Investigation into the technical feasibility of biological treatment of precious metal refining wastewater
- Authors: Moore, Bronwyn Ann
- Date: 2013
- Subjects: Sewage -- Purification -- Biological treatment -- South Africa Sewage -- Purification -- Activated sludge process -- South Africa Water reuse -- South Africa Flotation -- South Africa Platinum mines and mining -- Waste disposal -- South Africa Platinum mines and mining -- Economic aspects -- South Africa Mine water -- Environmental aspects -- South Africa Platinum mines and mining -- Waste minimization -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3888 , http://hdl.handle.net/10962/d1002013
- Description: The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.
- Full Text:
- Date Issued: 2013
- Authors: Moore, Bronwyn Ann
- Date: 2013
- Subjects: Sewage -- Purification -- Biological treatment -- South Africa Sewage -- Purification -- Activated sludge process -- South Africa Water reuse -- South Africa Flotation -- South Africa Platinum mines and mining -- Waste disposal -- South Africa Platinum mines and mining -- Economic aspects -- South Africa Mine water -- Environmental aspects -- South Africa Platinum mines and mining -- Waste minimization -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3888 , http://hdl.handle.net/10962/d1002013
- Description: The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.
- Full Text:
- Date Issued: 2013
Representation and use of indigenous heritage constructs : implications for the quality and relevance of heritage education in post colonial southern Africa
- Authors: Zazu, Cryton
- Date: 2013
- Subjects: Albany Museum (Grahamstown, South Africa) Cultural property -- Conservation and restoration -- Research -- Africa, Southern Great Zimbabwe (Extinct city) Indigenous peoples -- Material culture -- Africa, Southern Anthropological museums and collections -- Management -- Research -- Africa, Southern Cultural property -- Management -- Research Ethnoscience -- Study and teaching -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1407 , http://hdl.handle.net/10962/d1002015
- Description: This study explores representation and use of indigenous heritage constructs with a view to identifying implications thereof for the quality and relevance of heritage education practices in post colonial southern Africa. Framed within a critical hermeneutic research paradigm under-laboured by critical realist ontology, the study was conducted using a multiple case study research design. The data collection protocol was three-phased, starting with a process of contextual profiling, within which insights were gained into discourses shaping the constitution and orientation of heritage education practices at the Albany Museum in South Africa, the Great Zimbabwe Monument in Zimbabwe and the Supa Ngwao Museum in Botswana. The second phase of data collection entailed modelling workshops in which educators engaged in discussion around the status of heritage education in post apartheid South Africa. This highlighted, through modelled lessons, some of the tensions, challenges and implications for working with notions of social transformation and inclusivity in heritage education. The third phase of data collection involved in-depth interviews. Twelve purposively selected research participants were interviewed between 2010 and 2011. Data generated across the study was processed and subjected to different levels of critical discourse analysis. Besides noting how heritage education in post colonial southern Africa is poorly framed and under-researched, this study revealed that current forms of representing indigenous heritage constructs are influenced more by socio-political discourses than the need to protect and conserve local heritage resources. The study also noted that the observed heritage education practices are oriented more towards addressing issues related to marginalisation and alienation of indigenous cultures and practices, than enhancing learners’ agency to manage and utilise local heritage resources in a more sustainable ways. Based on these findings the study recommends re-positioning heritage education within the framework of Education for Sustainable Development (ESD). ESD acknowledges both issues of social justice and the dialectical interplay between nature and culture; as such, it may allow for representation and use of indigenous heritage constructs in ways that expand current political orientations to include sustainability as an additional objective of heritage education. Given that little research focusing on heritage education has been undertaken within southern Africa, the findings of this study provide a basis upon which future research may emerge.
- Full Text:
- Date Issued: 2013
- Authors: Zazu, Cryton
- Date: 2013
- Subjects: Albany Museum (Grahamstown, South Africa) Cultural property -- Conservation and restoration -- Research -- Africa, Southern Great Zimbabwe (Extinct city) Indigenous peoples -- Material culture -- Africa, Southern Anthropological museums and collections -- Management -- Research -- Africa, Southern Cultural property -- Management -- Research Ethnoscience -- Study and teaching -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1407 , http://hdl.handle.net/10962/d1002015
- Description: This study explores representation and use of indigenous heritage constructs with a view to identifying implications thereof for the quality and relevance of heritage education practices in post colonial southern Africa. Framed within a critical hermeneutic research paradigm under-laboured by critical realist ontology, the study was conducted using a multiple case study research design. The data collection protocol was three-phased, starting with a process of contextual profiling, within which insights were gained into discourses shaping the constitution and orientation of heritage education practices at the Albany Museum in South Africa, the Great Zimbabwe Monument in Zimbabwe and the Supa Ngwao Museum in Botswana. The second phase of data collection entailed modelling workshops in which educators engaged in discussion around the status of heritage education in post apartheid South Africa. This highlighted, through modelled lessons, some of the tensions, challenges and implications for working with notions of social transformation and inclusivity in heritage education. The third phase of data collection involved in-depth interviews. Twelve purposively selected research participants were interviewed between 2010 and 2011. Data generated across the study was processed and subjected to different levels of critical discourse analysis. Besides noting how heritage education in post colonial southern Africa is poorly framed and under-researched, this study revealed that current forms of representing indigenous heritage constructs are influenced more by socio-political discourses than the need to protect and conserve local heritage resources. The study also noted that the observed heritage education practices are oriented more towards addressing issues related to marginalisation and alienation of indigenous cultures and practices, than enhancing learners’ agency to manage and utilise local heritage resources in a more sustainable ways. Based on these findings the study recommends re-positioning heritage education within the framework of Education for Sustainable Development (ESD). ESD acknowledges both issues of social justice and the dialectical interplay between nature and culture; as such, it may allow for representation and use of indigenous heritage constructs in ways that expand current political orientations to include sustainability as an additional objective of heritage education. Given that little research focusing on heritage education has been undertaken within southern Africa, the findings of this study provide a basis upon which future research may emerge.
- Full Text:
- Date Issued: 2013
Environmental water quality management of glyphosate-based herbicides in South Africa
- Authors: Mensah, Paul Kojo
- Date: 2013
- Subjects: Water quality management -- South Africa Water quality management -- Environmental Aspects -- South Africa Herbicides -- Environmental aspects -- South Africa Herbicides -- Toxicology -- South Africa Water -- Glyphosate content -- South Africa Water -- Pollution -- South Africa Water quality -- Measurement -- South Africa Water -- Analysis -- South Africa Freshwater ecology -- South Africa Integrated water development -- South Africa Caridina -- Effect of pollution on -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6023 , http://hdl.handle.net/10962/d1001987
- Description: Although the use of pesticides is necessary to meet the socio-economic needs of many developing countries, especially in Africa, side effects of these bio-active chemicals have contributed to contaminating aquatic and terrestrial ecosystems. Environmental water quality degradation by pesticides interferes with ecosystem health and poses numerous risks to aquatic life. In South Africa, glyphosate-based herbicides are frequently used to control weeds and invading alien plants, but ultimately end up in freshwater ecosystems. However, there are no South African-based environmental water quality management strategies to regulate these bio-active chemicals. Therefore, this study sought to provide a sound scientific background for the environmental water quality management of glyphosate-based herbicides in South Africa, by conducting both laboratory and field investigations. In the laboratory investigations, aquatic ecotoxicological methods were used to evaluate responses of the freshwater aquatic shrimp Caridina nilotica exposed to Roundup® at different biological system scales, and the responses of multiple South African aquatic species exposed to Roundup® through species sensitivity distribution (SSD). In the field investigations, the effect of Kilo Max WSG on the physicochemical and biological conditions of three selected sites in the Swartkops River before and after a spray episode by Working for Water were evaluated through biomonitoring, using the South African Scoring System version 5 (SASS5) as a sampling protocol. Both Roundup® and Kilo Max WSG are glyphosate-based herbicides. All the data were subjected to relevant statistical analyses. Findings of this study revealed that Roundup® elicited responses at different biological system scales in C. nilotica, while SSD estimates were used to derive proposed water quality guidelines for glyphosate-based herbicides in South Africa. The biomonitoring revealed that using glyphosate-based herbicides to control water hyacinth within the Swartkops River had a negligible impact on the physicochemical and biological conditions. Based on these findings, a conceptual framework that can be used for the integrated environmental water quality management of glyphosate-based herbicides in South Africa was developed as part of integrated water resource management (IWRM). The combined data sets contribute to a sound scientific basis for the environmental water quality management of glyphosate-based herbicides in South Africa.
- Full Text:
- Date Issued: 2013
- Authors: Mensah, Paul Kojo
- Date: 2013
- Subjects: Water quality management -- South Africa Water quality management -- Environmental Aspects -- South Africa Herbicides -- Environmental aspects -- South Africa Herbicides -- Toxicology -- South Africa Water -- Glyphosate content -- South Africa Water -- Pollution -- South Africa Water quality -- Measurement -- South Africa Water -- Analysis -- South Africa Freshwater ecology -- South Africa Integrated water development -- South Africa Caridina -- Effect of pollution on -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6023 , http://hdl.handle.net/10962/d1001987
- Description: Although the use of pesticides is necessary to meet the socio-economic needs of many developing countries, especially in Africa, side effects of these bio-active chemicals have contributed to contaminating aquatic and terrestrial ecosystems. Environmental water quality degradation by pesticides interferes with ecosystem health and poses numerous risks to aquatic life. In South Africa, glyphosate-based herbicides are frequently used to control weeds and invading alien plants, but ultimately end up in freshwater ecosystems. However, there are no South African-based environmental water quality management strategies to regulate these bio-active chemicals. Therefore, this study sought to provide a sound scientific background for the environmental water quality management of glyphosate-based herbicides in South Africa, by conducting both laboratory and field investigations. In the laboratory investigations, aquatic ecotoxicological methods were used to evaluate responses of the freshwater aquatic shrimp Caridina nilotica exposed to Roundup® at different biological system scales, and the responses of multiple South African aquatic species exposed to Roundup® through species sensitivity distribution (SSD). In the field investigations, the effect of Kilo Max WSG on the physicochemical and biological conditions of three selected sites in the Swartkops River before and after a spray episode by Working for Water were evaluated through biomonitoring, using the South African Scoring System version 5 (SASS5) as a sampling protocol. Both Roundup® and Kilo Max WSG are glyphosate-based herbicides. All the data were subjected to relevant statistical analyses. Findings of this study revealed that Roundup® elicited responses at different biological system scales in C. nilotica, while SSD estimates were used to derive proposed water quality guidelines for glyphosate-based herbicides in South Africa. The biomonitoring revealed that using glyphosate-based herbicides to control water hyacinth within the Swartkops River had a negligible impact on the physicochemical and biological conditions. Based on these findings, a conceptual framework that can be used for the integrated environmental water quality management of glyphosate-based herbicides in South Africa was developed as part of integrated water resource management (IWRM). The combined data sets contribute to a sound scientific basis for the environmental water quality management of glyphosate-based herbicides in South Africa.
- Full Text:
- Date Issued: 2013
Afro-communitarianism and the nature of reconciliation
- Authors: Oelofsen, Rianna
- Date: 2013
- Subjects: Ubuntu (Philosophy) Reconciliation -- South Africa Communitarianism -- Africa Philosophy, African
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2736 , http://hdl.handle.net/10962/d1006809
- Description: In this dissertation I sketch a conception of personhood as understood from within an Afrocommunitarian worldview, and argue that this understanding of personhood has implications for understanding the concept of reconciliation. Understanding ‘being human’ as a collective, communal enterprise has implications for how responsibility, justice, forgiveness and humanization (all cognate concepts of reconciliation) are conceptualized. In line with this understanding of reconciliation and its cognate concepts, I argue that the humanization of self and other (according to the Afrocommunitarian understanding of personhood) is required for addressing the ‘inferiority’ and concurrent ‘superiority’ racial complexes as diagnosed by Franz Fanon and Steve Biko. These complexes reach deeply within individual and collective psyches and political identities, and I argue that political solutions to protracted conflict (in South Africa and other racially charged contexts) which do not address these deeply entrenched pathologies will be inadequate according to an Afrocommunitarian framework.
- Full Text:
- Date Issued: 2013
- Authors: Oelofsen, Rianna
- Date: 2013
- Subjects: Ubuntu (Philosophy) Reconciliation -- South Africa Communitarianism -- Africa Philosophy, African
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2736 , http://hdl.handle.net/10962/d1006809
- Description: In this dissertation I sketch a conception of personhood as understood from within an Afrocommunitarian worldview, and argue that this understanding of personhood has implications for understanding the concept of reconciliation. Understanding ‘being human’ as a collective, communal enterprise has implications for how responsibility, justice, forgiveness and humanization (all cognate concepts of reconciliation) are conceptualized. In line with this understanding of reconciliation and its cognate concepts, I argue that the humanization of self and other (according to the Afrocommunitarian understanding of personhood) is required for addressing the ‘inferiority’ and concurrent ‘superiority’ racial complexes as diagnosed by Franz Fanon and Steve Biko. These complexes reach deeply within individual and collective psyches and political identities, and I argue that political solutions to protracted conflict (in South Africa and other racially charged contexts) which do not address these deeply entrenched pathologies will be inadequate according to an Afrocommunitarian framework.
- Full Text:
- Date Issued: 2013
A social realist account of the tutorial system at the University of Johannesburg
- Authors: Layton, Delia Melanie
- Date: 2013
- Subjects: University of Johannesburg Education, Higher -- South Africa Tutors and tutoring -- South Africa College teaching -- South Africa Archer, Margaret Scotford College student development programs -- South Africa Social realism , Tutorial system
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1314 , http://hdl.handle.net/10962/d1001621
- Description: Using Margaret Archer’s social realist methodology, this study critically examines the construction of the tutorial system in several departments and faculties at the Auckland Park campus of the University of Johannesburg. The purpose of the study is to investigate the extent to which tutorials support the acquisition of programme and disciplinary epistemologies. Social realism calls for analytical dualism of ‘the people’ (agents) from ‘the parts’ (structure and culture). This requires the separate consideration of structures (social systems, rules, roles, practices, policies, institutions, and organisational structures like committees, units, departments, faculties), culture (ideologies, theories, beliefs and values as evidenced in discourses), and agency (people and their ability to act within and upon their own world in terms of their social roles and positions dependent on their ability to activate their emergent properties and powers). Through this investigation, an understanding was gained into how the emergent properties and powers contained within the material, ideational and agential elements helped to generate certain events and practices in the tutorial system. These generative mechanisms were examined to explore whether they enabled or constrained the construction of the tutorial system to provide epistemological access. The study shows that while many official policy documents construct the tutorial system as being an intervention to support academic success, particularly for first-years, there are some tensions within the document discourses, where, on the one hand, student success is constructed in terms of throughput numbers, or, on the other hand, as being about becoming a particular kind of person who is able to access and add to powerful knowledge. Furthermore, the study found that policies are not being consistently implemented. While certain key agents and actors, in the form of management, academics and tutors, were found to be able to overcome constraints and introduce innovative ways of enhancing access to target epistemologies, there is a need for consideration of structural and cultural constraints. For example, structures in the form of funding, venues and timetabling were found to constrain the tutorial system as did some of the discourses in the cultural domain: for example, in the form of certain dominant discourses around teaching and learning, beliefs about the purpose of the tutorial and the relationship between academics and the tutorial system. The study also found that the ontological aspects of ‘learning to be’ were not fore-grounded to any great extent in the ways in which the tutorial system was constructed. There needs to be more consideration of the ontological as well as the epistemological aspects of first-year study so as to take cognisance of the different learning needs of an increasingly diverse student body and to encourage the development of the student agency necessary for a deep engagement with the disciplinary epistemologies.
- Full Text:
- Date Issued: 2013
- Authors: Layton, Delia Melanie
- Date: 2013
- Subjects: University of Johannesburg Education, Higher -- South Africa Tutors and tutoring -- South Africa College teaching -- South Africa Archer, Margaret Scotford College student development programs -- South Africa Social realism , Tutorial system
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1314 , http://hdl.handle.net/10962/d1001621
- Description: Using Margaret Archer’s social realist methodology, this study critically examines the construction of the tutorial system in several departments and faculties at the Auckland Park campus of the University of Johannesburg. The purpose of the study is to investigate the extent to which tutorials support the acquisition of programme and disciplinary epistemologies. Social realism calls for analytical dualism of ‘the people’ (agents) from ‘the parts’ (structure and culture). This requires the separate consideration of structures (social systems, rules, roles, practices, policies, institutions, and organisational structures like committees, units, departments, faculties), culture (ideologies, theories, beliefs and values as evidenced in discourses), and agency (people and their ability to act within and upon their own world in terms of their social roles and positions dependent on their ability to activate their emergent properties and powers). Through this investigation, an understanding was gained into how the emergent properties and powers contained within the material, ideational and agential elements helped to generate certain events and practices in the tutorial system. These generative mechanisms were examined to explore whether they enabled or constrained the construction of the tutorial system to provide epistemological access. The study shows that while many official policy documents construct the tutorial system as being an intervention to support academic success, particularly for first-years, there are some tensions within the document discourses, where, on the one hand, student success is constructed in terms of throughput numbers, or, on the other hand, as being about becoming a particular kind of person who is able to access and add to powerful knowledge. Furthermore, the study found that policies are not being consistently implemented. While certain key agents and actors, in the form of management, academics and tutors, were found to be able to overcome constraints and introduce innovative ways of enhancing access to target epistemologies, there is a need for consideration of structural and cultural constraints. For example, structures in the form of funding, venues and timetabling were found to constrain the tutorial system as did some of the discourses in the cultural domain: for example, in the form of certain dominant discourses around teaching and learning, beliefs about the purpose of the tutorial and the relationship between academics and the tutorial system. The study also found that the ontological aspects of ‘learning to be’ were not fore-grounded to any great extent in the ways in which the tutorial system was constructed. There needs to be more consideration of the ontological as well as the epistemological aspects of first-year study so as to take cognisance of the different learning needs of an increasingly diverse student body and to encourage the development of the student agency necessary for a deep engagement with the disciplinary epistemologies.
- Full Text:
- Date Issued: 2013
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
Exploring and expanding capabilities, sustainability and gender justice in science teacher education : case studies in Zimbabwe and South Africa
- Authors: Chikunda, Charles
- Date: 2013 , 2013-08-30
- Subjects: Science teachers -- Training of -- South Africa -- Case studies Science teachers -- Training of -- Zimbabwe -- Case studies Mathematics teachers -- Training of -- South Africa -- Case studies Women in education -- South Africa -- Case studies Women in education -- Zimbabwe -- Case studies Environmental education -- Study and teaching -- Case studies Curriculum planning -- South Africa Curriculum planning -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1887 , http://hdl.handle.net/10962/d1006026
- Description: The focus of this study was to explore and expand capabilities, sustainability and gender justice in Science, Mathematics and Technical subjects (SMTs) in teacher education curriculum practices as a process of Education for Sustainable Development in two case studies in Zimbabwe and South Africa. The study begins by discussing gender and science education discourse, locating it within Education for Sustainable Development discourse. Through this nexus, the study was able to explore gender and sustainability responsiveness of the curriculum practices of teacher educators in Science, Mathematics and Technical subjects; scrutinise underlying mechanisms that affect (promote or constrain) gender and sustainability responsive curriculum practices; and understand if and how teacher education curriculum practices consider the functionings and capabilities of females in relation to increased socio-ecological risk in a Southern African context. Influenced by a curriculum transformation commitment, an expansive learning phase was conducted to promote gender and sustainability responsive pedagogies in teacher education curriculum practices. As shown in the study, the expansive learning processes resulted in (re)conceptualising the curriculum practices (object), analysis of contradictions and developing new ways of doing work. Drawing from the sensitising concepts of dialectics, reflexivity and agency, the study worked with the three theoretical approaches of Cultural Historical Activity Theory (CHAT), feminist theory and capabilities theory. The capability and feminist lenses were used in the exploration of gender and sustainability responsiveness in science teacher education curriculum practices. CHAT, through its associated methodology of Developmental Work Research, offered the opportunity for researcher and participants in this study to come together to question and analyse curriculum practices and model new ways of doing work. Case study research was used in two case studies of teacher education curriculum practices in Science, Mathematics and Technical subjects, one in Zimbabwe and one in South Africa. Each case study is constituted with a networked activity system. The study used in-depth and focus group interviews and document analysis to explore gender and sustainability responsiveness in curriculum practices and to generate mirror data. Inductive and abductive modes of inference, and Critical Discourse Analysis were used to analyse data. This data was then used in Change Laboratory Workshops, where double stimulation and focus group discussions contributed to the expansive learning process. Findings from the exploration phase of the study revealed that most teacher educators in the two case studies had some basic levels of gender sensitivity, meaning that they had ability to perceive existing gender inequalities as it applies only to gender disaggregated data especially when it comes to enrolment and retention. However, there was no institutionalised pedagogic device in place in both case studies aimed at equipping future teachers with knowledge, skills, attitudes and values to promote aspects of capabilities (well-being achievement, wellbeing freedom, agency achievement and agency freedom) for girls in Science, Mathematics and Technical subjects. Science, Mathematics and Technical subjects teacher educators' curriculum practices were gender neutral, but in a gendered environment. This was a pedagogical tension that was visible in both case studies. On the other hand, socio-ecological issues, in cases where they were incorporated into the curriculum, were incorporated in a gender blind or gender neutral manner. Social ecological concerns such as climate change were treated as if they were not gendered both in their impact and in their mitigation and adaptation. It emerged that causal mechanisms shaping this situation were of a socio-political nature: there exist cultural differences between students and teacher educators; patriarchal ideology and hegemony; as well as other interfering binaries such as race and class. Other curriculum related constraints, though embedded in the socio-cultural-political nexus, include: rigid and content heavy curriculum, coupled with students who come into the system with inadequate content knowledge; and philosophy informing pedagogy namely scientism, with associated instrumentalist and functionalist tenets. All these led to contradictions between pedagogical practices with those expected by the Education for Sustainable Development framework. The study contributes in-depth insight into science teacher education curriculum development. By locating the study at the nexus of gender and Science, Mathematics and Technical subjects within the Education for Sustainable Development discourse, using the ontological lenses of feminist and capabilities, it was possible to interrogate aspects of quality and relevance of the science teacher education curriculum. The study also provides insight into participatory research and learning processes especially within the context of policy and curriculum development. It provides empirical evidence of mobilising reflexivity amongst both policy makers and policy implementers towards building human agency in policy translation for a curriculum transformation that is critical for responding to contemporary socio-ecological risks. , Microsoft� Word 2010 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Chikunda, Charles
- Date: 2013 , 2013-08-30
- Subjects: Science teachers -- Training of -- South Africa -- Case studies Science teachers -- Training of -- Zimbabwe -- Case studies Mathematics teachers -- Training of -- South Africa -- Case studies Women in education -- South Africa -- Case studies Women in education -- Zimbabwe -- Case studies Environmental education -- Study and teaching -- Case studies Curriculum planning -- South Africa Curriculum planning -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1887 , http://hdl.handle.net/10962/d1006026
- Description: The focus of this study was to explore and expand capabilities, sustainability and gender justice in Science, Mathematics and Technical subjects (SMTs) in teacher education curriculum practices as a process of Education for Sustainable Development in two case studies in Zimbabwe and South Africa. The study begins by discussing gender and science education discourse, locating it within Education for Sustainable Development discourse. Through this nexus, the study was able to explore gender and sustainability responsiveness of the curriculum practices of teacher educators in Science, Mathematics and Technical subjects; scrutinise underlying mechanisms that affect (promote or constrain) gender and sustainability responsive curriculum practices; and understand if and how teacher education curriculum practices consider the functionings and capabilities of females in relation to increased socio-ecological risk in a Southern African context. Influenced by a curriculum transformation commitment, an expansive learning phase was conducted to promote gender and sustainability responsive pedagogies in teacher education curriculum practices. As shown in the study, the expansive learning processes resulted in (re)conceptualising the curriculum practices (object), analysis of contradictions and developing new ways of doing work. Drawing from the sensitising concepts of dialectics, reflexivity and agency, the study worked with the three theoretical approaches of Cultural Historical Activity Theory (CHAT), feminist theory and capabilities theory. The capability and feminist lenses were used in the exploration of gender and sustainability responsiveness in science teacher education curriculum practices. CHAT, through its associated methodology of Developmental Work Research, offered the opportunity for researcher and participants in this study to come together to question and analyse curriculum practices and model new ways of doing work. Case study research was used in two case studies of teacher education curriculum practices in Science, Mathematics and Technical subjects, one in Zimbabwe and one in South Africa. Each case study is constituted with a networked activity system. The study used in-depth and focus group interviews and document analysis to explore gender and sustainability responsiveness in curriculum practices and to generate mirror data. Inductive and abductive modes of inference, and Critical Discourse Analysis were used to analyse data. This data was then used in Change Laboratory Workshops, where double stimulation and focus group discussions contributed to the expansive learning process. Findings from the exploration phase of the study revealed that most teacher educators in the two case studies had some basic levels of gender sensitivity, meaning that they had ability to perceive existing gender inequalities as it applies only to gender disaggregated data especially when it comes to enrolment and retention. However, there was no institutionalised pedagogic device in place in both case studies aimed at equipping future teachers with knowledge, skills, attitudes and values to promote aspects of capabilities (well-being achievement, wellbeing freedom, agency achievement and agency freedom) for girls in Science, Mathematics and Technical subjects. Science, Mathematics and Technical subjects teacher educators' curriculum practices were gender neutral, but in a gendered environment. This was a pedagogical tension that was visible in both case studies. On the other hand, socio-ecological issues, in cases where they were incorporated into the curriculum, were incorporated in a gender blind or gender neutral manner. Social ecological concerns such as climate change were treated as if they were not gendered both in their impact and in their mitigation and adaptation. It emerged that causal mechanisms shaping this situation were of a socio-political nature: there exist cultural differences between students and teacher educators; patriarchal ideology and hegemony; as well as other interfering binaries such as race and class. Other curriculum related constraints, though embedded in the socio-cultural-political nexus, include: rigid and content heavy curriculum, coupled with students who come into the system with inadequate content knowledge; and philosophy informing pedagogy namely scientism, with associated instrumentalist and functionalist tenets. All these led to contradictions between pedagogical practices with those expected by the Education for Sustainable Development framework. The study contributes in-depth insight into science teacher education curriculum development. By locating the study at the nexus of gender and Science, Mathematics and Technical subjects within the Education for Sustainable Development discourse, using the ontological lenses of feminist and capabilities, it was possible to interrogate aspects of quality and relevance of the science teacher education curriculum. The study also provides insight into participatory research and learning processes especially within the context of policy and curriculum development. It provides empirical evidence of mobilising reflexivity amongst both policy makers and policy implementers towards building human agency in policy translation for a curriculum transformation that is critical for responding to contemporary socio-ecological risks. , Microsoft� Word 2010 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The ecology and management of the large carnivore guild on Shamwari Game Reserve, Eastern Cape
- Authors: O'Brien, John William
- Date: 2013
- Subjects: Cheetah -- Behavior -- South Africa -- Shamwari Game Reserve Shamwari Game Reserve (South Africa) Carnivora -- South Africa -- Shamwari Game Reserve Wildlife conservation -- South Africa -- Shamwari Game Reserve Game reserves -- Management -- South Africa -- Shamwari Game Reserve Lion -- Behavior -- South Africa -- Shamwari Game Reserve Lion -- Ecology -- South Africa -- Shamwari Game Reserve African wild dog -- Ecology -- South Africa -- Shamwari Game Reserve Cheetah -- Ecology -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Cheetah -- Food -- South Africa -- Shamwari Game Reserve African wild dog -- Behavior -- South Africa -- Shamwari Game Reserve African wild dog -- Food -- South Africa -- Shamwari Game Reserve Leopard -- Behavior -- South Africa -- Shamwari Game Reserve Leopard -- Ecology -- South Africa -- Shamwari Game Reserve Leopard -- Food --South Africa -- Shamwari Game Reserve
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5609 , http://hdl.handle.net/10962/d1002604
- Description: Shamwari Game Reserve was the first enclosed conservation area in the Eastern Cape Province of South Africa to reintroduce free ranging lions, cheetahs, leopards and wild dogs back into their historic range. At that time (2000 – 2001), little information was available on the ecology and behaviour of these predators in the habitats of the Eastern Cape, and management decisions were based on assumptions and unfounded comparisons with extant populations but from quite different habitats. The aim of this study was therefore to obtain a better understanding of the feeding ecology and space use of the predator guild, and the carrying capacity of Shamwari Game Reserve to enable more informed management decisions. In addition, the reserve is a photographic based tourism venture and understanding both the ecological and financial sustainability of the predator guild was important. The diets of the predators were similar to those reported in other studies; larger predators killed a greater range of prey species than did smaller predators and a small number of prey species made up the majority of the kills. The larger predators had a higher mean kill mass than the smaller species and prey selection was influenced by prey size, prey abundance and prey habitat preference, and risk associated with hunting the species. Diet was flexible and responded to natural and management induced changes in prey abundance. There was a considerable overlap in space use by the lions, cheetahs and leopards with their core areas being centred on and around the Bushmans River. Space use was driven by resource distribution and landscape attributes, and by the presence of other predators of the same or different species. The long term viability of wild dog within the reserve was explored and the results confirmed that there was neither the required space nor the ecological processes and the wild dogs were removed from the reserve. A carrying capacity of the reserve for the predator guild was determined using the Maximum Sustainable Yield method to assess the potential prey species off take and a resultant density of 3.3 to 6.6 lion female equivalent units per 10 000 ha was established. The natural carrying capacity of the reserve with respect to predators will not sustain the tourism objectives and consequently prey supplementation was necessary to maintain predator density at levels high enough to sustain tourism. Under these conditions the large predator guild is still sustainable financially although careful, responsible management is needed to provide ecological sustainability.
- Full Text:
- Date Issued: 2013
- Authors: O'Brien, John William
- Date: 2013
- Subjects: Cheetah -- Behavior -- South Africa -- Shamwari Game Reserve Shamwari Game Reserve (South Africa) Carnivora -- South Africa -- Shamwari Game Reserve Wildlife conservation -- South Africa -- Shamwari Game Reserve Game reserves -- Management -- South Africa -- Shamwari Game Reserve Lion -- Behavior -- South Africa -- Shamwari Game Reserve Lion -- Ecology -- South Africa -- Shamwari Game Reserve African wild dog -- Ecology -- South Africa -- Shamwari Game Reserve Cheetah -- Ecology -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Cheetah -- Food -- South Africa -- Shamwari Game Reserve African wild dog -- Behavior -- South Africa -- Shamwari Game Reserve African wild dog -- Food -- South Africa -- Shamwari Game Reserve Leopard -- Behavior -- South Africa -- Shamwari Game Reserve Leopard -- Ecology -- South Africa -- Shamwari Game Reserve Leopard -- Food --South Africa -- Shamwari Game Reserve
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5609 , http://hdl.handle.net/10962/d1002604
- Description: Shamwari Game Reserve was the first enclosed conservation area in the Eastern Cape Province of South Africa to reintroduce free ranging lions, cheetahs, leopards and wild dogs back into their historic range. At that time (2000 – 2001), little information was available on the ecology and behaviour of these predators in the habitats of the Eastern Cape, and management decisions were based on assumptions and unfounded comparisons with extant populations but from quite different habitats. The aim of this study was therefore to obtain a better understanding of the feeding ecology and space use of the predator guild, and the carrying capacity of Shamwari Game Reserve to enable more informed management decisions. In addition, the reserve is a photographic based tourism venture and understanding both the ecological and financial sustainability of the predator guild was important. The diets of the predators were similar to those reported in other studies; larger predators killed a greater range of prey species than did smaller predators and a small number of prey species made up the majority of the kills. The larger predators had a higher mean kill mass than the smaller species and prey selection was influenced by prey size, prey abundance and prey habitat preference, and risk associated with hunting the species. Diet was flexible and responded to natural and management induced changes in prey abundance. There was a considerable overlap in space use by the lions, cheetahs and leopards with their core areas being centred on and around the Bushmans River. Space use was driven by resource distribution and landscape attributes, and by the presence of other predators of the same or different species. The long term viability of wild dog within the reserve was explored and the results confirmed that there was neither the required space nor the ecological processes and the wild dogs were removed from the reserve. A carrying capacity of the reserve for the predator guild was determined using the Maximum Sustainable Yield method to assess the potential prey species off take and a resultant density of 3.3 to 6.6 lion female equivalent units per 10 000 ha was established. The natural carrying capacity of the reserve with respect to predators will not sustain the tourism objectives and consequently prey supplementation was necessary to maintain predator density at levels high enough to sustain tourism. Under these conditions the large predator guild is still sustainable financially although careful, responsible management is needed to provide ecological sustainability.
- Full Text:
- Date Issued: 2013
A critical realist exploration of the emergence, development, management and sustainability of a Christian private institution of higher education in Malawi
- Kadyakapita, Mozecie Spector John
- Authors: Kadyakapita, Mozecie Spector John
- Date: 2013 , 2013-03-24
- Subjects: Christian universities and colleges -- Administration -- Research -- Malawi Private universities and colleges -- Administration -- Research -- Malawi Education, Higher -- Administration -- Research -- Malawi Higher education and state -- Research -- Malawi Universities and colleges -- Malawi -- History Educational planning -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1400 , http://hdl.handle.net/10962/d1001818
- Description: This study was prompted by an interest in exploring ways in which the development of private higher education in Malawi could be more sustainable. It examines the challenges that private institutions of higher education face in different contexts and the underlying causes of these challenges. The aim of the study was to explore the emergence of private higher education (PHE) in Malawi, its management, development, the challenges it faces and the generative mechanisms of these challenges. The research is a case study of one of the earliest private institutions of higher education in Malawi. The institution is owned and operated by a Christian church organisation that has been operating a network of private primary and secondary schools and health centres since its establishment in Malawi in the early 1890s. Critical realism is used as an underlabourer for its stance on ontological, epistemological and ethical assumptions of reality and its views on agency and structure. Two theoretical frameworks - complexity theory and transformational leadership theories - are used as lenses to help make sense of the nature of social organisations and also as heuristic devices for organising and making sense of data. Data were collected using qualitative interviews, archival document content analysis and observation. Twenty participants were purposefully selected for interviews. The participants comprised a senior officer at the MoEST headquarters, proprietors, members of the top management team of the institution, administrative assistants, heads of academic and nonacademic departments, teachers and non-teaching staff and students. Abstracted data were analysed using inductive, abductive and retroductive modes of inference. The study established that the emergence of private higher education in Malawi was generated by a number of mechanisms. These include the need to survive the threat to socioeconomic development posed by global trends in scientific and technological issues that heavily rely on access to the knowledge economy; the need to respond to demand for equity and access to higher education; the need to carry out the mission of the Christian church; government’s failure to expand and widen access to higher education; and the agential need to survive economic demands. The research findings indicate that a critical challenge that the emergence of private higher education faced was the lack of adequate and efficient structures and systems in the Ministry of Education, Science and Technology to expeditiously process applications to establish and accredit, monitor and control the development of private higher education institutions. It was also found that the challenges that the private higher education faces include high level of authoritarian governance and management practices, weak institutional management and control systems and structure, secularisation, lack of adequate funds to meet operation and capital development costs, facilities and resources to support teaching – learning functions, learner support facilities and services and a critical shortage of appropriately qualified administrative and academic personnel. The underlying causes of the challenges include the perceived threat to personal power and survival; fear of apostasy and secularisation; cultural values, adverse socioeconomic conditions; lack of diverse sources of funding, ineffective communication skills; weak governance systems and structures; low level of self-control; unfavourable attitudes towards educational institutions and the need to restore equity. To make private institutions of higher learning more sustainable, the study recommends that governance practices be guided by clear structures, policies and guidelines in the interest of transparency and accountability. It also recommends that government works in close partnership with private providers, reviews unfair policies concerning government scholarships, subsidizes the cost of materials for instruction and infrastructure development, and provides technical assistance to prospective and active providers. Lastly, the study recommends that private providers form an association so as to share experiences and to collectively deal with issues of common interest and concern. , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Kadyakapita, Mozecie Spector John
- Date: 2013 , 2013-03-24
- Subjects: Christian universities and colleges -- Administration -- Research -- Malawi Private universities and colleges -- Administration -- Research -- Malawi Education, Higher -- Administration -- Research -- Malawi Higher education and state -- Research -- Malawi Universities and colleges -- Malawi -- History Educational planning -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1400 , http://hdl.handle.net/10962/d1001818
- Description: This study was prompted by an interest in exploring ways in which the development of private higher education in Malawi could be more sustainable. It examines the challenges that private institutions of higher education face in different contexts and the underlying causes of these challenges. The aim of the study was to explore the emergence of private higher education (PHE) in Malawi, its management, development, the challenges it faces and the generative mechanisms of these challenges. The research is a case study of one of the earliest private institutions of higher education in Malawi. The institution is owned and operated by a Christian church organisation that has been operating a network of private primary and secondary schools and health centres since its establishment in Malawi in the early 1890s. Critical realism is used as an underlabourer for its stance on ontological, epistemological and ethical assumptions of reality and its views on agency and structure. Two theoretical frameworks - complexity theory and transformational leadership theories - are used as lenses to help make sense of the nature of social organisations and also as heuristic devices for organising and making sense of data. Data were collected using qualitative interviews, archival document content analysis and observation. Twenty participants were purposefully selected for interviews. The participants comprised a senior officer at the MoEST headquarters, proprietors, members of the top management team of the institution, administrative assistants, heads of academic and nonacademic departments, teachers and non-teaching staff and students. Abstracted data were analysed using inductive, abductive and retroductive modes of inference. The study established that the emergence of private higher education in Malawi was generated by a number of mechanisms. These include the need to survive the threat to socioeconomic development posed by global trends in scientific and technological issues that heavily rely on access to the knowledge economy; the need to respond to demand for equity and access to higher education; the need to carry out the mission of the Christian church; government’s failure to expand and widen access to higher education; and the agential need to survive economic demands. The research findings indicate that a critical challenge that the emergence of private higher education faced was the lack of adequate and efficient structures and systems in the Ministry of Education, Science and Technology to expeditiously process applications to establish and accredit, monitor and control the development of private higher education institutions. It was also found that the challenges that the private higher education faces include high level of authoritarian governance and management practices, weak institutional management and control systems and structure, secularisation, lack of adequate funds to meet operation and capital development costs, facilities and resources to support teaching – learning functions, learner support facilities and services and a critical shortage of appropriately qualified administrative and academic personnel. The underlying causes of the challenges include the perceived threat to personal power and survival; fear of apostasy and secularisation; cultural values, adverse socioeconomic conditions; lack of diverse sources of funding, ineffective communication skills; weak governance systems and structures; low level of self-control; unfavourable attitudes towards educational institutions and the need to restore equity. To make private institutions of higher learning more sustainable, the study recommends that governance practices be guided by clear structures, policies and guidelines in the interest of transparency and accountability. It also recommends that government works in close partnership with private providers, reviews unfair policies concerning government scholarships, subsidizes the cost of materials for instruction and infrastructure development, and provides technical assistance to prospective and active providers. Lastly, the study recommends that private providers form an association so as to share experiences and to collectively deal with issues of common interest and concern. , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The SKA's the limit : on the nature of faint radio sources
- Authors: McAlpine, Kim
- Date: 2013 , 2012-09-14
- Subjects: Radio telescopes -- South Africa Radio astronomy -- South Africa Square Kilometer Array (Spacecraft)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5504 , http://hdl.handle.net/10962/d1007271
- Description: From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources. , TeX , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: McAlpine, Kim
- Date: 2013 , 2012-09-14
- Subjects: Radio telescopes -- South Africa Radio astronomy -- South Africa Square Kilometer Array (Spacecraft)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5504 , http://hdl.handle.net/10962/d1007271
- Description: From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources. , TeX , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
Climate variability and climate change in water resources management of the Zambezi River basin
- Authors: Tirivarombo, Sithabile
- Date: 2013
- Subjects: Water resources development -- Zambezi River Watershed Climatic changes -- Zambezi River Watershed Water-supply -- Zambezi River Watershed Water-supply -- Political aspects -- Africa, Southern Water rights -- Africa, Southern Water security -- Africa, Southern Rain and rainfall -- Africa, Southern Rainfall probabilities -- Africa, Southern Food security -- Africa, Southern Drought forecasting -- Africa, Southern Watersheds -- Africa, Southern Water supply -- Measurement -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6024 , http://hdl.handle.net/10962/d1002955
- Description: Water is recognised as a key driver for social and economic development in the Zambezi basin. The basin is riparian to eight southern African countries and the transboundary nature of the basin’s water resources can be viewed as an agent of cooperation between the basin countries. It is possible, however, that the same water resource can lead to conflicts between water users. The southern African Water Vision for ‘equitable and sustainable utilisation of water for social, environmental justice and economic benefits for the present and future generations’ calls for an integrated and efficient management of water resources within the basin. Ensuring water and food security in the Zambezi basin is, however, faced with challenges due to high variability in climate and the available water resources. Water resources are under continuous threat from pollution, increased population growth, development and urbanisation as well as global climate change. These factors increase the demand for freshwater resources and have resulted in water being one of the major driving forces for development. The basin is also vulnerable due to lack of adequate financial resources and appropriate water resources infrastructure to enable viable, equitable and sustainable distribution of the water resources. This is in addition to the fact that the basin’s economic mainstay and social well-being are largely dependent on rainfed agriculture. There is also competition among the different water users and this has the potential to generate conflicts, which further hinder the development of water resources in the basin. This thesis has focused on the Zambezi River basin emphasising climate variability and climate change. It is now considered common knowledge that the global climate is changing and that many of the impacts will be felt through water resources. If these predictions are correct then the Zambezi basin is most likely to suffer under such impacts since its economic mainstay is largely determined by the availability of rainfall. It is the belief of this study that in order to ascertain the impacts of climate change, there should be a basis against which this change is evaluated. If we do not know the historical patterns of variability it may be difficult to predict changes in the future climate and in the hydrological resources and it will certainly be difficult to develop appropriate management strategies. Reliable quantitative estimates of water availability are a prerequisite for successful water resource plans. However, such initiatives have been hindered by paucity in data especially in a basin where gauging networks are inadequate and some of them have deteriorated. This is further compounded by shortages in resources, both human and financial, to ensure adequate monitoring. To address the data problems, this study largely relied on global data sets and the CRU TS2.1 rainfall grids were used for a large part of this study. The study starts by assessing the historical variability of rainfall and streamflow in the Zambezi basin and the results are used to inform the prediction of change in the future. Various methods of assessing historical trends were employed and regional drought indices were generated and evaluated against the historical rainfall trends. The study clearly demonstrates that the basin has a high degree of temporal and spatial variability in rainfall and streamflow at inter-annual and multi-decadal scales. The Standardised Precipitation Index, a rainfall based drought index, is used to assess historical drought events in the basin and it is shown that most of the droughts that have occurred were influenced by climatic and hydrological variability. It is concluded, through the evaluation of agricultural maize yields, that the basin’s food security is mostly constrained by the availability of rainfall. Comparing the viability of using a rainfall based index to a soil moisture based index as an agricultural drought indicator, this study concluded that a soil moisture based index is a better indicator since all of the water balance components are considered in the generation of the index. This index presents the actual amount of water available for the plant unlike purely rainfall based indices, that do not account for other components of the water budget that cause water losses. A number of challenges were, however, faced in assessing the variability and historical drought conditions, mainly due to the fact that most parts of the Zambezi basin are ungauged and available data are sparse, short and not continuous (with missing gaps). Hydrological modelling is frequently used to bridge the data gap and to facilitate the quantification of a basin’s hydrology for both gauged and ungauged catchments. The trend has been to use various methods of regionalisation to transfer information from gauged basins, or from basins with adequate physical basin data, to ungauged basins. All this is done to ensure that water resources are accounted for and that the future can be well planned. A number of approaches leading to the evaluation of the basin’s hydrological response to future climate change scenarios are taken. The Pitman rainfall-runoff model has enjoyed wide use as a water resources estimation tool in southern Africa. The model has been calibrated for the Zambezi basin but it should be acknowledged that any hydrological modelling process is characterised by many uncertainties arising from limitations in input data and inherent model structural uncertainty. The calibration process is thus carried out in a manner that embraces some of the uncertainties. Initial ranges of parameter values (maximum and minimum) that incorporate the possible parameter uncertainties are assigned in relation to physical basin properties. These parameter sets are used as input to the uncertainty version of the model to generate behavioural parameter space which is then further modified through manual calibration. The use of parameter ranges initially guided by the basin physical properties generates streamflows that adequately represent the historically observed amounts. This study concludes that the uncertainty framework and the Pitman model perform quite well in the Zambezi basin. Based on assumptions of an intensifying hydrological cycle, climate changes are frequently expected to result in negative impacts on water resources. However, it is important that basin scale assessments are undertaken so that appropriate future management strategies can be developed. To assess the likely changes in the Zambezi basin, the calibrated Pitman model was forced with downscaled and bias corrected GCM data. Three GCMs were used for this study, namely; ECHAM, GFDL and IPSL. The general observation made in this study is that the near future (2046-2065) conditions of the Zambezi basin are expected to remain within the ranges of historically observed variability. The differences between the predictions for the three GCMs are an indication of the uncertainties in the future and it has not been possible to make any firm conclusions about directions of change. It is therefore recommended that future water resources management strategies account for historical patterns of variability, but also for increased uncertainty. Any management strategies that are able to satisfactorily deal with the large variability that is evident from the historical data should be robust enough to account for the near future patterns of water availability predicted by this study. However, the uncertainties in these predictions suggest that improved monitoring systems are required to provide additional data against which future model outputs can be assessed.
- Full Text:
- Date Issued: 2013
- Authors: Tirivarombo, Sithabile
- Date: 2013
- Subjects: Water resources development -- Zambezi River Watershed Climatic changes -- Zambezi River Watershed Water-supply -- Zambezi River Watershed Water-supply -- Political aspects -- Africa, Southern Water rights -- Africa, Southern Water security -- Africa, Southern Rain and rainfall -- Africa, Southern Rainfall probabilities -- Africa, Southern Food security -- Africa, Southern Drought forecasting -- Africa, Southern Watersheds -- Africa, Southern Water supply -- Measurement -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6024 , http://hdl.handle.net/10962/d1002955
- Description: Water is recognised as a key driver for social and economic development in the Zambezi basin. The basin is riparian to eight southern African countries and the transboundary nature of the basin’s water resources can be viewed as an agent of cooperation between the basin countries. It is possible, however, that the same water resource can lead to conflicts between water users. The southern African Water Vision for ‘equitable and sustainable utilisation of water for social, environmental justice and economic benefits for the present and future generations’ calls for an integrated and efficient management of water resources within the basin. Ensuring water and food security in the Zambezi basin is, however, faced with challenges due to high variability in climate and the available water resources. Water resources are under continuous threat from pollution, increased population growth, development and urbanisation as well as global climate change. These factors increase the demand for freshwater resources and have resulted in water being one of the major driving forces for development. The basin is also vulnerable due to lack of adequate financial resources and appropriate water resources infrastructure to enable viable, equitable and sustainable distribution of the water resources. This is in addition to the fact that the basin’s economic mainstay and social well-being are largely dependent on rainfed agriculture. There is also competition among the different water users and this has the potential to generate conflicts, which further hinder the development of water resources in the basin. This thesis has focused on the Zambezi River basin emphasising climate variability and climate change. It is now considered common knowledge that the global climate is changing and that many of the impacts will be felt through water resources. If these predictions are correct then the Zambezi basin is most likely to suffer under such impacts since its economic mainstay is largely determined by the availability of rainfall. It is the belief of this study that in order to ascertain the impacts of climate change, there should be a basis against which this change is evaluated. If we do not know the historical patterns of variability it may be difficult to predict changes in the future climate and in the hydrological resources and it will certainly be difficult to develop appropriate management strategies. Reliable quantitative estimates of water availability are a prerequisite for successful water resource plans. However, such initiatives have been hindered by paucity in data especially in a basin where gauging networks are inadequate and some of them have deteriorated. This is further compounded by shortages in resources, both human and financial, to ensure adequate monitoring. To address the data problems, this study largely relied on global data sets and the CRU TS2.1 rainfall grids were used for a large part of this study. The study starts by assessing the historical variability of rainfall and streamflow in the Zambezi basin and the results are used to inform the prediction of change in the future. Various methods of assessing historical trends were employed and regional drought indices were generated and evaluated against the historical rainfall trends. The study clearly demonstrates that the basin has a high degree of temporal and spatial variability in rainfall and streamflow at inter-annual and multi-decadal scales. The Standardised Precipitation Index, a rainfall based drought index, is used to assess historical drought events in the basin and it is shown that most of the droughts that have occurred were influenced by climatic and hydrological variability. It is concluded, through the evaluation of agricultural maize yields, that the basin’s food security is mostly constrained by the availability of rainfall. Comparing the viability of using a rainfall based index to a soil moisture based index as an agricultural drought indicator, this study concluded that a soil moisture based index is a better indicator since all of the water balance components are considered in the generation of the index. This index presents the actual amount of water available for the plant unlike purely rainfall based indices, that do not account for other components of the water budget that cause water losses. A number of challenges were, however, faced in assessing the variability and historical drought conditions, mainly due to the fact that most parts of the Zambezi basin are ungauged and available data are sparse, short and not continuous (with missing gaps). Hydrological modelling is frequently used to bridge the data gap and to facilitate the quantification of a basin’s hydrology for both gauged and ungauged catchments. The trend has been to use various methods of regionalisation to transfer information from gauged basins, or from basins with adequate physical basin data, to ungauged basins. All this is done to ensure that water resources are accounted for and that the future can be well planned. A number of approaches leading to the evaluation of the basin’s hydrological response to future climate change scenarios are taken. The Pitman rainfall-runoff model has enjoyed wide use as a water resources estimation tool in southern Africa. The model has been calibrated for the Zambezi basin but it should be acknowledged that any hydrological modelling process is characterised by many uncertainties arising from limitations in input data and inherent model structural uncertainty. The calibration process is thus carried out in a manner that embraces some of the uncertainties. Initial ranges of parameter values (maximum and minimum) that incorporate the possible parameter uncertainties are assigned in relation to physical basin properties. These parameter sets are used as input to the uncertainty version of the model to generate behavioural parameter space which is then further modified through manual calibration. The use of parameter ranges initially guided by the basin physical properties generates streamflows that adequately represent the historically observed amounts. This study concludes that the uncertainty framework and the Pitman model perform quite well in the Zambezi basin. Based on assumptions of an intensifying hydrological cycle, climate changes are frequently expected to result in negative impacts on water resources. However, it is important that basin scale assessments are undertaken so that appropriate future management strategies can be developed. To assess the likely changes in the Zambezi basin, the calibrated Pitman model was forced with downscaled and bias corrected GCM data. Three GCMs were used for this study, namely; ECHAM, GFDL and IPSL. The general observation made in this study is that the near future (2046-2065) conditions of the Zambezi basin are expected to remain within the ranges of historically observed variability. The differences between the predictions for the three GCMs are an indication of the uncertainties in the future and it has not been possible to make any firm conclusions about directions of change. It is therefore recommended that future water resources management strategies account for historical patterns of variability, but also for increased uncertainty. Any management strategies that are able to satisfactorily deal with the large variability that is evident from the historical data should be robust enough to account for the near future patterns of water availability predicted by this study. However, the uncertainties in these predictions suggest that improved monitoring systems are required to provide additional data against which future model outputs can be assessed.
- Full Text:
- Date Issued: 2013
International joint ventures and firm value: an empirical study of South African partner firms
- Mangwengwende, Tadiwanashe Mukudzeyi
- Authors: Mangwengwende, Tadiwanashe Mukudzeyi
- Date: 2013
- Subjects: Joint ventures Joint ventures -- South Africa Business enterprises -- Valuation International business enterprises
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1033 , http://hdl.handle.net/10962/d1004174
- Description: This study investigates international equity joint ventures (IJVs) and South African partner firm value creation at formation. In addition, it tests whether four contentious formation characteristics, namely, the geographical location of the IJV partner, the level of economic development in the IJV partner’s home country, the level of equity held by the South African firm and the industry of the South African firm, can explain when South African IJVs are value enhancing and when they are value diminishing. IJVs are a popular business mode and an important channel for infrastructure and skills investment in developing countries. However, despite their popularity and potential social benefits, these IJVs are predominantly created by the decisions of private firms to collaborate with foreign firms and governments. Consequently the preservation and development of the IJV investment channel is dependent on the encouragement of private firm IJV participation. It is at uncovering potential tools to encourage IJV participation by South African firms that IJV firm value creation becomes important because it stands as a motivator for South African firms’ involvement in IJVs. Existing literature on IJVs and partner firm value has presented conflicting evidence with support for the views that they are value enhancing, value diminishing or of no immediate consequence to their partners’ firm value. Consequently, previous research offers limited firm value support for IJVs. For South African firms considering joint ventures and national policy makers determined to promote IJVs there is a need for an investigation of South African partner IJV firm value effects. Moreover, it is also necessary to test potential explanatory variables that may help to explain when the IJVs are value enhancing and when they are not as this will inform IJV contract negotiations and how limited national government resources are used to promote IJVs. In order to assess firm value creation for South African firms this study performed event studies on IJV formation announcements from 1998 to 2011 using daily share returns from the Johannesburg Securities Exchange taking care to incorporate recent developments in the event study methodology. The study found that while the market responds to IJV announcements, its responses do not, on average, reflect that IJVs are firm value enhancing for their South African partners at formation. This stands in contrast to considerable empirical literature and IJV firm value creation theory. In addition, factoring in formation characteristics, argued to potentially help explain cases of value creation and destruction from IJVs, provided limited explanation for positive and negative wealth effectsfor South African firms entering IJVs. This result has important value for IJV participants, national economic policy makers and IJV researchers. For IJV participants and national policy makers, the results caution unfettered entry/support for IJVs and challenge the role of equity distribution in determining the value of the IJV to its partner firms. For IJV researchers, the results present new evidence questioning IJV firm value creation at formation and provide a potential explanation for the conflict in previous IJV research. The study makes four key contributions to the existing knowledge of IJV firm value creation. Firstly, it assesses IJV wealth effects for the hitherto untested South African IJVs. Secondly, in doing so it adds a new data set (South African IJVs) to the current IJV literature. Thirdly, in reviewing the literature on IJV firm value creation the study presents a disaggregated model of IJV firm value creation from which to develop IJV research and potentially solve the persistent conflict in empirical results on IJV partner wealth effects. Finally, it informs future South African IJV agreements by uncovering factors that influence and do not influence partner wealth effects for South African firms.
- Full Text:
- Date Issued: 2013
- Authors: Mangwengwende, Tadiwanashe Mukudzeyi
- Date: 2013
- Subjects: Joint ventures Joint ventures -- South Africa Business enterprises -- Valuation International business enterprises
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1033 , http://hdl.handle.net/10962/d1004174
- Description: This study investigates international equity joint ventures (IJVs) and South African partner firm value creation at formation. In addition, it tests whether four contentious formation characteristics, namely, the geographical location of the IJV partner, the level of economic development in the IJV partner’s home country, the level of equity held by the South African firm and the industry of the South African firm, can explain when South African IJVs are value enhancing and when they are value diminishing. IJVs are a popular business mode and an important channel for infrastructure and skills investment in developing countries. However, despite their popularity and potential social benefits, these IJVs are predominantly created by the decisions of private firms to collaborate with foreign firms and governments. Consequently the preservation and development of the IJV investment channel is dependent on the encouragement of private firm IJV participation. It is at uncovering potential tools to encourage IJV participation by South African firms that IJV firm value creation becomes important because it stands as a motivator for South African firms’ involvement in IJVs. Existing literature on IJVs and partner firm value has presented conflicting evidence with support for the views that they are value enhancing, value diminishing or of no immediate consequence to their partners’ firm value. Consequently, previous research offers limited firm value support for IJVs. For South African firms considering joint ventures and national policy makers determined to promote IJVs there is a need for an investigation of South African partner IJV firm value effects. Moreover, it is also necessary to test potential explanatory variables that may help to explain when the IJVs are value enhancing and when they are not as this will inform IJV contract negotiations and how limited national government resources are used to promote IJVs. In order to assess firm value creation for South African firms this study performed event studies on IJV formation announcements from 1998 to 2011 using daily share returns from the Johannesburg Securities Exchange taking care to incorporate recent developments in the event study methodology. The study found that while the market responds to IJV announcements, its responses do not, on average, reflect that IJVs are firm value enhancing for their South African partners at formation. This stands in contrast to considerable empirical literature and IJV firm value creation theory. In addition, factoring in formation characteristics, argued to potentially help explain cases of value creation and destruction from IJVs, provided limited explanation for positive and negative wealth effectsfor South African firms entering IJVs. This result has important value for IJV participants, national economic policy makers and IJV researchers. For IJV participants and national policy makers, the results caution unfettered entry/support for IJVs and challenge the role of equity distribution in determining the value of the IJV to its partner firms. For IJV researchers, the results present new evidence questioning IJV firm value creation at formation and provide a potential explanation for the conflict in previous IJV research. The study makes four key contributions to the existing knowledge of IJV firm value creation. Firstly, it assesses IJV wealth effects for the hitherto untested South African IJVs. Secondly, in doing so it adds a new data set (South African IJVs) to the current IJV literature. Thirdly, in reviewing the literature on IJV firm value creation the study presents a disaggregated model of IJV firm value creation from which to develop IJV research and potentially solve the persistent conflict in empirical results on IJV partner wealth effects. Finally, it informs future South African IJV agreements by uncovering factors that influence and do not influence partner wealth effects for South African firms.
- Full Text:
- Date Issued: 2013
Numerical relativity on cosmological past null cones
- Van der Walt, Petrus Johannes
- Authors: Van der Walt, Petrus Johannes
- Date: 2013
- Subjects: Cosmology Numerical calculations General relativity (Physics) -- Mathematics Einstein field equations Gravity Gravitational waves Horizon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5396 , http://hdl.handle.net/10962/d1002959
- Description: The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.
- Full Text:
- Date Issued: 2013
- Authors: Van der Walt, Petrus Johannes
- Date: 2013
- Subjects: Cosmology Numerical calculations General relativity (Physics) -- Mathematics Einstein field equations Gravity Gravitational waves Horizon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5396 , http://hdl.handle.net/10962/d1002959
- Description: The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.
- Full Text:
- Date Issued: 2013
The influence of overwash and breaching events on the spatial and temporal patterns in ichthyofauna community composition in a temporarily open/closed southern African estuary
- Authors: Tweddle, Gavin Paul
- Date: 2013
- Subjects: Estuarine fishes -- Africa, Southern Marine fishes -- Africa, Southern Fishes -- Breeding -- Africa, Southern Fishes -- Effect of habitat modification on -- Africa, Southern Fishes -- Spawning -- Africa, Southern Gobiidae -- Africa, Southern Estuaries -- Africa, Southern Estuarine ecology -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5610 , http://hdl.handle.net/10962/d1002957
- Description: This study assessed the importance of overwash and breaching events on the ichthyofaunal community structure in the medium-sized temporarily open/closed Mpekweni Estuary located on the southeast coastline of southern Africa. The fish in the littoral zone of the estuary were sampled using a 5m seine net while the channel region was sampled using two nets, a smaller meshed 30m seine net to target the estuarine spawning species and the juvenile estuarine-dependant marine spawners, and a larger meshed 50m seine net to target the larger marine and freshwater spawning species. Intensive monthly sampling over two years provided data on selected physico-chemical and biological parameters. During the two year sampling period from November 2005 to October 2007 the estuary breached in late July 2006 and remained open till the sandbar re-formed across the mouth in late December 2006. Thus, sampling encompassed three open/closed phases 1) initial closed period, 2) open period and 3) re-closed period after the berm was re-formed. The open period was divided into two phases 1) the out-flow phase and 2) the tidal phase. A total of 36 fish species representing 19 families were sampled using the various seine nets employed during the investigation. In the littoral zone, the estuarine spawners (Estuarine Utilisation Category, [EUC] I), mainly the Gobiidae, Glossogobius callidus, dominated the samples numerically and by biomass. The smaller estuarine spawning species sampled in the channel were numerically dominated by Gilchristella aestuaria in conjunction with two other EUC I species, Atherina breviceps and G. callidus. The estuarine-dependant marine spawners (EUC II), however, dominated the ichthyofaunal biomass of the channel. The abundance and biomass of the larger species targeted were dominated by estuarine-dependant marine spawning species (EUC II), principally Rhabdosargus holubi. During the closed periods of the estuary, total fish abundance and biomass displayed weak seasonal patterns. The breaching event and subsequent open period was associated with a decrease in the total abundances of fish in the littoral zone and channel of the estuary, reflecting the out-flow of estuarine biomass-rich water into the marine environment. The breaching event coincided with a shift in the community composition of the ichthyofauna, reflecting the recruitment of marine spawning species into the estuary. Numerical analysis identified two distinct spatial fish communities within the estuary, a community associated with the mouth region and one comprising the rest of the estuary. The absence of any further spatial patterns in the ichthyofaunal community structure within the Mpekweni Estuary appear to be ascribed to the virtual absence of horizontal patterns in physico-chemical and biological parameters recorded in the system. Cohort analyses were employed to determine possible recruitment events for selected estuarine and marine spawning species. The estuarine spawning species displayed continuous recruitment patterns throughout the study, which appeared to be unaffected by the breaching event. Conversely, the larger marine spawning species displayed multiple cohorts, indicating non-continuous recruitment. Subsequent retrospective analysis of cohorts for the different species identified summer recruitment peaks that coincided with the breaching event and open period. Minor recruitment of marine spawning species also occurred during overwash events. The recruitment of ichthyofauna into the estuary was quantified during three distinct hydrological events: overwash, out-flow phase immediately after breaching and tidal phase during the period when the mouth was open. Estimates of fish recruitment were highest during the outflow phase immediately after the estuary breached and declined as the estuary became tidally inundated with marine water. Although not as high as the outflow and tidal phases, recruitment was evident during overwash events. Results of the current study highlight the importance of both breaching and overwashing events in structuring the ichthyofaunal community composition in a medium-sized southern African temporarily open/closed estuary. These results are broadly in agreement with similar studies conducted both locally and in other regions of the world.
- Full Text:
- Date Issued: 2013
- Authors: Tweddle, Gavin Paul
- Date: 2013
- Subjects: Estuarine fishes -- Africa, Southern Marine fishes -- Africa, Southern Fishes -- Breeding -- Africa, Southern Fishes -- Effect of habitat modification on -- Africa, Southern Fishes -- Spawning -- Africa, Southern Gobiidae -- Africa, Southern Estuaries -- Africa, Southern Estuarine ecology -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5610 , http://hdl.handle.net/10962/d1002957
- Description: This study assessed the importance of overwash and breaching events on the ichthyofaunal community structure in the medium-sized temporarily open/closed Mpekweni Estuary located on the southeast coastline of southern Africa. The fish in the littoral zone of the estuary were sampled using a 5m seine net while the channel region was sampled using two nets, a smaller meshed 30m seine net to target the estuarine spawning species and the juvenile estuarine-dependant marine spawners, and a larger meshed 50m seine net to target the larger marine and freshwater spawning species. Intensive monthly sampling over two years provided data on selected physico-chemical and biological parameters. During the two year sampling period from November 2005 to October 2007 the estuary breached in late July 2006 and remained open till the sandbar re-formed across the mouth in late December 2006. Thus, sampling encompassed three open/closed phases 1) initial closed period, 2) open period and 3) re-closed period after the berm was re-formed. The open period was divided into two phases 1) the out-flow phase and 2) the tidal phase. A total of 36 fish species representing 19 families were sampled using the various seine nets employed during the investigation. In the littoral zone, the estuarine spawners (Estuarine Utilisation Category, [EUC] I), mainly the Gobiidae, Glossogobius callidus, dominated the samples numerically and by biomass. The smaller estuarine spawning species sampled in the channel were numerically dominated by Gilchristella aestuaria in conjunction with two other EUC I species, Atherina breviceps and G. callidus. The estuarine-dependant marine spawners (EUC II), however, dominated the ichthyofaunal biomass of the channel. The abundance and biomass of the larger species targeted were dominated by estuarine-dependant marine spawning species (EUC II), principally Rhabdosargus holubi. During the closed periods of the estuary, total fish abundance and biomass displayed weak seasonal patterns. The breaching event and subsequent open period was associated with a decrease in the total abundances of fish in the littoral zone and channel of the estuary, reflecting the out-flow of estuarine biomass-rich water into the marine environment. The breaching event coincided with a shift in the community composition of the ichthyofauna, reflecting the recruitment of marine spawning species into the estuary. Numerical analysis identified two distinct spatial fish communities within the estuary, a community associated with the mouth region and one comprising the rest of the estuary. The absence of any further spatial patterns in the ichthyofaunal community structure within the Mpekweni Estuary appear to be ascribed to the virtual absence of horizontal patterns in physico-chemical and biological parameters recorded in the system. Cohort analyses were employed to determine possible recruitment events for selected estuarine and marine spawning species. The estuarine spawning species displayed continuous recruitment patterns throughout the study, which appeared to be unaffected by the breaching event. Conversely, the larger marine spawning species displayed multiple cohorts, indicating non-continuous recruitment. Subsequent retrospective analysis of cohorts for the different species identified summer recruitment peaks that coincided with the breaching event and open period. Minor recruitment of marine spawning species also occurred during overwash events. The recruitment of ichthyofauna into the estuary was quantified during three distinct hydrological events: overwash, out-flow phase immediately after breaching and tidal phase during the period when the mouth was open. Estimates of fish recruitment were highest during the outflow phase immediately after the estuary breached and declined as the estuary became tidally inundated with marine water. Although not as high as the outflow and tidal phases, recruitment was evident during overwash events. Results of the current study highlight the importance of both breaching and overwashing events in structuring the ichthyofaunal community composition in a medium-sized southern African temporarily open/closed estuary. These results are broadly in agreement with similar studies conducted both locally and in other regions of the world.
- Full Text:
- Date Issued: 2013
An investigation into how journalists experience economic and political pressures on their ethical decisions at the Nation Media Group in Kenya
- Authors: Maweu, Jacinta Mwende
- Date: 2013
- Subjects: Nation Media Group Limited Journalists -- Kenya Journalistic ethics -- Kenya Press and politics -- Kenya Journalism -- Economic aspects -- Kenya Journalism -- Political aspects -- Kenya Mass media -- Political aspects -- Kenya Mass media -- Economic aspects -- Kenya Freedom of the press -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3508 , http://hdl.handle.net/10962/d1007583
- Description: This study investigates how journalists experience economic and political pressures on their ethical decisions at the Nation Media Group (NMG) conglomerate in Kenya. The study uses qualitative semi- structured interviews to examine how journalists experience these pressures on their professional ethics as they make their daily decisions. Grounded in the critical political economy of the media tradition, the findings of the study indicate that economic and political pressures from advertisers, shareholders’ interests, the profit motive and the highly ethnicised political environment in Kenya largely compromise the ethical decisions of journalists. The study draws on the work done by Herman and Chomsky in their ‘Propaganda Model’ in which they propose ‘filters’ as the analytical indicators of the forms that political and economic pressures that journalists experience may take. The study explores the ways in which journalists experience these pressures, how they respond to the pressures and the ways in which their responses may compromise their journalism ethics. The findings indicate that aside from the pressures from the primary five filters outlined in the Propaganda Model, ethnicity in Kenyan newsrooms is a key ‘filter’ that may compromise the ethical decisions of journalists at the NMG. The study therefore argues that there is a need to modify the explanatory power of the Propaganda Model when applying it to the Kenyan context to include ethnicity as a ‘sixth filter’ that should be understood in relation to the five primary filters. From the findings, it would seem that the government is no longer a major threat to journalists’ freedom and responsibility in Kenya. Market forces and ethnicity in newsrooms pose the greatest threat to journalists’ freedom and responsibility. The study therefore calls for a revision of the normative framework within which journalists’ and media performance in Kenya is assessed. As the study findings show, the prevailing liberal- democratic model ignores the commercial and economic threats the ‘free market’ poses to journalism ethics as well as ethnicity in newsrooms and only focuses on the media- government relations, treating the government as the major threat to media freedom.
- Full Text:
- Date Issued: 2013
- Authors: Maweu, Jacinta Mwende
- Date: 2013
- Subjects: Nation Media Group Limited Journalists -- Kenya Journalistic ethics -- Kenya Press and politics -- Kenya Journalism -- Economic aspects -- Kenya Journalism -- Political aspects -- Kenya Mass media -- Political aspects -- Kenya Mass media -- Economic aspects -- Kenya Freedom of the press -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3508 , http://hdl.handle.net/10962/d1007583
- Description: This study investigates how journalists experience economic and political pressures on their ethical decisions at the Nation Media Group (NMG) conglomerate in Kenya. The study uses qualitative semi- structured interviews to examine how journalists experience these pressures on their professional ethics as they make their daily decisions. Grounded in the critical political economy of the media tradition, the findings of the study indicate that economic and political pressures from advertisers, shareholders’ interests, the profit motive and the highly ethnicised political environment in Kenya largely compromise the ethical decisions of journalists. The study draws on the work done by Herman and Chomsky in their ‘Propaganda Model’ in which they propose ‘filters’ as the analytical indicators of the forms that political and economic pressures that journalists experience may take. The study explores the ways in which journalists experience these pressures, how they respond to the pressures and the ways in which their responses may compromise their journalism ethics. The findings indicate that aside from the pressures from the primary five filters outlined in the Propaganda Model, ethnicity in Kenyan newsrooms is a key ‘filter’ that may compromise the ethical decisions of journalists at the NMG. The study therefore argues that there is a need to modify the explanatory power of the Propaganda Model when applying it to the Kenyan context to include ethnicity as a ‘sixth filter’ that should be understood in relation to the five primary filters. From the findings, it would seem that the government is no longer a major threat to journalists’ freedom and responsibility in Kenya. Market forces and ethnicity in newsrooms pose the greatest threat to journalists’ freedom and responsibility. The study therefore calls for a revision of the normative framework within which journalists’ and media performance in Kenya is assessed. As the study findings show, the prevailing liberal- democratic model ignores the commercial and economic threats the ‘free market’ poses to journalism ethics as well as ethnicity in newsrooms and only focuses on the media- government relations, treating the government as the major threat to media freedom.
- Full Text:
- Date Issued: 2013
Fixed points of single-valued and multi-valued mappings with applications
- Authors: Stofile, Simfumene
- Date: 2013
- Subjects: Fixed point theory Mappings (Mathematics) Coincidence theory (Mathematics) Metric spaces Uniform spaces Set-valued maps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5397 , http://hdl.handle.net/10962/d1002960
- Description: The relationship between the convergence of a sequence of self mappings of a metric space and their fixed points, known as the stability (or continuity) of fixed points has been of continuing interest and widely studied in fixed point theory. In this thesis we study the stability of common fixed points in a Hausdorff uniform space whose uniformity is generated by a family of pseudometrics, by using some general notations of convergence. These results are then extended to 2-metric spaces due to S. Gähler. In addition, a well-known theorem of T. Suzuki that generalized the Banach Contraction Principle is also extended to 2-metric spaces and applied to obtain a coincidence theorem for a pair of mappings on an arbitrary set with values in a 2-metric space. Further, we prove the existence of coincidence and fixed points of Ćirić type weakly generalized contractions in metric spaces. Subsequently, the above result is utilized to discuss applications to the convergence of modified Mann and Ishikawa iterations in a convex metric space. Finally, we obtain coincidence, fixed and stationary point results for multi-valued and hybrid pairs of mappings on a metric space.
- Full Text:
- Date Issued: 2013
- Authors: Stofile, Simfumene
- Date: 2013
- Subjects: Fixed point theory Mappings (Mathematics) Coincidence theory (Mathematics) Metric spaces Uniform spaces Set-valued maps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5397 , http://hdl.handle.net/10962/d1002960
- Description: The relationship between the convergence of a sequence of self mappings of a metric space and their fixed points, known as the stability (or continuity) of fixed points has been of continuing interest and widely studied in fixed point theory. In this thesis we study the stability of common fixed points in a Hausdorff uniform space whose uniformity is generated by a family of pseudometrics, by using some general notations of convergence. These results are then extended to 2-metric spaces due to S. Gähler. In addition, a well-known theorem of T. Suzuki that generalized the Banach Contraction Principle is also extended to 2-metric spaces and applied to obtain a coincidence theorem for a pair of mappings on an arbitrary set with values in a 2-metric space. Further, we prove the existence of coincidence and fixed points of Ćirić type weakly generalized contractions in metric spaces. Subsequently, the above result is utilized to discuss applications to the convergence of modified Mann and Ishikawa iterations in a convex metric space. Finally, we obtain coincidence, fixed and stationary point results for multi-valued and hybrid pairs of mappings on a metric space.
- Full Text:
- Date Issued: 2013
Drivers of macrophyte assemblages in South African freshwater systems
- Authors: Martin, Grant Douglas
- Date: 2013
- Subjects: Freshwater plants -- South Africa Aquatic weeds -- South Africa Invasive plants -- South Africa Freshwater ecology -- South Africa Biotic communities -- South Africa Maximum entropy method Lagarosiphon major -- South Africa Phytophagous insects -- South Africa Hydrellia -- South Africa Parasitoids -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5621 , http://hdl.handle.net/10962/d1004127
- Description: Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L. (Haloragaceae), and Cabomba caroliniana Gray (Cabombaceae). Despite the high probability of invasion, facilitated by vectors and suitable climate, South Africa’s rich indigenous submerged aquatic flora may be preventing the establishment of these submerged invasive species. Studies on the competitive interactions between a common indigenous submerged macrophytes, Lagarosiphon major (Roxb.) (Hydrocharitaceae) and M.spicatum, an invasive native to Eurasia, were conducted to ascertain which conditions influence competitive superiority. High sediment nutrient conditions significantly increased the growth rate and competitive ability of both species, while clay sediments significantly increased the competitive ability of L. major over M. spicatum, but sandy sediments improved the competitive ability of M. spicatum. These results highlighted the dynamic changes in competition between submerged species driven by abiotic factors, but did not take into consideration the effect that herbivory, a biotic factor, could have on competition between the two species. The effect of herbivory by phytophagous insects of submerged plant species has been regarded as negligible. To find out what this effect is, multiple field surveys were undertaken throughout South Africa to find natural enemies of indigenous Lagarosiphon species with the aim of identifying such species, and quantifying their influence on plant growth dynamics. Several new phytophagous species were recorded for the first time. An ephydrid fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae) was ascertained to be the most ubiquitous and abundant species associated with L. major in South Africa. The influence of herbivory by this fly on the competitive ability of L. major in the presence of M. spicatum was investigated using an inverse linear model, which showed that herbivory by H. lagarosiphon reduced the competitive ability of L. major by approximately five times in favour of M. spicatum. This study served to highlight the importance of herbivory as a driver of submerged aquatic plant dynamics. Current ecological theory emphasises the importance of investigating beyond plant-herbivore interactions, by including multitrophic interactions in community dynamics. Therefore, the potential of parasitism by a parasitoid wasp, Chaenusa luteostigma sp. n. Achterberg (Hymenoptera: Braconidae: Alysiinae) on H. lagarosiphon to shift the competitive interactions between the two plant species was also examined. The addition of the parasitoid reduced the effect of herbivory by the fly on L. major by half, thereby shifting the competitive balance in favour of L. major over M. spicatum. This study provides valuable insight into a selection of drivers of submerged macrophyte assemblages of South Africa. It highlights the precarious position of South African freshwater systems with regard to the potential invasion by damaging submerged invasive species. It also provides interesting insights into the effect of competition, herbivory and parasitism on the establishment and spread of species within submerged freshwater systems. Understanding the different influences could assist managers and policy makers to make validated decisions ensuring the integrity of South African freshwater systems.
- Full Text:
- Date Issued: 2013
- Authors: Martin, Grant Douglas
- Date: 2013
- Subjects: Freshwater plants -- South Africa Aquatic weeds -- South Africa Invasive plants -- South Africa Freshwater ecology -- South Africa Biotic communities -- South Africa Maximum entropy method Lagarosiphon major -- South Africa Phytophagous insects -- South Africa Hydrellia -- South Africa Parasitoids -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5621 , http://hdl.handle.net/10962/d1004127
- Description: Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L. (Haloragaceae), and Cabomba caroliniana Gray (Cabombaceae). Despite the high probability of invasion, facilitated by vectors and suitable climate, South Africa’s rich indigenous submerged aquatic flora may be preventing the establishment of these submerged invasive species. Studies on the competitive interactions between a common indigenous submerged macrophytes, Lagarosiphon major (Roxb.) (Hydrocharitaceae) and M.spicatum, an invasive native to Eurasia, were conducted to ascertain which conditions influence competitive superiority. High sediment nutrient conditions significantly increased the growth rate and competitive ability of both species, while clay sediments significantly increased the competitive ability of L. major over M. spicatum, but sandy sediments improved the competitive ability of M. spicatum. These results highlighted the dynamic changes in competition between submerged species driven by abiotic factors, but did not take into consideration the effect that herbivory, a biotic factor, could have on competition between the two species. The effect of herbivory by phytophagous insects of submerged plant species has been regarded as negligible. To find out what this effect is, multiple field surveys were undertaken throughout South Africa to find natural enemies of indigenous Lagarosiphon species with the aim of identifying such species, and quantifying their influence on plant growth dynamics. Several new phytophagous species were recorded for the first time. An ephydrid fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae) was ascertained to be the most ubiquitous and abundant species associated with L. major in South Africa. The influence of herbivory by this fly on the competitive ability of L. major in the presence of M. spicatum was investigated using an inverse linear model, which showed that herbivory by H. lagarosiphon reduced the competitive ability of L. major by approximately five times in favour of M. spicatum. This study served to highlight the importance of herbivory as a driver of submerged aquatic plant dynamics. Current ecological theory emphasises the importance of investigating beyond plant-herbivore interactions, by including multitrophic interactions in community dynamics. Therefore, the potential of parasitism by a parasitoid wasp, Chaenusa luteostigma sp. n. Achterberg (Hymenoptera: Braconidae: Alysiinae) on H. lagarosiphon to shift the competitive interactions between the two plant species was also examined. The addition of the parasitoid reduced the effect of herbivory by the fly on L. major by half, thereby shifting the competitive balance in favour of L. major over M. spicatum. This study provides valuable insight into a selection of drivers of submerged macrophyte assemblages of South Africa. It highlights the precarious position of South African freshwater systems with regard to the potential invasion by damaging submerged invasive species. It also provides interesting insights into the effect of competition, herbivory and parasitism on the establishment and spread of species within submerged freshwater systems. Understanding the different influences could assist managers and policy makers to make validated decisions ensuring the integrity of South African freshwater systems.
- Full Text:
- Date Issued: 2013
Positions on the mat : a micro-ethnographic study of teachers' and learners' co-construction of an early literacy practice
- Authors: Van der Mescht, Caroline
- Date: 2013 , 2013-06-10
- Subjects: Literacy -- Study and teaching (Primary) -- South Africa -- Eastern Cape English language -- Study and teaching (Primary) -- South Africa -- Eastern Cape English literature -- Study and teaching (Primary) -- South Africa -- Eastern Cape Education, Primary -- Research -- South Africa -- Eastern Cape Teachers -- Psychology Language and culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1836 , http://hdl.handle.net/10962/d1004333
- Description: Thesis embargoed until end of 2023. , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Van der Mescht, Caroline
- Date: 2013 , 2013-06-10
- Subjects: Literacy -- Study and teaching (Primary) -- South Africa -- Eastern Cape English language -- Study and teaching (Primary) -- South Africa -- Eastern Cape English literature -- Study and teaching (Primary) -- South Africa -- Eastern Cape Education, Primary -- Research -- South Africa -- Eastern Cape Teachers -- Psychology Language and culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1836 , http://hdl.handle.net/10962/d1004333
- Description: Thesis embargoed until end of 2023. , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
An investigation into the representations of environmental issues relating to Lake Victoria, Uganda, and their negotiation by the lakeside communities
- Lwanga, Margaret Jjuuko Nassuna
- Authors: Lwanga, Margaret Jjuuko Nassuna
- Date: 2013
- Subjects: Victoria Voice Victoria, Lake -- Environmental aspects -- Research Lakes -- Environmental aspects -- Research -- Uganda Environmental management -- Research -- Uganda Pollution -- Environmental aspects -- Uganda Radio broadcasting -- Uganda , Uganda CBS , Central Broadcasting Service , Mass media -- Environmental aspects -- Research -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3411 , http://hdl.handle.net/10962/d1001577
- Description: The state of the environment is increasingly present as an urgent concern for contemporary political, social, cultural and physical life. Yet the roles of the mass media (radio, television and newspapers) in shaping and influencing crucial public awareness, debates and environmental decision-making remain inadequately understood. Positioned as a critical studies inquiry into media representations and audience reception, this study forms part of a wider project amongst media scholars and culture critics on the relationship between media textual production and consumption. It explores how one radio station in Uganda, Central Broadcasting Service (CBS) radio, represents and constructs the environmental crises faced by Lake Victoria, especially pollution and overfishing. The focus is on the Victoria Voice radio documentaries aired on CBS radio in the year 2005. The study further explores how three lakeside communities negotiate these issues as radio broadcasts. It recognises that while the mass media contribute significantly to creating public awareness about such social concerns, their likelihood of having a direct and predictable impact on social behaviour is slight. The context and the lived experiences at the reception stage where the decisions are made on whether to adopt an innovation are ultimately the factors which impact on how they are negotiated. The thesis is informed by the theoretical and analytical framework of Cultural Studies as well as the Participatory Approach to Communication for Development perspectives. The study is specifically informed by the theories of ‘discourse’ (Foucault, 1980a, 1981) and the ‘circuit of culture’ (du Gay et al., 1997 and Johnson, 1987) and these provided the conceptual framework for investigating the representations, the production and the consumption of media texts. Predominantly qualitative methods have been employed in data collection and analysis. In the first place, a Critical Discourse Analysis (CDA) (Fairclough, 1995a, 1995c) of the radio texts has interrogated the discourses and discursive practices of CBS’ Victoria Voice environmental radio programmes in order to consider its representations of particular issues and consequently the discourses it privileged. Qualitative methods of participant observation, in-depth interviews and focus group discussions were deployed to investigate the negotiation of the texts by the lakeside communities. This research establishes that the Victoria Voice radio texts foreground three contesting types of discourses: the discourse of basic economic survival and livelihoods is articulated largely by the ordinary people, the lakeside communities; the discourse of sustainable development, particularly the protection and sustainability of Lake Victoria, by scientists and environmental experts; and the discourse of modernisation and corporate investment by politicians and/or policy makers and industrialists. The texts, to a large degree, reaffirm the hegemonic relations of power in Ugandan society, and thus contribute to the maintenance of the status quo. The selection of an elite category of informers (scientists, experts, politicians, policy makers) serves to marginalise the less powerful ordinary people (the fisher folk, farmers and other eyewitnesses). The construction of the elite as active and speaking subjects within the various debates introduced in these programmes, for example, works both to obscure and endorse the unequal power relations. At the reception side, while the lakeside communities attest to the relevance of the programmes in providing information on the issues concerning Lake Victoria and other aspects of their livelihood, they also recognise the power relations that underpin the sets of representations. Amongst these sets is government’s complicity with industry, in line with their economic policies and the global capitalist economy, while espousing the rhetoric of nature conservation. The study argues that sustainable solutions for the crises on Lake Victoria should take into account the socio-historical and cultural contexts of the lakeside communities. For the Ugandan media, particularly radio, there is a need to rethink the nature of the coverage, which tends to neglect the contextual factors, such as local socio-economic and cultural factors within which environmental issues and problems occur and which, as this thesis establishes, greatly influences the way people make sense of environmental issues and problems. I posit that the Participatory Approach that seeks to address the communities’ most pressing concerns should be adopted – to include more of the communities’ voices and involve them in the production of radio programmes.
- Full Text:
- Date Issued: 2013
- Authors: Lwanga, Margaret Jjuuko Nassuna
- Date: 2013
- Subjects: Victoria Voice Victoria, Lake -- Environmental aspects -- Research Lakes -- Environmental aspects -- Research -- Uganda Environmental management -- Research -- Uganda Pollution -- Environmental aspects -- Uganda Radio broadcasting -- Uganda , Uganda CBS , Central Broadcasting Service , Mass media -- Environmental aspects -- Research -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3411 , http://hdl.handle.net/10962/d1001577
- Description: The state of the environment is increasingly present as an urgent concern for contemporary political, social, cultural and physical life. Yet the roles of the mass media (radio, television and newspapers) in shaping and influencing crucial public awareness, debates and environmental decision-making remain inadequately understood. Positioned as a critical studies inquiry into media representations and audience reception, this study forms part of a wider project amongst media scholars and culture critics on the relationship between media textual production and consumption. It explores how one radio station in Uganda, Central Broadcasting Service (CBS) radio, represents and constructs the environmental crises faced by Lake Victoria, especially pollution and overfishing. The focus is on the Victoria Voice radio documentaries aired on CBS radio in the year 2005. The study further explores how three lakeside communities negotiate these issues as radio broadcasts. It recognises that while the mass media contribute significantly to creating public awareness about such social concerns, their likelihood of having a direct and predictable impact on social behaviour is slight. The context and the lived experiences at the reception stage where the decisions are made on whether to adopt an innovation are ultimately the factors which impact on how they are negotiated. The thesis is informed by the theoretical and analytical framework of Cultural Studies as well as the Participatory Approach to Communication for Development perspectives. The study is specifically informed by the theories of ‘discourse’ (Foucault, 1980a, 1981) and the ‘circuit of culture’ (du Gay et al., 1997 and Johnson, 1987) and these provided the conceptual framework for investigating the representations, the production and the consumption of media texts. Predominantly qualitative methods have been employed in data collection and analysis. In the first place, a Critical Discourse Analysis (CDA) (Fairclough, 1995a, 1995c) of the radio texts has interrogated the discourses and discursive practices of CBS’ Victoria Voice environmental radio programmes in order to consider its representations of particular issues and consequently the discourses it privileged. Qualitative methods of participant observation, in-depth interviews and focus group discussions were deployed to investigate the negotiation of the texts by the lakeside communities. This research establishes that the Victoria Voice radio texts foreground three contesting types of discourses: the discourse of basic economic survival and livelihoods is articulated largely by the ordinary people, the lakeside communities; the discourse of sustainable development, particularly the protection and sustainability of Lake Victoria, by scientists and environmental experts; and the discourse of modernisation and corporate investment by politicians and/or policy makers and industrialists. The texts, to a large degree, reaffirm the hegemonic relations of power in Ugandan society, and thus contribute to the maintenance of the status quo. The selection of an elite category of informers (scientists, experts, politicians, policy makers) serves to marginalise the less powerful ordinary people (the fisher folk, farmers and other eyewitnesses). The construction of the elite as active and speaking subjects within the various debates introduced in these programmes, for example, works both to obscure and endorse the unequal power relations. At the reception side, while the lakeside communities attest to the relevance of the programmes in providing information on the issues concerning Lake Victoria and other aspects of their livelihood, they also recognise the power relations that underpin the sets of representations. Amongst these sets is government’s complicity with industry, in line with their economic policies and the global capitalist economy, while espousing the rhetoric of nature conservation. The study argues that sustainable solutions for the crises on Lake Victoria should take into account the socio-historical and cultural contexts of the lakeside communities. For the Ugandan media, particularly radio, there is a need to rethink the nature of the coverage, which tends to neglect the contextual factors, such as local socio-economic and cultural factors within which environmental issues and problems occur and which, as this thesis establishes, greatly influences the way people make sense of environmental issues and problems. I posit that the Participatory Approach that seeks to address the communities’ most pressing concerns should be adopted – to include more of the communities’ voices and involve them in the production of radio programmes.
- Full Text:
- Date Issued: 2013
Modulation of Plasmodium falciparum chaperones PfHsp70-1 and PfHsp70-x by small molecules
- Authors: Cockburn, Ingrid Louise
- Date: 2013
- Subjects: Plasmodium falciparum Heat shock proteins Molecular chaperones Homeostasis Protein folding Malaria Antimalarials Escherichia coli
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3887 , http://hdl.handle.net/10962/d1001747
- Description: The heat shock proteins of ~ 70 kDa (Hsp70s) are a conserved group of molecular chaperones important in maintaining the protein homeostasis in cells, carrying out functions including refolding of misfolded or unfolded proteins. Hsp70s function in conjunction with a number of other proteins including Hsp40 cochaperones. Central to the regulation Hsp70 activity is the Hsp70 ATPase cycle, involving ATP hydrolysis by Hsp70, and stimulation of this ATP hydrolysis by Hsp40. PfHsp70-1, the major cytosolic Hsp70 in the malaria parasite, Plasmodium falciparum, and PfHsp70-x, a novel malarial Hsp70 recently found to be exported to the host cell cytosol during the erythrocytic stages of the P. falciparum lifecycle, are both thought to play important roles in the malaria parasite’s survival and virulence, and thus represent novel antimalarial targets. Modulation of the function of these proteins by small molecules could thus lead to the development of antimalarials with novel targets and mechanisms. In the present study, malarial Hsp70s (PfHsp70-1 and PfHsp70-x), human Hsp70 (HSPA1A), malarial Hsp40 (PfHsp40) and human Hsp40 (Hsj1a) were recombinantly produced in Escherichia coli. In a characterisation of the chaperone activity of recombinant PfHsp70-x, the protein was found to have a basal ATPase activity (15.7 nmol ATP/min/mg protein) comparable to that previously described for PfHsp70-1, and an aggregation suppression activity significantly higher than that of PfHsp70-1. In vitro assays were used to screen five compounds of interest (lapachol, bromo-β-lapachona and malonganenones A, B and C) belonging to two compound classes (1,4 naphthoquinones and prenylated alkaloids) for modulatory effects on PfHsp70-1, PfHsp70-x and HsHsp70. A wide range of effects by compounds on the chaperone activities of Hsp70s was observed, including differential effects by compounds on different Hsp70s despite high conservation (≥ 70 % sequence identity) between the Hsp70s. The five compounds were shown to interact with all three Hsp70s in in vitro binding studies. Differential modulation by compounds was observed between the Hsj1a-stimulated ATPase activities of different Hsp70s, suggestive of not only a high degree of specificity of compounds to chaperone systems, but also distinct interactions between different Hsp70s and Hjs1a. The effects of compounds on the survival of P. falciparum parasites as well as mammalian cells was assessed. Bromo-β-lapachona was found to have broad effects across all systems, modulating the chaperone activities of all three Hsp70s, and showing significant toxicity toward both P. falciparum parasites and mammalian cells in culture. Malonganenone A was found to modulate only the malarial Hsp70s, not human Hsp70, showing significant toxicity toward malarial parasites (IC₅₀ ~ 0.8 μM), and comparatively low toxicity toward mammalian cells, representing therefore a novel starting point for a new class of antimalarials potentially targeting a new antimalarial drug target, Hsp70.
- Full Text:
- Date Issued: 2013
- Authors: Cockburn, Ingrid Louise
- Date: 2013
- Subjects: Plasmodium falciparum Heat shock proteins Molecular chaperones Homeostasis Protein folding Malaria Antimalarials Escherichia coli
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3887 , http://hdl.handle.net/10962/d1001747
- Description: The heat shock proteins of ~ 70 kDa (Hsp70s) are a conserved group of molecular chaperones important in maintaining the protein homeostasis in cells, carrying out functions including refolding of misfolded or unfolded proteins. Hsp70s function in conjunction with a number of other proteins including Hsp40 cochaperones. Central to the regulation Hsp70 activity is the Hsp70 ATPase cycle, involving ATP hydrolysis by Hsp70, and stimulation of this ATP hydrolysis by Hsp40. PfHsp70-1, the major cytosolic Hsp70 in the malaria parasite, Plasmodium falciparum, and PfHsp70-x, a novel malarial Hsp70 recently found to be exported to the host cell cytosol during the erythrocytic stages of the P. falciparum lifecycle, are both thought to play important roles in the malaria parasite’s survival and virulence, and thus represent novel antimalarial targets. Modulation of the function of these proteins by small molecules could thus lead to the development of antimalarials with novel targets and mechanisms. In the present study, malarial Hsp70s (PfHsp70-1 and PfHsp70-x), human Hsp70 (HSPA1A), malarial Hsp40 (PfHsp40) and human Hsp40 (Hsj1a) were recombinantly produced in Escherichia coli. In a characterisation of the chaperone activity of recombinant PfHsp70-x, the protein was found to have a basal ATPase activity (15.7 nmol ATP/min/mg protein) comparable to that previously described for PfHsp70-1, and an aggregation suppression activity significantly higher than that of PfHsp70-1. In vitro assays were used to screen five compounds of interest (lapachol, bromo-β-lapachona and malonganenones A, B and C) belonging to two compound classes (1,4 naphthoquinones and prenylated alkaloids) for modulatory effects on PfHsp70-1, PfHsp70-x and HsHsp70. A wide range of effects by compounds on the chaperone activities of Hsp70s was observed, including differential effects by compounds on different Hsp70s despite high conservation (≥ 70 % sequence identity) between the Hsp70s. The five compounds were shown to interact with all three Hsp70s in in vitro binding studies. Differential modulation by compounds was observed between the Hsj1a-stimulated ATPase activities of different Hsp70s, suggestive of not only a high degree of specificity of compounds to chaperone systems, but also distinct interactions between different Hsp70s and Hjs1a. The effects of compounds on the survival of P. falciparum parasites as well as mammalian cells was assessed. Bromo-β-lapachona was found to have broad effects across all systems, modulating the chaperone activities of all three Hsp70s, and showing significant toxicity toward both P. falciparum parasites and mammalian cells in culture. Malonganenone A was found to modulate only the malarial Hsp70s, not human Hsp70, showing significant toxicity toward malarial parasites (IC₅₀ ~ 0.8 μM), and comparatively low toxicity toward mammalian cells, representing therefore a novel starting point for a new class of antimalarials potentially targeting a new antimalarial drug target, Hsp70.
- Full Text:
- Date Issued: 2013