, with implications for its control
- Voukeng, Sonia Nadege Kenfack
- Authors: Voukeng, Sonia Nadege Kenfack
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7644 , vital:21281
- Description: The Wouri River, situated in the Wouri Basin, is one of the main rivers of the Littoral Region in the city of Douala in Cameroon. It is a source of income and food for the population living around these areas. Since the 1990s, the fishing, transportation, irrigation and sand extraction activities have been impeded by the invasion of aquatic plants, specifically water hyacinth (Eichhornia crassipes [Mart.] Solms-Laubach: Pontederiaceae). Introduced in 1997 to the shore of Lake Chad, water hyacinth has invaded almost 114 ha of the Wouri Basin. Furthermore, Douala, the economic capital of the Cameroon and location for more than 70% of the country’s industries, uses the Wouri River and its tributaries to deposit its effluent and waste, which has worsened the problem of water hyacinth. This thesis examined the ecological and socio-economic impacts of water hyacinth in the Wouri Basin and its possible control. An increase in the nutrients in the water has provided water hyacinth with appropriate conditions for its fast growth during both the rainy and dry seasons. The availability of nutrients in these areas is enhanced by the constant, daily tidal fluctuation of water, providing enough water to the plant for easy nutrient uptake. A survey of the impacts of water hyacinth on aquatic plant communities in the Wouri Basin showed that this plant is able to out-compete native species. Assessment of the impact of water hyacinth on the abundance and diversity of plant communities indicated that at some invaded sites, 65% of the vegetation consisted of water hyacinth. Species found in association with water hyacinth with a high level of abundance-dominance were Pistia stratiotes L. (Araceae) (another invader), Commelina benghalensis L. (Commelinaceae) and Echinochloa pyramidalis (Lam.) Hitchc. & Chase (Poaceae). This component of the study also showed that habitats rich in water hyacinth were poor in diversity, while habitats without water hyacinth were rich in diversity, thus raising awareness of the importance of monitoring invasive aquatic weeds along the Wouri Basin, and of implementing correct control management of all invasive aquatic weeds. Communities living along the invaded rivers are well aware of the range of problems caused by the weed; because as the rivers and water bodies used for fishing, transportation, and sand extraction are progressively invaded by the weed, the riparian population is the first to feel the impact. The impact on people has been noticeable, with an increase in diseases, such as malaria, cholera, diarrhoea, typhoid, filariasis, schistosomiasis, scabies and yellow fever increasing the need for a medicine and hospitalization. Economic losses due to the management of invasive aquatic weeds were recorded, and the Ministry of Environment spent an estimated US$1 200 000 between 2010 and 2015 to manage this scourge. In 2016, an amount of US$160 000 was transferred to these regions to manage invasive aquatic weeds, especially water hyacinth, although manual clearing is still the only method used to control this weed. Isolation of fungi from diseased water hyacinth plants in the Wouri Basin revealed several fungal species, most of which have been isolated from water hyacinth species in water bodies elsewhere, which showed a higher diversity during the dry season than during the rainy season. These fungi included Acremonium zonatum (Sawada). W. Gams (Hypocreaceae), Alternaria eichhorniae Nag Raj & Ponnappa (Pleosporaceae), Chaetomium sp., Colletotrichum sp., Curvularia pallescens Boedjin (Pleosporaceae), Curvalaria sp., Epicoccum nigrum Link (Pleosporaceae), Fusarium sp., Pithomyces chartarum fBerk. & M. A. Curtis) M. B. Ellis (Montagnulaceae), to a lesser extent Myrothecium roridum Tode ex Fr. (Incertae sedis) and Nigrospora sp. Although never released in Cameroon, arthropod biological control agents (Neochetina eichhorniae Warner (Coleoptera, Curculionidae) and N. bruchi Hustache (Coleoptera, Curculionidae)) were present, but their populations were relatively low. The slow spread of the insect population was explained by several factors, among them the tidal fluctuation of water, which has an impact on the population growth of the weevils. Whilst adults may be able to survive tidal fluctuations, larvae are severely impacted by them, contributing to the slow success of biological control. In this study, a significant increase in pathogen-induced disease severity and incidence was noted when Neochetina eichhorniae weevils were present, possibly because larvae tunnelling on the petiole created openings for the penetration of fungal spores. This study highlights the negative impacts of water hyacinth, on the environment, people, and thus economy of Cameroon. The presence of biological control agents and pathogens offers Cameroon the possibility of initiating and properly implementing the biological control option, or an integrated management solution, to manage water hyacinth in the Wouri Basin, and in the rest of Cameroon.
- Full Text:
- Date Issued: 2017
- Authors: Voukeng, Sonia Nadege Kenfack
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7644 , vital:21281
- Description: The Wouri River, situated in the Wouri Basin, is one of the main rivers of the Littoral Region in the city of Douala in Cameroon. It is a source of income and food for the population living around these areas. Since the 1990s, the fishing, transportation, irrigation and sand extraction activities have been impeded by the invasion of aquatic plants, specifically water hyacinth (Eichhornia crassipes [Mart.] Solms-Laubach: Pontederiaceae). Introduced in 1997 to the shore of Lake Chad, water hyacinth has invaded almost 114 ha of the Wouri Basin. Furthermore, Douala, the economic capital of the Cameroon and location for more than 70% of the country’s industries, uses the Wouri River and its tributaries to deposit its effluent and waste, which has worsened the problem of water hyacinth. This thesis examined the ecological and socio-economic impacts of water hyacinth in the Wouri Basin and its possible control. An increase in the nutrients in the water has provided water hyacinth with appropriate conditions for its fast growth during both the rainy and dry seasons. The availability of nutrients in these areas is enhanced by the constant, daily tidal fluctuation of water, providing enough water to the plant for easy nutrient uptake. A survey of the impacts of water hyacinth on aquatic plant communities in the Wouri Basin showed that this plant is able to out-compete native species. Assessment of the impact of water hyacinth on the abundance and diversity of plant communities indicated that at some invaded sites, 65% of the vegetation consisted of water hyacinth. Species found in association with water hyacinth with a high level of abundance-dominance were Pistia stratiotes L. (Araceae) (another invader), Commelina benghalensis L. (Commelinaceae) and Echinochloa pyramidalis (Lam.) Hitchc. & Chase (Poaceae). This component of the study also showed that habitats rich in water hyacinth were poor in diversity, while habitats without water hyacinth were rich in diversity, thus raising awareness of the importance of monitoring invasive aquatic weeds along the Wouri Basin, and of implementing correct control management of all invasive aquatic weeds. Communities living along the invaded rivers are well aware of the range of problems caused by the weed; because as the rivers and water bodies used for fishing, transportation, and sand extraction are progressively invaded by the weed, the riparian population is the first to feel the impact. The impact on people has been noticeable, with an increase in diseases, such as malaria, cholera, diarrhoea, typhoid, filariasis, schistosomiasis, scabies and yellow fever increasing the need for a medicine and hospitalization. Economic losses due to the management of invasive aquatic weeds were recorded, and the Ministry of Environment spent an estimated US$1 200 000 between 2010 and 2015 to manage this scourge. In 2016, an amount of US$160 000 was transferred to these regions to manage invasive aquatic weeds, especially water hyacinth, although manual clearing is still the only method used to control this weed. Isolation of fungi from diseased water hyacinth plants in the Wouri Basin revealed several fungal species, most of which have been isolated from water hyacinth species in water bodies elsewhere, which showed a higher diversity during the dry season than during the rainy season. These fungi included Acremonium zonatum (Sawada). W. Gams (Hypocreaceae), Alternaria eichhorniae Nag Raj & Ponnappa (Pleosporaceae), Chaetomium sp., Colletotrichum sp., Curvularia pallescens Boedjin (Pleosporaceae), Curvalaria sp., Epicoccum nigrum Link (Pleosporaceae), Fusarium sp., Pithomyces chartarum fBerk. & M. A. Curtis) M. B. Ellis (Montagnulaceae), to a lesser extent Myrothecium roridum Tode ex Fr. (Incertae sedis) and Nigrospora sp. Although never released in Cameroon, arthropod biological control agents (Neochetina eichhorniae Warner (Coleoptera, Curculionidae) and N. bruchi Hustache (Coleoptera, Curculionidae)) were present, but their populations were relatively low. The slow spread of the insect population was explained by several factors, among them the tidal fluctuation of water, which has an impact on the population growth of the weevils. Whilst adults may be able to survive tidal fluctuations, larvae are severely impacted by them, contributing to the slow success of biological control. In this study, a significant increase in pathogen-induced disease severity and incidence was noted when Neochetina eichhorniae weevils were present, possibly because larvae tunnelling on the petiole created openings for the penetration of fungal spores. This study highlights the negative impacts of water hyacinth, on the environment, people, and thus economy of Cameroon. The presence of biological control agents and pathogens offers Cameroon the possibility of initiating and properly implementing the biological control option, or an integrated management solution, to manage water hyacinth in the Wouri Basin, and in the rest of Cameroon.
- Full Text:
- Date Issued: 2017
Photophysical and photochemical studies of non-transition metal phthalocyanine derivatives
- Ogunsipe, Abimbola Olukayode
- Authors: Ogunsipe, Abimbola Olukayode
- Date: 2005
- Subjects: Photochemotherapy Phthalocyanines Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4445 , http://hdl.handle.net/10962/d1007721
- Description: A detailed photophysicochemical study of some non-transition metal (AI, Zn, Si, Ge, and Sn) metallophthalocyanine (MPc) derivatives is presented. The effects of substituents, central metal ions and solvents on the photophysical and photochemical properties are investigated and rationalized accordingly. The presence of peripheral substituents on the macrocycle enhances the yield of the triplet state. Near infra-red absorptions of the solvents reveal that solvents which absorb around 1100 nm and around 1270 nm, quench the triplet state of the MPc derivative and singlet oxygen, respectively. Although water has a high singlet oxygen quenching effect, the singlet oxygen quantum yield (Φ∆) value for sulphonated zinc phthalocyanine in water is still reasonably high at 0.48, which may provide an explanation for the efficient photosensitization by this molecule in photodynamic studies. The lowering of Φ∆ following protonation of the MPc macrocycle is attributed to the lowering of triplet energy to the level where energy transfer to ground state oxygen is no longer favourable. MPc inclusion complexes with cyclodextrins showed larger Φ∆ values when compared to the complexes before inclusion. Job's plots show that 2:1 and 4:1 (CD:MPc) complexes may be formed. Fluorescence quenching by electron donors and acceptors were analysed by StemVolmer relationship and the results used in determining fluorescence lifetimes of the complexes. Qualitative and quantitative interpretations of the interaction of sulphonated MPcs with bovine serum albumin (BSA) are provided in this thesis. 1:1 adducts were formed with BSA, but the binding feasibilities varied markedly. Spectral, photophysical and photochemical properties of the complexes are altered in the presence of BSA.
- Full Text:
- Date Issued: 2005
- Authors: Ogunsipe, Abimbola Olukayode
- Date: 2005
- Subjects: Photochemotherapy Phthalocyanines Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4445 , http://hdl.handle.net/10962/d1007721
- Description: A detailed photophysicochemical study of some non-transition metal (AI, Zn, Si, Ge, and Sn) metallophthalocyanine (MPc) derivatives is presented. The effects of substituents, central metal ions and solvents on the photophysical and photochemical properties are investigated and rationalized accordingly. The presence of peripheral substituents on the macrocycle enhances the yield of the triplet state. Near infra-red absorptions of the solvents reveal that solvents which absorb around 1100 nm and around 1270 nm, quench the triplet state of the MPc derivative and singlet oxygen, respectively. Although water has a high singlet oxygen quenching effect, the singlet oxygen quantum yield (Φ∆) value for sulphonated zinc phthalocyanine in water is still reasonably high at 0.48, which may provide an explanation for the efficient photosensitization by this molecule in photodynamic studies. The lowering of Φ∆ following protonation of the MPc macrocycle is attributed to the lowering of triplet energy to the level where energy transfer to ground state oxygen is no longer favourable. MPc inclusion complexes with cyclodextrins showed larger Φ∆ values when compared to the complexes before inclusion. Job's plots show that 2:1 and 4:1 (CD:MPc) complexes may be formed. Fluorescence quenching by electron donors and acceptors were analysed by StemVolmer relationship and the results used in determining fluorescence lifetimes of the complexes. Qualitative and quantitative interpretations of the interaction of sulphonated MPcs with bovine serum albumin (BSA) are provided in this thesis. 1:1 adducts were formed with BSA, but the binding feasibilities varied markedly. Spectral, photophysical and photochemical properties of the complexes are altered in the presence of BSA.
- Full Text:
- Date Issued: 2005
The fishes of Tristan Da Cunha and Gough Island (South Atlantic), and the effects of environmental seasonality on the biology of selected species
- Authors: Andrew, Timothy Gilbert
- Date: 1993
- Subjects: Fishes -- Tristan da Cunha Fishes -- Gough Island Fishes -- Conservation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5284 , http://hdl.handle.net/10962/d1005128
- Description: This study focuses on the taxonomy, biogeography and biological aspects of the fishes of Tristan da Cunha and Gough Island in the cental South Atlantic Ocean. Oceanographic measurements were undertaken to determine the position and nature of the Subtropical Convergence (STC) in the vicinity of the islands. The Tristan da Cunha group is thought to be situated on the northern edge of the STC while Gough Island is situated on the southern edge of the front. The seasonal environmental cycle at the islands is characterised by an annual sea surface temperature fluctuation of approximately 5 °C and an annual change in stratification of the water column. It is suggested that this increase in stratification at the STC, brought about in the summer by insolation warming the surface layers of the ocean, enhances primary production. The STC is identified as a unique habitat for fishes and as an important barrier to dispersal of species in the Southern Ocean. The present study has produced 18 new distributional records from the shelf waters of Tristan da Cunha and Gough Island. The fish fauna known from the shelf waters of these islands is reviewed, and a diagnosis, synonymy, and in some cases an illustration are provided. For certain species, brief notes on their biology, relative abundance and seasonal distribution are included. An analysis of the ichthyofaunal relationships between shallow water areas in the vicinity of the STC has resulted in the identification of a characteristic neritic STC ichthyofauna. The circumglobal distribution of many of these species is thought to be a consequence of a dispersive pelagic phase in their life-cycles. Biological processes in fishes at these islands are temporally and spatially affected by seasonal changes in oceanographic conditions. Seasonal sea temperature variation was identified as being an indicator of other oceanographic phenomena that may affect processes such as growth, reproduction and feeding in fishes at the islands. Most species have a summer spawning season and growth rate increased during the summer months. It was hypothesised that enhanced primary production and a related increase in food quality and availability during the summer were the major factors temporally regulating the growth and reproduction of fishes at the islands. Twenty families of neritic fishes have been recorded in the shelf waters of Tristan da Cunhaand Gough Island. Most families are represented by only one species. Because of this a wide range of life-history strategies are apparent in the fauna. Nevertheless, there are a number of common life-history characteristics shared by most of the neritic species. Firstly, the early lifehistory of many species included an extended pelagic phase which might have facilitated colonisation throughout the STC zone in the past, thereby regulating extant species diversity in this region. Secondly, the common occurrence of an extended summer breeding season and iteroparity suggested that these characters also contributed to survival in what is considered to be an unpredictable environment. It would appear that these common characteristics hold the key to the success of many fishes in the STC zone. This study has contributed to our understanding of oceanic island ecosystems and has revealed distributional patterns of fishes that were unknown previously. By focusing on the biological processes of selected species the regulatory role played by local environmental conditions became apparent. The results of this study are also relevant to proposed conservation measures for Tristan da Cunha and Gough Island.
- Full Text:
- Date Issued: 1993
- Authors: Andrew, Timothy Gilbert
- Date: 1993
- Subjects: Fishes -- Tristan da Cunha Fishes -- Gough Island Fishes -- Conservation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5284 , http://hdl.handle.net/10962/d1005128
- Description: This study focuses on the taxonomy, biogeography and biological aspects of the fishes of Tristan da Cunha and Gough Island in the cental South Atlantic Ocean. Oceanographic measurements were undertaken to determine the position and nature of the Subtropical Convergence (STC) in the vicinity of the islands. The Tristan da Cunha group is thought to be situated on the northern edge of the STC while Gough Island is situated on the southern edge of the front. The seasonal environmental cycle at the islands is characterised by an annual sea surface temperature fluctuation of approximately 5 °C and an annual change in stratification of the water column. It is suggested that this increase in stratification at the STC, brought about in the summer by insolation warming the surface layers of the ocean, enhances primary production. The STC is identified as a unique habitat for fishes and as an important barrier to dispersal of species in the Southern Ocean. The present study has produced 18 new distributional records from the shelf waters of Tristan da Cunha and Gough Island. The fish fauna known from the shelf waters of these islands is reviewed, and a diagnosis, synonymy, and in some cases an illustration are provided. For certain species, brief notes on their biology, relative abundance and seasonal distribution are included. An analysis of the ichthyofaunal relationships between shallow water areas in the vicinity of the STC has resulted in the identification of a characteristic neritic STC ichthyofauna. The circumglobal distribution of many of these species is thought to be a consequence of a dispersive pelagic phase in their life-cycles. Biological processes in fishes at these islands are temporally and spatially affected by seasonal changes in oceanographic conditions. Seasonal sea temperature variation was identified as being an indicator of other oceanographic phenomena that may affect processes such as growth, reproduction and feeding in fishes at the islands. Most species have a summer spawning season and growth rate increased during the summer months. It was hypothesised that enhanced primary production and a related increase in food quality and availability during the summer were the major factors temporally regulating the growth and reproduction of fishes at the islands. Twenty families of neritic fishes have been recorded in the shelf waters of Tristan da Cunhaand Gough Island. Most families are represented by only one species. Because of this a wide range of life-history strategies are apparent in the fauna. Nevertheless, there are a number of common life-history characteristics shared by most of the neritic species. Firstly, the early lifehistory of many species included an extended pelagic phase which might have facilitated colonisation throughout the STC zone in the past, thereby regulating extant species diversity in this region. Secondly, the common occurrence of an extended summer breeding season and iteroparity suggested that these characters also contributed to survival in what is considered to be an unpredictable environment. It would appear that these common characteristics hold the key to the success of many fishes in the STC zone. This study has contributed to our understanding of oceanic island ecosystems and has revealed distributional patterns of fishes that were unknown previously. By focusing on the biological processes of selected species the regulatory role played by local environmental conditions became apparent. The results of this study are also relevant to proposed conservation measures for Tristan da Cunha and Gough Island.
- Full Text:
- Date Issued: 1993
Ethical decision-making in the therapeutic space : a psychoanalytic view
- Authors: Silove, Melanie
- Date: 2009
- Subjects: Decision making -- Moral and ethical aspects , Psychotherapy -- Moral and ethical aspects , Psychotherapists -- Professional ethics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3273 , http://hdl.handle.net/10962/d1020873
- Description: This study examined the ethical decision-making process as it transpired in the everyday context of the therapeutic space. In-depth interviews explored the subjective experiences of six South African psychologists, practicing as psychoanalytic psychotherapists, and their efforts to resolve real-life ethical dilemmas. The theoretical framework used to interpret the data subsumed professional literature in psychology on principle-based ethical decision-making as well as contemporary psychoanalytic debates on the phenomenon of countertransference enactments. A review of ethics codes, survey research and seminal decision-making frameworks suggests that ethical dilemmas have traditionally been resolved by recourse to an objective and impartial “principle ethics” perspective. Empirical evidence shows, however, that logical thinking and the rational application of codes, principles and standards are often insufficient to secure ethical action. The establishment of reflective space and the core theoretical notion of “ethical decision-making enactments” were proposed in order to address the subjective, irrational and unconscious dimension of professional decision-making. This study used a broadly hermeneutic research method which transformed participants‟ descriptions of engagement with real-life dilemmas into a psychoanalytically informed interpretive account of ethical decision-making. Twelve aspirational ethical principles were found to guide participants‟ daily analytic work. Beneficence was the principle most strongly identified with and nonmaleficence was the most neglected ethical principle. Unprocessed countertransference responses were shown to drive earlier prereflective phases of the ethical decision-making process. Mature ethical judgment was predicated upon the retrospective analysis of enactment phenomena. Dissatisfaction was expressed by all participants with regard to the role of professional resources in aiding the resolution of stressful ethical dilemmas. Risk factors for compromised professional decision-making included the paucity and perceived irrelevance of postgraduate ethics training, supervisory failure to confront the ethical and countertransference dimensions of common dilemmas and professional isolation. Rather than eliciting the hope of emotional support and greater insight, professional resources on the contrary mostly appeared to induce anxiety, mistrust and fearfulness. Based on the data and the literature, a pragmatic psychoanalytically informed ethical decision-making model was finally generated. The model, which considers both principle ethics as well as countertransference phenomena, offers a preliminary contribution to professional dialogue on the development and evaluation of empirically based decision-making frameworks. Practical recommendations are made for both the revision of the current South African ethics code and for improving the postqualifying ethics education of psychoanalytic practitioners and supervisors. The limitations of the data are discussed and directions for future research initiatives are proposed.
- Full Text:
- Date Issued: 2009
- Authors: Silove, Melanie
- Date: 2009
- Subjects: Decision making -- Moral and ethical aspects , Psychotherapy -- Moral and ethical aspects , Psychotherapists -- Professional ethics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3273 , http://hdl.handle.net/10962/d1020873
- Description: This study examined the ethical decision-making process as it transpired in the everyday context of the therapeutic space. In-depth interviews explored the subjective experiences of six South African psychologists, practicing as psychoanalytic psychotherapists, and their efforts to resolve real-life ethical dilemmas. The theoretical framework used to interpret the data subsumed professional literature in psychology on principle-based ethical decision-making as well as contemporary psychoanalytic debates on the phenomenon of countertransference enactments. A review of ethics codes, survey research and seminal decision-making frameworks suggests that ethical dilemmas have traditionally been resolved by recourse to an objective and impartial “principle ethics” perspective. Empirical evidence shows, however, that logical thinking and the rational application of codes, principles and standards are often insufficient to secure ethical action. The establishment of reflective space and the core theoretical notion of “ethical decision-making enactments” were proposed in order to address the subjective, irrational and unconscious dimension of professional decision-making. This study used a broadly hermeneutic research method which transformed participants‟ descriptions of engagement with real-life dilemmas into a psychoanalytically informed interpretive account of ethical decision-making. Twelve aspirational ethical principles were found to guide participants‟ daily analytic work. Beneficence was the principle most strongly identified with and nonmaleficence was the most neglected ethical principle. Unprocessed countertransference responses were shown to drive earlier prereflective phases of the ethical decision-making process. Mature ethical judgment was predicated upon the retrospective analysis of enactment phenomena. Dissatisfaction was expressed by all participants with regard to the role of professional resources in aiding the resolution of stressful ethical dilemmas. Risk factors for compromised professional decision-making included the paucity and perceived irrelevance of postgraduate ethics training, supervisory failure to confront the ethical and countertransference dimensions of common dilemmas and professional isolation. Rather than eliciting the hope of emotional support and greater insight, professional resources on the contrary mostly appeared to induce anxiety, mistrust and fearfulness. Based on the data and the literature, a pragmatic psychoanalytically informed ethical decision-making model was finally generated. The model, which considers both principle ethics as well as countertransference phenomena, offers a preliminary contribution to professional dialogue on the development and evaluation of empirically based decision-making frameworks. Practical recommendations are made for both the revision of the current South African ethics code and for improving the postqualifying ethics education of psychoanalytic practitioners and supervisors. The limitations of the data are discussed and directions for future research initiatives are proposed.
- Full Text:
- Date Issued: 2009
An inquiry into the incorporation of a multicultural approach in contemporary textbooks in South Africa
- Authors: Sharma, Anjali
- Date: 2001
- Subjects: Multicultural education -- South Africa Multicultural education -- Curricula Textbooks -- South Africa -- Evaluation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1579 , http://hdl.handle.net/10962/d1003461
- Description: During the past few decades a substantial body of research has emerged in western as well as the developing nations studying the racial bias in children's texts. However, it is only recently in South Africa, with the ascendance of the ANC government, that interest has been focused on eliminating apartheid values and on promoting multicultural tenets in the school curriculum. It is undeniable that the concept of multiculturalism has been severely stigmatised in the South African educational context. Anxieties have been expressed about embracing the discourse of multicultural education within the educational system based on fears that, like the previous educational system, it too will perpetuate group differences. Nevertheless, in recent years, a clear consensus view has emerged that the implementation of multicultural education is imperative if the goal of a rainbow South Africa is to be realised. Against this background, the present study attempts to study the incorporation of a multicultural approach into contemporary textbooks. To realise this aim I selected a sample of four textbooks, one from each of the major disciplines (science, English, geography and history), and SUbjected the texts and pictures from each to content analysis. The findings of this study suggest that a multicultural approach shall at least for the foreseeable future remain a central feature of learning materials produced for the new South African curricula. The findings indicate that multicultural aspects predominate in the texts as compared to other ideologies. This applies to both text content and illustrations. Contrary to the researcher's initial expectation, however, the texts also reveal a strong tendency towards Eurocentric and patriarchal approaches. This research does not conform to traditional, 'scientific' criteria of validity and reliability; it seeks only to investigate textbook material in more depth and thereby contribute to a more comprehensive understanding of the extent to which the texts subscribe to a multicultural approach. Such understanding may help both educationalists and authors in their evaluation of existing textbook material, and in the production of new texts which reflect the reality of South Africa as a multicultural society.
- Full Text:
- Date Issued: 2001
- Authors: Sharma, Anjali
- Date: 2001
- Subjects: Multicultural education -- South Africa Multicultural education -- Curricula Textbooks -- South Africa -- Evaluation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1579 , http://hdl.handle.net/10962/d1003461
- Description: During the past few decades a substantial body of research has emerged in western as well as the developing nations studying the racial bias in children's texts. However, it is only recently in South Africa, with the ascendance of the ANC government, that interest has been focused on eliminating apartheid values and on promoting multicultural tenets in the school curriculum. It is undeniable that the concept of multiculturalism has been severely stigmatised in the South African educational context. Anxieties have been expressed about embracing the discourse of multicultural education within the educational system based on fears that, like the previous educational system, it too will perpetuate group differences. Nevertheless, in recent years, a clear consensus view has emerged that the implementation of multicultural education is imperative if the goal of a rainbow South Africa is to be realised. Against this background, the present study attempts to study the incorporation of a multicultural approach into contemporary textbooks. To realise this aim I selected a sample of four textbooks, one from each of the major disciplines (science, English, geography and history), and SUbjected the texts and pictures from each to content analysis. The findings of this study suggest that a multicultural approach shall at least for the foreseeable future remain a central feature of learning materials produced for the new South African curricula. The findings indicate that multicultural aspects predominate in the texts as compared to other ideologies. This applies to both text content and illustrations. Contrary to the researcher's initial expectation, however, the texts also reveal a strong tendency towards Eurocentric and patriarchal approaches. This research does not conform to traditional, 'scientific' criteria of validity and reliability; it seeks only to investigate textbook material in more depth and thereby contribute to a more comprehensive understanding of the extent to which the texts subscribe to a multicultural approach. Such understanding may help both educationalists and authors in their evaluation of existing textbook material, and in the production of new texts which reflect the reality of South Africa as a multicultural society.
- Full Text:
- Date Issued: 2001
An investigation of learners' perceptions of homework in relation to the learning of mathematics : case studies in the northern townships of Port Elizabeth
- Authors: Wendt, Gabriele Erika
- Date: 2000
- Subjects: Homework -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Case studies Education and state -- South Africa Education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1635 , http://hdl.handle.net/10962/d1003517
- Description: Matriculation pass rates in South Africa, especially in Mathematics, have been poor. The literature and personal experience suggests that a problem with homework may be a factor in this. In order to discover how Port Elizabeth learners from ex-DET schools perceived and experienced Mathematics homework, and the nature of such homework, ten case studies of Grade 11 learners were done. While conducting and analyzing the case studies, a pattern emerged from the findings, which together with some new questions, needed to be explored on a larger sample population. In order to do this and to be able to generalize the findings, four follow-up studies in the form of surveys on Mathematics homework were conducted at nine schools. These studies involved a learner questionnaire, a teacher questionnaire, the timing of learners as they did set Mathematical problems and the analysis of common errors made by the learners while doing the problems. The findings revealed that learners received too little homework too infrequently and did it inefficiently and ineffectively. The learners worked too slowly, did not complete the homework, left out the difficult problems and made numerous unnecessary mistakes. However, most of the learners claimed to have enough time available to do their homework and spent approximately one hour on Mathematics homework when it had been assigned. Many of the misconceptions and the resultant errors originated from work that should have been well covered in previous grades. However, parts of the syllabi were omitted in previous grades and completion of the syllabus and homework was only seriously considered in Grade 12. Some implications of the findings for educational practice and further research are discussed.
- Full Text:
- Date Issued: 2000
- Authors: Wendt, Gabriele Erika
- Date: 2000
- Subjects: Homework -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Case studies Education and state -- South Africa Education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1635 , http://hdl.handle.net/10962/d1003517
- Description: Matriculation pass rates in South Africa, especially in Mathematics, have been poor. The literature and personal experience suggests that a problem with homework may be a factor in this. In order to discover how Port Elizabeth learners from ex-DET schools perceived and experienced Mathematics homework, and the nature of such homework, ten case studies of Grade 11 learners were done. While conducting and analyzing the case studies, a pattern emerged from the findings, which together with some new questions, needed to be explored on a larger sample population. In order to do this and to be able to generalize the findings, four follow-up studies in the form of surveys on Mathematics homework were conducted at nine schools. These studies involved a learner questionnaire, a teacher questionnaire, the timing of learners as they did set Mathematical problems and the analysis of common errors made by the learners while doing the problems. The findings revealed that learners received too little homework too infrequently and did it inefficiently and ineffectively. The learners worked too slowly, did not complete the homework, left out the difficult problems and made numerous unnecessary mistakes. However, most of the learners claimed to have enough time available to do their homework and spent approximately one hour on Mathematics homework when it had been assigned. Many of the misconceptions and the resultant errors originated from work that should have been well covered in previous grades. However, parts of the syllabi were omitted in previous grades and completion of the syllabus and homework was only seriously considered in Grade 12. Some implications of the findings for educational practice and further research are discussed.
- Full Text:
- Date Issued: 2000
Formulation development, manufacture and evaluation of a lamivudine-zidovudine nano co-crystal thermo-responsive suspension
- Authors: Witika, Bwalya Angel
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140546 , vital:37897 , http://dx.doi.org/10.21504/10962/140546
- Description: Expected release date-April 2021
- Full Text:
- Date Issued: 2020
- Authors: Witika, Bwalya Angel
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/140546 , vital:37897 , http://dx.doi.org/10.21504/10962/140546
- Description: Expected release date-April 2021
- Full Text:
- Date Issued: 2020
The enzymology of enhanced hydrolysis within the biosulphidogenic recycling sludge bed reactor (RSBR)
- Authors: Enongene, Godlove Nkwelle
- Date: 2004
- Subjects: Hydrolysis , Sewage sludge , Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4132 , http://hdl.handle.net/10962/d1015744
- Description: The hydrolysis of complex organic heteropolymers contained in municipal wastewater to simpler monomers by extracellular hydrolytic enzymes is generally considered the rate-limiting step of the biodegradation process. Previous studies of the Recycling Sludge Bed Reactor (RSBR) revealed that the hydrolysis of complex particulate organics, such as those contained in primary sludge (PS), was enhanced under anaerobic biosulphidogenic conditions. Although the mechanism was not fully understood, it appeared to involve the interaction of sulfide and sludge flocs. The current study was conducted using a 3500 ml laboratory-scale RSBR fed sieved PS at a loading rate of 0.5 kg COD/m³.day and an initial chemical oxygen demand (COD) to sulfate ratio (COD:SO₄) of 1:1. There was no significant accumulation of undigested sludge in the reactor over the 60-day experimental period and the quantity of SO₄ reduced indicated that the yield of soluble products from PS was at least as high as those reported previously for this system (> 50%). In the current study, the specific activities of a range of extracellular hydrolytic enzymes (L-alanine aminopeptidase, L-leucine aminopeptidase, arylsulphatase, α-glucosidase, β- glucosidase, protease and lipase) were monitored in a sulfide gradient within a biosulphidogenic RSBR. Data obtained indicated that the specific enzymatic activities increased with the depth of the RSBR and also correlated with a number of the physicochemical parameters including sulfide, alkalinity and sulfate. The activities of α- glucosidase and β-glucosidase were higher than that of the other enzymes studied. Lipase activity was relatively low and studies conducted on the enzyme-enzyme interaction using specific enzyme inhibitors indicated that lipases were probably being digested by the proteases. Further studies to determine the impact of sulfide on the enzymes, showed an increase in the enzyme activity with increasing sulfide concentration. Possible direct affects were investigated by looking for changes in the Michaelis constant (Km) and the maximal velocity (Vmax) of the crude enzymes with varying sulfide concentrations (250, 400 and 500 mg/l) using natural and synthetic substrates. The results showed no significant difference in both the Km and the Vmax for any of the hydrolytic enzymes except for the protease. The latter showed a statistically significant increase in the Km with increasing sulfide concentration. Although this indicated a direct interaction, this difference was not large enough to be of biochemical significance and was consequently not solely responsible for the enhanced hydrolysis observed in the RSBR. Investigation into the floc characteristics indicated that the biosulphidogenic RSBR flocs were generally small in size and became more dendritic with the depth of the RSBR. Based on the above data, the previously proposed descriptive models of enhanced hydrolysis of particulate organic matter in a biosulphidogenic RSBR has been revised. It is thought that the effect of sulfide on the hydrolysis step is primarily indirect and that the reduction in floc size and alteration of the floc shape to a more dendritic form is central to the success of the process.
- Full Text:
- Date Issued: 2004
- Authors: Enongene, Godlove Nkwelle
- Date: 2004
- Subjects: Hydrolysis , Sewage sludge , Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4132 , http://hdl.handle.net/10962/d1015744
- Description: The hydrolysis of complex organic heteropolymers contained in municipal wastewater to simpler monomers by extracellular hydrolytic enzymes is generally considered the rate-limiting step of the biodegradation process. Previous studies of the Recycling Sludge Bed Reactor (RSBR) revealed that the hydrolysis of complex particulate organics, such as those contained in primary sludge (PS), was enhanced under anaerobic biosulphidogenic conditions. Although the mechanism was not fully understood, it appeared to involve the interaction of sulfide and sludge flocs. The current study was conducted using a 3500 ml laboratory-scale RSBR fed sieved PS at a loading rate of 0.5 kg COD/m³.day and an initial chemical oxygen demand (COD) to sulfate ratio (COD:SO₄) of 1:1. There was no significant accumulation of undigested sludge in the reactor over the 60-day experimental period and the quantity of SO₄ reduced indicated that the yield of soluble products from PS was at least as high as those reported previously for this system (> 50%). In the current study, the specific activities of a range of extracellular hydrolytic enzymes (L-alanine aminopeptidase, L-leucine aminopeptidase, arylsulphatase, α-glucosidase, β- glucosidase, protease and lipase) were monitored in a sulfide gradient within a biosulphidogenic RSBR. Data obtained indicated that the specific enzymatic activities increased with the depth of the RSBR and also correlated with a number of the physicochemical parameters including sulfide, alkalinity and sulfate. The activities of α- glucosidase and β-glucosidase were higher than that of the other enzymes studied. Lipase activity was relatively low and studies conducted on the enzyme-enzyme interaction using specific enzyme inhibitors indicated that lipases were probably being digested by the proteases. Further studies to determine the impact of sulfide on the enzymes, showed an increase in the enzyme activity with increasing sulfide concentration. Possible direct affects were investigated by looking for changes in the Michaelis constant (Km) and the maximal velocity (Vmax) of the crude enzymes with varying sulfide concentrations (250, 400 and 500 mg/l) using natural and synthetic substrates. The results showed no significant difference in both the Km and the Vmax for any of the hydrolytic enzymes except for the protease. The latter showed a statistically significant increase in the Km with increasing sulfide concentration. Although this indicated a direct interaction, this difference was not large enough to be of biochemical significance and was consequently not solely responsible for the enhanced hydrolysis observed in the RSBR. Investigation into the floc characteristics indicated that the biosulphidogenic RSBR flocs were generally small in size and became more dendritic with the depth of the RSBR. Based on the above data, the previously proposed descriptive models of enhanced hydrolysis of particulate organic matter in a biosulphidogenic RSBR has been revised. It is thought that the effect of sulfide on the hydrolysis step is primarily indirect and that the reduction in floc size and alteration of the floc shape to a more dendritic form is central to the success of the process.
- Full Text:
- Date Issued: 2004
A gendered analysis of conditional cash based transfers: a case study of Puntland Technical Vocational Skills Training Programme, Somalia
- Authors: Chitombi, Rumbidzai
- Date: 2020
- Subjects: Puntland Technical Vocational Skills Training Programme , Transfer payments -- Somalia -- Case studies , Economic assistance, Domestic -- Somalia , Economic development -- Social aspects -- Somalia , Women -- Somalia -- Social conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167335 , vital:41469
- Description: As part of the worldwide development system, conditional cash transfer (CCT) programmes have become an increasingly popular policy and development approach in seeking to address poverty, especially in developing countries. Under the CCT programmes, beneficiaries are given assistance in the form of either cash or cash vouchers after fulfilling certain obligations of the development programme, such as attending training, enacting proper health care, or ensuring regular school attendance of children. The programmes have been described as a ‘double-edged sword’ since they aim to address poverty and, at the same time, reduce reliance on government largesse. In this regard, they are seen as potentially effective, and more empowering, alternatives to more traditional social assistance programmes whereby poor people receive welfare assistance in the form of ‘in kind’ and ‘unconditional’ assistance, receiving this as either food or shelter commodities, and without having to meet any conditions in doing so. This ‘traditional’ way of assisting poor people has largely been criticised for creating a dependency syndrome amongst the beneficiaries. In certain cases, CCT programmes focus specifically on women, either in receiving the cash transfer or in meeting the conditions attached to the programme, or both. In this context, considerable debate exists in the scholarly literature about the effects of such CCT programmes on the situation and status of women, specifically in terms of possibly empowering women. While some scholars claim that these programmes enhance the human and financial assets of women, others argue that focusing specifically on women, and as care-givers within households, tends to reproduce gender-based inequalities and subordination. Since gender equality and female empowerment are now key issues in global development spheres, and at national levels, this thesis aims to contribute to literature on the effects of CCTs on gender and women’s empowerment. This is pursued by way of a gendered perspective on CCTs as a development methodology for empowering women with reference to Somalia, using the Puntland Technical Vocational Skills Training programme as a case study. This programme focused, in the main, on internally-displaced people in Somalia, with a particular emphasis on women in meeting the programme conditions (i.e. participating in a training programme) and in being the cash recipients. The study used both quantitative and qualitative approaches for data collection and analysis, focusing on sixty selected beneficiaries who participated in the Puntland Technical Vocational skills training programme in Somalia from 2013. The thesis examines the prevailing structures (including cultural dynamics and socio-economic factors) in Somalia which lead to women’s subordination, notably in the light of significant internal displacement because of war and conflict and the emergence of internally-displaced camps. On this basis, from a gendered perspective, there is a critical appraisal of the manner in which the Puntland CCT programme affected women’s subordinate status, including how it may have led to the restructuring of gendered relations at both household and community levels. In offering this appraisal with reference to the Puntland programme, the thesis argues that women’s subordination and, by extension, women’s empowerment, is multi-faceted, and that continuity and change along the dimensions of subordination is often uneven and contradictory. Further, as also demonstrated in the Puntland case study, women’s subordination (as a social totality) is not a totalising system, such that women regularly make use of gaps in the system as opportunities to enhance their well-being without confronting the totality of the system.
- Full Text:
- Date Issued: 2020
- Authors: Chitombi, Rumbidzai
- Date: 2020
- Subjects: Puntland Technical Vocational Skills Training Programme , Transfer payments -- Somalia -- Case studies , Economic assistance, Domestic -- Somalia , Economic development -- Social aspects -- Somalia , Women -- Somalia -- Social conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167335 , vital:41469
- Description: As part of the worldwide development system, conditional cash transfer (CCT) programmes have become an increasingly popular policy and development approach in seeking to address poverty, especially in developing countries. Under the CCT programmes, beneficiaries are given assistance in the form of either cash or cash vouchers after fulfilling certain obligations of the development programme, such as attending training, enacting proper health care, or ensuring regular school attendance of children. The programmes have been described as a ‘double-edged sword’ since they aim to address poverty and, at the same time, reduce reliance on government largesse. In this regard, they are seen as potentially effective, and more empowering, alternatives to more traditional social assistance programmes whereby poor people receive welfare assistance in the form of ‘in kind’ and ‘unconditional’ assistance, receiving this as either food or shelter commodities, and without having to meet any conditions in doing so. This ‘traditional’ way of assisting poor people has largely been criticised for creating a dependency syndrome amongst the beneficiaries. In certain cases, CCT programmes focus specifically on women, either in receiving the cash transfer or in meeting the conditions attached to the programme, or both. In this context, considerable debate exists in the scholarly literature about the effects of such CCT programmes on the situation and status of women, specifically in terms of possibly empowering women. While some scholars claim that these programmes enhance the human and financial assets of women, others argue that focusing specifically on women, and as care-givers within households, tends to reproduce gender-based inequalities and subordination. Since gender equality and female empowerment are now key issues in global development spheres, and at national levels, this thesis aims to contribute to literature on the effects of CCTs on gender and women’s empowerment. This is pursued by way of a gendered perspective on CCTs as a development methodology for empowering women with reference to Somalia, using the Puntland Technical Vocational Skills Training programme as a case study. This programme focused, in the main, on internally-displaced people in Somalia, with a particular emphasis on women in meeting the programme conditions (i.e. participating in a training programme) and in being the cash recipients. The study used both quantitative and qualitative approaches for data collection and analysis, focusing on sixty selected beneficiaries who participated in the Puntland Technical Vocational skills training programme in Somalia from 2013. The thesis examines the prevailing structures (including cultural dynamics and socio-economic factors) in Somalia which lead to women’s subordination, notably in the light of significant internal displacement because of war and conflict and the emergence of internally-displaced camps. On this basis, from a gendered perspective, there is a critical appraisal of the manner in which the Puntland CCT programme affected women’s subordinate status, including how it may have led to the restructuring of gendered relations at both household and community levels. In offering this appraisal with reference to the Puntland programme, the thesis argues that women’s subordination and, by extension, women’s empowerment, is multi-faceted, and that continuity and change along the dimensions of subordination is often uneven and contradictory. Further, as also demonstrated in the Puntland case study, women’s subordination (as a social totality) is not a totalising system, such that women regularly make use of gaps in the system as opportunities to enhance their well-being without confronting the totality of the system.
- Full Text:
- Date Issued: 2020
Large scale spatio-temporal forcing of pelagic-coastal coupling: disentangling the effects of environmental change on intertidal invertebrate recruitment
- Authors: Muñiz, Carlota Fernández
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/75317 , vital:30400
- Description: Marine systems are driven by the relationships among organisms and environmental conditions. Anthropogenic-induced changes during the past decades have started to alter climatic drivers which have the potential to alter the physical, chemical and biological environment. In coastal systems, biogeography is influenced by the temporal variability in the conditions of the water mass. In addition, many marine benthic organisms develop in the water mass and rely on the conditions that link the pelagic and benthic systems for population maintenance. Such pelagic-coastal coupling indicates that changes in the trophic system during development can be transferred to the adult populations through changes in propagule supply. Thus, changes in environmental conditions can influence benthic populations directly (e.g. through larval advection) or indirectly, through their influence on the phytoplankton community (e.g. through the development of HABs). The South African coastline shows clear alongshore patterns of faunal biomass and species richness. On the south coast, strong longitudinal patterns of recruitment of intertidal organisms exist, with areas of particularly high recruitment. HABs of unprecedented spatio-temporal magnitude have recently developed along the south coast, including the areas where benthic recruitment is most intense. The present thesis used these blooms to study changes in intertidal recruitment directly or indirectly associated with their occurrence. Using a combination of remote sensing data to study the environmental conditions of the water mass in the innermost part of the Agulhas Bank, and estimates of mussel and barnacle recruitment rates to integrate the effects of conditions in the water mass during larval development, this thesis aimed to: (1) understand the conditions that triggered the development of an HAB of the dinoflagellate Lingulodinium polyedrum during summer of 2014, (2) determine the direct or indirect effects of that bloom on recruitment of intertidal organisms, and understand the factors that affect recruitment along the coast, (3) determine if the environmental factors during bloom development produced any carryover effects on recruit growth and mortality, and (4) determine the factors that drive changes in community biomass and composition along the south coast, the long-term trends in those factors, and possible changes experienced in recent years. Water column stability during spring, before the development of the red tide, followed by alternating periods of upwelling and relaxation during summer and autumn, seemed to promote the development and persistence of L. polyedrum. Recruitment of mussels and barnacles was estimated during the reproductive season of mussels in 2014, coinciding with the red tide, and during the following year. Alongshore patterns in recruitment were found, with higher mussel recruitment in the absence of the red tide and the opposite pattern in barnacles. Alongshore patterns in SST and chlorophyll matching those of recruitment were also found, with higher SSTs and lower chlorophyll during the red tide than the following year. Growth and mortality rates in barnacles did not differ between years during the first five months after settlement. This suggests that the factors which produced differences in recruitment between years did not produce carryover effects detectable at the temporal scales studied. Further analysis of 15 years of satellite-derived environmental data showed significant cooling trends potentially driven by a long-term seasonal acceleration of the Agulhas Current in autumn around two upwelling centres on the south coast, coinciding temporally with the reproductive period of mussels and barnacles, and spatially with the areas of highest recruitment. In addition, the comparison of SST and chl-a conditions during the first and the second half of the period of study showed that seasonality of both variables has changed in large areas over the shelf, with increasing importance of shorter-term variability, which would in turn decrease environmental predictability. Thus, the conditions observed during the present study, particularly during 2015, when upwelling seemed to be more intense, may presage the potential effects of identified long-term cooling trends at the upwelling centres. Although the general trend shows cooling around those areas, conditions can vary greatly among years, favouring different taxa. Changes in the Agulhas Current System are affected by changes in distant areas in the Indian Ocean basin. Such tele-connection is unlikely to be unique to this system and indicates the importance of understanding trends in major large scale climatic drivers and their regional effects in order to make predictions about coastal systems.
- Full Text:
- Date Issued: 2019
- Authors: Muñiz, Carlota Fernández
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/75317 , vital:30400
- Description: Marine systems are driven by the relationships among organisms and environmental conditions. Anthropogenic-induced changes during the past decades have started to alter climatic drivers which have the potential to alter the physical, chemical and biological environment. In coastal systems, biogeography is influenced by the temporal variability in the conditions of the water mass. In addition, many marine benthic organisms develop in the water mass and rely on the conditions that link the pelagic and benthic systems for population maintenance. Such pelagic-coastal coupling indicates that changes in the trophic system during development can be transferred to the adult populations through changes in propagule supply. Thus, changes in environmental conditions can influence benthic populations directly (e.g. through larval advection) or indirectly, through their influence on the phytoplankton community (e.g. through the development of HABs). The South African coastline shows clear alongshore patterns of faunal biomass and species richness. On the south coast, strong longitudinal patterns of recruitment of intertidal organisms exist, with areas of particularly high recruitment. HABs of unprecedented spatio-temporal magnitude have recently developed along the south coast, including the areas where benthic recruitment is most intense. The present thesis used these blooms to study changes in intertidal recruitment directly or indirectly associated with their occurrence. Using a combination of remote sensing data to study the environmental conditions of the water mass in the innermost part of the Agulhas Bank, and estimates of mussel and barnacle recruitment rates to integrate the effects of conditions in the water mass during larval development, this thesis aimed to: (1) understand the conditions that triggered the development of an HAB of the dinoflagellate Lingulodinium polyedrum during summer of 2014, (2) determine the direct or indirect effects of that bloom on recruitment of intertidal organisms, and understand the factors that affect recruitment along the coast, (3) determine if the environmental factors during bloom development produced any carryover effects on recruit growth and mortality, and (4) determine the factors that drive changes in community biomass and composition along the south coast, the long-term trends in those factors, and possible changes experienced in recent years. Water column stability during spring, before the development of the red tide, followed by alternating periods of upwelling and relaxation during summer and autumn, seemed to promote the development and persistence of L. polyedrum. Recruitment of mussels and barnacles was estimated during the reproductive season of mussels in 2014, coinciding with the red tide, and during the following year. Alongshore patterns in recruitment were found, with higher mussel recruitment in the absence of the red tide and the opposite pattern in barnacles. Alongshore patterns in SST and chlorophyll matching those of recruitment were also found, with higher SSTs and lower chlorophyll during the red tide than the following year. Growth and mortality rates in barnacles did not differ between years during the first five months after settlement. This suggests that the factors which produced differences in recruitment between years did not produce carryover effects detectable at the temporal scales studied. Further analysis of 15 years of satellite-derived environmental data showed significant cooling trends potentially driven by a long-term seasonal acceleration of the Agulhas Current in autumn around two upwelling centres on the south coast, coinciding temporally with the reproductive period of mussels and barnacles, and spatially with the areas of highest recruitment. In addition, the comparison of SST and chl-a conditions during the first and the second half of the period of study showed that seasonality of both variables has changed in large areas over the shelf, with increasing importance of shorter-term variability, which would in turn decrease environmental predictability. Thus, the conditions observed during the present study, particularly during 2015, when upwelling seemed to be more intense, may presage the potential effects of identified long-term cooling trends at the upwelling centres. Although the general trend shows cooling around those areas, conditions can vary greatly among years, favouring different taxa. Changes in the Agulhas Current System are affected by changes in distant areas in the Indian Ocean basin. Such tele-connection is unlikely to be unique to this system and indicates the importance of understanding trends in major large scale climatic drivers and their regional effects in order to make predictions about coastal systems.
- Full Text:
- Date Issued: 2019
A critical analysis of the grammar of isiXhosa as used in the Revised Union version of the Bible
- Oosthuysen, Jacobus Christiaan
- Authors: Oosthuysen, Jacobus Christiaan
- Date: 2013
- Subjects: Bible -- Xhosa -- Revised Union -- 1942 Xhosa language -- Grammar -- Research Xhosa language -- Texts
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3555 , http://hdl.handle.net/10962/d1001625
- Description: This study provides a description and critical analysis of the grammatical structure of isiXhosa as used in the Revised Union Version of the Bible, published in 1942 and republished in 1975. This translation records what was regarded as proper isiXhosa at the beginning of the 20th century, reflecting the consensus inter alia of prominent isiXhosa writers, such as W.B. Rubusana, J.H. Soga, C. Koti, Y. Mbali and D. D. T. Jabavu, who served on the committee that produced the revision. In this study isiXhosa is described in its own right, without approaching it with preconceived ideas derived from other languages. That is to say this is a phenomenological analysis describing the grammatical structures of isiXhosa as they present themselves to the analyst. It is comprehensive, with no structure being overlooked or being described in such a manner that it complicates an understanding of other structures. In the first chapter the context of the research and a brief outline of the historical growth in understanding the structure of isiXhosa are set out and the goals and the method followed in this study are described. In the following chapters the findings of this study are presented. The initial focus is on isiXhosa phonology and the orthography used to put it to writing. Then isiXhosa morphology and syntax is set out. Initially the substantives, i.e. the nouns and pronouns in their distinctive classes and forms, and how they are qualified, receive attention. Then the predicates are explored, i.e. the verbs and copulatives, as linked to the substantives with concords, and reflecting various moods, tenses, actualities and aspects. Finally attention is given to ideophones and interjections and words that can be grouped together as adverbs, conjunctions, avoidance words and numerals. In the concluding chapter consideration is given to the question of whether this study has in fact achieved the aim of setting out a description of the structure of isiXhosa based solely on the language itself, free of preconceived ideas, and attention is drawn to insights gained in respect of the true nature of the isiXhosa grammatical structures, such as, for example, the variable prefix qualificative nouns, traditionally referred to as adjectives. This study is therefore a revisionist study in the sense that it reinvents isiXhosa as a language in its own right, free from Western influenced perspectives.
- Full Text:
- Date Issued: 2013
- Authors: Oosthuysen, Jacobus Christiaan
- Date: 2013
- Subjects: Bible -- Xhosa -- Revised Union -- 1942 Xhosa language -- Grammar -- Research Xhosa language -- Texts
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3555 , http://hdl.handle.net/10962/d1001625
- Description: This study provides a description and critical analysis of the grammatical structure of isiXhosa as used in the Revised Union Version of the Bible, published in 1942 and republished in 1975. This translation records what was regarded as proper isiXhosa at the beginning of the 20th century, reflecting the consensus inter alia of prominent isiXhosa writers, such as W.B. Rubusana, J.H. Soga, C. Koti, Y. Mbali and D. D. T. Jabavu, who served on the committee that produced the revision. In this study isiXhosa is described in its own right, without approaching it with preconceived ideas derived from other languages. That is to say this is a phenomenological analysis describing the grammatical structures of isiXhosa as they present themselves to the analyst. It is comprehensive, with no structure being overlooked or being described in such a manner that it complicates an understanding of other structures. In the first chapter the context of the research and a brief outline of the historical growth in understanding the structure of isiXhosa are set out and the goals and the method followed in this study are described. In the following chapters the findings of this study are presented. The initial focus is on isiXhosa phonology and the orthography used to put it to writing. Then isiXhosa morphology and syntax is set out. Initially the substantives, i.e. the nouns and pronouns in their distinctive classes and forms, and how they are qualified, receive attention. Then the predicates are explored, i.e. the verbs and copulatives, as linked to the substantives with concords, and reflecting various moods, tenses, actualities and aspects. Finally attention is given to ideophones and interjections and words that can be grouped together as adverbs, conjunctions, avoidance words and numerals. In the concluding chapter consideration is given to the question of whether this study has in fact achieved the aim of setting out a description of the structure of isiXhosa based solely on the language itself, free of preconceived ideas, and attention is drawn to insights gained in respect of the true nature of the isiXhosa grammatical structures, such as, for example, the variable prefix qualificative nouns, traditionally referred to as adjectives. This study is therefore a revisionist study in the sense that it reinvents isiXhosa as a language in its own right, free from Western influenced perspectives.
- Full Text:
- Date Issued: 2013
The child witness in the accusatorial system
- Authors: Müller, Karen, 1964-
- Date: 1998
- Subjects: Child witnesses , Children -- Legal status, laws, etc. , Child witnesses -- South Africa , Evidence (Law)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3715 , http://hdl.handle.net/10962/d1007708 , Child witnesses , Children -- Legal status, laws, etc. , Child witnesses -- South Africa , Evidence (Law)
- Description: For the purpose of this study tbe child witness in the accusatorial system will be viewed as a source of information. When a witness gives evidence in court, the function of the witness is to provide the court with certain information. A number of crucial questions arise when the witness is a child. Do children bave the ability to remember and relate an event accurately? Are children prone to suggestion and fantasy? What effect, if any, does the court environment have on a child 's ability to convey information? What perceptions do children have about the legal process, and how do these perceptions affect their ability to testify? Do adults influence the information which children impart by the techniques they employ to obtain such information? Accepting the hypothesis that child witnesses are sources of information, the purpose of this study is to evaluate all aspects of the criminal justice system relating to child witnesses as well as available research on children to determine whether it is possible to obtain reliable and accurate information from children. Proposals will be formulated regarding the most successful methods of obtaining reliable and accurate information from children, and how these can be adapted for use by the legal system. The purpose of the study is to develop an approach to children in the legal system that will be fair to children while at the same time protecting the rights of the accused, and which will lead to a successful method of obtaining accurate information.
- Full Text:
- Date Issued: 1998
- Authors: Müller, Karen, 1964-
- Date: 1998
- Subjects: Child witnesses , Children -- Legal status, laws, etc. , Child witnesses -- South Africa , Evidence (Law)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3715 , http://hdl.handle.net/10962/d1007708 , Child witnesses , Children -- Legal status, laws, etc. , Child witnesses -- South Africa , Evidence (Law)
- Description: For the purpose of this study tbe child witness in the accusatorial system will be viewed as a source of information. When a witness gives evidence in court, the function of the witness is to provide the court with certain information. A number of crucial questions arise when the witness is a child. Do children bave the ability to remember and relate an event accurately? Are children prone to suggestion and fantasy? What effect, if any, does the court environment have on a child 's ability to convey information? What perceptions do children have about the legal process, and how do these perceptions affect their ability to testify? Do adults influence the information which children impart by the techniques they employ to obtain such information? Accepting the hypothesis that child witnesses are sources of information, the purpose of this study is to evaluate all aspects of the criminal justice system relating to child witnesses as well as available research on children to determine whether it is possible to obtain reliable and accurate information from children. Proposals will be formulated regarding the most successful methods of obtaining reliable and accurate information from children, and how these can be adapted for use by the legal system. The purpose of the study is to develop an approach to children in the legal system that will be fair to children while at the same time protecting the rights of the accused, and which will lead to a successful method of obtaining accurate information.
- Full Text:
- Date Issued: 1998
Assembly of Omegatetravirus virus-like particles in the yeast Saccharomyces cerevisiae
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
Risk-based assessment of environmental asbestos contamination in the Northern Cape and North West provinces of South Africa
- Authors: Jones, Robert Ryan
- Date: 2011
- Subjects: Asbestos industry -- Health aspects -- South Africa -- Northern Cape Asbestos industry -- Health aspects -- South Africa -- North West Environmental risk assessment -- South Africa-- Northern Cape Environmental risk assessment -- North West Asbestos -- Toxicology -- South Africa -- Northern Cape Asbestos -- Toxicology -- South Africa -- North West Tailings (Metallurgy) -- Waste disposal -- South Africa -- Northern Cape Tailings (Metallurgy) -- Waste disposal -- South Africa -- North West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4780 , http://hdl.handle.net/10962/d1012612
- Description: The commercial mining of asbestos occurred in four Provinces of South Africa (Northern Cape, North West, Limpopo and Mpumalanga). It was initiated in the late 1800's and lasted for over a hundred years into the beginning of this century. As a producer of amphibole asbestos, South Africa far outpaced every other country being responsible for 97% of global production. The last crocidolite mine closed in 1996 and chrysotile in 2002. Anecdotal information concerning environmental contamination as a result of the former mining activities and the improper disposal of mine waste tailings has been reported by a variety of authors. Few comprehensive or systematic surveys have been conducted to date to document this issue and very little quantifiable research has been completed on the communities located in close proximity to the former mine sites to determine the extent of contamination. In 2004-2006 communities were surveyed within the Northern Cape and North West Provinces to determine the extent and severity of environmental contamination. This research developed and applied a methodology to select those communities suspected of environmental contamination, a targeted survey methodology, and a protocol for rapid sample laboratory analysis. A total of 41 communities were initially predicted by the model to be suspected for environmental asbestos contamination. Based on the inclusion of local knowledge, a final 36 communities were selected for a screening-level field assessment, 34 of which were found to contain environmental asbestos contamination at rates ranging from 20 to 100% of the surveyed locations. A total of 1 843 samples of soil and building material were collected in the screening level assessment. One community (Ga-Mopedi) was selected as being representative of the total cohort and a more detailed house to house survey was completed. A total of 1 486 samples were collected during the detailed survey. Results of the detailed survey revealed 26.2% of the homes were contaminated with asbestos containing soil and/or building material. A theoretical quantitative cumulative exposure assessment was developed to estimate the disease burden within the study area population of 126,130 individuals within the surveyed communities resulting in a predicted range of 25-52.4 excess deaths per year from lung cancer and mesothelioma due solely to environmental exposures to asbestos pollution.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Robert Ryan
- Date: 2011
- Subjects: Asbestos industry -- Health aspects -- South Africa -- Northern Cape Asbestos industry -- Health aspects -- South Africa -- North West Environmental risk assessment -- South Africa-- Northern Cape Environmental risk assessment -- North West Asbestos -- Toxicology -- South Africa -- Northern Cape Asbestos -- Toxicology -- South Africa -- North West Tailings (Metallurgy) -- Waste disposal -- South Africa -- Northern Cape Tailings (Metallurgy) -- Waste disposal -- South Africa -- North West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4780 , http://hdl.handle.net/10962/d1012612
- Description: The commercial mining of asbestos occurred in four Provinces of South Africa (Northern Cape, North West, Limpopo and Mpumalanga). It was initiated in the late 1800's and lasted for over a hundred years into the beginning of this century. As a producer of amphibole asbestos, South Africa far outpaced every other country being responsible for 97% of global production. The last crocidolite mine closed in 1996 and chrysotile in 2002. Anecdotal information concerning environmental contamination as a result of the former mining activities and the improper disposal of mine waste tailings has been reported by a variety of authors. Few comprehensive or systematic surveys have been conducted to date to document this issue and very little quantifiable research has been completed on the communities located in close proximity to the former mine sites to determine the extent of contamination. In 2004-2006 communities were surveyed within the Northern Cape and North West Provinces to determine the extent and severity of environmental contamination. This research developed and applied a methodology to select those communities suspected of environmental contamination, a targeted survey methodology, and a protocol for rapid sample laboratory analysis. A total of 41 communities were initially predicted by the model to be suspected for environmental asbestos contamination. Based on the inclusion of local knowledge, a final 36 communities were selected for a screening-level field assessment, 34 of which were found to contain environmental asbestos contamination at rates ranging from 20 to 100% of the surveyed locations. A total of 1 843 samples of soil and building material were collected in the screening level assessment. One community (Ga-Mopedi) was selected as being representative of the total cohort and a more detailed house to house survey was completed. A total of 1 486 samples were collected during the detailed survey. Results of the detailed survey revealed 26.2% of the homes were contaminated with asbestos containing soil and/or building material. A theoretical quantitative cumulative exposure assessment was developed to estimate the disease burden within the study area population of 126,130 individuals within the surveyed communities resulting in a predicted range of 25-52.4 excess deaths per year from lung cancer and mesothelioma due solely to environmental exposures to asbestos pollution.
- Full Text:
- Date Issued: 2011
Photophysiochemical studies of d¹⁰ metallophthalocyanines and their interaction with nanoparticles
- Chidawanyika, Wadzanai Janet Upenyu
- Authors: Chidawanyika, Wadzanai Janet Upenyu
- Date: 2010
- Subjects: Nanoparticles Phthalocyanines Photochemistry Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4335 , http://hdl.handle.net/10962/d1004996
- Description: The syntheses, extensive spectroscopic characterization, photophysical and photochemical studies have been conducted for a variation of d10 metallophthaloycanines (MPcs). Comparisons have been made taking into consideration the nfluence of the central metal ion, solvent properties, substituent type and position. Coordination to heavy central metals i.e. Hg gives enhanced triplet state properties. Low symmetry metallophthalocyanine complexes were similarly haracterized and the influence of nteractions with nanoparticles on their photophysical and photochemical properties determined. The MPcs have been linked and adsorbed or mixed with nanoparticles i.e. hemically functionalized single-walled carbon nanotubes SWCNT) and mercaptocarboxylic acid capped CdTe quantum dots (QDs) and changes in the spectra accounted for with respect to the proposed conjugate structures. Distinct differences ccur for linked and adsorbed or mixed conjugates in the bsorption, infrared (IR) and Raman spectra and for thermal ravimetric decay profiles, suggesting successful formation f covalent bonds (linked) and point to structurally ifferent materials. SWCNT quench MPc fluorescence by a photoinduced electron transfer mediated process to give low fluorescence quantum yields. The QDs were used as energy transfer donors and facilitate energy transfer, through Förster resonance energy transfer (FRET) from the QDs to the MPcs. Improved FRET efficiencies were found for linked MPc-QD conjugates relative to the mixed species. Photophysicochemical properties of MPcs were, in general, improved as a result of interactions with nanoparticles.
- Full Text:
- Date Issued: 2010
- Authors: Chidawanyika, Wadzanai Janet Upenyu
- Date: 2010
- Subjects: Nanoparticles Phthalocyanines Photochemistry Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4335 , http://hdl.handle.net/10962/d1004996
- Description: The syntheses, extensive spectroscopic characterization, photophysical and photochemical studies have been conducted for a variation of d10 metallophthaloycanines (MPcs). Comparisons have been made taking into consideration the nfluence of the central metal ion, solvent properties, substituent type and position. Coordination to heavy central metals i.e. Hg gives enhanced triplet state properties. Low symmetry metallophthalocyanine complexes were similarly haracterized and the influence of nteractions with nanoparticles on their photophysical and photochemical properties determined. The MPcs have been linked and adsorbed or mixed with nanoparticles i.e. hemically functionalized single-walled carbon nanotubes SWCNT) and mercaptocarboxylic acid capped CdTe quantum dots (QDs) and changes in the spectra accounted for with respect to the proposed conjugate structures. Distinct differences ccur for linked and adsorbed or mixed conjugates in the bsorption, infrared (IR) and Raman spectra and for thermal ravimetric decay profiles, suggesting successful formation f covalent bonds (linked) and point to structurally ifferent materials. SWCNT quench MPc fluorescence by a photoinduced electron transfer mediated process to give low fluorescence quantum yields. The QDs were used as energy transfer donors and facilitate energy transfer, through Förster resonance energy transfer (FRET) from the QDs to the MPcs. Improved FRET efficiencies were found for linked MPc-QD conjugates relative to the mixed species. Photophysicochemical properties of MPcs were, in general, improved as a result of interactions with nanoparticles.
- Full Text:
- Date Issued: 2010
Termination of psychotherapy : a phenomenological exploration of the therapist's and the patient's experience
- Authors: Schlodder, Michelle Ingrid
- Date: 1997
- Subjects: Psychotherapy -- termination Psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3049 , http://hdl.handle.net/10962/d1002558
- Full Text:
- Date Issued: 1997
- Authors: Schlodder, Michelle Ingrid
- Date: 1997
- Subjects: Psychotherapy -- termination Psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3049 , http://hdl.handle.net/10962/d1002558
- Full Text:
- Date Issued: 1997
The poetry of N.H. Brettell : a critical edition
- Authors: Hacksley, Reginald Gregory
- Date: 2006
- Subjects: Brettell, N H -- Criticism and interpretation South African poetry (English) -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2289 , http://hdl.handle.net/10962/d1008072
- Description: This thesis presents for the first time a critical reading edition of all known poems by N. H. Brettell. It makes no claim to being definitive, nor does it attempt to establish a final text. It represents merely the best thinking of the editor. Brettell printed and circulated his poetry primarily in hand-made illustrated volumes in a process reminiscent of the scribal publication of the seventeenth century. Only 137 of his 206 extant poems were commercially published during his lifetime. In this study all known printed versions of Brettell's poetry whether in privately printed or commercially published form were examined. All variant readings were recorded and are shown. Wherever possible the relationships between texts are also noted. The poems in this edition are ordered in each case according to the version in the latest datable privately produced collection. The commentary and critical introduction were compiled with the general reader in mind. No previous familiarity with southern African fauna and flora is assumed: animals, birds and insects are described and their scientific names supplied. Expressions current in ordinary British or South African English and present in non-specialist dictionaries are not glossed, but archaic and dialectal forms felt to require explication are briefly explained. So too are less familiar South African dialectal expressions which have been assimilated into the South African English lexicon. Intertextual, Christian and mythological references, both African and Western, are annotated in an attempt to make such references accessible to readers who may not share Brettell's cultural background. The intention is to close the changing distance between the text and the audience. An essay discussing the merits, potential and limitations of electronic scholarly editing is included as part of the textual introduction. A CD-Rom containing Brettell's watercolour illustrations in his privately produced collections and audio-clips of him reading his poetry accompanies this thesis.
- Full Text:
- Date Issued: 2006
- Authors: Hacksley, Reginald Gregory
- Date: 2006
- Subjects: Brettell, N H -- Criticism and interpretation South African poetry (English) -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2289 , http://hdl.handle.net/10962/d1008072
- Description: This thesis presents for the first time a critical reading edition of all known poems by N. H. Brettell. It makes no claim to being definitive, nor does it attempt to establish a final text. It represents merely the best thinking of the editor. Brettell printed and circulated his poetry primarily in hand-made illustrated volumes in a process reminiscent of the scribal publication of the seventeenth century. Only 137 of his 206 extant poems were commercially published during his lifetime. In this study all known printed versions of Brettell's poetry whether in privately printed or commercially published form were examined. All variant readings were recorded and are shown. Wherever possible the relationships between texts are also noted. The poems in this edition are ordered in each case according to the version in the latest datable privately produced collection. The commentary and critical introduction were compiled with the general reader in mind. No previous familiarity with southern African fauna and flora is assumed: animals, birds and insects are described and their scientific names supplied. Expressions current in ordinary British or South African English and present in non-specialist dictionaries are not glossed, but archaic and dialectal forms felt to require explication are briefly explained. So too are less familiar South African dialectal expressions which have been assimilated into the South African English lexicon. Intertextual, Christian and mythological references, both African and Western, are annotated in an attempt to make such references accessible to readers who may not share Brettell's cultural background. The intention is to close the changing distance between the text and the audience. An essay discussing the merits, potential and limitations of electronic scholarly editing is included as part of the textual introduction. A CD-Rom containing Brettell's watercolour illustrations in his privately produced collections and audio-clips of him reading his poetry accompanies this thesis.
- Full Text:
- Date Issued: 2006
The population dynamics of the rock hyrax procavia capensis (Pallas, 1766) in the Mountain Zebra National Park
- Authors: Fourie, Leon Johan
- Date: 1984
- Subjects: Rock hyrax Mountain Zebra National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5743 , http://hdl.handle.net/10962/d1005429
- Description: The chief objective of the study was to investigate the population dynamics of the hyrax in the Mountain Zebra National Park (MZNP). To realise this objective information on growth, age determination, reproduction, habitat utilization, behaviour, parasites and mortality had to be gathered. The growth of hyrax in relation to age is described by means of Stevens asymptotic regression equations. Near asymptotic measurements are attained first in hind foot length (at 30-33 months of age), head/body length (at 37-39 months of age), girth (at 41-48 months of age) and body mass (at 68-70 months of age). Allometric growth of the various body measurements was investigated and useful predictive relationships for mass are presented. Age determination of hyrax was studied in detail. Cementum annuli counts provided reliable estimates of age. One primary cementum line is formed annually. The dried eye lens mass was an accurate means of age determination up to c. 72 months of age. A summary of findings which will facilitate age determination of dead animals or skulls, and live animals, is provided. Reproduction in the hyrax was studied with emphasis on breeding season, age-specific litter sizes, prenatal mortality and lactation. Male hyrax attained puberty at 15-17 months of age or one year later. Females generally attained puberty at 15-17 months of age. One female (1,4% of total shot sample for the specific age group) attained puberty at 4-5 months of age. Middle-aged hyrax had significantly larger litter sizes than younger animals. Hyrax in the MZNP feed on at least 80 different plant species belonging to 33 plant families. Crude protein of stomach contents and faecal samples showed little seasonal fluctuation implying that hyrax in the MZNP were on a stable quality diet. Female hyrax enjoyed a significantly better quality diet than males for the four month period prior to parturition and during the first two months of lactation. The crude protein values of faecal and stomach samples had a significant correlation. Body fat of male and female hyrax showed seasonal variation related to physiologically stressful periods. Seasonal differences in activity patterns were demonstrated. The basic structure of hyrax social organization is the multi-female kinship group that is matrilocal. Territorial dominant males maintain harems and exclude all other adult males. Peripheral males occupy areas on the periphery of the activity areas of other members of the hyrax colony. Peripheral males do not form bachelor groups and are normally younger than territorial males. It is suggested that territorial males are able to monopolize between 3-17 females in a successful and energetic manner. Both natal and breeding dispersal occurred, the former being considerably more extensive than the latter. The ecto- and endoparasites of hyrax were identified and their burdens quantified over a 13 month period. Juveniles had significantly larger burdens of ectoparasites than did adults. Information on age-specific mortality was obtained from skulls collected in the field and at black eagles' nests. Losses that occurred in the study population due to caracal and black eagle predation were quantified. Evidence is supplied which indicates that juvenile mortality may fluctuate markedly. The population dynamics of the hyrax population in the MZNP was studied by the use of time specific life-tables, models on population growth rates, population simulation models and sensitivity analysis. Sensitivity coefficients were used as a predictor of population regulation. Female juvenile mortality was considered to be the main regulating factor. Changes in fecundity schedule are important compensatory mechanisms and also play an important role in the regulation of a hyrax population. Predation, particularly by caracal, is thought to dampen population fluctuations.
- Full Text:
- Date Issued: 1984
- Authors: Fourie, Leon Johan
- Date: 1984
- Subjects: Rock hyrax Mountain Zebra National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5743 , http://hdl.handle.net/10962/d1005429
- Description: The chief objective of the study was to investigate the population dynamics of the hyrax in the Mountain Zebra National Park (MZNP). To realise this objective information on growth, age determination, reproduction, habitat utilization, behaviour, parasites and mortality had to be gathered. The growth of hyrax in relation to age is described by means of Stevens asymptotic regression equations. Near asymptotic measurements are attained first in hind foot length (at 30-33 months of age), head/body length (at 37-39 months of age), girth (at 41-48 months of age) and body mass (at 68-70 months of age). Allometric growth of the various body measurements was investigated and useful predictive relationships for mass are presented. Age determination of hyrax was studied in detail. Cementum annuli counts provided reliable estimates of age. One primary cementum line is formed annually. The dried eye lens mass was an accurate means of age determination up to c. 72 months of age. A summary of findings which will facilitate age determination of dead animals or skulls, and live animals, is provided. Reproduction in the hyrax was studied with emphasis on breeding season, age-specific litter sizes, prenatal mortality and lactation. Male hyrax attained puberty at 15-17 months of age or one year later. Females generally attained puberty at 15-17 months of age. One female (1,4% of total shot sample for the specific age group) attained puberty at 4-5 months of age. Middle-aged hyrax had significantly larger litter sizes than younger animals. Hyrax in the MZNP feed on at least 80 different plant species belonging to 33 plant families. Crude protein of stomach contents and faecal samples showed little seasonal fluctuation implying that hyrax in the MZNP were on a stable quality diet. Female hyrax enjoyed a significantly better quality diet than males for the four month period prior to parturition and during the first two months of lactation. The crude protein values of faecal and stomach samples had a significant correlation. Body fat of male and female hyrax showed seasonal variation related to physiologically stressful periods. Seasonal differences in activity patterns were demonstrated. The basic structure of hyrax social organization is the multi-female kinship group that is matrilocal. Territorial dominant males maintain harems and exclude all other adult males. Peripheral males occupy areas on the periphery of the activity areas of other members of the hyrax colony. Peripheral males do not form bachelor groups and are normally younger than territorial males. It is suggested that territorial males are able to monopolize between 3-17 females in a successful and energetic manner. Both natal and breeding dispersal occurred, the former being considerably more extensive than the latter. The ecto- and endoparasites of hyrax were identified and their burdens quantified over a 13 month period. Juveniles had significantly larger burdens of ectoparasites than did adults. Information on age-specific mortality was obtained from skulls collected in the field and at black eagles' nests. Losses that occurred in the study population due to caracal and black eagle predation were quantified. Evidence is supplied which indicates that juvenile mortality may fluctuate markedly. The population dynamics of the hyrax population in the MZNP was studied by the use of time specific life-tables, models on population growth rates, population simulation models and sensitivity analysis. Sensitivity coefficients were used as a predictor of population regulation. Female juvenile mortality was considered to be the main regulating factor. Changes in fecundity schedule are important compensatory mechanisms and also play an important role in the regulation of a hyrax population. Predation, particularly by caracal, is thought to dampen population fluctuations.
- Full Text:
- Date Issued: 1984
Urban agriculture: advocacy and practice: a discursive study with particular reference to three Eastern Cape centres
- Authors: Webb, Nigel Leigh
- Date: 1997
- Subjects: Urban agriculture -- South Africa -- Eastern Cape Land use, Urban -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2095 , http://hdl.handle.net/10962/d1002658
- Description: The purpose of this thesis is to explain the continued advocacy of 'urban agriculture' (UA) in the literature in the face of the seemingly modest role played by cultivation in practice. The analytical framework adopted isrthat of discourse, the theoretical underpinnings of which are derived from the early works of Foucault, and applications such as those of Escobar (1989; 1991) and Ferguson (1990). Using a discursive orientation involves two main tasks - an explanation of how 'UA' has gained some prominence and the man~er in which its currency is able to be maintained. The investigation included an in-depth analysis of the literature and empirical research in th!"e~Eastern Cape centres. The function of the empirical findings is to expose the discourse, as well as to extend the empirical base relating to 'urban agricultural' research in general. The thesis suggests that the growth in interest in 'UA' is a result of a Foucaultian "gap" opening in the discourse. Changes in the conceptualisation of development, the rise-in prominence of the urban poor and emerging ecodevelopment views, among others, have given proponents of "UA' greater room for manoeuvre. However, most case studies promote 'UA' despite providing little evidence of its role in household welfare. The way the discourse maintains its' currency is in the manner in which the objects of 'UA' are constituted. Firstly, the people are characterised as poor, largely divorced from their rural origins, and mainly female. Each of these assertions is questioned on the basis of the literature itself and the empirical findings. Secondly, in the practice of cultivation, emphasis is placed on the inputs used, and the crops that are produced. The treatment of both the inputs and the crops by the literature is cursory. Investigations show that land availability, garden size and irrigation water are e~pecially problematic and vegetable consumption remains low. Four types of alleged benefit associated with 'UA' are analysed - environmental and ecological, psychological and social, financial, and nutritional. In each case commonly held assumptions are undermined by closer investigation. Thus, the thesis contends that the role played by cultivation is a modest one. Most of the claims made on behalf of 'UA' are more congruent with development discourse than actual cultivation practice.
- Full Text:
- Date Issued: 1997
- Authors: Webb, Nigel Leigh
- Date: 1997
- Subjects: Urban agriculture -- South Africa -- Eastern Cape Land use, Urban -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2095 , http://hdl.handle.net/10962/d1002658
- Description: The purpose of this thesis is to explain the continued advocacy of 'urban agriculture' (UA) in the literature in the face of the seemingly modest role played by cultivation in practice. The analytical framework adopted isrthat of discourse, the theoretical underpinnings of which are derived from the early works of Foucault, and applications such as those of Escobar (1989; 1991) and Ferguson (1990). Using a discursive orientation involves two main tasks - an explanation of how 'UA' has gained some prominence and the man~er in which its currency is able to be maintained. The investigation included an in-depth analysis of the literature and empirical research in th!"e~Eastern Cape centres. The function of the empirical findings is to expose the discourse, as well as to extend the empirical base relating to 'urban agricultural' research in general. The thesis suggests that the growth in interest in 'UA' is a result of a Foucaultian "gap" opening in the discourse. Changes in the conceptualisation of development, the rise-in prominence of the urban poor and emerging ecodevelopment views, among others, have given proponents of "UA' greater room for manoeuvre. However, most case studies promote 'UA' despite providing little evidence of its role in household welfare. The way the discourse maintains its' currency is in the manner in which the objects of 'UA' are constituted. Firstly, the people are characterised as poor, largely divorced from their rural origins, and mainly female. Each of these assertions is questioned on the basis of the literature itself and the empirical findings. Secondly, in the practice of cultivation, emphasis is placed on the inputs used, and the crops that are produced. The treatment of both the inputs and the crops by the literature is cursory. Investigations show that land availability, garden size and irrigation water are e~pecially problematic and vegetable consumption remains low. Four types of alleged benefit associated with 'UA' are analysed - environmental and ecological, psychological and social, financial, and nutritional. In each case commonly held assumptions are undermined by closer investigation. Thus, the thesis contends that the role played by cultivation is a modest one. Most of the claims made on behalf of 'UA' are more congruent with development discourse than actual cultivation practice.
- Full Text:
- Date Issued: 1997