Extreme value theory with applications in finance
- Authors: Matshaya, Aphelele
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465047 , vital:76568
- Description: The development and implementation of extreme value theory models has been very significant as they demonstrate an application of statistics that is very much needed in the analysis of extreme events in a wide range of industries, and more recently the cryptocurrency industry. The crypto industry is booming as the phenomenon of cryptocurrencies is spreading worldwide and constantly drawing the attention of investors, the media, as well as financial institutions. Cryptocurrencies are highly volatile assets whose price fluctuations continually lead to the loss of millions in a variety of currencies in the market. In this thesis, the extreme behaviour in the tail of the distribution of returns of Bitcoin will be examined. High-frequency Bitcoin data spanning periods before as well as after the COVID-19 pandemic will be utilised. The Peaks-over-Threshold method will be used to build models based on the generalised Pareto distribution, and both positive returns and negative returns will be modelled. Several techniques to select appropriate thresholds for the models are explored and the goodness-offit of the models assessed to determine the extent to which extreme value theory can model Bitcoin returns sufficiently. The analysis is extended and performed on Bitcoin data from a different crypto exchange to ensure model robustness is achieved. Using Bivariate extreme value theory, a Gumbel copula is fitted by the method of maximum likelihood with censored data to model the dynamic relationship between Bitcoin returns and trading volumes at the extreme tails. The extreme dependence and correlation structures will be analysed using tail dependence coefficients and the related extreme correlation coefficients. All computations are executed in R and the results are recorded in tabular and graphical formats. Tail-related measures of risk, namely Value-at-Risk and Expected Shortfall, are estimated from the extreme value models. Backtesting procedures are performed on the results from the risk models. A comparison between the negative returns of Bitcoin and those of Gold is carried out to determine which is the less risky asset to invest in during extreme market conditions. Extreme risk is calculated using the same extreme value approach and the results show that Bitcoin is riskier than Gold. , Thesis (MSc) -- Faculty of Science, Statistics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Matshaya, Aphelele
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465047 , vital:76568
- Description: The development and implementation of extreme value theory models has been very significant as they demonstrate an application of statistics that is very much needed in the analysis of extreme events in a wide range of industries, and more recently the cryptocurrency industry. The crypto industry is booming as the phenomenon of cryptocurrencies is spreading worldwide and constantly drawing the attention of investors, the media, as well as financial institutions. Cryptocurrencies are highly volatile assets whose price fluctuations continually lead to the loss of millions in a variety of currencies in the market. In this thesis, the extreme behaviour in the tail of the distribution of returns of Bitcoin will be examined. High-frequency Bitcoin data spanning periods before as well as after the COVID-19 pandemic will be utilised. The Peaks-over-Threshold method will be used to build models based on the generalised Pareto distribution, and both positive returns and negative returns will be modelled. Several techniques to select appropriate thresholds for the models are explored and the goodness-offit of the models assessed to determine the extent to which extreme value theory can model Bitcoin returns sufficiently. The analysis is extended and performed on Bitcoin data from a different crypto exchange to ensure model robustness is achieved. Using Bivariate extreme value theory, a Gumbel copula is fitted by the method of maximum likelihood with censored data to model the dynamic relationship between Bitcoin returns and trading volumes at the extreme tails. The extreme dependence and correlation structures will be analysed using tail dependence coefficients and the related extreme correlation coefficients. All computations are executed in R and the results are recorded in tabular and graphical formats. Tail-related measures of risk, namely Value-at-Risk and Expected Shortfall, are estimated from the extreme value models. Backtesting procedures are performed on the results from the risk models. A comparison between the negative returns of Bitcoin and those of Gold is carried out to determine which is the less risky asset to invest in during extreme market conditions. Extreme risk is calculated using the same extreme value approach and the results show that Bitcoin is riskier than Gold. , Thesis (MSc) -- Faculty of Science, Statistics, 2024
- Full Text:
- Date Issued: 2024-10-11
Figuring the black femme fatale: analysing black womanhood in U-Carmen eKhayelitsha
- Authors: Waters-Maine, Leigh
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466117 , vital:76687
- Description: In this thesis, I investigate black womanhood in U-Carmen eKhayelitsha, a post-apartheid film opera. The aim of this research is to examine the representation of black women in this film opera, focusing largely on the lead character, U-Carmen. This thesis is driven by a form of intersectional feminism which is characterised by overlapping categories such as race, gender, class and sexual orientation (Crenshaw 1989). A growing number of scholars have written about the rise of South African operas (Roos 2012; André 2016; Gerber 2021) but have seldom focused on the multi-layered representation of black women, which is what this thesis aims to do. In reading this work, I argue that U-Carmen eKhayelitsa foregrounds U-Carmen as a black woman with a storyline that rejects essentialists portrayals of black women on opera stages. The film opera, I argue, figures a complex womanhood represented in voice, labour, motherhood, and death. It not only recognizes the marginalised, but it also offers a change to the perception of the gendering of the black female body. In this thesis, I employ textual analysis to consider the historical contexts of U-Carmen alongside its contemporary resonances and analyse the main female character in the opera and how she can enforce or change the narrative of the role of women in opera. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Waters-Maine, Leigh
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466117 , vital:76687
- Description: In this thesis, I investigate black womanhood in U-Carmen eKhayelitsha, a post-apartheid film opera. The aim of this research is to examine the representation of black women in this film opera, focusing largely on the lead character, U-Carmen. This thesis is driven by a form of intersectional feminism which is characterised by overlapping categories such as race, gender, class and sexual orientation (Crenshaw 1989). A growing number of scholars have written about the rise of South African operas (Roos 2012; André 2016; Gerber 2021) but have seldom focused on the multi-layered representation of black women, which is what this thesis aims to do. In reading this work, I argue that U-Carmen eKhayelitsa foregrounds U-Carmen as a black woman with a storyline that rejects essentialists portrayals of black women on opera stages. The film opera, I argue, figures a complex womanhood represented in voice, labour, motherhood, and death. It not only recognizes the marginalised, but it also offers a change to the perception of the gendering of the black female body. In this thesis, I employ textual analysis to consider the historical contexts of U-Carmen alongside its contemporary resonances and analyse the main female character in the opera and how she can enforce or change the narrative of the role of women in opera. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
Fishery characteristics, genetic structure, population demography and value chain of Skipjack and Kawakawa exploited in coastal waters of the Western Indian Ocean
- Authors: Mzingirwa, Fatuma Ali
- Date: 2024-10-11
- Subjects: Fisheries Indian Ocean Region , Single nucleotide polymorphisms , Marine fishes Spawning , Marine fishes Size , Sustainable fisheries , Value creation , Market structure
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466759 , vital:76776 , DOI https://doi.org/10.21504/10962/466759
- Description: Tuna represents a highly valuable global fishery, comprising 7.9% of the total 67.9 million metric tons (MT) of marine finfish catch. Among tuna species, Katsuwonus pelamis, skipjack and Euthynnus affinis, kawakawa are commercially important, particularly for artisanal fisheries. Skipjack is the most dominant tuna species globally, contributing over 60% to total tuna production. In the Indian Ocean (IO), skipjack catches approximately 420,000 MT annually. Kawakawa, the second most abundant neritic tuna in the IO, accounting for roughly 12% of neritic tuna landings, is primarily harvested by artisanal fleets, with annual catches of around 160,000 MT. While current assessments indicate that skipjack and kawakawa stocks in the IO are not overfished, maintaining their long-term health is crucial. This research addresses three key areas: genetic diversity, population structure, and connectivity of skipjack and kawakawa tuna in the Western Indian Ocean (WIO); size structure and reproductive characteristics of these species within the WIO; and the value chain of the Kenyan artisanal tuna fishery, focusing on skipjack and kawakawa. To achieve these objectives, skipjack and kawakawa samples were collected from Kenya, Tanzania, Mozambique, and South Africa. A non-random sampling approach was employed to obtain specimens and data from artisanal and recreational fisheries. Biological and genetic sampling were conducted concurrently. The economic value chain of the Kenyan artisanal tuna fishery was examined through questionnaires and catch data. This analysis focused on the socio-demographic profiles of key actors, the value chain structure, and associated economic benefits across four Kenyan landing sites. To investigate stock structure in WIO skipjack and kawakawa tuna, we employed tunable Genotyping-by-Sequencing (tGBS) to generate genome-wide Single Nucleotide Polymorphism (SNP) data. Skipjack analysis revealed 7005 SNPs with an average observed heterozygosity (Ho) of 0.206. While overall genetic differentiation (FST) among samples was low (global FST = 0.003) between samples (FST = 0 – 0.013), significant genetic differences were observed between skipjack samples taken north of Mtwara in southern Tanzania (i.e., northern Tanzania, Kenya and Sri Lanka) and those to the south (i.e., southern Tanzania, Mozambique and South Africa), with Seychelles falling closer to the southern grouping. Kawakawa analysis, based on 14806 SNPs and an average Ho of 0.2585, indicated a patchy distribution of low but significant genetic differentiation among WIO populations (global FST = 0.018) between-sample (FST = 0.003 – 0.036) but with no obvious geographically-based pattern. However, unlike skipjack, a clear geographic pattern in genetic structure was not evident for kawakawa. Skipjack and kawakawa populations in the WIO exhibited seasonal fluctuations in size distribution, potentially influenced by environmental conditions and fishing practices. Landings of both species were male-biased, with sex ratios of 58% and 53% for skipjack and kawakawa, respectively. Female skipjack reached sexual maturity at a fork length (FL) of 42.0 cm, while males matured at 47.0 cm FL. For kawakawa, female and male maturation lengths were 44.0 cm FL and 45.3 cm FL, respectively. Spawning occurred throughout the year, with peak activity coinciding with the Northeast Monsoon (NEM) season. Our analysis of the artisanal tuna value chain indicates that fishers primarily sell their catch to agents (53%), with the remaining proportions going to traders (20%) and processors (18%). Processors, predominantly women, play a key role in the value chain and realized the highest net profit margin (49.5%). Limited post-harvest infrastructure, inadequate transportation, and poor marketing conditions were identified as key challenges impacting the quality of fish lowering their income. These challenges disproportionately affect fishers with limited access to market information and financial resources. The findings demonstrate the need for multi-level interventions to optimize benefits from the artisanal tuna fishery along the entire value chain taking into consideration the economic, environmental, and social dimensions. This research provides crucial information for effective tuna management in the IO. Current management practices treat skipjack and kawakawa as a single, homogenous population across the entire IO. However, our genetic findings suggest the presence of distinct population groups (stocks) for both species within the WIO. Moreover, seasonal variations in size structure and reproductive characteristics observed support this hypothesis of multiple stocks. These results emphasize the need for a precautionary approach to tuna management in the region. Collaborative efforts among countries are essential to develop sustainable fisheries management strategies that consider biological, economic, and social factors. By integrating these perspectives, we can ensure the long-term health of tuna populations while supporting the livelihoods of fishing communities. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mzingirwa, Fatuma Ali
- Date: 2024-10-11
- Subjects: Fisheries Indian Ocean Region , Single nucleotide polymorphisms , Marine fishes Spawning , Marine fishes Size , Sustainable fisheries , Value creation , Market structure
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466759 , vital:76776 , DOI https://doi.org/10.21504/10962/466759
- Description: Tuna represents a highly valuable global fishery, comprising 7.9% of the total 67.9 million metric tons (MT) of marine finfish catch. Among tuna species, Katsuwonus pelamis, skipjack and Euthynnus affinis, kawakawa are commercially important, particularly for artisanal fisheries. Skipjack is the most dominant tuna species globally, contributing over 60% to total tuna production. In the Indian Ocean (IO), skipjack catches approximately 420,000 MT annually. Kawakawa, the second most abundant neritic tuna in the IO, accounting for roughly 12% of neritic tuna landings, is primarily harvested by artisanal fleets, with annual catches of around 160,000 MT. While current assessments indicate that skipjack and kawakawa stocks in the IO are not overfished, maintaining their long-term health is crucial. This research addresses three key areas: genetic diversity, population structure, and connectivity of skipjack and kawakawa tuna in the Western Indian Ocean (WIO); size structure and reproductive characteristics of these species within the WIO; and the value chain of the Kenyan artisanal tuna fishery, focusing on skipjack and kawakawa. To achieve these objectives, skipjack and kawakawa samples were collected from Kenya, Tanzania, Mozambique, and South Africa. A non-random sampling approach was employed to obtain specimens and data from artisanal and recreational fisheries. Biological and genetic sampling were conducted concurrently. The economic value chain of the Kenyan artisanal tuna fishery was examined through questionnaires and catch data. This analysis focused on the socio-demographic profiles of key actors, the value chain structure, and associated economic benefits across four Kenyan landing sites. To investigate stock structure in WIO skipjack and kawakawa tuna, we employed tunable Genotyping-by-Sequencing (tGBS) to generate genome-wide Single Nucleotide Polymorphism (SNP) data. Skipjack analysis revealed 7005 SNPs with an average observed heterozygosity (Ho) of 0.206. While overall genetic differentiation (FST) among samples was low (global FST = 0.003) between samples (FST = 0 – 0.013), significant genetic differences were observed between skipjack samples taken north of Mtwara in southern Tanzania (i.e., northern Tanzania, Kenya and Sri Lanka) and those to the south (i.e., southern Tanzania, Mozambique and South Africa), with Seychelles falling closer to the southern grouping. Kawakawa analysis, based on 14806 SNPs and an average Ho of 0.2585, indicated a patchy distribution of low but significant genetic differentiation among WIO populations (global FST = 0.018) between-sample (FST = 0.003 – 0.036) but with no obvious geographically-based pattern. However, unlike skipjack, a clear geographic pattern in genetic structure was not evident for kawakawa. Skipjack and kawakawa populations in the WIO exhibited seasonal fluctuations in size distribution, potentially influenced by environmental conditions and fishing practices. Landings of both species were male-biased, with sex ratios of 58% and 53% for skipjack and kawakawa, respectively. Female skipjack reached sexual maturity at a fork length (FL) of 42.0 cm, while males matured at 47.0 cm FL. For kawakawa, female and male maturation lengths were 44.0 cm FL and 45.3 cm FL, respectively. Spawning occurred throughout the year, with peak activity coinciding with the Northeast Monsoon (NEM) season. Our analysis of the artisanal tuna value chain indicates that fishers primarily sell their catch to agents (53%), with the remaining proportions going to traders (20%) and processors (18%). Processors, predominantly women, play a key role in the value chain and realized the highest net profit margin (49.5%). Limited post-harvest infrastructure, inadequate transportation, and poor marketing conditions were identified as key challenges impacting the quality of fish lowering their income. These challenges disproportionately affect fishers with limited access to market information and financial resources. The findings demonstrate the need for multi-level interventions to optimize benefits from the artisanal tuna fishery along the entire value chain taking into consideration the economic, environmental, and social dimensions. This research provides crucial information for effective tuna management in the IO. Current management practices treat skipjack and kawakawa as a single, homogenous population across the entire IO. However, our genetic findings suggest the presence of distinct population groups (stocks) for both species within the WIO. Moreover, seasonal variations in size structure and reproductive characteristics observed support this hypothesis of multiple stocks. These results emphasize the need for a precautionary approach to tuna management in the region. Collaborative efforts among countries are essential to develop sustainable fisheries management strategies that consider biological, economic, and social factors. By integrating these perspectives, we can ensure the long-term health of tuna populations while supporting the livelihoods of fishing communities. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Fluorescence-doped silica nanoparticles for ultrasensitive detection of prostate specific antigen
- Authors: Msutu, Tumelo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464543 , vital:76520
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Msutu, Tumelo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464543 , vital:76520
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Foreign aid mix and manufactured exports performance in sub-Saharan Africa
- Authors: Ndalama, Jewel Stebbins
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466361 , vital:76721 , DOI 10.21504/10962/466361
- Description: This study aims at finding out effects of foreign aid mix on manufactured exports performance in Sub-Saharan Africa. This is important as the region has lagged behind on promotion of manufactured exports thereby relying on primary exports. For a country’s exports to be competitive internationally, and hence improve economically, it has to manufacture products part of which can be exported. Sub-Saharan African countries have relied on primary exports which fetch low prices at international market thereby bringing in low foreign exchange. This is why African countries have relied on foreign aid since they cannot generate enough foreign exchange which is needed to import goods and services they cannot produce domestically. African countries have to boost manufactured exports which fetch high prices at international market hence they bring in the much-needed foreign exchange. Reliance on foreign aid may not be sustainable as donors have their own priorities and may not be able to give aid indefinitely. African countries have to find sustainable ways of generating foreign exchange one of which is to boost manufactured exports. As boosting manufactured exports in these countries requires resources, foreign aid can be used to improve manufacturing and manufactured exports. In this case, the countries can later stop relying on foreign aid. This study first examines the impact of foreign aid on terms of trade. Holding price of imports constant, improvement in terms of trade means that either prices of primary exports have increased or there has been improvement in manufactured exports which are known to fetch high prices at international market. The study then examines the impact of foreign aid on manufactured exports. Most of the studies have dwelt on the impact of foreign aid on exports. This study has gone further to assess the impact of foreign aid on one of the components of exports namely manufactured exports. Thereafter, the study examines the impact of disaggregated foreign aid on manufactured exports. While some studies have criticised foreign aid as having little or no impact on recipient country, it is necessary to disaggregate the aid by sector since aid to some sectors may have positive impact on those sectors, and other sectors of the economy. The study has also examined asymmetric effects of various types of foreign aid, that is, whether or not, positive and negative changes of each type of aid have the same impact on manufactured exports. The study uses both panel and pooled data for 30 Sub-Saharan African countries for the period from 1970 to 2019. Models used include Autoregressive Distributed Lag (ARDL), Non-linear Autoregressive Distributed Lag (NARDL), Generalised Least Squares (GLS), among other models. The study has found that foreign aid has a negative and statistically significant impact on terms of trade. This means that foreign aid does not improve export prices relative to those of imports in the Sub-Saharan African countries. According to Prebisch-Singer Dependency Theory, price of primary commodities declines relative to the price of manufactured goods, causing terms of trade of primary product-based economies to deteriorate. This study has shown that foreign aid deteriorates terms of trade thereby worsening the situation of African countries which mainly export primary commodities and import manufactured products. This calls for African economies to diversify their export base to include manufactured exports, otherwise, foreign aid, which is one of the main sources of resources for African economies will keep on worsening the countries’ terms of trade. Further, the study finds that foreign aid has negative impact on manufactured exports. Like other studies that have disputed the impact of foreign aid on economic growth, this study has also found that foreign aid does not have a positive impact on manufactured exports, one of the most important factors influencing economic growth in any country. This calls for policy reform on building manufacturing capabilities in the Sub-Saharan African countries. Effectiveness of foreign aid also depends on dynamics of a country as country specific results show varying effects of foreign aid on manufactured exports, with some countries experiencing positive impact and others negative impact. Donors should therefore be assessing whether in the prospective recipient country, foreign aid will have a positive impact on manufactured exports especially if their aim is to boost manufactured exports. Though total aid has a negative and statistically insignificant impact on manufactured exports, disaggregating it shows that other types of aid such as grants, agricultural aid and health aid have positive and statistically significant impacts. Thus, criticising foreign aid is not proper as some of its components have positive impact on manufactured exports. Therefore, allocating foreign aid to sectors that can impact positively on manufactured exports will go a long way in boosting manufactured exports in these countries. In addition to assessing recipient countries, donors should assess sectors in each country to find out sectors which if funded can boost manufactured exports. Country-specific results show different impacts of different types of aid with some types having positive impact, and others negative impact on manufactured exports. This means that the effectiveness of different types of foreign aid depends on a country. The study has also shown that there are no asymmetric effects of all types of aid meaning that there are no significant differences in impacts of positive or negative changes in the types of aid. Fixed capital (proxy for infrastructure development), foreign direct investment, and openness are found to be positively related to manufactured exports and statistically significant regardless of model used, and whether data used is pooled or panel. This calls for other ways of improving manufactured exports in the region. Improving infrastructure (fixed capital), attracting foreign direct investment, and opening up Sub-Saharan African countries can go a long way in promoting manufactured exports in the region. The study also ran regressions after including private sector credit, and excluding Zimbabwe, a country that faced economic challenges during the study period especially towards the end of the study period to the extent that macroeconomic fundamentals were far from being normal. However, results are not much different from results without private sector credit, and inclusion of Zimbabwe. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ndalama, Jewel Stebbins
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466361 , vital:76721 , DOI 10.21504/10962/466361
- Description: This study aims at finding out effects of foreign aid mix on manufactured exports performance in Sub-Saharan Africa. This is important as the region has lagged behind on promotion of manufactured exports thereby relying on primary exports. For a country’s exports to be competitive internationally, and hence improve economically, it has to manufacture products part of which can be exported. Sub-Saharan African countries have relied on primary exports which fetch low prices at international market thereby bringing in low foreign exchange. This is why African countries have relied on foreign aid since they cannot generate enough foreign exchange which is needed to import goods and services they cannot produce domestically. African countries have to boost manufactured exports which fetch high prices at international market hence they bring in the much-needed foreign exchange. Reliance on foreign aid may not be sustainable as donors have their own priorities and may not be able to give aid indefinitely. African countries have to find sustainable ways of generating foreign exchange one of which is to boost manufactured exports. As boosting manufactured exports in these countries requires resources, foreign aid can be used to improve manufacturing and manufactured exports. In this case, the countries can later stop relying on foreign aid. This study first examines the impact of foreign aid on terms of trade. Holding price of imports constant, improvement in terms of trade means that either prices of primary exports have increased or there has been improvement in manufactured exports which are known to fetch high prices at international market. The study then examines the impact of foreign aid on manufactured exports. Most of the studies have dwelt on the impact of foreign aid on exports. This study has gone further to assess the impact of foreign aid on one of the components of exports namely manufactured exports. Thereafter, the study examines the impact of disaggregated foreign aid on manufactured exports. While some studies have criticised foreign aid as having little or no impact on recipient country, it is necessary to disaggregate the aid by sector since aid to some sectors may have positive impact on those sectors, and other sectors of the economy. The study has also examined asymmetric effects of various types of foreign aid, that is, whether or not, positive and negative changes of each type of aid have the same impact on manufactured exports. The study uses both panel and pooled data for 30 Sub-Saharan African countries for the period from 1970 to 2019. Models used include Autoregressive Distributed Lag (ARDL), Non-linear Autoregressive Distributed Lag (NARDL), Generalised Least Squares (GLS), among other models. The study has found that foreign aid has a negative and statistically significant impact on terms of trade. This means that foreign aid does not improve export prices relative to those of imports in the Sub-Saharan African countries. According to Prebisch-Singer Dependency Theory, price of primary commodities declines relative to the price of manufactured goods, causing terms of trade of primary product-based economies to deteriorate. This study has shown that foreign aid deteriorates terms of trade thereby worsening the situation of African countries which mainly export primary commodities and import manufactured products. This calls for African economies to diversify their export base to include manufactured exports, otherwise, foreign aid, which is one of the main sources of resources for African economies will keep on worsening the countries’ terms of trade. Further, the study finds that foreign aid has negative impact on manufactured exports. Like other studies that have disputed the impact of foreign aid on economic growth, this study has also found that foreign aid does not have a positive impact on manufactured exports, one of the most important factors influencing economic growth in any country. This calls for policy reform on building manufacturing capabilities in the Sub-Saharan African countries. Effectiveness of foreign aid also depends on dynamics of a country as country specific results show varying effects of foreign aid on manufactured exports, with some countries experiencing positive impact and others negative impact. Donors should therefore be assessing whether in the prospective recipient country, foreign aid will have a positive impact on manufactured exports especially if their aim is to boost manufactured exports. Though total aid has a negative and statistically insignificant impact on manufactured exports, disaggregating it shows that other types of aid such as grants, agricultural aid and health aid have positive and statistically significant impacts. Thus, criticising foreign aid is not proper as some of its components have positive impact on manufactured exports. Therefore, allocating foreign aid to sectors that can impact positively on manufactured exports will go a long way in boosting manufactured exports in these countries. In addition to assessing recipient countries, donors should assess sectors in each country to find out sectors which if funded can boost manufactured exports. Country-specific results show different impacts of different types of aid with some types having positive impact, and others negative impact on manufactured exports. This means that the effectiveness of different types of foreign aid depends on a country. The study has also shown that there are no asymmetric effects of all types of aid meaning that there are no significant differences in impacts of positive or negative changes in the types of aid. Fixed capital (proxy for infrastructure development), foreign direct investment, and openness are found to be positively related to manufactured exports and statistically significant regardless of model used, and whether data used is pooled or panel. This calls for other ways of improving manufactured exports in the region. Improving infrastructure (fixed capital), attracting foreign direct investment, and opening up Sub-Saharan African countries can go a long way in promoting manufactured exports in the region. The study also ran regressions after including private sector credit, and excluding Zimbabwe, a country that faced economic challenges during the study period especially towards the end of the study period to the extent that macroeconomic fundamentals were far from being normal. However, results are not much different from results without private sector credit, and inclusion of Zimbabwe. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
Foundation phase teachers’ understanding and implementation of differentiated pedagogical practices in teaching reading
- Authors: Muroa, Johanna Makgati
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463713 , vital:76434
- Description: Pre-1994, teacher education in South Africa was separated into mainstream and special education classes. Special education classes accommodated learners who were not coping with grade-level work. In 2001, Education White Paper Six advocated for inclusive education. This policy promotes differentiated pedagogical practices to accommodate learners’ needs and minimize barriers to learning. However, research has shown that teachers do not have the required content and pedagogical knowledge to teach according to diverse learners’ needs. One of the reasons given is that the teacher education system does not prepare teachers adequately to teach in classrooms with diverse learners. This qualitative case study is underpinned by an interpretivist orientation as it seeks to ascertain how teachers understand and implement differentiated pedagogical tools in their practice. The research asks the question: How do Foundation Phase teachers understand and implement differentiated pedagogical tools? Seventy-six teachers enrolled for in-service Bachelor of Education (Foundation Phase) completed a questionnaire and three Foundation Phase teachers were observed and interviewed. Data gathered was analyzed using the Theory of Practice Architectures. The study found that the teachers recognized the importance of accommodating the different learners’ learning needs, however, they struggled to implement differentiated pedagogical practices in the classroom. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Muroa, Johanna Makgati
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463713 , vital:76434
- Description: Pre-1994, teacher education in South Africa was separated into mainstream and special education classes. Special education classes accommodated learners who were not coping with grade-level work. In 2001, Education White Paper Six advocated for inclusive education. This policy promotes differentiated pedagogical practices to accommodate learners’ needs and minimize barriers to learning. However, research has shown that teachers do not have the required content and pedagogical knowledge to teach according to diverse learners’ needs. One of the reasons given is that the teacher education system does not prepare teachers adequately to teach in classrooms with diverse learners. This qualitative case study is underpinned by an interpretivist orientation as it seeks to ascertain how teachers understand and implement differentiated pedagogical tools in their practice. The research asks the question: How do Foundation Phase teachers understand and implement differentiated pedagogical tools? Seventy-six teachers enrolled for in-service Bachelor of Education (Foundation Phase) completed a questionnaire and three Foundation Phase teachers were observed and interviewed. Data gathered was analyzed using the Theory of Practice Architectures. The study found that the teachers recognized the importance of accommodating the different learners’ learning needs, however, they struggled to implement differentiated pedagogical practices in the classroom. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Gold mineralization at the Blue Rock Deposit, Gadzema Greenstone Belt: Implications on genesis and exploration for orogenic gold mineralization within Archaean Greenstone Belts of Zimbabwe
- Authors: Mavuwa, Tavashavira
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464944 , vital:76559
- Description: The Blue Rock gold deposit was re-discovered by African Consolidated Resources (ACR) in 2007, over a defunct historical gold mine at Blue Rock, during a regional geochemical soil sampling program, within the Gadzema Greenstone Belt (GGB), in Central Zimbabwe. Most significant orogenic gold deposits within this belt occur as BIF- and quartz vein hosted orebodies. But unlike them, gold mineralization at Blue Rock is associated with felsite and quartz porphyry rocks. The GGB is a northern extension of the Midlands Greenstone Belt (MGB), where the common occurrence of mineralized felsites, in close association with major gold reefs within numerous gold mines is well documented. But no significant effort was directed towards their understanding or exploration in the past. They were never considered viable exploration targets for significant economic gold deposits, until recently. More attention was instead focused on high-grade BIF and quartz vein hosted gold, that dominate most orebodies exploited by numerous mines within the belt. At Blue Rock, ACR defined a significant JORC compliant felsite-hosted gold resource of close to a million ounces, which represents a brand new attractive open-pit mining opportunity. But the successful exploration for such type of mineralization, whose footprint is so different from the common ones previously mined within the GGB, no doubt, calls for a good understanding of this type of mineralization. Which makes felsite-hosted gold mineralization a prime candidate for research, based on a deposit whose discovery and development, I was fortunate to be part of during the past few years. In this contribution, the genesis, localization and economic significance of felsite-hosted gold mineralization is investigated, using the gold deposit at Blue Rock as a case study. The deposit could be understood best through the Mineral Systems Approach, used in this study to interrogate alternative ideas about its genesis using published information and deposit-scale exploratory data. Results from the synthesis of published information on the evolution of Archaean Greenstone Belts and genesis of their host orogenic gold deposits, are consistent with models that view orogenic terrains as having formed through horizontal accretion in modern-day like subduction-accretion systems, at continental margins, where orogenic gold deposition occurred via processes that could be explained quite simply, through a universal orogenic gold mineral systems model. According to this model, orogenic gold deposits are believed to have formed from near neutral fluids containing dissolved gold, generated directly from the devolatilization of a subducted oceanic slab together with its overlying gold-bearing sulphide-rich sedimentary package, or indirectly through fluid released from a mantle lithosphere that was originally metasomatized and fertilized during an earlier subduction event. The fluid migrated up-dip from the mantle to crustal levels, through advection or seismic pumping along lithosphere- to crustal-scale fault zones, to form orogenic gold deposits within lower order structures. If these models are all accurate, then the GGB formed through subduction-related east-directed horizontal accretion at the continental margins of the Sebakwe Proto-Craton (SPC), and the genesis of felsite-hosted gold mineralization at Blue Rock could be explained eloquently through a universal orogenic gold model, in which mantle derived auriferous fluids were localised within lower order structures associated with felsites during the late stages of terrain accretion. Evidence from surface mapping and 3D modelling of exploratory drilling data, conducted during this research, strongly support the argument that the felsite hosted gold mineralization at Blue Rock, is neither unique nor accidental. It is just but, a simple product of the conjunction of favourable geological factors, no different to those that birthed typical GGB orogenic gold mineralization hosted within sheared sulphidic BIFs and quartz vein reefs. They all share the same geodynamic setting, fertility, preservation and regional architectural factors reminiscent of accretionary orogenic settings, albeit with differences in local architecture, variably controlled by geochemical and rheological properties of the different local host rocks. At deposit scale, the felsites occur as small dykes and sills emplaced along pre-existing structural zones of weakness. Gold mineralization is structurally controlled and associated mostly with brittle-ductile shears. During deformation, rheological contrast played a significant role in the selective failure of the more competent felsite rocks, resulting in the creation of permeability channels that allowed fluid migration. The more brittle and competent felsites acted as rigid bodies, that localised strain along their contacts with the surrounding less competent ductile mafic schists which acted as a relatively less permeable fluid cap rock. The irregular felsite contact zones with surrounding mafic schist caused a significant variation in the orientation of local principal maximum stress relative to the internally imposed regional stress, causing anomalously low minimum stress zones at deposit scale. Gold deposition occurred within low minimum stress structural traps dominated by sheared felsite contacts and their fractured interiors as well as triple junctions formed by complex structural geometries created by multiple felsite intrusions. The felsite hosted gold at Blue Rock can therefore be recognized as an orogenic gold mineral system archetype, for which an occurrence model is proposed. Understanding this type of mineralization is key for developing a robust exploration strategy - one that could be applied in a predictive capacity in exploration, to locate new economic gold deposits especially within well-endowed mature orogenic terrains, where exploration risk could be minimized by leveraging on new forward-thinking initiatives like Artificial Intelligence (AI) to re-analyze data from previous mining and exploration, allowing for a faster route to a return on investment. In a world of diminishing natural resources, the potential for previously ignored gold mineralization like the one at Blue Rock, becomes very significant. The prophetic words of Foster (1984), writing in Gold ‘82, therefore remain true and relevant to our time, that; “…. the way ahead for successful gold exploration is to search for new deposits not commonly recognized – in auriferous muds, disseminations in carbonate rocks, porphyries, and in felsic intrusive and extrusive volcanics…”. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mavuwa, Tavashavira
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464944 , vital:76559
- Description: The Blue Rock gold deposit was re-discovered by African Consolidated Resources (ACR) in 2007, over a defunct historical gold mine at Blue Rock, during a regional geochemical soil sampling program, within the Gadzema Greenstone Belt (GGB), in Central Zimbabwe. Most significant orogenic gold deposits within this belt occur as BIF- and quartz vein hosted orebodies. But unlike them, gold mineralization at Blue Rock is associated with felsite and quartz porphyry rocks. The GGB is a northern extension of the Midlands Greenstone Belt (MGB), where the common occurrence of mineralized felsites, in close association with major gold reefs within numerous gold mines is well documented. But no significant effort was directed towards their understanding or exploration in the past. They were never considered viable exploration targets for significant economic gold deposits, until recently. More attention was instead focused on high-grade BIF and quartz vein hosted gold, that dominate most orebodies exploited by numerous mines within the belt. At Blue Rock, ACR defined a significant JORC compliant felsite-hosted gold resource of close to a million ounces, which represents a brand new attractive open-pit mining opportunity. But the successful exploration for such type of mineralization, whose footprint is so different from the common ones previously mined within the GGB, no doubt, calls for a good understanding of this type of mineralization. Which makes felsite-hosted gold mineralization a prime candidate for research, based on a deposit whose discovery and development, I was fortunate to be part of during the past few years. In this contribution, the genesis, localization and economic significance of felsite-hosted gold mineralization is investigated, using the gold deposit at Blue Rock as a case study. The deposit could be understood best through the Mineral Systems Approach, used in this study to interrogate alternative ideas about its genesis using published information and deposit-scale exploratory data. Results from the synthesis of published information on the evolution of Archaean Greenstone Belts and genesis of their host orogenic gold deposits, are consistent with models that view orogenic terrains as having formed through horizontal accretion in modern-day like subduction-accretion systems, at continental margins, where orogenic gold deposition occurred via processes that could be explained quite simply, through a universal orogenic gold mineral systems model. According to this model, orogenic gold deposits are believed to have formed from near neutral fluids containing dissolved gold, generated directly from the devolatilization of a subducted oceanic slab together with its overlying gold-bearing sulphide-rich sedimentary package, or indirectly through fluid released from a mantle lithosphere that was originally metasomatized and fertilized during an earlier subduction event. The fluid migrated up-dip from the mantle to crustal levels, through advection or seismic pumping along lithosphere- to crustal-scale fault zones, to form orogenic gold deposits within lower order structures. If these models are all accurate, then the GGB formed through subduction-related east-directed horizontal accretion at the continental margins of the Sebakwe Proto-Craton (SPC), and the genesis of felsite-hosted gold mineralization at Blue Rock could be explained eloquently through a universal orogenic gold model, in which mantle derived auriferous fluids were localised within lower order structures associated with felsites during the late stages of terrain accretion. Evidence from surface mapping and 3D modelling of exploratory drilling data, conducted during this research, strongly support the argument that the felsite hosted gold mineralization at Blue Rock, is neither unique nor accidental. It is just but, a simple product of the conjunction of favourable geological factors, no different to those that birthed typical GGB orogenic gold mineralization hosted within sheared sulphidic BIFs and quartz vein reefs. They all share the same geodynamic setting, fertility, preservation and regional architectural factors reminiscent of accretionary orogenic settings, albeit with differences in local architecture, variably controlled by geochemical and rheological properties of the different local host rocks. At deposit scale, the felsites occur as small dykes and sills emplaced along pre-existing structural zones of weakness. Gold mineralization is structurally controlled and associated mostly with brittle-ductile shears. During deformation, rheological contrast played a significant role in the selective failure of the more competent felsite rocks, resulting in the creation of permeability channels that allowed fluid migration. The more brittle and competent felsites acted as rigid bodies, that localised strain along their contacts with the surrounding less competent ductile mafic schists which acted as a relatively less permeable fluid cap rock. The irregular felsite contact zones with surrounding mafic schist caused a significant variation in the orientation of local principal maximum stress relative to the internally imposed regional stress, causing anomalously low minimum stress zones at deposit scale. Gold deposition occurred within low minimum stress structural traps dominated by sheared felsite contacts and their fractured interiors as well as triple junctions formed by complex structural geometries created by multiple felsite intrusions. The felsite hosted gold at Blue Rock can therefore be recognized as an orogenic gold mineral system archetype, for which an occurrence model is proposed. Understanding this type of mineralization is key for developing a robust exploration strategy - one that could be applied in a predictive capacity in exploration, to locate new economic gold deposits especially within well-endowed mature orogenic terrains, where exploration risk could be minimized by leveraging on new forward-thinking initiatives like Artificial Intelligence (AI) to re-analyze data from previous mining and exploration, allowing for a faster route to a return on investment. In a world of diminishing natural resources, the potential for previously ignored gold mineralization like the one at Blue Rock, becomes very significant. The prophetic words of Foster (1984), writing in Gold ‘82, therefore remain true and relevant to our time, that; “…. the way ahead for successful gold exploration is to search for new deposits not commonly recognized – in auriferous muds, disseminations in carbonate rocks, porphyries, and in felsic intrusive and extrusive volcanics…”. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
HI analysis of resolved galaxies in the MeerKAT Absorption Line Survey
- Authors: Maina, Eric Kamau
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466701 , vital:76771 , DOI https://doi.org/10.21504/10962/466701
- Description: This doctoral thesis examines two galaxy groups, Klemola 31 and UGC439, leveraging the observational capabilities of the MeerKAT Absorption Line Survey (MALS). The focus was on studying the interstellar medium, specifically the neutral hydrogen (H i) content, distribution, density, and dynamics, through high spatial resolution observations of these groups, and therefore offering insights into the complex processes affecting galaxy evolution in different environments. To make use of an additional tool, the absorption line characteristics of Hi in the two observed systems were analysed and compared with the kinematics and the morphology as induced by the observation of the Hi emission line in the same systems. For Klemola 31, this thesis identifies significant Hi deficiencies and interactions between member galaxies, with notable evidence of tidal interactions between Klemola 31 A and Klemola 31 B as well as ESO400-11 and LEDA2807038; and possible ram-pressure stripping in ESO400-13. The combined analysis of the Hi in emission and absorption indicates the presence of an extraplanar and potential intra-group medium in the group. The UGC439 group was observed in the commissioning phase of the MeerKAT array, revealing contrasting Hi distributions, with the central three galaxies indicating Hi excess while the peripheral galaxies indicating Hi deficiencies. There are two Hi clouds, one close to the central three galaxies and the other to the north. In this case, the observations are consistent with an Hi absorption system from within the disk of a galaxy. This thesis also highlights the necessity for further high spatial and spectral resolution observations to further reveal the intricacies of gas dynamics and its critical role in the life-cycle of galaxies. It serves as an outlook for further studies of the Hi environment of galaxies by combining absorption and emission line studies as first provided by MALS and ultimately by deep Hi surveys with the Square Kilometre Array. This thesis is organised into four chapters. The first chapter details a few concepts and background information about the physics of galaxy evolution. Chapter two talks about Klemola 31 galaxy group, where we start by describing our observation, data reduction and source finding. Thereafter, we explore the Hi morphology and kinematics of this group. In Chapter Three, we turn our attention to UGC439 galaxy group and organise it in a similar manner. A summary and comparison of the two groups is presented in Chapter 4. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Maina, Eric Kamau
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466701 , vital:76771 , DOI https://doi.org/10.21504/10962/466701
- Description: This doctoral thesis examines two galaxy groups, Klemola 31 and UGC439, leveraging the observational capabilities of the MeerKAT Absorption Line Survey (MALS). The focus was on studying the interstellar medium, specifically the neutral hydrogen (H i) content, distribution, density, and dynamics, through high spatial resolution observations of these groups, and therefore offering insights into the complex processes affecting galaxy evolution in different environments. To make use of an additional tool, the absorption line characteristics of Hi in the two observed systems were analysed and compared with the kinematics and the morphology as induced by the observation of the Hi emission line in the same systems. For Klemola 31, this thesis identifies significant Hi deficiencies and interactions between member galaxies, with notable evidence of tidal interactions between Klemola 31 A and Klemola 31 B as well as ESO400-11 and LEDA2807038; and possible ram-pressure stripping in ESO400-13. The combined analysis of the Hi in emission and absorption indicates the presence of an extraplanar and potential intra-group medium in the group. The UGC439 group was observed in the commissioning phase of the MeerKAT array, revealing contrasting Hi distributions, with the central three galaxies indicating Hi excess while the peripheral galaxies indicating Hi deficiencies. There are two Hi clouds, one close to the central three galaxies and the other to the north. In this case, the observations are consistent with an Hi absorption system from within the disk of a galaxy. This thesis also highlights the necessity for further high spatial and spectral resolution observations to further reveal the intricacies of gas dynamics and its critical role in the life-cycle of galaxies. It serves as an outlook for further studies of the Hi environment of galaxies by combining absorption and emission line studies as first provided by MALS and ultimately by deep Hi surveys with the Square Kilometre Array. This thesis is organised into four chapters. The first chapter details a few concepts and background information about the physics of galaxy evolution. Chapter two talks about Klemola 31 galaxy group, where we start by describing our observation, data reduction and source finding. Thereafter, we explore the Hi morphology and kinematics of this group. In Chapter Three, we turn our attention to UGC439 galaxy group and organise it in a similar manner. A summary and comparison of the two groups is presented in Chapter 4. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Immobilisation of an Aspergillus niger derived endo-1,4-β-mannanase, Man26A, for the production of prebiotic mannooligosaccharides from soybean meal
- Authors: Anderson, Amy Sage
- Date: 2024-10-11
- Subjects: Aspergillus niger , Soybean meal , Mannosidases , Oligosaccharides , Immobilized microorganisms
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463897 , vital:76455
- Description: This study investigated the potential for antibiotic alternatives in the form of prebiotics produced from the enzymatic breakdown of soybean meal (SBM). This study first investigated the immobilisation of an endo-1,4-β-mannanase derived from Aspergillus niger on glutaraldehyde-activated chitosan nanoparticles (CTS) and glutaraldehyde-activated chitosan-coated magnetic Fe3O4 nanoparticles (MAGS-CTS) - which could be effectively used to hydrolyse the galactomannan contained in SBM in a recyclable manner. The mannooligosaccharides (MOS) produced from the enzymatic digestion of SBM were then analysed for their prebiotic and antimicrobial capabilities to determine whether the strategy employed was capable of promoting and inhibiting probiotic and pathogenic growth, respectively. An Aspergillus niger endo-1,4-β-mannanase, Man26A, was confirmed by FTIR (Fourier-transform infrared spectroscopy) and XRD (X-ray powder diffraction) to be immobilised onto CTS and MAGS-CTS by covalent bonding. The immobilisation (%) and activity yields (%) were 81.14% and 35.45%, and 55.75% and 21.17%, respectively. The biochemical properties (pH and temperature optima, and temperature stability) of both the free CTS and MAGS-CTS immobilised Man26A enzymes were evaluated, with the pH optima shifting to a lower pH range after immobilisation (pH 2.0 – 3.0 vs. 5.0), while the temperature optima and stabilities remaining unchanged (at 60°C). CTS and free enzymes exhibited identical thermal stabilities, maintaining 100% activity for the first 6 hours at 55°C, while MAGS-CTS showed an immediate drop in relative activity after the first 30 minutes of incubation. Recyclability analysis revealed that CTS could be effectively reused for six reaction cycles, while the MAGS-CTS immobilised enzyme could only be used once. Both enzymes could be efficiently stored at 4ºC, showing a relative residual activity of 73% after 120 hours of storage. Substrate kinetic analysis showed that the free enzyme had the highest catalytic capabilities in hydrolysing locust bean gum (LBG), with the CTS immobilised enzyme was the most efficient in hydrolysing SBM, the insoluble, complex substrate. Sugar residues produced from the hydrolysis of LBG illustrated the effective breakdown of galactomannan to mannobiose (M2), mannotriose (M3), mannotetrose (M4), and mannohexose (M6). SBM-produced sugars analysed via TLC and HPLC indicated that the MOS residues were most probably glucose, galactose, and galactomannans (GM2 and GM3). The SBM-produced sugars were then evaluated for their prebiotic effect, illustrating their successful utilisation as a carbon source by probiotic bacteria; Streptococcus thermophilus, Bacillus subtilis and Lactobacillus bulgaricus. Evaluation of the antimicrobial activities of the SBM-produced sugars digested by probiotics suggested that their metabolites had the potential to be used as an antibiotic alternative. This study therefore illustrated that an endo-1,4-β-mannanase derived from Aspergillus niger could be immobilised successfully, for use in a recyclable reaction to produce MOS products. This study also described the successful use of SBM-sugars as a prebiotic, indicating a successful alternative to antibiotic growth promoters (AGP) by illustrating their positive effect on inhibiting growth of pathogenic bacterial species. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Anderson, Amy Sage
- Date: 2024-10-11
- Subjects: Aspergillus niger , Soybean meal , Mannosidases , Oligosaccharides , Immobilized microorganisms
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463897 , vital:76455
- Description: This study investigated the potential for antibiotic alternatives in the form of prebiotics produced from the enzymatic breakdown of soybean meal (SBM). This study first investigated the immobilisation of an endo-1,4-β-mannanase derived from Aspergillus niger on glutaraldehyde-activated chitosan nanoparticles (CTS) and glutaraldehyde-activated chitosan-coated magnetic Fe3O4 nanoparticles (MAGS-CTS) - which could be effectively used to hydrolyse the galactomannan contained in SBM in a recyclable manner. The mannooligosaccharides (MOS) produced from the enzymatic digestion of SBM were then analysed for their prebiotic and antimicrobial capabilities to determine whether the strategy employed was capable of promoting and inhibiting probiotic and pathogenic growth, respectively. An Aspergillus niger endo-1,4-β-mannanase, Man26A, was confirmed by FTIR (Fourier-transform infrared spectroscopy) and XRD (X-ray powder diffraction) to be immobilised onto CTS and MAGS-CTS by covalent bonding. The immobilisation (%) and activity yields (%) were 81.14% and 35.45%, and 55.75% and 21.17%, respectively. The biochemical properties (pH and temperature optima, and temperature stability) of both the free CTS and MAGS-CTS immobilised Man26A enzymes were evaluated, with the pH optima shifting to a lower pH range after immobilisation (pH 2.0 – 3.0 vs. 5.0), while the temperature optima and stabilities remaining unchanged (at 60°C). CTS and free enzymes exhibited identical thermal stabilities, maintaining 100% activity for the first 6 hours at 55°C, while MAGS-CTS showed an immediate drop in relative activity after the first 30 minutes of incubation. Recyclability analysis revealed that CTS could be effectively reused for six reaction cycles, while the MAGS-CTS immobilised enzyme could only be used once. Both enzymes could be efficiently stored at 4ºC, showing a relative residual activity of 73% after 120 hours of storage. Substrate kinetic analysis showed that the free enzyme had the highest catalytic capabilities in hydrolysing locust bean gum (LBG), with the CTS immobilised enzyme was the most efficient in hydrolysing SBM, the insoluble, complex substrate. Sugar residues produced from the hydrolysis of LBG illustrated the effective breakdown of galactomannan to mannobiose (M2), mannotriose (M3), mannotetrose (M4), and mannohexose (M6). SBM-produced sugars analysed via TLC and HPLC indicated that the MOS residues were most probably glucose, galactose, and galactomannans (GM2 and GM3). The SBM-produced sugars were then evaluated for their prebiotic effect, illustrating their successful utilisation as a carbon source by probiotic bacteria; Streptococcus thermophilus, Bacillus subtilis and Lactobacillus bulgaricus. Evaluation of the antimicrobial activities of the SBM-produced sugars digested by probiotics suggested that their metabolites had the potential to be used as an antibiotic alternative. This study therefore illustrated that an endo-1,4-β-mannanase derived from Aspergillus niger could be immobilised successfully, for use in a recyclable reaction to produce MOS products. This study also described the successful use of SBM-sugars as a prebiotic, indicating a successful alternative to antibiotic growth promoters (AGP) by illustrating their positive effect on inhibiting growth of pathogenic bacterial species. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Integrating sustainability into strategic decision making in the South African automotive sector
- Authors: Makaudi, Tuelo Ivan
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461874 , vital:76247
- Description: Sustainability has become a major topic for businesses, policy makers, government, and researchers. With the growing awareness of climate change, environmental and social problems, attention has turned to how businesses impact the environment, society, and economy. Sustainability, therefore, requires the integration of environmental and social issues into strategic decision making. Many organizations consider sustainability as an important issue for the business. However, some companies are struggling to combine business success and the success of other stakeholders, particularly those representing the interests of the environment and society. The purpose of this case study is to explore how sustainability is integrated into strategic decision making within some companies in the South African automotive industry. This study followed a qualitative approach, and semi-structured interviews were conducted with ten senior managers in the automotive sector in South Africa. The study used an inductive thematic analysis approach to analyse the data, and five main themes were generated: (1) Business profitability, (2) Organization culture, (3) Rationality, (4) Compliance, and (5) Corporate social responsibility (CSR). The findings of the study indicated that strategic decisions made considered business profitability first and foremost above environment and society. There is evidence that businesses engage in some sustainability activities, but this was related to the business objective to be profitable and to meet compliance requirements. The findings of the study also indicated that a rational decision-making approach was used predominantly, compared to intuitive and political approaches. This was due to the cautious approach of maintaining profit-making as a primary business objective. In terms of recommendations, this study recommends that automotive companies in South Africa integrate sustainability considerations into organizational/or business strategy to enable the industry to create shared value for the environment, society and economy. Integrating sustainability into business strategy will align business practices with sustainability goals and therefore allowing the automotive industry to have a positive impact in the society and environment which in turn will lead to improved financial performance. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Makaudi, Tuelo Ivan
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461874 , vital:76247
- Description: Sustainability has become a major topic for businesses, policy makers, government, and researchers. With the growing awareness of climate change, environmental and social problems, attention has turned to how businesses impact the environment, society, and economy. Sustainability, therefore, requires the integration of environmental and social issues into strategic decision making. Many organizations consider sustainability as an important issue for the business. However, some companies are struggling to combine business success and the success of other stakeholders, particularly those representing the interests of the environment and society. The purpose of this case study is to explore how sustainability is integrated into strategic decision making within some companies in the South African automotive industry. This study followed a qualitative approach, and semi-structured interviews were conducted with ten senior managers in the automotive sector in South Africa. The study used an inductive thematic analysis approach to analyse the data, and five main themes were generated: (1) Business profitability, (2) Organization culture, (3) Rationality, (4) Compliance, and (5) Corporate social responsibility (CSR). The findings of the study indicated that strategic decisions made considered business profitability first and foremost above environment and society. There is evidence that businesses engage in some sustainability activities, but this was related to the business objective to be profitable and to meet compliance requirements. The findings of the study also indicated that a rational decision-making approach was used predominantly, compared to intuitive and political approaches. This was due to the cautious approach of maintaining profit-making as a primary business objective. In terms of recommendations, this study recommends that automotive companies in South Africa integrate sustainability considerations into organizational/or business strategy to enable the industry to create shared value for the environment, society and economy. Integrating sustainability into business strategy will align business practices with sustainability goals and therefore allowing the automotive industry to have a positive impact in the society and environment which in turn will lead to improved financial performance. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2024
- Full Text:
- Date Issued: 2024-10-11
Interaction of Arbuscular Mycorrhiza and Solanum Tuberosum
- Authors: Chifetete, Varaidzo Winnie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466513 , vital:76737
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chifetete, Varaidzo Winnie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466513 , vital:76737
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating deep-seated factors that can condition English First Additional Language literature teaching in Grade 7
- Authors: Ntikinca, Xolela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463757 , vital:76438
- Description: Access restricted. Expected release in 2026. , Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes of Africa, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ntikinca, Xolela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463757 , vital:76438
- Description: Access restricted. Expected release in 2026. , Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes of Africa, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating optoelectronic and thermal properties of perylene tetracarboxylic bisimide derivatives-and-cellulose nanocomposites for possible solar energy applications
- Ndwandwe, Bongeka Lethukukhanya
- Authors: Ndwandwe, Bongeka Lethukukhanya
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464554 , vital:76521
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ndwandwe, Bongeka Lethukukhanya
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464554 , vital:76521
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating teachers’ post-pandemic management of mathematics content coverage in Grade 3
- Authors: Damaske, Inge Gerda
- Date: 2024-10-11
- Subjects: COVID-19 Pandemic, 2020- Influence , Mathematics Study and teaching (Elementary) South Africa City of Tshwane Metropolitan Municipality , Elementary school teachers South Africa City of Tshwane Metropolitan Municipality , Educational technology , Curriculum planning
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463691 , vital:76432
- Description: This study investigated how teachers managed and continue to manage mathematics content coverage in Grade 3 during the COVID-19 pandemic and now post the pandemic. In particular my study sought to understand technologies that teachers may have drawn on during the pandemic in support of curriculum coverage and those that they continue to use. In addition, the study began with a detailed documentary analysis of all available documentation provided to schools and teachers about the management of teaching and curriculum coverage during the pandemic as this provides understanding of the policy and guidelines context in which teachers were working. Thus, in this research I investigated the research questions: i) How have teachers managed the stipulated curriculum coverage in Grade 3 mathematics during the pandemic? and ii) How are teachers continuing to manage this post the pandemic. This included identifying how much and what type of support teachers were given from various stakeholders in the primary education system. Here the levels of support from school principals, governing bodies and more importantly the Department of Basic Education were analysed. This research, situated within an interpretative paradigm, was guided by the sociocultural theory inherent in the concerns-based adoption model. The levels of use within the concerns-based adoption model were adapted to suit the South African context of the study. Participants of the study were 18 teachers from different quintile schools within the Tshwane South District. Key findings included that the Department of Basic Education (DBE) provided a range of documents aimed at adjusting content coverage in response to the altered school calendar during the pandemic. Notable adjustments, particularly in the Annual Teaching Plans (ATPs) of 2020, revealed discrepancies in allocated school days and modifications in content areas such as numbers, operations, geometry, measurement, and data handling. The reduction in the number range and fluctuations in measurement components were observed. Despite the provision of guidelines, the study notes challenges in maintaining continuity and optimal learning, with indications of non-compliance with provided ATPs. The study further found that teachers in different quintile schools adopted diverse strategies for mathematics content coverage during the pandemic. Quintile 5 schools, often well-resourced, reported effective remote teaching using tools like PowerPoint and MS Teams. In contrast, teachers in quintiles 3 and 4, more impacted by school closures, employed varied methods, including extra lessons. Surprisingly, teachers in well-resourced private schools reported gaps in learners' mathematical knowledge, emphasizing the flexibility they have in curriculum coverage. Technology played a pivotal role in facilitating remote teaching during the pandemic, with tools like WhatsApp, MS Teams, and Zoom being widely used, where available. The study underscored the impact of technology on curriculum coverage, especially in well-resourced schools. Grade 3 teachers expressed challenges in meeting unrealistic expectations for curriculum coverage, citing gaps in learners' understanding. The study highlighted a discrepancy between the resources provided by the DBE and the actual needs on the ground, signalling a need for policymakers to become more understanding to the situations in schools. The lack of support from the DBE prompted teachers to become flexible, adapting teaching strategies and supporting each other to navigate the challenges posed by the pandemic. The study concludes by noting the evolving mindset of teachers, transitioning through different levels of Concerns-Based Adoption Model (CBAM), ultimately showcasing their resilience and adaptability in managing curriculum coverage with the available resources. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Damaske, Inge Gerda
- Date: 2024-10-11
- Subjects: COVID-19 Pandemic, 2020- Influence , Mathematics Study and teaching (Elementary) South Africa City of Tshwane Metropolitan Municipality , Elementary school teachers South Africa City of Tshwane Metropolitan Municipality , Educational technology , Curriculum planning
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463691 , vital:76432
- Description: This study investigated how teachers managed and continue to manage mathematics content coverage in Grade 3 during the COVID-19 pandemic and now post the pandemic. In particular my study sought to understand technologies that teachers may have drawn on during the pandemic in support of curriculum coverage and those that they continue to use. In addition, the study began with a detailed documentary analysis of all available documentation provided to schools and teachers about the management of teaching and curriculum coverage during the pandemic as this provides understanding of the policy and guidelines context in which teachers were working. Thus, in this research I investigated the research questions: i) How have teachers managed the stipulated curriculum coverage in Grade 3 mathematics during the pandemic? and ii) How are teachers continuing to manage this post the pandemic. This included identifying how much and what type of support teachers were given from various stakeholders in the primary education system. Here the levels of support from school principals, governing bodies and more importantly the Department of Basic Education were analysed. This research, situated within an interpretative paradigm, was guided by the sociocultural theory inherent in the concerns-based adoption model. The levels of use within the concerns-based adoption model were adapted to suit the South African context of the study. Participants of the study were 18 teachers from different quintile schools within the Tshwane South District. Key findings included that the Department of Basic Education (DBE) provided a range of documents aimed at adjusting content coverage in response to the altered school calendar during the pandemic. Notable adjustments, particularly in the Annual Teaching Plans (ATPs) of 2020, revealed discrepancies in allocated school days and modifications in content areas such as numbers, operations, geometry, measurement, and data handling. The reduction in the number range and fluctuations in measurement components were observed. Despite the provision of guidelines, the study notes challenges in maintaining continuity and optimal learning, with indications of non-compliance with provided ATPs. The study further found that teachers in different quintile schools adopted diverse strategies for mathematics content coverage during the pandemic. Quintile 5 schools, often well-resourced, reported effective remote teaching using tools like PowerPoint and MS Teams. In contrast, teachers in quintiles 3 and 4, more impacted by school closures, employed varied methods, including extra lessons. Surprisingly, teachers in well-resourced private schools reported gaps in learners' mathematical knowledge, emphasizing the flexibility they have in curriculum coverage. Technology played a pivotal role in facilitating remote teaching during the pandemic, with tools like WhatsApp, MS Teams, and Zoom being widely used, where available. The study underscored the impact of technology on curriculum coverage, especially in well-resourced schools. Grade 3 teachers expressed challenges in meeting unrealistic expectations for curriculum coverage, citing gaps in learners' understanding. The study highlighted a discrepancy between the resources provided by the DBE and the actual needs on the ground, signalling a need for policymakers to become more understanding to the situations in schools. The lack of support from the DBE prompted teachers to become flexible, adapting teaching strategies and supporting each other to navigate the challenges posed by the pandemic. The study concludes by noting the evolving mindset of teachers, transitioning through different levels of Concerns-Based Adoption Model (CBAM), ultimately showcasing their resilience and adaptability in managing curriculum coverage with the available resources. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating the relationship between Adverse Childhood Experiences (ACE) and attention skills in children living with HIV
- Authors: Ngomane, Sibongile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465821 , vital:76656
- Description: Background: While persons living with HIV (PWH) have benefited from significant advances in antiretroviral (ARV) treatment, neurocognitive deficits sequent HIV, remain elevated in this population. Notwithstanding HIV, adverse childhood experiences (ACEs) have been implicated in compromised neurocognitive outcomes in children living with HIV. There however, continues to be a dearth of research, investigating the intertwined nature of HIV, ACEs, and neurocognition in pediatric and adolescent HIV. Objectives: This study investigated the relationship between ACEs (High vs Low) and attention outcomes, in children and adolescents, living with HIV, a residing at HIV care shelters in South Africa. Methods: A non-experimental quantitative research design, inclusive of 42 participants (n = 22 males; n = 20 females), was employed to answer the research questions pertinent to the study. Measures of neurocognition were assessed using the NEPSY-II. Adverse childhood experiences were assessed using the ACE CYW-Qs. Independent Sample t-test and Hierarchical regression analysis were conducted to answer research goals, using jamovi 2.3.21 statistical software. Results: The study found that participants who reported a high number of ACEs also performed poorly on attention measures. There were inconclusive findings on the effect of biological sex and age, on attention outcomes. Conclusion: Higher levels of childhood adversities are associated with poorer outcomes in attention scores among children living with HIV. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ngomane, Sibongile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465821 , vital:76656
- Description: Background: While persons living with HIV (PWH) have benefited from significant advances in antiretroviral (ARV) treatment, neurocognitive deficits sequent HIV, remain elevated in this population. Notwithstanding HIV, adverse childhood experiences (ACEs) have been implicated in compromised neurocognitive outcomes in children living with HIV. There however, continues to be a dearth of research, investigating the intertwined nature of HIV, ACEs, and neurocognition in pediatric and adolescent HIV. Objectives: This study investigated the relationship between ACEs (High vs Low) and attention outcomes, in children and adolescents, living with HIV, a residing at HIV care shelters in South Africa. Methods: A non-experimental quantitative research design, inclusive of 42 participants (n = 22 males; n = 20 females), was employed to answer the research questions pertinent to the study. Measures of neurocognition were assessed using the NEPSY-II. Adverse childhood experiences were assessed using the ACE CYW-Qs. Independent Sample t-test and Hierarchical regression analysis were conducted to answer research goals, using jamovi 2.3.21 statistical software. Results: The study found that participants who reported a high number of ACEs also performed poorly on attention measures. There were inconclusive findings on the effect of biological sex and age, on attention outcomes. Conclusion: Higher levels of childhood adversities are associated with poorer outcomes in attention scores among children living with HIV. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
IT business consulting competencies to address business intelligence and analytics challenges in South African organisations
- Authors: Chatapura, Ruvimbo Faith
- Date: 2024-10-11
- Subjects: Business enterprises Information technology South Africa , Business intelligence , Business analytics , Business consultants , Dynamic capabilities , Knowledge management
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462680 , vital:76325
- Description: Background: In today's dynamic environment, the importance and popularity of business intelligence and analytics (BI&A) has increased due to the rise in big data being generated across the globe. BI&A is an essential emerging business competency area and dynamic capability that serves as an enabler for organisations to harvest value from their big data. When implemented correctly, BI&A is a powerful tool that leads to increased competitive advantage. However, organisations in South Africa are facing major challenges when it comes to adopting and harnessing it. As such, it is IT business consultants that South African organisations turn to for acquiring BI&A expertise. Objective: Using the Theory of Dynamic Capabilities as an underpinning lens, the purpose of this study is to investigate the relevant competencies IT business consultants need to address BI&A challenges in South African organisations. This study focuses on developing a BI&A competency framework based on these competencies that IT business consultants can consider when addressing the BI&A challenges in South African organisations. Methods: A qualitative research approach was utilised in this study by making use of an interpretive paradigm, abductive reasoning, qualitative description research strategy, as well as semi-structured interviews and questionnaires as data collection methods to elicit feedback on this study’s BI&A competency framework. Content analysis was conducted to categorise and code the interview data, and descriptive analysis was conducted to rank the competencies in order of relevance. Findings: It was found that the relevant business competencies to consider are business acumen, industry knowledge and strategic conceptual abilities. The relevant technical competencies are categorised into three categories: analytical skills (logical thinking, problem-solving, statistical analysis and what-if analysis), data engineering (data modelling skills, data warehousing, database management, data governance, data interpretation, data stewardship, data visualisation tools and data processing languages) and supplementary skills (project management, consulting skills and artificial intelligence). The relevant values and behavioural competencies to consider are integrity, communication, teamwork, resilience, commitment, creativity, emotional intelligence, humility, behavioural analysis, curiosity, leadership and social intelligence. , Thesis (MCom) -- Faculty of Commerce, Information Systems, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chatapura, Ruvimbo Faith
- Date: 2024-10-11
- Subjects: Business enterprises Information technology South Africa , Business intelligence , Business analytics , Business consultants , Dynamic capabilities , Knowledge management
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462680 , vital:76325
- Description: Background: In today's dynamic environment, the importance and popularity of business intelligence and analytics (BI&A) has increased due to the rise in big data being generated across the globe. BI&A is an essential emerging business competency area and dynamic capability that serves as an enabler for organisations to harvest value from their big data. When implemented correctly, BI&A is a powerful tool that leads to increased competitive advantage. However, organisations in South Africa are facing major challenges when it comes to adopting and harnessing it. As such, it is IT business consultants that South African organisations turn to for acquiring BI&A expertise. Objective: Using the Theory of Dynamic Capabilities as an underpinning lens, the purpose of this study is to investigate the relevant competencies IT business consultants need to address BI&A challenges in South African organisations. This study focuses on developing a BI&A competency framework based on these competencies that IT business consultants can consider when addressing the BI&A challenges in South African organisations. Methods: A qualitative research approach was utilised in this study by making use of an interpretive paradigm, abductive reasoning, qualitative description research strategy, as well as semi-structured interviews and questionnaires as data collection methods to elicit feedback on this study’s BI&A competency framework. Content analysis was conducted to categorise and code the interview data, and descriptive analysis was conducted to rank the competencies in order of relevance. Findings: It was found that the relevant business competencies to consider are business acumen, industry knowledge and strategic conceptual abilities. The relevant technical competencies are categorised into three categories: analytical skills (logical thinking, problem-solving, statistical analysis and what-if analysis), data engineering (data modelling skills, data warehousing, database management, data governance, data interpretation, data stewardship, data visualisation tools and data processing languages) and supplementary skills (project management, consulting skills and artificial intelligence). The relevant values and behavioural competencies to consider are integrity, communication, teamwork, resilience, commitment, creativity, emotional intelligence, humility, behavioural analysis, curiosity, leadership and social intelligence. , Thesis (MCom) -- Faculty of Commerce, Information Systems, 2024
- Full Text:
- Date Issued: 2024-10-11
KalCal: a novel calibration framework for radio interferometry using the Kalman Filter and Smoother
- Authors: Welman, Brian Allister
- Date: 2024-10-11
- Subjects: Radio interferometers , Calibration , Kalman filtering , Bayesian inference , Signal processing , Radio astronomy , MeerKAT
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/467127 , vital:76818
- Description: Calibration in radio interferometry is essential for correcting measurement errors. Traditional methods employ maximum likelihood techniques and non-linear least squares solvers but face challenges due to the data volumes and increased noise sensitivity of contemporary instruments such as MeerKAT. A common approach for mitigating these issues is using “solution intervals”, which helps manage the data volume and reduces overfitting. However, inappropriate interval sizes can degrade calibration quality, and determining optimal sizes is challenging, often relying on brute-force methods. This study introduces Kalman Filtering and Smoothing in Calibration (KalCal), a new framework for calibration that combines the Kalman Filter, Kalman Smoother, and the energy function: the negative logarithm of the Bayesian evidence. KalCal offers Bayesian-optimal solutions as probability densities and models calibration effects with lower computational requirements than iterative approaches. Unlike traditional methods, which require all the data for a particular solution to be in memory simultaneously, KalCal’s recursive computations only need a single pass through the data with appropriate prior information. The energy function provides the means for KalCal to determine this prior information. Theoretical contributions include additions to complex optimisation literature and the “Kalman-Woodbury Identity” that reformulates the traditional Kalman Filter. A Python implementation of the KalCal framework was benchmarked against solution intervals as implemented in the QuartiCal package. Simulations show KalCal matching solution intervals in high Signal-to-Noise Ratio (SNR) scenarios and surpassing them in low SNR conditions. Moreover, the energy function produced minima that coincide with KalCal’s Mean Square Error (MSE) on the true gain signal. This result is significant as the MSE is unavailable in real applications. Further research is needed to assess the computational feasibility and intricacies of KalCal. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Welman, Brian Allister
- Date: 2024-10-11
- Subjects: Radio interferometers , Calibration , Kalman filtering , Bayesian inference , Signal processing , Radio astronomy , MeerKAT
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/467127 , vital:76818
- Description: Calibration in radio interferometry is essential for correcting measurement errors. Traditional methods employ maximum likelihood techniques and non-linear least squares solvers but face challenges due to the data volumes and increased noise sensitivity of contemporary instruments such as MeerKAT. A common approach for mitigating these issues is using “solution intervals”, which helps manage the data volume and reduces overfitting. However, inappropriate interval sizes can degrade calibration quality, and determining optimal sizes is challenging, often relying on brute-force methods. This study introduces Kalman Filtering and Smoothing in Calibration (KalCal), a new framework for calibration that combines the Kalman Filter, Kalman Smoother, and the energy function: the negative logarithm of the Bayesian evidence. KalCal offers Bayesian-optimal solutions as probability densities and models calibration effects with lower computational requirements than iterative approaches. Unlike traditional methods, which require all the data for a particular solution to be in memory simultaneously, KalCal’s recursive computations only need a single pass through the data with appropriate prior information. The energy function provides the means for KalCal to determine this prior information. Theoretical contributions include additions to complex optimisation literature and the “Kalman-Woodbury Identity” that reformulates the traditional Kalman Filter. A Python implementation of the KalCal framework was benchmarked against solution intervals as implemented in the QuartiCal package. Simulations show KalCal matching solution intervals in high Signal-to-Noise Ratio (SNR) scenarios and surpassing them in low SNR conditions. Moreover, the energy function produced minima that coincide with KalCal’s Mean Square Error (MSE) on the true gain signal. This result is significant as the MSE is unavailable in real applications. Further research is needed to assess the computational feasibility and intricacies of KalCal. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Macroinvertebrate population dynamics, community composition and diversity patterns of two coastal lakes in northern KwaZulu-Natal, South Africa
- Authors: Campbell, Kaylee Maria
- Date: 2024-10-11
- Subjects: Indicators (Biology) , Lakes South Africa KwaZulu-Natal , Sibayi, Lake (South Africa) , Lake Mzingazi Dam , Biological monitoring South Africa KwaZulu-Natal , Biodiversity , Geospatial data South Africa KwaZulu-Natal , Land use Planning South Africa KwaZulu-Natal
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464406 , vital:76508
- Description: The 2018 South African National Biodiversity Assessment (NBA) identified eight freshwater lakes of national ecological importance and a lack of understanding of their biology. The assessment further called for baseline foundational data for their conservation. Aquatic invertebrates are considered to be reliable and sensitive biological indicators of environmental and water quality changes, and understanding aquatic invertebrate dynamics in these systems will provide a comprehensive understanding of how they can be better protected. The NBA also highlighted a gap in data associated with ecological response to landscape developments and climate change (mainly below average precipitation and increased temperatures) and how this contributes to aquatic resource conservation. This further complicates the modelling of important ecological thresholds and hampers the prediction of possible responses of these ecosystems to environmental changes. This gap informed the aims and rationale of this dissertation; to identify longer-term spatiotemporal trends in aquatic invertebrate communities in Lake Sibaya and Lake Mzingazi and to determine whether the surrounding land use changes could lead to long-term changes in aquatic invertebrate communities of both lakes by comparing recent survey data with historical datasets. In Chapter 2, this dissertation investigated the population dynamics of freshwater shrimp, Caridina africana in Lake Sibaya and Mzingazi and compared the data to that of 1975 study published by Hart (1981). This was done to assess any changes in the C. africana populations due to the considerable changes in land use and weather patterns that have occurred in the last 48 years in and around the systems. Results from Lake Sibaya and Lake Mzingazi were also compared to determine any differences in urban and agricultural stressors presented to C. africana populations. This chapter hypothesised that increases in anthropogenic pollution, invasive species and other habitat modifications at Lake Sibaya and Lake Mzingazi would lead to (1) reductions in shrimp densities and changes in population dynamics when comparing with the 1975 data from Hart (1981). Additionally, it was predicted that (2) Caridina africana abundances found at Lake Mzingazi would be lower than those found at Lake Sibaya (3) due to different water quality variables associated with land use. Results showed that C. africana population densities at Lake Sibaya and lake level recordings had experienced significant decreases since 1975 with densities being significantly lower in 2021. Additional differences seen in 2021 when compared to 1975 were that females were more abundant than males, individuals between the sizes of 3mm and 5mm were most abundant instead of those in the smallest size class (<0.83mm – 1.67mm) and females only dominated size classes above 4mm instead of all size classes above 2.5mm. Populations at Lake Sibaya were negatively correlated with nitrate concentrations in 2021 and populations at Lake Mzingazi were negatively correlated with temperature according to generalised linear models. These results emphasized the importance of pollution mitigation, sustainable water abstraction and the maintenance of natural water temperature ranges in the conservation of lentic C. africana populations. There was also no evidence that urbanisation and agriculture presented different threats to freshwater shrimp populations. In Chapter 3, this dissertation aimed to quantify the littoral aquatic invertebrate diversity and assemblage patterns from Lake Sibaya and Lake Mzingazi to provide comprehensive baseline datasets for these coastal systems. This chapter also aimed to investigate the impacts of landscape developments and habitat change on aquatic invertebrate communities by understanding significant water quality parameters as drivers of community variation. Predictions for Chapter 3 were that increases in agricultural and anthropogenic disturbance and habitat modification will lead to (1) aquatic invertebrate community composition at lakes Sibaya and Mzingazi being structured according to water quality variables that stem from surrounding land-use activities, leading to (2) differing community structures at each lake. Lastly, it was hypothesised that (3) the presence of the invasive snail Tarebia granifera would likely be affecting the aquatic invertebrate diversity and composition of both lakes. According to linear models, aquatic invertebrate abundance at Lake Sibaya was negatively affected by salinity, lake level and phosphate concentration, and positively associated with temperature. Taxa richness and Pielou’s evenness at the lake were negatively associated with conductivity and nitrate concentrations respectively. The aquatic invertebrate community at Lake Sibaya also followed typical seasonal patterns. At Lake Mzingazi, Pielou’s evenness was negatively associated with nitrate and ammonium concentrations and no typical seasonal patterns were evident in the community composition. Communities at Lake Mzingazi also exhibited resilience despite changes in physicochemical parameters, emphasising the difficulty in predicting aquatic community response to habitat modification due to lake-specific community resilience. Tarebia granifera populations at Lake Sibaya were found to negatively affect invertebrate diversity scores according to generalised linear models. Additionally, no individuals of Melanoides tuberculata were found in either system indicating the possibility that these native snails may have been outcompeted by their invasive counterpart. The prevalence of significant stressors associated with habitat disturbance and the unexpected results seen at Lake Mzingazi emphasized the importance of monitoring aquatic invertebrate communities in response to climate change and associated land use developments to adequately understand the long-term threats these changes pose to freshwater ecosystems and biodiversity conservation. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Campbell, Kaylee Maria
- Date: 2024-10-11
- Subjects: Indicators (Biology) , Lakes South Africa KwaZulu-Natal , Sibayi, Lake (South Africa) , Lake Mzingazi Dam , Biological monitoring South Africa KwaZulu-Natal , Biodiversity , Geospatial data South Africa KwaZulu-Natal , Land use Planning South Africa KwaZulu-Natal
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464406 , vital:76508
- Description: The 2018 South African National Biodiversity Assessment (NBA) identified eight freshwater lakes of national ecological importance and a lack of understanding of their biology. The assessment further called for baseline foundational data for their conservation. Aquatic invertebrates are considered to be reliable and sensitive biological indicators of environmental and water quality changes, and understanding aquatic invertebrate dynamics in these systems will provide a comprehensive understanding of how they can be better protected. The NBA also highlighted a gap in data associated with ecological response to landscape developments and climate change (mainly below average precipitation and increased temperatures) and how this contributes to aquatic resource conservation. This further complicates the modelling of important ecological thresholds and hampers the prediction of possible responses of these ecosystems to environmental changes. This gap informed the aims and rationale of this dissertation; to identify longer-term spatiotemporal trends in aquatic invertebrate communities in Lake Sibaya and Lake Mzingazi and to determine whether the surrounding land use changes could lead to long-term changes in aquatic invertebrate communities of both lakes by comparing recent survey data with historical datasets. In Chapter 2, this dissertation investigated the population dynamics of freshwater shrimp, Caridina africana in Lake Sibaya and Mzingazi and compared the data to that of 1975 study published by Hart (1981). This was done to assess any changes in the C. africana populations due to the considerable changes in land use and weather patterns that have occurred in the last 48 years in and around the systems. Results from Lake Sibaya and Lake Mzingazi were also compared to determine any differences in urban and agricultural stressors presented to C. africana populations. This chapter hypothesised that increases in anthropogenic pollution, invasive species and other habitat modifications at Lake Sibaya and Lake Mzingazi would lead to (1) reductions in shrimp densities and changes in population dynamics when comparing with the 1975 data from Hart (1981). Additionally, it was predicted that (2) Caridina africana abundances found at Lake Mzingazi would be lower than those found at Lake Sibaya (3) due to different water quality variables associated with land use. Results showed that C. africana population densities at Lake Sibaya and lake level recordings had experienced significant decreases since 1975 with densities being significantly lower in 2021. Additional differences seen in 2021 when compared to 1975 were that females were more abundant than males, individuals between the sizes of 3mm and 5mm were most abundant instead of those in the smallest size class (<0.83mm – 1.67mm) and females only dominated size classes above 4mm instead of all size classes above 2.5mm. Populations at Lake Sibaya were negatively correlated with nitrate concentrations in 2021 and populations at Lake Mzingazi were negatively correlated with temperature according to generalised linear models. These results emphasized the importance of pollution mitigation, sustainable water abstraction and the maintenance of natural water temperature ranges in the conservation of lentic C. africana populations. There was also no evidence that urbanisation and agriculture presented different threats to freshwater shrimp populations. In Chapter 3, this dissertation aimed to quantify the littoral aquatic invertebrate diversity and assemblage patterns from Lake Sibaya and Lake Mzingazi to provide comprehensive baseline datasets for these coastal systems. This chapter also aimed to investigate the impacts of landscape developments and habitat change on aquatic invertebrate communities by understanding significant water quality parameters as drivers of community variation. Predictions for Chapter 3 were that increases in agricultural and anthropogenic disturbance and habitat modification will lead to (1) aquatic invertebrate community composition at lakes Sibaya and Mzingazi being structured according to water quality variables that stem from surrounding land-use activities, leading to (2) differing community structures at each lake. Lastly, it was hypothesised that (3) the presence of the invasive snail Tarebia granifera would likely be affecting the aquatic invertebrate diversity and composition of both lakes. According to linear models, aquatic invertebrate abundance at Lake Sibaya was negatively affected by salinity, lake level and phosphate concentration, and positively associated with temperature. Taxa richness and Pielou’s evenness at the lake were negatively associated with conductivity and nitrate concentrations respectively. The aquatic invertebrate community at Lake Sibaya also followed typical seasonal patterns. At Lake Mzingazi, Pielou’s evenness was negatively associated with nitrate and ammonium concentrations and no typical seasonal patterns were evident in the community composition. Communities at Lake Mzingazi also exhibited resilience despite changes in physicochemical parameters, emphasising the difficulty in predicting aquatic community response to habitat modification due to lake-specific community resilience. Tarebia granifera populations at Lake Sibaya were found to negatively affect invertebrate diversity scores according to generalised linear models. Additionally, no individuals of Melanoides tuberculata were found in either system indicating the possibility that these native snails may have been outcompeted by their invasive counterpart. The prevalence of significant stressors associated with habitat disturbance and the unexpected results seen at Lake Mzingazi emphasized the importance of monitoring aquatic invertebrate communities in response to climate change and associated land use developments to adequately understand the long-term threats these changes pose to freshwater ecosystems and biodiversity conservation. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
Mediating learning of electrostatics through stories on cultural beliefs and practices about lightning to Grade 7 township school learners
- Authors: Funani, Lindiso Desmond
- Date: 2024-10-11
- Subjects: Science Study and teaching (Primary) South Africa , Electrostatics , Lightning South Africa , Traditional ecological knowledge South Africa , Argumentation theory , Social learning South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463548 , vital:76419
- Description: The Curriculum and Assessment Policy Statement (CAPS) document mandates that teaching and learning should start with the knowledge and experiences of learners from home or communities when teaching Natural Sciences. The aim is to bridge the gap between the science content learned in the school classroom and the science accessible to learners in their homes and community environments. CAPS claims that it ‘embraces local indigenous knowledge’ but it does not specify how this should be done in schools. As a result, little or no integration of Indigenous Knowledge (IK) is enacted in many of our schools in South Africa and learners seem to find science inaccessible and irrelevant to their everyday lives. It is against this backdrop that this interventionist study sought to mediate learning of electrostatics through harnessing stories on cultural beliefs and practices about lightning to Grade 7 township school learners. This study is located within the interpretivist and Indigenous research paradigms, central to which is to develop a greater understanding of how people make sense of the contexts in which they live and work. Within the Indigenous research paradigm, I focused on the Ubuntu perspective. Furthermore, this study was conducted in an under-resourced school located in the Sarah Baartman District, Eastern Cape Province of South Africa. The participants were Grade 7 Natural Sciences learners and two Indigenous Knowledge Custodians (IKCs). In addition, one Natural Sciences teacher was my critical friend. Focus group interviews (sharing circles), group activities, observations (participatory and lesson observation), and learners’ journals were used to gather data. Vygotsky’s sociocultural theory and Ogunniyi’s Contiguity Argumentation Theory were used as theoretical frameworks in this study. The findings of the study revealed that both the group activity and the presentations by the Indigenous Knowledge Custodians on stories on cultural beliefs and practices about lightning enabled learners’ argumentation and sense-making of electrostatics. The study thus recommends that science teachers should make efforts to tap into the cultural heritage of IKCs to make science accessible and relevant to learners' everyday life experiences. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Funani, Lindiso Desmond
- Date: 2024-10-11
- Subjects: Science Study and teaching (Primary) South Africa , Electrostatics , Lightning South Africa , Traditional ecological knowledge South Africa , Argumentation theory , Social learning South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463548 , vital:76419
- Description: The Curriculum and Assessment Policy Statement (CAPS) document mandates that teaching and learning should start with the knowledge and experiences of learners from home or communities when teaching Natural Sciences. The aim is to bridge the gap between the science content learned in the school classroom and the science accessible to learners in their homes and community environments. CAPS claims that it ‘embraces local indigenous knowledge’ but it does not specify how this should be done in schools. As a result, little or no integration of Indigenous Knowledge (IK) is enacted in many of our schools in South Africa and learners seem to find science inaccessible and irrelevant to their everyday lives. It is against this backdrop that this interventionist study sought to mediate learning of electrostatics through harnessing stories on cultural beliefs and practices about lightning to Grade 7 township school learners. This study is located within the interpretivist and Indigenous research paradigms, central to which is to develop a greater understanding of how people make sense of the contexts in which they live and work. Within the Indigenous research paradigm, I focused on the Ubuntu perspective. Furthermore, this study was conducted in an under-resourced school located in the Sarah Baartman District, Eastern Cape Province of South Africa. The participants were Grade 7 Natural Sciences learners and two Indigenous Knowledge Custodians (IKCs). In addition, one Natural Sciences teacher was my critical friend. Focus group interviews (sharing circles), group activities, observations (participatory and lesson observation), and learners’ journals were used to gather data. Vygotsky’s sociocultural theory and Ogunniyi’s Contiguity Argumentation Theory were used as theoretical frameworks in this study. The findings of the study revealed that both the group activity and the presentations by the Indigenous Knowledge Custodians on stories on cultural beliefs and practices about lightning enabled learners’ argumentation and sense-making of electrostatics. The study thus recommends that science teachers should make efforts to tap into the cultural heritage of IKCs to make science accessible and relevant to learners' everyday life experiences. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Mediating learning of nutrition through using traditional food processing and preservation to grade 6 rural school learners
- Authors: Tyeda, Nomvume
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463658 , vital:76429
- Description: Rural learners, especially those in the school where I teach, seem to grasp science in a disconnected manner, and hence struggle to understand it. This concern aligns with the findings of the Trends of International Mathematics and Science Studies, which notes poor performance in science among learners in South Africa. When examining these challenges, learners appear to inhabit a realm divided by a river, struggling to bridge the gap between what they learn at home and what is taught at school. Against this context, this research aimed to mediate the learning of nutrition for Grade 6 rural school learners by integrating traditional ways of food processing and preservation. The interpretivist and Indigenous research paradigms underpin the research. I used the Ubuntu perspective within the Indigenous research paradigm, which emphasises respect and humble togetherness. This qualitative case study took place at a rural school in the OR Tambo Coastal district in the Eastern Cape. It involved 14 Grade 6 Natural Sciences and Technology learners, a critical friend, and two Indigenous Knowledge Custodians. Various methods were used to collect data, including group activities by learners, participatory and lesson observation, focus group interviews (sharing circles), and learners’ journal reflections. The findings of the study revealed the significance of integrating Indigenous Knowledge with modern scientific principles, engaging in experiential and hands-on learning activities, involving Indigenous Knowledge Custodians, and using visual learning aids to enhance learners’ engagement and sense-making of nutrition. The study recommends that Indigenous Knowledge should be integrated with modern science to provide a comprehensive understanding of the topic of nutrition. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Tyeda, Nomvume
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463658 , vital:76429
- Description: Rural learners, especially those in the school where I teach, seem to grasp science in a disconnected manner, and hence struggle to understand it. This concern aligns with the findings of the Trends of International Mathematics and Science Studies, which notes poor performance in science among learners in South Africa. When examining these challenges, learners appear to inhabit a realm divided by a river, struggling to bridge the gap between what they learn at home and what is taught at school. Against this context, this research aimed to mediate the learning of nutrition for Grade 6 rural school learners by integrating traditional ways of food processing and preservation. The interpretivist and Indigenous research paradigms underpin the research. I used the Ubuntu perspective within the Indigenous research paradigm, which emphasises respect and humble togetherness. This qualitative case study took place at a rural school in the OR Tambo Coastal district in the Eastern Cape. It involved 14 Grade 6 Natural Sciences and Technology learners, a critical friend, and two Indigenous Knowledge Custodians. Various methods were used to collect data, including group activities by learners, participatory and lesson observation, focus group interviews (sharing circles), and learners’ journal reflections. The findings of the study revealed the significance of integrating Indigenous Knowledge with modern scientific principles, engaging in experiential and hands-on learning activities, involving Indigenous Knowledge Custodians, and using visual learning aids to enhance learners’ engagement and sense-making of nutrition. The study recommends that Indigenous Knowledge should be integrated with modern science to provide a comprehensive understanding of the topic of nutrition. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11