Elasticity of the South African economy towards portfolio investments in BRICS countries
- Authors: Taonezvi, Lovemore
- Date: 2019
- Subjects: Economic development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44537 , vital:38141
- Description: The emerging economies of Brazil, Russia, India, and China (BRIC) have been experiencing high growth rates since the turn of the millennium, whereas economic growth has been elusive in South Africa. As the newest member of BRICS, South Africa is expected to economically benefit through, amongst others, increases in capital flows, foreign investments by local firms, and increases in trade. Such benefits are anticipated to propel the country’s economic growth, thereby helping it to tackle its chronic problems of high unemployment, poverty, and economic inequality. The inclusion of South Africa in BRICS has, however, been viewed by critics as erroneous, since the country has, inter alia, poor economic growth; a small economy and population; and political instability. While foreign portfolio investment (FPI) inflows to South Africa have surged in recent years, economic growth has remained lacklustre. These flows have also faced sudden reversals, especially during the financial crisis of 2007-2009. With the potential to leverage its growth from intra-BRICS FPI inflows, it becomes of paramount significance for policymakers to have knowledge of the South African economy’s responsiveness to such inflows. With a theoretical framework based on the endogenous growth model, an augmented Cobb-Douglas production function was extended in this thesis in order to study the relationship between BRICS growth and intra-BRICS FPI in a dynamic panel data generalised method of moments (GMM) context. Similarly, the South African economy’s elasticity towards intraBRICS FPI was estimated. Vector autoregressive (VAR) analysis was used to evaluate the responsiveness of South Africa’s economy to an innovative shock to intra-BRICS FPI. Annual and quarterly data for the period 2000-2016 were used in panel data and VAR analysis, respectively. It was found that intra-BRICS FPI flows have a positive and statistically significant relationship with BRICS growth, while the elasticity of the South African economy to these flows is estimated at 0.007. Additionally, the efficiency and accessibility dimensions of financial market development do not assist FPI in promoting growth in BRICS, while financial market depth does. South Africa’s BRICS membership has a positive effect on its own growth, while for other BRICS nations, this membership is negative and insignificant. Credit rating downgrades have a negative and insignificant impact on economic growth, while the negative impact for inflation, government expenditure, and total labour employment is significant. Conversely, gross capital formation and trade openness have a positive and significant relationship with BRICS growth. The study also determined that a unit shock on intra-BRICS FPI resulted in negative fluctuations of South Africa’s economy within the first eight quarters before being positive and mostly constant thereafter. By supplementing domestic savings and facilitating the international integration of domestic financial markets, FPI promotes growth in BRICS. The short-term, ease of reversibility, and speculative nature of FPI are amongst some of the reasons for its destabilising effect on South Africa’s economy. Furthermore, inflation is a key determinant of FPI inflows to South Africa. Additional BRIC cooperation in FPI and trade; increased investments in domestic capital; reductions of inflation and corruption; investments in education and skills development; and stock market reforms are some of the recommendations for BRIC, and South Africa in particular. South Africa can consider prudential use of a mix of capital account controls, as well as fiscal and monetary policies to cushion its economy from FPI shocks in the short- to medium-term.
- Full Text:
- Date Issued: 2019
- Authors: Taonezvi, Lovemore
- Date: 2019
- Subjects: Economic development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44537 , vital:38141
- Description: The emerging economies of Brazil, Russia, India, and China (BRIC) have been experiencing high growth rates since the turn of the millennium, whereas economic growth has been elusive in South Africa. As the newest member of BRICS, South Africa is expected to economically benefit through, amongst others, increases in capital flows, foreign investments by local firms, and increases in trade. Such benefits are anticipated to propel the country’s economic growth, thereby helping it to tackle its chronic problems of high unemployment, poverty, and economic inequality. The inclusion of South Africa in BRICS has, however, been viewed by critics as erroneous, since the country has, inter alia, poor economic growth; a small economy and population; and political instability. While foreign portfolio investment (FPI) inflows to South Africa have surged in recent years, economic growth has remained lacklustre. These flows have also faced sudden reversals, especially during the financial crisis of 2007-2009. With the potential to leverage its growth from intra-BRICS FPI inflows, it becomes of paramount significance for policymakers to have knowledge of the South African economy’s responsiveness to such inflows. With a theoretical framework based on the endogenous growth model, an augmented Cobb-Douglas production function was extended in this thesis in order to study the relationship between BRICS growth and intra-BRICS FPI in a dynamic panel data generalised method of moments (GMM) context. Similarly, the South African economy’s elasticity towards intraBRICS FPI was estimated. Vector autoregressive (VAR) analysis was used to evaluate the responsiveness of South Africa’s economy to an innovative shock to intra-BRICS FPI. Annual and quarterly data for the period 2000-2016 were used in panel data and VAR analysis, respectively. It was found that intra-BRICS FPI flows have a positive and statistically significant relationship with BRICS growth, while the elasticity of the South African economy to these flows is estimated at 0.007. Additionally, the efficiency and accessibility dimensions of financial market development do not assist FPI in promoting growth in BRICS, while financial market depth does. South Africa’s BRICS membership has a positive effect on its own growth, while for other BRICS nations, this membership is negative and insignificant. Credit rating downgrades have a negative and insignificant impact on economic growth, while the negative impact for inflation, government expenditure, and total labour employment is significant. Conversely, gross capital formation and trade openness have a positive and significant relationship with BRICS growth. The study also determined that a unit shock on intra-BRICS FPI resulted in negative fluctuations of South Africa’s economy within the first eight quarters before being positive and mostly constant thereafter. By supplementing domestic savings and facilitating the international integration of domestic financial markets, FPI promotes growth in BRICS. The short-term, ease of reversibility, and speculative nature of FPI are amongst some of the reasons for its destabilising effect on South Africa’s economy. Furthermore, inflation is a key determinant of FPI inflows to South Africa. Additional BRIC cooperation in FPI and trade; increased investments in domestic capital; reductions of inflation and corruption; investments in education and skills development; and stock market reforms are some of the recommendations for BRIC, and South Africa in particular. South Africa can consider prudential use of a mix of capital account controls, as well as fiscal and monetary policies to cushion its economy from FPI shocks in the short- to medium-term.
- Full Text:
- Date Issued: 2019
Electrical, photo-thermal and mechanical degradation analysis of degraded single junction amorphous silicon solar modules
- Osayemwenre, Gilbert Omorodion
- Authors: Osayemwenre, Gilbert Omorodion
- Date: 2019
- Subjects: Solar cells Amorphous semiconductors Silicon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15211 , vital:40204
- Description: In this present era of sustainable energy development, photovoltaic modules which are based on amorphous silicon cells have immeasurable prospects of contributing meaningfully to the energy demand of the world at large. The global consciousness of environmental safety issues has birthed the rapid demand for the photovoltaic system. However, the production increase is mainly in bulk-type crystalline (c-Si) solar cells. Thus, to meet the high demand of the market, single junction amorphous silicon (a-Si:H) solar cells production must be encouraged through active research in that regard. This could also help to improve its efficiency and reliability. There has recently been a sharp decrease in the production cost of the bulk Si solar cell, but the a-Si:H solar cell still remains the most economically viable in comparison to the other PV technologies. Companies such as Sharp are currently developing large-scale a-Si:H solar modules that can produce an efficiency of 10.5% after the long-term degradation process. To date, a-Si:H is believed to be one of the most promising thin-film PV technologies (Saito et al., 1993; Hamakawa et al., 1994). The cost of a solar PV manufacturing fell by 6% in 2014 (Santa, 2014), this is in accordance with the 2008 cost production forecast; thus, the cost record stands at 0.20 per watt, as reported by the NPD Solar publisher. Amorphous silicon (a-Si) solar modules generate more kilowatt-hour (kWh) of electricity per kilowatt (kW) than crystalline silicon or other technologies of the same capacity of installation. Furthermore, a-Si:H modules have more functional hours per day. Single junction amorphous silicon (a-Si:H) modules can function beyond the peak sun hours, and they also have a better performance on a cloudy day. vii In other words, a 1kW PV system of a-Si:H is expected to generate more electricity per year in comparison to 1kW PV from other technologies, hence there is a low energy payback time. In this study, commercially available single junction amorphous silicon modules were bought from a local market and they were immediately deployed outdoors. The initial reading of the modules, which served as baseline reading, showed an average of 25% decrease in the modules performance, therefore, there is a need for a long term monitoring process to obtain the best and worst performing modules. Measuring the performance parameters of these PV modules under real sun light (IV) provides a better degradation assessment. This conventional assessment cannot provide an in-depth insight responsible for the variation and degradation of the performance parameters. More obscured parameters like recombination current and ideality factor were obtained from the dark IV measurements. However, this is still superficial in a way. The intrinsic parameters were obtained from scanning probe microscopy (SPM) and CV measurements. The study focuses on the degradation analysis of a-Si:H due to an increase in defect density. A rise in the defect concentration is a huge problem because it causes long-term solar cell degradation, which increases the recombination current and decreases the conversion efficiency. Furthermore, it decreases the photo-generating current and reduces the effective efficiency of the solar device. In other words, the electrical output decreases. This research investigates the reduction in a-Si:H modules’ maximum power, and correlates these with a hot spot formation. A PVPM IV tracer was used for the outdoor characterisation of the module’s temperature profile, while the IR camera was used to analyse the hot spot centre. A four probe IV/CV from NMU was used for the indoor assessment of smaller samples cleaved from both the affected and non-affected regions to characterise the electrical variations across the module viii samples. To be precise, in this study, a naturally degraded single junction amorphous silicon module was delaminated and its mechanical properties were analysed and correlated with the contact potential from a Kelvin probe force microscopy (KPFM).
- Full Text:
- Date Issued: 2019
- Authors: Osayemwenre, Gilbert Omorodion
- Date: 2019
- Subjects: Solar cells Amorphous semiconductors Silicon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15211 , vital:40204
- Description: In this present era of sustainable energy development, photovoltaic modules which are based on amorphous silicon cells have immeasurable prospects of contributing meaningfully to the energy demand of the world at large. The global consciousness of environmental safety issues has birthed the rapid demand for the photovoltaic system. However, the production increase is mainly in bulk-type crystalline (c-Si) solar cells. Thus, to meet the high demand of the market, single junction amorphous silicon (a-Si:H) solar cells production must be encouraged through active research in that regard. This could also help to improve its efficiency and reliability. There has recently been a sharp decrease in the production cost of the bulk Si solar cell, but the a-Si:H solar cell still remains the most economically viable in comparison to the other PV technologies. Companies such as Sharp are currently developing large-scale a-Si:H solar modules that can produce an efficiency of 10.5% after the long-term degradation process. To date, a-Si:H is believed to be one of the most promising thin-film PV technologies (Saito et al., 1993; Hamakawa et al., 1994). The cost of a solar PV manufacturing fell by 6% in 2014 (Santa, 2014), this is in accordance with the 2008 cost production forecast; thus, the cost record stands at 0.20 per watt, as reported by the NPD Solar publisher. Amorphous silicon (a-Si) solar modules generate more kilowatt-hour (kWh) of electricity per kilowatt (kW) than crystalline silicon or other technologies of the same capacity of installation. Furthermore, a-Si:H modules have more functional hours per day. Single junction amorphous silicon (a-Si:H) modules can function beyond the peak sun hours, and they also have a better performance on a cloudy day. vii In other words, a 1kW PV system of a-Si:H is expected to generate more electricity per year in comparison to 1kW PV from other technologies, hence there is a low energy payback time. In this study, commercially available single junction amorphous silicon modules were bought from a local market and they were immediately deployed outdoors. The initial reading of the modules, which served as baseline reading, showed an average of 25% decrease in the modules performance, therefore, there is a need for a long term monitoring process to obtain the best and worst performing modules. Measuring the performance parameters of these PV modules under real sun light (IV) provides a better degradation assessment. This conventional assessment cannot provide an in-depth insight responsible for the variation and degradation of the performance parameters. More obscured parameters like recombination current and ideality factor were obtained from the dark IV measurements. However, this is still superficial in a way. The intrinsic parameters were obtained from scanning probe microscopy (SPM) and CV measurements. The study focuses on the degradation analysis of a-Si:H due to an increase in defect density. A rise in the defect concentration is a huge problem because it causes long-term solar cell degradation, which increases the recombination current and decreases the conversion efficiency. Furthermore, it decreases the photo-generating current and reduces the effective efficiency of the solar device. In other words, the electrical output decreases. This research investigates the reduction in a-Si:H modules’ maximum power, and correlates these with a hot spot formation. A PVPM IV tracer was used for the outdoor characterisation of the module’s temperature profile, while the IR camera was used to analyse the hot spot centre. A four probe IV/CV from NMU was used for the indoor assessment of smaller samples cleaved from both the affected and non-affected regions to characterise the electrical variations across the module viii samples. To be precise, in this study, a naturally degraded single junction amorphous silicon module was delaminated and its mechanical properties were analysed and correlated with the contact potential from a Kelvin probe force microscopy (KPFM).
- Full Text:
- Date Issued: 2019
Elucidating the Molecular Basis of the Interaction between the β2-integrin, αXβ2, and the low-affinity IgE Receptor, CD23
- Authors: Clarke, Stephen
- Date: 2019
- Subjects: CD23 antigen , Immune response Cellular immunity Molecular immunology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/37990 , vital:34277
- Description: The low affinity IgE receptor, CD23, is involved in a myriad of immune reactions. It is not only a receptor for IgE, but also functions in the regulation of IgE synthesis, isotype switching in B cells, and induction of the inflammatory response. These effector functions of CD23 arise through its interaction with another leukocyte-specific cell surface receptor – the β2 integrin subfamily. However, this interaction has not been fully described. It has been shown that CD23 is capable of interacting with the β3 and β5 integrin β-subunit of integrins via a basic RKC motif in a metal cation-independent fashion. The currently proposed mechanism for the interaction between CD23 and the integrin superfamily was applied to the β2 integrin subfamily. In this study the interaction was probed for whether or not the RKC motif governs the interaction as well. This was done by performing bioinformatics docking predictions between the CD23 and αXβ2 integrin proteins. This revealed that in the absence of cations, the RKC motif is involved in interaction with the integrin αI domain. However, since physiologically integrin activity has been shown to be regulated by metal cations, docking predictions were also performed in the presence of such cations. This showed the interaction to involve novel acidic motifs within the CD23 protein, GEF and LDL. This same pattern of interaction was seen in docking predictions between CD23 and the β2- and β3I-like domains. To further investigate, recombinant proteins of sCD23 and the αXI domain were produced using E. coli expression systems. The DNA sequence was mutated to produce mutant versions of the CD23 RKC and GEF motifs as well as a high-affinity locked αXI domain. These proteins were used in subsequent SPR spectroscopy analysis of the binding affinity between immobilised integrin and CD23 analyte. It was shown that the mutation within the RKC motif reduced the binding affinity under cation-independence, especially when the Arg172 residue was substituted. However binding was not completely lost. This result was supported by synthetic peptides containing the same RKC motif and substitutions. These showed complete loss in binding in the double RKΔAA substitution, suggesting the involvement of other residues in the RKC-dependent interaction. In contrast, under cation dependence, the RKC motif substitutions showed no effect on binding affinity, while the GEF motif substitution exhibited near complete loss in binding. This same effect on binding was validated by U937 cell-based ELISA using live cells. This showed decreased capture of differentiated U937 cells, expressing the αXβ2 integrin, by immobilised recombinant sCD23 protein. In this study it was noted that, 2 contrary to the SPR analysis, metal cations allowed for a higher titre of cells to be captured in comparison to the cation-free binding.
- Full Text:
- Date Issued: 2019
- Authors: Clarke, Stephen
- Date: 2019
- Subjects: CD23 antigen , Immune response Cellular immunity Molecular immunology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/37990 , vital:34277
- Description: The low affinity IgE receptor, CD23, is involved in a myriad of immune reactions. It is not only a receptor for IgE, but also functions in the regulation of IgE synthesis, isotype switching in B cells, and induction of the inflammatory response. These effector functions of CD23 arise through its interaction with another leukocyte-specific cell surface receptor – the β2 integrin subfamily. However, this interaction has not been fully described. It has been shown that CD23 is capable of interacting with the β3 and β5 integrin β-subunit of integrins via a basic RKC motif in a metal cation-independent fashion. The currently proposed mechanism for the interaction between CD23 and the integrin superfamily was applied to the β2 integrin subfamily. In this study the interaction was probed for whether or not the RKC motif governs the interaction as well. This was done by performing bioinformatics docking predictions between the CD23 and αXβ2 integrin proteins. This revealed that in the absence of cations, the RKC motif is involved in interaction with the integrin αI domain. However, since physiologically integrin activity has been shown to be regulated by metal cations, docking predictions were also performed in the presence of such cations. This showed the interaction to involve novel acidic motifs within the CD23 protein, GEF and LDL. This same pattern of interaction was seen in docking predictions between CD23 and the β2- and β3I-like domains. To further investigate, recombinant proteins of sCD23 and the αXI domain were produced using E. coli expression systems. The DNA sequence was mutated to produce mutant versions of the CD23 RKC and GEF motifs as well as a high-affinity locked αXI domain. These proteins were used in subsequent SPR spectroscopy analysis of the binding affinity between immobilised integrin and CD23 analyte. It was shown that the mutation within the RKC motif reduced the binding affinity under cation-independence, especially when the Arg172 residue was substituted. However binding was not completely lost. This result was supported by synthetic peptides containing the same RKC motif and substitutions. These showed complete loss in binding in the double RKΔAA substitution, suggesting the involvement of other residues in the RKC-dependent interaction. In contrast, under cation dependence, the RKC motif substitutions showed no effect on binding affinity, while the GEF motif substitution exhibited near complete loss in binding. This same effect on binding was validated by U937 cell-based ELISA using live cells. This showed decreased capture of differentiated U937 cells, expressing the αXβ2 integrin, by immobilised recombinant sCD23 protein. In this study it was noted that, 2 contrary to the SPR analysis, metal cations allowed for a higher titre of cells to be captured in comparison to the cation-free binding.
- Full Text:
- Date Issued: 2019
Employee talent management in the Uganda health sector: a public institutions perspective
- Authors: Nakato, Jamidah
- Date: 2019
- Subjects: Employee retention -- Uganda , Leadership -- Uganda Executives -- Training of Executive ability
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/41751 , vital:36578
- Description: Globally, talent management has been acknowledged as a prime source of employee attraction and retention as well as organisational performance and commitment. Although the health sector plays an important role in the economic development of any country, in Uganda, the management of talented employees still remains a challenge. In this country, many institutions have not incorporated and adopted suitable talent management strategies, thus compromising access to and quality of care. A hypothetical model and measuring instruments were developed to investigate the factors contributing to and the benefits of effective employee talent management in the Ugandan health sector. The following ten independent variables that have the prospect of influencing effective talent management (intervening variable) were identified on the basis of organisational, management and personal factors: talent pool, organisational support, work conditions, social and work environment, reward system, leadership styles, career development, supervisor support, employee engagement and employee personality. In this study, it was also postulated that talent management has potential to effect the dependent variables, namely, talent attraction, employee retention, organisational performance and organisational commitment. In total, fourteen hypotheses were formulated to test relationships between independent, intervening and dependent variables. The study utilised the quantitative research paradigm in order to seek employee perceptions regarding public institutions within the health sector, in Uganda’s Central region. Using stratified random sampling, a sample of 910 participants was drawn from the identified population. A survey was conducted with the aid of a structured, selfadministered questionnaire that was distributed to the seven categories of hospitals and health centres in Central Uganda; 910 questionnaires were distributed to doctors, consultants, dentists, dispensers, nurses, pharmacists, clinical officers, laboratory staff, occupational therapists, allied health staff, environmental health officers, general administrative cadres, cold chain technicians and support staff. Of these, 655 were useable, which indicates a 71% response rate. The data collected was captured and analysed using various statistical analysis techniques. The study findings reveal that organisational support, employee satisfaction, an enabling work environment, a stable working environment and career development effectively influence talent management. However, management in health sector institutions need to realise the importance of facilitating and monitoring job autonomy and personal values in order to effectively enhance talent management. The study results further reveal that talent management has a positive influence on employee retention and holistic development for organisational performance. For optimal talent management, the study recommends that organisations pay attention to cultivating an enabling and stable work environment that is suitable for motivating employees towards improved performance and work commitment. Therefore, health sector management should focus on potential, and not only on performance, by matching individuals with the right positions that can expose their capabilities and potential. It was further recommended that organisations need to accept and show confidence in their employees by allowing them freedom in carrying out their tasks. In addition, it was highlighted that ascertaining and utilising information about the values and principles that employees hold can help explain their behaviours and attitudes at work. This would increase the chances of talented employees realising their full potential and competencies in their jobs. Therefore, this study found that there is a need for public institutions within the health sector to focus on supporting employees by offering a well-defined career development programme, which caters for the needs of individuals and which acts as an incentive for the recruitment of qualified employees. Thus, management will succeed in retaining, attracting and maintaining talented individuals who can perform well. In order to uphold the expected ethical behaviour of conducting research, the researcher obtained approval and ethics clearance from Nelson Mandela University, permission to conduct the study from the Ugandan Ministry of Health, and communicated all the information relevant to the study to the participants.
- Full Text:
- Date Issued: 2019
- Authors: Nakato, Jamidah
- Date: 2019
- Subjects: Employee retention -- Uganda , Leadership -- Uganda Executives -- Training of Executive ability
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/41751 , vital:36578
- Description: Globally, talent management has been acknowledged as a prime source of employee attraction and retention as well as organisational performance and commitment. Although the health sector plays an important role in the economic development of any country, in Uganda, the management of talented employees still remains a challenge. In this country, many institutions have not incorporated and adopted suitable talent management strategies, thus compromising access to and quality of care. A hypothetical model and measuring instruments were developed to investigate the factors contributing to and the benefits of effective employee talent management in the Ugandan health sector. The following ten independent variables that have the prospect of influencing effective talent management (intervening variable) were identified on the basis of organisational, management and personal factors: talent pool, organisational support, work conditions, social and work environment, reward system, leadership styles, career development, supervisor support, employee engagement and employee personality. In this study, it was also postulated that talent management has potential to effect the dependent variables, namely, talent attraction, employee retention, organisational performance and organisational commitment. In total, fourteen hypotheses were formulated to test relationships between independent, intervening and dependent variables. The study utilised the quantitative research paradigm in order to seek employee perceptions regarding public institutions within the health sector, in Uganda’s Central region. Using stratified random sampling, a sample of 910 participants was drawn from the identified population. A survey was conducted with the aid of a structured, selfadministered questionnaire that was distributed to the seven categories of hospitals and health centres in Central Uganda; 910 questionnaires were distributed to doctors, consultants, dentists, dispensers, nurses, pharmacists, clinical officers, laboratory staff, occupational therapists, allied health staff, environmental health officers, general administrative cadres, cold chain technicians and support staff. Of these, 655 were useable, which indicates a 71% response rate. The data collected was captured and analysed using various statistical analysis techniques. The study findings reveal that organisational support, employee satisfaction, an enabling work environment, a stable working environment and career development effectively influence talent management. However, management in health sector institutions need to realise the importance of facilitating and monitoring job autonomy and personal values in order to effectively enhance talent management. The study results further reveal that talent management has a positive influence on employee retention and holistic development for organisational performance. For optimal talent management, the study recommends that organisations pay attention to cultivating an enabling and stable work environment that is suitable for motivating employees towards improved performance and work commitment. Therefore, health sector management should focus on potential, and not only on performance, by matching individuals with the right positions that can expose their capabilities and potential. It was further recommended that organisations need to accept and show confidence in their employees by allowing them freedom in carrying out their tasks. In addition, it was highlighted that ascertaining and utilising information about the values and principles that employees hold can help explain their behaviours and attitudes at work. This would increase the chances of talented employees realising their full potential and competencies in their jobs. Therefore, this study found that there is a need for public institutions within the health sector to focus on supporting employees by offering a well-defined career development programme, which caters for the needs of individuals and which acts as an incentive for the recruitment of qualified employees. Thus, management will succeed in retaining, attracting and maintaining talented individuals who can perform well. In order to uphold the expected ethical behaviour of conducting research, the researcher obtained approval and ethics clearance from Nelson Mandela University, permission to conduct the study from the Ugandan Ministry of Health, and communicated all the information relevant to the study to the participants.
- Full Text:
- Date Issued: 2019
Energy yield modelling and analysis of photovoltaic systems in Namibia
- Authors: Dobreva, Petja
- Date: 2019
- Subjects: Photovoltaic power systems , Photovoltaic power generation Photovoltaic power generation -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/39523 , vital:35287
- Description: Generation of electricity from solar energy by photovoltaic systems has the potential to reduce dependence on non-renewable sources for electrical energy production. It can also reduce the cost of electricity for consumers by moving away from the traditional models of centralised generation combined with extensive transmission. The prices of photovoltaic system components have decreased so dramatically in recent years that nowadays a large portion of the cost of electricity produced by photovoltaic systems is due to the cost of investment capital rather than the cost of the physical parts of the system. The cost of capital is determined by the perceived risk of the investment and is contingent on predictive models whose aim is to project outputs reasonably achievable by the system. The output of a photovoltaic system depends strongly on external factors, like solar radiation and temperature, as well as internal, system specific factors. Models that can accurately predict the output of a photovoltaic system have direct impact on investment cost. Several measures, like root-mean-square-error or coincident of determination, have been used in the past to assess accuracy of models but they appear to be inadequate for the task. I suggest a new method, comprising qualitative and quantitative measures, for model evaluation and introduce two new quantities to assess the predictive capabilities of the models. Models of several photovoltaic systems in Namibia were created, the new evaluation approach was applied to them and the results were compared to the conclusions that would have been drawn if the old measures were used. Outdoor current-voltage measurements are used to assess the power output and general state of the solar generator of a photovoltaic system, but the measured values strongly depend on irradiance and temperature. The prevailing approach has been to transform the current-voltage characteristics to standard-test-conditions with the so-called translation equations and then compare the translated power to the nominal value. The translated value of the power, however, depends on the translation equations used and is not necessarily an accurate reaction of the state of the solar generator. I have proposed a new method for assessment of the state of the solar generator that relies only on the measured quantities and does not require translations to standard-test-conditions. This alternative method has been used in the assessment of the condition of the solar generators in the systems included in this study.
- Full Text:
- Date Issued: 2019
- Authors: Dobreva, Petja
- Date: 2019
- Subjects: Photovoltaic power systems , Photovoltaic power generation Photovoltaic power generation -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/39523 , vital:35287
- Description: Generation of electricity from solar energy by photovoltaic systems has the potential to reduce dependence on non-renewable sources for electrical energy production. It can also reduce the cost of electricity for consumers by moving away from the traditional models of centralised generation combined with extensive transmission. The prices of photovoltaic system components have decreased so dramatically in recent years that nowadays a large portion of the cost of electricity produced by photovoltaic systems is due to the cost of investment capital rather than the cost of the physical parts of the system. The cost of capital is determined by the perceived risk of the investment and is contingent on predictive models whose aim is to project outputs reasonably achievable by the system. The output of a photovoltaic system depends strongly on external factors, like solar radiation and temperature, as well as internal, system specific factors. Models that can accurately predict the output of a photovoltaic system have direct impact on investment cost. Several measures, like root-mean-square-error or coincident of determination, have been used in the past to assess accuracy of models but they appear to be inadequate for the task. I suggest a new method, comprising qualitative and quantitative measures, for model evaluation and introduce two new quantities to assess the predictive capabilities of the models. Models of several photovoltaic systems in Namibia were created, the new evaluation approach was applied to them and the results were compared to the conclusions that would have been drawn if the old measures were used. Outdoor current-voltage measurements are used to assess the power output and general state of the solar generator of a photovoltaic system, but the measured values strongly depend on irradiance and temperature. The prevailing approach has been to transform the current-voltage characteristics to standard-test-conditions with the so-called translation equations and then compare the translated power to the nominal value. The translated value of the power, however, depends on the translation equations used and is not necessarily an accurate reaction of the state of the solar generator. I have proposed a new method for assessment of the state of the solar generator that relies only on the measured quantities and does not require translations to standard-test-conditions. This alternative method has been used in the assessment of the condition of the solar generators in the systems included in this study.
- Full Text:
- Date Issued: 2019
Enumeration, conformation sampling and population of libraries of peptide macrocycles for the search of chemotherapeutic cardioprotection agents
- Authors: Sigauke, Lester Takunda
- Date: 2019
- Subjects: Peptides -- Synthesis , Macrocyclic compounds , Drug development , Drug discovery , Cardiovascular system -- Diseases -- Prevention , Proteins -- Synthesis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116056 , vital:34293
- Description: Peptides are uniquely endowed with features that allow them to perturb previously difficult to drug biomolecular targets. Peptide macrocycles in particular have seen a flurry of recent interest due to their enhanced bioavailability, tunability and specificity. Although these properties make them attractive hit-candidates in early stage drug discovery, knowing which peptides to pursue is non‐trivial due to the magnitude of the peptide sequence space. Computational screening approaches show promise in their ability to address the size of this search space but suffer from their inability to accurately interrogate the conformational landscape of peptide macrocycles. We developed an in‐silico compound enumerator that was tasked with populating a conformationally laden peptide virtual library. This library was then used in the search for cardio‐protective agents (that may be administered, reducing tissue damage during reperfusion after ischemia (heart attacks)). Our enumerator successfully generated a library of 15.2 billion compounds, requiring the use of compression algorithms, conformational sampling protocols and management of aggregated compute resources in the context of a local cluster. In the absence of experimental biophysical data, we performed biased sampling during alchemical molecular dynamics simulations in order to observe cyclophilin‐D perturbation by cyclosporine A and its mitochondrial targeted analogue. Reliable intermediate state averaging through a WHAM analysis of the biased dynamic pulling simulations confirmed that the cardio‐protective activity of cyclosporine A was due to its mitochondrial targeting. Paralleltempered solution molecular dynamics in combination with efficient clustering isolated the essential dynamics of a cyclic peptide scaffold. The rapid enumeration of skeletons from these essential dynamics gave rise to a conformation laden virtual library of all the 15.2 Billion unique cyclic peptides (given the limits on peptide sequence imposed). Analysis of this library showed the exact extent of physicochemical properties covered, relative to the bare scaffold precursor. Molecular docking of a subset of the virtual library against cyclophilin‐D showed significant improvements in affinity to the target (relative to cyclosporine A). The conformation laden virtual library, accessed by our methodology, provided derivatives that were able to make many interactions per peptide with the cyclophilin‐D target. Machine learning methods showed promise in the training of Support Vector Machines for synthetic feasibility prediction for this library. The synergy between enumeration and conformational sampling greatly improves the performance of this library during virtual screening, even when only a subset is used.
- Full Text:
- Date Issued: 2019
- Authors: Sigauke, Lester Takunda
- Date: 2019
- Subjects: Peptides -- Synthesis , Macrocyclic compounds , Drug development , Drug discovery , Cardiovascular system -- Diseases -- Prevention , Proteins -- Synthesis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116056 , vital:34293
- Description: Peptides are uniquely endowed with features that allow them to perturb previously difficult to drug biomolecular targets. Peptide macrocycles in particular have seen a flurry of recent interest due to their enhanced bioavailability, tunability and specificity. Although these properties make them attractive hit-candidates in early stage drug discovery, knowing which peptides to pursue is non‐trivial due to the magnitude of the peptide sequence space. Computational screening approaches show promise in their ability to address the size of this search space but suffer from their inability to accurately interrogate the conformational landscape of peptide macrocycles. We developed an in‐silico compound enumerator that was tasked with populating a conformationally laden peptide virtual library. This library was then used in the search for cardio‐protective agents (that may be administered, reducing tissue damage during reperfusion after ischemia (heart attacks)). Our enumerator successfully generated a library of 15.2 billion compounds, requiring the use of compression algorithms, conformational sampling protocols and management of aggregated compute resources in the context of a local cluster. In the absence of experimental biophysical data, we performed biased sampling during alchemical molecular dynamics simulations in order to observe cyclophilin‐D perturbation by cyclosporine A and its mitochondrial targeted analogue. Reliable intermediate state averaging through a WHAM analysis of the biased dynamic pulling simulations confirmed that the cardio‐protective activity of cyclosporine A was due to its mitochondrial targeting. Paralleltempered solution molecular dynamics in combination with efficient clustering isolated the essential dynamics of a cyclic peptide scaffold. The rapid enumeration of skeletons from these essential dynamics gave rise to a conformation laden virtual library of all the 15.2 Billion unique cyclic peptides (given the limits on peptide sequence imposed). Analysis of this library showed the exact extent of physicochemical properties covered, relative to the bare scaffold precursor. Molecular docking of a subset of the virtual library against cyclophilin‐D showed significant improvements in affinity to the target (relative to cyclosporine A). The conformation laden virtual library, accessed by our methodology, provided derivatives that were able to make many interactions per peptide with the cyclophilin‐D target. Machine learning methods showed promise in the training of Support Vector Machines for synthetic feasibility prediction for this library. The synergy between enumeration and conformational sampling greatly improves the performance of this library during virtual screening, even when only a subset is used.
- Full Text:
- Date Issued: 2019
Evaluating Livestock Development Programmes through the Production Risk Interface: Case of the Kaonafatso ya Dikgomo (KyD) Scheme in South Africa
- Authors: Ngarava, Saul
- Date: 2019
- Subjects: Livestock projects
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/15730 , vital:40513
- Description: Livestock is significant in the livelihoods of the rural poor, providing a plethora of benefits. Livestock Development Programmes (LDPs) can transform smallholder farmers’ production for increased production and poverty reduction. The Kaonafatso ya Dikgomo (KyD) Scheme is a LDP implemented in South Africa with the aim of assisting smallholder farmers to attain economic and sustainable beef production. The literature shows that most evaluations of LDPs have been quantitative based on measurable and quantifiable metrics. Furthermore, various socio-economic and institutional factors have a bearing on the decision to participate in LDPs and eventually adopting the practices. Impact assessments of LDPs have been devoid of risk consideration as well as ascertaining how risk introduced by participating in LDPs has impacted productivity. The overall objective of the study was therefore to evaluate LDPs, focussing on benefits, participation and risk. The specific objectives of the study entailed developing a conceptual tool for measuring the qualitative and secondary benefits. Secondly, it was to determine factors influencing participation decisions in the KyD Scheme. Thirdly, the study sought to measure and compare calving rate and off-take rate risk between KyD Scheme participants and non-participants. Lastly, the study highlighted the variability (risk) introduced by participating in a LDP and its impact on production. The study utilised a cross-sectional survey of KyD Scheme participants and nonparticipants in KwaZulu-Natal, Limpopo and Eastern Cape Provinces of South Africa. Non-probability convenience sampling method was utilised in selecting a sample of 164 KyD Scheme participants and 81 non-participants. A semi-structured questionnaire was the data collection tool utilised. A conceptual “Livelihood Effect Benefit Index”; Probit, Tobit and Ordered Probit models; Just and Pope Production function; Propensity Score Matching; and Monte Carlo Simulations were utilised to analyse data. Statistical Package for Social Scientists version 24, STATA 13 and @Risk Decision Tool were the analytical packages utilised in analysing the data. The study found that the Scheme provided low qualitative benefits, mainly through social capital. Furthermore, socio-economic and institutional factors have significant impact on the decision to participate in the Scheme, extent of participation and decision to continue practicing Scheme experiences. In comparing the two groups of Scheme and Scheme non-participants, calving and off-take risk for KyD Scheme participants was lower than that of Scheme non-participants. In comparing individuals with similar characteristics between the two groups, Scheme participants reduced calving risk whilst increasing the off-take risk. Page | vi The study concluded that the Scheme exhibited low qualitative benefits. Furthermore, the decisions to participate and the extent of participation in the KyD Scheme were influenced by various socio-economic and institutional factors, which were however more favourable to resource endowed smallholder farmers. In addition, the Scheme had significant impact on production risk. The risk reducing determinants appeared to also favour more resource endowed smallholder farmers who had more farming experience. The study’s recommendations were subdivided into short term, medium term and long term. The short term recommendations included targeting farmers within a distance of between 30km and 90km from a formal market, promoting dipping services-based training and extension, and providing information and training concerning calving i.e. animal health, husbandry and breed selection for herd maximization. Participation in the Scheme and the extent of participation can be improved through enhancing awareness of the Scheme at various points where stock feed are available to farmers. Furthermore, enhanced cooperation with extension workers provides a conduit in improving awareness of the Scheme and enhancing participation. The medium term recommendations pertained to initiatives such as promoting other livelihood options to enhance benefits of the programme, and promoting social capital enhancing initiatives such as mentoring and providing social capital objectives that can be integrated into the overall livestock sector strategy. The long-term recommendations include initiatives such as subsidizing increase in herd size to between 50 and 120 cattle, maintaining a monthly frequency of farmer-extension contact of between 2 and 5 times per month, as well as incorporating calving and off-take risk in policy formulation, implementation and evaluation
- Full Text:
- Date Issued: 2019
- Authors: Ngarava, Saul
- Date: 2019
- Subjects: Livestock projects
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/15730 , vital:40513
- Description: Livestock is significant in the livelihoods of the rural poor, providing a plethora of benefits. Livestock Development Programmes (LDPs) can transform smallholder farmers’ production for increased production and poverty reduction. The Kaonafatso ya Dikgomo (KyD) Scheme is a LDP implemented in South Africa with the aim of assisting smallholder farmers to attain economic and sustainable beef production. The literature shows that most evaluations of LDPs have been quantitative based on measurable and quantifiable metrics. Furthermore, various socio-economic and institutional factors have a bearing on the decision to participate in LDPs and eventually adopting the practices. Impact assessments of LDPs have been devoid of risk consideration as well as ascertaining how risk introduced by participating in LDPs has impacted productivity. The overall objective of the study was therefore to evaluate LDPs, focussing on benefits, participation and risk. The specific objectives of the study entailed developing a conceptual tool for measuring the qualitative and secondary benefits. Secondly, it was to determine factors influencing participation decisions in the KyD Scheme. Thirdly, the study sought to measure and compare calving rate and off-take rate risk between KyD Scheme participants and non-participants. Lastly, the study highlighted the variability (risk) introduced by participating in a LDP and its impact on production. The study utilised a cross-sectional survey of KyD Scheme participants and nonparticipants in KwaZulu-Natal, Limpopo and Eastern Cape Provinces of South Africa. Non-probability convenience sampling method was utilised in selecting a sample of 164 KyD Scheme participants and 81 non-participants. A semi-structured questionnaire was the data collection tool utilised. A conceptual “Livelihood Effect Benefit Index”; Probit, Tobit and Ordered Probit models; Just and Pope Production function; Propensity Score Matching; and Monte Carlo Simulations were utilised to analyse data. Statistical Package for Social Scientists version 24, STATA 13 and @Risk Decision Tool were the analytical packages utilised in analysing the data. The study found that the Scheme provided low qualitative benefits, mainly through social capital. Furthermore, socio-economic and institutional factors have significant impact on the decision to participate in the Scheme, extent of participation and decision to continue practicing Scheme experiences. In comparing the two groups of Scheme and Scheme non-participants, calving and off-take risk for KyD Scheme participants was lower than that of Scheme non-participants. In comparing individuals with similar characteristics between the two groups, Scheme participants reduced calving risk whilst increasing the off-take risk. Page | vi The study concluded that the Scheme exhibited low qualitative benefits. Furthermore, the decisions to participate and the extent of participation in the KyD Scheme were influenced by various socio-economic and institutional factors, which were however more favourable to resource endowed smallholder farmers. In addition, the Scheme had significant impact on production risk. The risk reducing determinants appeared to also favour more resource endowed smallholder farmers who had more farming experience. The study’s recommendations were subdivided into short term, medium term and long term. The short term recommendations included targeting farmers within a distance of between 30km and 90km from a formal market, promoting dipping services-based training and extension, and providing information and training concerning calving i.e. animal health, husbandry and breed selection for herd maximization. Participation in the Scheme and the extent of participation can be improved through enhancing awareness of the Scheme at various points where stock feed are available to farmers. Furthermore, enhanced cooperation with extension workers provides a conduit in improving awareness of the Scheme and enhancing participation. The medium term recommendations pertained to initiatives such as promoting other livelihood options to enhance benefits of the programme, and promoting social capital enhancing initiatives such as mentoring and providing social capital objectives that can be integrated into the overall livestock sector strategy. The long-term recommendations include initiatives such as subsidizing increase in herd size to between 50 and 120 cattle, maintaining a monthly frequency of farmer-extension contact of between 2 and 5 times per month, as well as incorporating calving and off-take risk in policy formulation, implementation and evaluation
- Full Text:
- Date Issued: 2019
Evaluation of groundwater potential based on hybrid approach of geology, geophysics, and geoinformatics: Case study of Buffalo Catchment area, Eastern Cape, South Africa
- Authors: Owolabi,Solomon T
- Date: 2019
- Subjects: Hydrogeology Geology
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: http://hdl.handle.net/10353/12238 , vital:39218
- Description: This study focuses on the feasibility of exploring potential groundwater zones through assessment of catchment geo-hydrodynamic processes, using hydro-statistic principles and geographic information system-based approaches. The research work integrated analysis of hydrologic variables, geologic structures, and geomorpho-tectonic processes that provide information on spatial variability of hydrologic units in a watershed. The study is aimed at improving conceptual knowledge and presenting the technical feasibility of exploring potential groundwater zones through geo-hydrodynamic perspectives in hydrogeologically challenged environments. The study adopted a case design approach at the Buffalo hydrologic basin headwater in Eastern Cape, South Africa. The methods used in this study include: field mapping of geologic units and structures, digital processing of aeromagnetic map, cross-section profiling of borehole logs, auto-extraction of lineament, streamflow variability and recession assessment, geomorpho-tectonic analysis of surficial drainage pattern, vertical electrical sounding for imaging shallow subsurface layers, and geospatial integration of thematic maps of groundwater multi-influencing factors. The results indicate that the hydrogeological settings of Buffalo watershed comprised of good, moderate, fair, poor and very poor groundwater potential zones which cover 187 km2 , 338 km2 , 406 km2 , 185 km2 , and 121 km2 respectively. The results report that the groundwater system of Buffalo watershed is mainly hosted by the well-drained fractured dolerite and the shallow unconfined sandstone aquifer. The aquifer is bounded by two parallel impermeable valley walls in the north and south. Also, the Buffalo drainage system constitutes a variable head boundary as a groundwater discharge zone. The groundwater discharge which mostly occurs at the Tshoxa upper course, Mgqakwebe, Quencwe, Yellowwoods upper course and the Buffalo River center influence the status of the Buffalo River as a perennial river system. vi The groundwater recharge occurs through the networks of surficial lineaments and fractures concentrated on the sandstone lithosome, mostly in the northern half of the watershed. The surficial tectonic features trend in a WNW-ESE and E-W direction. The groundwater flow system is controlled by the subsurface lineaments which are oriented in west-northwest – eastsoutheast direction. Most of the groundwater recharge is driven by rain which is extreme at the north. The hydro-climatic pattern of the region influences the dendritic drainage system of Buffalo watershed. The geologic characterization and geomorpho-tectonic analysis indicate that the geologic settings are made up of upward-fining lithologic material and siliciclastic materials that were deposited as fill in paleochannels by braided and meandering fluvial systems. The variability in dissection property and the fluvial system indicates that Buffalo hydrologic and geomorphic systems are heterogeneous and complex. The possible impact of these variabilities aligns with the report of geoelectric sections which revealed the heterogeneity of the aquifer intrinsic properties and variability in groundwater yield. The electric resistivity tomography revealed the existence of a fault system and variation in the thickness of the aquifer. Hydrologic characterization indicates the vulnerability status of the rivers within the watershed. In particular, the Ngqokweni River is vulnerable to diminution while Quencwe River has the potential for a flash flood. Buffalo station is an important surface water capture zone. Delineation of groundwater potential zone should incorporate geologic, hydrologic, geophysical, geomorphotectonic, and environmental perspectives due to the inherent relationship among influencing factors. The study therefore identifies groundwater capture zones which can be further explored for groundwater development and to mitigate the stake of water shortage. The study therefore recommends the approach here to the department of water affairs for adoption to map the zones of groundwater potential at a regional scale. The study also provides resourceful information on vii groundwater recharge zones and therefore recommends that the environment and water stakeholders work together to protect the recharge zones from groundwater contamination due to land use
- Full Text:
- Date Issued: 2019
- Authors: Owolabi,Solomon T
- Date: 2019
- Subjects: Hydrogeology Geology
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: http://hdl.handle.net/10353/12238 , vital:39218
- Description: This study focuses on the feasibility of exploring potential groundwater zones through assessment of catchment geo-hydrodynamic processes, using hydro-statistic principles and geographic information system-based approaches. The research work integrated analysis of hydrologic variables, geologic structures, and geomorpho-tectonic processes that provide information on spatial variability of hydrologic units in a watershed. The study is aimed at improving conceptual knowledge and presenting the technical feasibility of exploring potential groundwater zones through geo-hydrodynamic perspectives in hydrogeologically challenged environments. The study adopted a case design approach at the Buffalo hydrologic basin headwater in Eastern Cape, South Africa. The methods used in this study include: field mapping of geologic units and structures, digital processing of aeromagnetic map, cross-section profiling of borehole logs, auto-extraction of lineament, streamflow variability and recession assessment, geomorpho-tectonic analysis of surficial drainage pattern, vertical electrical sounding for imaging shallow subsurface layers, and geospatial integration of thematic maps of groundwater multi-influencing factors. The results indicate that the hydrogeological settings of Buffalo watershed comprised of good, moderate, fair, poor and very poor groundwater potential zones which cover 187 km2 , 338 km2 , 406 km2 , 185 km2 , and 121 km2 respectively. The results report that the groundwater system of Buffalo watershed is mainly hosted by the well-drained fractured dolerite and the shallow unconfined sandstone aquifer. The aquifer is bounded by two parallel impermeable valley walls in the north and south. Also, the Buffalo drainage system constitutes a variable head boundary as a groundwater discharge zone. The groundwater discharge which mostly occurs at the Tshoxa upper course, Mgqakwebe, Quencwe, Yellowwoods upper course and the Buffalo River center influence the status of the Buffalo River as a perennial river system. vi The groundwater recharge occurs through the networks of surficial lineaments and fractures concentrated on the sandstone lithosome, mostly in the northern half of the watershed. The surficial tectonic features trend in a WNW-ESE and E-W direction. The groundwater flow system is controlled by the subsurface lineaments which are oriented in west-northwest – eastsoutheast direction. Most of the groundwater recharge is driven by rain which is extreme at the north. The hydro-climatic pattern of the region influences the dendritic drainage system of Buffalo watershed. The geologic characterization and geomorpho-tectonic analysis indicate that the geologic settings are made up of upward-fining lithologic material and siliciclastic materials that were deposited as fill in paleochannels by braided and meandering fluvial systems. The variability in dissection property and the fluvial system indicates that Buffalo hydrologic and geomorphic systems are heterogeneous and complex. The possible impact of these variabilities aligns with the report of geoelectric sections which revealed the heterogeneity of the aquifer intrinsic properties and variability in groundwater yield. The electric resistivity tomography revealed the existence of a fault system and variation in the thickness of the aquifer. Hydrologic characterization indicates the vulnerability status of the rivers within the watershed. In particular, the Ngqokweni River is vulnerable to diminution while Quencwe River has the potential for a flash flood. Buffalo station is an important surface water capture zone. Delineation of groundwater potential zone should incorporate geologic, hydrologic, geophysical, geomorphotectonic, and environmental perspectives due to the inherent relationship among influencing factors. The study therefore identifies groundwater capture zones which can be further explored for groundwater development and to mitigate the stake of water shortage. The study therefore recommends the approach here to the department of water affairs for adoption to map the zones of groundwater potential at a regional scale. The study also provides resourceful information on vii groundwater recharge zones and therefore recommends that the environment and water stakeholders work together to protect the recharge zones from groundwater contamination due to land use
- Full Text:
- Date Issued: 2019
Evaluation of pre-treatment methods on production of bioethanol from bagasse and sugarcane trash
- Authors: Dodo, Charlie Marembo
- Date: 2019
- Subjects: Lignocellulose
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15387 , vital:40403
- Description: A variety of methods have been researched on for bioethanol preparation from different feedstocks. Amongst the available feedstock, one such feedstock is the sugarcane plant. In most of the research on bioethanol preparation with sugarcane the sugary juice has been widely used, with the bagasse and trash having been discarded as waste. The “waste” bagasse and trash are usually removed and thrown away or burnt during harvesting or in sugar mills to supplement energy requirements. This research on lignocellulosic bagasse and trash was done so as not to discard them but to rather find ways in which to use this biomass constructively. Alternatives to burning that can potentially add value to this biomass need to be researched on by evaluating their hydrolysis content. The different lignocellulose pretreatment methods of concentrated and dilute acid pretreatment, with subsequent enzyme hydrolysis as well as alkali and oxidative alkali pretreatment with enzyme hydrolysis were experimented on the bagasse and trash for hydrolysis efficiency and effectiveness. There are two types of acid hydrolysis which were investigated on which are concentrated and dilute sulphuric acid pretreatments. Use of concentrated sulphuric acid yielded the highest amounts of reducing sugars but also resulted in the highest amounts of downstream process inhibitors formation. This resulted in the need for neutralisation steps which in turn increase the overall costs of using this method to obtain reducing sugars. It has however the advantage of occurring at a faster rate, within minutes or hours, than using biological enzymes which took days, up to 72 hours to obtain the highest reducing sugar amounts. Dilute sulphuric acid pretreatment offered the advantage of using fewer chemicals which are therefore less severe on equipment and result in fewer fermentation inhibitors being formed. Dilute sulphuric acid hydrolysis also takes a relatively shorter period than biological methods of pretreatment. A challenge of fermentation inhibitors formed during acid hydrolysis was countered by using the methods of overliming (calcium hydroxide) and comparing it to neutralization with sodium hydroxide. Alkali pretreatment with sodium hydroxide was researched on by applying different pretreatment concentrations during experiments on the lignocellulosic biomass. There was an increase in the available quantities of cellulose with a significant reduction in lignin with pretreatment. Alkali pretreatment proved effective in exposing the cellulose which made v more cellulose surface area available to cellulase enzymes for enzyme hydrolysis. The highest yield of reducing sugars was obtained from hydrolysates pretreated with 0.25 M sodium hydroxide for 60 min and a period of 72 h of enzyme hydrolysis. In general the longer the pretreatment time the more reducing sugars were produced from the enzyme hydrolysis. Alkali peroxide pretreatment also resulted in significant reductions in lignin quantities of lignocellulose material. In this method sodium hydroxide in combination with hydrogen peroxide were used in pretreating the biomass. Hydrolysates with even fewer fermentation inhibitors were produced as a result. The highest percentage concentration of cellulose of 63% (g/g) was achieved after pretreatment of bagasse with 5% alkali hydrogen peroxide and trash with 0,25M sodium hydroxide pretreatment. Pretreatment of biomass using alkali with subsequent enzymatic hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) alkali peroxide pre-treated trash than 36% (g/g) for 5% (v/v) with the least inhibitors. Reducing sugar yields of 25% (g/g) and 22% (g/g) were obtained after pretreatment with concentrated and dilute acid respectively. Neutralization of the acid hydrolysates was necessary to reduce inhibitors formed with neutralisation by sodium hydroxide resulting in low dilutions and loss of fermentable sugars as unlike in the case of overliming. Subsequent steps of fermenting the reducing sugars resulting from pretreatment into bioethanol were based on using the yeast Saccharomyces cerevisae. Pretreatment hydrolysates from alkali peroxide experiments produced higher bioethanol yields of 13.7 (g/l) after enzyme hydrolysates versus 6.9 (g/l) bioethanol from dilute acid hydrolyzates. A comparison of the effects of time showed there was more bioethanol yield of 13.7 (g/l) after 72 h of fermentation with the yeast versus 7.0 (g/l) bioethanol after pretreatment for 24 h. The only drawback is the longer fermentation period which thus reduces the process and so reduces the value of the increase in yield
- Full Text:
- Date Issued: 2019
- Authors: Dodo, Charlie Marembo
- Date: 2019
- Subjects: Lignocellulose
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15387 , vital:40403
- Description: A variety of methods have been researched on for bioethanol preparation from different feedstocks. Amongst the available feedstock, one such feedstock is the sugarcane plant. In most of the research on bioethanol preparation with sugarcane the sugary juice has been widely used, with the bagasse and trash having been discarded as waste. The “waste” bagasse and trash are usually removed and thrown away or burnt during harvesting or in sugar mills to supplement energy requirements. This research on lignocellulosic bagasse and trash was done so as not to discard them but to rather find ways in which to use this biomass constructively. Alternatives to burning that can potentially add value to this biomass need to be researched on by evaluating their hydrolysis content. The different lignocellulose pretreatment methods of concentrated and dilute acid pretreatment, with subsequent enzyme hydrolysis as well as alkali and oxidative alkali pretreatment with enzyme hydrolysis were experimented on the bagasse and trash for hydrolysis efficiency and effectiveness. There are two types of acid hydrolysis which were investigated on which are concentrated and dilute sulphuric acid pretreatments. Use of concentrated sulphuric acid yielded the highest amounts of reducing sugars but also resulted in the highest amounts of downstream process inhibitors formation. This resulted in the need for neutralisation steps which in turn increase the overall costs of using this method to obtain reducing sugars. It has however the advantage of occurring at a faster rate, within minutes or hours, than using biological enzymes which took days, up to 72 hours to obtain the highest reducing sugar amounts. Dilute sulphuric acid pretreatment offered the advantage of using fewer chemicals which are therefore less severe on equipment and result in fewer fermentation inhibitors being formed. Dilute sulphuric acid hydrolysis also takes a relatively shorter period than biological methods of pretreatment. A challenge of fermentation inhibitors formed during acid hydrolysis was countered by using the methods of overliming (calcium hydroxide) and comparing it to neutralization with sodium hydroxide. Alkali pretreatment with sodium hydroxide was researched on by applying different pretreatment concentrations during experiments on the lignocellulosic biomass. There was an increase in the available quantities of cellulose with a significant reduction in lignin with pretreatment. Alkali pretreatment proved effective in exposing the cellulose which made v more cellulose surface area available to cellulase enzymes for enzyme hydrolysis. The highest yield of reducing sugars was obtained from hydrolysates pretreated with 0.25 M sodium hydroxide for 60 min and a period of 72 h of enzyme hydrolysis. In general the longer the pretreatment time the more reducing sugars were produced from the enzyme hydrolysis. Alkali peroxide pretreatment also resulted in significant reductions in lignin quantities of lignocellulose material. In this method sodium hydroxide in combination with hydrogen peroxide were used in pretreating the biomass. Hydrolysates with even fewer fermentation inhibitors were produced as a result. The highest percentage concentration of cellulose of 63% (g/g) was achieved after pretreatment of bagasse with 5% alkali hydrogen peroxide and trash with 0,25M sodium hydroxide pretreatment. Pretreatment of biomass using alkali with subsequent enzymatic hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) alkali peroxide pre-treated trash than 36% (g/g) for 5% (v/v) with the least inhibitors. Reducing sugar yields of 25% (g/g) and 22% (g/g) were obtained after pretreatment with concentrated and dilute acid respectively. Neutralization of the acid hydrolysates was necessary to reduce inhibitors formed with neutralisation by sodium hydroxide resulting in low dilutions and loss of fermentable sugars as unlike in the case of overliming. Subsequent steps of fermenting the reducing sugars resulting from pretreatment into bioethanol were based on using the yeast Saccharomyces cerevisae. Pretreatment hydrolysates from alkali peroxide experiments produced higher bioethanol yields of 13.7 (g/l) after enzyme hydrolysates versus 6.9 (g/l) bioethanol from dilute acid hydrolyzates. A comparison of the effects of time showed there was more bioethanol yield of 13.7 (g/l) after 72 h of fermentation with the yeast versus 7.0 (g/l) bioethanol after pretreatment for 24 h. The only drawback is the longer fermentation period which thus reduces the process and so reduces the value of the increase in yield
- Full Text:
- Date Issued: 2019
Examination of teacher mediation and its impact on foundational reading skills in Grade-R classrooms in Namibia
- Authors: Nzwala, Kenneth
- Date: 2019
- Subjects: Reading (Elementary) -- Namibia -- Case studies , Elementary school teachers -- Namibia -- Case studies , Early childhood education -- Curricula -- Namibia , Vygotskiĭ, L. S. (Lev Semenovich), 1896-1934
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92291 , vital:30700
- Description: Grounded in the Sociocultural Theory (SCT) of Lev Vygotsky, this study examined teacher mediation and its impact on development of foundational reading skills in six Grade-R classrooms in the Zambezi Region of Namibia. It was a multiple case study with a mixed methods approach. Six Grade R classes attached to primary schools were studied to facilitate following of the same learners to Grade One. A purposive sampling technique was used to draw a sample of six Grade-R and Grade-One teachers. Learners were selected using stratified random sampling. Data were collected by means of interviews, observation of Grade R lessons, and an emergent Early Grade Reading Assessment (eEGRA) test. eEGRA facilitated benchmarking teacher efficacy in mediating Grade R learners’ foundational reading skills. Nine Grade One learners per teacher per school took part in the test at the beginning of Grade One. Three 35-minute lessons, per Grade-R teacher, were observed. Data were analysed statistically using ANOVA with thematic qualitative analysis of interview data against document analysis of curricula, teacher planning and learner exercise books. The study established that teachers had no understanding of ‘emergent literacy’, did not promote a love of books, or promote learning through play. There was evidence of a language barrier during lessons, which potentially reduced the efficacy of teacher mediation. The curriculum was found to be inappropriate as it lacked guidance relevant to Grade R teachers. This point was particularly pertinent as all teachers in this study had not received Grade-R training and were therefore looking to the curriculum for support. The difference between what teachers said and what they did was revealed in their classroom practice. Lesson planning was found to be superficial and non-reflective, with a marked discrepancy between what was planned and what was done. The style of pedagogy was primarily transmissive and authoritarian. Finally, the socio-economic distribution of the schools did not demonstrate significant impact on learner performance in the benchmark test. This study concludes that the Grade-R curriculum needs to be revised to be culturally and age appropriate. Teachers should be trained to understand the speciality of Grade R, and support should be given to current teachers to adopt a child-centred, play-based approach to pedagogy.
- Full Text:
- Date Issued: 2019
- Authors: Nzwala, Kenneth
- Date: 2019
- Subjects: Reading (Elementary) -- Namibia -- Case studies , Elementary school teachers -- Namibia -- Case studies , Early childhood education -- Curricula -- Namibia , Vygotskiĭ, L. S. (Lev Semenovich), 1896-1934
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92291 , vital:30700
- Description: Grounded in the Sociocultural Theory (SCT) of Lev Vygotsky, this study examined teacher mediation and its impact on development of foundational reading skills in six Grade-R classrooms in the Zambezi Region of Namibia. It was a multiple case study with a mixed methods approach. Six Grade R classes attached to primary schools were studied to facilitate following of the same learners to Grade One. A purposive sampling technique was used to draw a sample of six Grade-R and Grade-One teachers. Learners were selected using stratified random sampling. Data were collected by means of interviews, observation of Grade R lessons, and an emergent Early Grade Reading Assessment (eEGRA) test. eEGRA facilitated benchmarking teacher efficacy in mediating Grade R learners’ foundational reading skills. Nine Grade One learners per teacher per school took part in the test at the beginning of Grade One. Three 35-minute lessons, per Grade-R teacher, were observed. Data were analysed statistically using ANOVA with thematic qualitative analysis of interview data against document analysis of curricula, teacher planning and learner exercise books. The study established that teachers had no understanding of ‘emergent literacy’, did not promote a love of books, or promote learning through play. There was evidence of a language barrier during lessons, which potentially reduced the efficacy of teacher mediation. The curriculum was found to be inappropriate as it lacked guidance relevant to Grade R teachers. This point was particularly pertinent as all teachers in this study had not received Grade-R training and were therefore looking to the curriculum for support. The difference between what teachers said and what they did was revealed in their classroom practice. Lesson planning was found to be superficial and non-reflective, with a marked discrepancy between what was planned and what was done. The style of pedagogy was primarily transmissive and authoritarian. Finally, the socio-economic distribution of the schools did not demonstrate significant impact on learner performance in the benchmark test. This study concludes that the Grade-R curriculum needs to be revised to be culturally and age appropriate. Teachers should be trained to understand the speciality of Grade R, and support should be given to current teachers to adopt a child-centred, play-based approach to pedagogy.
- Full Text:
- Date Issued: 2019
Examining educators’ strategies for promoting science learning and science literacy among grade 9 learners in a South African Rural Education District
- Authors: Mtsi, Nomxolisi
- Date: 2019
- Subjects: Science -- Study and teaching (Elementary) Children's literature in science education
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/16150 , vital:40673
- Description: Science learning and Science Literacy (SL) play a crucial role in preparing learners to participate in the country’s economy with the relevant knowledge, higher order thinking and analytical reasoning to solve day-to-day problems. The purpose of this research was to examine educators’ strategies for promoting science learning and SL among grade 9 learners in a rural education district in South Africa’s Eastern Cape Province. Learning of science and promotion of SL complement each other and therefore science educators’ strategies are pertinent. The study used pragmatic paradigm and the mixed method approach and was informed by cognitive and social constructivism as theoretical frameworks. For data collection, the study used convenience sampling based on the proximity and comparative ease of the researcher to reach the rural schools to select 30 out of 67 schools spread over six out of the eight circuits in the selected education district. On the other hand, purposive sampling was used for the selection of learners by their educators based on academic performance, top, average and below average achievers. Since each school had only one grade 9 science educator, 30 grade 9 science educators from the selected 30 schools formed the sample for quantitative data. Out of these 30, 10 educators who volunteered first for interviews and gave permission for being observed in their classrooms were selected for qualitative data collection. Three learners in each of the 10 schools from which the educators for qualitative data collection were selected, constituted the learners’ sample (30 learners). While data were collected through questionnaires, interviews and observations from educators, data from learners were collected through focus group (FG) interviews. The questionnaire was structured in order to gather educators’ biographical data as well as information on educators’ strategies to promote science learning and SL. The interview schedule was similar to the questionnaire but biographical data were excluded. Observations focused on educators’ strategies for science learning, SL and assessments. The data from the questionnaire were descriptively analysed and the qualitative and transcribed observation data were thematically analysed. Final conclusions were drawn based on the triangulated data. Major findings showed that the strategies which the educators employed in the descending order of use were: Investigation at 97percent; Discussion, Presentation and Project, each at 93percent; Problem solving at 90percent; Demonstration and Question-Answer, each at 87percent; Case study and Brainstorming, each at 77percent; Role-play at 63percent; Lecture at 57percent; Modelling at 47percent, Inquiry at 27percent and Simulation at 23percent. Findings also revealed the strengths and weaknesses of the strategies used by educators. Some of the strengths were: promotion of interactive learning; stimulation of research skills; enhancement of critical thinking and development of confidence through participation. Some of the weaknesses were: learners’ tendency to rely on others; lack of resources hindering learning and promotion of plagiarism. The study recommends that all stakeholders must work together to achieve good quality education. District and Provincial officers ought to track and monitor the science curriculum implementation. Subject specialists, educator subject committees and cluster leaders must also be active in strategic planning for enhancing SL in schools by putting forward their inputs and adopting consensus-based ones. A framework for driving science content with pedagogical content knowledge and practicals-driven strategy for enhancing science content knowledge is proposed.
- Full Text:
- Date Issued: 2019
- Authors: Mtsi, Nomxolisi
- Date: 2019
- Subjects: Science -- Study and teaching (Elementary) Children's literature in science education
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/16150 , vital:40673
- Description: Science learning and Science Literacy (SL) play a crucial role in preparing learners to participate in the country’s economy with the relevant knowledge, higher order thinking and analytical reasoning to solve day-to-day problems. The purpose of this research was to examine educators’ strategies for promoting science learning and SL among grade 9 learners in a rural education district in South Africa’s Eastern Cape Province. Learning of science and promotion of SL complement each other and therefore science educators’ strategies are pertinent. The study used pragmatic paradigm and the mixed method approach and was informed by cognitive and social constructivism as theoretical frameworks. For data collection, the study used convenience sampling based on the proximity and comparative ease of the researcher to reach the rural schools to select 30 out of 67 schools spread over six out of the eight circuits in the selected education district. On the other hand, purposive sampling was used for the selection of learners by their educators based on academic performance, top, average and below average achievers. Since each school had only one grade 9 science educator, 30 grade 9 science educators from the selected 30 schools formed the sample for quantitative data. Out of these 30, 10 educators who volunteered first for interviews and gave permission for being observed in their classrooms were selected for qualitative data collection. Three learners in each of the 10 schools from which the educators for qualitative data collection were selected, constituted the learners’ sample (30 learners). While data were collected through questionnaires, interviews and observations from educators, data from learners were collected through focus group (FG) interviews. The questionnaire was structured in order to gather educators’ biographical data as well as information on educators’ strategies to promote science learning and SL. The interview schedule was similar to the questionnaire but biographical data were excluded. Observations focused on educators’ strategies for science learning, SL and assessments. The data from the questionnaire were descriptively analysed and the qualitative and transcribed observation data were thematically analysed. Final conclusions were drawn based on the triangulated data. Major findings showed that the strategies which the educators employed in the descending order of use were: Investigation at 97percent; Discussion, Presentation and Project, each at 93percent; Problem solving at 90percent; Demonstration and Question-Answer, each at 87percent; Case study and Brainstorming, each at 77percent; Role-play at 63percent; Lecture at 57percent; Modelling at 47percent, Inquiry at 27percent and Simulation at 23percent. Findings also revealed the strengths and weaknesses of the strategies used by educators. Some of the strengths were: promotion of interactive learning; stimulation of research skills; enhancement of critical thinking and development of confidence through participation. Some of the weaknesses were: learners’ tendency to rely on others; lack of resources hindering learning and promotion of plagiarism. The study recommends that all stakeholders must work together to achieve good quality education. District and Provincial officers ought to track and monitor the science curriculum implementation. Subject specialists, educator subject committees and cluster leaders must also be active in strategic planning for enhancing SL in schools by putting forward their inputs and adopting consensus-based ones. A framework for driving science content with pedagogical content knowledge and practicals-driven strategy for enhancing science content knowledge is proposed.
- Full Text:
- Date Issued: 2019
Examining mathematical reasoning through enacted visualisation
- Authors: Dongwi, Beata Lididimikeni
- Date: 2019
- Subjects: Visualization , Mathematics -- Study and teaching -- Namibia , Mathematics -- Study and teaching -- Audio-visual aids , Geometry -- Study and teaching , Reasoning , Mathematical ability
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68192 , vital:29217
- Description: This study sets out to analyse the co-emergence of visualisation and reasoning processes when selected learners engaged in solving word problems. The study argues that visualisation processes and mathematical reasoning processes are closely interlinked in the process of engaging in any mathematical activity. This qualitative research project adopted a case study methodology embedded within a broader interpretative orientation. The research participants were a cohort of 17 mixedgender and mixed-ability Grade 11 learners from a private school in southern Namibia. Data was collected in three phases and comprised of one-on-one task-based interviews in the first phase, focus group task-based interviews in the second, and semi-structured reflective interviews in the third. The analytical framework was informed by elements of enactivism and consisted of a hybrid of observable visualisation and mathematical reasoning indicators. The study was framed by an enactivist perspective that served as a linking mediator to bring visualisation and reasoning processes together, and as a lens through which the coemergence of these processes was observed and analysed. The key enactivist concepts of structural coupling and co-emergence were the two mediating ideas that enabled me to discuss the links between visualisation and reasoning that emerged whilst my participants solved the set word problems. The study argues that the visualisation processes enacted by the participants when solving these problems are inseparable from the reasoning processes that the participants brought to bear; that is, they co-emerged.
- Full Text:
- Date Issued: 2019
- Authors: Dongwi, Beata Lididimikeni
- Date: 2019
- Subjects: Visualization , Mathematics -- Study and teaching -- Namibia , Mathematics -- Study and teaching -- Audio-visual aids , Geometry -- Study and teaching , Reasoning , Mathematical ability
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68192 , vital:29217
- Description: This study sets out to analyse the co-emergence of visualisation and reasoning processes when selected learners engaged in solving word problems. The study argues that visualisation processes and mathematical reasoning processes are closely interlinked in the process of engaging in any mathematical activity. This qualitative research project adopted a case study methodology embedded within a broader interpretative orientation. The research participants were a cohort of 17 mixedgender and mixed-ability Grade 11 learners from a private school in southern Namibia. Data was collected in three phases and comprised of one-on-one task-based interviews in the first phase, focus group task-based interviews in the second, and semi-structured reflective interviews in the third. The analytical framework was informed by elements of enactivism and consisted of a hybrid of observable visualisation and mathematical reasoning indicators. The study was framed by an enactivist perspective that served as a linking mediator to bring visualisation and reasoning processes together, and as a lens through which the coemergence of these processes was observed and analysed. The key enactivist concepts of structural coupling and co-emergence were the two mediating ideas that enabled me to discuss the links between visualisation and reasoning that emerged whilst my participants solved the set word problems. The study argues that the visualisation processes enacted by the participants when solving these problems are inseparable from the reasoning processes that the participants brought to bear; that is, they co-emerged.
- Full Text:
- Date Issued: 2019
Examining the teaching of natural sciences concepts to English second language speakers in selected primary schools in the East London Education District
- Authors: Kumanda, Nomaroma
- Date: 2019
- Subjects: Science -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15925 , vital:40564
- Description: The study sought to examine the teaching of Natural Sciences (NS) concepts to English second language speakers in selected primary schools. Grade 7 was chosen for the investigation as it precedes the last class at primary school. The researcher investigated the teaching and learning of Natural sciences concepts. A mixed method design was used. The research questions focused on the teaching of NS, learner-centred strategies used, challenges encountered, strategies employed by teachers when teaching NS, and the implications for science education.The purpose was to examine the teaching of Natural Sciences concepts to English second language speakers in selected primary schools in the East London Education District. Data were collected from grade 7 teachers and learners in selected township schools in East London, by means of semi-structured interviews, questionnaires and focus groups. Semi-structured questionnaires were administered to teachers and learners, individual interviews were conducted with NS head of department, focus group and interviews were held with grade 7 NS learners. Quantitative and qualitative data were independently analysed and merged at the interpretation stage for triangulation of results. The questions were grouped according to their themes. The researcher’s findings revealed that teachers linked the teaching of NS concepts by showing the teaching skills. Teachers used code-switching for learners to understand the scientific concepts for positive attitude to improve the learner performance. Teachers experienced problems using English as a Language of Learning and Teaching (LoLT) while teaching NS concepts, teachers’ understanding of NS influenced their ability to implement of transformational curriculum, but learners did not benefit much when learning science in English Language and those policies were designed by the Department of Education without teacher involvement. The study concluded by noting that It emerged that teachers and learners experienced difficulties in teaching and learning of the NS concepts.
- Full Text:
- Date Issued: 2019
- Authors: Kumanda, Nomaroma
- Date: 2019
- Subjects: Science -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15925 , vital:40564
- Description: The study sought to examine the teaching of Natural Sciences (NS) concepts to English second language speakers in selected primary schools. Grade 7 was chosen for the investigation as it precedes the last class at primary school. The researcher investigated the teaching and learning of Natural sciences concepts. A mixed method design was used. The research questions focused on the teaching of NS, learner-centred strategies used, challenges encountered, strategies employed by teachers when teaching NS, and the implications for science education.The purpose was to examine the teaching of Natural Sciences concepts to English second language speakers in selected primary schools in the East London Education District. Data were collected from grade 7 teachers and learners in selected township schools in East London, by means of semi-structured interviews, questionnaires and focus groups. Semi-structured questionnaires were administered to teachers and learners, individual interviews were conducted with NS head of department, focus group and interviews were held with grade 7 NS learners. Quantitative and qualitative data were independently analysed and merged at the interpretation stage for triangulation of results. The questions were grouped according to their themes. The researcher’s findings revealed that teachers linked the teaching of NS concepts by showing the teaching skills. Teachers used code-switching for learners to understand the scientific concepts for positive attitude to improve the learner performance. Teachers experienced problems using English as a Language of Learning and Teaching (LoLT) while teaching NS concepts, teachers’ understanding of NS influenced their ability to implement of transformational curriculum, but learners did not benefit much when learning science in English Language and those policies were designed by the Department of Education without teacher involvement. The study concluded by noting that It emerged that teachers and learners experienced difficulties in teaching and learning of the NS concepts.
- Full Text:
- Date Issued: 2019
Expanding learning in clergy leadership formation in an Anglican Church Province in Southern Africa: a critical realist study
- Authors: Chinganga, Percy
- Date: 2019
- Subjects: Leadership -- Africa, Southern -- Religious aspects -- Christianity , Church management -- Africa, Southern , Critical realism , Educational leadership , Anglican Church of Southern Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92258 , vital:30704
- Description: The focus of this study was to investigate the kind of learning that happened when participants involved in clergy leadership formation programmes and activities in the Anglican Church of Southern Africa (ACSA) engaged in their responsibilities as a collective. Further, the research sought to explore collaborative and transforming practices in ACSA clergy leadership formation programmes and activities which could be expanded through learning. The study is premised on an investigation of the historical foundations of Christian leadership formation processes which sought to establish clergy leadership formation models relevant to ACSA (the context of the study) from inception (1848) to date (2017). This entailed investigating how the developments which have happened in the church from its inception in the New Testament times through the Medieval and Reformation periods, have contributed to the emergence of distinct Christian leadership formation models which have formed the basis of clergy leadership formation in ACSA. Accordingly, the study highlighted key issues relating to clergy leadership formation which are discernible in the different historical phases of the life and work of the church with the objective of establishing how ACSA, through expansive learning, could transform her current clergy leadership formation model(s) towards collaborative and transforming practices. The concept of expansive learning, drawn from Cultural Historical Activity Theory (CHAT), was used in the study as a methodological tool to create an environment where research participants (formators) from several dioceses would engage in collective work activities which would surface contradictions relating to how clergy leadership formation programmes and activities were understood and facilitated in ACSA. In response to the surfaced contradictions, the study engaged research participants in Change Laboratory Workshops whose goal was to transform the organisation (ACSA) in two particular ways: empowerment of participants (formators) with conceptual tools relevant to their responsibilities in clergy leadership formation programmes and activities in ACSA, and improvement of organisational cultural practices, that is, the manner in which ACSA ought to conceptualise, design, plan, facilitate and manage clergy leadership formation programmes and activities. The latter brought into the discourse the need for participants (formators) to select and employ methodologies, methods, approaches and resources relevant to the southern African context where ACSA is located even though the study also acknowledged the influence of other Anglican Church contexts on what happened at the local level. In order to decipher meaning out of investigated phenomena about clergy leadership formation in ACSA, the study employed the critical realist “underlabouring” philosophy advanced by theorists such as Bhaskar to surface underlying mechanisms that exist at the level of the “real” in order to understand the causes of particular events and experiences as they manifest in the “actual” and “empirical” domains of the world, ACSA in the case of the study. In particular, the study engaged critically the opinion deliberated by critical realists concerning the interplay between structure and agency in relation to the responsibilities of the research participants (formators) in ACSA clergy leadership formation programmes and activities. For instance, the study had an interest in investigating why bishops (principal formators in ACSA) exercised their episcopal authority in the manner they do and why individual formators were concerned about particular issues which relate to the facilitation of clergy leadership formation in ACSA (agential reflexivity/subjectivity). The study observed that, in the case of diocesan bishops, critical realists would argue that, by virtue of the authority which comes with their responsibilities (agency), they have the power to influence transformation of practices in clergy leadership formation in ACSA at any given point in time. The flip side of the discourse was also taken note of: that some bishops, for reasons known to themselves and their predecessors, are often reluctant to embrace new ideas relating to clergy leadership formation practices in their dioceses. Further, through critical realist lens, the study concluded that Canons, Vision and Mission statements, Acts, and structures such as Synod of Bishops, Provincial Synod, ABoTE, Cott, and TfM structurally shape ACSA, thus providing the organisation with a stable ontology which ought to direct, regulate and control the manner in which clergy leadership formation programmes and activities were conceptualised, designed, planned, facilitated and managed. As such, the study had an interest in establishing what would happen, in relation to clergy leadership formation practices in ACSA, when these structures would have been activated? Beyond that, in view of the goal of the study, it was enquired how expansive learning processes could be helpful in responding to the research findings towards exploring collaborative and transforming clergy leadership formation practices in ACSA. Drawing from the conceptual framework which was carved in the study on the basis of the theoretical tools (critical realism and educational leadership theory) and methodological tools (CHAT orientated concepts) undergirded by the Vygotskian theorisation of human consciousness development, the study concluded that clergy leadership formation is a collaborative activity which calls for the recognition, appreciation and utilisation of available expertise in ACSA and provision of a platform where participants (formators) could engage collectively on issues relating to their work with the objective of building each other up in knowledge and skills (expansive learning) towards realisation of the goals and objectives of the organisation. Diverse understandings (contradictions) of what needed to be prioritised in the facilitation of clergy leadership formation in ACSA would be considered as a positive rather than a negative. Ultimately, through the use of inductive, abductive and retroductive modes of inference, the study modelled a transforming, transformational, transformative, embodied and incarnational model of clergy leadership formation which ACSA could consider using in future deliberations on the object of study particularly in relation to the key research findings across the case studies which were used in the study.
- Full Text:
- Date Issued: 2019
- Authors: Chinganga, Percy
- Date: 2019
- Subjects: Leadership -- Africa, Southern -- Religious aspects -- Christianity , Church management -- Africa, Southern , Critical realism , Educational leadership , Anglican Church of Southern Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92258 , vital:30704
- Description: The focus of this study was to investigate the kind of learning that happened when participants involved in clergy leadership formation programmes and activities in the Anglican Church of Southern Africa (ACSA) engaged in their responsibilities as a collective. Further, the research sought to explore collaborative and transforming practices in ACSA clergy leadership formation programmes and activities which could be expanded through learning. The study is premised on an investigation of the historical foundations of Christian leadership formation processes which sought to establish clergy leadership formation models relevant to ACSA (the context of the study) from inception (1848) to date (2017). This entailed investigating how the developments which have happened in the church from its inception in the New Testament times through the Medieval and Reformation periods, have contributed to the emergence of distinct Christian leadership formation models which have formed the basis of clergy leadership formation in ACSA. Accordingly, the study highlighted key issues relating to clergy leadership formation which are discernible in the different historical phases of the life and work of the church with the objective of establishing how ACSA, through expansive learning, could transform her current clergy leadership formation model(s) towards collaborative and transforming practices. The concept of expansive learning, drawn from Cultural Historical Activity Theory (CHAT), was used in the study as a methodological tool to create an environment where research participants (formators) from several dioceses would engage in collective work activities which would surface contradictions relating to how clergy leadership formation programmes and activities were understood and facilitated in ACSA. In response to the surfaced contradictions, the study engaged research participants in Change Laboratory Workshops whose goal was to transform the organisation (ACSA) in two particular ways: empowerment of participants (formators) with conceptual tools relevant to their responsibilities in clergy leadership formation programmes and activities in ACSA, and improvement of organisational cultural practices, that is, the manner in which ACSA ought to conceptualise, design, plan, facilitate and manage clergy leadership formation programmes and activities. The latter brought into the discourse the need for participants (formators) to select and employ methodologies, methods, approaches and resources relevant to the southern African context where ACSA is located even though the study also acknowledged the influence of other Anglican Church contexts on what happened at the local level. In order to decipher meaning out of investigated phenomena about clergy leadership formation in ACSA, the study employed the critical realist “underlabouring” philosophy advanced by theorists such as Bhaskar to surface underlying mechanisms that exist at the level of the “real” in order to understand the causes of particular events and experiences as they manifest in the “actual” and “empirical” domains of the world, ACSA in the case of the study. In particular, the study engaged critically the opinion deliberated by critical realists concerning the interplay between structure and agency in relation to the responsibilities of the research participants (formators) in ACSA clergy leadership formation programmes and activities. For instance, the study had an interest in investigating why bishops (principal formators in ACSA) exercised their episcopal authority in the manner they do and why individual formators were concerned about particular issues which relate to the facilitation of clergy leadership formation in ACSA (agential reflexivity/subjectivity). The study observed that, in the case of diocesan bishops, critical realists would argue that, by virtue of the authority which comes with their responsibilities (agency), they have the power to influence transformation of practices in clergy leadership formation in ACSA at any given point in time. The flip side of the discourse was also taken note of: that some bishops, for reasons known to themselves and their predecessors, are often reluctant to embrace new ideas relating to clergy leadership formation practices in their dioceses. Further, through critical realist lens, the study concluded that Canons, Vision and Mission statements, Acts, and structures such as Synod of Bishops, Provincial Synod, ABoTE, Cott, and TfM structurally shape ACSA, thus providing the organisation with a stable ontology which ought to direct, regulate and control the manner in which clergy leadership formation programmes and activities were conceptualised, designed, planned, facilitated and managed. As such, the study had an interest in establishing what would happen, in relation to clergy leadership formation practices in ACSA, when these structures would have been activated? Beyond that, in view of the goal of the study, it was enquired how expansive learning processes could be helpful in responding to the research findings towards exploring collaborative and transforming clergy leadership formation practices in ACSA. Drawing from the conceptual framework which was carved in the study on the basis of the theoretical tools (critical realism and educational leadership theory) and methodological tools (CHAT orientated concepts) undergirded by the Vygotskian theorisation of human consciousness development, the study concluded that clergy leadership formation is a collaborative activity which calls for the recognition, appreciation and utilisation of available expertise in ACSA and provision of a platform where participants (formators) could engage collectively on issues relating to their work with the objective of building each other up in knowledge and skills (expansive learning) towards realisation of the goals and objectives of the organisation. Diverse understandings (contradictions) of what needed to be prioritised in the facilitation of clergy leadership formation in ACSA would be considered as a positive rather than a negative. Ultimately, through the use of inductive, abductive and retroductive modes of inference, the study modelled a transforming, transformational, transformative, embodied and incarnational model of clergy leadership formation which ACSA could consider using in future deliberations on the object of study particularly in relation to the key research findings across the case studies which were used in the study.
- Full Text:
- Date Issued: 2019
Exploring emotional intelligence perceptions of school leaders in relation to social justice: a case study
- Authors: Bese, Samuel
- Date: 2019
- Subjects: Educational leadership
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/36529 , vital:33963
- Description: The aim of this study was to explore school leaders’ perceptions of intrapersonal and interpersonal emotional intelligence (EI) in relation to social justice aspects, such as equity, access and inclusive participation in the Libode Educational District of Eastern Cape Province. This district, like many other rural districts in South Africa, has to face critical leadership issues, which have an influence on how school leaders could enact social justice practices in schools (DoE, 2012). This qualitative study employed twelve in-depth interview research participants, which included 6 purposively selected principals and 6 deputy principals. Data collection and content analysis also included the following: 6 focus group interviews with head of departments (HODs) and school governing bodies (SGBs); document analysis of the minutes of school meetings; and Department of Education (DoE) memorandums. The key findings that emerged through the descriptive, exploratory, social interpretive perspectives used in this study revealed the relevance of: • school leaders’ perceptions of intrapersonal EI in enhancing social justice practices with regard to equity, access, and inclusive participation; and • school leaders’ perceptions of interpersonal EI in enhancing social justice practices with regard to equity, access, and inclusive participation. The research participants’ perceptions of EI promoted deeper understanding of how school leaders could engage in social justice in relation to school leadership, teamwork, building bonds, developing others, becoming change agents, and managing conflicts in their schools. The study also captured that EI leaders can greatly manage their emotions to enhance their abilities to identify and control their destructive impulses as well as understanding and handling others’ emotions. It would be commendable for school leaders to have a deeper understanding of how their emotions could enhance social justice in their schools.
- Full Text:
- Date Issued: 2019
- Authors: Bese, Samuel
- Date: 2019
- Subjects: Educational leadership
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/36529 , vital:33963
- Description: The aim of this study was to explore school leaders’ perceptions of intrapersonal and interpersonal emotional intelligence (EI) in relation to social justice aspects, such as equity, access and inclusive participation in the Libode Educational District of Eastern Cape Province. This district, like many other rural districts in South Africa, has to face critical leadership issues, which have an influence on how school leaders could enact social justice practices in schools (DoE, 2012). This qualitative study employed twelve in-depth interview research participants, which included 6 purposively selected principals and 6 deputy principals. Data collection and content analysis also included the following: 6 focus group interviews with head of departments (HODs) and school governing bodies (SGBs); document analysis of the minutes of school meetings; and Department of Education (DoE) memorandums. The key findings that emerged through the descriptive, exploratory, social interpretive perspectives used in this study revealed the relevance of: • school leaders’ perceptions of intrapersonal EI in enhancing social justice practices with regard to equity, access, and inclusive participation; and • school leaders’ perceptions of interpersonal EI in enhancing social justice practices with regard to equity, access, and inclusive participation. The research participants’ perceptions of EI promoted deeper understanding of how school leaders could engage in social justice in relation to school leadership, teamwork, building bonds, developing others, becoming change agents, and managing conflicts in their schools. The study also captured that EI leaders can greatly manage their emotions to enhance their abilities to identify and control their destructive impulses as well as understanding and handling others’ emotions. It would be commendable for school leaders to have a deeper understanding of how their emotions could enhance social justice in their schools.
- Full Text:
- Date Issued: 2019
Exploring the interplay of sociolinguistic factors in the teaching of esl at secondary school level in Zimbabwe
- Authors: Jhamba , Duren
- Date: 2019
- Subjects: Sociolinguistics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15770 , vital:40522
- Description: The researcher noted that earlier second language teaching models tended to treat language as an artefact to be scrutinised and adhered to with grammatical precision. This tended to reduce all language learning to the mere acquisition of grammatical skills. However, since all language behaviour is embedded in sociocultural and contextual frameworks, all teaching should provide cross-cultural awareness of that complexity as well as of the internal variation within language. Therefore, the research explored the interplay of sociolinguistic factors in the teaching of English in Zimbabwe. The Mixed Methods design; a combination of the descriptive survey and the case study was adopted. The questionnaire, interview, observation and document analysis methods were used to collect both qualitative and quantitative data to assess the role of sociolinguistic factors in second language teaching pedagogy. A combination of convenient sampling and stratified random sampling was used to come up with a sample representative of the school categories and the gender of teachers in the 38 secondary schools in Gweru District. The data for the research was collected from a random sample of 50 teachers. The data analysis supported the need for a reconceptualisation of ESL teaching in Zimbabwe. Notably, language teaching tended to be exam-centric, unimaginative and not well linked to the needs of the learners in the communicative environment outside the school. This confirmed the initial observation that the secondary school graduates generally lacked sociolinguistic competence skills. The teachers were, however generally not motivated to include culture and sociolinguistics in their teaching. The research therefore recommended a revisit of the 7 | Page allowance for the interplay of sociolinguistic factors at all the planning stages of the ESL curriculum; the status, corpus and acquisition stages.
- Full Text:
- Date Issued: 2019
- Authors: Jhamba , Duren
- Date: 2019
- Subjects: Sociolinguistics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15770 , vital:40522
- Description: The researcher noted that earlier second language teaching models tended to treat language as an artefact to be scrutinised and adhered to with grammatical precision. This tended to reduce all language learning to the mere acquisition of grammatical skills. However, since all language behaviour is embedded in sociocultural and contextual frameworks, all teaching should provide cross-cultural awareness of that complexity as well as of the internal variation within language. Therefore, the research explored the interplay of sociolinguistic factors in the teaching of English in Zimbabwe. The Mixed Methods design; a combination of the descriptive survey and the case study was adopted. The questionnaire, interview, observation and document analysis methods were used to collect both qualitative and quantitative data to assess the role of sociolinguistic factors in second language teaching pedagogy. A combination of convenient sampling and stratified random sampling was used to come up with a sample representative of the school categories and the gender of teachers in the 38 secondary schools in Gweru District. The data for the research was collected from a random sample of 50 teachers. The data analysis supported the need for a reconceptualisation of ESL teaching in Zimbabwe. Notably, language teaching tended to be exam-centric, unimaginative and not well linked to the needs of the learners in the communicative environment outside the school. This confirmed the initial observation that the secondary school graduates generally lacked sociolinguistic competence skills. The teachers were, however generally not motivated to include culture and sociolinguistics in their teaching. The research therefore recommended a revisit of the 7 | Page allowance for the interplay of sociolinguistic factors at all the planning stages of the ESL curriculum; the status, corpus and acquisition stages.
- Full Text:
- Date Issued: 2019
From ‘cleanliness is next to Godliness’ to ‘without perfect health, there is nothing’: discourses of healthy lifestyle in the construction of young adult identities in urban South Africa
- Authors: De Jong, Michelle
- Date: 2019
- Subjects: Health , Cleanliness , Social structure -- Health aspects , Health behavior , Social medicine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64940 , vital:28638
- Description: This research explores popular constructions of “healthiness” as individual lifestyle choices in the context of contemporary South African consumer culture, and how these constructions relate to formations of subjectivity. This is a qualitative study conducted within a social constructionist, theoretical framework. Data was collected using in-depth, semi structured interviews and are analysed using a Foucauldian inspired version of discourse analysis. A critical stance is taken towards the assumption in these discourses that their version of healthiness is always and unquestionably positive. Special attention is paid to the lifestyle and marketing media discourses appropriated in understandings of personal health through self-management, and of the optimization of health in the pursuit of well-being. The ways in which different discourses of healthiness facilitate the construction of specific identities are considered in order to untangle some of the problems created by the moralism underpinning popular consumer health discourse. How constructions of healthiness and aspirant healthy lifestyles support, and are supported by, the ideologies and practices of neoliberal capitalism are also explored. From this perspective, healthiness as lifestyle consumption choices can be seen as an ideological apparatus that produces the subjects necessary to reproduce the social order (Althusser, 2001), functioning not only positively amongst the social classes with the leisure and economic resources to pursue these options, but also negatively as victim-blaming of those who are excluded. The argument here is not that health is bad or that people should not be bothered with activities aimed at promoting good health, but that in a context where the concept of health is idealised as always positive and beneficial, the potentially harmful consequences of some of the health discourses we make use of may be occluded. This idealisation of health or ‘healthism’ may also function to divert attention away from some of the challenges to health that are not the direct result of personal behaviours and are unlikely to be remedied through individually focussed interventions, for example, inequality and inadequate access to basic resources. Six discourses which were used to construct understandings of health are analysed. These include Happiness, Freedom, Control, Care, Balance and Goodness. The ways in which these discourses played a role in constructing the kinds of subject positions which were made available to participants, and the possible implications this has, are explored in depth.
- Full Text:
- Date Issued: 2019
- Authors: De Jong, Michelle
- Date: 2019
- Subjects: Health , Cleanliness , Social structure -- Health aspects , Health behavior , Social medicine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64940 , vital:28638
- Description: This research explores popular constructions of “healthiness” as individual lifestyle choices in the context of contemporary South African consumer culture, and how these constructions relate to formations of subjectivity. This is a qualitative study conducted within a social constructionist, theoretical framework. Data was collected using in-depth, semi structured interviews and are analysed using a Foucauldian inspired version of discourse analysis. A critical stance is taken towards the assumption in these discourses that their version of healthiness is always and unquestionably positive. Special attention is paid to the lifestyle and marketing media discourses appropriated in understandings of personal health through self-management, and of the optimization of health in the pursuit of well-being. The ways in which different discourses of healthiness facilitate the construction of specific identities are considered in order to untangle some of the problems created by the moralism underpinning popular consumer health discourse. How constructions of healthiness and aspirant healthy lifestyles support, and are supported by, the ideologies and practices of neoliberal capitalism are also explored. From this perspective, healthiness as lifestyle consumption choices can be seen as an ideological apparatus that produces the subjects necessary to reproduce the social order (Althusser, 2001), functioning not only positively amongst the social classes with the leisure and economic resources to pursue these options, but also negatively as victim-blaming of those who are excluded. The argument here is not that health is bad or that people should not be bothered with activities aimed at promoting good health, but that in a context where the concept of health is idealised as always positive and beneficial, the potentially harmful consequences of some of the health discourses we make use of may be occluded. This idealisation of health or ‘healthism’ may also function to divert attention away from some of the challenges to health that are not the direct result of personal behaviours and are unlikely to be remedied through individually focussed interventions, for example, inequality and inadequate access to basic resources. Six discourses which were used to construct understandings of health are analysed. These include Happiness, Freedom, Control, Care, Balance and Goodness. The ways in which these discourses played a role in constructing the kinds of subject positions which were made available to participants, and the possible implications this has, are explored in depth.
- Full Text:
- Date Issued: 2019
Genetic characterisation of a range of geographically distinct Helicoverpa armigera nucleopolyhedrovirus (HearNPV) isolates and evaluation of biological activity against South African populations of the African bollworm, Helicoverpa armigera (Hu bner) (Lepidoptera: Noctuidae)
- Mtambanengwe, Kudzai Tapiwanashe Esau
- Authors: Mtambanengwe, Kudzai Tapiwanashe Esau
- Date: 2019
- Subjects: Helicoverpa armigera -- Biological control -- South Africa , Baculoviruses -- Genetics , Agricultural pests -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/97334 , vital:31426
- Description: The African bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a pest of economic and agricultural importance globally. It is a polyphagous pest that feeds on a wide range of host plants including economically important crops. The impact it has on agricultural systems makes its control a priority. The most common method of control is using chemical pesticides; however, continuous application of the pesticides has resulted in the development of resistance. The use of biological control has been investigated and established as an effective method of control as a standalone or part of an integrated pest management (IPM) system. The use of the baculovirus Helicoverpa armigera nucleopolyhedrovirus (HearNPV), has shown promise in the control of H. armigera. Commercial formulations based on the virus are available in many global markets. However, the identification of novel HearNPV isolates will aid in the control of H. armigera as well as provide alternative isolates that may have better virulence. Three new HearNPV isolates were purified and identified from three distinct geographical South African locations H. armigera cadavers and named HearNPV-Albany, HearNPV-KZN and HearNPV-Haygrove. The genomes of two of the HearNPV isolates, namely HearNPV-Albany and HearNPV-KZN were genetically characterised and compared to other geographically distinct HearNPV isolates. Virulence studies were performed comparing the new HearNPV isolates against established commercial HearNPV formulations, Helicovir™ and Helicovex® and other geographically distinct isolated HearNPV, HearNPV-G4 and HearNPV-SP1. Two laboratory colonies were established using H. armigera collected from South African fields in the Belmont Valley near Grahamstown labelled as Albany colony and a colony provided from Haygrove Eden farm near George labelled as Haygrove colony. Biological studies were carried out using the Albany H. armigera colony comparing the rate of development, survival and fertility on bell green peppers, cabbage leaves and on artificial diet. From the biological studies, it was recorded that development and survivorship was best on artificial diet. Regular quality control was required for the maintenance of the colony and continuous generations of healthy larvae were eventually established. Diseased cadavers with signs of baculovirus infection were collected after bioprospecting from the Kwa-Zulu Natal Province in South Africa and were labelled KZN isolate; Belmont Valley near Grahamstown and were labelled Albany isolate; and Haygrove Eden farm near George and were labelled Haygrove isolate for the study. A fourth isolate made up of a crude extract of occlusion bodies (OBs) first described by Whitlock was also analysed and labelled Whitlock isolate. Occlusion bodies were extracted, purified and morphologically identified from the KZN, Albany, Haygrove and Whitlock isolates using TEM. Genomic DNA, which was extracted from the purified OBs. Using PCR, the identity of the OBs as HearNPV was confirmed. Genomic analyses were performed on HearNPV-Albany and HearNPV-KZN through genetic characterisation and comparison with other geographically distinct HearNPV genomes to confirm novelty and establish potential genetic relationships between the isolates through evolutionary distances. Full genomic sequencing of the isolated HearNPV and comparison with other geographically distinct HearNPV isolates identified genomic differences that showed that the HearNPV isolates were novel. HearNPV-Albany and HearNPV-KZN were successfully sequenced and identified as novel isolates with unique fragment patterns and unique gene sequences through deletions or insertions when compared to other geographically distinct HearNPV. This raised the potential for differences in biological activity against H. armigera larvae when tested through biological assays. HearNPV-Whit genome assembly had low quality data which resulted in many gaps and failed assembly. The biological activity of HearNPV isolates from Spain, China, South Africa and two commercial formulations were studied against the laboratory established H. armigera South African colony. The LC50 values of the different South African HearNPV isolates were established to be between 7.7 × 101 OBs.ml-1 for the most effective and 3.2 × 102 OBs.ml-1 for the least effective. The Spanish and Chinese HearNPV isolates resulted in LC50 values of 2.0 × 102 OBs.ml-1 and 1.2 × 101 OBs.ml-1 respectively. The commercial formulations resulted in the least virulence observed with an LC50 of 5.84× 102 OBs.ml-1 and 9.0 × 102 OBs.ml-1 for Helicovex® and Helicovir™ respectively. In this study, novel South African HearNPV isolates were isolated and identified. Through characterisation and bioassays against South African H. armigera populations the HearNPV isolates were shown to have different virulence in comparison to geographically distinct isolates. From this research, there is potential for development of new H. armigera biopesticides based on the novel isolates after field trial testing.
- Full Text:
- Date Issued: 2019
- Authors: Mtambanengwe, Kudzai Tapiwanashe Esau
- Date: 2019
- Subjects: Helicoverpa armigera -- Biological control -- South Africa , Baculoviruses -- Genetics , Agricultural pests -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/97334 , vital:31426
- Description: The African bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a pest of economic and agricultural importance globally. It is a polyphagous pest that feeds on a wide range of host plants including economically important crops. The impact it has on agricultural systems makes its control a priority. The most common method of control is using chemical pesticides; however, continuous application of the pesticides has resulted in the development of resistance. The use of biological control has been investigated and established as an effective method of control as a standalone or part of an integrated pest management (IPM) system. The use of the baculovirus Helicoverpa armigera nucleopolyhedrovirus (HearNPV), has shown promise in the control of H. armigera. Commercial formulations based on the virus are available in many global markets. However, the identification of novel HearNPV isolates will aid in the control of H. armigera as well as provide alternative isolates that may have better virulence. Three new HearNPV isolates were purified and identified from three distinct geographical South African locations H. armigera cadavers and named HearNPV-Albany, HearNPV-KZN and HearNPV-Haygrove. The genomes of two of the HearNPV isolates, namely HearNPV-Albany and HearNPV-KZN were genetically characterised and compared to other geographically distinct HearNPV isolates. Virulence studies were performed comparing the new HearNPV isolates against established commercial HearNPV formulations, Helicovir™ and Helicovex® and other geographically distinct isolated HearNPV, HearNPV-G4 and HearNPV-SP1. Two laboratory colonies were established using H. armigera collected from South African fields in the Belmont Valley near Grahamstown labelled as Albany colony and a colony provided from Haygrove Eden farm near George labelled as Haygrove colony. Biological studies were carried out using the Albany H. armigera colony comparing the rate of development, survival and fertility on bell green peppers, cabbage leaves and on artificial diet. From the biological studies, it was recorded that development and survivorship was best on artificial diet. Regular quality control was required for the maintenance of the colony and continuous generations of healthy larvae were eventually established. Diseased cadavers with signs of baculovirus infection were collected after bioprospecting from the Kwa-Zulu Natal Province in South Africa and were labelled KZN isolate; Belmont Valley near Grahamstown and were labelled Albany isolate; and Haygrove Eden farm near George and were labelled Haygrove isolate for the study. A fourth isolate made up of a crude extract of occlusion bodies (OBs) first described by Whitlock was also analysed and labelled Whitlock isolate. Occlusion bodies were extracted, purified and morphologically identified from the KZN, Albany, Haygrove and Whitlock isolates using TEM. Genomic DNA, which was extracted from the purified OBs. Using PCR, the identity of the OBs as HearNPV was confirmed. Genomic analyses were performed on HearNPV-Albany and HearNPV-KZN through genetic characterisation and comparison with other geographically distinct HearNPV genomes to confirm novelty and establish potential genetic relationships between the isolates through evolutionary distances. Full genomic sequencing of the isolated HearNPV and comparison with other geographically distinct HearNPV isolates identified genomic differences that showed that the HearNPV isolates were novel. HearNPV-Albany and HearNPV-KZN were successfully sequenced and identified as novel isolates with unique fragment patterns and unique gene sequences through deletions or insertions when compared to other geographically distinct HearNPV. This raised the potential for differences in biological activity against H. armigera larvae when tested through biological assays. HearNPV-Whit genome assembly had low quality data which resulted in many gaps and failed assembly. The biological activity of HearNPV isolates from Spain, China, South Africa and two commercial formulations were studied against the laboratory established H. armigera South African colony. The LC50 values of the different South African HearNPV isolates were established to be between 7.7 × 101 OBs.ml-1 for the most effective and 3.2 × 102 OBs.ml-1 for the least effective. The Spanish and Chinese HearNPV isolates resulted in LC50 values of 2.0 × 102 OBs.ml-1 and 1.2 × 101 OBs.ml-1 respectively. The commercial formulations resulted in the least virulence observed with an LC50 of 5.84× 102 OBs.ml-1 and 9.0 × 102 OBs.ml-1 for Helicovex® and Helicovir™ respectively. In this study, novel South African HearNPV isolates were isolated and identified. Through characterisation and bioassays against South African H. armigera populations the HearNPV isolates were shown to have different virulence in comparison to geographically distinct isolates. From this research, there is potential for development of new H. armigera biopesticides based on the novel isolates after field trial testing.
- Full Text:
- Date Issued: 2019
Genetic characteristics of Human Immunodeficiency Virus-1, and deter-minants of late presentation for care and Diabetes mellitus amongst newly diagnosed Human Immunodeficiency Virus positive patients in the Eastern Cape, South Africa.
- Authors: Sogbanmu, Olufunso Oladipo
- Date: 2019
- Subjects: HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/${Handle} , vital:40495
- Description: Phylogenies may help to characterize transmission pairs, enhance contact tracing and outbreak investigations, track the origin and spread of epidemics over place and time, and to identify patterns of onward Human Immunodeficiency-Virus (HIV) transmission among risk groups. If the pattern and evolution of HIV drug resistance can be mapped, this may influence the development of guidelines in the clinical management of HIV especially with issues relating to prevalence of primary drug resistance and its impact on outcomes of present antiretroviral treatment (ART) regimen in use and the ability to trace and track the development of drug resistant strains. The roll-out of the test and treat Programme for newly diagnosed HIV infected pa-tient, seeks to identify HIV infected individuals early and to prevent morbidity and mortality associated with the late presentation for HIV care. The determination of the magnitude of ‘late presentation’ and or ‘presentation with advanced HIV disease’ can be used in very diverse settings and for many purposes. It provides a unified way to define the problem, thereby targeting appropriate interventions to prevent the detrimental outcomes associated with late presentation to care. The subtle relationship between HIV and diabetes mellitus (DM) may also help in formulating better preventive programs to aid the control of non-communicable diseases such as DM. This cross-sectional study includes a purposive selection of 335 HIV positive patients attending the voluntary counselling and Testing (VCT) and HIV Counselling and Testing (HCT) centres and outpatient departments at Cecilia Makiwane Hospital and the HCT sites at the Buffalo District municipality community health centres, Eastern Cape Province, South Africa. Late or delayed presentation of HIV infection was defined as CD4 cell count beneath 350 cells/μL and/or patients presenting with an AIDS-defining event at the first follow-up regardless of the CD4 cell count. Chapter 1 provides the general introduction had an overview of the introduction to the study, the statement of the research problem, hypothesis, the aim and the objectives. xx Chapter 2 looked in-depth at the HIV, case definition, the latest epidemiology of HIV, the HIV genome, the life cycle of HIV, its diagnosis, the classes of antiretroviral drugs, development of drug resistance. Chapter 3 highlighted the prevalence of Transmitted Drug Resistance (TDR) with focus on the protease gene. RNA was extracted from blood samples of 72 newly diagnosed HIV-1 patients attending some HIV testing and counselling clinics from August 2016 to July 2017. Protease fragments were amplified with specific primers by RT-PCR followed by nested PCR. The amplified products were sequenced using the ABI 360 sequencer, edited with Geneious version 9.1.5 and translated into amino acid with BioEdit software. Drug related resistance mutation (DRMs) analysis was performed on all the protease sequences in accordance with the 2009 WHO list of surveillance drug resistance mutations by submitting the edited sequences to Stanford HIV drug interpretation programme and the international AIDS society-USA guidelines for query of drug resistance associated mutations while phylogenetic analysis was performed using MEGA 6 to allocate all viral sequences into subtypes. In the study, a total of 52/72 (71.1%) reliable HIV-1 protease sequences were obtained in which subtyping and drug resistance mutations were performed. Two (3.8%) major Protease resistance associated mutation (V82A/L and L90M) were observed while another polymorphism like L10F, T74S, Q58E, L10I/V and M46V were also identified. Phylogenetic analyses delineated all the sequences as HIV-1 subtype C. Chapter 4 describes the prevalence and the determinants of late presentation amongst newly diagnosed HIV positive individuals in the Eastern Cape. It indicates the extent of the prevalence of patients presenting to care and at what HIV stage they were assessing health care services since the inception of the ‘test and treat’ strategy. It is a cross-sectional study where a total of 335 newly diagnosed patients were recruited consecutively be-tween August 2016 and July 2017. Late presenter for HIV care was defined in accordance with the European Late Presenter Consensus working group as a patient who reports for care when the CD4 count is below 350 cells/μL and/or when there is an established Aids- xxi defining clinical condition, irrespective of CD4 count. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of late HIV diagnosis. The study showed that 60% of patients were late presenters, with 35% presenting with advanced disease. The major determinants identified were being male and low level of education. This led to recommendations directed at ensuring programmes that targets men in identifying their HIV status and assess care at early stage to prevents the morbidity and mortality associated with delayed presentation. Also, it was recommended that effort should be made to improve access to education and also include HIV related topics into the educational curriculum. Chapter 5 aimed to describe the prevalence and determinants of DM amongst newly diagnosed HIV positive individuals. This is a cross-sectional study which recruited 335 patients between August 2016 and September 2017. Definition for diabetes mellitus was made based on the SEDMSA 2015 guideline of HBA1C of above 6.5%. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of abnormal glycated haemoglobin. Findings showed the prevalence of DM at about 6% amongst newly diagnosed HIV positive individuals. This is similar to findings in other study within the country, but a bit lower than what was obtained in the developed countries. The role of older age (above 40 years) as predisposing factor to development of diabetes in newly diagnosed HIV positive individual was well noted and taken. This ensures that screening for DM should be targeted at elderly HIV positive individuals. The grey area of the appropriate mode of diagnostic test to use to diagnose HIV is still debatable, however, a combination of HBA1c and fasting blood sugar (FBS) may improve the diagnosis of DM in this population group. In chapter 6, the general conclusions, recommendations and future perspectives of the study are reflected.
- Full Text:
- Date Issued: 2019
- Authors: Sogbanmu, Olufunso Oladipo
- Date: 2019
- Subjects: HIV infections
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/${Handle} , vital:40495
- Description: Phylogenies may help to characterize transmission pairs, enhance contact tracing and outbreak investigations, track the origin and spread of epidemics over place and time, and to identify patterns of onward Human Immunodeficiency-Virus (HIV) transmission among risk groups. If the pattern and evolution of HIV drug resistance can be mapped, this may influence the development of guidelines in the clinical management of HIV especially with issues relating to prevalence of primary drug resistance and its impact on outcomes of present antiretroviral treatment (ART) regimen in use and the ability to trace and track the development of drug resistant strains. The roll-out of the test and treat Programme for newly diagnosed HIV infected pa-tient, seeks to identify HIV infected individuals early and to prevent morbidity and mortality associated with the late presentation for HIV care. The determination of the magnitude of ‘late presentation’ and or ‘presentation with advanced HIV disease’ can be used in very diverse settings and for many purposes. It provides a unified way to define the problem, thereby targeting appropriate interventions to prevent the detrimental outcomes associated with late presentation to care. The subtle relationship between HIV and diabetes mellitus (DM) may also help in formulating better preventive programs to aid the control of non-communicable diseases such as DM. This cross-sectional study includes a purposive selection of 335 HIV positive patients attending the voluntary counselling and Testing (VCT) and HIV Counselling and Testing (HCT) centres and outpatient departments at Cecilia Makiwane Hospital and the HCT sites at the Buffalo District municipality community health centres, Eastern Cape Province, South Africa. Late or delayed presentation of HIV infection was defined as CD4 cell count beneath 350 cells/μL and/or patients presenting with an AIDS-defining event at the first follow-up regardless of the CD4 cell count. Chapter 1 provides the general introduction had an overview of the introduction to the study, the statement of the research problem, hypothesis, the aim and the objectives. xx Chapter 2 looked in-depth at the HIV, case definition, the latest epidemiology of HIV, the HIV genome, the life cycle of HIV, its diagnosis, the classes of antiretroviral drugs, development of drug resistance. Chapter 3 highlighted the prevalence of Transmitted Drug Resistance (TDR) with focus on the protease gene. RNA was extracted from blood samples of 72 newly diagnosed HIV-1 patients attending some HIV testing and counselling clinics from August 2016 to July 2017. Protease fragments were amplified with specific primers by RT-PCR followed by nested PCR. The amplified products were sequenced using the ABI 360 sequencer, edited with Geneious version 9.1.5 and translated into amino acid with BioEdit software. Drug related resistance mutation (DRMs) analysis was performed on all the protease sequences in accordance with the 2009 WHO list of surveillance drug resistance mutations by submitting the edited sequences to Stanford HIV drug interpretation programme and the international AIDS society-USA guidelines for query of drug resistance associated mutations while phylogenetic analysis was performed using MEGA 6 to allocate all viral sequences into subtypes. In the study, a total of 52/72 (71.1%) reliable HIV-1 protease sequences were obtained in which subtyping and drug resistance mutations were performed. Two (3.8%) major Protease resistance associated mutation (V82A/L and L90M) were observed while another polymorphism like L10F, T74S, Q58E, L10I/V and M46V were also identified. Phylogenetic analyses delineated all the sequences as HIV-1 subtype C. Chapter 4 describes the prevalence and the determinants of late presentation amongst newly diagnosed HIV positive individuals in the Eastern Cape. It indicates the extent of the prevalence of patients presenting to care and at what HIV stage they were assessing health care services since the inception of the ‘test and treat’ strategy. It is a cross-sectional study where a total of 335 newly diagnosed patients were recruited consecutively be-tween August 2016 and July 2017. Late presenter for HIV care was defined in accordance with the European Late Presenter Consensus working group as a patient who reports for care when the CD4 count is below 350 cells/μL and/or when there is an established Aids- xxi defining clinical condition, irrespective of CD4 count. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of late HIV diagnosis. The study showed that 60% of patients were late presenters, with 35% presenting with advanced disease. The major determinants identified were being male and low level of education. This led to recommendations directed at ensuring programmes that targets men in identifying their HIV status and assess care at early stage to prevents the morbidity and mortality associated with delayed presentation. Also, it was recommended that effort should be made to improve access to education and also include HIV related topics into the educational curriculum. Chapter 5 aimed to describe the prevalence and determinants of DM amongst newly diagnosed HIV positive individuals. This is a cross-sectional study which recruited 335 patients between August 2016 and September 2017. Definition for diabetes mellitus was made based on the SEDMSA 2015 guideline of HBA1C of above 6.5%. Adjusted and unadjusted logistic regression analysis was used to examine the determinants of abnormal glycated haemoglobin. Findings showed the prevalence of DM at about 6% amongst newly diagnosed HIV positive individuals. This is similar to findings in other study within the country, but a bit lower than what was obtained in the developed countries. The role of older age (above 40 years) as predisposing factor to development of diabetes in newly diagnosed HIV positive individual was well noted and taken. This ensures that screening for DM should be targeted at elderly HIV positive individuals. The grey area of the appropriate mode of diagnostic test to use to diagnose HIV is still debatable, however, a combination of HBA1c and fasting blood sugar (FBS) may improve the diagnosis of DM in this population group. In chapter 6, the general conclusions, recommendations and future perspectives of the study are reflected.
- Full Text:
- Date Issued: 2019
Genetic diversity, resistance profile of hiv and risk assessment of mother-to-child transmission in pregnant women on antiretroviral therapy in the Eastern Cape, South Africa
- Authors: Adeniyi, Oladele Vincent
- Date: 2019
- Subjects: Antiretroviral agents , HIV infections -- Treatment -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15120 , vital:40183
- Description: Despite the initiation of life-long ART in HIV-infected pregnant women, the rate and determinants of infant HIV transmission are not known, especially in the poor resource settings of the Eastern Cape, South Africa. Maternal anti-retroviral therapy (ART) is crucial for elimination of mother-to-child transmission (MTCT) of HIV. However, the inevitable risks of emergence of HIV drug resistance poses significant threat to achieving this goal of HIV-free generation and keeping mothers alive. Also, it is unclear if women with high viral load at delivery have acquired clinically relevant mutations, which could confer resistance to the ART, thus, further increasing the risks of motherto-child transmission of HIV-drug resistance strains. In addition to the gaps identified in the prevention of mother-to-child transmission (PMTCT) context, the understanding of regional epidemics is crucial to the broader epidemiological profiling of HIV infections in the country. Despite the rapid influx of foreign nationals to South African and Eastern Cape Province, there has not been any molecular epidemiological studies profiling the HIV diversity in the Eastern Cape.
- Full Text:
- Date Issued: 2019
- Authors: Adeniyi, Oladele Vincent
- Date: 2019
- Subjects: Antiretroviral agents , HIV infections -- Treatment -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15120 , vital:40183
- Description: Despite the initiation of life-long ART in HIV-infected pregnant women, the rate and determinants of infant HIV transmission are not known, especially in the poor resource settings of the Eastern Cape, South Africa. Maternal anti-retroviral therapy (ART) is crucial for elimination of mother-to-child transmission (MTCT) of HIV. However, the inevitable risks of emergence of HIV drug resistance poses significant threat to achieving this goal of HIV-free generation and keeping mothers alive. Also, it is unclear if women with high viral load at delivery have acquired clinically relevant mutations, which could confer resistance to the ART, thus, further increasing the risks of motherto-child transmission of HIV-drug resistance strains. In addition to the gaps identified in the prevention of mother-to-child transmission (PMTCT) context, the understanding of regional epidemics is crucial to the broader epidemiological profiling of HIV infections in the country. Despite the rapid influx of foreign nationals to South African and Eastern Cape Province, there has not been any molecular epidemiological studies profiling the HIV diversity in the Eastern Cape.
- Full Text:
- Date Issued: 2019