Direct and indirect effects of zooplanktivorous predators on the estuarine plankton community
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
Writing left: Ruth First and radical South African journalism in the 1950's
- Authors: Pinnock, Don
- Date: 1992
- Subjects: First, Ruth, 1925-1982 Journalism -- Political aspects -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2822 , http://hdl.handle.net/10962/d1003032
- Description: In a prison cell in Johannesburg in 1953 after months of solitary confinement Ruth First, one of South Africa's finest investigative joumalists, attempted to commit suicide. In a sense, information for this thesis has been gathered around the question of why First felt her life had reached a point where she wished it extinguished. The answer involves who she was, what she believed in and her perception at that moment in time of the magnitude of the defeat of all she had worked for. But this question has broader implications - it has been asked because its answer throws light not only on the particular joumalist, but on the radical press and on the political movements which gave it both life and readers. This study is divided into six sections: Origins and influences looks, firstly, at early Jewish migrations and Ruth's life up to the end of her schooling in Johannesburg, then at her university years and the influence on her life of the Communist Party of South Africa. A vigorously provocative life traces debates which led to the formation of the South African Congress of Democrats and the Congress Alliance. It looks, also, at the political influence of the white Left and the radical social fratemity. Trumpeters of freedom locates the origins of the radical press tradition in South Africa, then looks at the development of the two publications to which Ruth devoted most of her time: The Guardian/New Age and Fighting Talk. Writing left focuses on First's writing in connection with three campaigns: the farm labour and the potato boycott, womens' passes and the bus boycotts. These chapters are not a history of these campaigns, but an analysis of the influence on them of First's joumalism. Word wars is about the Treason Trial of 1956. The contention here is that the trial, in which First was one of the 'chief co-conspirators ', not only put the Congress Alliance in the dock, but was about the definition of three words: communism, violence and treason. In many ways it was a trial of the language of the Left, the tools of First's trade. Shifting focus looks at the period after Sharpeville and the 1960 State of Emergency. It considers the shift in First's writing necessitated by greater political oppression, a banning order and her exploration of the writing of books. Chapter 12 considers the massive setback to the Congress Alliance of the Rivonia Trial and the tactical errors which led the Congress leadership to the conclusion that armed struggle would succeed at that point in time. The final chapter is about First's detention, and her perceived personal defeat which resulted in her attempted suicide. The Postscript looks at First's successful attempts to come to terms with both a political and personal defeat. The work effectively ends, however, with her departure from South Africa.
- Full Text:
- Date Issued: 1992
- Authors: Pinnock, Don
- Date: 1992
- Subjects: First, Ruth, 1925-1982 Journalism -- Political aspects -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2822 , http://hdl.handle.net/10962/d1003032
- Description: In a prison cell in Johannesburg in 1953 after months of solitary confinement Ruth First, one of South Africa's finest investigative joumalists, attempted to commit suicide. In a sense, information for this thesis has been gathered around the question of why First felt her life had reached a point where she wished it extinguished. The answer involves who she was, what she believed in and her perception at that moment in time of the magnitude of the defeat of all she had worked for. But this question has broader implications - it has been asked because its answer throws light not only on the particular joumalist, but on the radical press and on the political movements which gave it both life and readers. This study is divided into six sections: Origins and influences looks, firstly, at early Jewish migrations and Ruth's life up to the end of her schooling in Johannesburg, then at her university years and the influence on her life of the Communist Party of South Africa. A vigorously provocative life traces debates which led to the formation of the South African Congress of Democrats and the Congress Alliance. It looks, also, at the political influence of the white Left and the radical social fratemity. Trumpeters of freedom locates the origins of the radical press tradition in South Africa, then looks at the development of the two publications to which Ruth devoted most of her time: The Guardian/New Age and Fighting Talk. Writing left focuses on First's writing in connection with three campaigns: the farm labour and the potato boycott, womens' passes and the bus boycotts. These chapters are not a history of these campaigns, but an analysis of the influence on them of First's joumalism. Word wars is about the Treason Trial of 1956. The contention here is that the trial, in which First was one of the 'chief co-conspirators ', not only put the Congress Alliance in the dock, but was about the definition of three words: communism, violence and treason. In many ways it was a trial of the language of the Left, the tools of First's trade. Shifting focus looks at the period after Sharpeville and the 1960 State of Emergency. It considers the shift in First's writing necessitated by greater political oppression, a banning order and her exploration of the writing of books. Chapter 12 considers the massive setback to the Congress Alliance of the Rivonia Trial and the tactical errors which led the Congress leadership to the conclusion that armed struggle would succeed at that point in time. The final chapter is about First's detention, and her perceived personal defeat which resulted in her attempted suicide. The Postscript looks at First's successful attempts to come to terms with both a political and personal defeat. The work effectively ends, however, with her departure from South Africa.
- Full Text:
- Date Issued: 1992
The impact of policies on development-induced resettlement processes and outcomes: a Lesotho-India comparative study
- Tsietsi, Teboho Priscilla Mosuoe
- Authors: Tsietsi, Teboho Priscilla Mosuoe
- Date: 2019
- Subjects: Forced migration -- Lesotho , Forced migration -- India , Dams -- Social aspects -- Lesotho , Dams -- Social aspects -- India , Irrigation projects -- Economic aspects -- Lesotho , Irrigation projects -- Economic aspects -- India , Land settlement -- Government policy -- Lesotho , Land settlement -- Government policy -- India
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72307 , vital:30032
- Description: The practice of Development-Induced Displacement and Resettlement (DIDR), historically, has often led to negative consequences for those affected by development projects, including but not limited to, the construction of large dams. Although DIDR arises from the need to provide goods and services that characterise development, it often leaves those who are forced to give up their assets, resources, and long standing social networks in dire socio-economic conditions as a result of resettlement. In many such cases, the provision for losses suffered by those primarily affected is often insufficient, leading to further losses experienced as a result of the complete life change experienced by those affected by resettlement. Research has shown that the insufficiency of such provisions for losses is attributable to not only the value of the provision itself, but also the manner in which resettlement processes are implemented. While early on, researchers believed that the development of policies would have a significant, positive impact on the practice of resettlement and its outcomes, evidence would later show that the development of policies alone is not a panacea for all challenges associated with forced resettlement. Further research revealed that resettlement is characterised by inherent and active complexities which are often at play, and may impede effective implementation. Hence, while the development of policies is essential, both the development and implementation of policies must be undertaken in a manner that seeks to actively address the inherent complexities of resettlement. This thesis aims to explore the implementation of resettlement policies in two case studies, where in one case, resettlement was informed by national policy, and in the other, by policies developed by a parastatal tasked with the responsibility of executing resettlement. The study makes a comparative analysis between the two cases, and explores the factors at play in the implementation of resettlement policies – whether such factors serve to facilitate or impede effective implementation – as well as the nature of the outcomes on the ground. As an overarching goal, the research aims to provide a basis upon which a framework for the development of a national level policy of resettlement may be developed. In this regard, the thesis undertakes a comparison of the Indian resettlement case with the Lesotho case. The former, in addition to having developed a resettlement policy at the national level, has a long history of experience in forced resettlement and displacement, from which invaluable lessons have been learned. The latter, on the other hand, has no resettlement policy at the national level, although the country has also experienced forced resettlement dating back to nearly three decades ago. Although India and Lesotho have distinct social, cultural, economic and demographic characteristics, research has shown that the complexities of forced resettlement, and their outcomes on affected people, are largely applicable across the different contexts. Hence, certain dimensions and lessons can be transferable from the Indian case to the Lesotho case, and vice versa. However, for the purpose of this thesis, the focus is on providing a basis for national policy development in Lesotho, in light of Indian policies and practice. The empirical basis of the thesis is an ethnographic study undertaken in relation to the Chandil Dam resettlement case in Jharkhand, India and the Mohale Dam resettlement case in Maseru, Lesotho. The thesis engaged both qualitative and quantitative research methods, as well as four, complementary theoretical tools that analyse the effects of forced resettlement on affected people. The thesis reveals that the negative consequences of forced resettlement resulting from its inherent complexities continue to manifest with concerning effects on the lives of those affected. It shows that the implementation of policies is a complex process that requires collaborative effort from a wide range of stakeholders in a given context. National policies of resettlement are, thus, instrumental in this regard, as they can create an enabling environment for the facilitation of collaborative efforts towards sustainable livelihood re-establishment for those who involuntarily suffer losses to resettlement.
- Full Text:
- Date Issued: 2019
- Authors: Tsietsi, Teboho Priscilla Mosuoe
- Date: 2019
- Subjects: Forced migration -- Lesotho , Forced migration -- India , Dams -- Social aspects -- Lesotho , Dams -- Social aspects -- India , Irrigation projects -- Economic aspects -- Lesotho , Irrigation projects -- Economic aspects -- India , Land settlement -- Government policy -- Lesotho , Land settlement -- Government policy -- India
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72307 , vital:30032
- Description: The practice of Development-Induced Displacement and Resettlement (DIDR), historically, has often led to negative consequences for those affected by development projects, including but not limited to, the construction of large dams. Although DIDR arises from the need to provide goods and services that characterise development, it often leaves those who are forced to give up their assets, resources, and long standing social networks in dire socio-economic conditions as a result of resettlement. In many such cases, the provision for losses suffered by those primarily affected is often insufficient, leading to further losses experienced as a result of the complete life change experienced by those affected by resettlement. Research has shown that the insufficiency of such provisions for losses is attributable to not only the value of the provision itself, but also the manner in which resettlement processes are implemented. While early on, researchers believed that the development of policies would have a significant, positive impact on the practice of resettlement and its outcomes, evidence would later show that the development of policies alone is not a panacea for all challenges associated with forced resettlement. Further research revealed that resettlement is characterised by inherent and active complexities which are often at play, and may impede effective implementation. Hence, while the development of policies is essential, both the development and implementation of policies must be undertaken in a manner that seeks to actively address the inherent complexities of resettlement. This thesis aims to explore the implementation of resettlement policies in two case studies, where in one case, resettlement was informed by national policy, and in the other, by policies developed by a parastatal tasked with the responsibility of executing resettlement. The study makes a comparative analysis between the two cases, and explores the factors at play in the implementation of resettlement policies – whether such factors serve to facilitate or impede effective implementation – as well as the nature of the outcomes on the ground. As an overarching goal, the research aims to provide a basis upon which a framework for the development of a national level policy of resettlement may be developed. In this regard, the thesis undertakes a comparison of the Indian resettlement case with the Lesotho case. The former, in addition to having developed a resettlement policy at the national level, has a long history of experience in forced resettlement and displacement, from which invaluable lessons have been learned. The latter, on the other hand, has no resettlement policy at the national level, although the country has also experienced forced resettlement dating back to nearly three decades ago. Although India and Lesotho have distinct social, cultural, economic and demographic characteristics, research has shown that the complexities of forced resettlement, and their outcomes on affected people, are largely applicable across the different contexts. Hence, certain dimensions and lessons can be transferable from the Indian case to the Lesotho case, and vice versa. However, for the purpose of this thesis, the focus is on providing a basis for national policy development in Lesotho, in light of Indian policies and practice. The empirical basis of the thesis is an ethnographic study undertaken in relation to the Chandil Dam resettlement case in Jharkhand, India and the Mohale Dam resettlement case in Maseru, Lesotho. The thesis engaged both qualitative and quantitative research methods, as well as four, complementary theoretical tools that analyse the effects of forced resettlement on affected people. The thesis reveals that the negative consequences of forced resettlement resulting from its inherent complexities continue to manifest with concerning effects on the lives of those affected. It shows that the implementation of policies is a complex process that requires collaborative effort from a wide range of stakeholders in a given context. National policies of resettlement are, thus, instrumental in this regard, as they can create an enabling environment for the facilitation of collaborative efforts towards sustainable livelihood re-establishment for those who involuntarily suffer losses to resettlement.
- Full Text:
- Date Issued: 2019
An exploratory study of a virtual partnership for building capacity in a tertiary education institution
- Mufeti, Tulimevava Kaunapawa
- Authors: Mufeti, Tulimevava Kaunapawa
- Date: 2013-03-20
- Subjects: Internet in higher education Education, Higher -- Computer-assisted instruction Education, Higher -- Technological innovations Computer-assisted instruction -- Africa, Southern Education, Higher -- Africa, Southern Educational technology -- Africa, Southern SANTED Virtual Classroom Project
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1134 , http://hdl.handle.net/10962/d1001624
- Description: Collaborative partnerships aimed at strengthening institutional capacities are a long established trend in academia. Recent developments in Information and Communications Technologies (ICTs) have fostered a renewed interest in collaborative initiatives in the academic sphere, however, and at the same time, have created new ways of working together. Current research models do not provide sufficient methods to guide collaborations in capacity-building processes in virtual environments, especially in contexts associated with inadequate resources. Conceptual tools are therefore needed to guide the implementation of partnerships that use technology to mediate capacity building in these contexts. This research study was aimed at understanding whether and how virtual partnerships can be used to facilitate capacity building in tertiary education institutions in the SADC region. It is based on a single case study of the SANTED Virtual Classroom Project, a partnership between the Departments of Computer Science at Rhodes University (RU) and the University of Namibia (UNAM). In the project, ICTs were used to mediate the process of building teaching and research capacity in the department at UNAM. The dynamics of the partnership are explored as the implementation process developed over a period of three years. The research adopted a sociocultural perspective in the analysis of the project‟s implementation. It uses activity theory and the notion of communities of practice as conceptual frameworks to explore how the two departments organised themselves and how they harnessed the virtual environment to enable the capacity-building partnership. Activity theory provided a lens to understand the complex relationships between the different elements of the partnership activities mediated by technological tools. The concept of communities of practice, on the other hand, enabled participants‟ progress to be analysed, as they went through the various transition stages of the capacity-building process. The thesis identifies the following four categories of challenges inherent in the implementation of virtual partnerships: infrastructural, institutional, cultural and individual expectations. It also emphasises the need for identifying the different transition stages corresponding to the levels of participation in the capacity-building process. The thesis recommends that the implementation of virtual partnerships for capacity building purposes in the SADC region must focus on: identifying the appropriate capacity building strategies at Abstract ii each transition stage; finding appropriate, light-weight virtual classroom solutions; identifying appropriate pedagogic models to suit available technology; addressing systemic tensions that can arise as a result of different institutional cultures; and developing and nurturing virtual communities of practice to ensure sustainability. The research findings contribute to the body of knowledge exploring the use of technologies to develop and strengthen human resource capacities in developing contexts in a sustainable way. More importantly, it contributes to the literature on collaborative virtual partnerships in the SADC region, and demonstrates one way in which the operations of such a partnership may be supported in similar contexts , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Authors: Mufeti, Tulimevava Kaunapawa
- Date: 2013-03-20
- Subjects: Internet in higher education Education, Higher -- Computer-assisted instruction Education, Higher -- Technological innovations Computer-assisted instruction -- Africa, Southern Education, Higher -- Africa, Southern Educational technology -- Africa, Southern SANTED Virtual Classroom Project
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1134 , http://hdl.handle.net/10962/d1001624
- Description: Collaborative partnerships aimed at strengthening institutional capacities are a long established trend in academia. Recent developments in Information and Communications Technologies (ICTs) have fostered a renewed interest in collaborative initiatives in the academic sphere, however, and at the same time, have created new ways of working together. Current research models do not provide sufficient methods to guide collaborations in capacity-building processes in virtual environments, especially in contexts associated with inadequate resources. Conceptual tools are therefore needed to guide the implementation of partnerships that use technology to mediate capacity building in these contexts. This research study was aimed at understanding whether and how virtual partnerships can be used to facilitate capacity building in tertiary education institutions in the SADC region. It is based on a single case study of the SANTED Virtual Classroom Project, a partnership between the Departments of Computer Science at Rhodes University (RU) and the University of Namibia (UNAM). In the project, ICTs were used to mediate the process of building teaching and research capacity in the department at UNAM. The dynamics of the partnership are explored as the implementation process developed over a period of three years. The research adopted a sociocultural perspective in the analysis of the project‟s implementation. It uses activity theory and the notion of communities of practice as conceptual frameworks to explore how the two departments organised themselves and how they harnessed the virtual environment to enable the capacity-building partnership. Activity theory provided a lens to understand the complex relationships between the different elements of the partnership activities mediated by technological tools. The concept of communities of practice, on the other hand, enabled participants‟ progress to be analysed, as they went through the various transition stages of the capacity-building process. The thesis identifies the following four categories of challenges inherent in the implementation of virtual partnerships: infrastructural, institutional, cultural and individual expectations. It also emphasises the need for identifying the different transition stages corresponding to the levels of participation in the capacity-building process. The thesis recommends that the implementation of virtual partnerships for capacity building purposes in the SADC region must focus on: identifying the appropriate capacity building strategies at Abstract ii each transition stage; finding appropriate, light-weight virtual classroom solutions; identifying appropriate pedagogic models to suit available technology; addressing systemic tensions that can arise as a result of different institutional cultures; and developing and nurturing virtual communities of practice to ensure sustainability. The research findings contribute to the body of knowledge exploring the use of technologies to develop and strengthen human resource capacities in developing contexts in a sustainable way. More importantly, it contributes to the literature on collaborative virtual partnerships in the SADC region, and demonstrates one way in which the operations of such a partnership may be supported in similar contexts , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
A structural investigation of the sulphated polysaccharides of Aeodes orbitosa and Phyllymenia cornea
- Authors: Parolis, Haralambos
- Date: 1968
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4487 , http://hdl.handle.net/10962/d1012999
- Description: A highly sulphated, methylated polysaccharide, aeodan, isolated from the red seaweed Aeodes orbitosa was shown to contain galactose, 2-̲̲O-methyl-D-galactose, 4-O̲-methyl-Lgalactose, 6-O̲-methyl-D-galactose, xylose, and glycerol. The polysaccharide was desulphated with methanolic hydrogen chloride. Periodate oxidation of aeodan and desulphated aeodan, followed by reduction and hydrolysis, revealed the presence of 1,4- and 1,3-linked galactose residues and 1,3-linked 6-O̲-methy l-D-galactose residues in aeodan. Treatment of aeodan with sodium hydroxide revealed that the majority of the ester sulphate groups were alkali stable. Methylation of desulphated aeodan revealed that the polysaccharide was composed entirely of 1,3 and 1,4 links. Methylation of aeodan revealed the presence of 1,3- and 1,4- linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose-2, 6-disulphate units in the polysaccharide. Partial hydrolysis of aeodan resulted in the isolation and characterisation of 3-O̲-D-galactopyranosyl-D-galactose and 4-O̲-ß-D-galactopyranosyl- D-galactose. A sulphated, methylated polysaccharide, phyllymenan, isolated from the red seaweed Phyllymenia cornea was shown to contain galactose, 2-O̲-methyl-D-galactose, 4-O̲-methyl L- galactose , 6-O̲-methyl -D-galactose, and xylose. The polysaccharide was completely desulphated with methanolic hydrogen chloride. Periodate oxidation of phyllymenan before and after desulphation revealed that removal of the sulphate ester groups had not produced any new adjacent hydroxyl groups. Alkali treatment of phyllymenan revealed that the ester sulphate groups were alkali stable. Methylation studies on phyllymenan revealed the presence of 1,3- and 1,4-linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose- 2,6-disulphate units in the polysaccharide. Partial hydrolysis of phyllymenan revealed the presence or 4-O-̲ß- D-Dgalactopyranosyl- D-galactosc, 4-O-̲ß-D-galactopyranosyl -2-0- methyl-D-galactose, a galactosylgalactose composed of D and L-galactose, and adjacent 6-O̲-methyl- and 2-O̲-methyl-D- galactose units in the polysaccharide.
- Full Text:
- Date Issued: 1968
- Authors: Parolis, Haralambos
- Date: 1968
- Subjects: Polysaccharides , Marine algae -- Composition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4487 , http://hdl.handle.net/10962/d1012999
- Description: A highly sulphated, methylated polysaccharide, aeodan, isolated from the red seaweed Aeodes orbitosa was shown to contain galactose, 2-̲̲O-methyl-D-galactose, 4-O̲-methyl-Lgalactose, 6-O̲-methyl-D-galactose, xylose, and glycerol. The polysaccharide was desulphated with methanolic hydrogen chloride. Periodate oxidation of aeodan and desulphated aeodan, followed by reduction and hydrolysis, revealed the presence of 1,4- and 1,3-linked galactose residues and 1,3-linked 6-O̲-methy l-D-galactose residues in aeodan. Treatment of aeodan with sodium hydroxide revealed that the majority of the ester sulphate groups were alkali stable. Methylation of desulphated aeodan revealed that the polysaccharide was composed entirely of 1,3 and 1,4 links. Methylation of aeodan revealed the presence of 1,3- and 1,4- linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose-2, 6-disulphate units in the polysaccharide. Partial hydrolysis of aeodan resulted in the isolation and characterisation of 3-O̲-D-galactopyranosyl-D-galactose and 4-O̲-ß-D-galactopyranosyl- D-galactose. A sulphated, methylated polysaccharide, phyllymenan, isolated from the red seaweed Phyllymenia cornea was shown to contain galactose, 2-O̲-methyl-D-galactose, 4-O̲-methyl L- galactose , 6-O̲-methyl -D-galactose, and xylose. The polysaccharide was completely desulphated with methanolic hydrogen chloride. Periodate oxidation of phyllymenan before and after desulphation revealed that removal of the sulphate ester groups had not produced any new adjacent hydroxyl groups. Alkali treatment of phyllymenan revealed that the ester sulphate groups were alkali stable. Methylation studies on phyllymenan revealed the presence of 1,3- and 1,4-linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose- 2,6-disulphate units in the polysaccharide. Partial hydrolysis of phyllymenan revealed the presence or 4-O-̲ß- D-Dgalactopyranosyl- D-galactosc, 4-O-̲ß-D-galactopyranosyl -2-0- methyl-D-galactose, a galactosylgalactose composed of D and L-galactose, and adjacent 6-O̲-methyl- and 2-O̲-methyl-D- galactose units in the polysaccharide.
- Full Text:
- Date Issued: 1968
The African press in South Africa
- Authors: St Leger, Frederick York
- Date: 1975
- Subjects: Press -- South Africa -- History Ethnic press -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3328 , http://hdl.handle.net/10962/d1003116
- Description: In a plural society, riven by deep conflict, as is South Africa, where however the Press retains a considerable measure of freedom to contribute to the political process it is the political role which is of the greatest significance rather than, for example, the reflection by the Press of social values or the internal organisation of the Press as a social system. Although it is, of course, hardly possible completely to ignore these other aspects in any institutional study.
- Full Text:
- Date Issued: 1975
- Authors: St Leger, Frederick York
- Date: 1975
- Subjects: Press -- South Africa -- History Ethnic press -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3328 , http://hdl.handle.net/10962/d1003116
- Description: In a plural society, riven by deep conflict, as is South Africa, where however the Press retains a considerable measure of freedom to contribute to the political process it is the political role which is of the greatest significance rather than, for example, the reflection by the Press of social values or the internal organisation of the Press as a social system. Although it is, of course, hardly possible completely to ignore these other aspects in any institutional study.
- Full Text:
- Date Issued: 1975
Investigations into the ecology of a population of Citrus Red Scale (Aonidiella aurantii Mask.) in the Swaziland lowlands
- Authors: Atkinson, P R
- Date: 1982
- Subjects: Citrus -- Diseases and pests -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5619 , http://hdl.handle.net/10962/d1003733
- Description: In the Swaziland lowlands, biological control of the citrus pest red scale, Aonidiella aurantii (Mask), has been consistently unsuccessful although it is successful in middle altitude regions. However, recent cases of resistance to organophosphate insecticides elsewhere in southern Africa, make it important to reconsider biological control of red scale in the lowlands. Should similar resistance be evolved in this region, the pest could be controlled only by natural means together with oils. This account attempts to answer questions about the natural control of a red scale population in the lowlands, by examining data collected between 1972 and 1975. The population was continuously breeding with overlapped generations. It consisted of three sections, on leaves, twigs and fruit, having different rates of reproduction, development and mortality. These sections are considered separately but that on leaves, being relatively unimportant, is largely ignored. The generation mortality is estimated in the sections on twigs and fruit and related to climatic and biotic indices. The causes of seasonal and between-years variation in the sections on twigs and fruit are elucidated. The effectiveness of each kind of natural enemy is examined and the factors affecting natural enemy numbers are investigated. The question of population regulation is discussed. Differences in mean infestation levels in middle altitude and lowland regions are explained in terms of different rates of reproduction and mortality.
- Full Text:
- Date Issued: 1982
- Authors: Atkinson, P R
- Date: 1982
- Subjects: Citrus -- Diseases and pests -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5619 , http://hdl.handle.net/10962/d1003733
- Description: In the Swaziland lowlands, biological control of the citrus pest red scale, Aonidiella aurantii (Mask), has been consistently unsuccessful although it is successful in middle altitude regions. However, recent cases of resistance to organophosphate insecticides elsewhere in southern Africa, make it important to reconsider biological control of red scale in the lowlands. Should similar resistance be evolved in this region, the pest could be controlled only by natural means together with oils. This account attempts to answer questions about the natural control of a red scale population in the lowlands, by examining data collected between 1972 and 1975. The population was continuously breeding with overlapped generations. It consisted of three sections, on leaves, twigs and fruit, having different rates of reproduction, development and mortality. These sections are considered separately but that on leaves, being relatively unimportant, is largely ignored. The generation mortality is estimated in the sections on twigs and fruit and related to climatic and biotic indices. The causes of seasonal and between-years variation in the sections on twigs and fruit are elucidated. The effectiveness of each kind of natural enemy is examined and the factors affecting natural enemy numbers are investigated. The question of population regulation is discussed. Differences in mean infestation levels in middle altitude and lowland regions are explained in terms of different rates of reproduction and mortality.
- Full Text:
- Date Issued: 1982
The ecology and management of the fishes of the Okavango Delta, Botswana, with particular reference to the role of the seasonal floods
- Authors: Merron, Glen Steven
- Date: 1991
- Subjects: Fishes -- Ecology -- Botswana Fishes -- Botswana -- Okavango River Delta
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5268 , http://hdl.handle.net/10962/d1005112
- Description: The Okavango is a vast inland delta system in northern Botswana which receives an annual flood from the highlands of southern Angola. There are distinct communities of fish in the Okavango which can be separated from each other by the physical characteristics of the different habitat types with which they co-evolved. This thesis provides an account of the biology and ecology of selected fish species in the Okavango Delta. Their response to the annual flood regime, and the environmental factors which limit their distribution and abundance, are examined. The thesis emphasizes the importance of water fluctuations in determining the nature of the fish fauna and the reaction of the fishes in terms of community structure, movements, breeding, predator-prey interactions and feeding. Four major ecotones were studied in the Okavango Delta. In the riverine floodplain and perennial swamp ecotones a higher species diversity was recorded than in the seasonal swamp and drainage rivers ecotones where diversity was lowest and comprised mainly of smaller fish species. A greater variety of habitat types was associated with the riverine floodplain and perennial swamp relative to the seasonal swamp and drainage rivers. The variety of habitat types between ecotones is associated with the degree of flood inundation in the respective ecotones. During the course of this study, annual recruitment of fish into the drainage rivers was from refugia in the seasonal swamp whereas the greatest degree of lateral and longitudinal movement was in the riverine floodplain and perennial swamp. Movement was in response to both biological requirements, such as availability of food and spawning sites, and physical features of the environment, such as the changing water depth. The total catch per unit effort (CPUE) of fish throughout the year was more constant in the riverine floodplain and perennial swamp than in the seasonal swamp and drainage rivers where CPUE fluctutated widely. An increase in CPUE during the duration of this study was apparent and related to the magnitude of the annual flood. In contrast to most other African wetlands, the arrival of the annual flood in the Okavango Delta coincides largely with the dry winter months. This situation presented an opportunity to compare the influence of floods and water temperature on the reproductive biology of the selected fish species. The results show a definite pattern and indicate that both the flood cycle and increased water temperatures greatly influence the breeding cycles of the selected species. The tilapia Oreochromis andersonii exhibited a considerable degree of phenotypic plasticity. Fish from the seasonally inundated areas showed a smaller mean size, egg size and larger number of eggs relative to fish in the perennially flooded areas. The size at sexual maturity was also smaller. These different reproductive characteristics exhibited by O. andersonii are dependent on the degree of water retention in the different habitats. The fishes of the Okavango have adopted other reproductive strategies to survive the changing environmental conditions brought about by an annual flood cycle. These strategies include the construction of foam nests, as described for Hepsetus odoe, for guarding the young and to provide an oxygen-rich environment. Two main non-piscivorous feeding pathways were identified in the Okavango. These are a detritus pathway based on dead plant and animal material, and an epiphyte pathway, based on algae and invertebrates that are attached to plant stems. Seasonal changes in diet in relation to the annual flood were recorded. The most dramrtic change was demonstrated by the catfish Clarias gariepinus which congregates in mass aggregations in the northern regions of the Delta and hunt in packs. Pack-hunting by catfish is a regular response to the annual fluctuations in water level. It is my conclusion that the main flow of biotic and abiotic stimuli within the Okavango Delta originates from the relatively hydrologically stable riverine floodplain and perennial swamp ecotones to the widely fluctuating seasonal swamp and drainage rivers ecotones. The relatively stable ecotones allow a diverse and biotically interdependent fish community to develop, whereas the widely fluctuating seasonal swamp and drainage rivers ecotones are characterized by a less diverse and interdependent fish community. The degree of abiotic and biotic interdependence among fish in an ecotone is very important for the long term management of the Okavango Delta. Potential developers have to determine whether the effect of a given action by man is likely to result in a long term disturbance or merely in an elastic recoil to a more or less similar state. Recommendations are made on the conservation and management of Okavango fishes taking into account the ecological characteristics of the delta.
- Full Text:
- Date Issued: 1991
- Authors: Merron, Glen Steven
- Date: 1991
- Subjects: Fishes -- Ecology -- Botswana Fishes -- Botswana -- Okavango River Delta
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5268 , http://hdl.handle.net/10962/d1005112
- Description: The Okavango is a vast inland delta system in northern Botswana which receives an annual flood from the highlands of southern Angola. There are distinct communities of fish in the Okavango which can be separated from each other by the physical characteristics of the different habitat types with which they co-evolved. This thesis provides an account of the biology and ecology of selected fish species in the Okavango Delta. Their response to the annual flood regime, and the environmental factors which limit their distribution and abundance, are examined. The thesis emphasizes the importance of water fluctuations in determining the nature of the fish fauna and the reaction of the fishes in terms of community structure, movements, breeding, predator-prey interactions and feeding. Four major ecotones were studied in the Okavango Delta. In the riverine floodplain and perennial swamp ecotones a higher species diversity was recorded than in the seasonal swamp and drainage rivers ecotones where diversity was lowest and comprised mainly of smaller fish species. A greater variety of habitat types was associated with the riverine floodplain and perennial swamp relative to the seasonal swamp and drainage rivers. The variety of habitat types between ecotones is associated with the degree of flood inundation in the respective ecotones. During the course of this study, annual recruitment of fish into the drainage rivers was from refugia in the seasonal swamp whereas the greatest degree of lateral and longitudinal movement was in the riverine floodplain and perennial swamp. Movement was in response to both biological requirements, such as availability of food and spawning sites, and physical features of the environment, such as the changing water depth. The total catch per unit effort (CPUE) of fish throughout the year was more constant in the riverine floodplain and perennial swamp than in the seasonal swamp and drainage rivers where CPUE fluctutated widely. An increase in CPUE during the duration of this study was apparent and related to the magnitude of the annual flood. In contrast to most other African wetlands, the arrival of the annual flood in the Okavango Delta coincides largely with the dry winter months. This situation presented an opportunity to compare the influence of floods and water temperature on the reproductive biology of the selected fish species. The results show a definite pattern and indicate that both the flood cycle and increased water temperatures greatly influence the breeding cycles of the selected species. The tilapia Oreochromis andersonii exhibited a considerable degree of phenotypic plasticity. Fish from the seasonally inundated areas showed a smaller mean size, egg size and larger number of eggs relative to fish in the perennially flooded areas. The size at sexual maturity was also smaller. These different reproductive characteristics exhibited by O. andersonii are dependent on the degree of water retention in the different habitats. The fishes of the Okavango have adopted other reproductive strategies to survive the changing environmental conditions brought about by an annual flood cycle. These strategies include the construction of foam nests, as described for Hepsetus odoe, for guarding the young and to provide an oxygen-rich environment. Two main non-piscivorous feeding pathways were identified in the Okavango. These are a detritus pathway based on dead plant and animal material, and an epiphyte pathway, based on algae and invertebrates that are attached to plant stems. Seasonal changes in diet in relation to the annual flood were recorded. The most dramrtic change was demonstrated by the catfish Clarias gariepinus which congregates in mass aggregations in the northern regions of the Delta and hunt in packs. Pack-hunting by catfish is a regular response to the annual fluctuations in water level. It is my conclusion that the main flow of biotic and abiotic stimuli within the Okavango Delta originates from the relatively hydrologically stable riverine floodplain and perennial swamp ecotones to the widely fluctuating seasonal swamp and drainage rivers ecotones. The relatively stable ecotones allow a diverse and biotically interdependent fish community to develop, whereas the widely fluctuating seasonal swamp and drainage rivers ecotones are characterized by a less diverse and interdependent fish community. The degree of abiotic and biotic interdependence among fish in an ecotone is very important for the long term management of the Okavango Delta. Potential developers have to determine whether the effect of a given action by man is likely to result in a long term disturbance or merely in an elastic recoil to a more or less similar state. Recommendations are made on the conservation and management of Okavango fishes taking into account the ecological characteristics of the delta.
- Full Text:
- Date Issued: 1991
Witwatersrand genesis: a comparative study of some early gold mining companies, 1886-1894
- Authors: Webb, Arthur (Arthur C M)
- Date: 1982
- Subjects: Gold mines and mining -- South Africa -- History Gold mines and mining -- South Africa -- Witwatersrand -- History Ferreira Gold Mining Company (Firm) Witwatersrand Gold Mining Company (Firm) Simmer and Jack Gold Mining Company (Firm) Wemmer Gold Mining Company (Firm)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1029 , http://hdl.handle.net/10962/d1003725
- Description: Preface: For anyone standing on the ridge of the Witwatersrand on a spring day in September 1886 the sight immediately to the south represented a hive of activity and hope. Nearly a hundred years later ample evidence stretches away on both sides of the watershed to confirm the fulfilment of those early sentiments. It is, nevertheless, all too easy to ignore the struggles and failures which marked the beginnings of the world's greatest gold field in the light of its subsequent abundant success. Only when attention is turned to the individual companies formed to exploit the discovery does the true picture emerge of the lack of adequate technological and managerial knowledge amongst the early pioneers and of the financial frailty of their companies. The object of this thesis is to shed light on these beginnings by reviewing the histories of four of the earliest companies established to work the main reef. The approach adopted is to scrutinize the material available with a view to determining the motivations and actions of the managements of the various companies with regard to their economic environment, whether within or without the individual company. Clearly, the availability of information is a major determinant of the success of any such venture and this was particularly so in the case of the companies considered. With the exception of the Barlow Rand Limited holding of the H. Eckstein and Company Archives, which offers an integral coverage of that firm's dealings with the emerging industry, and which is certainly the most comprehensive source of information available to the researcher, little material relating to specific gold mining companies has survived. Under these circumstances it was necessary to rely heavily for information on the local press. These newspapers proved an invaluable source in this regard. As a mining camp with a limited capacity for generating newsworthy incidents, the newspapers of early Johannesburg found an eager readership for information about the industry which lay at the heart of the community. For their part, the managements of the various mining companies found in the pages of the local press an outlet for intelligence both true and false; the press was a useful vehicle for the publication of directors' and annual reports to meet a wider audience, but similarly it could be and was used to disseminate 'spectacular' reports calculated to influence the status of a company's stock on the local share market. As a research source the press has thus to be approached with caution but its value, if the warning is heeded, is in no way diminished. Beyond these two sources the next most valuable accumulation of data on the early industry is "The Gold Fields Collection" housed in the Cory Library for Historical Research at Rhodes University. As a collection it is far from complete and it is to be hoped that the donors will in future see fit to augment it with further material as this becomes available. It neverthess proved an invaluable source for the investigation of at least one of the companies of the study and for a general background to the industry.
- Full Text:
- Date Issued: 1982
- Authors: Webb, Arthur (Arthur C M)
- Date: 1982
- Subjects: Gold mines and mining -- South Africa -- History Gold mines and mining -- South Africa -- Witwatersrand -- History Ferreira Gold Mining Company (Firm) Witwatersrand Gold Mining Company (Firm) Simmer and Jack Gold Mining Company (Firm) Wemmer Gold Mining Company (Firm)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1029 , http://hdl.handle.net/10962/d1003725
- Description: Preface: For anyone standing on the ridge of the Witwatersrand on a spring day in September 1886 the sight immediately to the south represented a hive of activity and hope. Nearly a hundred years later ample evidence stretches away on both sides of the watershed to confirm the fulfilment of those early sentiments. It is, nevertheless, all too easy to ignore the struggles and failures which marked the beginnings of the world's greatest gold field in the light of its subsequent abundant success. Only when attention is turned to the individual companies formed to exploit the discovery does the true picture emerge of the lack of adequate technological and managerial knowledge amongst the early pioneers and of the financial frailty of their companies. The object of this thesis is to shed light on these beginnings by reviewing the histories of four of the earliest companies established to work the main reef. The approach adopted is to scrutinize the material available with a view to determining the motivations and actions of the managements of the various companies with regard to their economic environment, whether within or without the individual company. Clearly, the availability of information is a major determinant of the success of any such venture and this was particularly so in the case of the companies considered. With the exception of the Barlow Rand Limited holding of the H. Eckstein and Company Archives, which offers an integral coverage of that firm's dealings with the emerging industry, and which is certainly the most comprehensive source of information available to the researcher, little material relating to specific gold mining companies has survived. Under these circumstances it was necessary to rely heavily for information on the local press. These newspapers proved an invaluable source in this regard. As a mining camp with a limited capacity for generating newsworthy incidents, the newspapers of early Johannesburg found an eager readership for information about the industry which lay at the heart of the community. For their part, the managements of the various mining companies found in the pages of the local press an outlet for intelligence both true and false; the press was a useful vehicle for the publication of directors' and annual reports to meet a wider audience, but similarly it could be and was used to disseminate 'spectacular' reports calculated to influence the status of a company's stock on the local share market. As a research source the press has thus to be approached with caution but its value, if the warning is heeded, is in no way diminished. Beyond these two sources the next most valuable accumulation of data on the early industry is "The Gold Fields Collection" housed in the Cory Library for Historical Research at Rhodes University. As a collection it is far from complete and it is to be hoped that the donors will in future see fit to augment it with further material as this becomes available. It neverthess proved an invaluable source for the investigation of at least one of the companies of the study and for a general background to the industry.
- Full Text:
- Date Issued: 1982
The impact of the identification process and the corporate social responsibility process on the effectiveness of multi-racial advertising in South Africa
- Authors: Johnson, Guillaume Desire
- Date: 2008
- Subjects: Marketing -- South Africa Advertising -- South Africa Sales promotion -- South Africa Consumers' preferences -- South Africa Marketing research -- South Africa Consumer behavior -- South Africa Consumption (Economics) -- Social aspect Attribution (Social psychology) South Africans -- Race identity Race awareness -- South Africa Ethnopsychology -- South Africa Group identity Racially mixed people
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1196 , http://hdl.handle.net/10962/d1008263
- Description: Selecting actors to appear in an advertisement is an important decision which has a crucial impact on the effectiveness of an advertising campaign. The same message, delivered by different actors, produces varying outcomes among consumers. This dilemma concerning the choice of actors occurs particularly in multi-racial societies, such as South Africa, where advertisers have to target different sectors of the community. In multi-racial societies, the choice of actors in advertisements goes beyond the usual commercial reasons. Indeed, two dimensions are generally conferred to multi-racial advertising. Firstly, the use of multi-racial representations allows for the targeting of a wider population that also owns a wider purchasing power. Marketers who want to market their brand use, for example, white and black actors so that white and black consumers can identify with the actors and recognize themselves as the target of the advertisement. Secondly, the multi-racial representations of this type of advertising hold a social role that counteracts the segregated depiction of the society. Consumers who are exposed to a multi-racial advertisement might perceive this social dimension and attribute a social responsibility to the advertisement. The purpose of this thesis is to examine the influence of the above dimensions on the effectiveness of a multi-racial advertisement. On the one hand, this study investigates the Identification Process followed by a consumer exposed to a multi-racial advertisement. On the other hand, it examines how consumers attribute a social responsibility to a specific multiracial advertisement and how this attribution, in turn, influences their responses to the advertisement and brand. Finally, the impacts of both of these dimensions on consumer behaviour are compared and the most persuasive dimension is identified. This thesis draws on Attribution Theory and Identification Theory in arguing that there are strong economic imperatives for adopting a multi-racial advertising approach. The thesis develops a conceptual framework and tests empirically hypotheses regarding the key constructs and moderating variables. The empirical results point out that both dimensions symbiotically influence the effectiveness of a multi-racial advertisement. Specifically, the results highlight that the social responsibility attributed by the viewers to the advertisement influences their behaviour more than the Identification Process.
- Full Text:
- Date Issued: 2008
- Authors: Johnson, Guillaume Desire
- Date: 2008
- Subjects: Marketing -- South Africa Advertising -- South Africa Sales promotion -- South Africa Consumers' preferences -- South Africa Marketing research -- South Africa Consumer behavior -- South Africa Consumption (Economics) -- Social aspect Attribution (Social psychology) South Africans -- Race identity Race awareness -- South Africa Ethnopsychology -- South Africa Group identity Racially mixed people
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1196 , http://hdl.handle.net/10962/d1008263
- Description: Selecting actors to appear in an advertisement is an important decision which has a crucial impact on the effectiveness of an advertising campaign. The same message, delivered by different actors, produces varying outcomes among consumers. This dilemma concerning the choice of actors occurs particularly in multi-racial societies, such as South Africa, where advertisers have to target different sectors of the community. In multi-racial societies, the choice of actors in advertisements goes beyond the usual commercial reasons. Indeed, two dimensions are generally conferred to multi-racial advertising. Firstly, the use of multi-racial representations allows for the targeting of a wider population that also owns a wider purchasing power. Marketers who want to market their brand use, for example, white and black actors so that white and black consumers can identify with the actors and recognize themselves as the target of the advertisement. Secondly, the multi-racial representations of this type of advertising hold a social role that counteracts the segregated depiction of the society. Consumers who are exposed to a multi-racial advertisement might perceive this social dimension and attribute a social responsibility to the advertisement. The purpose of this thesis is to examine the influence of the above dimensions on the effectiveness of a multi-racial advertisement. On the one hand, this study investigates the Identification Process followed by a consumer exposed to a multi-racial advertisement. On the other hand, it examines how consumers attribute a social responsibility to a specific multiracial advertisement and how this attribution, in turn, influences their responses to the advertisement and brand. Finally, the impacts of both of these dimensions on consumer behaviour are compared and the most persuasive dimension is identified. This thesis draws on Attribution Theory and Identification Theory in arguing that there are strong economic imperatives for adopting a multi-racial advertising approach. The thesis develops a conceptual framework and tests empirically hypotheses regarding the key constructs and moderating variables. The empirical results point out that both dimensions symbiotically influence the effectiveness of a multi-racial advertisement. Specifically, the results highlight that the social responsibility attributed by the viewers to the advertisement influences their behaviour more than the Identification Process.
- Full Text:
- Date Issued: 2008
Using reading to learn pedagogy to enhance the English first additional language teachers’ classroom practice
- Authors: Mawela, Rethabile Rejoice
- Date: 2018
- Subjects: Reading to learn , Language transfer (Language learning) -- South Africa -- Kuruman , Language teachers -- South Africa -- Kuruman , Language and languages -- Study and teaching -- Bilingual method , Second language acquisition
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63415 , vital:28409
- Description: Drawing from the Hallidayan, Bernsteinian and Vygotskyan theories of Systemic Functional Linguistics, Pedagogic Discourse and Social Learning, this study examined the role that Rose's (2005) Reading to Learn (RtL) pedagogy could play in the development of teachers’ pedagogic practices in the teaching of English First Additional Language. The study participants teach English First Additional Language in Black, materially and economically disadvantaged rural primary schools in Kuruman, the Northern Cape Province, South Africa. As study participants, 4 intermediate phase and 4 senior phase teachers of English First Additional Language were purposively selected from 6 rural schools. Located within the Critical Paradigm, Subjective Epistemology and Mixed-Method approach, the study used documentary evidence, semi- structured interviews and RtL pedagogy as research instruments. Research findings reveal that RtL enriched and advanced teachers’ pedagogic practice in the teaching of reading and writing. As a consequence, teachers’ classroom practice of the 8 study participants improved as evidenced as their content knowledge expanded, the quality of teaching developed and their perceptions of themselves as professionals was transformed. An accompanying finding is that teachers acquired the tools to teach reading and the reading and writing proficiencies of learners in their classrooms improved.
- Full Text:
- Date Issued: 2018
- Authors: Mawela, Rethabile Rejoice
- Date: 2018
- Subjects: Reading to learn , Language transfer (Language learning) -- South Africa -- Kuruman , Language teachers -- South Africa -- Kuruman , Language and languages -- Study and teaching -- Bilingual method , Second language acquisition
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63415 , vital:28409
- Description: Drawing from the Hallidayan, Bernsteinian and Vygotskyan theories of Systemic Functional Linguistics, Pedagogic Discourse and Social Learning, this study examined the role that Rose's (2005) Reading to Learn (RtL) pedagogy could play in the development of teachers’ pedagogic practices in the teaching of English First Additional Language. The study participants teach English First Additional Language in Black, materially and economically disadvantaged rural primary schools in Kuruman, the Northern Cape Province, South Africa. As study participants, 4 intermediate phase and 4 senior phase teachers of English First Additional Language were purposively selected from 6 rural schools. Located within the Critical Paradigm, Subjective Epistemology and Mixed-Method approach, the study used documentary evidence, semi- structured interviews and RtL pedagogy as research instruments. Research findings reveal that RtL enriched and advanced teachers’ pedagogic practice in the teaching of reading and writing. As a consequence, teachers’ classroom practice of the 8 study participants improved as evidenced as their content knowledge expanded, the quality of teaching developed and their perceptions of themselves as professionals was transformed. An accompanying finding is that teachers acquired the tools to teach reading and the reading and writing proficiencies of learners in their classrooms improved.
- Full Text:
- Date Issued: 2018
Gold nanoparticle–based colorimetric probes for dopamine detection
- Authors: Ngomane, Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4565 , http://hdl.handle.net/10962/d1021261
- Description: Colorimetric probes have become important tools in analysis and biomedical technology. This thesis reports on the development of such probes for the detection of dopamine (DA). Liquid and different solid state probes were developed utilizing un–functionalized gold nanoparticles (UF–AuNPs). The liquid state probe is based on the growth and aggregation of the UF–AuNPs in the presence of DA. Upon addition of the UF–AuNPs to various concentrations of DA, the shape, size and colour change results in spectral shifts from lower to higher wavelengths. The analyte can be easily monitored by the naked eye from 5.0 nM DA with a calculated limit of detection of 2.5 nM (3σ) under optimal pH. Ascorbic acid (AA) has a potential to interfere with DA detection in solution since it is often present in biological fluids, but in this case the interference was limited to solutions where its concentration was beyond 200 times greater than that of DA. Since most of the previously reported colorimetric probes, especially those for DA are solution based, the main focus of the thesis was in the development of a solid state based colorimetric probe in the form of nanofibre mats. To overcome the interference challenges experienced in the solution studies (the interference by high concentrations of AA), the suitability of molecularly imprinted polymers (MIPs) for the selective detection of DA was investigated. The results showed that the MIPs produced did not play a significant role in enhancing the selectivity towards DA. A probe composed of just the UF–AuNPs and Nylon–6 (UF–AuNPs + N6) was also developed. The UF–AuNPs were synthesized following an in situ reduction method. The probe was only selective to DA and insensitive to other catecholamines at physiological pH. Thus, the probe did not require any addition functionalities to achieve selectivity and sensitive to DA. The liquid state probe and the composite UF–AuNPs + N6 nanofibre probe were successfully applied to a whole blood sample and showed good selectivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on–site and immediate detection of DA without the use of instrumentation. For quantification of DA using the solid state probe, open–source software imageJ was used to assist in the analysis of the nanofibre colours. It was observed that the intensity of the colour increased with the increase in concentration of DA in a linear fashion. The use of imageJ can also be a great alternative where the colour changes are not so clear or for visually impaired people. The solid state probe developed can detect DA qualitatively and quantitatively. The work also forms a good foundation for development of such probes for other analyte.
- Full Text:
- Date Issued: 2016
- Authors: Ngomane, Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4565 , http://hdl.handle.net/10962/d1021261
- Description: Colorimetric probes have become important tools in analysis and biomedical technology. This thesis reports on the development of such probes for the detection of dopamine (DA). Liquid and different solid state probes were developed utilizing un–functionalized gold nanoparticles (UF–AuNPs). The liquid state probe is based on the growth and aggregation of the UF–AuNPs in the presence of DA. Upon addition of the UF–AuNPs to various concentrations of DA, the shape, size and colour change results in spectral shifts from lower to higher wavelengths. The analyte can be easily monitored by the naked eye from 5.0 nM DA with a calculated limit of detection of 2.5 nM (3σ) under optimal pH. Ascorbic acid (AA) has a potential to interfere with DA detection in solution since it is often present in biological fluids, but in this case the interference was limited to solutions where its concentration was beyond 200 times greater than that of DA. Since most of the previously reported colorimetric probes, especially those for DA are solution based, the main focus of the thesis was in the development of a solid state based colorimetric probe in the form of nanofibre mats. To overcome the interference challenges experienced in the solution studies (the interference by high concentrations of AA), the suitability of molecularly imprinted polymers (MIPs) for the selective detection of DA was investigated. The results showed that the MIPs produced did not play a significant role in enhancing the selectivity towards DA. A probe composed of just the UF–AuNPs and Nylon–6 (UF–AuNPs + N6) was also developed. The UF–AuNPs were synthesized following an in situ reduction method. The probe was only selective to DA and insensitive to other catecholamines at physiological pH. Thus, the probe did not require any addition functionalities to achieve selectivity and sensitive to DA. The liquid state probe and the composite UF–AuNPs + N6 nanofibre probe were successfully applied to a whole blood sample and showed good selectivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on–site and immediate detection of DA without the use of instrumentation. For quantification of DA using the solid state probe, open–source software imageJ was used to assist in the analysis of the nanofibre colours. It was observed that the intensity of the colour increased with the increase in concentration of DA in a linear fashion. The use of imageJ can also be a great alternative where the colour changes are not so clear or for visually impaired people. The solid state probe developed can detect DA qualitatively and quantitatively. The work also forms a good foundation for development of such probes for other analyte.
- Full Text:
- Date Issued: 2016
Comprehending strike action: the South African experience c.1950-1990 and the theoretical implications thereof
- Authors: Wood, Geoffrey Thomas
- Date: 1995
- Subjects: Strikes and lockouts -- South Africa -- History Industrial relations -- South Africa -- History Labor unions -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3319 , http://hdl.handle.net/10962/d1003107
- Description: Regular strike action has become a central characteristic of the South African industrial relations system. Whilst in the 1950s strikes were mostly isolated outbursts of relatively short duration, strikes in the 1980s were challenges of unprecedented duration and intensity. It is argued that despite this dramatic change, reflecting a series of discontinuities in both the political and economic arenas, strike action in South Africa does follow distinct patterns, and can be ascribed to a combination of identifiable causes. Principal causal factors include wage aspirations, past experiences and the subjective interpretation thereof, and the role of the union movement. Contingent factors include the prevailing political climate, industrial relations legislation, the amount of information opposing sides possess of their adversaries' intentions as well as spatial issues, such as the internal dynamics of individual communities. Partially as a result of South Africa's political transformation, the late 1980s and early 1990s saw further changes in the industrial relations environment. Reflecting these developments, it is argued that a new type of trade unionism has developed, "coterminous unionism" . This will have far-reaching implications for the nature of industrial conflict. However, it falls fully within the theoretical parameters outlined in this thesis. Despite significant developments in social theory in the 1980s and 1990s, there have been few attempts accordingly to update theories of strike action. One of the objectives of this thesis has been to attempt such an update. It is hoped that the constructs developed will shed light on a widely prevalent form of social conflict, assist in the analysis of future outbreaks, and enable the identification of those situations where a high propensity to engage in strike action may exist.
- Full Text:
- Date Issued: 1995
- Authors: Wood, Geoffrey Thomas
- Date: 1995
- Subjects: Strikes and lockouts -- South Africa -- History Industrial relations -- South Africa -- History Labor unions -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3319 , http://hdl.handle.net/10962/d1003107
- Description: Regular strike action has become a central characteristic of the South African industrial relations system. Whilst in the 1950s strikes were mostly isolated outbursts of relatively short duration, strikes in the 1980s were challenges of unprecedented duration and intensity. It is argued that despite this dramatic change, reflecting a series of discontinuities in both the political and economic arenas, strike action in South Africa does follow distinct patterns, and can be ascribed to a combination of identifiable causes. Principal causal factors include wage aspirations, past experiences and the subjective interpretation thereof, and the role of the union movement. Contingent factors include the prevailing political climate, industrial relations legislation, the amount of information opposing sides possess of their adversaries' intentions as well as spatial issues, such as the internal dynamics of individual communities. Partially as a result of South Africa's political transformation, the late 1980s and early 1990s saw further changes in the industrial relations environment. Reflecting these developments, it is argued that a new type of trade unionism has developed, "coterminous unionism" . This will have far-reaching implications for the nature of industrial conflict. However, it falls fully within the theoretical parameters outlined in this thesis. Despite significant developments in social theory in the 1980s and 1990s, there have been few attempts accordingly to update theories of strike action. One of the objectives of this thesis has been to attempt such an update. It is hoped that the constructs developed will shed light on a widely prevalent form of social conflict, assist in the analysis of future outbreaks, and enable the identification of those situations where a high propensity to engage in strike action may exist.
- Full Text:
- Date Issued: 1995
An analysis of how the Senior Certificate examination constructs the language needs of English second language learners
- Authors: Blunt, Sandra Viki
- Date: 2006 , 2013-06-11
- Subjects: Habermas, Jürgen Education, Secondary -- South Africa Examinations -- South Africa -- Evaluation English language -- Examinations -- South Africa English language -- Study and teaching -- South Africa -- Foreign speakers Language and education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1902 , http://hdl.handle.net/10962/d1006243
- Description: The Senior Certificate (SC) examination, a focus of the research described in this thesis, has an important function in terms of the quality of the education system overall and also in terms of the contribution of education to the achievement of national goals. The SC examination functions i) as a measure of achievement at school ii) as an indicator of work readiness and iii) as an indicator of the potential to succeed in higher education. This thesis offers a critique of the SC examination in respect of its functions. The way in which learners' language related needs are constructed is crucial in discussing the SC examination's legitimacy since perceptions about the needs of learners are reflected in what is taught and assessed. Since the majority of candidates writing the SC exarnination do so using a language which is not their mother tongue, the research described in the thesis attempted to identify the way in which the English second language (ESL) SC examination papers construct learners' needs. Examination papers represent a particular domain of social practice and are constructed through discourse. In the context of the research described in this thesis, discourses are understood as sets of ideas which are shared by communities of people and which give rise to practices which then define and sustain those communities and, thus, the discourses themselves. Discourse is language insofar as it converges with power and positions people in the interests of power. The ideological nature of discourse necessitates a critical orientation to research which interrogates, challenges and critiques the status quo. To identify the discourses constructing ESL learners' needs I conducted a critical discourse analysis on a representative sarnple of ESL SC exarnination papers and also interviewed six ESL examiners to corroborate the findings of the analysis. This then allowed me to identify several dominant discourses constructing ESL learners' needs: meaning-related, literature-related and process-related. The first meaning-related discourse, 'Received Tradition' discourse, focuses on the rules of grammar and spelling. Rather than approaching language as a resource to enable learners to understand the ideas to which they are exposed, learners are being taught discrete 'skills' to equip them for higher education study and the workplace. It is argued that school-based language literacy practices are not generalizable to the workplace and to higher education. Another aspect of 'Received Tradition' discourse holds that the study of English literature is a medium for understanding life and that there is moral value in teaching English literature. Learners are therefore constructed as lacking these values and their needs as having to acquire them. 'Received Tradition' discourse also overlaps with a second meaning-related discourse, 'Autonomous Text' discourse, which holds that the text's meaning is explicit and that if the learners can manipulate the rules of English grammar, 'have' vocabulary and can spell, they can retrieve meanings from texts they encounter in a wide range of contexts and construct texts for themselves. It is argued that a lack of awareness that meaning is constructed through recourse to other contexts, texts and the learner's experience is disadvantaging ESL candidates. 'Language as an Instrument of Communication' discourse, the last meaning-related discourse identified, sees language as the vehicle used to convey ideas, thoughts, information and beliefs, which are viewed as having been constructed independently of language. It is assumed that the answers, which, according to 'Autonomous Text' discourse, are in the text, can be conveyed if the tools of language are used correctly. The first literature-related discourse identified is 'Literature Study Develops Language Proficiency'. It is argued this is a misperception since language is learned as part of situated practice and instruction must thus be embedded in meaningful communicative contexts involving situated practice. The second literature-related discourse identified, 'Literature Study is a Medium for Understanding Life', is connected to the 'Received Tradition' discourse referred to above which holds that there is moral value in teaching English literature. This research identifies the ideological implications of these discourses, arguing that values are culture-specific and learners from diverse socio-cultural backgrounds experience life differently from the way it is depicted in English literature. Process-related discourses, which are part of the processes of teaching and assessment, concern the inadequacy of the ESL learner and of the markers and therefore dictate what can and cannot be expected of ESL learners in the SC examination. The research showed how all of the above discourses work through the SC curriculum to impose the values and beliefs of particular dominant groups on the ESL learner. Because of the robust and invidious nature of discourses this is a cause for concern. Although it is difficult to set a school leaving examination which serves both workplace and academic functions, there is a need to move beyond traditional, hegemonic approaches to understanding language learning. This thesis offers an analysis which can be used to inform practice.
- Full Text:
- Date Issued: 2006
- Authors: Blunt, Sandra Viki
- Date: 2006 , 2013-06-11
- Subjects: Habermas, Jürgen Education, Secondary -- South Africa Examinations -- South Africa -- Evaluation English language -- Examinations -- South Africa English language -- Study and teaching -- South Africa -- Foreign speakers Language and education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1902 , http://hdl.handle.net/10962/d1006243
- Description: The Senior Certificate (SC) examination, a focus of the research described in this thesis, has an important function in terms of the quality of the education system overall and also in terms of the contribution of education to the achievement of national goals. The SC examination functions i) as a measure of achievement at school ii) as an indicator of work readiness and iii) as an indicator of the potential to succeed in higher education. This thesis offers a critique of the SC examination in respect of its functions. The way in which learners' language related needs are constructed is crucial in discussing the SC examination's legitimacy since perceptions about the needs of learners are reflected in what is taught and assessed. Since the majority of candidates writing the SC exarnination do so using a language which is not their mother tongue, the research described in the thesis attempted to identify the way in which the English second language (ESL) SC examination papers construct learners' needs. Examination papers represent a particular domain of social practice and are constructed through discourse. In the context of the research described in this thesis, discourses are understood as sets of ideas which are shared by communities of people and which give rise to practices which then define and sustain those communities and, thus, the discourses themselves. Discourse is language insofar as it converges with power and positions people in the interests of power. The ideological nature of discourse necessitates a critical orientation to research which interrogates, challenges and critiques the status quo. To identify the discourses constructing ESL learners' needs I conducted a critical discourse analysis on a representative sarnple of ESL SC exarnination papers and also interviewed six ESL examiners to corroborate the findings of the analysis. This then allowed me to identify several dominant discourses constructing ESL learners' needs: meaning-related, literature-related and process-related. The first meaning-related discourse, 'Received Tradition' discourse, focuses on the rules of grammar and spelling. Rather than approaching language as a resource to enable learners to understand the ideas to which they are exposed, learners are being taught discrete 'skills' to equip them for higher education study and the workplace. It is argued that school-based language literacy practices are not generalizable to the workplace and to higher education. Another aspect of 'Received Tradition' discourse holds that the study of English literature is a medium for understanding life and that there is moral value in teaching English literature. Learners are therefore constructed as lacking these values and their needs as having to acquire them. 'Received Tradition' discourse also overlaps with a second meaning-related discourse, 'Autonomous Text' discourse, which holds that the text's meaning is explicit and that if the learners can manipulate the rules of English grammar, 'have' vocabulary and can spell, they can retrieve meanings from texts they encounter in a wide range of contexts and construct texts for themselves. It is argued that a lack of awareness that meaning is constructed through recourse to other contexts, texts and the learner's experience is disadvantaging ESL candidates. 'Language as an Instrument of Communication' discourse, the last meaning-related discourse identified, sees language as the vehicle used to convey ideas, thoughts, information and beliefs, which are viewed as having been constructed independently of language. It is assumed that the answers, which, according to 'Autonomous Text' discourse, are in the text, can be conveyed if the tools of language are used correctly. The first literature-related discourse identified is 'Literature Study Develops Language Proficiency'. It is argued this is a misperception since language is learned as part of situated practice and instruction must thus be embedded in meaningful communicative contexts involving situated practice. The second literature-related discourse identified, 'Literature Study is a Medium for Understanding Life', is connected to the 'Received Tradition' discourse referred to above which holds that there is moral value in teaching English literature. This research identifies the ideological implications of these discourses, arguing that values are culture-specific and learners from diverse socio-cultural backgrounds experience life differently from the way it is depicted in English literature. Process-related discourses, which are part of the processes of teaching and assessment, concern the inadequacy of the ESL learner and of the markers and therefore dictate what can and cannot be expected of ESL learners in the SC examination. The research showed how all of the above discourses work through the SC curriculum to impose the values and beliefs of particular dominant groups on the ESL learner. Because of the robust and invidious nature of discourses this is a cause for concern. Although it is difficult to set a school leaving examination which serves both workplace and academic functions, there is a need to move beyond traditional, hegemonic approaches to understanding language learning. This thesis offers an analysis which can be used to inform practice.
- Full Text:
- Date Issued: 2006
Exploring functionings and conversion factors in biodiversity teacher professional learning communities
- Tshiningayamwe, Sirkka Alina Nambashun
- Authors: Tshiningayamwe, Sirkka Alina Nambashun
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2080 , http://hdl.handle.net/10962/d1021313
- Description: The study explores the conversion factors, functionings (valued beings and doings), agency and structures in Professional Learning Communities (PLCs) for Life Sciences teachers’ biodiversity knowledge. The teachers’ valued beings and doings as well as conversion factors associated with these beings and doings were discussed within the conceptual framework of the capability approach using three PLCs in South Africa. Two PLCs were in the Eastern Cape Province (Grahamstown and Idutywa district), and one PLC was in the Western Cape (Cape Town) province. The PLCs involved in this study were course initiated and were positioned in the Fundisa for Change national teacher education programme. Fundisa for Change is a partnership programme that aims to enhance transformative environmental learning through teacher education. To illuminate constrained capabilities and how and to what extent the Life Sciences teachers’ empirical actions are related to these, the concepts of the capability approach were underlaboured with critical realism’s causal view of human action. A critical realist theory of causation was useful in explaining how the teachers’ valued beings and doings, conversion factors and capability sets can be partly accounted for via an understanding of underlying mechanisms that are generative of events and empirical experience. The study used a qualitative case study research methodology. Interviews, questionnaires, observations (of PLC activities), document reviews (of teachers’ portfolios of evidence, Fundisa for Change implementation plan, evaluation forms and resources materials, and policy documents) and reflection tools were used to collect data. Using the critical realism modes of inference (induction, abduction and retroduction), the data was analysed in two phases. Phase one analysis was primarily inductive and used thick descriptions (mainly in the form of quotes) to present and discuss the teachers’ valued beings and doings and associated conversion factors in the PLCs. This phase of analysis was abductive. The study reported four main functionings valued by teachers: subject content knowledge, teaching practices, assessment practices, and use of teaching and learning support materials. These valued functionings were discussed in light of the beings and doings in the PLCs and the underlying mechanisms related to teachers’ biodiversity teaching. Conversion factors that were associated with the teachers’ valued beings and doings in the PLCs were discussed in line with capability approach’s environmental, social and personal conversion factors. The study found that most of the conversion factors within the PLCs and the Fundisa for Change professional development programme (good facilitation, collaborative learning space, site where PLC activities happened, individual teachers’ capabilities, teaching and learning support materials and policy documents) were enablers to the teachers’ capabilities for biodiversity teaching, and thus enhanced teachers’ knowledge for biodiversity teaching. The study further found that teachers realised some of their achieved functionings in their actual teaching of biodiversity content in the Life Sciences curriculum, and that factors such as lack of resources, large class sizes, learners’ abilities and lack of interest among some teachers were amongst the factors that constrained teachers’ realisation of their achieved functionings in the PLCs. The study therefore revealed that if professional development programmes take account of underlying mechanisms and respond to teachers’ capabilities i.e. their valued functionings for biodiversity teaching in the Life Sciences curriculum, the professional development programmes can be an important conversion factor that enables the expansion of teachers’ capabilities (especially their biodiversity knowledge, pedagogical and assessment practice but also other capabilities) in ways that have the potential to reshape teachers’ classroom practices related to the teaching of biodiversity.
- Full Text:
- Date Issued: 2016
- Authors: Tshiningayamwe, Sirkka Alina Nambashun
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2080 , http://hdl.handle.net/10962/d1021313
- Description: The study explores the conversion factors, functionings (valued beings and doings), agency and structures in Professional Learning Communities (PLCs) for Life Sciences teachers’ biodiversity knowledge. The teachers’ valued beings and doings as well as conversion factors associated with these beings and doings were discussed within the conceptual framework of the capability approach using three PLCs in South Africa. Two PLCs were in the Eastern Cape Province (Grahamstown and Idutywa district), and one PLC was in the Western Cape (Cape Town) province. The PLCs involved in this study were course initiated and were positioned in the Fundisa for Change national teacher education programme. Fundisa for Change is a partnership programme that aims to enhance transformative environmental learning through teacher education. To illuminate constrained capabilities and how and to what extent the Life Sciences teachers’ empirical actions are related to these, the concepts of the capability approach were underlaboured with critical realism’s causal view of human action. A critical realist theory of causation was useful in explaining how the teachers’ valued beings and doings, conversion factors and capability sets can be partly accounted for via an understanding of underlying mechanisms that are generative of events and empirical experience. The study used a qualitative case study research methodology. Interviews, questionnaires, observations (of PLC activities), document reviews (of teachers’ portfolios of evidence, Fundisa for Change implementation plan, evaluation forms and resources materials, and policy documents) and reflection tools were used to collect data. Using the critical realism modes of inference (induction, abduction and retroduction), the data was analysed in two phases. Phase one analysis was primarily inductive and used thick descriptions (mainly in the form of quotes) to present and discuss the teachers’ valued beings and doings and associated conversion factors in the PLCs. This phase of analysis was abductive. The study reported four main functionings valued by teachers: subject content knowledge, teaching practices, assessment practices, and use of teaching and learning support materials. These valued functionings were discussed in light of the beings and doings in the PLCs and the underlying mechanisms related to teachers’ biodiversity teaching. Conversion factors that were associated with the teachers’ valued beings and doings in the PLCs were discussed in line with capability approach’s environmental, social and personal conversion factors. The study found that most of the conversion factors within the PLCs and the Fundisa for Change professional development programme (good facilitation, collaborative learning space, site where PLC activities happened, individual teachers’ capabilities, teaching and learning support materials and policy documents) were enablers to the teachers’ capabilities for biodiversity teaching, and thus enhanced teachers’ knowledge for biodiversity teaching. The study further found that teachers realised some of their achieved functionings in their actual teaching of biodiversity content in the Life Sciences curriculum, and that factors such as lack of resources, large class sizes, learners’ abilities and lack of interest among some teachers were amongst the factors that constrained teachers’ realisation of their achieved functionings in the PLCs. The study therefore revealed that if professional development programmes take account of underlying mechanisms and respond to teachers’ capabilities i.e. their valued functionings for biodiversity teaching in the Life Sciences curriculum, the professional development programmes can be an important conversion factor that enables the expansion of teachers’ capabilities (especially their biodiversity knowledge, pedagogical and assessment practice but also other capabilities) in ways that have the potential to reshape teachers’ classroom practices related to the teaching of biodiversity.
- Full Text:
- Date Issued: 2016
Environmental policy processes surrounding South Africa's plastic bags regulations : tensions, debates and responses in waste product regulation
- Authors: Nhamo, Godwell
- Date: 2013-06-07
- Subjects: Environmental policy -- South Africa Plastic bags -- Law and legislation -- South Africa Environmental protection -- South Africa Environmental law -- South Africa Waste products -- South Africa Refuse and refuse disposal -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1944 , http://hdl.handle.net/10962/d1008051
- Description: This study was conducted in South Africa. South Africa is the first country within the Southern African Development Community to have regulated plastic shopping bags waste through the imposition of both a standard on thickness and a levy. Given this scenario, the Plastic Bags Regulations present an illustrative case for researching complexity, uncertainty and controversies surrounding a new trend in environmental policy making, namely waste product regulation. The thesis focuses on understanding and investigating tensions, debates and responses emerging from the policy process as actors and actor-networks put not only the Plastic Bags Regulations asfocal actant (token) but also other actants and actant-networks as well. To this end, a research question that addressed environmental policies, tensions, debates and responses that informed the development of South Africa's Plastic Bags Regulations was spelt out. The research objectives included the need to: (I) analyse selected international environmental policy processes surrounding plastic shopping bags litter and waste regulation and how these influenced developments in South Africa; (2) identify actors, actants and actor/actant-networks that shaped and were being transformed by South Africa's Plastic Bags Regulations and explain the tensions, debates and responses arising in the policy processes; (3) identify environmental policy outputs and assess outcomes emerging from the formulation and implementation of South Africa's Plastic Bags Regulations; and (4) establish patterns in environmental policy process reforms around South Africa's Plastic Bags Regulations. The language of actors (human), actants (non-human) and actor/actant-networks brings to the fore the aspects of processes and relationships that exist around them. As such, insights from the actor/actant-network theory (AANT) were drawn upon to inform the research. AANT enquiry framework collapses binaries such as nature/society, art/science, structure/agency and global/local historically associated with a particular type of social theory. AANT also denies that purely technical, scientific or social relations are possible (the notion of quaSi-objects or token). Data sets were generated following' the Plastic Bags Regulations as token actant with time frames ranging from prior to, during and after the formulation of the regulations. Similarly, data analysis drew insights from AANT's four moments of translation namely problematisation, interessement, enrolment and mobilisation, with the intervention theory providing an evaluative perspective that complemented AANT. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether command and control - preferred by government or self regulation - preferred by industry and labour). In this regard the latter group raised concerns about jobs, income and equipment loss as well as the need to have a holistic approach to waste management rather than targeting a single product at a time whilst the former maintained that this would not be so. As such, education, awareness and stringent antilitter penalties were proposed by industry and labour as sustainable responses to the problem of plastic shopping bags waste rather than regulation. These debates continued and resulted in minor amendments to the original regulations as finalised by Government in May 2002. However, industry and labour continued lobbying government resulting in the conclusion of the Plastic Bags Agreement in September 2002 and the ultimate repulsion of the May 2002 regulations in May 2003. As revealed by this research, these responses led to broader social responses and further tensions as demand for plastic shopping bags went down by about 80% although an estimated 1000 jobs were lost and a number of companies lost equipment and business (with some closing down) following the implementation of the regulations. During implementation, debates emerged around the need to promote locally made carry facilities with two alternatives in sight namely: the Green Bag and the Biodegradable Plastic Bag. Debates also took place regarding enforcement of the new law resulting in the amendments of various pieces of legislation including the Environmental Conservation Act, Environmental Management Act and the Revenue Laws Act. Overall, a 15-year policy reform cycle and sub-cycles was determined. The research also established that the government considered the regulations a success and was already implementing simi lar initiatives to regulate other waste products, among them, used tyres, used oil and glass, confirming the trend towards waste product regulation in South Africa. From these research findings, a series of conceptual frameworks were drawn up to clarify the nature of tensions, debates and responses surrounding certain lead actors, actants and actorlactant-networks. Some of the conceptual frameworks that emerged around the actors and actor-networks include Organised Government, Organised Industry and Organised Labour. Conceptual frameworks that emerged around key actants and actant-networks include the Integrated Pollution and Waste Management, Plastic Bags Regulations as well as the discourses surrounding the Green bag and biodegradable plastic bags. The thesis concludes by reflecting on how the above and the grand actor/actant-network conceptual frameworks emerging from this research might be adopted with varying degrees of flexibility to research environmental and waste management policy processes in different waste product regulation set-ups. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Nhamo, Godwell
- Date: 2013-06-07
- Subjects: Environmental policy -- South Africa Plastic bags -- Law and legislation -- South Africa Environmental protection -- South Africa Environmental law -- South Africa Waste products -- South Africa Refuse and refuse disposal -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1944 , http://hdl.handle.net/10962/d1008051
- Description: This study was conducted in South Africa. South Africa is the first country within the Southern African Development Community to have regulated plastic shopping bags waste through the imposition of both a standard on thickness and a levy. Given this scenario, the Plastic Bags Regulations present an illustrative case for researching complexity, uncertainty and controversies surrounding a new trend in environmental policy making, namely waste product regulation. The thesis focuses on understanding and investigating tensions, debates and responses emerging from the policy process as actors and actor-networks put not only the Plastic Bags Regulations asfocal actant (token) but also other actants and actant-networks as well. To this end, a research question that addressed environmental policies, tensions, debates and responses that informed the development of South Africa's Plastic Bags Regulations was spelt out. The research objectives included the need to: (I) analyse selected international environmental policy processes surrounding plastic shopping bags litter and waste regulation and how these influenced developments in South Africa; (2) identify actors, actants and actor/actant-networks that shaped and were being transformed by South Africa's Plastic Bags Regulations and explain the tensions, debates and responses arising in the policy processes; (3) identify environmental policy outputs and assess outcomes emerging from the formulation and implementation of South Africa's Plastic Bags Regulations; and (4) establish patterns in environmental policy process reforms around South Africa's Plastic Bags Regulations. The language of actors (human), actants (non-human) and actor/actant-networks brings to the fore the aspects of processes and relationships that exist around them. As such, insights from the actor/actant-network theory (AANT) were drawn upon to inform the research. AANT enquiry framework collapses binaries such as nature/society, art/science, structure/agency and global/local historically associated with a particular type of social theory. AANT also denies that purely technical, scientific or social relations are possible (the notion of quaSi-objects or token). Data sets were generated following' the Plastic Bags Regulations as token actant with time frames ranging from prior to, during and after the formulation of the regulations. Similarly, data analysis drew insights from AANT's four moments of translation namely problematisation, interessement, enrolment and mobilisation, with the intervention theory providing an evaluative perspective that complemented AANT. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether command and control - preferred by government or self regulation - preferred by industry and labour). In this regard the latter group raised concerns about jobs, income and equipment loss as well as the need to have a holistic approach to waste management rather than targeting a single product at a time whilst the former maintained that this would not be so. As such, education, awareness and stringent antilitter penalties were proposed by industry and labour as sustainable responses to the problem of plastic shopping bags waste rather than regulation. These debates continued and resulted in minor amendments to the original regulations as finalised by Government in May 2002. However, industry and labour continued lobbying government resulting in the conclusion of the Plastic Bags Agreement in September 2002 and the ultimate repulsion of the May 2002 regulations in May 2003. As revealed by this research, these responses led to broader social responses and further tensions as demand for plastic shopping bags went down by about 80% although an estimated 1000 jobs were lost and a number of companies lost equipment and business (with some closing down) following the implementation of the regulations. During implementation, debates emerged around the need to promote locally made carry facilities with two alternatives in sight namely: the Green Bag and the Biodegradable Plastic Bag. Debates also took place regarding enforcement of the new law resulting in the amendments of various pieces of legislation including the Environmental Conservation Act, Environmental Management Act and the Revenue Laws Act. Overall, a 15-year policy reform cycle and sub-cycles was determined. The research also established that the government considered the regulations a success and was already implementing simi lar initiatives to regulate other waste products, among them, used tyres, used oil and glass, confirming the trend towards waste product regulation in South Africa. From these research findings, a series of conceptual frameworks were drawn up to clarify the nature of tensions, debates and responses surrounding certain lead actors, actants and actorlactant-networks. Some of the conceptual frameworks that emerged around the actors and actor-networks include Organised Government, Organised Industry and Organised Labour. Conceptual frameworks that emerged around key actants and actant-networks include the Integrated Pollution and Waste Management, Plastic Bags Regulations as well as the discourses surrounding the Green bag and biodegradable plastic bags. The thesis concludes by reflecting on how the above and the grand actor/actant-network conceptual frameworks emerging from this research might be adopted with varying degrees of flexibility to research environmental and waste management policy processes in different waste product regulation set-ups. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
Aspects of prostacyclin in experimental hypertension
- Authors: Botha, Julia Hilary
- Date: 1983
- Subjects: Prostacyclin Prostaglandins Prostaglandin endoperoxides Thromboxanes Hypertension
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3825 , http://hdl.handle.net/10962/d1006109
- Description: A new prostaglandin - prostaglandin X (later renamed prostacyclin or prostaglandin I₂ (PGI₂)), was discovered by Moncada, Gryglewski, Bunting and Vane in 1976. This unstable substance was shown to be produced by vascular tissue and to be a vasodilator and the most potent endogenous inhibitor of platelet aggregation known. Because of its properties, it appeared that a lack of it may be related to the development and or maintenance of hypertension, a disorder featuring vasoconstriction and an increased tendency to arterial thrombosis. The present studies aimed to investigate this possibility using a rat model. A bioassay for prostacyclin was first perfected. This consisted of a modification of the method used by Moncada, Higgs and Vane (1977): PGI₂ released by rat aortic strips, during incubation in tris buffer, was measured by assessing the ability of the incubate to inhibit adenosine diphosphate induced aggregation of human platelets, as compared to the inhibitory effect of standard prostacyclin sodium salt. The specificity of the assay for the detection of PGI₂ was tested. The abil ity of hypertensive rat aorta to release prostacycl in was investigated in two studies. The first compared aortas of Wistar rats of the New Zealand genetically hypertensive strain (GH) with those of matched normotensive Wistar controls. In the second study, hypertension was induced by wrappi ng the ri ght kidney with surgical silk and removing the contralateral kidney. Ten weeks later, aortic generation of prostacyclin by these animals was compared with that of matched sham controls which had received identical surgical manipulation but for the application of silk to the right kidney. Contrary to expectation, in both forms of hypertension, aortas of the rats with elevated pressure produced consistently more prostacyclin than those of matched controls. In order to discover more about the relationship between elevated pressure and elevated PGI₂ production, the effect of pressure reduction with hypotensive agents on the ability of GH rat aortas to produce prostacyclin, was investigated. After pressure had been controlled within normal range for one week (achieved by oral administration of furosemide, dihydralazine and reserpine for one month), aortic PGI₂ was reduced in comparison with matched GH controls. However, the reduction was not consistent and statistical significance was not reached. Because it was subsequently reported by other workers, that some of the hypotensive agents which had been employed may effect prostaglandin levels per se, no conclusions could be drawn from this study as to any possible direct relationships between pressure and aortic prostacyclin generating capacity. A further means of reducing elevated pressure (which had no inherent effect on prostaglandin levels) was thus sought. A mechanical method was eventually selected, application of a silver clip to the aortas of GH rats, just below the diaphragm, producing an immediate reduction in pressure distal to the constriction. Eighteen hours with later, PGI₂ production by these distal aortas those of matched sham GH controls and was was compared found to be consistently reduced. These results indicate that the ability to produce PGI₂ may be influenced by prior local pressure changes and that the increased capacity of hypertensive rat aortas to generate prostacyclin may be related to the increased mechanical transmural stress consequent on elevated pressure. Since haemostatic balance must be influenced not only by vascular PGI₂ generation but also by platelet sensitivity to PGI₂, the response of GH platelets to the anti-aggregatory effect of prostacyc1in was also investigated. As it had been shown by Sinzinger, Si1berbauer, Horsch and Gall (1981) that intra-arterial infusion of PGI₂ in humans decreased platelet sensitivity to the substance, the possibility existed that platelet sensitivity in hypertension might be reduced. This hypothesis was, however, invalidated as the sensitivity of GH platelets to the anti-aggregatory effect of PGI₂ was almost identical to that of normotensive controls. The shortcomings of the methodology and the possible importance of these findings in the hypertensive animal are discussed. The idea that elevated PGI₂ in hypertension may play a protective role both with respect to platelet aggregation and in attenuating further pressure rises is considered. It is finally suggested that it will be possible to draw more accurate conclusions as to the meaning of the increased PGI₂ generation in hypertension (both in relation to vascular tone and platelet function) only when details of production of, and sensitivity to, thromboxane A₂ are known. Thromboxane A₂ (TXA₂) is a vasoconstrictor and promotor of aggregation (Hamberg, Svensson and Samuelson, 1975) and it may be that, despite elevated vascular PGI₂ generation, the TXA₂/PGI₂ balance is still tipped in favour of vasoconstriction and platelet aggregation in hypertension.
- Full Text:
- Date Issued: 1983
- Authors: Botha, Julia Hilary
- Date: 1983
- Subjects: Prostacyclin Prostaglandins Prostaglandin endoperoxides Thromboxanes Hypertension
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3825 , http://hdl.handle.net/10962/d1006109
- Description: A new prostaglandin - prostaglandin X (later renamed prostacyclin or prostaglandin I₂ (PGI₂)), was discovered by Moncada, Gryglewski, Bunting and Vane in 1976. This unstable substance was shown to be produced by vascular tissue and to be a vasodilator and the most potent endogenous inhibitor of platelet aggregation known. Because of its properties, it appeared that a lack of it may be related to the development and or maintenance of hypertension, a disorder featuring vasoconstriction and an increased tendency to arterial thrombosis. The present studies aimed to investigate this possibility using a rat model. A bioassay for prostacyclin was first perfected. This consisted of a modification of the method used by Moncada, Higgs and Vane (1977): PGI₂ released by rat aortic strips, during incubation in tris buffer, was measured by assessing the ability of the incubate to inhibit adenosine diphosphate induced aggregation of human platelets, as compared to the inhibitory effect of standard prostacyclin sodium salt. The specificity of the assay for the detection of PGI₂ was tested. The abil ity of hypertensive rat aorta to release prostacycl in was investigated in two studies. The first compared aortas of Wistar rats of the New Zealand genetically hypertensive strain (GH) with those of matched normotensive Wistar controls. In the second study, hypertension was induced by wrappi ng the ri ght kidney with surgical silk and removing the contralateral kidney. Ten weeks later, aortic generation of prostacyclin by these animals was compared with that of matched sham controls which had received identical surgical manipulation but for the application of silk to the right kidney. Contrary to expectation, in both forms of hypertension, aortas of the rats with elevated pressure produced consistently more prostacyclin than those of matched controls. In order to discover more about the relationship between elevated pressure and elevated PGI₂ production, the effect of pressure reduction with hypotensive agents on the ability of GH rat aortas to produce prostacyclin, was investigated. After pressure had been controlled within normal range for one week (achieved by oral administration of furosemide, dihydralazine and reserpine for one month), aortic PGI₂ was reduced in comparison with matched GH controls. However, the reduction was not consistent and statistical significance was not reached. Because it was subsequently reported by other workers, that some of the hypotensive agents which had been employed may effect prostaglandin levels per se, no conclusions could be drawn from this study as to any possible direct relationships between pressure and aortic prostacyclin generating capacity. A further means of reducing elevated pressure (which had no inherent effect on prostaglandin levels) was thus sought. A mechanical method was eventually selected, application of a silver clip to the aortas of GH rats, just below the diaphragm, producing an immediate reduction in pressure distal to the constriction. Eighteen hours with later, PGI₂ production by these distal aortas those of matched sham GH controls and was was compared found to be consistently reduced. These results indicate that the ability to produce PGI₂ may be influenced by prior local pressure changes and that the increased capacity of hypertensive rat aortas to generate prostacyclin may be related to the increased mechanical transmural stress consequent on elevated pressure. Since haemostatic balance must be influenced not only by vascular PGI₂ generation but also by platelet sensitivity to PGI₂, the response of GH platelets to the anti-aggregatory effect of prostacyc1in was also investigated. As it had been shown by Sinzinger, Si1berbauer, Horsch and Gall (1981) that intra-arterial infusion of PGI₂ in humans decreased platelet sensitivity to the substance, the possibility existed that platelet sensitivity in hypertension might be reduced. This hypothesis was, however, invalidated as the sensitivity of GH platelets to the anti-aggregatory effect of PGI₂ was almost identical to that of normotensive controls. The shortcomings of the methodology and the possible importance of these findings in the hypertensive animal are discussed. The idea that elevated PGI₂ in hypertension may play a protective role both with respect to platelet aggregation and in attenuating further pressure rises is considered. It is finally suggested that it will be possible to draw more accurate conclusions as to the meaning of the increased PGI₂ generation in hypertension (both in relation to vascular tone and platelet function) only when details of production of, and sensitivity to, thromboxane A₂ are known. Thromboxane A₂ (TXA₂) is a vasoconstrictor and promotor of aggregation (Hamberg, Svensson and Samuelson, 1975) and it may be that, despite elevated vascular PGI₂ generation, the TXA₂/PGI₂ balance is still tipped in favour of vasoconstriction and platelet aggregation in hypertension.
- Full Text:
- Date Issued: 1983
Family diversity : a South African perspective focusing on Whites in Grahamstown
- Authors: Ziehl, Susan C
- Date: 1998
- Subjects: Families -- History -- Research Families -- South Africa -- Grahamstown Families Families -- Research -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3341 , http://hdl.handle.net/10962/d1004467
- Description: Drawing on developments in the field of family history and studies of families in contemporary settings, the study addresses the question of explaining variations in household patterns. Its empirical basis is a survey of White households in Grahamstown. The surveyed population was broken down in terms of class (occupation) and culture (language) and analyses conducted to determine if there are any statistically significant relationships between these variables and the tendency to reside in particular household structures. The question of 'family ideology' was also addressed as an attempt was made to uncover subjects' views on a variety of family-related issues. On the basis of the research results, a model of the relationship between class, culture and household structure was developed. Its application to a comparison of Black and White household structures in South Africa as well as the United States, is discussed. Finally, attempts at redefining the family are addressed and a new definition of the family proposed.
- Full Text:
- Date Issued: 1998
- Authors: Ziehl, Susan C
- Date: 1998
- Subjects: Families -- History -- Research Families -- South Africa -- Grahamstown Families Families -- Research -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3341 , http://hdl.handle.net/10962/d1004467
- Description: Drawing on developments in the field of family history and studies of families in contemporary settings, the study addresses the question of explaining variations in household patterns. Its empirical basis is a survey of White households in Grahamstown. The surveyed population was broken down in terms of class (occupation) and culture (language) and analyses conducted to determine if there are any statistically significant relationships between these variables and the tendency to reside in particular household structures. The question of 'family ideology' was also addressed as an attempt was made to uncover subjects' views on a variety of family-related issues. On the basis of the research results, a model of the relationship between class, culture and household structure was developed. Its application to a comparison of Black and White household structures in South Africa as well as the United States, is discussed. Finally, attempts at redefining the family are addressed and a new definition of the family proposed.
- Full Text:
- Date Issued: 1998
The supervisor’s tale: postgraduate supervisors’ experiences in a changing Higher Education environment
- Authors: Searle, Ruth Lesley
- Date: 2015
- Subjects: Graduate students -- Supervision of -- South Africa , Education, Higher -- South Africa , Educational change -- South Africa , Archer, Margaret Scotford -- Political and social views , Critical realism , Knowledge, Sociology of , Dissertations, Academic , Faculty advisors -- South Africa , Education -- Study and teaching (Graduate) -- South Africa , Universities and colleges -- Graduate work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1331 , http://hdl.handle.net/10962/d1019952
- Description: The environment in which higher education institutions operate is changing, and these changes are impacting on all aspects of higher education, including postgraduate levels. Changes wrought by globalisation, heralded by rapid advances in technology have inaugurated a new era in which there are long term consequences for higher education. The shift towards more quantitative and measurable "outputs" signifies a fundamental change in the educational ethos in institutions. Effectiveness is now judged primarily on numbers of graduates and publications rather than on other aspects. The drive is to produce a highly educated population, especially through increasing postgraduates who can drive national innovation and improve national economies. This affects academics in a range of ways, not least in the ways in which they engage in teaching, what they are willing to do and how they do it. Such changes influence the kinds of research done, the structures and funding which support research, and thus naturally shapes the kinds of postgraduate programmes and teaching that occurs. This study, situated in the field of Higher Education Studies, adopting a critical realist stance and drawing on the social theory of Margaret Archer and the concepts of expert and novice, explores the experiences of postgraduate supervisors from one South African institution across a range of disciplines. Individual experiences at the level of the Empirical and embodied in practice at the level of the Actual allow for the identification of possible mechanisms at the level of the Real which structure the sector. The research design then allows for an exploration across mezzo, macro and micro levels. Individuals outline their own particular situations, identifying a number of elements which enabled or constrained them and how, in exercising their agency, they develop their strategies for supervision drawing on a range of different resources that they identify and that may be available to them. Student characteristics, discipline status and placement, funding, and the emergent policy environment are all identified as influencing their practice. In some instances supervisors recognise the broader influences on the system that involve them in their undertaking, noting the international trends. Through their narratives and the discourses they engage a number of contradictions that have developed in the system with growing neo-liberal trends and vocationalism highlighting tensions between academic freedom and autonomy, and demands for productivity, efficiency and compliance, and between an educational focus and a training bias in particular along with others. Especially notable is how this contributes to the current ideologies surrounding knowledge and knowledge production. Their individual interests and concerns, and emergent academic identities as they take shape over time, also modifies the process and how individual supervisors influence their own environments in agentic moves becomes apparent. Whilst often individuals highlight the lack of support especially in the early phases of supervision, the emergent policy-constrained environment is also seen as curtailing possibilities and especially in limiting the possibilities for the exercise of agency. Whilst the study has some limitations in the range and number of respondents nevertheless the data provided rich evidence of how individual supervisors are affected, and how they respond in varied conditions. What is highlighted through these experiences are ways pressures are increasing for both supervisors and students and changing how they engage. Concerns in particular are raised about the growing functional and instrumental nature of the process with an emphasis on the effects on the kinds of researchers being developed and the knowledge that is therefore being produced. As costs increase for academics through the environments developed and with the varied roles they take on so they become more selective and reluctant to expand the role. This research has provided insights into ideas, beliefs and values relating to the postgraduate sector and to the process of postgraduate supervision and how it occurs. This includes the structures and cultural conditions that enable or constrain practitioners as they develop in the role in this particular institution. It has explored some of the ways that mechanisms at international, national and institutional levels shape the role and practices of supervisors. The effects of mechanisms are in no way a given or simply understood. In this way the research may contribute to more emancipatory knowledge which could be used in planning and deciding on emergent policies and practices which might create a more supportive and creative postgraduate environment.
- Full Text:
- Date Issued: 2015
- Authors: Searle, Ruth Lesley
- Date: 2015
- Subjects: Graduate students -- Supervision of -- South Africa , Education, Higher -- South Africa , Educational change -- South Africa , Archer, Margaret Scotford -- Political and social views , Critical realism , Knowledge, Sociology of , Dissertations, Academic , Faculty advisors -- South Africa , Education -- Study and teaching (Graduate) -- South Africa , Universities and colleges -- Graduate work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1331 , http://hdl.handle.net/10962/d1019952
- Description: The environment in which higher education institutions operate is changing, and these changes are impacting on all aspects of higher education, including postgraduate levels. Changes wrought by globalisation, heralded by rapid advances in technology have inaugurated a new era in which there are long term consequences for higher education. The shift towards more quantitative and measurable "outputs" signifies a fundamental change in the educational ethos in institutions. Effectiveness is now judged primarily on numbers of graduates and publications rather than on other aspects. The drive is to produce a highly educated population, especially through increasing postgraduates who can drive national innovation and improve national economies. This affects academics in a range of ways, not least in the ways in which they engage in teaching, what they are willing to do and how they do it. Such changes influence the kinds of research done, the structures and funding which support research, and thus naturally shapes the kinds of postgraduate programmes and teaching that occurs. This study, situated in the field of Higher Education Studies, adopting a critical realist stance and drawing on the social theory of Margaret Archer and the concepts of expert and novice, explores the experiences of postgraduate supervisors from one South African institution across a range of disciplines. Individual experiences at the level of the Empirical and embodied in practice at the level of the Actual allow for the identification of possible mechanisms at the level of the Real which structure the sector. The research design then allows for an exploration across mezzo, macro and micro levels. Individuals outline their own particular situations, identifying a number of elements which enabled or constrained them and how, in exercising their agency, they develop their strategies for supervision drawing on a range of different resources that they identify and that may be available to them. Student characteristics, discipline status and placement, funding, and the emergent policy environment are all identified as influencing their practice. In some instances supervisors recognise the broader influences on the system that involve them in their undertaking, noting the international trends. Through their narratives and the discourses they engage a number of contradictions that have developed in the system with growing neo-liberal trends and vocationalism highlighting tensions between academic freedom and autonomy, and demands for productivity, efficiency and compliance, and between an educational focus and a training bias in particular along with others. Especially notable is how this contributes to the current ideologies surrounding knowledge and knowledge production. Their individual interests and concerns, and emergent academic identities as they take shape over time, also modifies the process and how individual supervisors influence their own environments in agentic moves becomes apparent. Whilst often individuals highlight the lack of support especially in the early phases of supervision, the emergent policy-constrained environment is also seen as curtailing possibilities and especially in limiting the possibilities for the exercise of agency. Whilst the study has some limitations in the range and number of respondents nevertheless the data provided rich evidence of how individual supervisors are affected, and how they respond in varied conditions. What is highlighted through these experiences are ways pressures are increasing for both supervisors and students and changing how they engage. Concerns in particular are raised about the growing functional and instrumental nature of the process with an emphasis on the effects on the kinds of researchers being developed and the knowledge that is therefore being produced. As costs increase for academics through the environments developed and with the varied roles they take on so they become more selective and reluctant to expand the role. This research has provided insights into ideas, beliefs and values relating to the postgraduate sector and to the process of postgraduate supervision and how it occurs. This includes the structures and cultural conditions that enable or constrain practitioners as they develop in the role in this particular institution. It has explored some of the ways that mechanisms at international, national and institutional levels shape the role and practices of supervisors. The effects of mechanisms are in no way a given or simply understood. In this way the research may contribute to more emancipatory knowledge which could be used in planning and deciding on emergent policies and practices which might create a more supportive and creative postgraduate environment.
- Full Text:
- Date Issued: 2015
A new model of the IO-Controlled Jovian decametric radiation
- Authors: Goertz, Christoph K
- Date: 1972
- Subjects: Jupiter (Planet) Radiation Magnetosphere Ionosphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5521 , http://hdl.handle.net/10962/d1012043
- Description: Jupiter, the largest planet in the solar system, is not only an emitter of thermal radiation like any other planet. Jupiter also emits relatively high-intensity non-thermal radiation in two bands, the decimetre wavelength range and the decametre wavelength range (5 MHz< f < 40 MHz). The decimetric radiation is believed to be due to synchrotron radiation of electrons trapped in a kind of Jovian "Van Allen belt". This thesis deals almost exclusively with the decametric radiation. Although the decametric radiation has been observed for 15 years since its discovery by Burke and Franklin in 1955, there is no generally accepted theoretical model of its generation to be found in the literature as yet. This is not surprising, as there are many complex and confusing aspects of the radiation. And since our knowledge of the Jovian ionosphere, magnetosphere and magnetic field is very limited indeed, every theoretical model must be based on some more or less well justified assumptions. It is, however, possible to draw some conclusions from the observed properties of the decimetric and decametric radiation. The radiation in both bands is polarized. It has been shown that at least part of the polarization is an intrinsic property of the radiation source at Jupiter, This indicates the existence of a Jovian magnetic field. The magnitude and shape of the magnetic field, however, is open to discussion, although a dipole field does seem to be a good approximation at least for large distances from Jupiter. Intro. p. 1-2.
- Full Text:
- Date Issued: 1972
- Authors: Goertz, Christoph K
- Date: 1972
- Subjects: Jupiter (Planet) Radiation Magnetosphere Ionosphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5521 , http://hdl.handle.net/10962/d1012043
- Description: Jupiter, the largest planet in the solar system, is not only an emitter of thermal radiation like any other planet. Jupiter also emits relatively high-intensity non-thermal radiation in two bands, the decimetre wavelength range and the decametre wavelength range (5 MHz< f < 40 MHz). The decimetric radiation is believed to be due to synchrotron radiation of electrons trapped in a kind of Jovian "Van Allen belt". This thesis deals almost exclusively with the decametric radiation. Although the decametric radiation has been observed for 15 years since its discovery by Burke and Franklin in 1955, there is no generally accepted theoretical model of its generation to be found in the literature as yet. This is not surprising, as there are many complex and confusing aspects of the radiation. And since our knowledge of the Jovian ionosphere, magnetosphere and magnetic field is very limited indeed, every theoretical model must be based on some more or less well justified assumptions. It is, however, possible to draw some conclusions from the observed properties of the decimetric and decametric radiation. The radiation in both bands is polarized. It has been shown that at least part of the polarization is an intrinsic property of the radiation source at Jupiter, This indicates the existence of a Jovian magnetic field. The magnitude and shape of the magnetic field, however, is open to discussion, although a dipole field does seem to be a good approximation at least for large distances from Jupiter. Intro. p. 1-2.
- Full Text:
- Date Issued: 1972