Information needs and information-seeking behaviour of practising medical doctors at Katutura and Windhoek central state hospitals in Namibia
- Authors: Matsveru, David
- Date: 2020
- Subjects: Information behavior Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17976 , vital:42000
- Description: This study investigated the information needs and information-seeking behaviour of practising medical doctors at Katutura and Windhoek Central hospitals in Namibia. Anchored on Wilson’s (1996) model of information-seeking behaviour, the purpose of the study was to establish the information required by practising medical doctors to carry out their work, how they seek information, the information sources and resources they use, and the factors that affect them as they do so. Understanding users’ information needs and the way information is disseminated in hospitals is necessary in developing an effective information provision system and ensuring the quality of information services in the hospitals. A mixed-methods research approach was used to meet the objectives of the study. Questionnaires were administered on 140 practising medical doctors at Katutura and Windhoek Central state hospitals, while fifteen doctors were interviewed telephonically, using a semi-structured interview guide. IBM SPSS (Version 25) was used to analyse quantitative data from the questionnaires, while content analysis was used to analyse qualitative data from the interviews. The findings of this research are that practising medical doctors need information mainly for improving clinical decision-making, keeping up-to-date, improving professional knowledge, and continuing education. The study also revealed that medical doctors use a variety of information sources and resources. However, the degree to which information sources are xiii used depends on the clinical context (outpatients, wards and casualty/emergency). Some contextual factors (organisational context, socio-cultural context, and information sources) can either support or hinder doctors in seeking the information they need. The patient is one of the primary information sources for medical doctors. However, language problems are a significant challenge in communicating with patients or patients’ relatives. Lack of patients’ understanding of medical terms and unavailability of properly run libraries in hospitals are some of the factors that affect doctors’ information-seeking behaviour. Participants recommended health education for patients, training of medical doctors on the use of the Internet and ICT, provision of properly run hospital libraries, and improved communication with other international hospitals as some of the ways to improve health information sources and services. Three related models were drawn from the study’s findings, based on Wilson’s (1996) model and literature, namely, the doctors’ decision-making model (DDmM), the clinical context information sources model (CCISM), and the model of information needs and information-seeking behaviour of medical doctors (MINISBMD). The thesis concludes with practical recommendations to enhance the provision of information at Katutura and Windhoek Central hospitals and suggestions for further research.
- Full Text:
- Date Issued: 2020
- Authors: Matsveru, David
- Date: 2020
- Subjects: Information behavior Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17976 , vital:42000
- Description: This study investigated the information needs and information-seeking behaviour of practising medical doctors at Katutura and Windhoek Central hospitals in Namibia. Anchored on Wilson’s (1996) model of information-seeking behaviour, the purpose of the study was to establish the information required by practising medical doctors to carry out their work, how they seek information, the information sources and resources they use, and the factors that affect them as they do so. Understanding users’ information needs and the way information is disseminated in hospitals is necessary in developing an effective information provision system and ensuring the quality of information services in the hospitals. A mixed-methods research approach was used to meet the objectives of the study. Questionnaires were administered on 140 practising medical doctors at Katutura and Windhoek Central state hospitals, while fifteen doctors were interviewed telephonically, using a semi-structured interview guide. IBM SPSS (Version 25) was used to analyse quantitative data from the questionnaires, while content analysis was used to analyse qualitative data from the interviews. The findings of this research are that practising medical doctors need information mainly for improving clinical decision-making, keeping up-to-date, improving professional knowledge, and continuing education. The study also revealed that medical doctors use a variety of information sources and resources. However, the degree to which information sources are xiii used depends on the clinical context (outpatients, wards and casualty/emergency). Some contextual factors (organisational context, socio-cultural context, and information sources) can either support or hinder doctors in seeking the information they need. The patient is one of the primary information sources for medical doctors. However, language problems are a significant challenge in communicating with patients or patients’ relatives. Lack of patients’ understanding of medical terms and unavailability of properly run libraries in hospitals are some of the factors that affect doctors’ information-seeking behaviour. Participants recommended health education for patients, training of medical doctors on the use of the Internet and ICT, provision of properly run hospital libraries, and improved communication with other international hospitals as some of the ways to improve health information sources and services. Three related models were drawn from the study’s findings, based on Wilson’s (1996) model and literature, namely, the doctors’ decision-making model (DDmM), the clinical context information sources model (CCISM), and the model of information needs and information-seeking behaviour of medical doctors (MINISBMD). The thesis concludes with practical recommendations to enhance the provision of information at Katutura and Windhoek Central hospitals and suggestions for further research.
- Full Text:
- Date Issued: 2020
Integrating quality management principles into policies and procedures for water and sanitation provision in the Cape Town Metro
- Authors: Madliwa, Nokhanyo
- Date: 2020
- Subjects: Total quality management local government Quality assurance
- Language: English
- Type: Thesis , Doctoral , DPA
- Identifier: http://hdl.handle.net/10353/18882 , vital:42995
- Description: The study aims to find a way of improving water and sanitation services through the standardisation of policies and procedures in Reticulation, Waste Water and Bulk Water. It further aims to develop and test an IQM-based model that improves policy and procedure standardisation for the provision of quality water and sanitation services at municipality level. The researcher regards effective IQMS as one of the possible mechanisms that can contribute to the improvement of standardised policies and procedures in quality water and sanitation provision. This study examined the effects of IQM on the standardisation of policies and procedures for the provision of quality water and sanitation services in the Utility Department of the Cape Town Metro, especially in Reticulation, Waste Water and Bulk Water. The study saw a possible link between the effectiveness of IQM and the effective provisioning of quality water and sanitation. The mixed method approach was used. Quantitative and qualitative methods were both used in order to support each other during data analysis. Furthermore, the mixed method was adopted to provide an interpretative and analytical balance towards a clearer understanding of the phenomena under study. The quantitative phase was completed first, followed by the qualitative phase to explain the results even further. For the quantitative method, survey data was gathered. The quantitative method was used for historical numerical data purposes when explaining the survey results. Survey data was analysed using statistical analysis. The qualitative method utilised interviews, providing clarity and thick descriptions of the findings, where quantitative methods did not. This research found that the three branches of the Utility Department in the Cape Town Metro under study did not fully comply with the IQMS as shown by the results of the hypothesis testing. In other words, there is partial compliance with ISO 140001, ISO 9001 & OHSAS 18001 in relation to the standardisation of policy and procedure design and development (DD), implementation (IP), examination (EP), review (RP) and assessment (AP). This means that components of IQMS were not fully applied to the standardisation of policies and procedures for the provision of water and sanitation services. The partial standardisation of policy and procedure vi design and development accounted for the lack of the following: Firstly, improvement in the management of infrastructure, secondly in monitoring and evaluation for quality water and sanitation services. The partial standardisation of policy and procedure implementation accounted for the lack of improvement in the corrective measures, technical knowledge and public health knowledge for quality water and sanitation services. The partial standardisation of policy and procedure examination accounted for the lack of improvement in the corrective measures, management of infrastructure; and monitoring and evaluation for quality water and sanitation services. The partial standardisation of policy and procedure review accounted for the lack of improvement in the corrective measures, management of infrastructure; monitoring and evaluation, technical knowledge and public health knowledge for quality water and sanitation services. Last but not least, the partial standardisation of policy and procedure assessment accounted for the lack of improvement in the corrective measures, and technical knowledge for quality water and sanitation services
- Full Text:
- Date Issued: 2020
- Authors: Madliwa, Nokhanyo
- Date: 2020
- Subjects: Total quality management local government Quality assurance
- Language: English
- Type: Thesis , Doctoral , DPA
- Identifier: http://hdl.handle.net/10353/18882 , vital:42995
- Description: The study aims to find a way of improving water and sanitation services through the standardisation of policies and procedures in Reticulation, Waste Water and Bulk Water. It further aims to develop and test an IQM-based model that improves policy and procedure standardisation for the provision of quality water and sanitation services at municipality level. The researcher regards effective IQMS as one of the possible mechanisms that can contribute to the improvement of standardised policies and procedures in quality water and sanitation provision. This study examined the effects of IQM on the standardisation of policies and procedures for the provision of quality water and sanitation services in the Utility Department of the Cape Town Metro, especially in Reticulation, Waste Water and Bulk Water. The study saw a possible link between the effectiveness of IQM and the effective provisioning of quality water and sanitation. The mixed method approach was used. Quantitative and qualitative methods were both used in order to support each other during data analysis. Furthermore, the mixed method was adopted to provide an interpretative and analytical balance towards a clearer understanding of the phenomena under study. The quantitative phase was completed first, followed by the qualitative phase to explain the results even further. For the quantitative method, survey data was gathered. The quantitative method was used for historical numerical data purposes when explaining the survey results. Survey data was analysed using statistical analysis. The qualitative method utilised interviews, providing clarity and thick descriptions of the findings, where quantitative methods did not. This research found that the three branches of the Utility Department in the Cape Town Metro under study did not fully comply with the IQMS as shown by the results of the hypothesis testing. In other words, there is partial compliance with ISO 140001, ISO 9001 & OHSAS 18001 in relation to the standardisation of policy and procedure design and development (DD), implementation (IP), examination (EP), review (RP) and assessment (AP). This means that components of IQMS were not fully applied to the standardisation of policies and procedures for the provision of water and sanitation services. The partial standardisation of policy and procedure vi design and development accounted for the lack of the following: Firstly, improvement in the management of infrastructure, secondly in monitoring and evaluation for quality water and sanitation services. The partial standardisation of policy and procedure implementation accounted for the lack of improvement in the corrective measures, technical knowledge and public health knowledge for quality water and sanitation services. The partial standardisation of policy and procedure examination accounted for the lack of improvement in the corrective measures, management of infrastructure; and monitoring and evaluation for quality water and sanitation services. The partial standardisation of policy and procedure review accounted for the lack of improvement in the corrective measures, management of infrastructure; monitoring and evaluation, technical knowledge and public health knowledge for quality water and sanitation services. Last but not least, the partial standardisation of policy and procedure assessment accounted for the lack of improvement in the corrective measures, and technical knowledge for quality water and sanitation services
- Full Text:
- Date Issued: 2020
Integrating sustainability dimensions into construction labour productivity determinants in Zimbabwe
- Authors: Moyo, Tirivavi
- Date: 2020
- Subjects: Construction industry -- Labor productivity -- Zimbabwe , Construction workers -- Zimbabwe Construction industry -- Employees -- Zimbabwe Construction industry -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46207 , vital:39514
- Description: Low construction labour productivity and inadequate welfare of construction workers is a compound challenge in Zimbabwe. This challenge is due to shortcomings situated in the Decent Work Agenda. Whilst a plethora of contributory factors exists, those that affect the Zimbabwean construction industry were identified for interrogation. Therefore, the study aimed to improve and sustain construction labour productivity in Zimbabwe through fulfilling significant decent work substantive elements, in consideration of demographic variables of stakeholders. A cross-sectional survey research strategy was utilised with quantitative data being collected from selected respondents through the use of questionnaires. The population for the study consisted of randomly selected construction companies registered with the Construction Industry Federation of Zimbabwe and based in Harare, Bulawayo and Shurugwi where site managers’/project managers’ participated. Construction skilled and semi-skilled workers on thirteen (13) construction sites, situated within the same study area, participated in the study. Educators from technical and vocational training institutions and respondents from relevant regulatory bodies were also selected to participate in the study. Quantitative data analysis methods which included Pearson chi-squared tests, Mann-Whitney U tests; Kruskal-Wallis tests, Pearson bivariate correlation method and Regression analysis were utilised. Demographic variables (age, gender, designation, educational levels and experience) were utilised to determine the existence of statistically significant differences in respondents’ perceptions. Construction companies are encouraged to implement corporate social responsibility strategies through equipping workers of different educational levels with knowledge and skills that can be transferred to and benefit themselves and their communities. Adequately trained construction workers best serve their communities through improving their livelihoods, improved safety and health consciousness and quality workmanship. People centred management aspects were found to be fundamental within construction sites as they promote the welfare of workers and should precede any productivity improvement drives. Technical and vocational training institutions need to inculcate sustainability learning objectives within their curricula if any meaning strides in enhancing welfare and productivity of workers is to be achieved. Also, establishing structured on-the-job training that incorporates sustainability learning objectives to achieve workers’ safety on sites is essential. There was a consensus that working conditions must ensure the welfare of workers first before any productivity gains can be realised. Provision of acceptable decent working conditions for different designations and educational levels was encouraged. A comprehensive model was developed for sustaining construction labour productivity that included statistically significant regression models and derived statistically significant demographics from construction labour productivity determinants under study. Validation of the regression models was undertaken through cross-validation and comparison with existing theory. Tenable labour productivity performance measurement and reporting must be inclusive of decent work accomplishments. Short-term interventions that include awareness campaigns and provision of adequate working conditions are required for project-based resolutions whilst, long-term interventions are required where structural reforms within the training of skilled, semi-skilled workers and managers are required, for continuous improvement.
- Full Text:
- Date Issued: 2020
Integrating sustainability dimensions into construction labour productivity determinants in Zimbabwe
- Authors: Moyo, Tirivavi
- Date: 2020
- Subjects: Construction industry -- Labor productivity -- Zimbabwe , Construction workers -- Zimbabwe Construction industry -- Employees -- Zimbabwe Construction industry -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46207 , vital:39514
- Description: Low construction labour productivity and inadequate welfare of construction workers is a compound challenge in Zimbabwe. This challenge is due to shortcomings situated in the Decent Work Agenda. Whilst a plethora of contributory factors exists, those that affect the Zimbabwean construction industry were identified for interrogation. Therefore, the study aimed to improve and sustain construction labour productivity in Zimbabwe through fulfilling significant decent work substantive elements, in consideration of demographic variables of stakeholders. A cross-sectional survey research strategy was utilised with quantitative data being collected from selected respondents through the use of questionnaires. The population for the study consisted of randomly selected construction companies registered with the Construction Industry Federation of Zimbabwe and based in Harare, Bulawayo and Shurugwi where site managers’/project managers’ participated. Construction skilled and semi-skilled workers on thirteen (13) construction sites, situated within the same study area, participated in the study. Educators from technical and vocational training institutions and respondents from relevant regulatory bodies were also selected to participate in the study. Quantitative data analysis methods which included Pearson chi-squared tests, Mann-Whitney U tests; Kruskal-Wallis tests, Pearson bivariate correlation method and Regression analysis were utilised. Demographic variables (age, gender, designation, educational levels and experience) were utilised to determine the existence of statistically significant differences in respondents’ perceptions. Construction companies are encouraged to implement corporate social responsibility strategies through equipping workers of different educational levels with knowledge and skills that can be transferred to and benefit themselves and their communities. Adequately trained construction workers best serve their communities through improving their livelihoods, improved safety and health consciousness and quality workmanship. People centred management aspects were found to be fundamental within construction sites as they promote the welfare of workers and should precede any productivity improvement drives. Technical and vocational training institutions need to inculcate sustainability learning objectives within their curricula if any meaning strides in enhancing welfare and productivity of workers is to be achieved. Also, establishing structured on-the-job training that incorporates sustainability learning objectives to achieve workers’ safety on sites is essential. There was a consensus that working conditions must ensure the welfare of workers first before any productivity gains can be realised. Provision of acceptable decent working conditions for different designations and educational levels was encouraged. A comprehensive model was developed for sustaining construction labour productivity that included statistically significant regression models and derived statistically significant demographics from construction labour productivity determinants under study. Validation of the regression models was undertaken through cross-validation and comparison with existing theory. Tenable labour productivity performance measurement and reporting must be inclusive of decent work accomplishments. Short-term interventions that include awareness campaigns and provision of adequate working conditions are required for project-based resolutions whilst, long-term interventions are required where structural reforms within the training of skilled, semi-skilled workers and managers are required, for continuous improvement.
- Full Text:
- Date Issued: 2020
Invasion status and impact potential of Florida bass Micropterus floridanus in South Africa
- Authors: Khosa, Dumisani
- Date: 2020
- Subjects: Micropterus floridanus , Florida largemouth bass -- South Africa , Black bass -- South Africa , Micropterus floridanus -- South Africa -- Habitat , Florida largemouth bass -- South Africa -- Habitat , Black bass -- South Africa -- Habitat , Introduced fishes -- Environmental aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165733 , vital:41276
- Description: In South Africa, the introduction of alien fishes was largely driven by the development of recreational fishing opportunities. Government-backed programmes resulted in the introduction of four Black Bass species: Micropterus salmoides, Micropterus dolomieu, Micropterus punctulatus and Micropterus floridanus. These species are regarded as the primary threat to native biota and there is an urgent need to assess their spread and impacts. This thesis focuses on: assessing the current distribution of all four Black Basses; using genetic techniques to establish the extent of hybridisation between M. salmoides and M. floridanus, and using functional responses to assess the impact potential of M. salmoides and M. floridanus under the context dependence of temperatures and habitat complexity. Maximum entropy modelling of habitat suitability for Black Bass highlighted that M. salmoides had broad climatic suitability across South Africa, while suitability for M. dolomieu and M. punctulatus was restricted to the Cape Fold Ecoregion. An extensive area-based invasion debt was observed for all Micropterus spp. To better understand the dynamics of hybridisation between M. salmoides and M. floridanus, 38 species-diagnostic single nucleotide polymorphism was used to screen Black Bass populations from the Breede River and Kowie River catchments. Micropterus salmoides alleles were more prevalent than M. floridanus in both the Breede River catchments (69.1% and 30.9%, respectively) and Kowie River catchments (63.3% and 36.7%, respectively). However, isolated populations found in dams (reservoirs) remained free from hybridisation. To compare resource utilisation (i.e. per capita effects) between M. salmoides and M. floridanus, two experimental chapters were designed. Chapter 4 focuses on how temperature mitigates per capita effects between the two Black Basses. There was a significant decrease in per capita effects for M. salmoides with increasing temperatures, while the converse was true for M. floridanus. Chapter 5 gives an account of the influence of habitat complexity on per capita effects. The results showed that habitat complexity did mitigate per capita effects, specifically on M. floridanus, which showed a significant drop in per capita effects; however, no significant difference was recorded for M. salmoides. In the two experimental chapters, M. floridanus exhibited a superior per capita effect compared to M. salmoides, implying higher predation impact on native biota.
- Full Text:
- Date Issued: 2020
- Authors: Khosa, Dumisani
- Date: 2020
- Subjects: Micropterus floridanus , Florida largemouth bass -- South Africa , Black bass -- South Africa , Micropterus floridanus -- South Africa -- Habitat , Florida largemouth bass -- South Africa -- Habitat , Black bass -- South Africa -- Habitat , Introduced fishes -- Environmental aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165733 , vital:41276
- Description: In South Africa, the introduction of alien fishes was largely driven by the development of recreational fishing opportunities. Government-backed programmes resulted in the introduction of four Black Bass species: Micropterus salmoides, Micropterus dolomieu, Micropterus punctulatus and Micropterus floridanus. These species are regarded as the primary threat to native biota and there is an urgent need to assess their spread and impacts. This thesis focuses on: assessing the current distribution of all four Black Basses; using genetic techniques to establish the extent of hybridisation between M. salmoides and M. floridanus, and using functional responses to assess the impact potential of M. salmoides and M. floridanus under the context dependence of temperatures and habitat complexity. Maximum entropy modelling of habitat suitability for Black Bass highlighted that M. salmoides had broad climatic suitability across South Africa, while suitability for M. dolomieu and M. punctulatus was restricted to the Cape Fold Ecoregion. An extensive area-based invasion debt was observed for all Micropterus spp. To better understand the dynamics of hybridisation between M. salmoides and M. floridanus, 38 species-diagnostic single nucleotide polymorphism was used to screen Black Bass populations from the Breede River and Kowie River catchments. Micropterus salmoides alleles were more prevalent than M. floridanus in both the Breede River catchments (69.1% and 30.9%, respectively) and Kowie River catchments (63.3% and 36.7%, respectively). However, isolated populations found in dams (reservoirs) remained free from hybridisation. To compare resource utilisation (i.e. per capita effects) between M. salmoides and M. floridanus, two experimental chapters were designed. Chapter 4 focuses on how temperature mitigates per capita effects between the two Black Basses. There was a significant decrease in per capita effects for M. salmoides with increasing temperatures, while the converse was true for M. floridanus. Chapter 5 gives an account of the influence of habitat complexity on per capita effects. The results showed that habitat complexity did mitigate per capita effects, specifically on M. floridanus, which showed a significant drop in per capita effects; however, no significant difference was recorded for M. salmoides. In the two experimental chapters, M. floridanus exhibited a superior per capita effect compared to M. salmoides, implying higher predation impact on native biota.
- Full Text:
- Date Issued: 2020
Investigating the fitness of sea turtles nesting in South Africa
- Le Gouvello du Timat, Diane Z M
- Authors: Le Gouvello du Timat, Diane Z M
- Date: 2020
- Subjects: Sea turtles -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48445 , vital:40877
- Description: The South African rookeries of the South Western Indian Ocean (SWIO) loggerhead and leatherback regional management units have been continuously monitored for more than 5 decades, representing one of the longest-running sea turtle beach protection and monitoring programmes in the world. Although such conservation has been successful in protecting adults on land when they come to nest, it might not be enough to ensure population recovery if survival is not ensured across all life stages. Sea turtles are particularly vulnerable to direct threats and changing environmental conditions because they are long-lived, slow maturing, and have low survival rates at early life stages, making them conservation-dependent. These characteristics also render them difficult to conserve as a consequence of their wide geographic distributions, spanning multiple jurisdictions and legislative systems with different conservation targets, and a complex life cycle with changes in habitats and diets at different life stages. Sea turtle populations have been severely depleted as a result of historical over-exploitation and current threats including fisheries bycatch, direct harvest, habitat loss, pollution and pathogens, and climate change. In many cases however, population declines have been reversed by a variety of effective conservation measures such as beach protection programs, and marine protected areas, enabling successful population recovery around the world. Despite protection and apparent increase in abundance, indirect pressures can still affect turtle populations. Therefore, it is fundamental to evaluate the effectiveness of conservation measures (using fitness traits such as female and hatchling sizes) and examine underlying trends. The aim of this thesis was thus to evaluate the fitness of loggerhead and leatherback sea turtles nesting in South Africa. Long-term female size trends over time were evaluated and the populations were split between first-time nesters and experienced nesters. As sea turtle reproductive output (clutch size only) is correlated with female size and evidence is showing that in some populations individual female size is decreasing, the effects of maternal body size on reproductive output and hatchling fitness were investigated for both species. Crawling and swimming speeds were used as proxies of hatchling fitness, because these two traits positively influence their survival. An oceanic model was further used in combination with a particle tracking framework to estimate, for the first time, post-hatchling dispersal of loggerhead and leatherback turtles in the SWIO. I investigated whether the trend in female size for loggerhead turtles nesting in South Africa is a result of their foraging strategy to determine if there is a foraging dichotomy (neritic and oceanic). Despite an apparent increasing population, a significant 3.7 and 3.6 cm decrease in the size of both recruit and remingrant female loggerhead turtles, but a stable mean size of leatherbacks for both age groups was observed. I hypothesise that these contradictory effects are attributable to the very distinct foraging ecologies of the two turtle species and speculate that these variations in carapace length may be driven by environmental change. The reproductive strategy of both loggerhead and leatherback turtles nesting in South Africa supports the optimal egg size theory with larger turtles producing larger clutches but not larger eggs. Egg size was thus constant irrespective of maternal length. Hatchlings with longer carapaces and flippers had higher swimming speed, suggesting that larger hatchlings are fitter (potentially higher survival) than smaller ones by spending less time in high predation risk areas (i.e. beach and nearshore). The model revealed that dispersal trajectories of both loggerhead and leatherback sea turtle hatchlings were very similar and simulations indicated that initial active swimming (frenzy) as well as variability in oceanic conditions strongly influenced dispersal of virtual hatchlings. The trends observed in this study emphasize the importance of long-term monitoring, examining not only abundance but also individual size, to understand population dynamics, support recovery planning and prioritize future conservation practices. Furthermore, the findings of this study have important implications for overall population growth if smaller hatchlings of lower fitness are produced as a result of climate change and thus have decreased dispersal abilities and lower likelihood of survival.
- Full Text:
- Date Issued: 2020
- Authors: Le Gouvello du Timat, Diane Z M
- Date: 2020
- Subjects: Sea turtles -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48445 , vital:40877
- Description: The South African rookeries of the South Western Indian Ocean (SWIO) loggerhead and leatherback regional management units have been continuously monitored for more than 5 decades, representing one of the longest-running sea turtle beach protection and monitoring programmes in the world. Although such conservation has been successful in protecting adults on land when they come to nest, it might not be enough to ensure population recovery if survival is not ensured across all life stages. Sea turtles are particularly vulnerable to direct threats and changing environmental conditions because they are long-lived, slow maturing, and have low survival rates at early life stages, making them conservation-dependent. These characteristics also render them difficult to conserve as a consequence of their wide geographic distributions, spanning multiple jurisdictions and legislative systems with different conservation targets, and a complex life cycle with changes in habitats and diets at different life stages. Sea turtle populations have been severely depleted as a result of historical over-exploitation and current threats including fisheries bycatch, direct harvest, habitat loss, pollution and pathogens, and climate change. In many cases however, population declines have been reversed by a variety of effective conservation measures such as beach protection programs, and marine protected areas, enabling successful population recovery around the world. Despite protection and apparent increase in abundance, indirect pressures can still affect turtle populations. Therefore, it is fundamental to evaluate the effectiveness of conservation measures (using fitness traits such as female and hatchling sizes) and examine underlying trends. The aim of this thesis was thus to evaluate the fitness of loggerhead and leatherback sea turtles nesting in South Africa. Long-term female size trends over time were evaluated and the populations were split between first-time nesters and experienced nesters. As sea turtle reproductive output (clutch size only) is correlated with female size and evidence is showing that in some populations individual female size is decreasing, the effects of maternal body size on reproductive output and hatchling fitness were investigated for both species. Crawling and swimming speeds were used as proxies of hatchling fitness, because these two traits positively influence their survival. An oceanic model was further used in combination with a particle tracking framework to estimate, for the first time, post-hatchling dispersal of loggerhead and leatherback turtles in the SWIO. I investigated whether the trend in female size for loggerhead turtles nesting in South Africa is a result of their foraging strategy to determine if there is a foraging dichotomy (neritic and oceanic). Despite an apparent increasing population, a significant 3.7 and 3.6 cm decrease in the size of both recruit and remingrant female loggerhead turtles, but a stable mean size of leatherbacks for both age groups was observed. I hypothesise that these contradictory effects are attributable to the very distinct foraging ecologies of the two turtle species and speculate that these variations in carapace length may be driven by environmental change. The reproductive strategy of both loggerhead and leatherback turtles nesting in South Africa supports the optimal egg size theory with larger turtles producing larger clutches but not larger eggs. Egg size was thus constant irrespective of maternal length. Hatchlings with longer carapaces and flippers had higher swimming speed, suggesting that larger hatchlings are fitter (potentially higher survival) than smaller ones by spending less time in high predation risk areas (i.e. beach and nearshore). The model revealed that dispersal trajectories of both loggerhead and leatherback sea turtle hatchlings were very similar and simulations indicated that initial active swimming (frenzy) as well as variability in oceanic conditions strongly influenced dispersal of virtual hatchlings. The trends observed in this study emphasize the importance of long-term monitoring, examining not only abundance but also individual size, to understand population dynamics, support recovery planning and prioritize future conservation practices. Furthermore, the findings of this study have important implications for overall population growth if smaller hatchlings of lower fitness are produced as a result of climate change and thus have decreased dispersal abilities and lower likelihood of survival.
- Full Text:
- Date Issued: 2020
Investigation of potential induced degradation as a performance limiting defect in photovoltaic modules
- Authors: Kwembur, Isaac Morko
- Date: 2020
- Subjects: Photovoltaic cells
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48423 , vital:40875
- Description: Potential Induced Degradation (PID) impacts negatively on photovoltaic (PV) module durability because it significantly affects the output of PV modules and systems. Unless detected at infancy, PID progression can be catastrophic. This study involved systematic PID stressing of PV modules using a custom-built environmental chamber that can achieve suitable environmental conditions, viz., of the 35 °C ± 1 °C and relative humidity of 75 % ± 5 %. The first part of this work was to induce PID using three approaches: climate chamber testing, inducing PID using a conductive aluminium plate on the surface of the module without touching the frame and a localised PID induction on one cell in a module. The second part is to detect induced PID using Electroluminescence (EL) images taken at current corresponding to 10% Isc, EL histograms analysis and Voc ratio taken at 1000 W/m2 to 200 W/m2 . The third part is to study module regeneration after PID shunting degradation in two ways, viz., forced reverse polarization and natural recovery. The PID detection tools used in this work are well known module characterization techniques such as EL imaging, Infrared imaging, and light and dark current-voltage measurements. These characterisation tools are used in combination to detect defects such as optical losses, cracks, breakage, electric circuit degradation and PID. Under normal testing PID was detected and in some cases, modules were able to recover, while for advanced stage PID regeneration or PID reversal was difficult. This thesis focuses on PID detection at infancy using three approaches; EL imaging at current corresponding to 10% of Isc. Light and dark current – voltage measurements (L-IV & D-IV) and open circuit voltage (Voc) ratios at low irradiance. The early detection procedures are essential in reversing the degradation caused by PID which is reversible. The time taken to reverse the PID degradation will depend on the extent of the degradation. If detected early, it will take a short period of time to completely reverse lost power. Infrared thermography is a non-contact characteristic tool that can be deployed in large scale plants using drones to detect the presence of PID in PV plants. Module performance and device parameters extracted from the L-IV curves on a module before and after PID stress, such as Pmpp, Voc, Isc Fill Factor (FF), shunt resistance (Rsh) and series resistance (Rs) and ideality (n) are sensitive to PID shunting. Voc and Rsh drop significantly with the onset of PID, while Rs increases. The decrease in Voc and Rsh is due to heavy shunting on the module resulting in increased carrier recombination, while the increase in Rs is due to increased shunting paths leading to decreased photocurrent. When substantial degradation on a module occurs Pmpp, FF and n will drop and at very advanced stage of PID degradation Isc may drop excessively.
- Full Text:
- Date Issued: 2020
- Authors: Kwembur, Isaac Morko
- Date: 2020
- Subjects: Photovoltaic cells
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/48423 , vital:40875
- Description: Potential Induced Degradation (PID) impacts negatively on photovoltaic (PV) module durability because it significantly affects the output of PV modules and systems. Unless detected at infancy, PID progression can be catastrophic. This study involved systematic PID stressing of PV modules using a custom-built environmental chamber that can achieve suitable environmental conditions, viz., of the 35 °C ± 1 °C and relative humidity of 75 % ± 5 %. The first part of this work was to induce PID using three approaches: climate chamber testing, inducing PID using a conductive aluminium plate on the surface of the module without touching the frame and a localised PID induction on one cell in a module. The second part is to detect induced PID using Electroluminescence (EL) images taken at current corresponding to 10% Isc, EL histograms analysis and Voc ratio taken at 1000 W/m2 to 200 W/m2 . The third part is to study module regeneration after PID shunting degradation in two ways, viz., forced reverse polarization and natural recovery. The PID detection tools used in this work are well known module characterization techniques such as EL imaging, Infrared imaging, and light and dark current-voltage measurements. These characterisation tools are used in combination to detect defects such as optical losses, cracks, breakage, electric circuit degradation and PID. Under normal testing PID was detected and in some cases, modules were able to recover, while for advanced stage PID regeneration or PID reversal was difficult. This thesis focuses on PID detection at infancy using three approaches; EL imaging at current corresponding to 10% of Isc. Light and dark current – voltage measurements (L-IV & D-IV) and open circuit voltage (Voc) ratios at low irradiance. The early detection procedures are essential in reversing the degradation caused by PID which is reversible. The time taken to reverse the PID degradation will depend on the extent of the degradation. If detected early, it will take a short period of time to completely reverse lost power. Infrared thermography is a non-contact characteristic tool that can be deployed in large scale plants using drones to detect the presence of PID in PV plants. Module performance and device parameters extracted from the L-IV curves on a module before and after PID stress, such as Pmpp, Voc, Isc Fill Factor (FF), shunt resistance (Rsh) and series resistance (Rs) and ideality (n) are sensitive to PID shunting. Voc and Rsh drop significantly with the onset of PID, while Rs increases. The decrease in Voc and Rsh is due to heavy shunting on the module resulting in increased carrier recombination, while the increase in Rs is due to increased shunting paths leading to decreased photocurrent. When substantial degradation on a module occurs Pmpp, FF and n will drop and at very advanced stage of PID degradation Isc may drop excessively.
- Full Text:
- Date Issued: 2020
Investigations into biological control options for Lycium ferocissimum Miers, African Boxthorn (Solanaceae) for Australia
- Authors: Mauda, Evans Vusani
- Date: 2020
- Subjects: Lycium ferocissimum , Solanaceae -- Biological control -- Australia , Weeds -- Control -- Australia , Invasive plants -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insect-plant relationships
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167142 , vital:41441
- Description: Lycium ferocissimum Miers (Solanaceae) (African boxthorn or boxthorn) is a shrub native to South Africa,and has become naturalised and invasive in Australia and New Zealand. The plant is listed on the Noxious Weed List for Australian States and territories. Although other control methods are available, biological control presents a potentially sustainable intervention for reducing populations of this weed in Australia. In South Africa, the plant has been recorded from two allopatric populations, one in the Eastern Cape Province, the other in the Western Cape Provinces, however, there taxonomic and morphological uncertainties are reported in the literature. Therefore, before native range surveys for potential biological control agents could be considered, the taxonomic uncertainty needed to be resolved. The two geographically distinct areas, as well as the Australia population were sampled to assess morphological and genetic variation. All samples collected in Australia were confirmed as L.ferocissimum, with no evidence of hybridisation with any other Lycium species. Nuclear and chloroplast genetic diversity within L.ferocissimum across South Africa was high, and Australia was low, with no evidence of genetic seperation. One ehaplotypes found across Australia was found at only two sites in South Africa, both in the Western Cape, suggesting that the Australian lineage may have originated from this region. Ten samples from South Africa, putatively identified in the field as L.ferocissimum, were genetically characterised as different (unidentified) Lycium species. The majority of plants sampled were confirmed as L.ferocissimum, sharing a common haplotype (haplotype 5) with sampled specimens from Australia. Morphological analyses across different Lycium species in South Africa did not identify any leaf or floral characteristics unique to L.ferocissimum, and thus morphological identification in the native range remains problematic. Surveys for phytophagous in sects on L.ferocissimum were carried out regularly over a two-year period in the two regions. The number of insect species found in the Eastern Cape Province (55) was higher than in the Western Cape Province (41), but insect diversity based on Shannon indices was highest in the Western Cape Province. Indicator species analysis revealed eight insect herbivore species driving the differences in the herbivore communities between the two provinces. Based on insect distribution, abundance, feeding preference and available literature, three species were prioritised as potential biological control agents. These include the leaf-chewing beetles, Cassida distinguenda Spaeth (Chrysomelidae) and Cleta eckloni Mulsant (Coccinellidae), and the leaf-mining weevil, Neoplatygaster serietuberculata Gyllenhal (Curculionidae). Native range studies such as this are perhaps the most technically difficult and logistically time-consuming part of the biological control programme. Yet, the entire outcome of a programme depends on the suite of potential agents feeding on the weed. The information gained during this stage significantly contributed to the prioritization of agents for further host-range testing and possible release. Here we showed how molecular and genetic characterisations of the target weed can be us ed to accurately define the identity and phylogeny of the target species. In addition, the study also highlighted the importance of considering plant morphology and how phenotypic plasticity may influence infield plant identifications while conducting native range surveys. By gaining further information during long-term and wide spread native range surveys we were not just able to provide a list of herbivorous insect fauna and fungi associated with the plant, but were able to prioritise the phytophagous species that held the most potential as biological control agents.
- Full Text:
- Date Issued: 2020
- Authors: Mauda, Evans Vusani
- Date: 2020
- Subjects: Lycium ferocissimum , Solanaceae -- Biological control -- Australia , Weeds -- Control -- Australia , Invasive plants -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insect-plant relationships
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167142 , vital:41441
- Description: Lycium ferocissimum Miers (Solanaceae) (African boxthorn or boxthorn) is a shrub native to South Africa,and has become naturalised and invasive in Australia and New Zealand. The plant is listed on the Noxious Weed List for Australian States and territories. Although other control methods are available, biological control presents a potentially sustainable intervention for reducing populations of this weed in Australia. In South Africa, the plant has been recorded from two allopatric populations, one in the Eastern Cape Province, the other in the Western Cape Provinces, however, there taxonomic and morphological uncertainties are reported in the literature. Therefore, before native range surveys for potential biological control agents could be considered, the taxonomic uncertainty needed to be resolved. The two geographically distinct areas, as well as the Australia population were sampled to assess morphological and genetic variation. All samples collected in Australia were confirmed as L.ferocissimum, with no evidence of hybridisation with any other Lycium species. Nuclear and chloroplast genetic diversity within L.ferocissimum across South Africa was high, and Australia was low, with no evidence of genetic seperation. One ehaplotypes found across Australia was found at only two sites in South Africa, both in the Western Cape, suggesting that the Australian lineage may have originated from this region. Ten samples from South Africa, putatively identified in the field as L.ferocissimum, were genetically characterised as different (unidentified) Lycium species. The majority of plants sampled were confirmed as L.ferocissimum, sharing a common haplotype (haplotype 5) with sampled specimens from Australia. Morphological analyses across different Lycium species in South Africa did not identify any leaf or floral characteristics unique to L.ferocissimum, and thus morphological identification in the native range remains problematic. Surveys for phytophagous in sects on L.ferocissimum were carried out regularly over a two-year period in the two regions. The number of insect species found in the Eastern Cape Province (55) was higher than in the Western Cape Province (41), but insect diversity based on Shannon indices was highest in the Western Cape Province. Indicator species analysis revealed eight insect herbivore species driving the differences in the herbivore communities between the two provinces. Based on insect distribution, abundance, feeding preference and available literature, three species were prioritised as potential biological control agents. These include the leaf-chewing beetles, Cassida distinguenda Spaeth (Chrysomelidae) and Cleta eckloni Mulsant (Coccinellidae), and the leaf-mining weevil, Neoplatygaster serietuberculata Gyllenhal (Curculionidae). Native range studies such as this are perhaps the most technically difficult and logistically time-consuming part of the biological control programme. Yet, the entire outcome of a programme depends on the suite of potential agents feeding on the weed. The information gained during this stage significantly contributed to the prioritization of agents for further host-range testing and possible release. Here we showed how molecular and genetic characterisations of the target weed can be us ed to accurately define the identity and phylogeny of the target species. In addition, the study also highlighted the importance of considering plant morphology and how phenotypic plasticity may influence infield plant identifications while conducting native range surveys. By gaining further information during long-term and wide spread native range surveys we were not just able to provide a list of herbivorous insect fauna and fungi associated with the plant, but were able to prioritise the phytophagous species that held the most potential as biological control agents.
- Full Text:
- Date Issued: 2020
IsiXhosa as the language of teaching and learning mathematics in Grade Six: investigating the mother tongue based bilingual education mathematics pilot in the Eastern Cape Province, South Africa
- Authors: Mbude, Naledi Ntombizanele
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Education, Bilingual -- South Africa , Native language and education -- South Africa , Language policy -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/143262 , vital:38215
- Description: This study is an investigation on lessons learnt when the language of learners is maintained for teaching and learning mathematics beyond Grade 3 for another 3 years. It is undertaken in Cofimvaba, a rural village of the Eastern Cape in South Africa. We investigate lessons that can be learnt from the Mother Tongue based- Bilingual Education (MTbBE) strategy, that can be replicated. South Africa post-1994 has a Language-in-Education Policy (1997) that provides for the use of all official languages as Languages of Teaching and Learning (LoLT), this has remained on paper as the schooling system focusses on an early –exit model of three years of the Mother Tongue Education (MTE) for the Foundation Phase (FP) then exit to English instruction in Grade 4; this applies to African language learners only. English and Afrikaans speakers have mother tongue education from cradle to university; a benefit they have enjoyed pre- and post-apartheid. Various studies have been conducted to understand the relationship between language and mathematics learning as it is crucial to design mathematics instruction for students who are English Learners (ELs) and/or bilingual. However, in South Africa, there had not been a direct exploration of the achievement of learners in mathematics when their mother tongue is used and sustained throughout the first six years of learning mathematics, while English is a supportive resource. This is the focus of this study. The study lends itself to the adoption of a mixed methods design (QUALT+QUANT), while also employing documents, observation and test scores of learners to obtain data. Content analysis and thematic analysis approaches were used in analyzing the qualitative-type data while a statistical approach was used in the analysis of quantitative data. The main aim of the study was to establish whether in the Cofimvaba pilot, there is any evidence to make a case for extending Mother Tongue Based-bilingual Education (MTBBE) beyond Grade 3 for black African children. Another aim, was to highlight and document the effort that was the first of its kind in South Africa, undertaken in a small rural area to develop isiXhosa as language of Mathematics and Science. The most salient of this effort was the fact that it was underpinned by deliberate theoretical and empirical foundations central to language policy and planning. The finding of this study is that the use of isiXhosa for MTbBE was effective for boosting mathematical and science skills in the mother tongue and English in Grade 6 as demonstrated in Chapter 7 and 8. Lastly, this study demonstrates the power of political will and how a decision backed by financial investment can transform the wider system despite the challenges of transformation. For the first time in the history of education; a poor department has stuck to its guns; unwearied by the negativity surrounding the development of African languages. It committed to the cause of improving the academic achievement of the poorest of the poor. Historically, in implementing a Mathematics Curriculum, the Department of Education (both officials and teachers) has never efficiently implemented the LiEP (1997) in the manner spelt out in its policy documents viz, multilingualism as the norm. The focus has been on a perspective of learners who are learning and must English, then mathematics and ways to get them to know English at all costs. This view creates inequities in the classroom because it places emphasis on what learners don’t know or can’t do. In contrast, this study proposes a sociocultural perspective that shifts away from deficiency models of bilingual learners and instead focuses on describing the resources bilingual students use to communicate mathematically (Moskovich, 1988). Without this shift we will have a limited view of these learners and will design instruction that neglects the competencies they bring to mathematics classrooms. If, instead, we learn to recognize the mathematical ideas these students express in spite of their accents, code-switching, or missing vocabulary, then instruction can build on students’ competencies and resources (Moskovich, 1998). This study recommends a plethora of strategies that must be taken by the Department of Education to widen epistemological access to mathematics for African language learners using MTbBE as a viable strategy.
- Full Text:
- Date Issued: 2020
- Authors: Mbude, Naledi Ntombizanele
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Education, Bilingual -- South Africa , Native language and education -- South Africa , Language policy -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/143262 , vital:38215
- Description: This study is an investigation on lessons learnt when the language of learners is maintained for teaching and learning mathematics beyond Grade 3 for another 3 years. It is undertaken in Cofimvaba, a rural village of the Eastern Cape in South Africa. We investigate lessons that can be learnt from the Mother Tongue based- Bilingual Education (MTbBE) strategy, that can be replicated. South Africa post-1994 has a Language-in-Education Policy (1997) that provides for the use of all official languages as Languages of Teaching and Learning (LoLT), this has remained on paper as the schooling system focusses on an early –exit model of three years of the Mother Tongue Education (MTE) for the Foundation Phase (FP) then exit to English instruction in Grade 4; this applies to African language learners only. English and Afrikaans speakers have mother tongue education from cradle to university; a benefit they have enjoyed pre- and post-apartheid. Various studies have been conducted to understand the relationship between language and mathematics learning as it is crucial to design mathematics instruction for students who are English Learners (ELs) and/or bilingual. However, in South Africa, there had not been a direct exploration of the achievement of learners in mathematics when their mother tongue is used and sustained throughout the first six years of learning mathematics, while English is a supportive resource. This is the focus of this study. The study lends itself to the adoption of a mixed methods design (QUALT+QUANT), while also employing documents, observation and test scores of learners to obtain data. Content analysis and thematic analysis approaches were used in analyzing the qualitative-type data while a statistical approach was used in the analysis of quantitative data. The main aim of the study was to establish whether in the Cofimvaba pilot, there is any evidence to make a case for extending Mother Tongue Based-bilingual Education (MTBBE) beyond Grade 3 for black African children. Another aim, was to highlight and document the effort that was the first of its kind in South Africa, undertaken in a small rural area to develop isiXhosa as language of Mathematics and Science. The most salient of this effort was the fact that it was underpinned by deliberate theoretical and empirical foundations central to language policy and planning. The finding of this study is that the use of isiXhosa for MTbBE was effective for boosting mathematical and science skills in the mother tongue and English in Grade 6 as demonstrated in Chapter 7 and 8. Lastly, this study demonstrates the power of political will and how a decision backed by financial investment can transform the wider system despite the challenges of transformation. For the first time in the history of education; a poor department has stuck to its guns; unwearied by the negativity surrounding the development of African languages. It committed to the cause of improving the academic achievement of the poorest of the poor. Historically, in implementing a Mathematics Curriculum, the Department of Education (both officials and teachers) has never efficiently implemented the LiEP (1997) in the manner spelt out in its policy documents viz, multilingualism as the norm. The focus has been on a perspective of learners who are learning and must English, then mathematics and ways to get them to know English at all costs. This view creates inequities in the classroom because it places emphasis on what learners don’t know or can’t do. In contrast, this study proposes a sociocultural perspective that shifts away from deficiency models of bilingual learners and instead focuses on describing the resources bilingual students use to communicate mathematically (Moskovich, 1988). Without this shift we will have a limited view of these learners and will design instruction that neglects the competencies they bring to mathematics classrooms. If, instead, we learn to recognize the mathematical ideas these students express in spite of their accents, code-switching, or missing vocabulary, then instruction can build on students’ competencies and resources (Moskovich, 1998). This study recommends a plethora of strategies that must be taken by the Department of Education to widen epistemological access to mathematics for African language learners using MTbBE as a viable strategy.
- Full Text:
- Date Issued: 2020
Joint Modelling Inference for Longitudinal and Time To Event Data with Application to Biomarkers in Medical and Clinical Studies
- Authors: Azeez, Adeboye Nurudeen
- Date: 2020
- Subjects: Biochemical markers Bayesian statistical decision theory
- Language: English
- Type: Thesis , Doctoral , PhD (Biostatistics)
- Identifier: http://hdl.handle.net/10353/18476 , vital:42543
- Description: In the past couple of decades, longitudinal and survival data analysis have emerged as important and popular concepts of biostatistics and statistics for disease modelling. In recent years, these two statistics concepts have been combined to develop a joint model for longitudinal and survival data analysis. The Joint model is a simultaneous modelling application of longitudinal and survival data while taking into account a possible association between them. In this thesis, three sub-topics (Conditional score approach, estimating equation approach, and modified Cholesky decomposition approach) are utilised to model the association if the independence assumption is violated. Using the conditional score approach, the study investigated the association between longitudinal covariates and the time-to-event process to examine the within-subject measurement error that could influence estimation when the assumption of normality and mutual independence is violated. Given the assumption violation, I proposed an estimating equation approach based on the conditional score to relax parametric distributional assumptions for repeated measures of random effects. I jointly modelled the time-dependent biomarkers and event times using the Cox model with intermittent time-dependent covariates measure, in which the longitudinal model was used to characterize the biomarker underlying (unobservable) trajectory and incorporated as a latent time-dependent covariate in the survival model to predict failure times. Estimates of the parameters were obtained by a restricted maximum likelihood estimate (REML). A modified Cholesky decomposition method was used to capture the within-subject covariance for a positive definite and symmetric matrix, with the assumption that the observed data from different subjects are independent. I illustrated the proposed method by a real data set from a lung study and simulation. An extension to the joint model of longitudinal-survival data was also proposed, in which the longitudinal data has a cumulative and weighted effect on the hazard event function. Using a Bayesian parametric method, I proposed a skewed weighted probability density function to estimate the parameters. The weighted cumulative effect used enabled different longitudinal profiles to be incorporated over time in calculating the hazard ratio between the subjects. The proposed functions provide greater flexibility for modelling the association structure of different longitudinal and survival sub-model. The focus was on the association between the biomarker (serum creatinine, sCr) and the development of end-stage renal disease (ESRD). Since the effect of sCr biomarker is anticipated to be a cumulative effect, with the development of sCr biomarker over time leading to progressively higher damage of the kidney. The approach was applied a simulation for validation of the proposed method
- Full Text:
- Date Issued: 2020
- Authors: Azeez, Adeboye Nurudeen
- Date: 2020
- Subjects: Biochemical markers Bayesian statistical decision theory
- Language: English
- Type: Thesis , Doctoral , PhD (Biostatistics)
- Identifier: http://hdl.handle.net/10353/18476 , vital:42543
- Description: In the past couple of decades, longitudinal and survival data analysis have emerged as important and popular concepts of biostatistics and statistics for disease modelling. In recent years, these two statistics concepts have been combined to develop a joint model for longitudinal and survival data analysis. The Joint model is a simultaneous modelling application of longitudinal and survival data while taking into account a possible association between them. In this thesis, three sub-topics (Conditional score approach, estimating equation approach, and modified Cholesky decomposition approach) are utilised to model the association if the independence assumption is violated. Using the conditional score approach, the study investigated the association between longitudinal covariates and the time-to-event process to examine the within-subject measurement error that could influence estimation when the assumption of normality and mutual independence is violated. Given the assumption violation, I proposed an estimating equation approach based on the conditional score to relax parametric distributional assumptions for repeated measures of random effects. I jointly modelled the time-dependent biomarkers and event times using the Cox model with intermittent time-dependent covariates measure, in which the longitudinal model was used to characterize the biomarker underlying (unobservable) trajectory and incorporated as a latent time-dependent covariate in the survival model to predict failure times. Estimates of the parameters were obtained by a restricted maximum likelihood estimate (REML). A modified Cholesky decomposition method was used to capture the within-subject covariance for a positive definite and symmetric matrix, with the assumption that the observed data from different subjects are independent. I illustrated the proposed method by a real data set from a lung study and simulation. An extension to the joint model of longitudinal-survival data was also proposed, in which the longitudinal data has a cumulative and weighted effect on the hazard event function. Using a Bayesian parametric method, I proposed a skewed weighted probability density function to estimate the parameters. The weighted cumulative effect used enabled different longitudinal profiles to be incorporated over time in calculating the hazard ratio between the subjects. The proposed functions provide greater flexibility for modelling the association structure of different longitudinal and survival sub-model. The focus was on the association between the biomarker (serum creatinine, sCr) and the development of end-stage renal disease (ESRD). Since the effect of sCr biomarker is anticipated to be a cumulative effect, with the development of sCr biomarker over time leading to progressively higher damage of the kidney. The approach was applied a simulation for validation of the proposed method
- Full Text:
- Date Issued: 2020
Journeying home, exile and transnationalism in Noni Jabavu and Sisonke Msimang’s memoirs
- Authors: Masola, Athambile
- Date: 2020
- Subjects: Home in literature , Exile (Punishment) in literature , Women authors, Black -- South Africa -- History and criticism , Jabavu, Noni -- Criticism and interpretation , Msimang, Sisonke -- Criticism and interpretation
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166529 , vital:41376
- Description: This thesis examines the memoirs of two South Africa female writers: Noni Jabavu and Sisonke Msimang. In analysing their memoirs, this thesis sets out to contribute to the scholarship which centres the voices of Black women writers. It explores how both writers interrogate the concepts of home, exile and transnationalism. My focus is on the ways in which the writers theorise questions of belonging, and the extent to which their writing provides the opportunity to give voice to the complex nature of belonging. I read the narratives from these two writers alongside each other, as Noni Jabavu is Sisonke Msimang’s literary ancestor. By looking at their works alongside each other, this thesis becomes an intergenerational conversation between the past and the present. Using Black feminist thought and migratory subjectivity, this thesis examines the ways in which these writers connect the personal and the political. Noni and Sisonke navigate the private spaces of home in conversation with the political experience of exile and the nation. In the second chapter, I explore home as ekhaya, isizwe and an imaginary homeland. Ekhaya is the isiXhosa word denoting the family home, where there is a network of family rather than a nuclear family. Home is also isizwe: the isiXhosa word which evokes the nation state, which takes on layered meanings in the context of colonialism and apartheid. Home can also be an imaginary homeland, which is an imagined version of home after a long absence such as exile. In the third chapter, I examine three forms of exile: internal exile, estrangement and political exile. Finally, in chapter four, I analyse transnationalism: a border-crossing which raises questions of power, mobility and kinship. Looking at home, exile and transnationalism together allows for an exploration which challenges taken-for-granted ideas about place and identity. These memoirs illuminate the ways in which Black women constitute and reconstitute their identities according to the places which they access through travel.
- Full Text:
- Date Issued: 2020
- Authors: Masola, Athambile
- Date: 2020
- Subjects: Home in literature , Exile (Punishment) in literature , Women authors, Black -- South Africa -- History and criticism , Jabavu, Noni -- Criticism and interpretation , Msimang, Sisonke -- Criticism and interpretation
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166529 , vital:41376
- Description: This thesis examines the memoirs of two South Africa female writers: Noni Jabavu and Sisonke Msimang. In analysing their memoirs, this thesis sets out to contribute to the scholarship which centres the voices of Black women writers. It explores how both writers interrogate the concepts of home, exile and transnationalism. My focus is on the ways in which the writers theorise questions of belonging, and the extent to which their writing provides the opportunity to give voice to the complex nature of belonging. I read the narratives from these two writers alongside each other, as Noni Jabavu is Sisonke Msimang’s literary ancestor. By looking at their works alongside each other, this thesis becomes an intergenerational conversation between the past and the present. Using Black feminist thought and migratory subjectivity, this thesis examines the ways in which these writers connect the personal and the political. Noni and Sisonke navigate the private spaces of home in conversation with the political experience of exile and the nation. In the second chapter, I explore home as ekhaya, isizwe and an imaginary homeland. Ekhaya is the isiXhosa word denoting the family home, where there is a network of family rather than a nuclear family. Home is also isizwe: the isiXhosa word which evokes the nation state, which takes on layered meanings in the context of colonialism and apartheid. Home can also be an imaginary homeland, which is an imagined version of home after a long absence such as exile. In the third chapter, I examine three forms of exile: internal exile, estrangement and political exile. Finally, in chapter four, I analyse transnationalism: a border-crossing which raises questions of power, mobility and kinship. Looking at home, exile and transnationalism together allows for an exploration which challenges taken-for-granted ideas about place and identity. These memoirs illuminate the ways in which Black women constitute and reconstitute their identities according to the places which they access through travel.
- Full Text:
- Date Issued: 2020
Learning styles, availability, and utilization of instructional materials as correlates of grade 6 learners’ mathematics performance in Buffalo city
- Authors: Adu, Kemi Olajumoke
- Date: 2020
- Subjects: Learning ability
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/11374 , vital:39066
- Description: Mathematics is the foundation for the economic and technological development of any nation. It has been asserted that Mathematics is expected to help in accelerating social, economic and technological progress of any society. Performance of this subject is very important and there are different types of learners; such auditory, visual, and kinesthetic. Auditory learners appreciate listening to the teachers and sit down close to the teachers in class. Visual learners like to see things physically during teaching. They learn by materials like charts, graphs, and pictures. Kinesthetic learners learn by doing. Students can prefer one, two, or three learning styles; all these are subject to the availability of instructional materials. The Primary school level is very important in any educational system and any lack at this level would permeate to other levels of the educational system. Hence, this thesis examines the Learning Styles, Availability, and Utilization of Instructional Materials as Correlates of Grade 6 Learners’ Mathematics Performance in Buffalo City. The study adopted the positivist paradigm and employed the quantitative approach in investigating the phenomenon. The thesis made use of correlational research design as it attempted to find out the effects of learning styles and instructional materials on learners’ performance in Mathematics. Stratified sampling was used to select participants. Stratified sampling is a process of dividing the sample frame into strata to obtain relatively homogenous subgroups; this gave us 1225 Grade 6 learners selected across 35 schools in Buffalo City as the sample of the study. Three instruments which are Students’ Learning Styles Scale (SLSS), Availability and Utilization of Instructional Materials Inventory (AUIMI), and Mathematics Achievement Test (MAT) whose reliability co-efficient are; 0.87, 0.78 and 0.89 respectively. The data collected were analysed using descriptive and inferential statistics. The findings of the study revealed among others; students learning style (visual, auditory, and kinesthetic) have a significant relationship on Grade 6 learners Mathematics performance (B=-.113, t=-3.886, p<0.05). Students learning style (∆R2=.012, ∆F (1, 1223) = 5.047, p < 0.05) emerged as the best predictor of Grade 6 learners Mathematics performance in Buffalo City, while the availability and utilization of instructional materials (∆R2 = .000), ∆F (1,223) = .018, P > 0.05), and gender (∆R2 = .000, ∆F (1,1223) = .036, p>0.05) emerged as better predictors. The study further iv revealed that, Grade six learners with visual learning style ( = 13.242, SD = 5.565) had the best performance in Mathematics at Buffalo City, followed by learners with auditory learning style ( = 12.996, SD = 3.883), and learners with Kinaesthetic learning style ( = 11.525, SD =3.800). The study concluded that one of the most fundamental issues to consider in improving Mathematics performance is the understanding of the learners’ learning styles and effective use of appropriate instructional materials for teaching Mathematics.
- Full Text:
- Date Issued: 2020
- Authors: Adu, Kemi Olajumoke
- Date: 2020
- Subjects: Learning ability
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/11374 , vital:39066
- Description: Mathematics is the foundation for the economic and technological development of any nation. It has been asserted that Mathematics is expected to help in accelerating social, economic and technological progress of any society. Performance of this subject is very important and there are different types of learners; such auditory, visual, and kinesthetic. Auditory learners appreciate listening to the teachers and sit down close to the teachers in class. Visual learners like to see things physically during teaching. They learn by materials like charts, graphs, and pictures. Kinesthetic learners learn by doing. Students can prefer one, two, or three learning styles; all these are subject to the availability of instructional materials. The Primary school level is very important in any educational system and any lack at this level would permeate to other levels of the educational system. Hence, this thesis examines the Learning Styles, Availability, and Utilization of Instructional Materials as Correlates of Grade 6 Learners’ Mathematics Performance in Buffalo City. The study adopted the positivist paradigm and employed the quantitative approach in investigating the phenomenon. The thesis made use of correlational research design as it attempted to find out the effects of learning styles and instructional materials on learners’ performance in Mathematics. Stratified sampling was used to select participants. Stratified sampling is a process of dividing the sample frame into strata to obtain relatively homogenous subgroups; this gave us 1225 Grade 6 learners selected across 35 schools in Buffalo City as the sample of the study. Three instruments which are Students’ Learning Styles Scale (SLSS), Availability and Utilization of Instructional Materials Inventory (AUIMI), and Mathematics Achievement Test (MAT) whose reliability co-efficient are; 0.87, 0.78 and 0.89 respectively. The data collected were analysed using descriptive and inferential statistics. The findings of the study revealed among others; students learning style (visual, auditory, and kinesthetic) have a significant relationship on Grade 6 learners Mathematics performance (B=-.113, t=-3.886, p<0.05). Students learning style (∆R2=.012, ∆F (1, 1223) = 5.047, p < 0.05) emerged as the best predictor of Grade 6 learners Mathematics performance in Buffalo City, while the availability and utilization of instructional materials (∆R2 = .000), ∆F (1,223) = .018, P > 0.05), and gender (∆R2 = .000, ∆F (1,1223) = .036, p>0.05) emerged as better predictors. The study further iv revealed that, Grade six learners with visual learning style ( = 13.242, SD = 5.565) had the best performance in Mathematics at Buffalo City, followed by learners with auditory learning style ( = 12.996, SD = 3.883), and learners with Kinaesthetic learning style ( = 11.525, SD =3.800). The study concluded that one of the most fundamental issues to consider in improving Mathematics performance is the understanding of the learners’ learning styles and effective use of appropriate instructional materials for teaching Mathematics.
- Full Text:
- Date Issued: 2020
Localising the global: the use of a postmodernist aesthetic in the fiction of Alain Mabanckou
- Authors: Ngulube, Innocent Akilimale
- Date: 2020
- Subjects: Mabanckou, Alain, 1966- , Mabanckou, Alain, 1966- -- Blue, white, red , Mabanckou, Alain, 1966- -- African psycho , Mabanckou, Alain, 1966- -- Broken glass , Mabanckou, Alain, 1966- -- Memoirs of a porcupine , Mabanckou, Alain, 1966- -- The Lights of Pointe-Noire , Mabanckou, Alain, 1966- -- Tomorrow I'll be twenty , Mabanckou, Alain, 1966- Black bazaar , Postcolonialism in literature , African fiction (French) -- History and criticism , Postmodernism (Literature)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167153 , vital:41442
- Description: This thesis explores the use of a postmodernist aesth etic in Alain Mabanckou’s oeuvre, namely Blue White Red, African Psycho, Broken Glass, Memoirs of a Porcupine, Black Bazaar, Tomorrow I’ll Be Twenty, The Lights of Pointe-Noire, and Black Moses. In particular, I show how and why this Afrodiasporic author localises strategies associated with Western postmodernist writing in an African postcolonial context. My central argument is that if postmodernism is a critique of modernity in the West, then it must also be a respon se to enforced modernity in the African postcolonial context. In mounting this argument, I conduct a close reading of Mabanckou’s novels from within the theoretical frameworks of postmodernism and postcolonialism. I demonstrate that Mabanckou’s writing adu mbrates the possibility of a postcolonial postmodernism. Since he is a French-Congolese citizen, his writing evinces aesthetic glocalisation. That is, as a postcolonial writer, he conceives of, and inflects, postmodernism differently from a Western writer, for his experiences of and responses to modernity differ from the latter’s. Far from replicating a politics of disillusionment and despair that informs, even characterises, Western postmodernist fiction, Mabanckou invests hi s African postcolonial writing with a politics of decolonis ation which problematises the effects of enforced modernity. Postmodernism, in other words, accords Mabanckou an ambivalent position from which he interrogates both Western modernity and its African version. Significantly, in this regard, Mabanckou’s writing presents both an extension of and a departure from the pioneering influence of the first generation of African writers such as Chinua Achebe, Ngugi wa Thiong’o, and Wole Soyinka.
- Full Text:
- Date Issued: 2020
- Authors: Ngulube, Innocent Akilimale
- Date: 2020
- Subjects: Mabanckou, Alain, 1966- , Mabanckou, Alain, 1966- -- Blue, white, red , Mabanckou, Alain, 1966- -- African psycho , Mabanckou, Alain, 1966- -- Broken glass , Mabanckou, Alain, 1966- -- Memoirs of a porcupine , Mabanckou, Alain, 1966- -- The Lights of Pointe-Noire , Mabanckou, Alain, 1966- -- Tomorrow I'll be twenty , Mabanckou, Alain, 1966- Black bazaar , Postcolonialism in literature , African fiction (French) -- History and criticism , Postmodernism (Literature)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167153 , vital:41442
- Description: This thesis explores the use of a postmodernist aesth etic in Alain Mabanckou’s oeuvre, namely Blue White Red, African Psycho, Broken Glass, Memoirs of a Porcupine, Black Bazaar, Tomorrow I’ll Be Twenty, The Lights of Pointe-Noire, and Black Moses. In particular, I show how and why this Afrodiasporic author localises strategies associated with Western postmodernist writing in an African postcolonial context. My central argument is that if postmodernism is a critique of modernity in the West, then it must also be a respon se to enforced modernity in the African postcolonial context. In mounting this argument, I conduct a close reading of Mabanckou’s novels from within the theoretical frameworks of postmodernism and postcolonialism. I demonstrate that Mabanckou’s writing adu mbrates the possibility of a postcolonial postmodernism. Since he is a French-Congolese citizen, his writing evinces aesthetic glocalisation. That is, as a postcolonial writer, he conceives of, and inflects, postmodernism differently from a Western writer, for his experiences of and responses to modernity differ from the latter’s. Far from replicating a politics of disillusionment and despair that informs, even characterises, Western postmodernist fiction, Mabanckou invests hi s African postcolonial writing with a politics of decolonis ation which problematises the effects of enforced modernity. Postmodernism, in other words, accords Mabanckou an ambivalent position from which he interrogates both Western modernity and its African version. Significantly, in this regard, Mabanckou’s writing presents both an extension of and a departure from the pioneering influence of the first generation of African writers such as Chinua Achebe, Ngugi wa Thiong’o, and Wole Soyinka.
- Full Text:
- Date Issued: 2020
Long Waves of Strikes in South Africa: 1886–2019
- Authors: Cottle, Eddie
- Date: 2020
- Subjects: Strikes and lockouts South Africa , Long waves (Economics) South Africa , Business cycles South Africa , Industrial mobilization South Africa , Collective bargaining South Africa , Institutionalisation , Labor unions South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163228 , vital:41020 , doi:10.21504/10962/163228
- Description: Thesis (PhD)--Rhodes University, Faculty of Humanities, Institute for Social and Economic Research (ISER), 2020.
- Full Text:
- Date Issued: 2020
- Authors: Cottle, Eddie
- Date: 2020
- Subjects: Strikes and lockouts South Africa , Long waves (Economics) South Africa , Business cycles South Africa , Industrial mobilization South Africa , Collective bargaining South Africa , Institutionalisation , Labor unions South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163228 , vital:41020 , doi:10.21504/10962/163228
- Description: Thesis (PhD)--Rhodes University, Faculty of Humanities, Institute for Social and Economic Research (ISER), 2020.
- Full Text:
- Date Issued: 2020
Making South African tertiary education multilingual: the implementation, monitoring and evaluation of SANTED Multilingualism Projects 2007 – 2010
- Authors: Nosilela, Bulelwa
- Date: 2020
- Subjects: South Africa-Norway Tertiary Education Development Programme , Language policy -- South Africa , Multilingual education -- South Africa , Language and education -- South Africa , Education, Higher -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/140513 , vital:37895
- Description: This thesis focuses on multilingualism as it applies to education, particularly higher education in South Africa. The thesis suggests that language must be seen as critical in education (Obanya, 2004; Wolff, 2006). This thesis also suggests that there is a link between a person’s general competence in an educational environment, and that person’s language competence. In support of other scholars, this thesis also finds that learners from low social classes in society have a restricted linguistic code and therefore the learners from these social classes lack the ability to express themselves in an elaborative manner in a cognitive situation while learners from upper social class have an elaborate linguistic repertoire in the language of instruction, namely English. Even though general policy in South Africa and Africa as a whole recognises this relationship between language and education, this thesis finds that very little is being done to implement these well-meaning policies. The SANTED (South Africa-Norway-Tertiary-Education) programme, which forms the focus of this thesis, is seen as an exception. While there is an increase in the number of learners and students accessing centres of learning, especially those from historically-disadvantaged backgrounds (CHE Higher Education Monitor, 2008), there is at the same time rigorous debate in South Africa at the moment as to whether these learners and students benefit optimally from knowledge offered in centres of learning, and are therefore, not accomplishing success expected from them (Boughey, 2008). This thesis suggests that at the centre of this debate is the understanding that, while there are a variety of factors that might affect their success, for example social and economic status, schooling background in case of students in higher education, language plays a pivotal role. This thesis analyses the challenges and successes which faced the SANTED programme at a number of South African institutions where language issues were brought to the centre of the learning process. The thesis also assesses best practices in various African countries and makes recommendations regarding language-use in Higher Education, as part of a transformationprocess. The collaboration between the South African and Norwegian governments provided impetus to policy implementation. It also had other focus areas such as capacity building, access, success and retention and collaboration with Southern African Developing Countries (SADC). This thesis shows, through a critical analysis of SANTED, that it represented an important intervention regarding the promotion of multilingualism.
- Full Text:
- Date Issued: 2020
- Authors: Nosilela, Bulelwa
- Date: 2020
- Subjects: South Africa-Norway Tertiary Education Development Programme , Language policy -- South Africa , Multilingual education -- South Africa , Language and education -- South Africa , Education, Higher -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/140513 , vital:37895
- Description: This thesis focuses on multilingualism as it applies to education, particularly higher education in South Africa. The thesis suggests that language must be seen as critical in education (Obanya, 2004; Wolff, 2006). This thesis also suggests that there is a link between a person’s general competence in an educational environment, and that person’s language competence. In support of other scholars, this thesis also finds that learners from low social classes in society have a restricted linguistic code and therefore the learners from these social classes lack the ability to express themselves in an elaborative manner in a cognitive situation while learners from upper social class have an elaborate linguistic repertoire in the language of instruction, namely English. Even though general policy in South Africa and Africa as a whole recognises this relationship between language and education, this thesis finds that very little is being done to implement these well-meaning policies. The SANTED (South Africa-Norway-Tertiary-Education) programme, which forms the focus of this thesis, is seen as an exception. While there is an increase in the number of learners and students accessing centres of learning, especially those from historically-disadvantaged backgrounds (CHE Higher Education Monitor, 2008), there is at the same time rigorous debate in South Africa at the moment as to whether these learners and students benefit optimally from knowledge offered in centres of learning, and are therefore, not accomplishing success expected from them (Boughey, 2008). This thesis suggests that at the centre of this debate is the understanding that, while there are a variety of factors that might affect their success, for example social and economic status, schooling background in case of students in higher education, language plays a pivotal role. This thesis analyses the challenges and successes which faced the SANTED programme at a number of South African institutions where language issues were brought to the centre of the learning process. The thesis also assesses best practices in various African countries and makes recommendations regarding language-use in Higher Education, as part of a transformationprocess. The collaboration between the South African and Norwegian governments provided impetus to policy implementation. It also had other focus areas such as capacity building, access, success and retention and collaboration with Southern African Developing Countries (SADC). This thesis shows, through a critical analysis of SANTED, that it represented an important intervention regarding the promotion of multilingualism.
- Full Text:
- Date Issued: 2020
Managing the corporate reputation of a transforming organisation: a study of multimedia University of Kenya
- Authors: Mtange, Margaret Mulekani
- Date: 2020
- Subjects: Organizational change -- Management , Universities and colleges -- Kenya -- Sociological aspects -- Case studies , Universities and colleges -- Research -- Economic aspects -- Kenya -- Case studies
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50837 , vital:42873
- Description: Universities, like other organisations, are challenged to manage corporate identity and reputation to maintain a competitive edge. Few studies in Africa focus on the impact of internal communication on corporate identity and reputation management during organisational transformation. Thus, this study interrogated how a transforming and complex university in Kenya managed the corporate identity, image and reputation for competitive advantage. The purpose of the study was to establish how Multimedia University of Kenya (MMU) management communicated with its employees to nurture the corporate identity, image and reputation during a ten-year period of transformation. The study draws insights from in-depth interviews with 23 university management members, 178 self-administered questionnaires through random stratification of MMU employees, and content review of two MMU strategic plans ranging from 2011 to 2021. The findings suggest that MMU management used formal and interactive channels to create awareness of organisational transformation. These channels included face-to-face engagements, formal meetings and mediated communication through telephone conversations and intranet that facilitated record keeping. The management engaged in top-down and bottom-up communication to build employee trust, while employees expressed reservations of bottom-up information accuracy, suggesting information exclusion. On the contrary, the employees preferred digital and interpersonal channels for internal communication, which included telephone conversations, social media, personal visits by MMU management, and university events. Publicity activities were to disseminate information to prospective students and sponsors through selected private television, vernacular radio, and MMU radio stations, traditional print media, and the MMU website to communicate the MMU brand and image. Employees acknowledged that MMU brands itself as a leader in telecommunication, technology, mechanical, manufacturing, and media training through state-of-the-art equipment, robust faculty, and problem-solving ventures through research. The current study proposes stronger employee involvement, executive packaging and positioning, coaching successful faculty members as brand ambassadors, retraining employees, and employee participation in policy formulation to enhance new culture. In addition, these opositions will enhance the corporate identity, brand, as well as university performance, product quality, policy and processes to enrich the corporate reputation during transformation. The findings challenge university management to actively engage the corporate communication function, emphasise employee participation, and focus on the continual improvement of corporate identity and reputation management practices for competitive advantage. The current study proposes a participative, multi-layered and multi-dimensional communication model for efficient and excellent internal communication. The current study recommends that corporate communication practitioner be strategically positioned to coordinate employee engagement, utilise appropriate communication channels and counsel university management on corporate identity, image and reputation management during organisational transformation.
- Full Text:
- Date Issued: 2020
- Authors: Mtange, Margaret Mulekani
- Date: 2020
- Subjects: Organizational change -- Management , Universities and colleges -- Kenya -- Sociological aspects -- Case studies , Universities and colleges -- Research -- Economic aspects -- Kenya -- Case studies
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50837 , vital:42873
- Description: Universities, like other organisations, are challenged to manage corporate identity and reputation to maintain a competitive edge. Few studies in Africa focus on the impact of internal communication on corporate identity and reputation management during organisational transformation. Thus, this study interrogated how a transforming and complex university in Kenya managed the corporate identity, image and reputation for competitive advantage. The purpose of the study was to establish how Multimedia University of Kenya (MMU) management communicated with its employees to nurture the corporate identity, image and reputation during a ten-year period of transformation. The study draws insights from in-depth interviews with 23 university management members, 178 self-administered questionnaires through random stratification of MMU employees, and content review of two MMU strategic plans ranging from 2011 to 2021. The findings suggest that MMU management used formal and interactive channels to create awareness of organisational transformation. These channels included face-to-face engagements, formal meetings and mediated communication through telephone conversations and intranet that facilitated record keeping. The management engaged in top-down and bottom-up communication to build employee trust, while employees expressed reservations of bottom-up information accuracy, suggesting information exclusion. On the contrary, the employees preferred digital and interpersonal channels for internal communication, which included telephone conversations, social media, personal visits by MMU management, and university events. Publicity activities were to disseminate information to prospective students and sponsors through selected private television, vernacular radio, and MMU radio stations, traditional print media, and the MMU website to communicate the MMU brand and image. Employees acknowledged that MMU brands itself as a leader in telecommunication, technology, mechanical, manufacturing, and media training through state-of-the-art equipment, robust faculty, and problem-solving ventures through research. The current study proposes stronger employee involvement, executive packaging and positioning, coaching successful faculty members as brand ambassadors, retraining employees, and employee participation in policy formulation to enhance new culture. In addition, these opositions will enhance the corporate identity, brand, as well as university performance, product quality, policy and processes to enrich the corporate reputation during transformation. The findings challenge university management to actively engage the corporate communication function, emphasise employee participation, and focus on the continual improvement of corporate identity and reputation management practices for competitive advantage. The current study proposes a participative, multi-layered and multi-dimensional communication model for efficient and excellent internal communication. The current study recommends that corporate communication practitioner be strategically positioned to coordinate employee engagement, utilise appropriate communication channels and counsel university management on corporate identity, image and reputation management during organisational transformation.
- Full Text:
- Date Issued: 2020
Mechanism of action of non-synonymous single nucleotide variations associated with α-carbonic anhydrases II, IV and VIII
- Authors: Sanyanga, T. Allan
- Date: 2020
- Subjects: Carbonic anhydrase , Carbonic anhydrase -- Therapeutic use , Nucleotides
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167346 , vital:41470
- Description: The carbonic anhydrase (CA) group of enzymes are Zinc (Zn2+) metalloproteins responsible for the reversible hydration of CO2 to bicarbonate (BCT or HCO− 3 ) and protons (H+) for the facilitation of acid-base balance and homeostasis within the body. Across all organisms, a minimum of six CA families exist, including, α (alpha), β (beta), γ (gamma), δ (delta), η (eta) and ζ (zeta). Some organisms can have more than one family, with exception to humans that contain the α family solely. The α-CA family comprises of 16 isoforms (CA-I to CA-XV) including the CA-VIII, CA-X and CA-XI acatalytic isoforms. Of the catalytic isoforms, CA-II and CA-IV possess one of the fastest rates of reaction, and any disturbances to the function of these enzymes results in CA deficiencies and undesirable phenotypes. CA-II deficiencies result in osteopetrosis with renal tubular acidosis and cerebral calcification, whereas CA-IV deficiencies result in retinitis pigmentosa 17 (RP17). Phenotypic effects generally manifest as a result of poor protein folding and function due to the presence of non-synonymous single nucleotide variations (nsSNVs). Even within the acatalytic isoforms such as CA-VIII that llosterically regulates the affinity of inositol triphosphate (IP3) for the IP3 receptor type 1 (ITPR1) and regulates calcium (Ca2+) signalling, the presence of SNVs also causes phenotypes cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ3). Currently the majority of research into the CAs is focused on the inhibition of these proteins to achieve therapeutic effects in patients via the control of HCO− production or reabsorption as observed in glaucoma and diuretic medications. Little research has therefore been devoted into the identification of stabilising or activating compound that could rescue protein function in the case of deficiencies. The main aim of this research was to identify and characterise the effects of nsSNVs on the structure and function of CA-II, CA-IV and CA-VIII to set a foundation for rare disease studies into the CA group of proteins. Combined bioinformatics approaches divided into four main objectives were implemented. These included variant identification, sequence analysis and protein characterisation, force field (FF) parameter generation, molecular dynamics (MD) simulation and dynamic residue network analysis (DRN). Six variants for each of the CA-II, CA-IV and CA-VIII proteins with pathogenic annotations were identified from the HUMA and Ensembl databases. These included the pathogenic variants K18E, K18Q, H107Y, P236H, P236R and N252D for CA-II. CA-IV included the pathogenic R69H, R219C and R219S, and benign N86K, N177K and V234I variants. CA-VIII included pathogenic S100A, S100P, G162R and R237Q, and benign S100L and E109D variants. CA-II has been more extensively studied than CA-IV and CA-VIII, therefore residues essential to its function and stability are known. To discover important residues and regions within the CA-IV and CA-VIII proteins sequence and motif analysis was performed across the α-CA family, using CA-II as a reference. Sequence analysis identified multiple conserved residues between the two acatalytic CA-II and CA-IV, and the acatalytic CA-VIII isoforms that were proposed to be essential for protein stability. With exception to the benign N86K CA-IV variant, none of the other pathogenic or benign CA-II, CA-IV and CA-VIII SNVs were located at functionally or structurally important residues. Motif analysis identified 11 conserved and important motifs within the α-CA family. Several of the identified variants were located on these motifs including K18E, K18Q, H107Y and N252D (CA-II); N86K, R219C, R219S and V234I (CA-IV); and E109D, G162R and R237Q (CA-VIII). As there were no x-ray crystal structures of the variant proteins, homology modelling was performed to calculate the protein structures for characterisation. In CA-VIII, the substitution of Ser for Pro at position 100 (variant S100P) resulted in destruction of the β-sheet that the SNV was located on. Little is known about the mechanism of interaction between CA-VIII and ITPR1, and residues involved. SiteMap and CPORT were used to identify binding site amino for CA-VIII and results identified 38 potential residues. Traditional FFs are incapable of performing MD simulations of metalloproteins. The AMBER ff14SB FF was extended and Zn2+ FF parameters calculated to add support for metalloprotein MD simulations. In the protein, Zn2+ was noted to have a charge less than +1. Variant effects on protein structure were then investigated using MD simulations. Root mean square deviation (RMSD) and radius of gyration (Rg) results indicated subtle SNV effects to the variant global structure in CA-II and CA-IV. However, with regards to CA-VIII RMSD analysis highlighted that variant presence was associated with increases to the structural rigidity of the protein. Principal component analysis (PCA) in conjunction with free energy analysis was performed to observe variant effects on protein conformational sampling in 3D space. The binding of BCT to CA-II induced greater protein conformational sampling and was associated with higher free energy. In CA-IV and CA-VIII PCA analysis revealed key differences in the mechanism of action of pathogenic and benign SNVs. In CA-IV, wild-type (WT) and benign variant protein structures clustered into single low energy well hinting at the presence of more stable structures. Pathogenic variants were associated with higher free energy and proteins sampled more conformations without settling into a low energy well. PCA analysis of CA-VIII indicated the opposite to CA-IV. Pathogenic variants were clustered into low energy wells, while the WT and benign variants showed greater conformational sampling. Dynamic cross correlation (DCC) analysis was performed using the MD-TASK suite to determine variant effects on residue movement. CA-II WT protein revealed that BCT and CO2 were associated with anti-correlated and correlated residue movement, highlighting at opposite mechanisms. In CA-IV and CA-VIII variant presence resulted in a change to residue correlation compared to the WT proteins. DRN analysis was performed to investigate SNV effects of residue accessibility and communication. Results demonstrated that SNVs are associated with allosteric effects on the CA protein structures, and effects are located on the stability assisting residues of the aromatic clusters and the active site of the proteins. CA-II studies discovered that Glu117 is the most important residue for communication, and variant presence results in a decrease to the usage of the residue. This effect was greatest in the CA-II H107Y SNV, and suggests that variants could have an effect on Zn2+ dissociation from the active site. Decreases to the usage of Zn2+ coordinating residues were also noted. Where this occurred, compensatory increases to the usage of other primary and secondary coordination residues were observed, that could possibly assist with the maintenance of Zn2+ within the active site. The CA-IV variants R69H and R219C highlighted potentially similar pathogenic mechanisms, whereas N86K and N177K hinted at potentially similar benign mechanisms. Within CA-VIII, variant presence was associated with changes to the accessibility of the N-terminal binding site residues. The benign CA-VIII variants highlighted possible compensatory mechanisms, whereby as one group of N-terminal residues loses accessibility, there was an increase to the accessibility of other binding site residues to possibly balance the effect. Catalytically, the proton shuttle residue His64 in CA-II was found to occupy a novel conformation named the “faux in” that brought the imidazole group even closer to the Zn2+ compared to the “in” conformation. Overall, compared to traditional MD simulations the incorporation of DRN allowed more detailed investigations into the variant mechanisms of action. This highlights the importance of network analysis in the study of the effects of missense mutations on the structure and function of proteins. Investigations of diseases at the molecular level is essential in the identification of disease pathogenesis and assists with the development of specifically tailored and better treatment options especially in the cases of genetically associated rare diseases.
- Full Text:
- Date Issued: 2020
- Authors: Sanyanga, T. Allan
- Date: 2020
- Subjects: Carbonic anhydrase , Carbonic anhydrase -- Therapeutic use , Nucleotides
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167346 , vital:41470
- Description: The carbonic anhydrase (CA) group of enzymes are Zinc (Zn2+) metalloproteins responsible for the reversible hydration of CO2 to bicarbonate (BCT or HCO− 3 ) and protons (H+) for the facilitation of acid-base balance and homeostasis within the body. Across all organisms, a minimum of six CA families exist, including, α (alpha), β (beta), γ (gamma), δ (delta), η (eta) and ζ (zeta). Some organisms can have more than one family, with exception to humans that contain the α family solely. The α-CA family comprises of 16 isoforms (CA-I to CA-XV) including the CA-VIII, CA-X and CA-XI acatalytic isoforms. Of the catalytic isoforms, CA-II and CA-IV possess one of the fastest rates of reaction, and any disturbances to the function of these enzymes results in CA deficiencies and undesirable phenotypes. CA-II deficiencies result in osteopetrosis with renal tubular acidosis and cerebral calcification, whereas CA-IV deficiencies result in retinitis pigmentosa 17 (RP17). Phenotypic effects generally manifest as a result of poor protein folding and function due to the presence of non-synonymous single nucleotide variations (nsSNVs). Even within the acatalytic isoforms such as CA-VIII that llosterically regulates the affinity of inositol triphosphate (IP3) for the IP3 receptor type 1 (ITPR1) and regulates calcium (Ca2+) signalling, the presence of SNVs also causes phenotypes cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ3). Currently the majority of research into the CAs is focused on the inhibition of these proteins to achieve therapeutic effects in patients via the control of HCO− production or reabsorption as observed in glaucoma and diuretic medications. Little research has therefore been devoted into the identification of stabilising or activating compound that could rescue protein function in the case of deficiencies. The main aim of this research was to identify and characterise the effects of nsSNVs on the structure and function of CA-II, CA-IV and CA-VIII to set a foundation for rare disease studies into the CA group of proteins. Combined bioinformatics approaches divided into four main objectives were implemented. These included variant identification, sequence analysis and protein characterisation, force field (FF) parameter generation, molecular dynamics (MD) simulation and dynamic residue network analysis (DRN). Six variants for each of the CA-II, CA-IV and CA-VIII proteins with pathogenic annotations were identified from the HUMA and Ensembl databases. These included the pathogenic variants K18E, K18Q, H107Y, P236H, P236R and N252D for CA-II. CA-IV included the pathogenic R69H, R219C and R219S, and benign N86K, N177K and V234I variants. CA-VIII included pathogenic S100A, S100P, G162R and R237Q, and benign S100L and E109D variants. CA-II has been more extensively studied than CA-IV and CA-VIII, therefore residues essential to its function and stability are known. To discover important residues and regions within the CA-IV and CA-VIII proteins sequence and motif analysis was performed across the α-CA family, using CA-II as a reference. Sequence analysis identified multiple conserved residues between the two acatalytic CA-II and CA-IV, and the acatalytic CA-VIII isoforms that were proposed to be essential for protein stability. With exception to the benign N86K CA-IV variant, none of the other pathogenic or benign CA-II, CA-IV and CA-VIII SNVs were located at functionally or structurally important residues. Motif analysis identified 11 conserved and important motifs within the α-CA family. Several of the identified variants were located on these motifs including K18E, K18Q, H107Y and N252D (CA-II); N86K, R219C, R219S and V234I (CA-IV); and E109D, G162R and R237Q (CA-VIII). As there were no x-ray crystal structures of the variant proteins, homology modelling was performed to calculate the protein structures for characterisation. In CA-VIII, the substitution of Ser for Pro at position 100 (variant S100P) resulted in destruction of the β-sheet that the SNV was located on. Little is known about the mechanism of interaction between CA-VIII and ITPR1, and residues involved. SiteMap and CPORT were used to identify binding site amino for CA-VIII and results identified 38 potential residues. Traditional FFs are incapable of performing MD simulations of metalloproteins. The AMBER ff14SB FF was extended and Zn2+ FF parameters calculated to add support for metalloprotein MD simulations. In the protein, Zn2+ was noted to have a charge less than +1. Variant effects on protein structure were then investigated using MD simulations. Root mean square deviation (RMSD) and radius of gyration (Rg) results indicated subtle SNV effects to the variant global structure in CA-II and CA-IV. However, with regards to CA-VIII RMSD analysis highlighted that variant presence was associated with increases to the structural rigidity of the protein. Principal component analysis (PCA) in conjunction with free energy analysis was performed to observe variant effects on protein conformational sampling in 3D space. The binding of BCT to CA-II induced greater protein conformational sampling and was associated with higher free energy. In CA-IV and CA-VIII PCA analysis revealed key differences in the mechanism of action of pathogenic and benign SNVs. In CA-IV, wild-type (WT) and benign variant protein structures clustered into single low energy well hinting at the presence of more stable structures. Pathogenic variants were associated with higher free energy and proteins sampled more conformations without settling into a low energy well. PCA analysis of CA-VIII indicated the opposite to CA-IV. Pathogenic variants were clustered into low energy wells, while the WT and benign variants showed greater conformational sampling. Dynamic cross correlation (DCC) analysis was performed using the MD-TASK suite to determine variant effects on residue movement. CA-II WT protein revealed that BCT and CO2 were associated with anti-correlated and correlated residue movement, highlighting at opposite mechanisms. In CA-IV and CA-VIII variant presence resulted in a change to residue correlation compared to the WT proteins. DRN analysis was performed to investigate SNV effects of residue accessibility and communication. Results demonstrated that SNVs are associated with allosteric effects on the CA protein structures, and effects are located on the stability assisting residues of the aromatic clusters and the active site of the proteins. CA-II studies discovered that Glu117 is the most important residue for communication, and variant presence results in a decrease to the usage of the residue. This effect was greatest in the CA-II H107Y SNV, and suggests that variants could have an effect on Zn2+ dissociation from the active site. Decreases to the usage of Zn2+ coordinating residues were also noted. Where this occurred, compensatory increases to the usage of other primary and secondary coordination residues were observed, that could possibly assist with the maintenance of Zn2+ within the active site. The CA-IV variants R69H and R219C highlighted potentially similar pathogenic mechanisms, whereas N86K and N177K hinted at potentially similar benign mechanisms. Within CA-VIII, variant presence was associated with changes to the accessibility of the N-terminal binding site residues. The benign CA-VIII variants highlighted possible compensatory mechanisms, whereby as one group of N-terminal residues loses accessibility, there was an increase to the accessibility of other binding site residues to possibly balance the effect. Catalytically, the proton shuttle residue His64 in CA-II was found to occupy a novel conformation named the “faux in” that brought the imidazole group even closer to the Zn2+ compared to the “in” conformation. Overall, compared to traditional MD simulations the incorporation of DRN allowed more detailed investigations into the variant mechanisms of action. This highlights the importance of network analysis in the study of the effects of missense mutations on the structure and function of proteins. Investigations of diseases at the molecular level is essential in the identification of disease pathogenesis and assists with the development of specifically tailored and better treatment options especially in the cases of genetically associated rare diseases.
- Full Text:
- Date Issued: 2020
Mechatronics based highspeed rotational piezo actuator
- Authors: Raffler, Oliver
- Date: 2020
- Subjects: Piezoelectric materials , Piezoelectric devices Mechatronics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/${Handle} , vital:39811
- Description: The aim of this thesis is the development of a novel mechatronics-based high speed piezo actuator for rotational and linear motion. Mainly, the thesis deals with the development of a system for mechanical coupling of any number of piezostacks. This mechanical coupling allows the actuator to achieve a significantly increased deflection compared to current approaches. The developed concept offers the possibility of a linear or rotary motion. It is also possible to combine the two types of movement. In the first step, in order to gain a better understanding of the topic, the piezo technology and especially the existing piezo actuators and -motors are examined. Currently, the force generated by the piezo actuators is mainly transmitted by friction. The only exception is the PAD-Actuator, which transmits force by means of form locking. The concept developed here also transmits its force by means of form locking and, in addition to that, offers a novel and unique drive concept in the field of piezo actuators. In the course of this thesis a new concept for the mechanical coupling of piezo actuators was developed, simulated and subsequently manufactured. Thus the system could be examined under real conditions. The investigations carried out mainly dealt with quasi-static and dynamic investigations. In addition to that, the emission of the airborne and structure-borne noise of the system was analysed.
- Full Text:
- Date Issued: 2020
- Authors: Raffler, Oliver
- Date: 2020
- Subjects: Piezoelectric materials , Piezoelectric devices Mechatronics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/${Handle} , vital:39811
- Description: The aim of this thesis is the development of a novel mechatronics-based high speed piezo actuator for rotational and linear motion. Mainly, the thesis deals with the development of a system for mechanical coupling of any number of piezostacks. This mechanical coupling allows the actuator to achieve a significantly increased deflection compared to current approaches. The developed concept offers the possibility of a linear or rotary motion. It is also possible to combine the two types of movement. In the first step, in order to gain a better understanding of the topic, the piezo technology and especially the existing piezo actuators and -motors are examined. Currently, the force generated by the piezo actuators is mainly transmitted by friction. The only exception is the PAD-Actuator, which transmits force by means of form locking. The concept developed here also transmits its force by means of form locking and, in addition to that, offers a novel and unique drive concept in the field of piezo actuators. In the course of this thesis a new concept for the mechanical coupling of piezo actuators was developed, simulated and subsequently manufactured. Thus the system could be examined under real conditions. The investigations carried out mainly dealt with quasi-static and dynamic investigations. In addition to that, the emission of the airborne and structure-borne noise of the system was analysed.
- Full Text:
- Date Issued: 2020
Microbial fuel cells for remediation of metal rich wastewater coupled with bioelectricity generation
- Authors: Mshoperi, Edith
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/124112 , vital:35540
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2020
Microbial fuel cells for remediation of metal rich wastewater coupled with bioelectricity generation
- Authors: Mshoperi, Edith
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/124112 , vital:35540
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2020
Mineral Resources Governance and Socio-Economic Development in Zimbabwe
- Authors: Chawatama, Chrispen Tauya
- Date: 2020
- Subjects: Mines and mineral resources -- Zimbabwe Mining law --Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD(Dev)
- Identifier: http://hdl.handle.net/${Handle} , vital:42996
- Description: This study focused on investigating mineral resources governance (reflected in terms of three indicators of transparency, accountability and stakeholder inclusion) and its effect on socioeconomic development (in terms of three indicators of education, health and household incomes. Mineral resources can be a blessing and can lead to socioeconomic transformation of a country if they are managed transparently, accountably, inclusively equitably and sustainably. On the other hand, these subsoil capital assets can be a ‘curse’ and lead to poverty, conflicts amongst interest groups, elite capture, corruption and economic stagnation if they are not properly managed. Good governance of mineral resources seeks to ensure that the harnessing of mineral resources benefits the economy, enhances the quality of life and reduces poverty amongst citizens. The mining sector of Zimbabwe has risen to be the key economic sector in terms of its contribution to the GDP, FDI, fiscal revenue, exports and employment creation, particularly after the discovery of diamonds and more gold deposits in the country. However, in spite of the growth of the mining sector and its elevation to the mainstay of the economy, glaring dire socioeconomic conditions in terms of unemployment and high poverty levels, poor health, education and household incomes, leads one to question the way the country’s opulent mineral resources are being governed. The study used a mixed methods approach, through use of primary data (quantitative and qualitative data) and secondary data (archival data) as the basis for the collection as well as analysis of data. Complementarity of the research methods was achieved through use of data from household survey with 160 households in Mhondoro-Ngezi, Chegutu, Kwekwe and Shurugwi and in-depth interviews with officials of government ministries; of Finance and Economic Development, Health and Childcare, Primary and viii Secondary Education, local councillors, CSOs; ZELA and ZIMCODD, Traditional chiefs and ZASMC. The study established that mining growth is contributing somewhat to socio-economic development through employment creation, corporate social responsibility, CSOTs, ESPOs, taxation and royalties, but broad-based development has not taken place in the four districts. The study proposes a holistic mineral resources governance and socioeconomic development framework. The study recommends the Repeal of MMA and gazetting of a more comprehensive legal framework, implementation of constitutional provisions on transparency, accountability and stakeholder inclusion, adoption of free online tools for mineral processes disclosure, consolidation of the mining fiscal regime and so on.
- Full Text:
- Date Issued: 2020
- Authors: Chawatama, Chrispen Tauya
- Date: 2020
- Subjects: Mines and mineral resources -- Zimbabwe Mining law --Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD(Dev)
- Identifier: http://hdl.handle.net/${Handle} , vital:42996
- Description: This study focused on investigating mineral resources governance (reflected in terms of three indicators of transparency, accountability and stakeholder inclusion) and its effect on socioeconomic development (in terms of three indicators of education, health and household incomes. Mineral resources can be a blessing and can lead to socioeconomic transformation of a country if they are managed transparently, accountably, inclusively equitably and sustainably. On the other hand, these subsoil capital assets can be a ‘curse’ and lead to poverty, conflicts amongst interest groups, elite capture, corruption and economic stagnation if they are not properly managed. Good governance of mineral resources seeks to ensure that the harnessing of mineral resources benefits the economy, enhances the quality of life and reduces poverty amongst citizens. The mining sector of Zimbabwe has risen to be the key economic sector in terms of its contribution to the GDP, FDI, fiscal revenue, exports and employment creation, particularly after the discovery of diamonds and more gold deposits in the country. However, in spite of the growth of the mining sector and its elevation to the mainstay of the economy, glaring dire socioeconomic conditions in terms of unemployment and high poverty levels, poor health, education and household incomes, leads one to question the way the country’s opulent mineral resources are being governed. The study used a mixed methods approach, through use of primary data (quantitative and qualitative data) and secondary data (archival data) as the basis for the collection as well as analysis of data. Complementarity of the research methods was achieved through use of data from household survey with 160 households in Mhondoro-Ngezi, Chegutu, Kwekwe and Shurugwi and in-depth interviews with officials of government ministries; of Finance and Economic Development, Health and Childcare, Primary and viii Secondary Education, local councillors, CSOs; ZELA and ZIMCODD, Traditional chiefs and ZASMC. The study established that mining growth is contributing somewhat to socio-economic development through employment creation, corporate social responsibility, CSOTs, ESPOs, taxation and royalties, but broad-based development has not taken place in the four districts. The study proposes a holistic mineral resources governance and socioeconomic development framework. The study recommends the Repeal of MMA and gazetting of a more comprehensive legal framework, implementation of constitutional provisions on transparency, accountability and stakeholder inclusion, adoption of free online tools for mineral processes disclosure, consolidation of the mining fiscal regime and so on.
- Full Text:
- Date Issued: 2020
Modelling and investigating primary beam effects of reflector antenna arrays
- Authors: Iheanetu, Kelachukwu
- Date: 2020
- Subjects: Antennas, Reflector , Radio telescopes , Astronomical instruments -- Calibration , Holography , Polynomials , Very large array telescopes -- South Africa , Astronomy -- Data processing , Primary beam effects , Jacobi-Bessel pattern , Cassbeam software , MeerKAT telescope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147425 , vital:38635
- Description: Signals received by a radio telescope are always affected by propagation and instrumental effects. These effects need to be modelled and accounted for during the process of calibration. The primary beam (PB) of the antenna is one major instrumental effect that needs to be accounted for during calibration. Producing accurate models of the radio antenna PB is crucial, and many approaches (like electromagnetic and optical simulations) have been used to model it. The cos³ function, Jacobi-Bessel pattern, characteristic basis function patterns (CBFP) and Cassbeam software (which uses optical ray-tracing with antenna parameters) have also been used to model it. These models capture the basic PB effects. Real-life PB patterns differ from these models due to various subtle effects such as mechanical deformation and effects introduced into the PB due to standing waves that exist in reflector antennas. The actual patterns can be measured via a process called astro-holography (or holography), but this is subject to noise, radio frequency interference, and other measurement errors. In our approach, we use principal component analysis and Zernike polynomials to model the PBs of the Very Large Array (VLA) and the MeerKAT telescopes from their holography measured data. The models have reconstruction errors of less than 5% at a compression factor of approximately 98% for both arrays. We also present steps that can be used to generate accurate beam models for any telescope (independent of its design) based on holography measured data. Analysis of the VLA measured PBs revealed that the graph of the beam sizes (and centre offset positions) have a fast oscillating trend (superimposed on a slow trend) with frequency. This spectral behaviour we termed ripple or characteristic effects. Most existing PB models that are used in calibrating VLA data do not incorporate these direction dependent effects (DDEs). We investigate the impact of using PB models that ignore this DDE in continuum calibration and imaging via simulations. Our experiments show that, although these effects translate into less than 10% errors in source flux recovery, they do lead to 30% reduction in the dynamic range. To prepare data for Hi and radio halo (faint emissions) science analysis requires carrying out foreground subtraction of bright (continuum) sources. We investigate the impact of using beam models that ignore these ripple effects during continuum subtraction. These show that using PB models which completely ignore the ripple effects in continuum subtraction could translate to error of more to 30% in the recovered Hi spectral properties. This implies that science inferences drawn from the results for Hi studies could have errors of the same magnitude.
- Full Text:
- Date Issued: 2020
- Authors: Iheanetu, Kelachukwu
- Date: 2020
- Subjects: Antennas, Reflector , Radio telescopes , Astronomical instruments -- Calibration , Holography , Polynomials , Very large array telescopes -- South Africa , Astronomy -- Data processing , Primary beam effects , Jacobi-Bessel pattern , Cassbeam software , MeerKAT telescope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147425 , vital:38635
- Description: Signals received by a radio telescope are always affected by propagation and instrumental effects. These effects need to be modelled and accounted for during the process of calibration. The primary beam (PB) of the antenna is one major instrumental effect that needs to be accounted for during calibration. Producing accurate models of the radio antenna PB is crucial, and many approaches (like electromagnetic and optical simulations) have been used to model it. The cos³ function, Jacobi-Bessel pattern, characteristic basis function patterns (CBFP) and Cassbeam software (which uses optical ray-tracing with antenna parameters) have also been used to model it. These models capture the basic PB effects. Real-life PB patterns differ from these models due to various subtle effects such as mechanical deformation and effects introduced into the PB due to standing waves that exist in reflector antennas. The actual patterns can be measured via a process called astro-holography (or holography), but this is subject to noise, radio frequency interference, and other measurement errors. In our approach, we use principal component analysis and Zernike polynomials to model the PBs of the Very Large Array (VLA) and the MeerKAT telescopes from their holography measured data. The models have reconstruction errors of less than 5% at a compression factor of approximately 98% for both arrays. We also present steps that can be used to generate accurate beam models for any telescope (independent of its design) based on holography measured data. Analysis of the VLA measured PBs revealed that the graph of the beam sizes (and centre offset positions) have a fast oscillating trend (superimposed on a slow trend) with frequency. This spectral behaviour we termed ripple or characteristic effects. Most existing PB models that are used in calibrating VLA data do not incorporate these direction dependent effects (DDEs). We investigate the impact of using PB models that ignore this DDE in continuum calibration and imaging via simulations. Our experiments show that, although these effects translate into less than 10% errors in source flux recovery, they do lead to 30% reduction in the dynamic range. To prepare data for Hi and radio halo (faint emissions) science analysis requires carrying out foreground subtraction of bright (continuum) sources. We investigate the impact of using beam models that ignore these ripple effects during continuum subtraction. These show that using PB models which completely ignore the ripple effects in continuum subtraction could translate to error of more to 30% in the recovered Hi spectral properties. This implies that science inferences drawn from the results for Hi studies could have errors of the same magnitude.
- Full Text:
- Date Issued: 2020