An assessment of the role of leadership in the successful implementation of performance management : a case of the Eastern Cape district municipalities
- Authors: Dweba, Zandisile Moses
- Date: 2016
- Subjects: Municipal government -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12183 , vital:39194
- Description: At the core of this study is the quest to understand the role leaders play in the successful implementation of performance management in the Eastern Cape municipalities, in the Republic of South Africa. Among the triggers for the study, was the Auditor-General’s lamentation that leaders did not set the correct tone by implementing sound performance management processes, evaluating and monitoring performance in the South African municipalities. He attributed this failure, inter alia, to the lack of employees’ and leadership commitment to the sound implementation of performance management. In an attempt to gain a deeper understanding and possibly respond to the Auditor-Generals’ concern, the researcher sought: To assess the role of leadership and ascertain the extent to which the identified leadership roles were demonstrated in the successful implementation of performance management in the Eastern Cape District Municipalities. Following a review of literature and the conducting of a mixed-methods, empirical study, numerous revelations and findings were made, among which were that, the literature on the leadership-performance link continued to be fragmented and lacking in uniformly defining the concepts, let alone the link between leadership and performance. Because of the multi-dimensionality and the multi-faceted nature of the leadership concept, there still existed a need for more detailed studies on the nature of the leadership-performance link. The eight roles of innovator, broker, producer, director, coordinator, monitor, facilitator and mentor suggested by Quinn, do not provide an exhaustive list of roles, although they provide a starting point on which leader capacitation could be anchored. Whilst the respondents had overwhelmingly affirmed that leaders played the requisite roles in their municipalities, concerns were expressed on deficient leadership competence, poor screening of new leadership entrants, and party political allegiance which was perceived to, at times, cloud their roles. Following a review of literature and past research, numerous studies were uncovered, on the leadership-performance link, which appeared to need consolidation, synthesis and refinement, with a view to sifting and isolating areas that might be of benefit to the implementation of performance management in the Eastern Cape municipalities.
- Full Text:
- Date Issued: 2016
- Authors: Dweba, Zandisile Moses
- Date: 2016
- Subjects: Municipal government -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12183 , vital:39194
- Description: At the core of this study is the quest to understand the role leaders play in the successful implementation of performance management in the Eastern Cape municipalities, in the Republic of South Africa. Among the triggers for the study, was the Auditor-General’s lamentation that leaders did not set the correct tone by implementing sound performance management processes, evaluating and monitoring performance in the South African municipalities. He attributed this failure, inter alia, to the lack of employees’ and leadership commitment to the sound implementation of performance management. In an attempt to gain a deeper understanding and possibly respond to the Auditor-Generals’ concern, the researcher sought: To assess the role of leadership and ascertain the extent to which the identified leadership roles were demonstrated in the successful implementation of performance management in the Eastern Cape District Municipalities. Following a review of literature and the conducting of a mixed-methods, empirical study, numerous revelations and findings were made, among which were that, the literature on the leadership-performance link continued to be fragmented and lacking in uniformly defining the concepts, let alone the link between leadership and performance. Because of the multi-dimensionality and the multi-faceted nature of the leadership concept, there still existed a need for more detailed studies on the nature of the leadership-performance link. The eight roles of innovator, broker, producer, director, coordinator, monitor, facilitator and mentor suggested by Quinn, do not provide an exhaustive list of roles, although they provide a starting point on which leader capacitation could be anchored. Whilst the respondents had overwhelmingly affirmed that leaders played the requisite roles in their municipalities, concerns were expressed on deficient leadership competence, poor screening of new leadership entrants, and party political allegiance which was perceived to, at times, cloud their roles. Following a review of literature and past research, numerous studies were uncovered, on the leadership-performance link, which appeared to need consolidation, synthesis and refinement, with a view to sifting and isolating areas that might be of benefit to the implementation of performance management in the Eastern Cape municipalities.
- Full Text:
- Date Issued: 2016
An ethnographic study of beginner mathematics teachers’ classroom practices in the first three years of their employment: Shaping of a Professional Identity
- Narayanan, Ajayagosh Ettappiriparambil
- Authors: Narayanan, Ajayagosh Ettappiriparambil
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2069 , http://hdl.handle.net/10962/d1020967
- Description: The main theme in this study examines how beginner mathematics teachers (BTs) shape their professional identity in their first three years of classroom practices in Lesotho. This study, which focuses particularly on BTs’ second and third year of employment, gathers data with an understanding that the notion of professional identity is multi-faceted. Professional identity embraces a host of other identities such as personal identity, teacher identity, mathematics identity and community of practice identity. This study is framed by social theories of learning. Learning occurs by active participation and practice. BTs’ peripheral participation assists them in making sense of the activities (situated learning) in which they are engaged, in the classrooms. The sense making processes eventually shape their professional identity. In line with situated meanings that BTs form, the key notion (professional identity) is further categorised into personal identity, teacher identity, mathematics identity and community of practice identity. These identities integrate to become the professional identity of a beginner mathematics teacher. Using a narrative ethnographic approach as the research method, I have made use of extensive classroom observations and interviews to gather data. In this study, six volunteer participant BTs were originally selected. These teachers were from two districts, Berea and Maseru in Lesotho. After being observed in the classrooms, these teachers were interviewed. In the third year of the study, one participant withdrew from the study. I used vertical (descriptive) analysis to narrate their classroom practice followed by horizontal analysis to understand how they shape their professional identity. The analytical model enables the researcher to analyse the data in order to establish how the BTs’ actions, their reflexive stories and their journey in becoming a mathematics teacher shape their professional identity. The recurring themes that emerged from the horizontal analysis are the ways BTs approach the classroom practice which is dominated by teacher-centred learning. This involves demonstrating an example and then students following this model to practice more examples. In this sense, their approach is the same though these BTs started understanding how their classroom approaches can bring changes in the learning of mathematics. I analysed the utterances from the BTs’ classroom activities by separating these into mathematizing and subjectifying. The subjectifying utterances were further analysed to understand how these created meaning. These, in my view, are also central features of a teacher’s practice that need interpretation in order to understand the shaping of a professional identity. The key finding is that their narrative helped them to understand how they shape their professional identity. The study highlights the importance of listening to BTs’ stories of how they become mathematics teachers. Their narratives can be the benchmark for stake-holders, policy makers and potential researchers as the study on BTs’ professional identity is relatively new in Lesotho.
- Full Text:
- Date Issued: 2016
- Authors: Narayanan, Ajayagosh Ettappiriparambil
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2069 , http://hdl.handle.net/10962/d1020967
- Description: The main theme in this study examines how beginner mathematics teachers (BTs) shape their professional identity in their first three years of classroom practices in Lesotho. This study, which focuses particularly on BTs’ second and third year of employment, gathers data with an understanding that the notion of professional identity is multi-faceted. Professional identity embraces a host of other identities such as personal identity, teacher identity, mathematics identity and community of practice identity. This study is framed by social theories of learning. Learning occurs by active participation and practice. BTs’ peripheral participation assists them in making sense of the activities (situated learning) in which they are engaged, in the classrooms. The sense making processes eventually shape their professional identity. In line with situated meanings that BTs form, the key notion (professional identity) is further categorised into personal identity, teacher identity, mathematics identity and community of practice identity. These identities integrate to become the professional identity of a beginner mathematics teacher. Using a narrative ethnographic approach as the research method, I have made use of extensive classroom observations and interviews to gather data. In this study, six volunteer participant BTs were originally selected. These teachers were from two districts, Berea and Maseru in Lesotho. After being observed in the classrooms, these teachers were interviewed. In the third year of the study, one participant withdrew from the study. I used vertical (descriptive) analysis to narrate their classroom practice followed by horizontal analysis to understand how they shape their professional identity. The analytical model enables the researcher to analyse the data in order to establish how the BTs’ actions, their reflexive stories and their journey in becoming a mathematics teacher shape their professional identity. The recurring themes that emerged from the horizontal analysis are the ways BTs approach the classroom practice which is dominated by teacher-centred learning. This involves demonstrating an example and then students following this model to practice more examples. In this sense, their approach is the same though these BTs started understanding how their classroom approaches can bring changes in the learning of mathematics. I analysed the utterances from the BTs’ classroom activities by separating these into mathematizing and subjectifying. The subjectifying utterances were further analysed to understand how these created meaning. These, in my view, are also central features of a teacher’s practice that need interpretation in order to understand the shaping of a professional identity. The key finding is that their narrative helped them to understand how they shape their professional identity. The study highlights the importance of listening to BTs’ stories of how they become mathematics teachers. Their narratives can be the benchmark for stake-holders, policy makers and potential researchers as the study on BTs’ professional identity is relatively new in Lesotho.
- Full Text:
- Date Issued: 2016
An evaluation of sampling and statistical methods for long-term monitoring of subtidal reef fishes : a case study of Tsitsikamma National Park marine protected area
- Authors: Parker, Denham
- Date: 2016
- Subjects: Reef fishes -- South Africa -- Monitoring , Tsitsikamma National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5385 , http://hdl.handle.net/10962/d1019991
- Description: Tsitsikamma National Park (TNP) possesses the oldest (established 1954), and one of the largest (350 km2) ‘no-take’ marine protected areas (MPA) in South Africa. A long-term monitoring (LTM) programme to observe the subtidal reef fishes in the TNP MPA was established in 2007. To date, 243 angling replicates have been completed, and a total of 2,751 fish belonging to 41 different species have been caught and released. In an era of unprecedented global biodiversity loss, data that can be used to monitor ecosystems and gauge changes in biodiversity through time are essential. This thesis aims to improve the methodological and statistical processes currently available for LTM of subtidal reef fish by providing an evaluation of the TNP MPA LTM programme. Angling data revealed definitive spatial structuring, in the form of spatial autocorrelation, and a shift in viewing spatial dependency as a statistical obstacle to a source of ecological information created a new avenue of data inference. Species-specific distribution maps identified localized habitat as the main predictor variable for species abundance, emphasizing the need for accurate a priori bathymetric information for subtidal monitoring. ‘Random forest’ analyses confirmed spatial variables are more important than temporal variables in predicting species abundance. The effectiveness of Generalized Linear Mixed Models (GAMMs) to account for spatial autocorrelation was highlighted, and evidence that disregarding spatial dependencies in temporal analyses can produce erroneous results was illustrated in the case of dageraad (Chrysoblephus cristiceps). Correlograms indicated that the current sampling strategy produced spatially redundant data and the sampling unit size (150 m2) could be doubled to optimize sampling. Temporal analyses demonstrated that after 50 years of ‘no take’ protection the TNP MPA ichthyofauna exhibits a high level of stability. Species-specific size structure was also found to be highly stable. Dageraad was the only species to exhibit a definitive temporal trend in their size structure, which was attributed to recruitment variation and the possibility that large individuals may migrate out of the study area. The inadequacy of angling as a method for monitoring a broad spectrum of the fish species was highlighted, particularly due to its selectivity towards large predators. As a result, a new sampling technique known as Stereo Baited Remote Underwater Videos (stereo-BRUVs) was introduced to the LTM programme in 2013. Stereo-BRUVs enabled sampling of 2640 fish belonging to 52 different species, from 57 samples collected in less than two years. A comparison of the sampling methods concluded that, compared to angling, stereo-BRUVs provide a superior technique that can survey a significantly larger proportion of the ichthyofauna with minimal length-selectivity biases. In addition, stereo-BRUVs possess a higher statistical power to detect changes in population abundance. However, a potential bias in the form of ‘hyperstability’ in sites with unusually high fish densities was identified as a possible flaw when using stereo-BRUVs. In an attempt to provide a more rigorous method evaluation, simulation testing was employed to assess the ability of angling and stereo-BRUVs to accurately describe a decreasing population. The advantage of this approach is that the simulated population abundances are known, so that each sampling method can be tested in terms of how well it tracks known abundance trends. The study established that stereo- BRUVs provided more accurate data when describing a distinct population decline of roman (Chrysoblephus laticeps) over 10- and 20-year periods. In addition, spawner-biomass was found to be a more accurate population estimate than relative abundance estimates (CPUE and MaxN) due to the inclusion of population size structure information, highlighting the importance of length-frequency data. The study illustrated that an evaluation framework that utilizes simulation testing has the potential to optimize LTM sampling procedures by addressing a number of methodological questions. This includes developing a procedure that aligns data collected from different sampling methods by applying correction factors, thus ensuring LTM programmes are able to adapt sampling strategies without losing data continuity.
- Full Text:
- Date Issued: 2016
- Authors: Parker, Denham
- Date: 2016
- Subjects: Reef fishes -- South Africa -- Monitoring , Tsitsikamma National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5385 , http://hdl.handle.net/10962/d1019991
- Description: Tsitsikamma National Park (TNP) possesses the oldest (established 1954), and one of the largest (350 km2) ‘no-take’ marine protected areas (MPA) in South Africa. A long-term monitoring (LTM) programme to observe the subtidal reef fishes in the TNP MPA was established in 2007. To date, 243 angling replicates have been completed, and a total of 2,751 fish belonging to 41 different species have been caught and released. In an era of unprecedented global biodiversity loss, data that can be used to monitor ecosystems and gauge changes in biodiversity through time are essential. This thesis aims to improve the methodological and statistical processes currently available for LTM of subtidal reef fish by providing an evaluation of the TNP MPA LTM programme. Angling data revealed definitive spatial structuring, in the form of spatial autocorrelation, and a shift in viewing spatial dependency as a statistical obstacle to a source of ecological information created a new avenue of data inference. Species-specific distribution maps identified localized habitat as the main predictor variable for species abundance, emphasizing the need for accurate a priori bathymetric information for subtidal monitoring. ‘Random forest’ analyses confirmed spatial variables are more important than temporal variables in predicting species abundance. The effectiveness of Generalized Linear Mixed Models (GAMMs) to account for spatial autocorrelation was highlighted, and evidence that disregarding spatial dependencies in temporal analyses can produce erroneous results was illustrated in the case of dageraad (Chrysoblephus cristiceps). Correlograms indicated that the current sampling strategy produced spatially redundant data and the sampling unit size (150 m2) could be doubled to optimize sampling. Temporal analyses demonstrated that after 50 years of ‘no take’ protection the TNP MPA ichthyofauna exhibits a high level of stability. Species-specific size structure was also found to be highly stable. Dageraad was the only species to exhibit a definitive temporal trend in their size structure, which was attributed to recruitment variation and the possibility that large individuals may migrate out of the study area. The inadequacy of angling as a method for monitoring a broad spectrum of the fish species was highlighted, particularly due to its selectivity towards large predators. As a result, a new sampling technique known as Stereo Baited Remote Underwater Videos (stereo-BRUVs) was introduced to the LTM programme in 2013. Stereo-BRUVs enabled sampling of 2640 fish belonging to 52 different species, from 57 samples collected in less than two years. A comparison of the sampling methods concluded that, compared to angling, stereo-BRUVs provide a superior technique that can survey a significantly larger proportion of the ichthyofauna with minimal length-selectivity biases. In addition, stereo-BRUVs possess a higher statistical power to detect changes in population abundance. However, a potential bias in the form of ‘hyperstability’ in sites with unusually high fish densities was identified as a possible flaw when using stereo-BRUVs. In an attempt to provide a more rigorous method evaluation, simulation testing was employed to assess the ability of angling and stereo-BRUVs to accurately describe a decreasing population. The advantage of this approach is that the simulated population abundances are known, so that each sampling method can be tested in terms of how well it tracks known abundance trends. The study established that stereo- BRUVs provided more accurate data when describing a distinct population decline of roman (Chrysoblephus laticeps) over 10- and 20-year periods. In addition, spawner-biomass was found to be a more accurate population estimate than relative abundance estimates (CPUE and MaxN) due to the inclusion of population size structure information, highlighting the importance of length-frequency data. The study illustrated that an evaluation framework that utilizes simulation testing has the potential to optimize LTM sampling procedures by addressing a number of methodological questions. This includes developing a procedure that aligns data collected from different sampling methods by applying correction factors, thus ensuring LTM programmes are able to adapt sampling strategies without losing data continuity.
- Full Text:
- Date Issued: 2016
An exploration of challenges in leadership development within Eskom's distribution division operating unit : a case-study of Limpopo Province
- Authors: Mashau, Mbangiseni Adam
- Date: 2016
- Subjects: Eskom (Firm) Leadership -- South Africa Government business enterprises -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8198 , vital:31965
- Description: Although the issue of leadership is a sensitive subject especially when dealt with it in the context of State Owned Entities operations, avoiding the need to highlight the seriousness of plights and challenges hampering adequate development of current and prospective leaders may be regarded as an act of ignorance. It is certainly better to have the knowledge and not use it than to want to use critical information but you do not have it at all. As South Africans, we are currently more than lucky to be living in the democratic era where a thirst and hunger of knowledge is entirely one’s choice. The South African communities and Sate Owned Enterprises leaders deserve to be informed about issues regarding the performance of these entities in order for them to partake positively. State Owned Entities are undoubtedly the face of the country and consequently, their leadership is expected to play exemplary role of the highest order because their acts and/or omissions may not go unnoticed. Although all State Owned Entities are essential, Eskom is known to be the blood and oxygen for the country’s competitiveness and driving force behind the economy. Adequate leadership development within Eskom’s Limpopo Operating Unit can only positively impact on the major operations in the province and the country in particular. Although Eskom Distribution Division is found throughout South Africa, Limpopo province was selected to be a case to be studied. The study used a qualitative research methodology with the aim of eliciting narrated data from participants. Through this research methodology, a focus group approach was applied in order to narrow down the scope of the study. The study revealed that factors such as lack of self-confidence, fear of possible positional take-over by new comers, lack of succession planning and failure to implement the contents of Individual Development Plans are amongst a barrage of hindrances of adequate leadership development in the Business Unit. Despite the fact that the aforementioned impediments are seemingly known by the Business Unit’s senior management, it has also been revealed that officials are obscured by the need to focus on results whilst neglecting development of human capital. Due to the critical role that is played by Eskom in the country, the study has potential of positively contributing to the body of knowledge, other SOEs and professional practices in general.
- Full Text:
- Date Issued: 2016
- Authors: Mashau, Mbangiseni Adam
- Date: 2016
- Subjects: Eskom (Firm) Leadership -- South Africa Government business enterprises -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8198 , vital:31965
- Description: Although the issue of leadership is a sensitive subject especially when dealt with it in the context of State Owned Entities operations, avoiding the need to highlight the seriousness of plights and challenges hampering adequate development of current and prospective leaders may be regarded as an act of ignorance. It is certainly better to have the knowledge and not use it than to want to use critical information but you do not have it at all. As South Africans, we are currently more than lucky to be living in the democratic era where a thirst and hunger of knowledge is entirely one’s choice. The South African communities and Sate Owned Enterprises leaders deserve to be informed about issues regarding the performance of these entities in order for them to partake positively. State Owned Entities are undoubtedly the face of the country and consequently, their leadership is expected to play exemplary role of the highest order because their acts and/or omissions may not go unnoticed. Although all State Owned Entities are essential, Eskom is known to be the blood and oxygen for the country’s competitiveness and driving force behind the economy. Adequate leadership development within Eskom’s Limpopo Operating Unit can only positively impact on the major operations in the province and the country in particular. Although Eskom Distribution Division is found throughout South Africa, Limpopo province was selected to be a case to be studied. The study used a qualitative research methodology with the aim of eliciting narrated data from participants. Through this research methodology, a focus group approach was applied in order to narrow down the scope of the study. The study revealed that factors such as lack of self-confidence, fear of possible positional take-over by new comers, lack of succession planning and failure to implement the contents of Individual Development Plans are amongst a barrage of hindrances of adequate leadership development in the Business Unit. Despite the fact that the aforementioned impediments are seemingly known by the Business Unit’s senior management, it has also been revealed that officials are obscured by the need to focus on results whilst neglecting development of human capital. Due to the critical role that is played by Eskom in the country, the study has potential of positively contributing to the body of knowledge, other SOEs and professional practices in general.
- Full Text:
- Date Issued: 2016
An exploration of financial conscientiousness among School Governing Bodies and School Management Teams and its impact on Boundary Spanning Management on selected Section 21 High Schools in the Eastern Cape Province
- Authors: Sifuba, Mpilo
- Date: 2016
- Subjects: Financial conscientiousness Finacial statements -- Standards -- School governing bodies and school management teams Charter Schools -- Finance -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: http://hdl.handle.net/11260/878 , vital:29940
- Description: The study investigated the underlying factors which induce the School Governing Bodies (SGBs) and School Management Teams (SMTs) to boundary cross into each other’s finance functional domain despite the fact that their responsibilities are demarcated in the South African Schools Act No. 84 of 1996. The study also intended to examine financial conscientiousness as a critical strategy, which was aimed at achieving the following: restricting the boundary spanning management among School Governing Bodies and School Management Teams, giving direction and strengthening the relationship between the two structures in section 21 high schools. Pragmatism was used as a paradigm for this study as it has been hailed as one of the best paradigms for justifying the use of mixed methods research. The researcher located the study within mixed methods research and employed the convergent parallel design characterised by collecting concurrently both qualitative and quantitative data. The study used a nonprobability sampling strategy – a purposive sampling technique. The study focused on 147 participants. The sample consisted of the following participant sub-groups: (a) 138 questionnaires participants (46 school principals, 46 SGB chairpersons and 46 school finance officers) sampled from 46 high schools, and (b) 9 face-to-face interviews participants (3 school principals, 3 SGB chairpersons) and purposively sampled from 3 different section 21 high schools located in rural, semi-urban and urban areas of the Butterworth District, and 3 Departmental Officials (The District Director, An Education Development Officer, and District National Norms and Standards for School funding coordinator) sampled from the Butterworth Education District. The study was guided by the following research question: What ideas of consciousness raising strategies could help alleviate the crossing over of boundaries between SGBs and SMTs on financial matters of the section 21 high schools? The financial conscientiousness conceptual framework for this study hinged on the conscious raising concept of Paulo Freire supported by philosophical ideas of theorists of school-based management concept, school-based participative partnership concept, school-based participative management concept and teamwork concept. These theories are expected to encourage the inclusive participation when finances are handled in section 21 high schools. The study used a survey questionnaire to collect quantitative dataset and interviews for the qualitative dataset to find answers to the research question and also to enhance the reliability and validity of the research findings. The quantitative data were presented in tables with frequencies and percentages as well as pie charts. Themes and Natural Meaning Units (NMUs) were used to analyse the qualitative data. The overall findings backed by the extant literature and research data indicated that there was lack of trust among SGBs and SMTs. Owing to this mistrust the day to day activities of the school were compromised. There were power struggles between SGBs and SMTs in schools for the control of school finances. There were corrupt practices by both SGBs and SMTs in the management of school finances. The findings also revealed lack of capacity building by the department of education. Furthermore, the SGBs parent component was characterised by high illiteracy level – a systemic weakness worsened by the manipulation perpetrated by both school governing bodies and school management teams during school finance management processes. Resulting from the data analysis, the study recommended the utilisation and application of Sifuba’s School Finance Management Awareness Model (SSFMA) as a new model that could be adopted and adapted by the Department of Education for the school finance management. This will create educational sound atmosphere and realities at school level – a model that is capable of inducing the participative and inclusive behaviour of the SGBs and SMTs when they perform their financial responsibilities
- Full Text:
- Date Issued: 2016
- Authors: Sifuba, Mpilo
- Date: 2016
- Subjects: Financial conscientiousness Finacial statements -- Standards -- School governing bodies and school management teams Charter Schools -- Finance -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: http://hdl.handle.net/11260/878 , vital:29940
- Description: The study investigated the underlying factors which induce the School Governing Bodies (SGBs) and School Management Teams (SMTs) to boundary cross into each other’s finance functional domain despite the fact that their responsibilities are demarcated in the South African Schools Act No. 84 of 1996. The study also intended to examine financial conscientiousness as a critical strategy, which was aimed at achieving the following: restricting the boundary spanning management among School Governing Bodies and School Management Teams, giving direction and strengthening the relationship between the two structures in section 21 high schools. Pragmatism was used as a paradigm for this study as it has been hailed as one of the best paradigms for justifying the use of mixed methods research. The researcher located the study within mixed methods research and employed the convergent parallel design characterised by collecting concurrently both qualitative and quantitative data. The study used a nonprobability sampling strategy – a purposive sampling technique. The study focused on 147 participants. The sample consisted of the following participant sub-groups: (a) 138 questionnaires participants (46 school principals, 46 SGB chairpersons and 46 school finance officers) sampled from 46 high schools, and (b) 9 face-to-face interviews participants (3 school principals, 3 SGB chairpersons) and purposively sampled from 3 different section 21 high schools located in rural, semi-urban and urban areas of the Butterworth District, and 3 Departmental Officials (The District Director, An Education Development Officer, and District National Norms and Standards for School funding coordinator) sampled from the Butterworth Education District. The study was guided by the following research question: What ideas of consciousness raising strategies could help alleviate the crossing over of boundaries between SGBs and SMTs on financial matters of the section 21 high schools? The financial conscientiousness conceptual framework for this study hinged on the conscious raising concept of Paulo Freire supported by philosophical ideas of theorists of school-based management concept, school-based participative partnership concept, school-based participative management concept and teamwork concept. These theories are expected to encourage the inclusive participation when finances are handled in section 21 high schools. The study used a survey questionnaire to collect quantitative dataset and interviews for the qualitative dataset to find answers to the research question and also to enhance the reliability and validity of the research findings. The quantitative data were presented in tables with frequencies and percentages as well as pie charts. Themes and Natural Meaning Units (NMUs) were used to analyse the qualitative data. The overall findings backed by the extant literature and research data indicated that there was lack of trust among SGBs and SMTs. Owing to this mistrust the day to day activities of the school were compromised. There were power struggles between SGBs and SMTs in schools for the control of school finances. There were corrupt practices by both SGBs and SMTs in the management of school finances. The findings also revealed lack of capacity building by the department of education. Furthermore, the SGBs parent component was characterised by high illiteracy level – a systemic weakness worsened by the manipulation perpetrated by both school governing bodies and school management teams during school finance management processes. Resulting from the data analysis, the study recommended the utilisation and application of Sifuba’s School Finance Management Awareness Model (SSFMA) as a new model that could be adopted and adapted by the Department of Education for the school finance management. This will create educational sound atmosphere and realities at school level – a model that is capable of inducing the participative and inclusive behaviour of the SGBs and SMTs when they perform their financial responsibilities
- Full Text:
- Date Issued: 2016
An exploration of how consistently and precisely mathematics teachers code-switch in multilingual classrooms
- Authors: Chikiwa, Clemence
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2076 , http://hdl.handle.net/10962/d1021304
- Description: Many education research studies conducted in and outside South Africa encourage teachers to take advantage of the presence of multilingualism in their classrooms and to use it to the advancement of students’ conceptual learning. This study adopts the notion that code switching is a potential resource that teachers can use when teaching multilingual mathematics classes. The aim of this study is to determine how precisely and consistently selected teachers of multilingual mathematics classes code switched during teaching of trigonometry and geometry at secondary school. This study is informed by socio-cultural theory in general and Vygotsky’s work in particular. It focussed specifically on the critical role that language plays in the teaching and cognitive development of mathematics. My study situated within an interpretivist paradigm, used a case study research design and a mixed method research approach. Data were obtained through document collection, observing and interviewing three Grade 11 Mathematics teachers purposively selected from three secondary schools in Grahamstown and King Williamstown education districts of the Eastern Cape Province, South Africa. Data were quantitatively and qualitatively analysed. Findings from this study revealed that the frequency of code switching was not consistent across teachers, topics and lessons. Teachers taught predominantly in the public domain exposing students to compromised mathematical content through their code switching practices. Borrowing code switching was prevalently employed consistently across the participating teachers. Very little transparent code switching, from mainly those mathematical terms commonly used in the foundation and the intermediate phases, was evident in teacher language. No Grade 11 trigonometry and geometry terms in isiXhosa were transparently and consistently code switched. The data suggested that while precision was observed in some cases, it was not consistent. Inconsistencies were caused by lack of planning for code switching, lack of teaching materials in indigenous languages, selective code switching, and ‘safe mode’ code switching strategies which affected teachers’ pedagogical practices. Overall results in this study illustrate that the lack of planning for code switching and the lack of explicit policies and clear-cut official positions on code switching for teaching has contributed to inconsistent and imprecise code switching by the participating teachers. This study concludes that the development of supporting mechanisms, identifying and documenting best practices to encourage transparent, meaningful and beneficial code switching is urgently required to aid and promote conceptual understanding of strongly bounded sub-registers of secondary school mathematics such as trigonometry and geometry. It is anticipated that this study will contribute significantly to the ongoing debate on language use in education and to the institution of best practices for judicious, consistent and precise use of students’ home language during the teaching of mathematics in South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Chikiwa, Clemence
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2076 , http://hdl.handle.net/10962/d1021304
- Description: Many education research studies conducted in and outside South Africa encourage teachers to take advantage of the presence of multilingualism in their classrooms and to use it to the advancement of students’ conceptual learning. This study adopts the notion that code switching is a potential resource that teachers can use when teaching multilingual mathematics classes. The aim of this study is to determine how precisely and consistently selected teachers of multilingual mathematics classes code switched during teaching of trigonometry and geometry at secondary school. This study is informed by socio-cultural theory in general and Vygotsky’s work in particular. It focussed specifically on the critical role that language plays in the teaching and cognitive development of mathematics. My study situated within an interpretivist paradigm, used a case study research design and a mixed method research approach. Data were obtained through document collection, observing and interviewing three Grade 11 Mathematics teachers purposively selected from three secondary schools in Grahamstown and King Williamstown education districts of the Eastern Cape Province, South Africa. Data were quantitatively and qualitatively analysed. Findings from this study revealed that the frequency of code switching was not consistent across teachers, topics and lessons. Teachers taught predominantly in the public domain exposing students to compromised mathematical content through their code switching practices. Borrowing code switching was prevalently employed consistently across the participating teachers. Very little transparent code switching, from mainly those mathematical terms commonly used in the foundation and the intermediate phases, was evident in teacher language. No Grade 11 trigonometry and geometry terms in isiXhosa were transparently and consistently code switched. The data suggested that while precision was observed in some cases, it was not consistent. Inconsistencies were caused by lack of planning for code switching, lack of teaching materials in indigenous languages, selective code switching, and ‘safe mode’ code switching strategies which affected teachers’ pedagogical practices. Overall results in this study illustrate that the lack of planning for code switching and the lack of explicit policies and clear-cut official positions on code switching for teaching has contributed to inconsistent and imprecise code switching by the participating teachers. This study concludes that the development of supporting mechanisms, identifying and documenting best practices to encourage transparent, meaningful and beneficial code switching is urgently required to aid and promote conceptual understanding of strongly bounded sub-registers of secondary school mathematics such as trigonometry and geometry. It is anticipated that this study will contribute significantly to the ongoing debate on language use in education and to the institution of best practices for judicious, consistent and precise use of students’ home language during the teaching of mathematics in South Africa.
- Full Text:
- Date Issued: 2016
An investigation into the public policy making role of the judiciary :The case of South Africa
- Authors: Maluleke, Life Reuben
- Date: 2016
- Subjects: Policy sciences -- South Africa Political planning -- South Africa Public opinion -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9812 , vital:35005
- Full Text: false
- Date Issued: 2016
- Authors: Maluleke, Life Reuben
- Date: 2016
- Subjects: Policy sciences -- South Africa Political planning -- South Africa Public opinion -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9812 , vital:35005
- Full Text: false
- Date Issued: 2016
An investigation into the survival strategies of the rural elderly in Zimbabwe: a case study of Hobodo ward in Mangwe District in Zimbabwe
- Authors: Marazi, Tafara
- Date: 2016
- Subjects: Rural elderly -- Zimbabwe , Elderly poor -- Zimbabwe , Ophans -- Services for -- Zimbabwe , AIDS (Disease) -- Zimbabwe , Child welfare -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3407 , http://hdl.handle.net/10962/d1020605
- Description: The thesis focuses on the survival mechanisms of the rural poor elderly in Zimbabwe. The situation of the rural elderly is looked at in the context of the ravaging HIV/AIDS pandemic. The focus is specifically directed on the increasing numbers of orphans who are generated following the rampant deaths of their parents (sexually active individuals). With Africa failing to effectively withstand the forcefulness of the pandemic, the community structures in Zimbabwe are being heavily shaken to the detriment of all social groups. It is within this continuum that the research is laid out to investigate the situation on the ground. In this case, a fieldwork exercise was carried out in the Hobodo ward of Mangwe district in Zimbabwe. An intensive and in-depth examination of the critical situation was pursued under the case study model. To make the study more focused, the elderly were placed under investigation with regards to their new role of providing familial care for the orphans. The manner in which they face such a towering task under strained resources and limited knowhow was explored. The well-being of the orphans was also investigated in close relation to the welfare efforts of the elderly guardians. The investigations were made in respect of the contribution of the local resources towards the innovativeness of the elderly guardians. The adaptivity of the elderly and the versatility of the orphans were examined within the confines of the social and the economic capitals of the Hobodo ward. It is within the natural, social and economic capital dimensions of the Hobodo rural locality that the applicability of the sustainable livelihoods framework in explaining the dire social situation of the elderly and the orphans was brought under spotlight. The study was pursued through the qualitative research paradigm. This was done to capture the social perceptions, beliefs and the innovative capabilities of the elderly in their natural environment; and under the fieldwork setting. Several data collection techniques were employed to unveil the subject under study. These included interviews, questionnaires, participant observations, focus group discussions. Sampling was used to produce the research framework. Participants in the research were largely identified through random sampling. In special circumstances, purposive sampling was used. Tape recording and note taking were largely used to capture the responses of the research participants.
- Full Text:
- Date Issued: 2016
- Authors: Marazi, Tafara
- Date: 2016
- Subjects: Rural elderly -- Zimbabwe , Elderly poor -- Zimbabwe , Ophans -- Services for -- Zimbabwe , AIDS (Disease) -- Zimbabwe , Child welfare -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3407 , http://hdl.handle.net/10962/d1020605
- Description: The thesis focuses on the survival mechanisms of the rural poor elderly in Zimbabwe. The situation of the rural elderly is looked at in the context of the ravaging HIV/AIDS pandemic. The focus is specifically directed on the increasing numbers of orphans who are generated following the rampant deaths of their parents (sexually active individuals). With Africa failing to effectively withstand the forcefulness of the pandemic, the community structures in Zimbabwe are being heavily shaken to the detriment of all social groups. It is within this continuum that the research is laid out to investigate the situation on the ground. In this case, a fieldwork exercise was carried out in the Hobodo ward of Mangwe district in Zimbabwe. An intensive and in-depth examination of the critical situation was pursued under the case study model. To make the study more focused, the elderly were placed under investigation with regards to their new role of providing familial care for the orphans. The manner in which they face such a towering task under strained resources and limited knowhow was explored. The well-being of the orphans was also investigated in close relation to the welfare efforts of the elderly guardians. The investigations were made in respect of the contribution of the local resources towards the innovativeness of the elderly guardians. The adaptivity of the elderly and the versatility of the orphans were examined within the confines of the social and the economic capitals of the Hobodo ward. It is within the natural, social and economic capital dimensions of the Hobodo rural locality that the applicability of the sustainable livelihoods framework in explaining the dire social situation of the elderly and the orphans was brought under spotlight. The study was pursued through the qualitative research paradigm. This was done to capture the social perceptions, beliefs and the innovative capabilities of the elderly in their natural environment; and under the fieldwork setting. Several data collection techniques were employed to unveil the subject under study. These included interviews, questionnaires, participant observations, focus group discussions. Sampling was used to produce the research framework. Participants in the research were largely identified through random sampling. In special circumstances, purposive sampling was used. Tape recording and note taking were largely used to capture the responses of the research participants.
- Full Text:
- Date Issued: 2016
An investigation of the morphological and electrochemical properties of spinel cathode oxide materials used in li-ion batteries
- Authors: Snyders, Charmelle
- Date: 2016
- Subjects: Lithium ion batteries Cathodes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12929 , vital:27135
- Description: Li-ion batteries have become the more dominant battery type used in portable electronic devices such as cell phones, computers and more recently their application in full electric vehicles (EV). Li-ion batteries have many advantages over the traditional rechargeable systems (Pb-acid and Ni-MH) such as their higher energy density, low self-discharge, long capacity cycle life and relatively maintenance free. Due to their commercial advantages, a lot of research is done in developing new novel Li-ion electrode materials, improving existing ones and to reduce manufacturing costs in order to make them more cost effective in their applications. This study looked at the cathode material chemistry that has a typical spinel manganese oxide (LiMn2O4) type structure. For comparison the study also considered the influence of doping the phase with various metals such as Al, Mg, Co and Ni that were made as precursors using various carboxylic acids (Citric, Ascorbic, Succinic and Poly-acrylic acid) from a sol-gel process. Traditional batch methods of synthesizing the electrode material is costly and do not necessarily provide optimized electrochemical performance. Alternative continuous less energy intensive methods would help reduce the costs of the preparation of the electrode materials. This study investigated the influence of two synthesis techniques on the materials physical and electrochemical characteristics. These synthesis methods included the use of a typical batch sol-gel method and the continuous spray-drying technique. The spinel materials were prepared and characterized by Powder X-Ray Diffraction (PXRD) to confirm the formation of various phases during the synthesis process. In addition, in-situ PXRD techniques were used to track the phase changes that occurred in the typical batch synthesis process from a sol-gel mixture to the final crystalline spinel oxide. The materials were also characterized by thermal gravimetric analysis (TGA), whereby the materials decomposition mechanisms were observed as the precursor was gradually heated to the final oxide. These synthesized materials prepared under various conditions were then used to build suitable Li-ion coin type of cells, whereby their electrochemical properties were tested by simple capacity tests and electrochemical impedance spectroscopy (EIS). EIS measurements were done on the built cells with the various materials at various charge voltages. TG analysis showed that the materials underwent multiple decomposition steps upon heating for the doped lithium manganese oxides, whereas the undoped oxide showed only a single decomposition step. The results showed that all the materials achieved their weight loss below 400 °C, and that the final spinel oxide had already formed. The in-situ PXRD analysis showed the progression of the phase transitions where certain of the materials changed from a crystalline precursor to an amorphous intermediate phase and then finally to the spinel cathode oxide (Li1.03Mg0.2Mn1.77O4, and LiCo1.09Mn0.91O4). For other materials, the precursor would start as an amorphous phase, and then upon heating, convert into an impure intermediate phase (Mn2O3) before forming the final spinel oxide (Li1.03Mn1.97O4 and LiNi0.5Mn1.5O4). The in-situ study also showed the increases in the materials respective lattice parameters of the crystalline unit cells upon heating and the significant increases in their crystallite sizes when heated above 600 °C. Hence the results implied that a type of sintering of the particles would occur at temperatures above 600 °C, thereby increasing the respective crystallite size. The study showed that the cathode active materials made by the sol-gel spray-drying method would give a material that had a significantly larger surface area and a smaller crystallite size when compared to the materials made by the batch process. The electrochemical analysis showed that there was only a slight increase in the discharge capacities of the cells made with the spray-drying technique when compared to the cells made with the materials from the batch sol-gel technique. Whereas, the EIS study showed that there were distinct differences in the charging behavior of the cells made with the various materials using different synthesis techniques. The EIS results showed that there was a general decrease in the cells charge transfer resistance (Rct) as the charge potential increased regardless of the synthesis method used for the various materials. The results also showed that the lithium-ion diffusion coefficient (DLi) obtained from EIS measurements were in most of the samples higher for the cathode materials that had a larger surface area. This implied that the Li-ion could diffuse at a faster rate through the bulk material. The study concluded that by optimizing the synthesis process in terms of the careful control of the thermal parameters, the Li-ion batteries‟ cathode active material of the manganese spinel type could be optimized and be manufactured by using a continuous flow micro spray process.
- Full Text:
- Date Issued: 2016
- Authors: Snyders, Charmelle
- Date: 2016
- Subjects: Lithium ion batteries Cathodes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12929 , vital:27135
- Description: Li-ion batteries have become the more dominant battery type used in portable electronic devices such as cell phones, computers and more recently their application in full electric vehicles (EV). Li-ion batteries have many advantages over the traditional rechargeable systems (Pb-acid and Ni-MH) such as their higher energy density, low self-discharge, long capacity cycle life and relatively maintenance free. Due to their commercial advantages, a lot of research is done in developing new novel Li-ion electrode materials, improving existing ones and to reduce manufacturing costs in order to make them more cost effective in their applications. This study looked at the cathode material chemistry that has a typical spinel manganese oxide (LiMn2O4) type structure. For comparison the study also considered the influence of doping the phase with various metals such as Al, Mg, Co and Ni that were made as precursors using various carboxylic acids (Citric, Ascorbic, Succinic and Poly-acrylic acid) from a sol-gel process. Traditional batch methods of synthesizing the electrode material is costly and do not necessarily provide optimized electrochemical performance. Alternative continuous less energy intensive methods would help reduce the costs of the preparation of the electrode materials. This study investigated the influence of two synthesis techniques on the materials physical and electrochemical characteristics. These synthesis methods included the use of a typical batch sol-gel method and the continuous spray-drying technique. The spinel materials were prepared and characterized by Powder X-Ray Diffraction (PXRD) to confirm the formation of various phases during the synthesis process. In addition, in-situ PXRD techniques were used to track the phase changes that occurred in the typical batch synthesis process from a sol-gel mixture to the final crystalline spinel oxide. The materials were also characterized by thermal gravimetric analysis (TGA), whereby the materials decomposition mechanisms were observed as the precursor was gradually heated to the final oxide. These synthesized materials prepared under various conditions were then used to build suitable Li-ion coin type of cells, whereby their electrochemical properties were tested by simple capacity tests and electrochemical impedance spectroscopy (EIS). EIS measurements were done on the built cells with the various materials at various charge voltages. TG analysis showed that the materials underwent multiple decomposition steps upon heating for the doped lithium manganese oxides, whereas the undoped oxide showed only a single decomposition step. The results showed that all the materials achieved their weight loss below 400 °C, and that the final spinel oxide had already formed. The in-situ PXRD analysis showed the progression of the phase transitions where certain of the materials changed from a crystalline precursor to an amorphous intermediate phase and then finally to the spinel cathode oxide (Li1.03Mg0.2Mn1.77O4, and LiCo1.09Mn0.91O4). For other materials, the precursor would start as an amorphous phase, and then upon heating, convert into an impure intermediate phase (Mn2O3) before forming the final spinel oxide (Li1.03Mn1.97O4 and LiNi0.5Mn1.5O4). The in-situ study also showed the increases in the materials respective lattice parameters of the crystalline unit cells upon heating and the significant increases in their crystallite sizes when heated above 600 °C. Hence the results implied that a type of sintering of the particles would occur at temperatures above 600 °C, thereby increasing the respective crystallite size. The study showed that the cathode active materials made by the sol-gel spray-drying method would give a material that had a significantly larger surface area and a smaller crystallite size when compared to the materials made by the batch process. The electrochemical analysis showed that there was only a slight increase in the discharge capacities of the cells made with the spray-drying technique when compared to the cells made with the materials from the batch sol-gel technique. Whereas, the EIS study showed that there were distinct differences in the charging behavior of the cells made with the various materials using different synthesis techniques. The EIS results showed that there was a general decrease in the cells charge transfer resistance (Rct) as the charge potential increased regardless of the synthesis method used for the various materials. The results also showed that the lithium-ion diffusion coefficient (DLi) obtained from EIS measurements were in most of the samples higher for the cathode materials that had a larger surface area. This implied that the Li-ion could diffuse at a faster rate through the bulk material. The study concluded that by optimizing the synthesis process in terms of the careful control of the thermal parameters, the Li-ion batteries‟ cathode active material of the manganese spinel type could be optimized and be manufactured by using a continuous flow micro spray process.
- Full Text:
- Date Issued: 2016
An overview of language policy implementation in the City of Tswane Metropolitan Municipality with a focus on translation as an activity of language policy implementation
- Seshoka, Keaobaka Omphile Precious
- Authors: Seshoka, Keaobaka Omphile Precious
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/932 , vital:20004
- Description: The South African Municipality Systems Act (2000) states that language should not act as a barrier of access for citizens with no or limited proficiency in English to municipal services, or in ensuring the right of citizens to participate in, and contribute to the social, cultural, intellectual, economic and political life of South African society. In that regard, it recommends that South African municipalities develop a culture of public participation by providing services in a language preferred and used by citizens within their municipality through translation, amongst other things. This study examines how the translation services, as articulated in the language policy and plan of the City of Tshwane Metropolitan Municipality, is used as a language implementation strategy and in facilitating public participation. It further assesses the quality of the translated information accessed by the different residents of the City of Tshwane Metropolitan Municipality against theories of translation appraisal. The main focus area of this research is on extent of the use of translation as an activity of corpus planning, to facilitate language policy implementation in the City of Tshwane Municipality to enable better public participation. It is hoped that the study will be able to give policy makers and those tasked with implementation, especially at government municipalities‘ strategies to assess and determine the state of translation services to improve functionality, quality and the extent to which translation activities contribute to corpus planning.
- Full Text:
- Date Issued: 2016
- Authors: Seshoka, Keaobaka Omphile Precious
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/932 , vital:20004
- Description: The South African Municipality Systems Act (2000) states that language should not act as a barrier of access for citizens with no or limited proficiency in English to municipal services, or in ensuring the right of citizens to participate in, and contribute to the social, cultural, intellectual, economic and political life of South African society. In that regard, it recommends that South African municipalities develop a culture of public participation by providing services in a language preferred and used by citizens within their municipality through translation, amongst other things. This study examines how the translation services, as articulated in the language policy and plan of the City of Tshwane Metropolitan Municipality, is used as a language implementation strategy and in facilitating public participation. It further assesses the quality of the translated information accessed by the different residents of the City of Tshwane Metropolitan Municipality against theories of translation appraisal. The main focus area of this research is on extent of the use of translation as an activity of corpus planning, to facilitate language policy implementation in the City of Tshwane Municipality to enable better public participation. It is hoped that the study will be able to give policy makers and those tasked with implementation, especially at government municipalities‘ strategies to assess and determine the state of translation services to improve functionality, quality and the extent to which translation activities contribute to corpus planning.
- Full Text:
- Date Issued: 2016
Anti-diabetic and phytochemical analysis of sutherlandia frutescens extracts
- Authors: Adefuye, Ogheneochuko Janet
- Date: 2016
- Subjects: Medicinal plants -- Africa , Traditional medicine -- Africa , Herbs -- Therapeutic use -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/3549 , vital:20441
- Description: In Africa, the importance of medicinal plants in folklore medicine and their contribution to primary healthcare is well recognized. Across the continent, local herbal mixtures still provide the only therapeutic option for about 80% of the population. The vast floral diversity and the intrinsic ethnobotanical knowledge has been the backbone of localized traditional herbal medical practices. In Africa, an estimated 5400 of the 60000 described plant taxa possess over 16300 therapeutic uses. Similarly, with a therapeutic flora comprising of approximately 650 species, herbal medical practitioners in South Africa, make use of a plethora of plants to treat different human diseases and infections. Over the years, studies have identified numerous plant species with potential against chronic metabolic diseases including type 2 diabetes mellitus (T2DM). Globally, the incidence and prevalence of T2DM have reached epidemic proportions affecting people of all ages, nationalities and ethnicity. Considered the fourth leading cause of deaths by disease, T2DM is a global health crisis with an estimated diagnosis and mortality frequency of 1 every 5 seconds and 1 every 7 seconds respectively. Though the exact pathophysiology of T2DM is not entirely understood, initial peripheral insulin resistance in adipose tissue, liver, and skeletal muscle with subsequent pancreatic β-cell dysfunction resulting from an attempt to compensate for insulin resistance is a common feature of the disease. The current approach to treating T2DM is the use of oral antidiabetic agents (OAAs), insulin, and incretin-based drugs in an attempt to achieve glycaemic control and maintain glucose homeostasis. However, conventional anti-T2DM drugs have been shown to have limited efficacies and serious adverse effects. Hence, the need for newer, more efficacious and safer anti-T2DM agents. Sutherlandia frutescens subsp. microphylla is a flowering shrub of the pea family (Fabaceae/Leguminaceae) found mainly in the Western Cape and Karoo regions of Southern Africa. Concoctions of various parts of the plant are used in the management of different ailments including T2DM. However, despite extensive biological and pharmacological studies, few analyses exist of the chemical constituents of S. frutescens and no Triple Time of Flight Liquid Chromatography with Mass Spectrometry (Triple TOF LC/MS/MS) analysis has been performed. The initial aim of this study was to investigate the phytochemical profile of hot aqueous, cold aqueous, 80% ethanolic, 100% ethanolic, 80% methanolic and 100% methanolic extracts of a single source S. frutescens plant material using colorimetric and spectrophotometric analysis. The hot aqueous extractant was found to be the best extractant for S. frutescens, yielding 1.99 g of crude extract from 16 g fresh powdered plant material. This data suggests that application of heat and water as the extractant (hot aqueous) could play a vital role in extraction of bioactive compounds from S. frutescens and also justifies the traditional use of a tea infusion of S. frutescens. Colorimetric analysis revealed the presence of flavonoids, flavonols, tannins, and phenols in all extracts with varying intensity. The organic extracts 100% methanol, 80% and 100% ethanol exhibited high color intensity (+++) for flavonoids and flavonols respectively, while all the extracts exhibited a moderate color intensity (++) for tannins and phenols. Spectrophotometric analysis of S. frutescens extracts revealed that all the organic extracts contained a significantly higher concentration (in mg/g of extract) of flavonols and tannins when compared to the aqueous extracts. All extracts contained approximately equal levels of phenols. These data confirm the presence of all four groups of bioactive phytocompounds in the S. frutescens extracts used in this study, and also confirm that different solvent extractants possess the capability to differentially extract specific groups of phytocompounds. in individual extracts. Further comparison of these compounds with online databases of anti-diabetic phytocompounds led to the preliminary identification of 10 possible anti-diabetic compounds; α-Pinene, Limonene, Sabinene, Carvone, Myricetin, Rutin, Stigmasterol, Emodin, Sarpagine and Hypoglycin B in crude and solid phase extraction (SPE) fractions of S. frutesecens. Furthermore, using two hepatic cell lines (Chang and HepG2) as an in-vtro model system, the anti-T2DM properties of crude aqueous and organic extracts of S. frutescents was investigated and compared. Both aqueous and organic extracts of S. frutescens were found to decrease gluconeogenesis, increase glucose uptake and decrease lipid accumulation (Triacylglycerol, Diacylglycerol, and Monoacylglycerol) in Chang and HepG2 hepatic cell cultures made insulin resistant (IR) following exposure to high concentration of insulin and fructose. Using real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the aqueous and organic extracts of S. frutescens were confirmed to regulate the expression of Vesicle-associated membrane protein 3 (VAMP3), Mitogen-activated protein kinase 8 (MAPK8), and Insulin receptor substrate 1 (IRS1) in insulin resistant hepatic cells. IR-mediated downregulation of VAMP3, MAPK8, and IRS1 mRNA in IR HepG2 hepatic cell cultures was reversed in the presence of aqueous and organic extracts of S. frutescens. The hot aqueous extract displayed the highest activity in all the assays, while all the organic extracts displayed similar potency. In conclusion, this study reports that aqueous and organic extracts of S. frutescens possess numerous anti-diabetic compounds that can be further investigated for the development of new, more efficacious and less toxic anti-diabetic agents. The presence of multiple compounds in a single extract does suggest a synergistic or combinatorial therapeutic effect. These findings support the burgeoning body of in-vivo and in-vitro literature evidence on the anti-diabetic properties of S. frutescens and its use in folklore medicine.
- Full Text:
- Date Issued: 2016
- Authors: Adefuye, Ogheneochuko Janet
- Date: 2016
- Subjects: Medicinal plants -- Africa , Traditional medicine -- Africa , Herbs -- Therapeutic use -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/3549 , vital:20441
- Description: In Africa, the importance of medicinal plants in folklore medicine and their contribution to primary healthcare is well recognized. Across the continent, local herbal mixtures still provide the only therapeutic option for about 80% of the population. The vast floral diversity and the intrinsic ethnobotanical knowledge has been the backbone of localized traditional herbal medical practices. In Africa, an estimated 5400 of the 60000 described plant taxa possess over 16300 therapeutic uses. Similarly, with a therapeutic flora comprising of approximately 650 species, herbal medical practitioners in South Africa, make use of a plethora of plants to treat different human diseases and infections. Over the years, studies have identified numerous plant species with potential against chronic metabolic diseases including type 2 diabetes mellitus (T2DM). Globally, the incidence and prevalence of T2DM have reached epidemic proportions affecting people of all ages, nationalities and ethnicity. Considered the fourth leading cause of deaths by disease, T2DM is a global health crisis with an estimated diagnosis and mortality frequency of 1 every 5 seconds and 1 every 7 seconds respectively. Though the exact pathophysiology of T2DM is not entirely understood, initial peripheral insulin resistance in adipose tissue, liver, and skeletal muscle with subsequent pancreatic β-cell dysfunction resulting from an attempt to compensate for insulin resistance is a common feature of the disease. The current approach to treating T2DM is the use of oral antidiabetic agents (OAAs), insulin, and incretin-based drugs in an attempt to achieve glycaemic control and maintain glucose homeostasis. However, conventional anti-T2DM drugs have been shown to have limited efficacies and serious adverse effects. Hence, the need for newer, more efficacious and safer anti-T2DM agents. Sutherlandia frutescens subsp. microphylla is a flowering shrub of the pea family (Fabaceae/Leguminaceae) found mainly in the Western Cape and Karoo regions of Southern Africa. Concoctions of various parts of the plant are used in the management of different ailments including T2DM. However, despite extensive biological and pharmacological studies, few analyses exist of the chemical constituents of S. frutescens and no Triple Time of Flight Liquid Chromatography with Mass Spectrometry (Triple TOF LC/MS/MS) analysis has been performed. The initial aim of this study was to investigate the phytochemical profile of hot aqueous, cold aqueous, 80% ethanolic, 100% ethanolic, 80% methanolic and 100% methanolic extracts of a single source S. frutescens plant material using colorimetric and spectrophotometric analysis. The hot aqueous extractant was found to be the best extractant for S. frutescens, yielding 1.99 g of crude extract from 16 g fresh powdered plant material. This data suggests that application of heat and water as the extractant (hot aqueous) could play a vital role in extraction of bioactive compounds from S. frutescens and also justifies the traditional use of a tea infusion of S. frutescens. Colorimetric analysis revealed the presence of flavonoids, flavonols, tannins, and phenols in all extracts with varying intensity. The organic extracts 100% methanol, 80% and 100% ethanol exhibited high color intensity (+++) for flavonoids and flavonols respectively, while all the extracts exhibited a moderate color intensity (++) for tannins and phenols. Spectrophotometric analysis of S. frutescens extracts revealed that all the organic extracts contained a significantly higher concentration (in mg/g of extract) of flavonols and tannins when compared to the aqueous extracts. All extracts contained approximately equal levels of phenols. These data confirm the presence of all four groups of bioactive phytocompounds in the S. frutescens extracts used in this study, and also confirm that different solvent extractants possess the capability to differentially extract specific groups of phytocompounds. in individual extracts. Further comparison of these compounds with online databases of anti-diabetic phytocompounds led to the preliminary identification of 10 possible anti-diabetic compounds; α-Pinene, Limonene, Sabinene, Carvone, Myricetin, Rutin, Stigmasterol, Emodin, Sarpagine and Hypoglycin B in crude and solid phase extraction (SPE) fractions of S. frutesecens. Furthermore, using two hepatic cell lines (Chang and HepG2) as an in-vtro model system, the anti-T2DM properties of crude aqueous and organic extracts of S. frutescents was investigated and compared. Both aqueous and organic extracts of S. frutescens were found to decrease gluconeogenesis, increase glucose uptake and decrease lipid accumulation (Triacylglycerol, Diacylglycerol, and Monoacylglycerol) in Chang and HepG2 hepatic cell cultures made insulin resistant (IR) following exposure to high concentration of insulin and fructose. Using real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the aqueous and organic extracts of S. frutescens were confirmed to regulate the expression of Vesicle-associated membrane protein 3 (VAMP3), Mitogen-activated protein kinase 8 (MAPK8), and Insulin receptor substrate 1 (IRS1) in insulin resistant hepatic cells. IR-mediated downregulation of VAMP3, MAPK8, and IRS1 mRNA in IR HepG2 hepatic cell cultures was reversed in the presence of aqueous and organic extracts of S. frutescens. The hot aqueous extract displayed the highest activity in all the assays, while all the organic extracts displayed similar potency. In conclusion, this study reports that aqueous and organic extracts of S. frutescens possess numerous anti-diabetic compounds that can be further investigated for the development of new, more efficacious and less toxic anti-diabetic agents. The presence of multiple compounds in a single extract does suggest a synergistic or combinatorial therapeutic effect. These findings support the burgeoning body of in-vivo and in-vitro literature evidence on the anti-diabetic properties of S. frutescens and its use in folklore medicine.
- Full Text:
- Date Issued: 2016
Aquatic–terrestrial trophic linkages via riverine invertebrates in a South African catchment
- Authors: Moyo, Sydney
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54427 , vital:26564
- Description: Rivers play a vital role in human livelihoods and are likely to undergo substantial alteration due to climate and land use changes from an increasing human population. Mitigating the pressures facing rivers in the world requires scientists and environmental managers to understand the ecological mechanisms, and ultimately the strength, of connections between ecosystems. This understanding of connections between adjacent habitats will enable environmental managers to predict the consequences of perturbing these linkages in the future. In this thesis, aquatic-terrestrial linkages in rivers were investigated using ecologically meaningful variables including abundances, biomasses, stable isotopes and fatty acids. This study is part of a larger project entitled “Connectivity through allochthony: reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa”, in which a team of researchers assessed a variety of pathways connecting riverine and estuarine systems to land within a catchment in the Eastern Cape, South Africa. I conceptualised the flow of energy within a temperate southern hemisphere river (the Kowie River) within theoretical models of energy flow such as the River Continuum Concept (RCC; presents lotic systems as being longitudinally linked with food webs in shaded headwaters being principally driven by allochthonous energy, with the addition of autochthonous food as a minor carbon source in the lower reaches) and the Riverine Productivity Model (RPM; proposes consumers derive most of their energy from local production of phytoplankton, benthic algae and aquatic plants, as well as directly from riparian zones via terrestrial leaf litter). Using the RCC as a starting point, I collected macroinvertebrates (September 2012 to May 2013) along a longitudinal gradient and grouped them into functional feeding groups (FFGs). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50 – 83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was ≤ 10% across all sites and seasons). The changes in relative abundances of different FFGs did not follow predictions of the RCC along the longitudinal gradient, as there were no correlations of community structure with some physical attributes (stream width, canopy cover, distance of river) that changed along the river continuum. However, FFG abundances were related to water velocity, total dissolved solids and canopy cover. Broadly, the Kowie River data showed that changes in relative abundances of FFGs along the river continuum could not be explained by changes in physical attributes alone, and may be highly influenced by the availability of food and the chemistry of the stream. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes was used to estimate the contributions of algal and land-based production to consumers over space (six sites) and time (November 2012 to September 2013). Carbon contributions determined by the use of mixing models (Stable Isotope Analysis in R) revealed that consumers in the headwater assimilated mainly terrestrially-derived organic matter, with consumers in the middle and lower reaches assimilating autochthonous basal resources (macrophytes and algae). The findings from this river supported aspects of the RCC (at the headwaters; terrestrial organic matter made up 41% of consumer diets), but overall the data supported the predictions of the RPM (local production made the highest contributions of 50 – 86% to all FFGs across all seasons). The carbon isotopes of consumers and their food sources changed substantially every season, indicating that samples of food sources and consumers should be analysed many times throughout the year to capture that variability and to ensure that ephemeral components of the food web are not missed. To validate the findings from the isotope data, fatty acids were used as complementary tracers to determine the contributions of algal versus terrestrial organic matter to the consumers. Fatty acid tracers for terrestrial (Ʃω3/Ʃω6; 18:2ω6; 18:3ω3) vs aquatic (Ʃω3/Ʃω6; 20:5ω3) sources corroborated the findings from the isotope data set, as the mean ratio of Ʃω3/Ʃω6 in consumers was less than one at the headwaters (indicating allochthony), while middle and lower reaches were associated with Ʃω3/Ʃω6 > 1 (indicating autochthony). In addition to the tracer and FFG analyses for examining trophic connections between land and river, the bidirectional exchange of organisms between the riparian zone and the river was assessed using floating pyramidal traps (to measure emergence) and pan traps (for infalling invertebrates) placed at different sites in the river and the biomass in each trap was determined. The exchanges were variable over space and time, with emergence peaking in summer (169 to 1402 mg m-2 day-1) and declining in winter (3 to 28 mg m-2 day-1). Similarly, infalling invertebrates increased in summer (413 to 679 mg m-2 day-1) and declined in winter (11 to 220 mg m-2 day-1). Biomass measurements are indications of quantity that ignore nutritional quality, so I determined the bidirectional flow of invertebrates using absolute concentrations of physiologically important biochemical compounds (essential and polyunsaturated fatty acids). The fluxes of emergent and infalling arthropods peaked in summer (emergence = 0.3 to 18 mg m-2 day-1 and terrestrial infall = 0.3 to 3 mg m-2 day-1) and declined in winter (emergence = 0.01 to 0.51 mg m-2 day-1 and terrestrial infall = 0.01 to 0.03 mg m-2 day-1). However, during some seasons, no significant differences in polyunsaturated fatty acid flux in either direction were observed; this finding indicated the balance of reciprocal subsidisation via reciprocal flows of animals. Factors such as air temperature and algal productivity affected the reciprocal flows between adjacent habitats, with algal productivity being positively related to emergence while air temperature was positively correlated to infalling terrestrial invertebrates. This research enhances the growing body of literature on the function of riverine systems and offers some invaluable information on the flow of energy and the role played by invertebrates in translocating nutrients from terrestrial systems to aquatic systems and vice versa. This study unifies the concepts of the RCC and RPM and shows that these concepts are not limited only to large rivers, but are applicable to small southern temperate rivers too. However, some tenets of the theoretical models were challenged. For example, it challenges the proposition by the RCC that the fine particulate organic matter leaked from upstream breakdown of coarse particulate organic matter is predominantly allochthonous. Additionally, this study showed that in the headwaters, the RPM underestimated the role of autochthony. Overall, the results showed that the Kowie River and its riparian area are intrinsically connected. Once we understand the mechanisms controlling connections and subsidies across ecotones, we can then start to predict the consequences of disruptions to these connections by climate change and/or land use changes. To make predictions about future perturbations to rivers and riparian zones, studies like this, which considers the form and magnitude of subsidies, are needed to provide baseline information. Algal resources (e.g. epiphyton), macrophytes, riparian plants, terrestrial organisms and aquatic organisms all contributed to aquatic and terrestrial linkages in the Kowie River; therefore, it is important to conserve the different components of these ecosystems.
- Full Text:
- Date Issued: 2016
- Authors: Moyo, Sydney
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54427 , vital:26564
- Description: Rivers play a vital role in human livelihoods and are likely to undergo substantial alteration due to climate and land use changes from an increasing human population. Mitigating the pressures facing rivers in the world requires scientists and environmental managers to understand the ecological mechanisms, and ultimately the strength, of connections between ecosystems. This understanding of connections between adjacent habitats will enable environmental managers to predict the consequences of perturbing these linkages in the future. In this thesis, aquatic-terrestrial linkages in rivers were investigated using ecologically meaningful variables including abundances, biomasses, stable isotopes and fatty acids. This study is part of a larger project entitled “Connectivity through allochthony: reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa”, in which a team of researchers assessed a variety of pathways connecting riverine and estuarine systems to land within a catchment in the Eastern Cape, South Africa. I conceptualised the flow of energy within a temperate southern hemisphere river (the Kowie River) within theoretical models of energy flow such as the River Continuum Concept (RCC; presents lotic systems as being longitudinally linked with food webs in shaded headwaters being principally driven by allochthonous energy, with the addition of autochthonous food as a minor carbon source in the lower reaches) and the Riverine Productivity Model (RPM; proposes consumers derive most of their energy from local production of phytoplankton, benthic algae and aquatic plants, as well as directly from riparian zones via terrestrial leaf litter). Using the RCC as a starting point, I collected macroinvertebrates (September 2012 to May 2013) along a longitudinal gradient and grouped them into functional feeding groups (FFGs). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50 – 83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was ≤ 10% across all sites and seasons). The changes in relative abundances of different FFGs did not follow predictions of the RCC along the longitudinal gradient, as there were no correlations of community structure with some physical attributes (stream width, canopy cover, distance of river) that changed along the river continuum. However, FFG abundances were related to water velocity, total dissolved solids and canopy cover. Broadly, the Kowie River data showed that changes in relative abundances of FFGs along the river continuum could not be explained by changes in physical attributes alone, and may be highly influenced by the availability of food and the chemistry of the stream. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes was used to estimate the contributions of algal and land-based production to consumers over space (six sites) and time (November 2012 to September 2013). Carbon contributions determined by the use of mixing models (Stable Isotope Analysis in R) revealed that consumers in the headwater assimilated mainly terrestrially-derived organic matter, with consumers in the middle and lower reaches assimilating autochthonous basal resources (macrophytes and algae). The findings from this river supported aspects of the RCC (at the headwaters; terrestrial organic matter made up 41% of consumer diets), but overall the data supported the predictions of the RPM (local production made the highest contributions of 50 – 86% to all FFGs across all seasons). The carbon isotopes of consumers and their food sources changed substantially every season, indicating that samples of food sources and consumers should be analysed many times throughout the year to capture that variability and to ensure that ephemeral components of the food web are not missed. To validate the findings from the isotope data, fatty acids were used as complementary tracers to determine the contributions of algal versus terrestrial organic matter to the consumers. Fatty acid tracers for terrestrial (Ʃω3/Ʃω6; 18:2ω6; 18:3ω3) vs aquatic (Ʃω3/Ʃω6; 20:5ω3) sources corroborated the findings from the isotope data set, as the mean ratio of Ʃω3/Ʃω6 in consumers was less than one at the headwaters (indicating allochthony), while middle and lower reaches were associated with Ʃω3/Ʃω6 > 1 (indicating autochthony). In addition to the tracer and FFG analyses for examining trophic connections between land and river, the bidirectional exchange of organisms between the riparian zone and the river was assessed using floating pyramidal traps (to measure emergence) and pan traps (for infalling invertebrates) placed at different sites in the river and the biomass in each trap was determined. The exchanges were variable over space and time, with emergence peaking in summer (169 to 1402 mg m-2 day-1) and declining in winter (3 to 28 mg m-2 day-1). Similarly, infalling invertebrates increased in summer (413 to 679 mg m-2 day-1) and declined in winter (11 to 220 mg m-2 day-1). Biomass measurements are indications of quantity that ignore nutritional quality, so I determined the bidirectional flow of invertebrates using absolute concentrations of physiologically important biochemical compounds (essential and polyunsaturated fatty acids). The fluxes of emergent and infalling arthropods peaked in summer (emergence = 0.3 to 18 mg m-2 day-1 and terrestrial infall = 0.3 to 3 mg m-2 day-1) and declined in winter (emergence = 0.01 to 0.51 mg m-2 day-1 and terrestrial infall = 0.01 to 0.03 mg m-2 day-1). However, during some seasons, no significant differences in polyunsaturated fatty acid flux in either direction were observed; this finding indicated the balance of reciprocal subsidisation via reciprocal flows of animals. Factors such as air temperature and algal productivity affected the reciprocal flows between adjacent habitats, with algal productivity being positively related to emergence while air temperature was positively correlated to infalling terrestrial invertebrates. This research enhances the growing body of literature on the function of riverine systems and offers some invaluable information on the flow of energy and the role played by invertebrates in translocating nutrients from terrestrial systems to aquatic systems and vice versa. This study unifies the concepts of the RCC and RPM and shows that these concepts are not limited only to large rivers, but are applicable to small southern temperate rivers too. However, some tenets of the theoretical models were challenged. For example, it challenges the proposition by the RCC that the fine particulate organic matter leaked from upstream breakdown of coarse particulate organic matter is predominantly allochthonous. Additionally, this study showed that in the headwaters, the RPM underestimated the role of autochthony. Overall, the results showed that the Kowie River and its riparian area are intrinsically connected. Once we understand the mechanisms controlling connections and subsidies across ecotones, we can then start to predict the consequences of disruptions to these connections by climate change and/or land use changes. To make predictions about future perturbations to rivers and riparian zones, studies like this, which considers the form and magnitude of subsidies, are needed to provide baseline information. Algal resources (e.g. epiphyton), macrophytes, riparian plants, terrestrial organisms and aquatic organisms all contributed to aquatic and terrestrial linkages in the Kowie River; therefore, it is important to conserve the different components of these ecosystems.
- Full Text:
- Date Issued: 2016
Assessing the impact of climate change on mangrove crabs: the role of ontogenetic macrophysiology and settlement in the persistence of central and marginal populations
- Authors: Mostert, Bruce Petrus
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/826 , vital:19994
- Description: After a brief respite in the mid to late 20th century, macro physiology has come to the fore in elucidating large scale ecological patterns and processes as physiological assumptions often form the backbone of many predictive theories associated with species distributions. Critically, macro physiological patterns are valuable in explaining physiological variation across multiple scales and provide insights into the effects of climate change on populations spanning a wide range of latitudes. This can assist in predicting possible distribution expansions, contractions or shifts in light of current climate change scenarios. From this perspective, investigating intra- and inter-specific physiological responses to environmental stress may contribute to better understanding and predicting the effects of climate change on geographical ranges. Further, investigating the physiological effects to environmental stresses across ontogenetic stages allows for the identification of weak links within the lifecycle of a species. Additionally, determining settlement characteristics along a latitudinal cline provides integrated indications of the sustainability of populations, highlighting vulnerable regions in terms of repopulation of viable habitats. In this context, the present study aimed at establishing how temperature, in a physiological context, may affect reproductive biology of two species of mangrove crab, Perisesarma guttatum and Uca urvillei at the centre (Kenya) and edge (South Africa) of their distributional range along the east coast of Africa and highlight possible consequences for range distributions. A third species, Neosarmatium africanum, only in South Africa, was included to provide additional interspecies comparisons. Furthermore, settlement characteristics of brachyuran populations at the centre and edge of their distributional range were considered in order to determine how settlement may contribute to population persistence. Physiological investigations at the centre and edge of distributional range and across ontogenetic stages (larvae, stage 2 and 4 embryos, non-gravid and gravid females) under the concept of oxygen and capacity limitation of thermal tolerance (OCLTT), revealed that, for both species, populations at the centre of their distribution (Kenya) were generally more robust to increasing temperatures and generally displayed greater physiological stability with increasing temperatures compared to their conspecifics in South Africa. Variability in physiological robustness between regions, did however, differ among ontogenetic stages and species but, overall, were evident throughout. Within and between regions, adaptation to oxygen extraction in both milieus (air or water) was displayed for present temperature conditions but aerial respiration largely alleviated increased thermal stress due to overcoming the limitations of reduced oxygen availability and diffusiveness in water for all bimodal ontogenetic stages. Brooding eggs proved to be a physiologically critical process with either heighted oxygen consumption for gravid females or collapse of physiological processes demonstrated by supressed oxygen consumption. The physiological cost of brooding eggs, referred to as maternal costs, was reflected in in both Perisesarma guttatum and Uca urvillei where, in most cases, maternal costs were negative. Again, aerial respiration was able to alleviated increased thermal stress, as shown by positive maternal costs indicating sustained maternal care, but this mechanism was species and regionally specific. Settlement patterns differed between the edge and centre of distribution of the species studied. This difference was predominantly driven by zonal preference within the mangal and/or effects of new and full moon (lunar phase). Overall, settlement dynamics were more widely variable in South Africa, both spatially and temporally, than in Kenya. Finally, empirical physiological data from ontogenetic stages present during the reproductive process (early and late stage embryos) and from non-gravid and gravid females were used in conjunction with data mined from the existing literature to parameterise an individual based model designed to simulate reproductive output at the centre and edge of distribution of Perisesarma guttatum. Physiological data indicate that, in terms of reproductive output across increasing temperatures, populations based at the centre of their distribution presently outperform their counterparts at the edge of the species’ distribution, but reproductive output stagnated as temperature rose. Edge of distribution populations consistently increased reproductive output with increasing temperatures to eventually outperform centre of distribution populations at higher simulated temperatures. Overall, results of the physiological and settlement studies suggest that with increased climate change there may be a contraction of distributional range of the study species from high latitudes to low latitudes, contrary to general poleward shifts/migrations seen in most species, with possible contractions of the entire ecosystem mirroring the disappearance of keystone mangrove macrofauna.
- Full Text:
- Date Issued: 2016
- Authors: Mostert, Bruce Petrus
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/826 , vital:19994
- Description: After a brief respite in the mid to late 20th century, macro physiology has come to the fore in elucidating large scale ecological patterns and processes as physiological assumptions often form the backbone of many predictive theories associated with species distributions. Critically, macro physiological patterns are valuable in explaining physiological variation across multiple scales and provide insights into the effects of climate change on populations spanning a wide range of latitudes. This can assist in predicting possible distribution expansions, contractions or shifts in light of current climate change scenarios. From this perspective, investigating intra- and inter-specific physiological responses to environmental stress may contribute to better understanding and predicting the effects of climate change on geographical ranges. Further, investigating the physiological effects to environmental stresses across ontogenetic stages allows for the identification of weak links within the lifecycle of a species. Additionally, determining settlement characteristics along a latitudinal cline provides integrated indications of the sustainability of populations, highlighting vulnerable regions in terms of repopulation of viable habitats. In this context, the present study aimed at establishing how temperature, in a physiological context, may affect reproductive biology of two species of mangrove crab, Perisesarma guttatum and Uca urvillei at the centre (Kenya) and edge (South Africa) of their distributional range along the east coast of Africa and highlight possible consequences for range distributions. A third species, Neosarmatium africanum, only in South Africa, was included to provide additional interspecies comparisons. Furthermore, settlement characteristics of brachyuran populations at the centre and edge of their distributional range were considered in order to determine how settlement may contribute to population persistence. Physiological investigations at the centre and edge of distributional range and across ontogenetic stages (larvae, stage 2 and 4 embryos, non-gravid and gravid females) under the concept of oxygen and capacity limitation of thermal tolerance (OCLTT), revealed that, for both species, populations at the centre of their distribution (Kenya) were generally more robust to increasing temperatures and generally displayed greater physiological stability with increasing temperatures compared to their conspecifics in South Africa. Variability in physiological robustness between regions, did however, differ among ontogenetic stages and species but, overall, were evident throughout. Within and between regions, adaptation to oxygen extraction in both milieus (air or water) was displayed for present temperature conditions but aerial respiration largely alleviated increased thermal stress due to overcoming the limitations of reduced oxygen availability and diffusiveness in water for all bimodal ontogenetic stages. Brooding eggs proved to be a physiologically critical process with either heighted oxygen consumption for gravid females or collapse of physiological processes demonstrated by supressed oxygen consumption. The physiological cost of brooding eggs, referred to as maternal costs, was reflected in in both Perisesarma guttatum and Uca urvillei where, in most cases, maternal costs were negative. Again, aerial respiration was able to alleviated increased thermal stress, as shown by positive maternal costs indicating sustained maternal care, but this mechanism was species and regionally specific. Settlement patterns differed between the edge and centre of distribution of the species studied. This difference was predominantly driven by zonal preference within the mangal and/or effects of new and full moon (lunar phase). Overall, settlement dynamics were more widely variable in South Africa, both spatially and temporally, than in Kenya. Finally, empirical physiological data from ontogenetic stages present during the reproductive process (early and late stage embryos) and from non-gravid and gravid females were used in conjunction with data mined from the existing literature to parameterise an individual based model designed to simulate reproductive output at the centre and edge of distribution of Perisesarma guttatum. Physiological data indicate that, in terms of reproductive output across increasing temperatures, populations based at the centre of their distribution presently outperform their counterparts at the edge of the species’ distribution, but reproductive output stagnated as temperature rose. Edge of distribution populations consistently increased reproductive output with increasing temperatures to eventually outperform centre of distribution populations at higher simulated temperatures. Overall, results of the physiological and settlement studies suggest that with increased climate change there may be a contraction of distributional range of the study species from high latitudes to low latitudes, contrary to general poleward shifts/migrations seen in most species, with possible contractions of the entire ecosystem mirroring the disappearance of keystone mangrove macrofauna.
- Full Text:
- Date Issued: 2016
Assessment of fluctuating asymmetry as an indicator of water quality stress in South Africa
- Authors: Holland, Alexandra Jennifer
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/430 , vital:19958
- Description: South Africa’s freshwater resources are facing numerous water quality challenges and need to be protected from degradation and pollution by appropriate management strategies as they are a limited and shared resource. The South African Scoring System (SASS5), which assesses macroinvertebrate communities at family level, is used in routine monitoring of riverine ecosystems in South Africa. Assessing the condition of these ecosystems is limited as SASS5 does not allow for changes at lower levels of biological organisation to be detected. Fluctuating asymmetry (FA) - small random deviations from perfect symmetry - is considered a direct measure of developmental instability. This phenotypical response results from numerous internal and external factors and has a low level of heritability. FA is based on sound scientific principles, easy to measure, biologically robust and cost-effective. It reflects synergistic interactions between stressors and provides an integrated measure of several anthropogenic stresses, which strengthens the assertion that FA is an environmental indicator of water quality stress, and can potentially be used to detect stress in populations before irreversible effects manifest. FA responses were investigated by (1) exposing freshwater shrimp to increasing concentrations of cadmium chloride in a long-term experiment and (2) comparing FA responses to water quality changes and macroinvertebrate community responses in two case studies (Kwazulu-Natal and Limpopo Province) in South Africa. Although no consistent concentration-response curve could be established, this study suggests that FA responses can be used as a sublethal endpoint in exposure experiments. Determining water quality parameters causing FA responses was not possible in field collected freshwater shrimp in either case study. Although FA did not specifically respond to any of the measured water quality parameters identified in the case studies, it has potential as a general indicator of water quality stress in freshwater shrimp. This study shows that FA responses are potentially more sensitive than macroinvertebrate community responses to pollution since it is not affected by habitat. Since FA has the potential to be a general indicator of population quality, particularly where there are natural habitat differences, it can be useful at the level of biomonitoring required for routine basic river status assessments in South Africa. However, in order for FA to become a robust tool that can be used routinely in conjunction with SASS5 more research is required.
- Full Text:
- Date Issued: 2016
- Authors: Holland, Alexandra Jennifer
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/430 , vital:19958
- Description: South Africa’s freshwater resources are facing numerous water quality challenges and need to be protected from degradation and pollution by appropriate management strategies as they are a limited and shared resource. The South African Scoring System (SASS5), which assesses macroinvertebrate communities at family level, is used in routine monitoring of riverine ecosystems in South Africa. Assessing the condition of these ecosystems is limited as SASS5 does not allow for changes at lower levels of biological organisation to be detected. Fluctuating asymmetry (FA) - small random deviations from perfect symmetry - is considered a direct measure of developmental instability. This phenotypical response results from numerous internal and external factors and has a low level of heritability. FA is based on sound scientific principles, easy to measure, biologically robust and cost-effective. It reflects synergistic interactions between stressors and provides an integrated measure of several anthropogenic stresses, which strengthens the assertion that FA is an environmental indicator of water quality stress, and can potentially be used to detect stress in populations before irreversible effects manifest. FA responses were investigated by (1) exposing freshwater shrimp to increasing concentrations of cadmium chloride in a long-term experiment and (2) comparing FA responses to water quality changes and macroinvertebrate community responses in two case studies (Kwazulu-Natal and Limpopo Province) in South Africa. Although no consistent concentration-response curve could be established, this study suggests that FA responses can be used as a sublethal endpoint in exposure experiments. Determining water quality parameters causing FA responses was not possible in field collected freshwater shrimp in either case study. Although FA did not specifically respond to any of the measured water quality parameters identified in the case studies, it has potential as a general indicator of water quality stress in freshwater shrimp. This study shows that FA responses are potentially more sensitive than macroinvertebrate community responses to pollution since it is not affected by habitat. Since FA has the potential to be a general indicator of population quality, particularly where there are natural habitat differences, it can be useful at the level of biomonitoring required for routine basic river status assessments in South Africa. However, in order for FA to become a robust tool that can be used routinely in conjunction with SASS5 more research is required.
- Full Text:
- Date Issued: 2016
Assessment of monitoring and evaluation of non-financial performance of provincial departments in the province of the Eastern Cape with special reference to its impact on service delivery
- Authors: Vermaak, Ernest Paul
- Date: 2016
- Subjects: Government productivity -- South Africa -- Eastern Cape -- Evaluation Performance standards -- South Africa -- Eastern Cape -- Evaluation Government accountability -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4571 , vital:28423
- Description: In this research study an investigation was launched into the monitoring and evaluation system that the government introduced to monitor and evaluate the performance information produced by the Provincial Government Departments on the implementation of their annual performance plans. The Government Departments obtain budget approval from the Legislature and submit their three-year performance plans with their budgets. The government realized that service delivery was not improving against the back drop of annually increasing the budgets. The monitoring and evaluation system was introduced to assist the Government Departments with the implementation of their annual performance plans. Monitoring and evaluation serves as a control measure and deviations can be detected from the planned outputs of the Government Departments. Corrective measures must be instituted that will have the effect that the Government Departments meet the targets set in the indicators as approved in the annual performance plans. A literature review was conducted on monitoring and evaluation regarding the ideal manner in which it should be performed. The South African Government introduced a number of discussion documents from the Presidency and National Treasury on monitoring and evaluation. Several authors raised their views on the matter and it was captured in the research study. The methodology followed was based on the Systems Theory and a questionnaire was prepared and circulated amongst Political Office Bearers and Chief Officials in the Provincial Government Departments in the Eastern Cape on the issues that was researched. Interviews were conducted with selected participants to gain clarity on specific issues related to the questionnaire. The official annual report issued by the Auditor General to the Provincial Legislature served as official document in the research study. The data collected from the questionnaire, interviews and official documentation was analyzed and graphs were drawn and deductions were made from the results. Findings and recommendations were made from the data collected and a summary was compiled of the issues raised in the research study.
- Full Text:
- Date Issued: 2016
- Authors: Vermaak, Ernest Paul
- Date: 2016
- Subjects: Government productivity -- South Africa -- Eastern Cape -- Evaluation Performance standards -- South Africa -- Eastern Cape -- Evaluation Government accountability -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4571 , vital:28423
- Description: In this research study an investigation was launched into the monitoring and evaluation system that the government introduced to monitor and evaluate the performance information produced by the Provincial Government Departments on the implementation of their annual performance plans. The Government Departments obtain budget approval from the Legislature and submit their three-year performance plans with their budgets. The government realized that service delivery was not improving against the back drop of annually increasing the budgets. The monitoring and evaluation system was introduced to assist the Government Departments with the implementation of their annual performance plans. Monitoring and evaluation serves as a control measure and deviations can be detected from the planned outputs of the Government Departments. Corrective measures must be instituted that will have the effect that the Government Departments meet the targets set in the indicators as approved in the annual performance plans. A literature review was conducted on monitoring and evaluation regarding the ideal manner in which it should be performed. The South African Government introduced a number of discussion documents from the Presidency and National Treasury on monitoring and evaluation. Several authors raised their views on the matter and it was captured in the research study. The methodology followed was based on the Systems Theory and a questionnaire was prepared and circulated amongst Political Office Bearers and Chief Officials in the Provincial Government Departments in the Eastern Cape on the issues that was researched. Interviews were conducted with selected participants to gain clarity on specific issues related to the questionnaire. The official annual report issued by the Auditor General to the Provincial Legislature served as official document in the research study. The data collected from the questionnaire, interviews and official documentation was analyzed and graphs were drawn and deductions were made from the results. Findings and recommendations were made from the data collected and a summary was compiled of the issues raised in the research study.
- Full Text:
- Date Issued: 2016
Assessment of the implementation of the National Certificate (Vocational) plant production modules
- Langa, Phakama Perry Macmillan
- Authors: Langa, Phakama Perry Macmillan
- Date: 2016
- Subjects: Technical education -- Curricula Vocational education -- Curricula Curriculum planning
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5391 , vital:29229
- Description: This study investigates the implementation of Language in Education Policy (LiEP) in learning and teaching in grades six from two schools. It critically examines the teachers’ practices and experiences towards English as the language of learning and teaching (LoLT) at two different primary schools from the eMalahleni in the Lady Frere Education District in the Eastern Cape. The study is guided by the fact that most learners use their mother tongue (isiXhosa) in classroom as well as outside classroom contexts. Furthermore, some teachers use the translation method of teaching language as they code-switch to their home language when teaching content subjects as well as English. Despite this practice in class, learners are expected to answer their test and examination questions in English. Theoretically, this study is underpinned by the constructivist view of language learning (Gaserfeld, 2003) and English as an international language (Sivasubramaniam, 2011). On the basis of the ecological and the constructivist approaches to language learning, Sivasubramaniam (2011 p.53) views language as a creative instrument of meaning which ‘has the power to create meaning anew and afresh’ each time that someone uses it. The study makes use of the qualitative research method with a case study design that is placed within the interpretive paradigm. The data collected will be analysed through the use of critical discourse analysis. The findings from the study suggest some instrumental motivations to use English as LOLT which is informed by Language policy. Some of these motivations are: studying abroad, business with foreign investors and integrative motivations as the learner will be able to communicate with people from different countries. The study concludes that there is need for schools to stick to the English medium because this acts as an open door to the upward economic mobility among the previously disadvantaged. Based on this, it can be recommended that schools stick to English first additional language as their language of teaching and learning.
- Full Text:
- Date Issued: 2016
- Authors: Langa, Phakama Perry Macmillan
- Date: 2016
- Subjects: Technical education -- Curricula Vocational education -- Curricula Curriculum planning
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5391 , vital:29229
- Description: This study investigates the implementation of Language in Education Policy (LiEP) in learning and teaching in grades six from two schools. It critically examines the teachers’ practices and experiences towards English as the language of learning and teaching (LoLT) at two different primary schools from the eMalahleni in the Lady Frere Education District in the Eastern Cape. The study is guided by the fact that most learners use their mother tongue (isiXhosa) in classroom as well as outside classroom contexts. Furthermore, some teachers use the translation method of teaching language as they code-switch to their home language when teaching content subjects as well as English. Despite this practice in class, learners are expected to answer their test and examination questions in English. Theoretically, this study is underpinned by the constructivist view of language learning (Gaserfeld, 2003) and English as an international language (Sivasubramaniam, 2011). On the basis of the ecological and the constructivist approaches to language learning, Sivasubramaniam (2011 p.53) views language as a creative instrument of meaning which ‘has the power to create meaning anew and afresh’ each time that someone uses it. The study makes use of the qualitative research method with a case study design that is placed within the interpretive paradigm. The data collected will be analysed through the use of critical discourse analysis. The findings from the study suggest some instrumental motivations to use English as LOLT which is informed by Language policy. Some of these motivations are: studying abroad, business with foreign investors and integrative motivations as the learner will be able to communicate with people from different countries. The study concludes that there is need for schools to stick to the English medium because this acts as an open door to the upward economic mobility among the previously disadvantaged. Based on this, it can be recommended that schools stick to English first additional language as their language of teaching and learning.
- Full Text:
- Date Issued: 2016
Assessment of the implementation of the National Certificate (Vocational) plant production modules
- Langa, Phakama Perry Macmillan
- Authors: Langa, Phakama Perry Macmillan
- Date: 2016
- Subjects: Curriculum planning Technical education -- Curricula Vocational education -- Curricula
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2359 , vital:27778
- Description: From 2010, the South African vocational skills education is offered by the Department of Higher Education and Training (DHET) through the Technical Vocational Education and Training (TVET) colleges. TVET colleges need to be transformed in order to empower young learners with the skills required by the various sectors of the economy. The purpose of this study was to assess the implementation of the National Certificate (Vocational) Plant Production module in Training and Vocational Education and Training (TVET) Colleges. The sample for this study is concurrent triangulation whereby complementary methods of data sources were brought together to offset each other‘s weaknesses. The sample for this study consisted of participants from three TVET colleges: one deep rural, one semi-rural/semi-urban and one urban in terms of geographical location. A total of 18 participants were interviewed: 2 subject advisors engaged by the colleges, 1 lecturer from college A, 3 lecturers from college B, 2 lecturers from college C, 4 graduates from college B, 3 graduates from college C and 3 employers .Research design for this study has features of both a survey and a case study. The mixed-method approach was applied using document analysis, questionnaires and interviews for data collection. The researcher found out that there is a disparity between the Plant Production guidelines and their implementation and assessment. Among the main reasons for failure to implement the guidelines properly are poor or inadequate infrastructure for doing practical work, high rate of student absenteeism within the investigated categories, and the high drop-out rate at Levels 2–4. To minimize the challenges in offering the Plant Production module, the study recommends that since some colleges cannot afford purchasing large sizes of land to properly implement the Plant Production guidelines, the government and the DHET should link the Primary Agriculture training to the land reform program where students can be trained under the land reform program.
- Full Text:
- Date Issued: 2016
- Authors: Langa, Phakama Perry Macmillan
- Date: 2016
- Subjects: Curriculum planning Technical education -- Curricula Vocational education -- Curricula
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2359 , vital:27778
- Description: From 2010, the South African vocational skills education is offered by the Department of Higher Education and Training (DHET) through the Technical Vocational Education and Training (TVET) colleges. TVET colleges need to be transformed in order to empower young learners with the skills required by the various sectors of the economy. The purpose of this study was to assess the implementation of the National Certificate (Vocational) Plant Production module in Training and Vocational Education and Training (TVET) Colleges. The sample for this study is concurrent triangulation whereby complementary methods of data sources were brought together to offset each other‘s weaknesses. The sample for this study consisted of participants from three TVET colleges: one deep rural, one semi-rural/semi-urban and one urban in terms of geographical location. A total of 18 participants were interviewed: 2 subject advisors engaged by the colleges, 1 lecturer from college A, 3 lecturers from college B, 2 lecturers from college C, 4 graduates from college B, 3 graduates from college C and 3 employers .Research design for this study has features of both a survey and a case study. The mixed-method approach was applied using document analysis, questionnaires and interviews for data collection. The researcher found out that there is a disparity between the Plant Production guidelines and their implementation and assessment. Among the main reasons for failure to implement the guidelines properly are poor or inadequate infrastructure for doing practical work, high rate of student absenteeism within the investigated categories, and the high drop-out rate at Levels 2–4. To minimize the challenges in offering the Plant Production module, the study recommends that since some colleges cannot afford purchasing large sizes of land to properly implement the Plant Production guidelines, the government and the DHET should link the Primary Agriculture training to the land reform program where students can be trained under the land reform program.
- Full Text:
- Date Issued: 2016
Being a black mine worker in South Africa: the case of Anglo Platinum Mine
- Authors: Maseko, Robert
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/651 , vital:19978
- Description: This thesis presents a decolonial perspective on the experience of being a black mineworker in post-apartheid South Africa with specific reference to the Platinum Belt. It seeks to understand what it means to be a black mineworker by unmasking and analysing the existence and prevalence of coloniality in contemporary South Africa despite the end of formal colonialism (i.e. apartheid). As a world-wide system, coloniality has different dimensions which all speak to and highlight continuities between the period of colonialism and the post-colonial period. These dimensions are coloniality of power, coloniality of being and coloniality of knowledge. The power structure of coloniality produces and reproduces the identity of the black mineworker in present-day South Africa as a sub-ontological being devoid of an authentic humanity such that the mineworker is depicted as incapable of rational thought and knowledge. The existential condition of the black mineworker is symptomatic of the generic experience of being a racialised subject of colour in the current global power structure predicated on the dominance and hegemony of Western-centred modernity. The black mineworker exists on the darker side of Western-centred modernity, living a life of wretchedness and continuing to suffer the colonial wound in the absence of formal colonialism and apartheid. The mineworker is disposable and dispensable and lives and works in the shadow of death. In pursuing this course of reasoning, I deploy the epistemic method of ‘shifting the geography of reason’ in order to read the experience of mineworkers in South Africa from the locus of enunciation of the oppressed subject within the scheme of a colonial power differential based on a hierarchy of humanity. This method allows me to speak with and from the perspective of the black mineworkers in the Platinum Belt as opposed to speaking for and about them. I reach the conclusion that being a platinum mineworker in post-apartheid South Africa is a racial and market determined identity of colonialised subjectivity that relegates the dominated subject (the black mineworker) to the realm of the subhuman. In setting the context for this claim, I trace the origins and development of the black mineworker in South Africa with reference to historical processes such as dispossession and proletarianisation. Empirically, the thesis is rooted in a contemporary case study of mainly Anglo Platinum Mine, which involved comprehensive fieldwork focusing on the present lived realities of platinum mineworkers. The dignity and humanity of these black mineworkers has still not returned despite twenty years of democratic rule in South Africa, such that race remains a crucial organising principle in postapartheid South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Maseko, Robert
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/651 , vital:19978
- Description: This thesis presents a decolonial perspective on the experience of being a black mineworker in post-apartheid South Africa with specific reference to the Platinum Belt. It seeks to understand what it means to be a black mineworker by unmasking and analysing the existence and prevalence of coloniality in contemporary South Africa despite the end of formal colonialism (i.e. apartheid). As a world-wide system, coloniality has different dimensions which all speak to and highlight continuities between the period of colonialism and the post-colonial period. These dimensions are coloniality of power, coloniality of being and coloniality of knowledge. The power structure of coloniality produces and reproduces the identity of the black mineworker in present-day South Africa as a sub-ontological being devoid of an authentic humanity such that the mineworker is depicted as incapable of rational thought and knowledge. The existential condition of the black mineworker is symptomatic of the generic experience of being a racialised subject of colour in the current global power structure predicated on the dominance and hegemony of Western-centred modernity. The black mineworker exists on the darker side of Western-centred modernity, living a life of wretchedness and continuing to suffer the colonial wound in the absence of formal colonialism and apartheid. The mineworker is disposable and dispensable and lives and works in the shadow of death. In pursuing this course of reasoning, I deploy the epistemic method of ‘shifting the geography of reason’ in order to read the experience of mineworkers in South Africa from the locus of enunciation of the oppressed subject within the scheme of a colonial power differential based on a hierarchy of humanity. This method allows me to speak with and from the perspective of the black mineworkers in the Platinum Belt as opposed to speaking for and about them. I reach the conclusion that being a platinum mineworker in post-apartheid South Africa is a racial and market determined identity of colonialised subjectivity that relegates the dominated subject (the black mineworker) to the realm of the subhuman. In setting the context for this claim, I trace the origins and development of the black mineworker in South Africa with reference to historical processes such as dispossession and proletarianisation. Empirically, the thesis is rooted in a contemporary case study of mainly Anglo Platinum Mine, which involved comprehensive fieldwork focusing on the present lived realities of platinum mineworkers. The dignity and humanity of these black mineworkers has still not returned despite twenty years of democratic rule in South Africa, such that race remains a crucial organising principle in postapartheid South Africa.
- Full Text:
- Date Issued: 2016
Benzoyl isothiocyanates derived ligands as potential HIV-1 protease inhibitors and their reactions with gold ions
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
Biocomposites from polyfurfuryl alcohol reinforced with microfibres and nanocellulose from flax fibres and maize stalks
- Mtibe, Asanda, Linganiso, Linda
- Authors: Mtibe, Asanda , Linganiso, Linda
- Date: 2016
- Subjects: Textile chemistry Textile chemicals Cellulose -- Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12175 , vital:27041
- Description: This study is aimed at extracting cellulose and nanocelluloses (cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs)) from maize stalks and flax fibres. Both flax fibres and maize stalks are composed of cellulose, lignin, hemicellulose and extractives. The extraction of cellulose involves the removal of lignin, hemicellulose and extractives. The presence of these components in plant fibres hinders the extraction of cellulose and nanocelluloses. Prior to extraction of cellulose, the different concentrations (1 wt.%, 1.5 wt.% and 2 wt.%) of NaOH were optimised. However, chemical compositions and XRD results revealed that the treatment of flax fibres with 1.5 wt.% sodium hydroxide (NaOH) gives optimum results and this concentration was further selected for the extraction of cellulose. Cellulose was extracted by chemical treatments (sodium hydroxide (NaOH), sodium chlorite (NaClO2) and potassium hydroxide (KOH)) and a combination of chemical treatments and mechanical process (supermass colloider). The materials obtained after each treatment stage during the extraction process were characterised by different characterisation techniques such as Fourier transform infrared (FTIR) spectroscopy, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results from the aforementioned characterisation techniques confirmed that cellulose was successfully extracted from flax fibres and maize stalks. Cellulose nanocrystals (CNCs) were extracted by sulphuric acid hydrolysis accompanied with ultra-sonication from cellulose obtained from flax fibres and maize stalks. The extracted CNCs were rod-like material with diameters and lengths in nanoscale and microscale, respectively. On the other hand, cellulose nanofibres (CNFs) were extracted by mechanical process (supermass colloider). The extracted CNFs were web-like material with diameters and lengths in nanoscale and microscale, respectively. The dimensions of nanocelluloses were measured by atomic force microscopy (AFM). Their dispersion was investigated by light polarised microscopy. The extracted nanocelluloses and cellulose were used to produce nanopapers and micropaper. Nanopapers mimic the traditional paper, the only difference of the nanopapers is that they are produced from high aspect ratio nanomaterials. Both nanopapers and micropapers were prepared by solvent evaporating method. Their thermal, optical and mechanical properties were investigated and compared. The mechanical and thermal properties of nanopapers produced from CNFs were better than those produced from CNCs and micropapers. On the other hand, nanopapers produced from CNCs were more transparent in comparison to nanopapers produced from CNFs and micropapers. Cellulosic fibres have attracted a considerable attention in composite materials due to their high tensile strength and tensile modulus. This study is focused on the development of biocomposites of polyfurfuryl alcohol (PFA) by in-situ polymerisation in the presence of acid catalyst (p-toluene sulphonic acid). Biocomposites were produced by reinforcing PFA with flax fibres (untreated and treated), nanoparticles and CNCs. The biocomposites reinforced with CNCs and flax fibres showed an improvement in mechanical, thermal and thermo-mechanical properties. On the other hand, biocomposites reinforced with nanoparticles obtained from treated maize stalks showed an improvement in mechanical and thermal properties while biocomposites reinforced with nanoparticles obtained from untreated maize stalks showed lower mechanical properties and decreased thermal stability.
- Full Text:
- Date Issued: 2016
- Authors: Mtibe, Asanda , Linganiso, Linda
- Date: 2016
- Subjects: Textile chemistry Textile chemicals Cellulose -- Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/12175 , vital:27041
- Description: This study is aimed at extracting cellulose and nanocelluloses (cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs)) from maize stalks and flax fibres. Both flax fibres and maize stalks are composed of cellulose, lignin, hemicellulose and extractives. The extraction of cellulose involves the removal of lignin, hemicellulose and extractives. The presence of these components in plant fibres hinders the extraction of cellulose and nanocelluloses. Prior to extraction of cellulose, the different concentrations (1 wt.%, 1.5 wt.% and 2 wt.%) of NaOH were optimised. However, chemical compositions and XRD results revealed that the treatment of flax fibres with 1.5 wt.% sodium hydroxide (NaOH) gives optimum results and this concentration was further selected for the extraction of cellulose. Cellulose was extracted by chemical treatments (sodium hydroxide (NaOH), sodium chlorite (NaClO2) and potassium hydroxide (KOH)) and a combination of chemical treatments and mechanical process (supermass colloider). The materials obtained after each treatment stage during the extraction process were characterised by different characterisation techniques such as Fourier transform infrared (FTIR) spectroscopy, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results from the aforementioned characterisation techniques confirmed that cellulose was successfully extracted from flax fibres and maize stalks. Cellulose nanocrystals (CNCs) were extracted by sulphuric acid hydrolysis accompanied with ultra-sonication from cellulose obtained from flax fibres and maize stalks. The extracted CNCs were rod-like material with diameters and lengths in nanoscale and microscale, respectively. On the other hand, cellulose nanofibres (CNFs) were extracted by mechanical process (supermass colloider). The extracted CNFs were web-like material with diameters and lengths in nanoscale and microscale, respectively. The dimensions of nanocelluloses were measured by atomic force microscopy (AFM). Their dispersion was investigated by light polarised microscopy. The extracted nanocelluloses and cellulose were used to produce nanopapers and micropaper. Nanopapers mimic the traditional paper, the only difference of the nanopapers is that they are produced from high aspect ratio nanomaterials. Both nanopapers and micropapers were prepared by solvent evaporating method. Their thermal, optical and mechanical properties were investigated and compared. The mechanical and thermal properties of nanopapers produced from CNFs were better than those produced from CNCs and micropapers. On the other hand, nanopapers produced from CNCs were more transparent in comparison to nanopapers produced from CNFs and micropapers. Cellulosic fibres have attracted a considerable attention in composite materials due to their high tensile strength and tensile modulus. This study is focused on the development of biocomposites of polyfurfuryl alcohol (PFA) by in-situ polymerisation in the presence of acid catalyst (p-toluene sulphonic acid). Biocomposites were produced by reinforcing PFA with flax fibres (untreated and treated), nanoparticles and CNCs. The biocomposites reinforced with CNCs and flax fibres showed an improvement in mechanical, thermal and thermo-mechanical properties. On the other hand, biocomposites reinforced with nanoparticles obtained from treated maize stalks showed an improvement in mechanical and thermal properties while biocomposites reinforced with nanoparticles obtained from untreated maize stalks showed lower mechanical properties and decreased thermal stability.
- Full Text:
- Date Issued: 2016